JP7370076B2 - grass cutting equipment - Google Patents

Description

The present invention relates to a grass cutting device.

Patent Document 1 is disclosed as a device for cutting down plants on the ground around a support that becomes an obstacle. According to US Pat. No. 5,900,300, a mowing device adapted to be propelled by an associated vehicle includes a support, first and second arms, and first and second mower elements. The support is adapted to attach to an associated boom extending from an associated vehicle. The first arm and the second arm are pivotally attached to the support. A first mower element is said to be attached to the first arm and a second mower element is attached to the second arm. Each of the first and second arms is provided with a cylinder for rotational driving, and these cylinders are communicated with each other. In addition, mowing around obstacles is realized by arranging a plurality of various valves inside the hydraulic circuit that communicates the cylinders and using an accumulator.

US Published Patent No. 2006/0026938A1

However, the configuration of Patent Document 1 has a problem in that the configuration of the hydraulic circuit of the entire device is complicated because there are many circuits for driving and buffering the first and second arms.
Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a mowing device that can work around obstacles by simplifying the configuration of the circuit that drives and buffers the arm.
The inventor proposed the body configuration of a grass cutting device in Japanese Patent Application No. 2020-119920 “Grass Cutting Device” and Japanese Patent Application No. 2020-134176 “Grass Cutting Device”. The present invention proposes the mechanical, hydraulic, and electrical circuit relationships of these mowing devices.

This invention is
a first work arm that is rotatable about a pivot axis;
a second work arm provided separately from the first work arm and pivotable about the pivot axis;
The first working arm and the second working arm change from a first posture in which the distal ends of the first working arm and the second working arm are facing forward to a posture other than the first posture. The first working arm and the second working arm are pivotable between a second posture that is a posture state until the second working arm completely faces backward,
an actuator for rotating the first working arm;
a first switching valve that can be switched to a pressure-feeding position in which fluid is force-fed to the actuator and a no-load position in which fluid is not force-fed to the actuator;
A blocking position is disposed between the actuator and the first switching valve and blocks fluid from flowing from the actuator to the first switching valve, and a blocking position prevents fluid from flowing in and out between the actuator and the first switching valve. a second switching valve that can be switched to a freely open position;
a first sensor that detects that an obstacle has contacted the first work arm;
a second sensor that detects contact of the first work arm with the second work arm;
a third sensor that detects that the first work arm is in the first posture;
A mowing device characterized by comprising:
Pertains to.

This invention further includes:
If only the first sensor detects the detection, or if all of the first sensor, second sensor, and third sensor detect the detection, the first switching valve is switched to the no-load position, and the second switching valve is switched to the open position. switch to,
A grass cutting device characterized by
Pertains to.

This invention further includes:
When only the second sensor detects the detection, switching the first switching valve to the pressure feeding position and switching the second switching valve to the blocking position;
A grass cutting device characterized by
Pertains to.

This invention further includes:
When detected by the second sensor and the third sensor, switching the first switching valve to the no-load position and switching the second switching valve to the cutoff position;
A grass cutting device characterized by
Pertains to.

This invention further includes:
When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture a indicating the device posture,
The first working arm and the second working arm are in the first posture, which is the normal working posture, facing forward in the direction of travel, and the sensor arm that detects obstacles ahead in the direction of travel is not detecting any obstacles. , the first working arm is in contact with the second working arm,
The hydraulic circuit is
The hydraulic circuit is in the a state. In the hydraulic circuit a state, the first switching valve is in the no-load position, the second control valve is in the cutoff position, the first switching valve and the second switching valve are not conductive, and the actuator shrink and regulate
When the second sensor detects that the first working arm has contacted the second working arm and the third sensor detects that the first working arm is in the first posture, the first switching valve is set to the no-load position. At the same time, switch the second switching valve to the cutoff position,
The electrical circuit is
The electric circuit is in the a state, and in the electric circuit a state, the first sensor for detecting that an obstacle has contacted the first working arm is in the non-contact position, and the second sensor is in the non-contact position. The work arm is in the closed position and the third sensor is not detecting the detection position 525 in the second posture.
A grass cutting device characterized by
Pertains to.

This invention further includes:
When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture b indicating the device posture,
The sensor arm has detected an obstacle, the first working arm is in contact with the second working arm, and the first working arm and the second working arm are in the first posture, which is the normal working posture. can be,
The hydraulic circuit is
The hydraulic circuit is in a state B, and in the state B, the first control valve is in a no-load position, the second control valve is in an open position,
The electrical circuit is
The electric circuit is in state b, and in the electric circuit b state, the first sensor is in the contact position, the second sensor is in the first working arm, the second working arm is in the closed position, and the third sensor is in the second position. The detection position is not detected,
A grass cutting device, characterized in that the second switching valve is electrically connected via the first sensor, and the actuator is in a freely expanding and contracting state;
Pertains to.

This invention further includes:
When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture c indicating the device posture,
From the first posture in which the sensor arm has detected an obstacle, the first working arm is separated from the second working arm, and the first working arm and the second working arm are in the normal working posture, The first work arm and the second work arm are in the middle of rotation toward the second posture, and the first work arm and the second work arm are in a freely rotatable state by switching the switching valve based on detection by the sensor.
The hydraulic circuit is
The hydraulic circuit is in state B, and in the state of hydraulic circuit B, the first control valve is in the no-load position, the second control valve is in the open position, and only the first sensor 52A detects, or the first sensor and When both the second sensor and the third sensor detect the detection, the first switching valve is switched to the no-load position, and the second switching valve is switched to the open position;
The electrical circuit is
The electric circuit is in the C state, and in the electric circuit C state, the first sensor is in the contact position, the second sensor is in the first working arm, the second working arm is in the open position, and the third sensor is in the second position. A grass cutting device that detects a detection position, conducts a second switching valve via a first sensor, and has an actuator in a free expansion/contraction state (freely displaceable state);
Pertains to.

This invention further includes:
When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture d indicating the device posture,
the sensor arm is not detecting an obstacle, and the first work arm is separated from the second work arm;
The first working arm and the second working arm are in the middle of rotating from the first posture, which is a normal working posture, toward the second posture,
The hydraulic circuit is
Hydraulic circuit B is in state B, in which the first control valve is in the no-load position, the second control valve is in the open position,
The electrical circuit is
The electric circuit is in the d state, and in the electric circuit d state, the first sensor is in the non-contact position, the second sensor is in the first working arm, the second working arm is in the closed position, and the third sensor is in the second posture. The detection position of
A grass cutting device, characterized in that the second switching valve is electrically connected via the first sensor and the second sensor, and the actuator is in a freely expanding and contracting state;
Pertains to.

This invention further includes:
When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture e indicating the device posture,
The sensor arm is not detecting an obstacle, and the first work arm is in contact with the second work arm,
Both the first work arm and the second work arm are in a state of being rotated to the second posture side, and after the first work arm and the second work arm are rotated to the second posture side, the obstacle W is located between the first work arm and the second work arm. It is separated from the second working arm,
The hydraulic circuit is
Hydraulic circuit C is in state C, in hydraulic circuit C, the first control valve is in the pressure feeding position, the second control valve is in the cutoff position, and when only the second sensor detects, the first switching valve is switched to the pressure feeding position and , switch the second switching valve to the cutoff position,
The electrical circuit is
The electric circuit is in the e state, and in the electric circuit e state, the first sensor is in the non-contact position, the second sensor is in the first working arm and the second working arm are in the closed position, and the third sensor is in the second posture. The detection position of
energizing the first switching valve via the first sensor to the third sensor;
A grass cutting device, characterized in that the actuator is driven to the extension side, and the first working arm and the second working arm are returned to the first posture.
Pertains to.

According to the present invention, it is possible to provide a grass cutting device that can work around obstacles by simplifying the configuration of the circuit that drives and buffers the arm.

FIG. 1 is a plan view of a mowing device according to an embodiment of the invention. The first work arm shows an acceptable posture (first posture). The left side in the figure is the front in the direction of travel, and the top in the figure is the right side in the direction of travel, which is the side of the traveling aircraft. FIG. 1 is a side view of a mowing device according to an embodiment of the invention. The back in the figure is the front in the direction of travel, and the top in the figure is the right side in the direction of travel, which is the side of the traveling aircraft. FIG. 2 is a front view of the mowing device according to the embodiment of the present invention, and is a sectional view taken along line AA in FIG. 1 with the second metal fitting and actuator partially cut away. FIG. 3 is a plan view showing the operation of the mowing device according to the embodiment of the present invention. Indicates a state in which the sensor arm is not detecting an obstacle. This shows a state in which the first working arm is in contact with the second working arm. The first working arm and the second working arm are in a first posture (acceptable posture) which is a normal working posture. The first base member and link mechanism are omitted, and the second base member is shown in cross section. This is posture a indicating the device posture. FIG. 3 is a plan view showing the operation of the mowing device according to the embodiment of the present invention. Indicates the state in which the sensor arm has detected an obstacle. This shows a state in which the first working arm is in contact with the second working arm. The first working arm and the second working arm are in a first posture (acceptable posture) which is a normal working posture. For convenience of explanation, the first base member and the second base member are shown in cross section. Posture b indicates a device posture. FIG. 3 is a plan view showing the operation of the mowing device according to the embodiment of the present invention. Indicates the state in which the sensor arm has detected an obstacle. This shows a state in which the first working arm is separated from the second working arm. A state in which the first working arm and the second working arm are in the middle of rotation from the first posture (acceptable posture), which is a normal working posture, to the second posture (dischargeable posture) is shown. The first working arm and the second working arm are in a rotatable state by switching the switching valve (control valve) based on detection by the sensor. For the sake of explanation, the first base member and the link mechanism are omitted, and the second base member is shown in cross section. This is posture c indicating the device posture. FIG. 3 is a plan view showing the operation of the mowing device according to the embodiment of the present invention. This indicates a state in which the sensor arm is not detecting an obstacle (this is a case where the obstacle is separated from the sensor arm when the first work arm is being rotated). This shows a state in which the first working arm is separated from the second working arm. A state in which the first working arm and the second working arm are in the middle of rotation from the first posture (acceptable posture), which is a normal working posture, to the second posture (dischargeable posture) is shown. For the sake of explanation, the first base member and the link mechanism are omitted, and the second base member is shown in cross section. This is posture d indicating the device posture. FIG. 3 is a plan view showing the operation of the mowing device according to the embodiment of the present invention. Indicates a state in which the sensor arm is not detecting an obstacle. This shows a state in which the first working arm is in contact with the second working arm. The first work arm and the second work arm both show a state in which they are rotated toward the second position (ejectable position). This is a case where the obstacle is separated from the first work arm and the second work arm after the first work arm and the second work arm are rotated to the second posture (dischargeable posture). For the sake of explanation, the first base member and the link mechanism are omitted, and the second base member is shown in cross section. This is posture e indicating the device posture. FIG. 2 is a fluid pressure circuit diagram (hydraulic circuit diagram) of the mowing device according to the embodiment of the present invention (circuit a when the device is in posture a); FIG. The first control valve is in the no-load position and the second control valve is in the shut-off position. FIG. 2 is a fluid pressure circuit diagram (hydraulic circuit diagram) of the grass cutting device according to the embodiment of the present invention (circuit b is shown when the device postures are postures b, c, and d); FIG. The first control valve is in the no-load position and the second control valve is in the open position. 1 is a fluid pressure circuit diagram (hydraulic circuit diagram) of a grass cutting device according to an embodiment of the present invention. (This is circuit c when the device is in posture e, which is the posture of the device.) The first control valve is in a pumping position and the second control valve is in a blocking position. FIG. 2 is a circuit diagram of a grass cutting device according to an embodiment of the present invention (electrical circuit a). This is a state of posture a indicating the device posture. The first switching valve is in the no-load position and the second switching valve is in the cutoff position. Both the first switching valve and the second switching valve are not electrically connected. Restricts the actuator (cylinder) from shrinking. It is a circuit diagram which shows the state of the electrical connection of the grass cutting device based on the Example of this invention (electrical circuit b). This is a state of posture b indicating the device posture. The first switching valve is in the no-load position and the second switching valve is in the open position. The second switching valve is made conductive via the first sensor. The actuator (cylinder) is in a free expansion/contraction state (displaceable state). It is a circuit diagram showing the state of electrical connections of the grass cutting device according to the embodiment of the present invention (electrical circuit c), which is a state of posture c showing the posture of the device. The first switching valve is in the no-load position and the second switching valve is in the open position. The second switching valve is made conductive via the first sensor. The actuator (cylinder) is in a free expansion/contraction state (displaceable state). It is a circuit diagram showing the state of electrical connections of the grass cutting device according to the embodiment of the present invention (electrical circuit d), which is a state of posture d showing the posture of the device. The first switching valve is in the no-load position and the second switching valve is in the open position. The second switching valve is electrically connected via the first sensor and the second sensor. The actuator (cylinder) is in a free expansion/contraction state (displaceable state). It is a circuit diagram showing the state of electrical connections of the grass cutting device according to the embodiment of the present invention (electrical circuit e), which is a state of posture e showing the device posture. The first switching valve is in the pressurized load position, and the second switching valve is in the blocking position. The first switching valve is made conductive via the first to third sensors. The actuator (cylinder) is driven to the extension side, and the first working arm and the second working arm are returned to the first posture (acceptable posture).

