JPH0448132B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a loader, which is an industrial vehicle having a cargo handling device such as a bucket, a shovel, or a fork.
The present invention relates to a safety device that locks a control device such as a foot pedal to a neutral position (a position where power supply to a cargo handling device is stopped) when a driver's departure from the coordinate system is detected.

[Prior Art] For loaders, for example, skid steer loaders are provided which have a structure in which it is impossible to get on and off from the seat because the side of the seat is covered by a drive arm, so the user has no choice but to climb over a cargo handling device to get on and off the seat. has been done. In this skid steer loader, there is a demand for the development of a safety device that prevents the cargo handling device from malfunctioning when getting on and off the vehicle.

For this reason, conventionally, a control device that controls cargo handling equipment such as a bucket or shovel is connected to a seatbelt using a wire, and when the driver takes off the seatbelt to get out of the vehicle, the wire is pulled. A safety device has been developed in which the control device is automatically locked in the neutral position, thereby stopping the supply of power to the cargo handling equipment (Japanese Patent Application Laid-Open No. 1983-1999).
147940).

The applicant has recently developed a safety device that is a further development of the above-mentioned safety device. This safety device is
It is related to Publication No. 59-182983 (unknown at the time of filing of this application), and includes a locking device that locks a control device such as a foot pedal in a neutral position, and a locking device that detects when a driver takes a seat and leaves the seat. It has a sensor and an actuating device that operates the lock device in response to the sensor's leave signal and unlocks the lock device in response to the sensor's seat signal.

The safety device disclosed in Japanese Utility Model Application No. 59-182983 described above has the advantage that the sensor can quickly detect when the driver leaves the loader from the seat.

However, if the driver bounces significantly on the seat when the loader travels on a rough road with large irregularities, the driver and the seat will be displaced relative to each other. For example, a driver sitting in a seat may have his or her hips separated from the seat by several centimeters. If the band causes a relative displacement between the driver and the seat, the sensor may issue a signal to leave the seat even though the driver is working on the seat, and the locking device may be erroneously activated. Therefore, even though there is no need to lock the foot pedal control device in the neutral position, there is a risk that it will be locked in the neutral position by mistake.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and its purpose is to solve the problem even when the loader travels on a rough road with large bumps and the driver bounces on the seat. An object of the present invention is to provide a loader safety device that is free from the risk of locking a control device due to malfunction.

[Means for Solving the Problems] A loader safety device according to the present invention includes a cargo handling device driven by power, a drive position for supplying power to the cargo handling device, and a drive position for supplying power to the cargo handling device. a control device that has a neutral position for stopping the vehicle and can be operated to any drive position or neutral position; a locking device that locks the control device in the neutral position when activated, comprising a seat on which a driver sits; a sensor that detects when a person takes a seat or leaves the seat and issues a seat signal and a seat leave signal; and a sensor that operates the lock device based on the seat leave signal from the sensor and locks the lock device based on the seat signal from the sensor. This device is characterized by comprising an actuating device that releases the signal, and a delay device that delays the leave signal from the sensor by a predetermined time and transmits the signal to the actuating device.

A cargo handling device is a device that performs cargo handling work. A typical cargo handling device is a bucket that scoops up dirt and sand. The cargo handling device is driven by a power source built into the loader body. The power source is typically a fluid pressure source such as a hydraulic pump, or a power source such as a battery.

The control device is a device that supplies power to the cargo handling device or stops supplying power to the cargo handling device. Therefore, the control device has a drive position where power is supplied to the cargo handling device, and a neutral position where power supply is stopped. The driving position and the neutral position may be one or more. Typical control devices include a foot pedal and a manually operated lever. If the control device is a foot pedal, a lock portion can be formed at one end of the foot pedal.

The seat is for the driver to sit on, and can be the same as the conventional one. Preferably, the seat has a hollow part for incorporating the sensor.

A locking device is a device that, when actuated, locks the control device in a neutral position. The lock device includes a rotatably supported lock bar and a spring that biases the lock bar.The biasing force of the spring causes the lock bar to rotate and the end of the lock bar to be attached to the control device. The control device can be locked in a neutral position by being locked with the lock portion of the control device.

