JP3218271B2 - Power transmission mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism which includes a fixed portion and a tilting portion based on the fixed portion, and transmits a driving force of a motor provided on the fixed portion side to the tilting portion side.
Is what you do. The present invention is preferably applied to, for example, a mower that includes a rotary blade on the tilting portion side and drives the rotary blade by the prime mover on the fixed portion side.
Things .

[0002]

2. Description of the Related Art As a mowing machine for ridges, there are a flat cutting blade that rotates along the upper surface of a ridge that is almost horizontal, and a slope cutting blade that rotates along a slope of a ridge that is almost downward inclined. 2. Description of the Related Art There is known a system in which both cutting blades are rotationally driven by the power of a motor mounted on an airframe.

In such a lawn mower, the outside of the slope cutting blade is tiltable up and down. This is to make it possible to make the inclination angle of the slope cutting blade correspond to the slope of the ridge having various inclination angles each time.

[0004]

However, the tilt
When the moving part is not used, tilt the tilting part upward
When power is transmitted to the slope cutting blade side also when
It is extremely dangerous to rotate the slope cutting blade while it is exposed.
You.

[0005] The present invention has been made in view of the above circumstances.
The tilting portion is at a predetermined tilt angle or more with respect to the fixed portion (for example, in the case of the mower, a large upward tilt angle at which the slope cutting blade is exposed).
When Tsu, automatically incapable allowed to power transmission to the tilting part side from the fixed portion side of the prime mover, safe power
It is intended to provide a transmission mechanism.

[0006]

Means for Solving the Problems To solve the above problems,
Therefore, the power transmission mechanism according to the first aspect of the present invention is fixed.
A fixed portion and a tilting portion based on the fixed portion,
The driving force of the prime mover provided on the fixed portion side is
Side, the tilting portion having a predetermined tilt
When the angle is greater than or equal to or less than the predetermined inclination angle
Tilt angle detection hand that operates in response to the tilt motion
And driving force transmission from the prime mover to the tilting portion side.
Shift lever to be controlled and drive force transmission of the shift lever
Lever path opening / closing means for opening and closing the movement path to the shift state
And wherein the tilt portion is equal to or greater than the predetermined tilt angle.
The lever path opening / closing means moves the lever.
Closing the moving path, and the tilting portion
The lever path opening / closing means moves forward when
The inclination angle detection means is set so as to open the movement path of the lever.
A step and the lever path opening / closing means are operatively connected.
is there.

A power transmission according to the present invention according to claim 2.
2. The shift lever according to claim 1, wherein
-The path of movement is formed by the lever guide member.
And the lever is held in the driving force transmission shift state.
A lever retaining recess is formed in the lever guide member, and
Push the bar out of the lever retaining recess in the direction
-When the path opening / closing means operates, the lever is moved.
The movement path is closed.

[0008]

According to the first aspect of the present invention, when the tilting portion is set to a predetermined tilt angle or more (for example, when the tilt portion is largely tilted upward or downward), the tilt angle detecting means according to the tilt operation. Operates. With the operation of the detection means, the lever path opening / closing means closes the movement path of the shift lever to the driving force transmission shift state. As a result, the shift lever cannot move to the driving force transmission shift state, so that there is no danger that power is unexpectedly transmitted to the tilting portion side due to an operation error or the like.

On the other hand, if the tilt of the tilting portion is within the normal use range equal to or less than the predetermined tilt angle, the tilt angle detecting means operates in the opposite direction according to the tilting operation. With the operation of the detection means, the lever path opening / closing means opens the movement path of the shift lever which has been closed up to then. Therefore, the shift lever can be moved to the driving force transmission shift state.

[0010] According to the present invention described in claim 2 ,
The tilting portion while the shift lever is kept in the driving force transmission shift state (that is, the power is transmitted to the tilting portion side by holding the shift lever in the lever retaining recess of the lever guide member). Is tilted to the predetermined tilt angle or more, the lever path opening / closing means operates in a direction to push out the shift lever from the lever retaining recess to automatically close the moving path of the shift lever. For this reason, the driving force transmission shift state of the shift lever is released, power transmission to the tilting portion side is automatically cut off, and the shift lever cannot be moved to the driving force transmission shift state as it is. .

[0011]

An embodiment of the present invention will be described in detail with reference to the drawings.

First, the basic configuration of a mower as an example of a specific device provided with a power transmission mechanism according to the present embodiment will be outlined.