A is a grass cutting device as a working machine. The mowing device A is attached to a traveling vehicle (not shown) such as a tractor using one or more mowing device attachment arms (not shown).
The mowing device A is connected to a boom device or the like. The boom device (extensible means) is similar to the patent application No. 2019-194694 "Working machine", the patent application No. 2020-14070 "Working machine", etc., and the boom device (extension/contraction means) is similar to the patent application No. 2020-84471 "Attachment/detachment mechanism and work machine equipped with attachment/detachment mechanism". Connected by a connecting mechanism. Note that the mowing device A of the present application is not limited to the illustrated boom device (extensible means) as shown in the illustration of “grass mowing device” in the prior application, JP-A No. 2019-187386 (Japanese Patent Application No. 2018-087440).

In the grass cutting device A, 11 is a base member. The base member 11 includes a first base member 111 and a second base member 112. 21 is a first working arm, and 31 is a second working arm. B is a parallel link mechanism.
The first working arm 21 and the second working arm 31 are attached to a traveling machine body such as a tractor through a grass cutting device attachment arm also called a boom device, which is a plurality of members, and the grass cutting device A is attached to the front of the traveling machine body or Work from the rear or side. When attached to an arm for attaching a grass cutting device, the connecting portion 61 provided on the first base member 111 is used to connect to the tip of the arm for attaching a grass cutting device.

The grass cutting device A can be mounted on the side of the traveling machine via a plurality of grass cutting device attachment arms, or it can be attached to the rear of the traveling machine via a grass cutting device mounting arm that can be moved to the left and right of the traveling machine. It is possible to select whether the mowing device is mounted at the rear or side of the traveling machine via the mowing device mounting arm that is movable from side to side. Furthermore, the mowing device A may be attached directly to the traveling machine body or a three-point link lifting device of the traveling machine body, etc., without using a mowing device attachment arm.
The mowing device A is capable of sandwiching an obstacle W between a first work arm 21 and a second work arm 31, which are rotatably provided in the shape of scissors. Each of the arms 31 can rotate to perform work. The tip sides of the scissor-shaped first working arm 21 and second working arm 31 that are away from the rotational fulcrum axis are directed in the direction of movement. The distal end sides of the illustrated first working arm 21 and second working arm 31 are curved in an arc shape.

The base member 11 is provided in the mowing device A. The first base member 111 (11) is attached to the traveling body side of the parallel link mechanism B. The second base member 112 (11) is provided at one end of the parallel link mechanism B on the distal end side. The second base member 112 (11) is horizontally movable via the parallel link mechanism B with respect to the first base member 111 (11) provided on the other end side of the parallel link mechanism B.

12 is a pivot axis. The pivot shaft 12 is provided on the second base member 112 and consists of a vertical shaft oriented in a direction intersecting the work surface. Each of the first work arm 21 and the second work arm 31 is capable of horizontal rotation about the pivot shaft 12 as a fulcrum axis. Further, depending on the rotational postures of the first working arm 21 and the second working arm 31, the receiving posture (first posture) and the discharging possible posture (second posture) are assumed.
The first work arm 21 is provided so as to be pivotable about the pivot shaft 12 between a first attitude and a second attitude. The second working arm 31 is provided separately from the first working arm 21 and is provided so as to be pivotable about the pivot shaft 12 between the first attitude and the second attitude.
A description of these postures will be given later.

15 is a stopper. The stopper 15 is provided on the second working arm 31.
16 is a first metal fitting, and 17 is a second metal fitting. The first metal fitting 16 and the second metal fitting 17 are connected to each other and are attached to connect the second base member 112 (11) around the pivot shaft 12 and the first working arm 21. The first metal fitting 16 and the second metal fitting 17 rotate in the vicinity of the rotation axis 12 while being connected to each other as the first work arm 21 rotates around the rotation axis 12 .

The pivot shaft 12 is provided closer to the attachment position of the front arm 13A attached to the second base member 112 (11) than the attachment position of the rear arm 13B attached to the second base member 112 (11). That is, since the pivot shaft 12 is located on the front side with respect to the second base member 112 (11), the tips of the first work arm 21 and the second work arm 31 connected to the pivot shaft 12 are located further on the front side. be able to.

The parallel link of the parallel link mechanism B consists of a front arm 13A on the side closer to the obstacle W that the work arm comes into contact with when it comes into contact with the obstacle, and a rear arm 13B on the side farther from the obstacle W. The parallel link mechanism B is rotatably provided at one end on the first base member 111 (11) and at the other end on the second base member 112 (11), and is rotatable in a direction parallel to the work surface. be. That is, the second base member 112 (11) can be moved in parallel with the first base member 111 (11). The parallel link mechanism B has an expanded position or a retracted position depending on the rotational positions of the front arm 13A and the rear arm 13B. A description of these positions will be given later.

The parallel link mechanism B is directed outward from the first base member 111 (11) to the left and right with respect to the traveling direction in the expanded position described later. As a result, when the first work arm 21 and the second work arm 31 come into contact with the obstacle W, the first work arm 21 and the second work arm 31 move the obstacle W to the first work arm 21 and the second work arm 31. It is possible to passively move horizontally or move parallel to the ground to the rear and to the inner side in the width direction with respect to the traveling direction, so as to be sandwiched between the two.

The acceptable posture (first posture) in the postures such as the orientation of the first working arm 21 and the second working arm 31 is as in the first working arm 21 and the second working arm 31 shown in FIGS. 1 and 4. The first working arm 21 and the second working arm 31 may not be in contact with the obstacle W, or may be in contact with the obstacle W, as in the case of the first working arm 21 and the second working arm 31 shown in FIG. A posture in which the tip of the head is facing forward. It does not matter whether the parallel link B is in an acceptable attitude (first attitude), ie, a deployed position or a retracted position, which will be described later.
The ejectable posture (second posture) in the postures of the first working arm 21 and the second working arm 31, etc., means that the first working arm 21 and the second working arm This refers to a posture in which the work arm 31 is in contact with an obstacle W and rotated horizontally from an acceptable posture (first posture), and subsequent postures.

The ejectable posture (second posture) is the first working arm 21 and the second working arm 31 other than the acceptable posture (first posture) of the first working arm 21 and the second working arm 31 shown in FIGS. 1, 4, and 5. 2. This refers to the posture state until the work arm 31 completely faces backward. A state in which only the first work arm 21 is rotated rearward with respect to the traveling direction is also an ejectable posture (second posture). It does not matter whether the parallel link B is in the deployable position or the retracted position, which will be described later, which are the posture states of the parallel link B in the ejectable posture (second posture).
In this specification, the first posture (acceptable posture) refers to a position in which the distal ends of the first working arm 21 and the second working arm 31 in the radial direction with respect to the center of rotation face forward, and from this position (even slightly) The position (range) rotated to the rear side is called the second posture (ejectable posture).

The first working arm 21 is provided so as to be pivotable about the pivot shaft 12 between an accepting posture (first posture) and an ejectable posture (second posture).
The second work arm 31 is provided separately from the first work arm 21 and is rotatable about the pivot shaft 12 between a receptive position (first position) and an ejectable position (second position). Provided for.

The deployed position of the parallel link mechanism B is a state in which the arms of the first working arm 21 and the second working arm 31 provided in the parallel link mechanism B are deployed outward and laterally in the width direction with respect to the traveling direction. Refers to the state shown in 1.
The retracted position of the parallel link mechanism B is a state in which the first working arm 21 and the second working arm 31 are moved inward in the width direction with respect to the traveling direction from the deployed position.

41 is a first elastic body. The first elastic body 41 is provided on the side of the rear arm 13B of the parallel link mechanism B.
The first elastic body 41 is made of a gas spring, a coil spring, etc., and in the embodiment of the present invention, a gas spring is used. The first elastic body 41 is attached at both ends to the first base member 111 (11) and the second base member 112 (11) side of the rear arm 13B, as shown in FIG. 1 and below.

The first elastic body 41 can change the position of the parallel link mechanism B between a deployed position and a retracted position, and can also move the second base member 112 (11) to the deployed position with respect to the first base member 111 (11). The side is always energized.
The parallel link mechanism B is always biased forward and outward with respect to the traveling direction by the first elastic body 41. The parallel link mechanism B, which is not in contact with the obstacle W, etc., can return to the deployed position and wait for the obstacle W, which approaches as the vehicle advances.

Since the first elastic body 41 is disposed on the rear side of the rotating shaft 12, it does not come into direct contact with obstacles that approach as the vehicle moves forward.
42 is a second elastic body. The second elastic body 42 is made of a gas spring, a coil spring, or the like, and in the embodiment of the present invention, a gas spring is used. The second elastic body 42 spans and connects the first working arm 21 and the second working arm 31, and always urges the second working arm 31 toward the first working arm 21 side.

That is, the second elastic body 42 constantly biases the first working arm 21 and the second working arm 31 in a direction in which they approach each other. Therefore, the first working arm 21 and the second working arm 31 can perform mowing work while contacting the obstacle W, and plants around the obstacle W can be reliably cut. Moreover, since the second elastic body 42 biases the second working arm 31 regardless of the first posture or the second posture, the first working arm and the second working arm 31 can avoid the obstacle W even during the posture change. It can be inserted properly.
The second elastic body 42 is provided on the outside of the second work arm 31, not on the inside where the obstacle W is sandwiched between the first work arm 21 and the second work arm 31. Therefore, when the first work arm 21 and the second work arm 31 work with the obstacle W in between, the second elastic body 42 does not come into contact with the obstacle.

The first working arm 21 and the second working arm 31 each consist of a substantially plate-shaped body.
As shown in FIGS. 2 and 3, the first work arm 21 and the second work arm 31 are stacked and can be pivoted in the horizontal direction about the pivot shaft 12 attached to the base member 112 (11). It is attached to the second base member 112 (11). The first working arm 21 and the second working arm 31 each have a first cutting blade part 24 and a second cutting blade part 34, which are rotationally driven by cutting blade motors 242 and 342, on their distal ends. The first working arm 21 and the second working arm 31 are capable of mowing work using the first cutting blade part 24 and the second cutting blade part 34 while coming into contact with an obstacle W existing on the work surface.
The second work arm 31 is provided separately from the first work arm 21 and is provided so as to be rotatable around the pivot shaft 12 independently of the first work arm 21, so that when it comes into contact with an obstacle W, It is arranged to face the first working arm 21 with the obstacle W in between.