The sensor detects when the driver takes and leaves the seat. Sensors are generally built into the seat. Examples of the sensor include a pressure sensor installed on the seat to detect pressure caused by sitting;
Alternatively, various sensors can be selected, such as a pressure switch such as a limit switch that connects an electric circuit when pressed, an optical sensor that detects the shielding of light due to the driver's seat, or a photoelectric switch that disconnects the electric circuit due to the shielding.

The actuating device receives a seat-leaving signal from the sensor and operates a locking device using the seat-leaving signal to lock the control device at a neutral position, and also receives a seat-taking signal from the sensor and locks the locking device using the seat-taking signal. This is a device to release the device. As components of the actuating device, for example, electromagnetic actuators, electromagnetic clutches, electromagnetic valves, drive motors, etc. can be used. Further, a link mechanism may be added in addition to the electromagnetic actuator, electromagnetic clutch, etc.

The delay device is a device that delays the sensor's leave signal and transmits it to the actuating device. The delay device can be an electric circuit that includes a capacitor or a switching transistor capacitor and utilizes charging and discharging of the capacitor, as shown in the embodiments described later. In some cases, a timer may be used, and when the timer receives the leave signal from the sensor, the signal may be delayed by the time set in the timer and transmitted to the actuator.

[Operation] When the driver leaves the loader seat, the sensor detects this. Then, the leave signal is transmitted to the actuating device after a predetermined time via the delay device, and the actuating device is actuated. As a result, the control device is locked in a neutral position, ie a position where the power supply to the cargo handling equipment is stopped. In the locked state, even if the driver steps over the cargo handling device and exits the loader vehicle, the cargo handling device will not malfunction, so it is safe.

Meanwhile, when the driver takes a seat in the loader, a sensor detects this. Then, the lock device is unlocked by the seating signal from the sensor. The unlocked control device can be operated to a drive position, that is, a position for supplying power to the cargo handling device. Therefore, the driver can drive the cargo handling device of the loader using the control device, and can perform cargo handling operations using the cargo handling device.

By the way, when the loader travels on a rough road with large bumps, the driver may bounce off the seat. When the vehicle bounces, the driver is displaced from the normal position and the driver and the seat are displaced relative to each other. for example,
A gap of several centimeters is created between the driver's lower back and the seat. Then, the sensor detects the above displacement and issues a leave signal. This leave signal is transmitted to the delay device, which delays the signal by a predetermined period of time, and transmits it to the actuating device. The actuating device is therefore actuated and the locking device attempts to lock the control device in the neutral position. However, when the seat bounces, the displacement between the seat and the driver is small, for example, only a few centimeters at most, and the bounced driver returns to the original position in the seat. Therefore, the sensor again detects the seating signal and the actuator attempts to unlock the locking device. As a result, the actuation of the actuating device which attempts to lock the control device in the neutral position is aborted. Therefore, it is possible to prevent the lock device from malfunctioning due to bouncing.

[Effects of the Invention] The loader safety device according to the present invention prevents the lock device from malfunctioning even when the loader is traveling on a rough road with large bumps and the driver bounces significantly on the seat. I can do it.

[Example] Hereinafter, an example of the present invention will be described based on the accompanying drawings.

(Structure) FIG. 1 is a side view of essential parts showing one embodiment of the present invention, and FIG. 2 is an overall perspective view of a skid steer loader according to this embodiment.

As shown in FIG. 2, the skid steer loader according to this embodiment includes a vehicle body 10 having an engine housed therein, a plurality of wheels 12 on both side surfaces, and a cab 13 above. A bucket 1 serving as a cargo handling device is disposed at the front via an arm 16 and a hydraulic cylinder 17, and a driver's seat 3 is provided on the upper surface of the vehicle body 10.
A foot pedal 2 is provided as a control device on the upper surface of the vehicle body 10 in front of the seat 3, and a safety device A (described in detail later) whose main part is shown in FIG. 1 is provided.