As shown in FIGS. 1 to 3, the body 13 of the mower according to the present embodiment includes a fixed portion A and a tilting portion B. The tilting portion B is supported on the side of the fixed portion A by a support shaft 26 (see FIG. 1) extending in the front-rear direction of the body 13, and can tilt up and down around the axis of the support shaft 26. It has become. In this specification, the term “fixed portion” is a concept for a tilting portion, and means a portion that is a basis of tilting of the tilting portion.

As shown in FIGS. 2 and 3, a longitudinal axis type air-cooled gasoline engine 1 is mounted as a motor on the fixed portion A side, and a guide wheel 2 is provided at a front portion and a drive rear wheel 3 is provided at a rear portion. Is provided. The driven rear wheel 3 is driven by the engine 1 to apply a propulsive force to the body 13. Further, an operation handle 4 is provided on the fixed portion A side, and the handle 4 extends in a bifurcated manner toward the rear obliquely upward of the body 13. Further, the fixed portion A
Side and between the guide wheel 2 and the driving rear wheel 3,
A plane cutting blade 5 which is a horizontal rotary blade is provided.

2 and 3, reference numeral 50 denotes the handle 4
A throttle lever of the engine 1 attached to the
Reference numeral 51 denotes a recoil starter of the engine 1.

On the other hand, the tilting portion B is mainly composed of a cover-shaped tilting housing 41 and a slope cutting blade 6 which is a rotary blade housed in the tilting housing 41. The tilt housing 41 is tiltably supported by the support shaft 26 on the side of the fixed portion A.
In response to the tilting of the tilting housing 41, the slope cutting blade 6 also tilts up and down about the support shaft 26.

A method of adjusting the tilt angle of the tilt housing 41 and specific means for fixing the tilt housing at a desired angle will be described with reference to FIGS. The tilt housing 41 is integrally provided with a tilt angle adjusting plate 45 on its upper surface. This adjustment plate 45
Has an appropriate number of adjustment holes 45a. It is preferable that these adjustment holes 45a be located on an arc centered on the support shaft 26 when viewed from the front-back direction of the machine body 13.

On the other hand, on the fixed portion A side of the body 13, an inclination angle adjusting pin 46 that can move in the front-rear direction of the body 13 is provided via a plate-like bracket 13 c parallel to the adjustment plate 45. Have been. The pin 46 penetrates forward through the bracket 13c and protrudes into the adjustment hole 45a of the adjustment plate 45. The pin 46 is constantly urged forward by a pin urging spring 46a so as to maintain a state of being inserted into the adjustment hole 45a.

In the illustrated mowing machine, the tilting housing 41 can be fixed so as to maintain a horizontal state, and can be fixed by changing the inclination angle stepwise upward, while being downwardly fixed. In the inclined state, it is not fixed but free up to about 60 degrees downward.

The fixed portion A of the tilt housing 41
When adjusting the inclination angle with respect to, the pin 46 is slid rearward of the body 13 against the urging force of the spring body 46a. As a result, the pin 46 comes out of the adjustment hole 45a, so that the tilt housing 41 can freely tilt about the support shaft 26.
Therefore, by grasping the gripping rod 47 provided on the tilt housing 41 and moving the tilt housing 41 upward or downward to a desired tilt angle, selecting a new adjustment hole 45a and releasing the pin 46, The pin 46 protrudes into a new adjustment hole 45a by the urging force of the spring body 46a. In this way, the tilt housing 41 is fixed so as to maintain a new tilt angle.

In FIG. 1, reference numeral 52 denotes an auxiliary wheel provided on the tilting housing 41. When the tilting housing 41 is set free downward, the auxiliary wheel 52 acts to support the tilting housing 41 according to the tilting state of the slope of the ridge (see FIG. 3). In FIG. 4, reference numeral 41a denotes a skirt made of rubber or the like provided on the outer side and the rear side of the tilt housing 41. The skirt 41a prevents the cut grass from scattering to the side and the rear of the machine body 13 (operator side) due to the rotation of the slope cutting blade 6.

The flat cutting blade 5 is rotated by the engine 1 together with or independently of the side cutting blade 6. The slope cutting blade 6 is positioned diagonally behind the plane cutting blade 5 (in the illustrated example, diagonally to the left as shown in FIG. 1). As shown in FIG. 1, the flat cutting blade 5 and the side cutting blade 6 prevent the uncut portion between them from being left uncut.
They overlap each other by a predetermined width X in the left-right direction.

The driving of the driving rear wheel 3 will be described with reference to FIG. The engine 1 is disposed with its output shaft 1a facing downward. A wheel drive pulley 7 is fixed to the output shaft 1a. On the other hand, a transmission pulley 8 is arranged near the driving rear wheel 3 with its support shaft directed vertically. The transmission pulley 8 is drivingly connected to the driving rear wheel 3 via a reduction gear 10. A wheel drive belt 9 is loosely wound between the transmission pulley 8 and the wheel drive pulley 7.