The first working arm 21 includes an operating means (actuator, cylinder) 14 that is an operating means for driving rotation of the first working arm 21 .
The operating means 14 in this embodiment consists of an actuator and a hydraulic cylinder. The operating means 14 is attached to the base member 11. In this embodiment of the invention, the actuating means 14 is attached to the rear part of the second base member 112. 141 is a rod provided at the tip of the operating means 14. The rod 141 is expanded and contracted by the operating means 14, which is a hydraulic cylinder. The operating means 14 swings and drives the first working arm 21 .

The operating means (actuator, cylinder) 14 expands and contracts the rod 141 and rotates the first working arm 21 via the first metal fitting 16 and the second metal fitting 17.
Since the first work arm 21 is provided so as to be pivotable about the pivot shaft 12, the first work arm 21 can pivot by coming into contact with an obstacle W existing on the work surface.

The stopper 15 provided on the second working arm 31 restricts the rotation of the second working arm 31 that is in contact with the first working arm 21 that is rotationally driven by the operating means 14 .
The stopper 15 can stably maintain the positions of the first working arm 21 and the second working arm 31 in the acceptable posture (first posture), and allows the worker to avoid the obstacle W and the second working arm 31. It is easy to adjust the contact position to an appropriate position.
The stopper 15 can come into contact with the second base member 112 (11) and restricts rotation. As shown in FIGS. 1, 4, and 5 to 8, the stopper 15 comes into contact with the front end of the second base member 112 (11) to prevent the second work arm 31 from separating from the first work arm 21. Since the movement toward the traveling aircraft body side, which is the intended direction, is restricted, the acceptable attitude (first attitude) can be maintained.

The operation by the rod 141 of the operating means 14, which is extended and contracted by a hydraulic cylinder, restricts the operation of the first working arm 21 and the second working arm 31 within a movable range until the stopper 15 restricts the movement.
The stopper 15 maintains the opening angle of the first working arm 21 and the second working arm 31 at an acute angle in the acceptable posture (first posture) and the acceptable posture (first posture), so that the working area of the mowing device A is The grass does not spread unnecessarily and mowing work can be carried out smoothly.

23 is a contact portion. The contact portion 23 is provided between the pivot shaft 12 of the first working arm 21 and the first cutting blade portion 24 which is a working portion. The contact portion 23 is provided in a concave shape. The obstacle W that has reached the contact portion 23 presses the contact portion 23 to rotate the first working arm 21 rearward.
24 is a first cutting blade section. The first cutting blade section 24 is a cutting blade, a cutting blade section, or a working section. The first cutting blade portion 24 is attached to the lower portion of the first working arm 21 on the radial tip side with respect to the rotation shaft 12 . The first working arm 21 has one or more cutting blades at its lower portion.

The second working arm 31 has one or more cutting blades at its lower portion. In this embodiment, the second cutting blade part 34 is provided at the lower part of the second working arm 31 on the radial tip side with respect to the rotation shaft 12. The second cutting blade portion 34 may be additionally provided near the pivot shaft 12 of the second working arm 31.
The second cutting blade section 34 is a cutting blade, a cutting blade section, or a working section.

The first working arm 21 and the second working arm 31 are attached to the second base member 112 (11) so as to be pivotable in the horizontal direction about the pivot shaft 12, and the first cutting blade part 24 and the second cutting blade part 34 is horizontally movable.
Therefore, while the first work arm 21 and the second work arm 31 sandwich the obstacle W between their opposing inner sides, the first cutting blade part 24 and the second cutting blade part 34 cut grass around the entire circumference of the obstacle W. mow.

241 and 341 are cutting blades, respectively. Four cutting blades 241 are provided on the rotation axis of the first cutting blade part 24, and four cutting blades 341 are provided on the rotation axis of the second cutting blade part 34 at equal intervals. Note that there is no limit to the number of cutting blades 241, 341 that the first cutting blade part 24 and the second cutting blade part 34 have.
As shown in FIGS. 1 and 2, the cutting blades 241 and 341 provided in the first cutting blade part 24 and the second cutting blade part 34, respectively, rotate in the horizontal direction when viewed from the traveling direction.

242, 342 are hydraulic motors. The hydraulic motor 242 is attached to the motor base of the first work arm 21 on the rotation center axis of the first cutting blade section 24 . Note that the hydraulic motor 242 may be replaced with an electrically operated electric motor.
The hydraulic motors 342 are respectively provided on the rotation center axis of the second cutting blade section 34 at the motor base of the second working arm 31 .
The hydraulic motor 242 and the hydraulic motor 342 rotate the cutting blade 241 and the cutting blade 341 provided in the first cutting blade part 24 and the second cutting blade part 34, respectively.

5 is a detection section. The detection section 5 is provided close to the first cutting blade section 24, which is the working section, and is located outside in the radial direction of the rotational diameter of the first cutting blade section 24, which is the working section, as shown in FIG. 1 and below. It is possible to detect an obstacle by locating it so as to protrude laterally, so that the side portion contacts the obstacle W and sinks into the rotation center side of the first cutting blade portion 24 .
51 is a sensor arm. The sensor arm 51 is provided in the detection section 5. The sensor arm 51 is a contact sensor and is provided along the front outer periphery of the first working arm 21 .

The sensor arm 51 includes a first sensor arm 511 and a second sensor arm 512. A first sensor arm 511 and a second sensor arm 512 constituting the detection unit 5 are provided so as to be horizontally rotatable.
As shown in FIGS. 1, 4 to 8, the first sensor arm 511 is attached with one end protruding outward from the left side to the front side in the direction of movement of the first work arm 21. The second sensor arm 512 has one end attached to the inner side of the outer end of the first sensor arm 511 attached to the first working arm 21, which is the side through which the obstacle W of the first working arm 21 passes.

The first sensor arm 511 and the second sensor arm 512 are installed partially overlapping each other. The first sensor arm 511 has a rotation fulcrum shaft 511a provided on the outer end on the left side in the direction of travel, and the second sensor arm 512 has a rotation fulcrum shaft 512a on the outer end on the left side in the travel direction. It can be rotated horizontally.
As shown in FIG. 1, the first sensor arm 511 and the second sensor arm 512, which are sensor arms 51 in a state of not detecting an obstacle W, extend outward from the first cutting blade part 24, which is a working part, in a plan view. It is in an outstanding state.

By configuring the sensor arm 51 of the detection unit 5 with a plurality of first sensor arms 511 and second sensor arms 512, the tip part of the first sensor arm 511 remote from the rotation fulcrum shaft 511a and the working part Detection accuracy can be improved while maintaining the separation distance from the first cutting blade part 24 within a certain range.
Since the tip of the sensor arm 51 can be kept within a certain distance from the first cutting blade part 24, which is the working part, it is possible to detect obstacles within a certain distance from the first cutting blade part 24, which is the working part. can.

The first sensor 52A is provided in the detection unit 5 so as to be able to contact a contact portion 53A provided near the pivot shaft 511a of the first sensor arm 511.
The first sensor 52A can generate a signal indicating whether or not the sensor arm 51 has rotated by contacting the contact portion 53A.

The first sensor 52A assumes a contact position 521 shown in FIGS. 12 to 16 showing electrical circuit diagrams when the contact portion 53A comes into contact, and assumes a non-contact position 522 when the contact portion 53A does not make contact. Take. That is, if the sensor arm 51 does not contact an obstacle, the first sensor 52A is in the non-contact position 522, and if the sensor arm 51 contacts an obstacle, the first sensor 52A is in the contact position 521.
The contact portion 53A included in the sensor arm 51 is composed of a so-called cam piece. The contact portion 53A is rotatable together with the first sensor arm 511 and can contact the first sensor 52A.
By changing the shape of the periphery of the contact portion 53A, it is possible to change the transmission timing of the signal emitted by the first sensor 52A.

54 is a biasing body. The biasing body 54 is provided in the detection section 5 . The biasing body 54 biases the sensor arm 51 toward the radially outer side with respect to the rotation axis of the first cutting blade portion 24, which is a working portion.
55 is a connecting portion. The connecting portion 55 includes a sliding portion 551 and a pin 552. The sliding portion 551 is formed in the shape of a long hole in the first sensor arm 511, which is one sensor arm.

The connecting portion 55 connects one end of the first sensor arm 511 , which is the sensor arm 51 , to the intermediate portion of the second sensor arm 512 . The connecting portion 55 connects one end of the first sensor arm 511 and the intermediate portion of the second sensor arm 512.
The pin 552 is provided on the second sensor arm 512, which is the other sensor arm, so as to protrude toward the sliding portion 551, and is fitted into the sliding portion 551. The pin 552 is slidable on the sliding portion 551 within a long hole provided in the sliding portion 551.

The sliding portion 551 has a long hole shape and is provided on the first sensor arm 511. The sliding portion 551 is provided so as to become farther away from the rotation fulcrum shaft 511a of the first sensor arm 511 as it goes in the longer diameter direction. The pin 552 provided on the second sensor arm 512, which is another sensor arm, can interlock the rotation of the sensor arms 511 and 512 by sliding on the inner periphery of the elongated hole of the sliding portion 551. . Note that the shape of the sliding portion 551 and the positions of the sliding portion 551 and the pin 552 can be freely set in consideration of the detection sensitivity, the shape of the first cutting blade portion 24 which is the working portion, etc.

56 is a curved portion. The curved portion 56 is formed on the sensor arm 51 so as to curve along the first cutting blade portion 24, which is a working portion.
The outer side surface of the curved portion 56 is provided so as to be positioned so as to approximately coincide with the outer peripheral edge of the side surface of the first cutting blade section 24, which is the working section, in a plan view when the detection section 5 is in the detection state. Alternatively, it is provided so as to be located inside the outer peripheral edge of the side surface of the first cutting blade section 24, which is the working section.

Since the distal end of the first working arm 21 in a plan view is provided so as to cover the first cutting blade part 24, the first cutting blade part 24 does not protrude from the first working arm 21 and can avoid obstacles W. The first cutting blade portion 24 does not come into contact with. In the case of the embodiment of the present invention, the distal end of the first working arm 21 is curved in an arc shape, so that the outer circumferential edge of the first working arm 21 rotates while contacting the obstacle W, thereby preventing the obstacle from being removed. W can be smoothly guided to the contact portion 23.

When the sensor arm 51 is in the detection state in which it is in contact with and presses the sensor arm 51, the sensor arm 51 is aligned with the outer periphery of the first work arm 21 or is located inside the outer periphery of the first work arm 21 and in the first mowing section which is the working part. It is located outside the rotation diameter of the blade portion 24. That is, it is possible to work at a position where the first cutting blade section 24 is as close to the obstacle W as possible. In addition, when an obstacle W sandwiched between the first work arm 21 and the second work arm 31 and heading towards the contact part 23 passes by the side of the first cutting blade part 24 which is a work part, the sensor in the detection state Since the arm 51 does not protrude laterally from the working part, it does not obstruct the working part from approaching the obstacle W as much as possible. Therefore, the first cutting blade part 24 and the second cutting blade part 34 can cut the grass growing around the obstacle W as close as possible to the obstacle W without being obstructed by the sensor arm 51.

In the embodiment of the present invention, when the obstacle W toward the contact portion 23 passes by the side of the first cutting blade portion 24 and the second cutting blade portion 34, which are working portions, the obstacle W is not contacted. are the first working arm 21, the second working arm 31, and the sensor arm 51. Therefore, the obstacle W can be guided to the contact portion 23 along the outer periphery of the first working arm 21 and the outer periphery of the second working arm 31.

Since the horizontally rotating sensor arm 51 is provided with the curved portion 34, even if the outer peripheral edge of the first work arm 21 to which the sensor arm 51 is attached is curved, the sensor arm 51 can be arranged along this curve. . In addition, since the sensor arm 51 can be arranged so as to almost coincide with the edge of the first cutting blade section 24, which is the working section, in a plan view in the detection state, the sensor arm 51 is separated from the first cutting blade section 24, which is the working section. It does not protrude in the direction of the obstacle W, and it is possible to prevent excessive pressing force from being applied to the sensor arm 51 and the obstacle W.
The tip of the sensor arm 51 formed of a plurality of sensor arms remote from the rotational fulcrum does not protrude outward to a large extent compared to when the sensor arm 51 is formed of only one sensor arm, so the installation space can be reduced. Space can be used effectively and parts can be properly arranged.

