JP2574938Y2 - Work vehicle safety devices - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a working vehicle provided with a working device, and more particularly, to a working vehicle which does not operate the working device when a brake is not operated. Related to safety devices.

[0002]

2. Description of the Related Art In a work vehicle equipped with a work device such as a boom that can freely move up and down on a body of a vehicle that can travel freely, such as an aerial work vehicle or a crane vehicle, the operation of the work device is controlled by hydraulic pressure. There is something that is used to do it. Here, the hydraulic oil for operating the working device is supplied by driving a hydraulic pump provided on the vehicle body. The driving of the hydraulic pump uses an output of a traveling engine of the vehicle as a power take-off mechanism (PTO). ). Only when the working device is activated, the PT
Activate O to drive the hydraulic pump.

[0003]

In such a working vehicle, it is preferable to keep the vehicle from running while the working device is operating in order to ensure the safety of the work. The hydraulic pump has an engine speed of about 1500 rpm.
In this case, the speed is reduced to about 1000 rpm by the PTO to perform an appropriate operation. Therefore, if the vehicle is driven with the PTO activated, the engine may rotate at a high speed, which may adversely affect the PTO reduction gear body.

[0004] The present invention has been made in view of such circumstances, and when the power take-off mechanism is operating, the vehicle cannot travel and the vehicle cannot travel. It is an object of the present invention to provide a safety device for a work vehicle having a configuration in which a power take-off mechanism cannot be operated.

[0005]

In order to achieve the above object, the safety device of the present invention is used for driving a hydraulic pump which is a drive source of a working device disposed on a movable vehicle body. And an engine serving as a drive source for running the vehicle. In addition, a power take-off mechanism capable of transmitting the driving force of the engine to the hydraulic pump is provided, a power take-off operation detector for detecting that the power take-off mechanism is operated, and a side brake provided on the vehicle body is in a braking state. And a braking state detector for detecting And an engine stop means for stopping the operation of the engine when the braking state detector detects that the side brake is released and the power take-off operation detector detects that the power take-off mechanism has been activated. It has.

[0006]

With such a safety device, the power take-off mechanism can be operated only when the side brake is in a braking state, that is, only when the vehicle is stopped, and the power take-off mechanism is operating. Sometimes the engine stops if the handbrake is released.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First, an aerial work vehicle equipped with the safety device according to the present invention will be described with reference to FIG.
The aerial work vehicle 1 is provided with a swivelable swivel 3 at the rear of a vehicle body 2 of a free-running truck (vehicle) T;
A work device for a high place, comprising a boom 4 pivotally attached to the upper part of the boom so as to be able to move up and down and freely expandable and contractable, and a work table 5 attached to a tip end of the boom 4 is mounted.

The operator can move to an arbitrary height and work by operating the turntable 3 and the boom 4 while riding on the worktable 5. The operations of the swivel base 3 and the boom 4 are performed by the operation of hydraulic actuators (a swivel motor 7, an up-and-down cylinder 8, and a telescopic cylinder 9). The attached hydraulic pump P. Here, the hydraulic pump P uses a power take-off mechanism (PT) to output the output of the traveling engine E that drives the rear wheels via the transmission TM during traveling of the truck T.
O). The battery B mounted on the lower part of the vehicle body 2 supplies electric power for controlling a safety device and operating the engine E, which will be described in detail later.

The PTO includes a transmission T for running the vehicle.
A clutch (not shown) for a hydraulic pump having a configuration different from the clutch provided in M is provided. The clutch for the hydraulic pump is connected when a PTO operation switch 10a attached to an operation device 10 provided in the vehicle body 2 is turned on, and the clutch is connected. Activates the PTO.
The operating device 10 is also provided with a PTO detection switch (power take-off operation detector) 11 for detecting that the PTO has been activated by turning on the PTO operation switch 10a. In the driving cabin C, there is provided a side brake lever SB for performing a braking operation of a side brake, and a side brake detection switch (braking state detector) 21 for detecting that the side brake is in a braking state. ing.

In the aerial work vehicle having such a configuration, when the boom 4 is extended and the worker is working at an aerial position, the aerial work vehicle 1 travels to ensure work safety. Not preferred above. Further, since the appropriate rotation speed of the hydraulic pump P is about 1000 rpm, the hydraulic pump P is driven by decelerating the rotation of the engine E in the PTO. In this case, the rotation speed of the engine E is about 1500 rpm, and if the rotation speed of the engine E is further increased, the speed reduction device body of the PTO may be adversely affected. Therefore, for example, when the vehicle is driven without stopping the PTO after the work is completed, the
When the rotation speed exceeds rpm, the rotation speed of PTO becomes 1000r
pm, which may adversely affect the PTO reduction gear body. Therefore, the aerial work vehicle according to the present invention is provided with a safety device to correct such a problem.