In FIG. 1, reference numeral 11 denotes a traveling clutch. The traveling clutch 11 has a swing lever 14. The swing lever 14 is pivotally connected to the body 13 by a pin 12 at a base end thereof. Links 16 and 17 are connected to the base end side of the swing lever 14. The link 17 is operatively connected to a traveling clutch lever 18 attached to the operation handle 4.

On the other hand, a tension roller 15 is provided at the swing end of the swing lever 14 so as to press the wheel drive belt 9 and apply a predetermined tension thereto.

In the above-described configuration, when the traveling clutch lever 18 is not pulled, the wheel drive belt 9 is loose, so that even if the engine 1 is started,
The rotation of the wheel drive pulley 7 is not transmitted to the transmission pulley 8. On the other hand, when the traveling clutch lever 18 is pulled after the start of the engine 1, the tension roller 15 comes into pressure contact with the wheel drive belt 9 via the links 17, 16 and the swing lever 14. As a result, a predetermined tension is applied to the wheel drive belt 9, and the wheel drive pulley 7 and the transmission pulley 8 are operatively connected. As a result, the driving rear wheel 3 is rotationally driven via the speed reduction device 10 so as to advance the body 13.

Next, from the engine 1 to the plane cutting blade 5
A driving force transmission system to the slope cutting blade 6 will be described.

FIG. 1 and FIG. 5 showing an enlarged part of FIG.
As shown in the figure, the output shaft 1a of the engine 1 has:
The cutting blade drive pulley 19 is fixed as a driving pulley. On the other hand, a first pulley 20 for a plane cutting blade is fixed to the rotating shaft 5a of the plane cutting blade 5. A first V-belt 21 for cutting blade drive (hereinafter, illustrated as a flat belt for simplicity of illustration) is loose between the first pulley 20 for flat cutting blade and the driving pulley 19 for cutting blade. It is wound.

Outside the first belt 21, a rotatable first tension roller 22 is disposed. The first tension roller 22 is connected to the first belt 2.
1 can be displaced in a direction in which a predetermined tension is applied by pressing against and a direction in which the tension is released.

A second pulley 27 for a flat cutting blade is fixed to the rotating shaft 5a of the flat cutting blade 5. Lateral side of the flat cutting blade second pulley 27 (left side of the machine body 13 in the illustrated example)
Is provided with a slope cutting blade pulley 28. The slope cutting blade pulley 28 is attached to the machine body 13 with its rotating shaft 28a directed vertically.

A second V-belt 29 for driving the cutting blade (hereinafter referred to as a flat belt for simplification of the drawing) is provided between the second pulley 27 for the flat cutting blade and the pulley 28 for the side cutting blade. Is loosely wound. Outside the second belt 29, a rotatable second tension roller 4 is provided.
8 are arranged. This second tension roller 48
Can be displaced in a direction in which the second belt 29 is brought into pressure contact with the second belt 29 to apply a tension and a direction in which the tension is released.

As shown in FIG. 1, a driving bevel gear 30 is provided at the upper end of the rotating shaft 28a of the pulley 28 for the slope cutting blade.
Is fixed. A driven bevel gear 32 fixed to the front end of the transmission shaft 31 meshes with the drive bevel gear 30. The transmission shaft 31 is connected to the tilt housing 4.
The body 13 is horizontally supported along the support shaft 26 in the front-rear direction of the body 13. At the rear end of the transmission shaft 31, an intermediate drive timing pulley 33 is provided.

The body 13 has a rectangular movable rod 34 extending in the left-right direction. The intermediate drive timing pulley 33 is housed inside the base end of the movable rod 34. The movable rod 34 is located above the front part of the slope cutting blade 6. The movable rod 34 is configured so that the outer end side thereof can freely swing up and down around the intermediate drive timing pulley 33 (see FIG. 3).

Inside the swinging end (outer end) of the movable rod 34, an intermediate driven timing pulley 35 having a front and rear support shaft 35a is accommodated. A timing belt 36 is wound between the intermediate driven timing pulley 35 and the intermediate drive timing pulley 33.

An outer end of the movable rod 34 is connected to a rectangular tubular connecting rod 37 extending inward (toward the fixed portion A). A drive timing pulley 38 is housed inside the outer end of the connecting rod 37. The drive timing pulley 38 is provided on a support shaft 35a common to the intermediate driven timing pulley 35. The connecting rod 37 is connected to a support shaft 35a of the drive timing pulley 38.
With its center as the center, its inner end can swing freely up and down.