When the obstacle W comes into contact with the sensor arm 51, the sensor arm 51 rotates backward. Then, the first sensor 52A installed at the rear of the sensor arm 51 is pushed through the contact portion 53A and brought into a detection state.
Although the sensor arm 51 is provided along the front outer periphery of the first working arm 21 in this embodiment, it may also be provided along the front outer periphery of the second working arm 31 to perform the same function. .

The sensor arm 51 of the detection unit 5 includes a plurality of first sensor arms 511 and second sensor arms 512. However, since the first sensor arm 511 and the second sensor arm 512, which are the sensor arms 51, have a connected structure, it is sufficient to arrange only one sensor that emits a signal. Therefore, the wiring and circuits that send signals and the internal program of the control unit that processes these signals can be simplified.
Furthermore, by connecting the plurality of sensor arms 51, the moving distance associated with rotation of the tip end of the sensor arm can be shortened. When each sensor arm 51 rotates due to contact/pressure with an obstacle W, the variation in sensor detection accuracy caused by the difference in distance from each rotation fulcrum 511a, 512a to the position pressed by the obstacle W is calculated as follows: It can be made as small as possible, and the reliability of detecting the obstacle W is improved.

The rotation of the first sensor arm 511 is interlocked and transmitted to the second sensor arm 512, which is another sensor arm, through the connection part 55, and the second sensor arm 512, which is another sensor arm, is also transmitted in the same way. Rotate in the same direction. Further, when the second sensor arm 512, which is another sensor arm, is pressed by an obstacle W and the second sensor arm 512 rotates, the second sensor arm, which is another sensor arm, is The rotation of the arm 512 is transmitted to the first sensor arm 511, and the first sensor arm 511 similarly rotates in the same direction, activating the switch.

Each sensor arm 51 (first sensor arm 511, second sensor arm 512) rotates in the horizontal direction, and a plurality of sensor arms 51 (first sensor arm 511, second sensor arm 512) are arranged one on top of the other in the horizontal direction, with some parts overlapping each other. Since there are no horizontal gaps or steps between the sensor arms 51 (first sensor arm 511, second sensor arm 512), the obstacle W will not be caught or caught.
This point is important in the embodiment of the present invention because the work is performed while the obstacle W slides horizontally with respect to the sensor arm 51.

Rotate the first work arm 21 and the second work arm 31 from the receptive posture (first posture) to the ejectable posture (second posture), or from the ejectable posture (second posture) to the receptive posture (first posture). In order to do this, the rod 141 of the operating means 14 is telescopically operated. The sensor arm 51 is used to control the operation of the rod 141 in this manner.
By expanding and contracting the rod 141 of the operating means 14, the first working arm 21 and the second working arm 31 are rotated around the obstacle W, thereby preventing damage caused by arm collision with the obstacle W.
The sensor arm 51 serves as a sensing mechanism for actively turning the device with respect to the obstacle W.

52B is a second sensor. 53B is a contact portion. The second sensor 52B is provided near the periphery of the rotational fulcrum shaft 12 of the first working arm, and is provided so as to be able to come into contact with the contact portion 53B provided near the periphery of the rotational shaft 12 of the second working arm 31. Since the second sensor 52B and the contact part 53B are installed near the rotating shaft 12, they can be placed away from the first cutting blade part 24 and the second cutting blade part 34, which are working parts. Therefore, it is possible to prevent erroneous detection or damage caused by grass or the like around the obstacle W coming into contact with the second sensor 52B.

The contact portion 53B contacts the second sensor 52B when the first working arm 21 and the second working arm 31 are relatively closed and their tips come into contact with each other. Conversely, when the first working arm 21 and the second working arm 31 are relatively opened and their tips are out of contact with each other, the contact portion 53B is out of contact with the second sensor 52B. . The second sensor 52B and the contact portion 53B are arranged in the vicinity of the rotational fulcrum shaft 12 of the first working arm and around the rotational shaft 12 of the second working arm 31, respectively, so as to have such a positional relationship. Set up nearby. The second sensor 52B can detect the relative opening and closing of the first working arm 21 and the second working arm 31 based on the presence or absence of contact with the contact portion 53B.

The second sensor 52B determines whether the second working arm 31 and the first working arm 21 are in a closed state and whether the second working arm 31 and the first working arm 21 are in contact with each other. It is detected whether the first working arm 21 is in an open state and the second working arm 31 and the first working arm 21 are not in contact with each other.
The second sensor 52B can issue a signal indicating whether or not the second working arm 31 and the first working arm 21 have rotated relative to each other by contacting or non-contacting the contact portion 53B.

As shown in the circuit diagrams shown in FIGS. 12 to 16, the second sensor 52B is in an open position 523 in which the first working arm 21 is relatively open with respect to the second working arm 31, and in an open position 523 in which the first working arm 21 is opened relative to the second working arm 31. It assumes a closed position 524 relative to the second working arm 31 . The second sensor 52B detects opening and closing of the first working arm 21 with respect to the second working arm 31 by switching an electric circuit within the second sensor 52B depending on whether or not the contact portion 53B is touched. When the first working arm 21 takes the open position 523 and the closed position 524 shown in FIGS. 12 to 16, it is detected that the first working arm 21 has contacted the second working arm 31. do.

The contact portion 53B has a so-called planar shape. Since the contact portion 53B is provided near the rotation shaft 12, which is the rotation fulcrum of the second work arm 31, it rotates together with the second work arm 31.
By changing the protruding shape or curved shape of the surface of the abutting portion 53B, the timing at which the second sensor 52B emits the signal can be changed. In addition to the embodiment, the contact portion 53B may be a contact piece made of a so-called cam piece. In this case, the contact portion 53B is configured to connect the second work arm 31 and the first work arm 21 by bringing the peripheral edge protruding from the second work arm 31 toward the first work arm into contact with the second sensor 52B. The open/close state is detected by the second sensor 52B.
The second sensor 52B is pushed through the contact portion 53B and detects that the second working arm 31 and the first working arm 21 are relatively closed and in contact.

52C is a third sensor. The third sensor 52C is provided near the rotation axis 12 of the second base member 112 (11).
53C is a contact portion. The contact portion 53C is provided at the upper part of the first working arm 21 and near the rotation axis 12 which serves as a rotation fulcrum. The contact portion 53C is integrally formed with the first working arm 21 by a boss provided coaxially with the rotating shaft 12, and rotates together with the first working arm 21.
By contacting the contact portion 53C, the third sensor 52C can issue a signal indicating whether or not the first working arm 21 has rotated relative to the second base member 112 (11). .

The third sensor 52C detects whether the first work arm 21 is in the first posture.
Reference numeral 525 shown in FIGS. 14 to 16 illustrating the electric circuit of the embodiment of the present invention is a detection position that detects that the first working arm 21 is in the second posture when the circuit is made conductive by the third sensor 52C. be. On the other hand, the detection position 525 shown in FIGS. 12 and 13 is a state in which the circuit is interrupted by the third sensor 52C, and the first work arm 21 is located relative to the second base member 112 (11). The circuit is made to recognize that it is the first posture with no rotation. The second posture detection position 525 detects the position of the second work arm 31 by the third sensor 52C.
Although the portion of the contact portion 53C that contacts the third sensor 52C is made of a planar member in the example, it may be a so-called cam piece.
By changing the shape of the periphery of the contact surface of the contact portion 53C, the timing at which the third sensor 52C issues the signal can be changed.

The configurations of the hydraulic circuit and electric circuit will be explained.
As shown in FIGS. 9 to 11 showing fluid circuit diagrams, the operating means 14, which is also called an actuator or a cylinder, consists of a bottom side chamber 143 and a rod side chamber 142. The rod 141 of the actuator 14 is expanded and contracted by the hydraulic pressure flowing into the bottom side chamber 143 and the rod side chamber 142 .
The actuator 14 rotates the first working arm 21 by extending and contracting the rod 141 .
73 is a storage tank. The storage tank 73 stores fluid. In the embodiment, oil, which is a liquid, is used as the fluid.

74 is a fluid pressure generation source (pump). A fluid pressure generation source (pump) 74 is connected to the storage tank 73 and sends the hydraulic pressure of the storage tank 73 to the downstream side.
75 is a first switching valve (first control valve). The first switching valve 75 communicates with the downstream side of the fluid pressure generation source (pump) 74 via the feed pipe line 71a.
The first switching valve (first control valve) 75 has a pressure-feeding position 751 that pumps fluid to the actuator 14 located downstream from the first switching valve (first control valve) 75, and a pressure-feeding position 751 that does not force-feed fluid to the actuator 14. It is possible to switch to each of the load positions 752.
76 is a second switching valve. The second switching valve 76 is disposed downstream of the first switching valve 75 and upstream of the actuator 14, and communicates with it via the feed pipe 71b.

The second switching valve (second control valve) 76 communicates between the bottom side chamber 143 of the actuator 14 and the first switching valve (first control valve) via a feed pipe line 71c. The second switching valve (second control valve) 76 has a cutoff position 761 that cuts off fluid from the actuator 14 to the first switching valve (first control valve) 75 side, and a cutoff position 761 that cuts off fluid from the actuator 14 to the first switching valve (first control valve) side. The opening position 762 allows fluid to freely flow in and out between the valve) 75 side and the open position 762.
The rod-side chamber 142 of the actuator 14 communicates with the first switching valve (first control valve) 75 via a return pipe 72a.
The first switching valve (first control valve) 75 communicates with the storage tank 73 through a return pipe 72b.
A relief valve 77 is provided between the sending pipe line 71c and the return pipe line 72a. Details of the relief valve 77 will be described later.

The configuration of the electric circuit will be explained with reference to FIGS. 12 to 16.
The first sensor 52A detects movement of the sensor arm 51 due to the obstacle W coming into contact with the sensor arm 51.
The first sensor 52A can take a contact position 521 and a non-contact position 522. By switching to either the contact position 521 or the non-contact position 522, the electric circuit is selectively branched into a circuit heading toward the first switching valve 75 or a circuit heading toward the second switching valve 76. .

The second sensor 52B detects whether the first working arm 21 and the second working arm 31 are closed and in contact with each other. The second sensor 52B has an open position 523 where the first working arm 21 and the second working arm 31 are relatively open and not in contact, and an open position 523 where the first working arm 21 and the second working arm 31 are relatively closed and in contact. A closed position 524 is possible. By switching the second sensor 52B to either the open position 523 or the closed position 524, the first sensor 52A switches to the non-contact position 522, and the electric circuit branched to the first switching valve 75 side is switched again. It is possible to branch into an open position 523, which is a circuit toward the second switching valve 76 side, and a closed position 524, which is a circuit toward the first switching valve 75 side.

The third sensor 52C detects whether the second work arm 31 is in the first posture. It is possible to branch off at the closed position 524 and disconnect the circuit heading toward the first switching valve 75 side. The third sensor 52C interrupts the circuit to the first switching valve 75 when the second working arm 31 is in the first posture, and blocks the circuit going to the first switching valve 75 when the second working arm 31 is in the second posture. You can connect the circuit going to.

The actuator 14 drives the pivoting motion of the first working arm 31 using fluid pressure.
The fluid pressure generation source 74 can send fluid pressure to the actuator 14 via the feed line 71a, the feed line 71b, and the feed line 71c.
The return pipe line 72a and the return pipe line 72b return fluid pressure from the actuator 14 to the storage tank 73.
The second switching valve 76 is disposed between the actuator 14 and the first switching valve 75 side, and is a check circuit from the first switching valve 75 side to the actuator 14 side as shown in FIGS. 9 and 11. A blocking position 761 that blocks fluid from the actuator 14 to the first switching valve 75 side while allowing fluid movement between the actuator 14 and the first switching valve 75 side as shown in FIG. It is possible to switch to each of the open positions 762, which allow free entry and exit.