As shown in FIG. 1, the safety device A includes a lock device 4 provided on the floor surface 10a of the vehicle body 10 and a limit switch 5 as a sensor built into the seat 3.
, a plunger type solenoid 6 as an actuating device installed on the floor surface 10a, and a delay device 7 provided on the vehicle body 10.

The locking device 4 includes a bearing member 40 fixed to the floor surface 10a, a link rod 41 whose both ends are held by the bearing member 40, a lock bar 42 fixed to the link rod 41 and having a lock portion 42a at the tip, and a link rod. 41, and a coil-shaped spring 44 whose one end is attached to the vehicle body front plate 10b and whose other end is locked to the lever 43.

A frame 50, a spring 51 provided within the frame 50, and an operation plate 52 biased upward by the spring 51 are provided around the limit switch 5 as a sensor. When the driver takes a seat in the seat 3, the switch portion 5a of the limit switch 5 is pressed by the operation panel 52.
When the limit switch 5 is turned on and the driver leaves the seat, the spring 51 causes the operation panel 5 to
2 moves up, and limit switch 5 turns OFF.
state.

The foot pedal 2 as a control device has a convex portion 20
has. The foot pedal 2 is attached to the vehicle body 10 by rotatably supporting the convex portion 20 via a pin 20a to a block 21 fixed to the floor surface 10a. A hook-shaped lock portion 22 is provided at one end of the foot pedal 2. The foot pedal 2 has a driving position for driving the bucket belt 1 and a neutral position for stopping driving the bucket belt 1, and can be rotated around a pin 20a by stepping on the foot and operated to each position. When the foot pedal 2 is operated to each position by stepping in this way, the control valve 25 is actuated via the rod 25a which is pivotally supported on the block 21 by the pin 25b, thereby controlling the drive of the bucket belt 1. .

Plunger type solenoid 6 as actuating device
is fixed to the floor surface 10a. The solenoid 6 has a rod 60 pivoted by a pin 60a. The other end of the rod 60 is pivotally supported on the lever 43 by a pin 60b. Solenoid 6 is
It is connected to the delay device 7 via a lead wire 91, and receives a leave signal and a seat seat signal via the lead wire 91.

The delay device 7 is connected to the limit switch 5 via a lead wire 90 and to an on-vehicle battery 93 via a lead wire 92. This delay device 7 delays the leave signal from the limit switch 5 by a predetermined period of time and transmits the signal to the solenoid 6 via a lead wire 91. Specifically, the delay device 7 has a configuration shown in FIG. That is,
As shown in FIG. 3, the delay device 7 includes a first resistor 70, a second resistor 71, a third resistor 72,
A fourth resistor 73, a diode 74, an electrolytic capacitor 75, and a protective Zener diode 76
and a transistor 77. Note that the third resistor 72 is connected to the lead wire 90.
It is connected to the limit switch 5 via.
The transistor 77 is a PNP type transistor,
The collector of the transistor 7 is connected to the solenoid 6 via the lead wire 91.

(Function) Now, in FIG. 1, when the driver sits on the seat 3, the limit switch 5 is turned on. Then, as is clear from FIG. 3, the electrolytic capacitor 75 and diode 7 are
4. Current flows through the third resistor 72. When the electrolytic capacitor 75 is charged, no current flows through the electrolytic capacitor 75, and the voltage of the electrolytic capacitor 75 becomes equal to the voltage of the vehicle battery 93. At the same time, the first resistor 70 and the second resistor 7
1. Current flows through the third resistor 72. Therefore, a base current flows through the transistor 77, turning on the transistor 77, and a current is transmitted from the vehicle battery 93 to the solenoid 6 via the lead wire 92. That is, a seating signal flows to the solenoid 6. As a result, the solenoid 6 is actuated to pull the rod 60 shown in FIG.
3. Move the lock bar 42 in the direction of the arrow 45 with the link rod 4.
1, thereby disengaging the lock portion 42a of the lock bar 42 from the lock portion 22 of the foot pedal 2, thereby unlocking the lock device. In this unlocked state, the driver can operate the foot pedal 2 to drive the bucket 1 via the control valve 25 and perform cargo handling work.