A driven timing pulley 39 having a rotational shaft 42 in the front-rear direction is accommodated inside the swinging end (inner end) of the connecting rod 37. A timing belt 40 is wound between the driven timing pulley 39 and the drive timing pulley 38.

The rotating shaft 42 of the driven timing pulley 39 extends rearward from the swinging end of the connecting rod 37. A drive bevel gear 43 is fixed to the rear end of the rotating shaft 42. This bevel gear 43
The driven bevel gear 44 fixed to the upper end of the rotating shaft 6a of the slope cutting blade 6 is engaged with the driven bevel gear 44.

As described above, the tilt housing 4
1 can be tilted about the axis of the support shaft 26 and can be fixed so as to maintain a desired tilt angle. FIG. 9 shows a state where the tilt housing 41 is tilted as viewed from the rear of the body 13.

In FIG. 9, a first arc C1 is a locus drawn by the rotary shaft 42 when the tilt housing 41 tilts, and a second arc C2 is formed by the intermediate driven timing pulley 35 and the drive timing. This is a locus drawn by the common support shaft 35a with the pulley 38. The first arc C
Reference numeral 1 denotes an arc centered on the support shaft 26, and the second arc C2 is an arc centered on the transmission shaft 31.
Then, the connecting rod 37 moves between the second arc C2 and the first arc C1.

Now, the center of the transmission shaft 31 is P, the center of the common support shaft 35a is Q, the center of the rotary shaft 42 is R,
The center of the support shaft 26 is denoted by S. At this time, the connection of the tilting housing 41 to the fixed portion A is substantially performed by a limited chain using the line segment SP as a fixed link by four links indicated by line segments PQ, QR, RS, and SP. Has become.

As described above, the fixed portion A
A power transmission system from the rotation shaft 28a of the side surface cutting blade pulley 28 provided on the side to the side surface cutting blade 6 substantially exists along the link. Therefore, even if the tilt housing 41 is largely tilted up and down, the fixed portion A
There is no hindrance to the power transmission from the side to the slope cutting blade 6. Therefore, the tilting housing 41 is folded toward the fixed portion A as necessary, and only the upper surface of the narrow ridge is mowing using only the flat mowing blade 5, or the so-called upward slope is mowing. be able to.

Further, since the tilting housing 41 can be folded toward the fixed portion A to make the body 13 compact, it is convenient for transportation and storage.

Further, mowing work can be performed by changing the inclination angle of the tilt housing 41 in various ways.
Applicable to various terrain work sites.

Next, with reference to FIGS. 5 to 8, control means for controlling power transmission from the engine 1 to the plane cutting blade 5 and the slope cutting blade 6 will be described.

A vertical support shaft 60 is mounted on the body 13a.
Thereby, the operation lever 61 is rotatably mounted. The operating lever 61 is for operating the first tension roller 22 so as to press against the outer peripheral surface of the first belt 21.

Between the operating lever 61 and the first tension roller 22, there is provided a torsion coil spring-like roller pressing spring 64. The spring body 64 acts to transmit the rotational power of the operating lever 61 as a pressing force of the first tension roller 22 to the first belt 21.

The degree of the spring force of the spring body 64 depends on the rotational force of the operating lever 61 with respect to the first belt 21 until the first belt 21 has a predetermined tension suitable for power transmission. The force is transmitted as the pressure contact force of the first tension roller 22, but when the tension of the first belt 21 reaches a predetermined value, the force is not transmitted any more.

In the illustrated example, a first tension roller arm 62 is rotatably attached to the support shaft 60 of the operation lever 61 on the base end side thereof. On the tip end side of the first tension roller arm 62,
The first tension roller 22 is rotatably provided by a vertical support shaft 63.

The first tension roller arm 62
The torsion coil spring 64 that urges them in directions opposite to each other is provided as the spring body 64 between the and the operating lever 61. This coil spring 64
The first tension roller 22 constantly urges the first tension roller arm 62 in a direction in which the first tension roller 22 is pressed against the first belt 21 to apply tension. The coil spring 64 has its winding start end 64a hooked to the first tension roller arm 62, and its winding end 64b hooked to the operating lever 61, and the support shaft 60 of the operating lever 61. It is provided around.

The first tension roller arm 62
Has an extending portion 65 integrally extending upward toward the operating lever 61 side. The first tension roller arm 62 and the operating lever 61 are urged in opposite rotation directions by the coil spring 64, and are normally in contact with the extending portion 65 and the swing end 61a side of the operating lever 61. Are in contact with each other to be integrated with each other.