The relief valve 77 is operated when the second switching valve 76 is in the cutoff position 761 and the first switching valve 75 is in the open position 762, as shown in FIG. In this case, it is possible to form a communication state in which the feed line 71c and the return line 72a between the second switching valve 76 and the actuator 14 are communicated with each other. Further, as shown in FIG. 11, the relief valve 77 is operated when the second switching valve 76 is in the cutoff position 761 and the first switching valve 75 is in the pressure feeding position 751, and the feeding pipe line 71a and the feeding pipe line 71b are , when the pressure in the sending pipe line 71c increases, it is possible to form a communication state in which the sending pipe line 71c and the return pipe line 72a are communicated with each other.
When the relief valve 77 is in communication between the sending pipe line 71c and the return pipe line 72a, no fluid pressure is applied to the actuator 14, so the actuator 14 is in a freely displaceable state.

The first switching valve 75 is located between the fluid pressure generation source 74 and the second switching valve 76, and has a pressure feeding position 751 where fluid is pumped to the actuator 14 and a no-load position 752 where fluid is not pumped to the actuator 14. It is possible to switch to
The state of communication between the sending pipe line 71c and the return pipe line 72a by the relief valve 77 can be established regardless of the pressure feeding position 751 and the no-load position 752 of the first switching valve 75.

The relationship between the posture of the mowing device A, the hydraulic circuit, and the electric circuit will be explained.
The mowing device A according to the embodiment of the present invention sequentially takes postures from posture a indicating the device posture to posture e indicating the device posture. Depending on the respective postures, the hydraulic circuit sequentially assumes the states of hydraulic circuits a to c, and the electric circuit sequentially assumes the states of electrical circuits a to e.

(Position a indicating the device posture)
The relationship between the posture of the mowing device A, the hydraulic circuit, and the electric circuit in posture a indicating the device posture will be explained.
In posture a, which indicates the device posture, the mowing device A has the first work arm 21 in an acceptable posture (first posture), as shown in FIGS. 1 and 4 . The sensor arm 51 (511, 512) is not detecting the obstacle W. The first working arm 21 is in contact with the second working arm 31. The first working arm 21 and the second working arm 31 are in a first posture (acceptable posture) which is a normal working posture.

(Hydraulic circuit a)
In posture a indicating the device posture, the hydraulic circuit is in the hydraulic circuit a state illustrated in FIG. The first control valve 75 is in the no-load position 752 and the second control valve 76 is in the shut-off position 761. Although both the first switching valve (control valve) 75 and the second switching valve (control valve) 76 are electrically connected, the fluid pressure generated by the fluid pressure source 74 is caused by the first control valve 75 in the no-load position 752. is connected from the feed line 71a to a return line 72b communicating inside the no-load position 752. Therefore, fluid pressure does not flow from the fluid pressure generation source 74 to the feed pipe line 71b. Further, the check circuit at the blocking position 761 prevents the fluid in the bottom chamber 143 and the feed pipe line 71c from flowing toward the feed pipe line 71b, thereby restricting the actuator (cylinder) 14 from contracting. That is, the first working arm 21 and the second working arm 31 shown in FIGS. 1 and 4 can maintain the first attitude (acceptable attitude).
As shown in FIGS. 1, 4, 9, and 12, the first sensor 52A is not detecting the obstacle W, and the second sensor 52B is not detecting the obstacle W between the second work arm and the first work arm. When contact is detected and the third sensor 52C detects that the second working arm is in the first posture, the first switching valve (first control valve) 75 is switched to the no-load position 752, and the second switching valve is switched to the no-load position 752. (Second control valve) 76 is switched to the cutoff position 761.

(Electrical circuit a)
In posture a indicating the device posture, the electric circuit is in the electric circuit a state illustrated in FIG. The first sensor 52A is in a non-contact position 522. The second sensor 52B is in the closed position 524 because the first working arm 21 and the second working arm 31 are relatively closed and in contact with each other. The third sensor 52C does not detect the detection position 525 because the second work arm 31 is not in the second posture (ejectable posture). Therefore, no voltage is applied to each of the first switching valve 75 and the second switching valve 76, and the first switching valve 75 is brought to the no-load position 752, which is the respective return position, and the second switching valve 76 is switched to the cutoff position 761.

(Position b indicating the device posture)
The relationship between the posture of the mowing device A, the hydraulic circuit, and the electric circuit in posture b indicating the device posture will be explained.
In posture b indicating the device posture, the mowing device A is in a state in which the sensor arms 51 (511, 512) have detected an obstacle W, as shown in FIG. The first working arm 21 is in contact with the second working arm 31. This shows a state in which the first working arm 21 and the second working arm 31 are in the first posture (acceptable posture), which is the normal working posture.

(Hydraulic circuit b)
In posture b indicating the device posture, the hydraulic circuit is hydraulic circuit b illustrated in FIG. The first control valve 75 is in the no-load position 752 and the second control valve is in the open position 762. The fluid pressure generated from the fluid pressure source 74 is returned to the storage tank 73 by the no-load position 752, and no pressure is applied to the actuator 14. The rod-side chamber 142 and the bottom-side chamber 143 of the actuator 14 are in communication with each other through the second switching valve 76 and the first control valve 75, allowing fluid to flow back and forth, and the rod 141 of the actuator 14 is in a freely retractable state. Become.

(Electric circuit b)
In posture a indicating the device posture, the electric circuit is in the electric circuit b state illustrated in FIG. The first sensor 52A is at the contact position 521 because the sensor arm 51 (511, 512) is pressed by the obstacle W and rotates. The second sensor 52B is in the closed position 524 because the first working arm 21 and the second working arm 31 are in close contact with each other. The third sensor 52C does not detect the detection position 525 because the second work arm 31 is not in the second posture (ejectable posture).
Since power is conducted to the second switching valve (control valve) 76 via the first sensor 52A located at the contact position 521 on the electric circuit, the second switching valve (control valve) 76 is switched to the open position 762. On the other hand, since no electricity is applied to the first switching valve 75, the first switching valve 75 is in the no-load position 752, which is the return position. Therefore, the actuator (cylinder) 14 is in a free expansion/contraction state (freely displaceable state) where no fluid pressure is applied, and the first arm 21 is rotated rearward due to the pressure of the obstacle W on the first arm 21 as the aircraft advances. can be done.

(Posture c indicating the device attitude)
The relationship between the posture of the mowing device A, the hydraulic circuit, and the electric circuit in posture c indicating the device posture will be explained.
In the posture c indicating the device posture, the mowing device A is in a state where the sensor arms 51 (511, 512) have detected an obstacle W, as shown in FIG. Since the obstacle W is sandwiched between the first working arm 21 and the second working arm 31, the first working arm 21 is separated from the second working arm 31. This shows a state in which the first working arm 21 and the second working arm 31 are in the middle of rotation after being shifted from the first posture (acceptable posture), which is a normal working posture, to the second posture (dischargeable posture). The switching valve (control valve) is switched according to the detection by the sensor, and the first working arm 21 and the second working arm 31 are in a rotatable state.

(Hydraulic circuit b)
In posture c indicating the device posture, the hydraulic circuit is hydraulic circuit b illustrated in FIG. The first control valve 75 is in the no-load position 752 and the second control valve is in the open position 762. The details of the hydraulic circuit b are as described in the above (hydraulic circuit b), so repeated explanation will be omitted.

(Electrical circuit c)
In posture c indicating the device posture, the electrical circuit is in the electrical circuit c state illustrated in FIG. The first sensor 52A is at the contact position 521. The second sensor 52B is in the open position 523 because the first working arm 21 and the second working arm 31 are relatively open with the obstacle W in between. The third sensor 52C detects the detection position 525 because the second work arm 31 pinches the obstacle W between the first work arms 21 and rotates horizontally to the rear side to take the second posture (ejectable posture). are doing. In the electric circuit, power is conducted to the second switching valve (control valve) 76 via the contact position 521 of the first sensor 52A, and the second switching valve (control valve) 76 is switched to the open position 762. On the other hand, since no voltage is applied to the first switching valve 75, it is in a no-load position 752. Therefore, the actuator (cylinder) 14 is in a free expansion/contraction state (displaceable state) where no fluid pressure is applied, and following the above posture b and the states of the hydraulic circuit b and the electric circuit b, the first arm 21 is pressed by the obstacle W. can continue to rotate toward the rear.

(Posture d indicating the device attitude)
The relationship between the posture of the mowing device A, the hydraulic circuit, and the electric circuit in the posture d indicating the device posture will be explained.
In posture d indicating the device posture, the mowing device A is in a state where the first working arm 21 and the second working arm 31 are in the second posture, as shown in FIG. 7, and the sensor arms 51 (511, 512) represents a state in which the obstacle W is not detected (this is a case where the obstacle W is separated from the sensor arm 51 (511, 512) when the first working arm 21 is rotationally driven). The obstacle W is sandwiched between the first working arm 21 and the second working arm 31, and the first working arm 21 is separated from the second working arm 31.
The first working arm 21 and the second working arm 31 are in the middle of rotating from the first posture (acceptable posture), which is a normal working posture, to the second posture (dischargeable posture).

(Hydraulic circuit b)
In posture d indicating the device posture, the hydraulic circuit is hydraulic circuit b illustrated in FIG. 10 . The first control valve 75 is in the no-load position 752 and the second control valve is in the open position 762. The details of the hydraulic circuit b are as described in the above (hydraulic circuit b), so repeated explanation will be omitted.

(electric circuit d)
In posture d, which represents the device posture, the electrical circuit is electrical circuit d illustrated in FIG. Since the obstacle W is away from the sensor arm 51, the first sensor 52A is at the non-contact position 522. The second sensor 52B is in the open position 523 since the first working arm 21 and the second working arm 31 are in an open state. The third sensor 52C detects the detection position 525 because the second work arm 31 is in the second posture (ejectable posture).
Since the second switching valve (control valve) 76 is electrically connected via the first sensor 52A and the second sensor 52C, the second switching valve (control valve) 76 is in the open position 762. Therefore, the actuator (cylinder) 14 is in a free expansion/contraction state (freely displaceable state).

In the case of the illustrated posture d, the obstacle W is in a state away from the sensor arm 51 and the first working arm 21, and the first working arm 21 is not pressed rearward, so the actuator 14 in the freely extendable state does not extend or contract. When the sensor arm 51 and the first working arm 21 are pushed again by the obstacle W as the aircraft moves forward, the position c becomes the above-mentioned state, and the first working arm 21 rotates backward. Therefore, in the second posture, even if the state of posture c and posture e are alternately repeated due to the contact state between the obstacle W, the sensor arm 51, and the first work arm 21, the actuator 14 is externally connected to the rod 141. The first working arm 21 will not expand or contract unless the obstacle W exerts a force that causes the first working arm 21 to rotate. That is, when the sensor arm 51 is pushed by the obstacle W, or when the first work arm 21 is in the second posture and the first work arm 21 and the second work arm 31 are relatively open. Since the second switching valve (control valve) 76 is in the open position 762, the first working arm 21 can freely rotate horizontally regardless of the fluid pressure.

(Posture e indicating the device attitude)
The relationship between the posture of the mowing device A, the hydraulic circuit, and the electric circuit in posture e indicating the device posture will be explained.
In posture e indicating the device posture of the mowing device A, as shown in FIG. 8, the sensor arms 51 (511, 512) are not detecting the obstacle W. The first working arm 21 is in contact with the second working arm 31.
Both the first work arm 21 and the second work arm 31 are in a state of being rotated toward the second position (ejectable position). In other words, after the distal ends of the first working arm 21 and the second working arm 31 sandwiching the obstacle W are both rotated backwards in the second posture (ejectable posture), the obstacle W is removed from the first working arm 21 and the second working arm 31. The first working arm 21 and the second working arm 31 are in a closed state after being separated from the second working arm 31 after being discharged.