As shown in FIG. 1, this safety device has a PTO
P that is activated by turning on and off the detection switch 11
A TO relay CR1 and a side brake relay CR2 that is operated by turning on and off the side brake detection switch 21 are provided. These relays C
R1 and CR2 have contacts C1 and C2. The contact C1 has a normally open contact configuration, and the contact C2 has a normally closed contact configuration. Also provided is an engine stop relay CR3 that is activated by turning on and off the contacts C1 and C2 of these relays CR1 and CR2. When the engine stop relay CR3 is activated, the normally closed contact C3 is turned off. , The supply of power from the battery B to the engine E is cut off, and the engine E stops.

A description will be given of a case in which the running of the vehicle and the operation of the PTO are performed in the aerial work vehicle equipped with the safety device configured as described above. First, when the vehicle is driven to move the aerial work vehicle 1 to the work site, the PTO
Need not be operated, the PTO detection switch 11 is off. Therefore, not only when the side brake is in the braking state, but also when the side brake is released, the engine stop relay CR3 does not operate.
The operation of the engine E is possible, and the aerial work vehicle 1 can travel freely.

Next, the aerial work vehicle 1 moved to the work site
When working with high altitude work equipment, the PTO
When the PTO operation switch 10a is turned on to operate the switch, the PTO detection switch 11 is also turned on, the relay CR1 is operated, and the contact C1 is turned on. At this time, if the side brake is not in the braking state, the side brake detection switch 21 is in the off state.
Reference numeral 2 keeps the ON state, and when the engine stop relay CR3 is operated, the contact C is turned off and the engine E is stopped.

When the side brake detection switch 21 is on when the PTO operation switch 10a is turned on, the PTO is activated. However, when the side brake is released, the side brake detection switch 21 is turned off. Even during the operation of the PTO, the engine E is stopped by operating the engine stop relay CR3. For this reason, it is possible to prevent an unexpected accident that occurs when the vehicle runs when the worker is working at a high place. PTO operation switch 1
When the vehicle runs while forgetting to turn off the motor 0a, it is possible to prevent the engine E from rotating at a high speed, and prevent the PTO from rotating more than a predetermined number of revolutions and adversely affecting the PTO reduction gear body.

Therefore, the operation of the PTO must be stopped in order to run the high-altitude work vehicle 1, so that it is possible to prevent the PTO from being adversely affected by the high rotation of the engine E. In addition, PTO
If the engine E is stopped due to the release of the side brake during the operation of, the brake operation of the side brake lever SB is performed again to start the engine E.

In the above embodiment, the safety device circuit is controlled by relay control. However, the present invention is not limited to this. The controller 30 for controlling the engine as shown in FIG. May be used. The controller 30 includes a PTO detection switch 31 and a side brake detection switch 31.
Is controlled based on the detection signal from the battery B to the engine E, and control is performed such that the PTO operates only when the side brake is braked.

[0017]

As described above, the work vehicle safety device according to the present invention has a power take-off mechanism capable of transmitting the driving force of the engine for driving the hydraulic pump and for driving the vehicle body to the hydraulic pump. Have. The vehicle also includes a power take-off operation detector that detects that the power take-off mechanism has been activated, and a braking state detector that detects that the side brake provided on the vehicle body is in a braking state.
Then, when the braking state detector detects that the side brake is released and the power take-off operation detector detects the operation of the power take-off mechanism, the operation of the engine is stopped by the engine stop means. As a result, the power take-off mechanism does not operate when the side brake is not braked, and the power take-off mechanism must be stopped when the vehicle is driven. In addition, the engine does not rotate at a high speed and does not adversely affect the speed reducer body of the power take-off mechanism.

[Brief description of the drawings]

FIG. 1 is a block diagram of a safety device for a work vehicle according to the present invention.

FIG. 2 is a side view of an aerial work vehicle provided with the safety device.

FIG. 3 is a block diagram of a safety device according to another embodiment of the present invention.

[Explanation of symbols]

4 Boom 5 Work table 11 PTO detection switch (power take-off operation detector) 21 Side brake detection switch (braking state detector) CR3 Engine stop relay (engine stop means) B Battery E Engine P Hydraulic pump PTO Power take-off mechanism SB side Brake lever

Claims (1)

(57) [Scope of request for utility model registration] 1. A movable vehicle body, a working device disposed on the vehicle body, a hydraulic pump that is a drive source of the working device, and used for running the vehicle body and for driving the hydraulic pump. An engine provided on the vehicle body, a power take-off mechanism capable of transmitting a driving force of the engine to the hydraulic pump, a power take-off operation detector for detecting that the power take-off mechanism has been operated, and the vehicle body A brake provided on the vehicle; a braking state detector for detecting a braking state of the side brake; a braking state detector for detecting that the side brake is released, and a power take-off mechanism being turned on. Engine stop means for stopping the operation of the engine when the power take-off operation detector detects that Safety device for a work vehicle according to claim.