The front end 25a of the push-pull cable 25 for shift operation is connected to the operation end 61b side of the operation lever 61. The shift operation cable 25 extends rearward of the body 13 and has a rear end 2.
5b is connected to the shift lever 24.

As shown in FIGS. 2, 5 and 12, the shift lever 24 is supported by a shift lever guide member 24c attached to the operation handle 4 via a lever support shaft 4a. It is swingable in the front-rear direction along a shift lever guide groove 24d formed in 24c. A moving path of the shift lever 24 is formed by the guide groove 24d.
Is tilted to the rear of the machine body 13, the shift operation cable 25 is pulled rearward, and conversely, if the shift lever 24 is returned to the front, the operation cable 25 is returned to the front. In FIG. 12, reference numeral 24e denotes a lever return spring which constantly pulls the shift lever 24 forward.

The shift lever guide member 24c has a first-stage locking concave portion 24a and a second-stage locking concave portion 24b as lever retaining concave portions.
And are formed so as to be smoothly continuous. The shift lever 24 is provided with these locking recesses 24a, 2a.
4b, the lever return spring 2
It is stopped against the pulling force of 4e.

In the above configuration, when the engine 1 is started and the shift lever 24 is pulled to stop in the first-stage locking recess 24a, the shift operation cable 25 is pulled rearward. As a result, the operation end 61b side of the operation lever 61 is pulled backward (FIG. 5).
reference). Then, the operation lever 61 rotates around the support shaft 60, and the swing end 61a side rotates forward. The rotation of the operating lever 61 on the swing end 61 a side is transmitted to the first tension roller arm 62 via the coil spring 64, and the first tension roller 22 It is pressed against the outer peripheral surface.

As a result, a predetermined tension suitable for power transmission is applied to the first belt 21, and the cutting blade drive pulley 19 and the first pulley 20 for the plane cutting blade are operatively connected. Then, when the first pulley 20 for the plane cutting blade rotates, the plane cutting blade 5 rotates via the rotating shaft 5a.

In this embodiment, the shift lever 2
4 is further pulled rearward from the first-stage locking recess 24a and moved to the second-stage locking recess 24b, so that the slope cutting blade 6 in addition to the plane cutting blade 5 also starts rotating. It has become.

That is, as shown in FIGS. 5, 7 and 8, the second tension roller arm 67 is rotated near the operation lever 61 by the vertical support shaft 66 fixed to the body 13b. It is movably supported. As shown in FIG. 8, the second tension roller arm 67 is disposed so as to be shifted vertically from the operation lever 61. The second tension roller 48 is rotatably attached to the swing end 67a side of the second tension roller arm 67 by a vertical support shaft 68.

On the operation end 61b side of the operation lever 61, an extension 69 extending upward toward the second tension roller arm 67 is formed at a right angle. When the operating lever 61 rotates counterclockwise as viewed in FIG. 5, the extending portion 69 has a predetermined tension suitable for transmitting power to the first belt 21 by pressing the first tension roller 22. Is provided, the second tension roller arm 67 comes into contact with the operation end 67b side of the second tension roller arm 67. The extending portion 69 transmits the rotational force of the operating lever 61 to the second tension roller arm 6.
7 to rotate the arm 67.

In the above-described configuration, when the shift lever 24 is further pulled from the first-stage locking recess 24a to the second-stage locking recess 24b and moved, the operating lever 61 is further rotated. Move. However, since the magnitude of the spring force of the coil spring 64 is as described above, there is no significant change in the pressing force of the first tension roller 22 against the first belt 21. That is, there is no change in the degree of tension of the first belt 21,
The transmission of power to the flat blade 5 is not hindered.

When the operating lever 61 is further rotated by moving the shift lever 24 from the first-stage engaging recess 24a to the second-stage engaging recess 24b, the operation lever 61 While the extension portion 69 is in contact with the operation end 67b side of the second tension roller arm 67, they rotate integrally. That is, the turning force of the operating lever 61 is transmitted to the second tension roller arm 67 via the extending portion 69, and the arm 67 is rotated in the same direction as the operating lever 61. As a result, the second tension roller 48 comes into pressure contact with the outer peripheral surface of the second belt 29,
The second belt 29 reaches a predetermined tension suitable for power transmission.

When a predetermined tension suitable for transmitting power is applied to the second belt 29 as described above, the second pulley 27 for the plane cutting blade and the pulley 28 for the slope cutting blade operate. It is connected above. Therefore, the power of the engine 1 is transmitted to the side surface cutting blade pulley 28 via the rotation shaft 5a of the flat surface cutting blade 5.