(Hydraulic circuit c)
In posture e indicating the device posture, the hydraulic circuit is hydraulic circuit c illustrated in FIG. 11 . The first control valve 75 is in the pumping position 751 and the second control valve 76 is in the blocking position 761. The fluid pressure generated from the fluid pressure generation source 74 is forced to be sent to the second switching valve 76 by the pumping position 751 via the sending pipe line 71a and the sending pipe line 71b. Since the feed line 71a and the feed line 71b at the pressure feeding position 751 are not in communication with the return line 72a and the return line 72b, the fluid is not returned to the storage tank 73. In other words, the upstream and downstream sides of the fluid are separate circuits. Due to the blocking position 761 in which the second control valve 76 is a check circuit, the fluid pressure sent from the fluid pressure generation source 74 side is sent to the bottom side chamber 143 of the actuator 14 on the downstream side without being blocked. The fluid in the rod side chamber 142 returns to the storage tank 73 via the return line 72a, the first control valve 75, and the return line 72b further downstream. Therefore, the rod 141 of the actuator 14 protrudes, allowing the actuator 14 to extend.

(Electrical circuit e)
The electric circuit in posture e indicating the device posture is electric circuit e illustrated in FIG.
The first sensor 52A is in a non-contact position 522 because the sensor arm 51 (511, 512) is not pressed by the obstacle W. The second sensor 52B is in the closed position 524 because the first working arm 21 and the second working arm 31 are in close contact with each other. The third sensor 52C detects the detection position 525 because the second work arm 31 is in the second posture (ejectable posture).
In the electric circuit e, the first switching valve 75 is switched to the pumping position 751 by making the first switching valve 75 conductive and applying voltage via the first sensor 52A to the third sensor. Since the second switching valve 76 is disconnected from the first switching valve 75, it is returned to the cutoff position 761 without electrical application.
The actuator (cylinder) 14 is driven to the extension side, and the first working arm 21 and the second working arm 31 are returned to the first posture (acceptable posture).

The operation of the mowing device A will be explained. As shown in FIGS. 1 to 8, the mowing device A is pushed or pulled forward in the traveling direction by the traveling body and is driven to mow the grass. During the work, an obstacle W may exist.
Since the first elastic body 41 biases the second work arm 31 in a direction toward the first work arm 21, the first work arm 21 and the second work arm 31 are brought close to each other, and the tip portion between them is is closed. Further, the first working arm 21 has its distal end directed forward by the operating means 14 . At the same time, the second working arm 31 is pushed by the first working arm 21 and is directed forward against the urging force of the second elastic body 42 . Therefore, the first working arm 21 and the second working arm 31 are in an acceptable posture (first posture).

(Position a indicating the device posture)
In a normal mowing work state, as shown in FIGS. 1 and 4, the first elastic body 41 that biases the second work arm 31 in a direction toward the first work arm 21 is stretched. At this time, the rod 141 of the operating means 14 is in an extended state.
The sensor arms 51 (first sensor arm 511, second sensor arm 512) are not in contact with the obstacle W and are not sensing the obstacle W.
The first work arm 21, the second work arm 31, and the sensor arm 51 take such a state of facing forward in the direction of travel and become an acceptable posture (first posture), and the traveling machine moves the mowing device A toward the front in the direction of travel. move it forward. The electric circuit at this time is the electric circuit a shown in FIG. 9, which forms the hydraulic circuit b.

When the mowing device A encounters an obstacle W while the mowing device A is moving, the obstacle W comes into contact with the second work arm 31 as shown in FIGS. 4 to 8.

(Position b indicating the device posture)
FIG. 5 shows the moment when the obstacle W and the second work arm 31 come into contact. In the case of the embodiment of the present invention illustrated in FIG. It is shown in a state where it is located between the arranged hydraulic motors 342 and in contact with the tips of the first working arm 21 and the second working arm 31. Furthermore, the obstacle W is pressing the sensor arm 51, and the first sensor 52A is in a state of detecting that the obstacle W has contacted the first working arm 21.

If the traveling aircraft comes into contact with an obstacle W while moving from the state shown in FIG. 4, it will become the state shown in FIG. 5.
As shown in FIG. 5, the obstacle W comes into contact with the first work arm 21, and the obstacle W contacts and is sensed by the sensor arm 51, causing the sensor arm 51 to rotate backward. The first sensor 52A installed at the rear of the sensor arm 51 is pushed to bring it into the detection state where the electric circuit is switched to the contact position 521. That is, the electric circuit becomes the electric circuit b shown in FIG. 13, and the hydraulic circuit forms the hydraulic circuit b shown in FIG.

When the first sensor 52A takes the electric circuit b in the detection state, the second switching valve 76, which is a solenoid valve of the hydraulic control valve of the operating means 14, is operated to the open position 762 side to form the hydraulic circuit b, and the operating means 14 rods 141 are brought into a state where they can be shortened. In addition, since the first switching valve 75 in this case remains in the no-load position 752, the first working arm 21 is in a freely rotatable state. The sensor arm 51 is used to control a series of operations up to the time when the rod 141 is driven to shorten.

(Posture c indicating the device attitude)
When the traveling aircraft continues to travel from the state shown in FIG. 5, it enters the state shown in FIG. 6.
In the state shown in FIG. 6, the first work arm 21 is opened outward by the pressure of the obstacle W caused by the traveling body, and the obstacle W is positioned between the first work arm 21 and the second work arm 31. The state will be as follows. The obstacle W represented by the two-dot chain line in FIG. 6 is at a position where the traveling machine advances and further moves relative to the contact portion 23 side, and the first work arm rotates rearward due to the pressure of the obstacle W. It is in the process of being done. The second working arm 31 has shifted to a second posture in which it has rotated to follow the first working arm 21.

When the obstacle W presses the sensor arm 51 and enters between the first work arm 21 and the second work arm 31, the obstacle W causes each of the first sensor 52A, the second sensor 52B, and the third sensor 52C to The detection state is entered, and the rod 141 of the operating means 14 is brought into a state where it can be shortened. Then, as shown in FIG. 6, the first working arm 21 turns rearward, which is the direction away from the second working arm 21, about the turning axis 12.
At this time, the second elastic body 42 performs a shortening operation, so that the repulsive force is further increased compared to when the second elastic body 42 is in the acceptable posture (first posture). As shown in FIG. 6, when the obstacle W moves relatively to the vicinity of the contact portion 23, the second working arm 31 is pivoted toward the first working arm 21 by the second elastic body 42. As shown in FIG. Therefore, the obstacle W is in contact with and sandwiched between the first work arm and the second work arm. That is, the electric circuit forms an electric circuit c shown in FIG. 14, and the hydraulic circuit forms a hydraulic circuit b shown in FIG.
Since the rod 141 of the operating means 14 is in a freely extendable state, the first working arm 21 and the second working arm 31 connected to the first working arm 21 can be moved around the obstacle W. The arm is passively rotated by contact to prevent damage caused by the arm colliding with the obstacle W.

As shown in FIG. 6, since the second elastic body 42 brings the obstacle W into contact between the first work arm 21 and the second work arm 31, the mower blades 241 and 341 can be used around the obstacle W. You can cut as close to the area as possible.
While the obstacle W is passing between the cutting blades 241 and 341 of the first working arm 21 and the second working arm 31, the obstacle W can be efficiently sent to the contact portion 23 or near the pivot axis 12. I can do it.
Thereafter, the obstacle W is relatively moved toward the pivot shaft 12, which is the rotation fulcrum of the first work arm 21 and the second work arm 31.

As shown in FIG. 6, the mowing device A further advances with the obstacle W sandwiched between the first working arm 21 and the second working arm 31. Then, the obstacle W comes into contact with the contact portion 23 and the sensor arm 51 (first sensor arm 511, second sensor arm 512). At the same time, the obstacle W continues to move toward the pivot shaft 12 and then presses the contact portion 23 . Due to the pressure of the sensor arm 51, the first sensor 52A enters the detection state, and the first working arm 21 presses the contact portion 23 due to the obstacle W, so that it rotates about the pivot shaft 12. The second working arm 31 connected to the first working arm 21 can also rotate in conjunction with the first working arm 21 due to the increased repulsive force of the second elastic body 42 .

The traveling machine and the mowing device A move further. When the rod 141 of the operating means 14 further contracts as the traveling aircraft advances, the first working arm 21 further rotates rearward about the pivot shaft 12.
The second working arm 31 is connected to the first working arm 21 which can be driven to swing, so it turns in conjunction with the first working arm 21. Further, the second work arm 31 is rotatable separately from the first work arm 21, but is biased toward the first work arm 21 by the second elastic body 42, so that the obstacle W is and rotates while pinching near the contact portion 23.
Then, the tips of the first working arm 21 and the second working arm 31 of the mowing device A that have come into contact with the obstacle W face toward the rear.

(Posture d indicating the device attitude)
From the state shown in FIG. 6, the traveling body changes its traveling speed and travels, or the first work arm 21 and the second work arm 31 further inhibit the rotation, so that the rotation is properly performed. If not, the state shown in FIG. 7 may occur. This state represents a state in which the first work arm 21 and the second work arm 31 are in an ejectable posture (second posture), a state in which the pressure on the sensor arm 51 by the obstacle W is released, and a state in which the first work arm 21 is This is a state in which the second working arm 31 is rotated in the opening direction. That is, the electric circuit forms an electric circuit d shown in FIG. 15, and the hydraulic circuit forms a hydraulic circuit b shown in FIG. Although the conduction path of the electric circuit d is changed compared to the cases of postures b and c, the hydraulic circuit is unchanged from the cases of postures b and c, so the first working arm 21 continues to be freely moved. It is in a state where it can be rotated. Hydraulic circuit configuration in which when the first working arm 21 is in the second posture and in a relatively open state with respect to the second working arm, the operating means 14 is in the driving state even if the pressure on the sensor arm 51 is released. Not. Therefore, the obstacle W and the mowing device A will not be damaged due to unexpected movements.

(Posture e indicating the device attitude)
If the traveling aircraft continues to advance from the state shown in FIGS. 6 and 7, it will enter the state shown in FIG. 8.
As shown in FIG. 8, as the traveling machine moves forward, the obstacle W relatively leaves the contact portion 23 facing the rear side, and the first work arm 21 and the second work arm 31 face the rear side. towards the tip. Eventually, the obstacle W separates from the tips of the first working arm 21 and the second working arm 31 to the rear side.

In the ejectable posture (second posture) shown in FIG. 8, the obstacle W separates from the first working arm 21 and the second working arm 31 as the traveling machine moves forward. At the time of detachment, the obstacle W pushes away the second working arm 31 and moves relatively to the rear side. Since the second working arm 31 is urged by the second elastic body 42, after the obstacle W pushes the second working arm 31 away, it rotates toward the first working arm 21 again.

When the obstacle W separates from the first working arm 21 and the second working arm 31, the sensor arm 51 does not come into contact with the obstacle W, and therefore does not sense the obstacle W. Since the first working arm 21 and the second working arm 31 do not sandwich the obstacle W, they are in close contact with each other.
When the sensor arm 51 no longer senses the obstacle W in the ejectable posture (second posture) and the first work arm 21 and the second work arm 31 close each other, the first sensor 52A moves to the non-contact position 522. Since the second sensor 52B takes the closed position 524, the electric circuit becomes the electric circuit e shown in FIG. The electric circuit e causes the hydraulic circuit to form the state of the hydraulic circuit c shown in FIG. 11 and causes the rod 141 of the operating means 14 to extend. Then, the first working arm 21 returns to the first posture, which is the acceptable posture of the original position with the tip facing forward.
Due to the elastic force of the second elastic body 42, the second working arm 31 also moves along with the rotating first working arm 21 and returns to the first posture.