On the other hand, when the driver leaves the seat 3 after completing cargo handling work, the spring 51 shown in FIG. 1 expands, so the limit switch 5 is turned off.
Then, as is clear from FIG. 3, the current flowing from the vehicle battery 93 to the limit switch 5 is:
It is shielded, and the base current of transistor 77 no longer flows. Therefore, normally, the transistor 77 would be turned off at the same time as the driver leaves the seat. However, in this embodiment, the electrolytic capacitor 75 is charged as described above, and since the charged electrolytic capacitor 75 is discharged, conduction occurs between the emitter E and the base B of the transistor 77, and a base current flows to the transistor 77. In addition, the first
The resistor 70 acts to prevent excessive current from flowing through the transistor 77, thereby allowing an appropriate base current to flow through the transistor 77. As a result, the transistor 77 is not turned off and continues to be turned off for a predetermined period of time. After a predetermined period of time, the transistor 77 is turned off, thereby cutting off the current to the solenoid 6. That is, in this embodiment, the solenoid 6 is kept energized for a predetermined period of time determined by the discharge of the electrolytic capacitor 75.

As described above, when the limit switch 5 is turned off and the energization to the solenoid 6 is cut off after a predetermined period of time, the force by which the solenoid 6 pulls the rod 60 in the direction of the arrow 61 shown in FIG. 1 disappears. Therefore, the lever 43 and the rod bar 42 are rotated about the link rod 41 in the direction opposite to the arrow 45 by the biasing force of the spring 44, and the lock portion 4 of the lock bar 42 is rotated.
2a is fitted into the lock portion 22 of the foot pedal 2, as shown by the dashed line in FIG. 1, thereby locking the foot pedal 2 in the neutral position. With the foot pedal 2 locked in the neutral position in this way, even if the driver accidentally depresses the foot pedal 2, the
The foot pedal 2 is not operated, thereby preventing the bucket 1 from malfunctioning, and it is safe to step outside the vehicle beyond the bucket 1.

By the way, when the skid steer loader according to this embodiment travels on a rough road with large irregularities, the driver may bounce from the seat 3 in the vertical direction. In this case, when the limit switch 5 detects that the driver leaves the seat due to bouncing, the limit switch 5 immediately turns off. Then, as described above, if the electrolytic capacitor 75 were not present, the transistor 77 would immediately turn off. However, in this embodiment, at the same time that the limit switch 5 is turned off, the electrolytic capacitor 75 is discharged, so that the emitter E and the base B of the transistor 77 are rendered conductive, and the transistor 77 is not turned off for a predetermined period of time. When the driver bounces, the distance between the driver's waist and seat 3 is only a few centimeters at most, and the driver only leaves the seat momentarily, so the driver's waist is once again seated on seat 3. do. That is, the limit switch 5 is turned on before the electrolytic capacitor 75 finishes discharging. Therefore, the first resistor 70 and the second resistor are connected again from the on-vehicle battery 93.
Current flows through the resistor 71 and the third resistor 72, and
A base current flows through transistor 77. Therefore, despite the bounce, the transistor 77 continues to be turned on, and the current continues to flow to the solenoid 6.

Therefore, in the present embodiment, even if the driver's hips accidentally leave the seat 3 due to bounce, the energization to the solenoid 6 is not cut off, unlike in the conventional case, and the driver's legs may be accidentally removed. There is no risk of locking the foot pedal 2.

Note that the Zener diode 76 functions to prevent the transistor 77 from being damaged.

(Other Embodiments) Another embodiment of the delay device according to the present invention is shown in FIG. The delay device 8 according to this embodiment delays the leave signal from the limit switch 5 and transmits it to the solenoid 6 similarly to the delay device 7 according to the above-described embodiment, and as shown in FIG. 1 resistor 81, a second resistor 82 for supplying an appropriate base current, and a third resistor 83 for stabilization.
, a voltage capacitor 84 , an NPN type switching transistor 85 , a relay 89 having a relay coil 86 and a relay contact 87 , and a diode 88 .