When the slope cutting blade pulley 28 rotates,
In order, the drive bevel gear 30, the driven bevel gear 32, the transmission shaft 31, the intermediate drive timing pulley 33, the timing belt 36, the intermediate driven timing pulley 35, and the support shaft 35
a, drive timing pulley 38, timing belt 4
The rotation power is transmitted to the driven timing pulley 39, the rotating shaft 42, the driving bevel gear 43, and the driven bevel gear 44, and the slope cutting blade 6 is rotated in the same direction as the plane cutting blade 5.

When the shift lever 24 is disengaged from the second-stage locking recess 24b and returned to the first-stage locking recess 24a, the operation lever 61 is moved via the forward movement of the shift operation cable 25. The operation end 61b side is pushed back forward, and first, the second tension pulley arm 67 is released. Therefore, the pressing force of the second tension roller 48 against the second belt 29 is lost, and power transmission from the second pulley 27 for the flat blade to the pulley 28 for the side blade is cut off. .

Next, when the clutch lever 24 is disengaged from the first-stage locking concave portion 24a and returned forward, the swinging end 61a of the operating lever 61 is connected to the extension portion of the first tension roller arm 62. 65, the first tension roller arm 6 moves in a direction in which the first tension roller 22 separates from the first belt 21.
2 is turned back. As a result, the pressing force of the first tension roller 22 against the first belt 21 is lost, and the transmission of power from the driving pulley 19 to the first pulley for the flat blade is also cut off.

Next, an embodiment of a safety device for a power transmission mechanism according to the present invention will be described with reference to FIGS.

As shown in FIG. 9 and FIG.
3 on the fixed part A side and the tilt housing 41
A lever 70 having a V-shape is provided on the side of the side as a means for detecting the tilt angle of the tilt housing 41. The tilt angle detecting lever 70 detects that the tilt housing 41 has tilted by a predetermined angle (for example, downward α, upward β from the plane cutting position) by more than a predetermined angle, and makes the tilt housing 41 fall below the predetermined tilt angles α, β It acts to detect that there is.

In the illustrated example, the upper swing limit angle β is detected, but if necessary, a similar device may be provided for detecting the lower swing limit angle α.

The tilt angle detection lever 70 has its pivot shaft 71 rotatably supported in the front-rear direction of the body 13. In the illustrated example, the tilt housing 41 is tilted most upward. At this time, the left end (force point side end 70a) is pushed by the connecting rod 37, and the right end (action point side end 70b) swings clockwise in FIG. 9 or FIG. When the tilting housing 41 descends and comes out of the maximum tilting state, it rotates counterclockwise to return to the original state.

As shown in an enlarged view in FIG. 11, a front end 72a of a cable as a safety device operating force transmitting member is provided at the end 70b of the inclination angle detecting lever 70 at the action point side.
Is locked. The operating force transmission cable 72 is initially stretched shortly in the left-right direction of the body 13 and turned to the rear of the body 13 via, for example, a pulley (not shown), and finally shown in FIG. Thus, the rear end portion 72b is extended to the vicinity of the shift lever guide member 24c.

The shift lever guide member 24c is provided with the first stage locking recess 24a and the second stage locking recess 2a.
4b to the moving path of the shift lever 24 (ie,
A lever path opening / closing means 73 for opening and closing a movement path of the shift lever 24 for transmitting the driving force of the engine 1 to the tilting portion B side is provided. The lever path opening / closing means 73 is operatively connected to the inclination angle detection lever 70 by the operating force transmission cable 72, and when the inclination housing 41 reaches a predetermined inclination angle β, the shift lever 24 The movement path is closed, and when the tilt housing 41 deviates from the predetermined inclination angle β, the shift lever 24 operates to open the movement path.

In the illustrated example, the lever path opening / closing means 73 is formed of a metal fan-shaped plate, and the upper surface of the shift lever guide member 24c is centered on the rear end 73a, which is the key portion. To turn left and right along the line. The lever path opening / closing means 73 has a lever path blocking rising piece 73b at a front portion thereof, and has a lever pushing up piece 73c at a side opposed to the second-stage locking concave portion 24b. .

FIG. 13 shows the lever path opening / closing means 73.
The coupling relationship between the shift lever guide member 24c and the operating force transmission cable 72 is shown in an exploded manner.

As shown in FIG. 13, the shift lever guide member 24c has a through-hole 74 for mounting a safety device at a position rearward of the second-stage locking recess 24b.
A cylindrical body 75 for transmitting the operating force of the safety device is inserted into the through hole 74 from below, with a suitable play, so that the cylindrical body 75 can freely rotate. At the upper end of this cylindrical body 75,
The rear end 73a side of the lever path opening / closing means 73 is fixed.