(1) The effects of the hydraulic circuit will be explained.
As shown in FIG. 10, when the first switching valve (control valve) 75 is in the no-load position 752, the first switching valve (control valve) 75 is connected to the circuit on the pump (fluid pressure generation source) 74 side and the tank 73 side. is in communication with the circuit. Further, the first switching valve (control valve) 75 and the circuit (feed lines 71b, 71c) communicating with the rod side chamber 142 of the actuator (cylinder) 14 are in a communicating state.
That is, the circuit (return pipes 72a, 72b) leading to the rod-side chamber 142 of the actuator (cylinder) 14 is in communication with the pump 74 side and the tank 73 side. Therefore, the fluid pressure sent from the pump 74 is returned to the tank 73 side without applying pressure to the rod side circuit 142 of the actuator 14. Furthermore, since the fluid pressure generated by the pump 74 is returned to the tank 73 side without being forcibly stopped, a control valve or the like is installed in the circuit between the first switching valve (control valve) 75, the pump 74, and the tank 73. No need to add.

(2) In the embodiment of the present invention, the pump 74 is constantly driven by the power from the traveling aircraft, so there is no need to switch this power or switch the fluid pressure generated by the pump 74. That is, while the fluid pressure generation source (pump) 74 and the fluid storage tank (oil tank) 73 are common, the sending side pipes (71b, 71c) and the return side pipes (72b, 72c) are made as simple as possible. As for the configuration, the entire device can be made as simple as possible.

(3) As shown in FIG. 9, when the first switching valve (control valve) 75 is in the no-load position 752 and the second switching valve (control valve) 76 is further switched to the cutoff position 761, The flow of fluid from the bottom chamber 143 of the actuator (cylinder) 14 toward the first switching valve (control valve) 75 is stopped. Therefore, the actuator 14 can maintain its current extended and contracted position without being shortened. That is, the first posture (acceptable posture), which is the posture during normal work, is maintained.

(4) As shown in FIG. 10, when the first switching valve (control valve) 75 is in the no-load position 752 and when the second switching valve (control valve) 76 is switched to the open position 762, the bottom The fluid flowing toward the side chamber 143 and the first switching valve (control valve) 75 can freely flow back and forth. That is, the rod-side chamber 142 of the actuator (cylinder) 14 and the bottom-side chamber 143 of the actuator (cylinder) 14 are in communication with the tank 73 .

Further, the first switching valve (control valve) 75 at the no-load position 752 brings the rod side chamber 142 and the bottom side chamber 143 of the actuator (cylinder) 14 into communication. Therefore, the fluid pressure fed from the pump 74 is returned to the tank 73 and no pressure is applied to the actuator 14. Further, the rod 141 can be freely extended and contracted, and the first working arm 21 is moved passively from the receptive position (first position) to the ejectable position (second position) by the pressure of the obstacle W. (rotation of the first working arm 21 in the direction of the ejectable posture (second posture) due to an obstacle).

(5) As shown in FIG. 11, when the first switching valve (control valve) 75 is in the pumping position 751, the first switching valve (control valve) 75 is connected to the pump 74 side circuit (71a, 71b, 71c). and the bottom side chamber 143 of the actuator (cylinder) 14 are brought into communication, and the rod side chamber 142 of the actuator (cylinder) 14 and the circuits (72a, 72b) on the tank 73 side are brought into communication, respectively.
Therefore, the fluid pressure sent from the pump 74 is sent to the bottom side 143 circuits (71a, 71b, 71c) of the actuator 14, and the rod 141 of the actuator 14 can be extended. The fluid in the rod side 142 circuit (72a, 72b) of the actuator 14 is returned to the tank 73 side via the first switching valve (control valve) 75.

At this time, whether the switching position of the second switching valve (control valve) 76 is the blocking position 761 or the opening position 762 does not affect the driving of the extension operation of the actuator 14. Although the second switching valve (control valve) 76 in the embodiment of the present invention is switched to the blocking position 761, it does not obstruct the flow of fluid from the first switching valve (control valve) blocking position 75 toward the bottom side chamber 143. No (return operation from ejectable posture (second posture) to receptive posture (first posture)).

(6) As shown in FIG. 11, when the first switching valve (control valve) 75 is in the pressure feeding position 751, the second switching valve (control valve) 76 is switched to the cutoff position 761 because the first switching valve Electric circuits (details will be described later) that respectively switch two switching valves (control valves), a valve (control valve) 75 and a second switching valve (control valve) 76, are operated by three sensors (switches). This occurs because the relay circuit is configured. The operations (3) and (5) are realized with a simple configuration. (If the second switching valve (control valve) 76 is set to the open position 762 at the time of (5) shown in FIG. 11 above, a separate control device will be required and the configuration will not be simple.)

(7) Due to the configuration of the fluid pressure circuit according to the embodiment of the present invention, the first working arm 21 and the second working arm 31 can be rotated by only one actuator 14. That is, by installing a spring that is an elastic body, the second working arm 31 can rotate so as to follow the first working arm 21.

(8) By simply switching the first switching valve (control valve) 75, which has two switching positions, the actuator 14 can be switched between driving the actuator 14 in the extension direction and freely moving it in the extension and contraction direction.
Therefore, it is possible to easily switch between forced return of the first work arm 21 to the acceptable posture (first posture) and passive operation when an obstacle is caught.

(9) The circuit configuration is simplified because the shortening of the actuator 14 is prevented by simply blocking the outflow of pressure from the bottom chamber 143 of the actuator (cylinder) 14 at the blocking position 761 of the second switching valve (control valve) 76. can be converted into
(10) In order to switch the first switching valve (control valve) 75 and the second switching valve (control valve) 76, three sensors are used: the first sensor 52A, the second sensor 52B, and the third sensor 52C. By connecting these three sensors and two switching valves (control valves) through a relay circuit, the two switching valves (control valves) can operate without requiring a control device.

(11) The effects of the electric circuit will be explained.
The state of the electric circuit when the first working arm 21 and the second working arm 31 are in the acceptable posture (first posture), which is the normal working position, will be explained.
As shown in FIG. 12, the first sensor 52A is not in contact with the obstacle W or the like, so the circuit is switched to the non-contact position 522 and connected to the circuit leading to the second sensor 52B.

The second sensor 52B is in a state where the second working arm 31 and the first working arm 21 are closed, and the second working arm 31 and the first working arm 21 are in contact with each other, so the circuit is in the contact position ( The working arm is switched to the closed position 524) and connected to the circuit leading to the third sensor. The third sensor does not conduct because the second work arm 31 is in the acceptable posture (first posture) (detects that it is in the acceptable posture (first posture)).
Therefore, the first switching valve (control valve) 75 and the second switching valve (control valve) 76 are disconnected from the power supply (connected to both +12V and GND in the figure), and the switching valve is in its return position. The first switching valve (control valve) 75 is switched to the no-load position 752 and the second switching valve (control valve) 76 is switched to the cutoff position 761.

(12) The state of the electric circuit when the obstacle W comes into contact with the sensor arm 51 (first sensor arm 511, second sensor arm 512) provided in the first working arm 21 will be described.
As shown in FIG. 13, the first sensor 52A detects the sensor arm 51 that has rotated due to contact with an obstacle W, etc., switches the circuit to the contact position 521, and switches the circuit to the contact position 521, ) 76. Therefore, the second switching valve (control valve) 76 is connected to the power source and switched to the open position 762. Thereafter, the fluid circuit enters the state (4) shown in FIG. 10. Since the first switching valve (control valve) 75 is disconnected from the power source, it is in the no-load position 752, which is the return position.

(13) When the sensor arm 51 comes into contact with the obstacle W, the second work arm 31 and the first work arm 21 are in an open state, and the second work arm 31 is rotated to the ejectable posture (second posture). Let me explain what happens when you move.
In this state, as shown in FIG. 14, the second sensor 52B is switched to connect the circuit to the second switching valve (control valve) 76 side (the work arm is in the open position 523), and the third sensor is switched to the second switching valve (control valve) 76 side. 1 switching valve (control valve) 75 (detection position of second attitude). However, since the first sensor 52A contacts the contact position 521 and connects the power to the circuit leading to the second switching valve (control valve) 76, the second switching valve (control valve) 76 maintains the open position 762. do. On the other hand, since the first switching valve (control valve) 75 is disconnected from the power source, it is in the no-load position 752, which is the return position. The fluid circuit remains in state (4).

(14) The state of (10) above (in order to switch the first switching valve (control valve) 75 and the second switching valve (control valve) 76, the first sensor 52A, the second sensor 52B, and the third sensor 52C, Three sensors are used. These three sensors and two switching valves (control valves) are connected by a relay circuit), and the sensor arm 51 (first sensor arm 511, second The sensor arm 512) is in a non-contact state with the obstacle W, the second work arm 31 and the first work arm 21 are open, and the second work arm 31 is rotated to the ejectable posture (second posture). Let's explain what happens when you are in this situation.
As shown in FIG. 15, the first sensor 52A is not in contact with the obstacle W or the like, so the circuit is switched to the non-contact position 522 and connected to the circuit leading to the second sensor 52B.

Since the second work arm 31 and the first work arm 21 are in the open state, and the second work arm 31 is rotated toward the ejectable posture (second posture), the second sensor 52B is in a non-contact (work The arm detects the open position 523). Therefore, the second sensor 52B connected to the power source on the GND side has a circuit connected to the second switching valve (control valve) 76 side, and the second switching valve (control valve) 76 maintains the state connected to the power source. .

The fluid circuit can maintain the second switching valve (control valve) 76 in the open position 762. The third sensor detects that the second work arm 31 is not in an acceptable posture (first posture), and brings the first switching valve (control valve) 75 and the third sensor into a conductive state (detection of the second posture). position 525), the first switching valve (control valve) 75 is not electrically connected to the power supply, so it remains at the no-load position 752. Thereby, the fluid circuit can maintain state (4).

(15) The first work arm 21 and the second work arm 31 are in the ejectable posture (second posture), the obstacle W is away from the sensor arm, and the first sensor 52A does not detect contact with the obstacle; Also, a state in which the first working arm 21 and the second working arm 31 are closed will be explained.
That is, as shown in FIG. 8, after the first working arm 21 and the second working arm 31 sandwich the obstacle W, the obstacle W rotates as the aircraft advances, and then the obstacle W is separated from the first working arm 21. The state separated from the second working arm 31 will be explained.

As shown in FIG. 16, the first sensor 52A is not in contact with the obstacle W or the like, so the GND side power supply circuit is switched to the non-contact position 522 and connected to the circuit leading to the second sensor 52B. Since the second work arm 31 and the first work arm 21 are in contact with each other, the circuit is switched to the contact position (the work arm is in the closed position 524), and the power supply circuit on the GND side is connected to the circuit leading to the third sensor. do.

Since the second work arm 31 is in the ejectable posture (second posture), the third sensor is in a conductive state (detects that it is in the ejectable posture (second posture), second posture detection position 525). Therefore, the second switching valve (control valve) 76 is disconnected from the power supply and returns to the cutoff position 761, and the first switching valve (control valve) 75 is connected to the power supply (connected to both +12V and GND in the figure). ), it switches to the pumping position 751.
The fluid circuit is in the state (5) above, and the first working arm 21 and the second working arm 31 are rotationally driven to the acceptable posture (first posture).

The effects of the hydraulic circuit and the electric circuit will be explained.
(1) The bottom side chamber 143 of the actuator 14 is connected to a fluid pressure generation source (pump) 74 through feed lines 71a, 71b, and 71c, and the inside of the rod side chamber 142 of the actuator 14 is connected to the storage tank 7 through return lines 72a and 72b. is connected to. In addition, a second switching valve 76 is arranged in the feed pipes 71b and 71c. As shown in Fig. 8 (attitude e) and Fig. 16 (electric circuit e), when the second switching valve 76 is in the cutoff position 761, the fluid is prevented from moving from the bottom chamber 143 to the fluid pressure generation source 74 side. It has become.