Now, when the driver takes a seat in seat 3, limit switch 5 is turned on. Then, current flows from the vehicle battery 93 to the electrolytic capacitor 84 via the first resistor 81, and the electrolytic capacitor 84 is filled. Furthermore, a base current flows to the switching transistor 85 via the second resistor 82. As a result, conduction occurs between the collector and emitter of switching transistor 85, transistor 85 is turned on, and current flows from vehicle battery 93 to relay coil 86. Then relay contact 87
is activated and turns ON, and current flows through solenoid 6. As a result, the lever 43 and the lock bar 42 are rotated in the direction of the arrow 45, as in the embodiment shown in FIG. 1, and the foot pedal 2 is thereby unlocked.

On the other hand, when the driver leaves the seat 3, the limit switch 5 is immediately turned off. In this case, if the electrolytic capacitor 84 is not present, the current flowing through the first resistor 81 and the second resistor 82 is cut off, so that the switching transistor 85 is immediately turned off at the same time as the limit switch 5 is turned off. However, in the embodiment shown in FIG. 4, the electrolytic capacitor 84 is discharged at the same time that the limit switch 5 is turned off, so that the base current continues to flow into the switching transistor 85 via the second resistor 82. Therefore, during the discharge time, the base current continues to flow through the switching transistor 85, and the switching transistor 85 continues to be turned on. After a predetermined period of time has elapsed, the base current stops flowing, so the switching transistor 85
is turned off, no current flows through the relay coil 86, the relay contact 87 becomes OFF, and therefore no current flows to the solenoid 6. That is, in the embodiment shown in FIG.
After being turned off, the delay device 8 delays the supply of electricity to the solenoid 6 for a predetermined period of time.

By the way, when the car bounces, the distance between the driver's waist and the seat is only a few centimeters at most.
The driver only leaves his/her seat momentarily. That is, while the electrolytic capacitor 84 is discharging, the driver takes the seat 3 again and the limit switch 5 is turned on.
state. Therefore, by the time the electrolytic capacitor 84 finishes discharging, the first
A current flows through the resistor 81. Therefore, regardless of the bound, the switching transistor 85
continues to turn on, and current continues to flow to solenoid 6.

Also in the embodiment shown in FIG. 4, if the driver remains seated until the electrolytic capacitor 84 finishes discharging, it is possible to prevent the solenoid 6 from being de-energized when driving on a rough road. In addition, the diode 88
protects the switching transistor 85 from the surge voltage of the relay coil 86.

[Brief explanation of the drawing]

Figures 1 to 3 show one embodiment of the present invention, Figure 1 is a side view of the main parts of the safety device, Figure 2 is a perspective view of the entire skid steer loader, and Figure 3 is a delay FIG. 3 is an electrical circuit diagram of the device. FIG. 4 shows another embodiment of the present invention, and is an electrolytic circuit diagram of a delay device. In the figure, 1 is a bucket (cargo handling equipment), 2 is a foot pedal (control device), 3 is a seat, 4 is a lock device,
5 is a limit switch (sensor), 6 is an actuating device, and 7 and 8 are delay devices.

Claims (1)

[Scope of Claims] 1 A cargo handling device driven by power, a drive position for supplying power to the cargo handling device, and a neutral position for stopping the supply of power; The vehicle is equipped with a control device that can be operated in a neutral position, a seat on which a driver sits, a lock device that locks the control device in a neutral position when activated, and a seat signal that detects when the driver takes or leaves the seat. and a sensor that issues a leave signal; an actuator that activates the lock device in response to the leave signal from the sensor and unlocks the lock device in response to the seating signal from the sensor; A safety device for a loader comprising a delay device for delaying and transmitting a signal to an actuating device. 2. The control device is a foot pedal and has a lock portion at one end, and the lock device includes a rotatably supported lock bar and a spring that biases the lock bar. 2. A safety device for a loader according to claim 1, wherein said foot pedal is locked in a neutral position by rotating said lock bar by a force and locking an end of said lock bar in said lock portion. 3. The loader safety device according to claim 1, wherein the actuating device includes an electromagnetic actuator or a drive motor. 4. The loader safety device according to claim 1, wherein the sensor is a pressure switch such as a limit switch built into the seat portion of the seat.