The base end 76a of the cable attachment lever 76 is fitted to the lower part of the cylindrical body 75 from below with an appropriate amount of play so that the cable attachment lever 76 can freely rotate. The rear end portion 72b of the operating force transmission cable 72 is locked to the swing end portion 76b side of the cable attachment lever 76. The cable attachment lever 76 is, for example,
A first tension coil spring 77 (see FIG. 14) for pulling the lever 76 backward of the body 13 and the force-side end 70a of the tilt angle detection lever 70 are turned clockwise as viewed in FIG. 9 or FIG. Due to the balance of the pulling force with the second pulling coil spring 78 urged in the direction, the swinging end portion 76b is normally set so as to face the left-right direction of the machine body 13.

Further, a cylindrical support shaft 79 for rotatably supporting the cylindrical body 75 is inserted from below into the cylindrical body 75, and the cylindrical support shaft 79 is provided with the shift lever guide. It is fixed to a plate-like bracket 80 provided on the member 24c. The bracket 80 also prevents the cable attachment lever 76 from dropping downward.

The cable attachment lever 76 and the cylinder 7
5, a swing end 76 of the cable attachment lever 76
projecting pieces 8 that come into close contact with each other when b swings forward
1, 82 are provided integrally. Further, between the cable attachment lever 76 and the cylinder 75, the cable attachment lever 76 and the cylinder 75 are rotated in opposite directions so that the respective protruding pieces 81 and 82 are always in close contact with each other. A spring body 83 for urging the lever path opening / closing means is interposed. The spring body 83 is in the form of a torsion coil spring, and acts to bias the lever path opening / closing means 73 so as to rotate toward the cable attachment lever 76.

As shown in FIG. 14, in a normal state in which the swinging end portion 76b of the cable attachment lever 76 is oriented in the left-right direction of the body 13, the lever path opening / closing means 73 causes the shift When the movement path of the lever 24 is open, and the swing end portion 76b side of the cable attachment lever 76 is pulled forward by the operating force transmission cable 72, the lever path opening / closing means 73 is opened via the cylinder 75. It turns so as to close the movement path of the shift lever 24.

The lever path opening / closing means 73 operates in a direction in which the shift lever 24 locked in the second-stage locking recess 24b is pushed out of the recess 24b to move the shift lever 24 in the moving path. It is configured to close.

The safety device for a power transmission mechanism according to the present embodiment configured as described above operates as follows.

According to the mowing machine of this embodiment, even if the tilting housing 41 is largely tilted upward, there is no problem in the power transmission system. 41 is the fixed part A
It can be folded and fixed along the side.

However, when the tilt housing 41 is tilted upward to the maximum tilt state, the slope cutting blade 6 accommodated therein is exposed. Under such a condition, the shift lever 24 is erroneously moved to the second stage locking recess 24.
When moved to b, the slope cutting blade 6 starts to rotate unexpectedly, which is very dangerous. Therefore, by preventing the shift lever 24 from moving to the second-stage locking recess 24b due to an operation error or the like, it is possible to prevent the exposed slope cutting blade 6 from unexpectedly starting to rotate. And a safety device according to the present embodiment.

The tilt housing 41 is moved to the maximum tilt state β.
When the connecting lever 37 is tilted upward, the connecting rod 37 that moves upward with this touches the force-side end 70 a of the tilt angle detecting lever 70. As a result, the tilt angle detection lever 70 swings, and the swing end portion 76 b of the cable attachment lever 76 via the operating force transmission cable 72.
Is pulled forward of the body 13. Then, the protruding piece 81 provided on the cable attachment lever 76 presses the protruding piece 82 provided on the cylindrical body 75 to press the cylindrical body 75.
Is rotated in the same direction as the cable attachment lever 76.
When the cylindrical body 75 rotates, the lever path opening / closing means 73 also rotates accordingly, and the lever path blocking rising piece 73b of the lever path opening / closing means 73 is used to lock the shift lever at the second stage. The movement path to the recess 24b is closed. The lever path opening / closing means 73 in this state is shown by a chain line in FIG.

As described above, the shift lever 24
Is prevented from being erroneously moved to the second-stage locking recess 24b.

In the power transmission mechanism according to the present embodiment, the shift lever 24 locked in the second-stage locking recess 24b is pushed out of the recess 24b. The path opening / closing means 73 is operated to close the movement path of the shift lever 24.
For this reason, the shift lever 24 is kept locked in the second-stage locking recess 24b (that is, the side surface cutting blade 6).
When the tilt housing 41 is tilted upward to the maximum tilt state β, the lever path opening / closing means 7 is rotated.
The shift lever 24 is pushed out from the second-stage engaging recess 24b by the lever pushing-up rising piece 73c of No. 3 and the power transmission to the tilting portion B side is automatically cut off.