(2) As shown in FIGS. 9 and 11, when the second switching valve 76 is in the cutoff position, the relief valve 77 is activated as the pressure in the feed pipes 71a, 71b, and 71c increases. This causes the fluid in the feed lines 71a, 71b, 71c to escape into the return lines 72a, 72b. In the embodiment of the present invention, the pressure increase in the feed pipes 71a, 71b, and 71c is caused by an obstacle W or the like coming into contact with the first working arm 21 or the second working arm 31 and forcing it toward the second posture. The situation is assumed to be That is, by pressing the rod 141 of the cylinder 14, which is the actuator 14, in the direction of shortening, the pressure in the feed pipes 71a, 71b, and 71c between the bottom side chamber 143 and the second switching valve 76 increases. Due to the increase in pressure, the relief valve 77 operates and releases the fluid (pressure) in the feed lines 71a, 71b, 71c to the return lines 72a, 72b.

(3) In the operating state of the relief valve 77, both the bottom side chamber 143 and the rod side chamber 142 of the actuator 14 are connected to the storage tank 73. Furthermore, since the bottom side chamber 143 is in communication with the rod side chamber 142, the actuator 14, which is a cylinder, is in a state where it can freely expand and contract (a state where it can be freely displaced). In light of the embodiment, the first work arm 21 or the second work arm 31 that is forcibly pressed toward the second posture can rotate toward the second posture without resisting the obstacle W. can. Therefore, damage to the mowing device A including the first working arm 21 or the second working arm 31 can be prevented.
Forcible pressing in this case refers to pressing when the sensors 52A, 52B, and 52C are not sensing and the switching valves 75 and 76 are not operating normally.

(4) As shown in FIG. 10 (hydraulic circuit b, attitude d, FIG. 7, electric circuit d, FIG. 15), the second switching valve 76 is in the open position, and the first switching valve 75 is in the no-load position. In this case, even if the pressure in the feed pipes 71a, 71b, 71c increases, the feed pipes 71a, 71b, 71c and the return pipes 72a, 72b are in communication within the first switching valve 75 in the no-load position. Therefore, the fluid in the sending pipes 71a, 71b, 71c is released into the return pipes 72a, 72b. Furthermore, since the bottom side chamber 143 is in communication with the rod side chamber 142, the actuator 14, which is a cylinder, is in a state where it can freely expand and contract (a state where it can be freely displaced) without operating the relief valve 77.
In light of the embodiment, the first working arm 21 or the second working arm 31 that is forcibly pressed toward the second posture can rotate toward the second posture without resisting the obstacle W. (In the example, the normal operating state in which the switching valves 75 and 76 are operated by detection by the sensors 52A, 52B, and 52C).

(5) However, even in the above normal operating state, if the pressure in the feed pipes 71a, 71b, 71c increases due to an abnormality such as the actuator 14 extending or retracting too quickly, the relief Valve 77 operates to prevent damage to circuits and equipment.
(6) As shown in FIG. 11 (hydraulic circuit c, posture e FIG. 8, electric circuit e FIG. 16), even if the first switching valve 75 is in the pressure feeding position, the feed pipes 71a, 71b, 71c When the fluid pressure inside increases, the relief valve 77 operates to release the pressure to the return circuit, regardless of the switching position of the second switching valve 76.

(7) The drive mechanism and buffer mechanism for each arm are realized while simplifying the circuit configuration for changing the drive state and non-drive state of the actuator 14.
(8) Although the actuator 14 in the embodiment has been described as a cylinder, a fluid pressure motor may be used to rotate the first working arm 21. Furthermore, the expansion and contraction movement of the actuator 14 as a cylinder and the rotation direction of the first working arm 21 are not necessarily limited to those illustrated.

In the embodiment of the present invention, it is sufficient that the first working arm 21 and the second working arm 31 have the same pivot axis 12 as their pivot axis.
In the present invention, the first working arm 21 is rotated in accordance with the expansion and contraction of the rod 141.
The second working arm 31 rotates along with the first working arm 21 while being cushioned by the second elastic body 42 .

In the embodiment of the present invention, the front side of the contact part 23 may form a closed part C in which the first working arm 21 and the second working arm 31 are closed.
While moving the traveling machine, the rod 141 of the operating means 14 expands and contracts to cause the first working arm 21 and the second working arm 31 to rotate around the obstacle W located inside the closed part C, and to move toward the obstacle W. Prevent damage caused by arm collision.
In the embodiment described, the sensor arm 51 is composed of two sensor arms, the first sensor arm 511 and the second sensor arm 512, but it may be composed of three or more sensor arms connected together. In this case, since the moving distance associated with rotation of the tip of each sensor arm can be shortened, further improvement in the detection accuracy of the switch can be expected.
In the diagram showing the electric circuit of the embodiment, +12V is shown to indicate the voltage, but the voltage is not limited to this and can be changed as appropriate depending on the voltage used. Furthermore, an electric circuit can be configured by replacing the + side and the GND side (- side), and changes can be made as appropriate according to the specifications of the equipment used.

11 Base member 111 First base member 112 Second base member 12 Rotating shaft 13 Arm 13A Front arm 13B Rear arm 14 Operating means (actuator, cylinder)
15 Stopper 21 First work arm 22 Rotation regulating means guide (swing regulating means)
23 Contact part 24 First cutting blade part (cutting blade, cutting blade part, working part)
31 Second work arm 32 Rotation regulating protrusion (swing regulating means)
34 Second cutting blade part (cutting blade, cutting blade part, working part)
41 First elastic body 42 Second elastic body 5 Detection unit 51 Sensor arm 511 First sensor arm 511a First sensor arm pivot shaft 512 Second sensor arm 512a Second sensor arm pivot shaft 52A First sensor 52B Second sensor 52C Third sensor 53A Contact portion 53B Contact portion 53C Contact portion 71a Feed line 71b Feed line 71c Feed line 72a Return line 72b Return line 73 Tank 74 Fluid pressure source (pump)
75 First switching valve (first control valve)
751 Pressure feeding position 752 No-load position 76 Second switching valve (second control valve)
761 Shutoff position 762 Open position 77 Relief valve A Grass cutting device S Working machine W Obstacle

Claims (9)

a first work arm that is rotatable about a pivot axis;
a second work arm provided separately from the first work arm and pivotable about the pivot axis;
The first working arm and the second working arm change from a first posture in which the distal ends of the first working arm and the second working arm are facing forward to the second posture other than the first posture. The first working arm and the second working arm are pivotable between a second posture that is a posture state until the second working arm completely faces backward,
an actuator for rotating the first working arm;
a first switching valve that can be switched to a pressure-feeding position in which fluid is force-fed to the actuator and a no-load position in which fluid is not force-fed to the actuator;
A blocking position is disposed between the actuator and the first switching valve and blocks fluid from flowing from the actuator to the first switching valve, and a blocking position prevents fluid from flowing in and out between the actuator and the first switching valve. a second switching valve that can be switched to a freely open position;
a first sensor that detects that an obstacle has contacted the first work arm;
a second sensor that detects contact of the first work arm with the second work arm;
a third sensor that detects that the first work arm is in the first posture;
A grass cutting device comprising: If only the first sensor detects the detection, or if all of the first sensor, second sensor, and third sensor detect the detection, the first switching valve is switched to the no-load position, and the second switching valve is switched to the open position. switch to,
The mowing device according to claim 1, characterized in that: When only the second sensor detects the detection, switching the first switching valve to the pressure feeding position and switching the second switching valve to the blocking position;
The grass cutting device according to claim 1 or 2, characterized in that: When detected by the second sensor and the third sensor, switching the first switching valve to the no-load position and switching the second switching valve to the cutoff position;
The mowing device according to any one of claims 1, 2, and 3, characterized in that: When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture a indicating the device posture,
The first working arm and the second working arm are in the first posture, which is the normal working posture, facing forward in the direction of travel, and the sensor arm that detects obstacles ahead in the direction of travel is not detecting any obstacles. , the first working arm is in contact with the second working arm,
The hydraulic circuit is
The hydraulic circuit is in the a state. In the hydraulic circuit a state, the first switching valve is in the no-load position, the second control valve is in the cutoff position, the first switching valve and the second switching valve are not conductive, and the actuator shrink and regulate
When the second sensor detects that the first working arm has contacted the second working arm and the third sensor detects that the first working arm is in the first posture, the first switching valve is set to the no-load position. At the same time, switch the second switching valve to the cutoff position,
The electrical circuit is
The electric circuit is in the a state, and in the electric circuit a state, the first sensor for detecting that an obstacle has contacted the first working arm is in the non-contact position, and the second sensor is in the non-contact position. The work arm is in the closed position and the third sensor is not detecting the detection position 525 in the second posture.
The mowing device according to any one of claims 1, 2, 3, and 4. When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture b indicating the device posture,
The sensor arm has detected an obstacle, the first working arm is in contact with the second working arm, and the first working arm and the second working arm are in the first posture, which is the normal working posture. can be,
The hydraulic circuit is
The hydraulic circuit is in a state B, and in the state B, the first control valve is in a no-load position, the second control valve is in an open position,
The electrical circuit is
The electric circuit is in state b, and in the electric circuit b state, the first sensor is in the contact position, the second sensor is in the first working arm, the second working arm is in the closed position, and the third sensor is in the second position. The detection position is not detected,
6. The mowing device according to claim 1, wherein the second switching valve is made conductive via the first sensor, and the actuator is in a freely expanding and contracting state. When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture c indicating the device posture,
From the first posture in which the sensor arm has detected an obstacle, the first working arm is separated from the second working arm, and the first working arm and the second working arm are in the normal working posture, The first work arm and the second work arm are in the middle of rotation toward the second posture, and the first work arm and the second work arm are in a freely rotatable state by switching the switching valve based on detection by the sensor.
The hydraulic circuit is
The hydraulic circuit is in state B, and in the state of hydraulic circuit B, the first control valve is in the no-load position, the second control valve is in the open position, and only the first sensor 52A detects, or the first sensor and When both the second sensor and the third sensor detect the detection, the first switching valve is switched to the no-load position, and the second switching valve is switched to the open position;
The electrical circuit is
The electric circuit is in the C state, and in the electric circuit C state, the first sensor is in the contact position, the second sensor is in the first working arm, the second working arm is in the open position, and the third sensor is in the second position. Claim 1 or 2 or 3 or 4 or 5 or 5, wherein the detection position is detected, the second switching valve is made conductive via the first sensor, and the actuator is in a free expansion/contraction state (freely displaceable state). 6. The mowing device according to any one of 6. When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture d indicating the device posture,
the sensor arm is not detecting an obstacle, and the first work arm is separated from the second work arm;
The first working arm and the second working arm are in the middle of rotating from the first posture, which is a normal working posture, toward the second posture,
The hydraulic circuit is
Hydraulic circuit B is in state B, in which the first control valve is in the no-load position, the second control valve is in the open position,
The electrical circuit is
The electric circuit is in the d state, and in the electric circuit d state, the first sensor is in the non-contact position, the second sensor is in the first working arm, the second working arm is in the closed position, and the third sensor is in the second posture. The detection position of
8. The second switching valve is electrically connected via the first sensor and the second sensor, and the actuator is in a freely expanding and contracting state. Grass cutting equipment. When the mowing device comes into contact with an obstacle while moving, the mowing device sequentially adopts postures from posture a indicating the device posture to posture e indicating the device posture,
In posture e indicating the device posture,
The sensor arm is not detecting an obstacle, and the first work arm is in contact with the second work arm,
Both the first work arm and the second work arm are in a state of being rotated to the second posture side, and after the first work arm and the second work arm are rotated to the second posture side, the obstacle W is located between the first work arm and the second work arm. It is separated from the second working arm,
The hydraulic circuit is
Hydraulic circuit C is in state C, in hydraulic circuit C, the first control valve is in the pressure feeding position, the second control valve is in the cutoff position, and when only the second sensor detects, the first switching valve is switched to the pressure feeding position and , switch the second switching valve to the cutoff position,
The electrical circuit is
The electric circuit is in the e state, and in the electric circuit e state, the first sensor is in the non-contact position, the second sensor is in the first working arm and the second working arm are in the closed position, and the third sensor is in the second posture. The detection position of
energizing the first switching valve via the first sensor to the third sensor;
Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8, characterized in that the actuator is driven to the extension side and the first working arm and the second working arm are returned to the first posture. The grass cutting equipment described.

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