In some cases, in order to cut the so-called upward slope, it may be desired to rotate the slope cutting blade 6 by tilting the tilting housing 41 upward to the maximum inclined state β. In such a case, the lever path opening / closing means 73 closing the movement path of the shift lever 24 is further rotated with a finger against the urging force of the lever path opening / closing means urging spring 83. Then, the moving route may be temporarily opened. That is, the lever path opening / closing means 73 is manually rotated largely to the state shown by the two-dot chain line in FIG. What is necessary is just to move to the recessed part 24b.

[0086]

According to the first aspect of the present invention, tilting
When the portion has a predetermined inclination angle or more, the
Power is not accidentally transmitted to the tilting part,
Is all.

Further, according to the present invention as set forth in claim 2,
For example, while the power is being transmitted to the tilting portion side, the tilting portion is
When the angle of inclination is set to a predetermined angle, power transmission is automatically shut off.
Is more secure.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a power transmission system of a mower equipped with a power transmission mechanism according to one embodiment of the present invention.

FIG. 2 is a perspective view of a mower equipped with the power transmission system of FIG. 1;

FIG. 3 is a front view of the mower shown in FIG. 2;

FIG. 4 is a perspective view showing how to adjust the tilt angle of the tilting portion and specific means for fixing the tilt angle at a desired angle.

FIG. 5 is a schematic plan view of a main part showing power transmission control means in the power transmission system of FIG. 1;

6 is a perspective view of a main part of FIG. 5, showing a relationship between an operation lever and a first tension roller.

FIG. 7 is a perspective view of a main part of FIG. 5, showing a relationship between an operation lever and a second tension roller.

FIG. 8 is a vertical sectional side view of a main part of FIG. 5, showing a vertical positional relationship among an operation lever, a first tension roller arm, and a second tension roller arm.

FIG. 9 is a schematic view of the mowing machine of FIG. 2 as viewed from the rear, showing a tilting motion state of a tilting portion with respect to a fixed portion.

10 is a schematic view of the mower of FIG. 2 as viewed from the rear,
The maximum tilt state of the tilting portion is shown.

FIG. 11 is a perspective view of the tilt angle detection lever shown in FIGS. 9 and 10;

FIG. 12 is a perspective view showing the vicinity of a shift lever shown in FIG. 2;

13 is an exploded perspective view showing a coupling relationship between the lever path opening / closing means, the shift lever guide member, and the safety device operating force transmission cable shown in FIG.

14 is a plan view of FIG. 12, showing an operating state of the lever path opening / closing means.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 prime mover 24 shift lever 24b lever retaining recess 24c lever guide member 70 inclination angle detecting means 73 lever path opening / closing means A fixed part B tilting part α predetermined inclination angle (downward) β predetermined inclination angle (upward)

Continuation of the front page (56) References JP-U 3-67517 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A01D 34/63-34/90 A01D 69/00-69 / 06 F16H 7/12

Claims (2)

(57) [Claims] And 1. A fixed part (A), and a tilting portion based upon said fixed part (A) (B), wherein the driving force of the prime mover provided in said fixed part (A) side (1) A mechanism for transmitting to the tilting portion (B) side, wherein the tilting portion (B)
Is greater than or equal to a predetermined inclination angle (α, β) and
When the tilt angle falls below a certain tilt angle (α, β), the tilt moves
An inclination angle detecting means (70) that operates according to the operation;
Transmission of driving force from the prime mover (1) to the tilting portion (B)
Lever (24) for controlling the
Open / close the movement path to the driving force transmission shift state of (24)
Lever path opening / closing means (73);
(B) is greater than or equal to the predetermined inclination angle (α, β).
When the lever path opening / closing means (73) is
(24) Closing the movement path and the tilting portion
(B) is equal to or less than the predetermined inclination angle (α, β).
The lever path opening / closing means (73)
(4) The inclination angle detecting means so as to open the movement path.
(70) and the lever path opening / closing means (73)
A power transmission mechanism that is connected . 2. A moving path of the shift lever (24).
While being formed by a lever guide member (24c),
Holding the lever (24) in the driving force transmission shift state
Lever retaining recess (24b) to move the lever guide member
(24c), and the lever (24) is connected to the lever
The lever path extends in a direction of pushing out from the retaining recess (24b).
When the opening / closing means (73) operates, the lever
The moving route of (24) is closed.
The power transmission mechanism according to any one of the above.