JP2996762B2 - Work machine interference prevention circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates, in digging loading vehicle such as a power shovel, to the working machine interference preventing circuit for preventing interference with the cab of the work machine when working.

[0002]

2. Description of the Related Art In a vehicle for excavation loading such as a power shovel, a work machine including a boom, an arm, a bucket, and the like is generally provided on an upper revolving structure. The arm provided at the tip of the boom and the bucket at the tip of the boom rotate forward and backward, and interfere with the driver's cab provided at the top of the upper revolving unit. There is no.
However, when digging to the side of the vehicle, the above-mentioned working machine cannot dig, so the conventional boom is divided up and down, and the upper boom is pin-coupled so that it can rotate to the left and right with respect to the lower boom. There is one that can be used to make a trench. In a vehicle for excavation loading having such a mechanism,
When the upper boom is offset to the cab side, the working range of the arm or bucket includes a danger zone that interferes with the cab.

[0003]

As a countermeasure in such a case, when a work machine enters into an area that interferes with the cab,
There is a means to sound the buzzer, but in this case, it is necessary to stop the operation of the work machine in response to the buzzer, and in the case of automatic stop, there is a pilot hydraulic pump that supplies discharge oil to the pilot pressure control valve to be operated , The two-position switching lock valve provided in the middle of the circuit is switched to the direction in which the drain is drained, and automatically stopped suddenly from a certain work machine speed. Therefore, a sudden shock is applied to the vehicle body to automatically stop the vehicle, which causes a load spill or the like. Also, the automatic stop position varies due to the difference in speed. In order to release the lock valve, an automatic lock button is provided and released by mechanically pressing the button.

In view of the above, the present invention takes into consideration the speed of a work machine when a bucket enters a predetermined range, instead of suddenly stopping automatically when entering a danger area. It is an object of the present invention to provide a work implement interference prevention circuit capable of reducing a shock by changing a speed reduction rate to solve the drawbacks of the prior art.

[0005]

According to the present invention , as a means for solving the above-mentioned problems of the prior art, a work machine mounted on a vehicle body is bent toward a cab after being offset toward a front side of a cab. In a vehicle for excavation loading that is operated by a pilot pressure control valve so that it can move, signals from each potentiometer that detects the boom angle, arm angle, and offset angle of the work machine are input, and the work machine interferes
Judge that you have entered the danger area, and
Equipped with a controller that calculates the degree signal .
Lock that changes the speed reduction rate of the work machine by these output signals
The valve is connected to the pilot hydraulic pump and the oil
With pilot pressure control valve operated by supply
Is provided on the circuit between, characterized in that a proportional electromagnetic relief valve Ru changing the set pressure by the output signal of the controller to the circuit.

[0006]

According to the above construction, the speed of the working machine is controlled so as to gradually decrease by changing the set pressure reaching the pilot pressure control valve with the electromagnetic proportional relief valve.

[0007]

DETAILED DESCRIPTION FIG. 1 is an illustration of an example of a working machine interference preventing circuit engaged Wa Ru in the present invention, FIG. 2 is an explanatory view of a side face of the excavation loading a vehicle to which the present invention is applied, FIG. 3 is present BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the plane of the vehicle for excavation loading to which this invention is applied.

[0008] the vehicle body 1 to which the present invention is applied, FIG. 2
And as shown in FIG. 3, the undercarriage 18 is provided,
An upper swing body 19 is provided on the lower running body 18 so as to be freely swingable. The upper revolving structure 19 is provided with the following components constituting the working machine 2. That is, the upper revolving superstructure
A base end of a first boom 20 is mounted on 19, and the first boom 20 can be raised and lowered by a boom cylinder 21. The second boom 22 can be offset in the left-right direction by an offset cylinder 23 at the tip of the first boom 20, and the third boom 24 is attached to the tip of the second boom 22. An arm 25 is rotatable vertically by an arm cylinder 26 at the tip of the third boom 24, and the bucket 27 is loaded and dumped by a bucket cylinder 28 provided on the arm 25. A boom potentiometer 8 as a sensor for detecting a boom angle α for detecting the position of the first boom 20 is mounted on the base side surface of the first boom 20, and the position of the arm 25 is set on the third boom 24. An arm potentiometer 9 as a sensor for detecting an arm angle β to be detected is mounted, and an offset potentiometer as a sensor for detecting an offset angle γ for detecting an offset amount of the second boom 22 is provided at an offset link portion. 10 is mounted. In the figure, 3 is the upper revolving superstructure 1
9 is a driver's seat.

FIG. 1 shows a main part of the present invention. Two positions are provided in a circuit 6 between a pilot hydraulic pump 5 and a pilot pressure control valve 4 which is operated by supplying oil discharged from the hydraulic pump 5. A switching lock valve 7 is provided, and this valve 7 is connected to signals 11, 9 from potentiometers 8, 9, 10.
In those connected to the output signal 1 5 of the controller 14 to 12 and 13 to receive and to calculate the proportional electromagnetic relief valve 17 provided in the circuit 6 of the pilot hydraulic pump 5, the output signal 16 of the electromagnetic proportional relief valve 17 controller 14
Is used to change the set pressure. In the figure, 29 is a tank.

Next, the operation will be described. When each operation lever (not shown) of the pilot pressure control valve 4 is operated, each part of the work machine 2 is operated, and the boom cylinder 21, the arm cylinder 26, and the offset cylinder 23 are extended and retracted, whereby the first boom 20, the arm 25, and the second 2
The boom 22 operates. The position of the first boom 20 is detected by the boom potentiometer 8 when the first boom 20 rotates. The position of the arm 25 is detected by the arm potentiometer 9 when the arm 25 rotates. Similarly, the offset amount of the second boom 22 is detected by the offset potentiometer 10 when the second boom 22 rotates. Signals 11, 1 detected by the potentiometers 8, 9, 10
2 and 13 are input to the controller 14. The controller 14 determines whether or not the bucket 27 has entered the danger area based on the determined relationship between these three signals, and if so, differentiates the boom angle α and arm angle β signals from the potentiometers to determine the speed. The output signal 1 is reduced by changing the speed reduction rate according to the speed of the work machine as a signal.
5 is sent to the lock valve 7, and the lock valve 7 uses the pilot oil control valve to discharge oil from the pilot hydraulic pump 5.
It operates to cut off the supply to the 4, but the circuit pressure of the pilot pressure control valve 4 is controlled by the pressure so set pressure of the electromagnetic relief valve 17 is varied by the output signal 16 from the controller 14 to the front Since the work implement speed is also decreasing, the shutoff operation of the lock valve 7 is performed gently, and the shock generated by the switching is reduced.

[0011]

According to the present invention , as described above, the pilot pressure control valve is provided so that the working machine mounted on the vehicle body can be bent toward the cab after being offset toward the front of the cab. Excavation loading vehicle operated by
, Input signals from the potentiometers for detecting the boom angle, arm angle and offset angle of the working machine, determine that the working machine has entered the danger area,
A controller that calculates the speed signal according to the machine speed is provided.
The speed of the work machine is reduced by the output signal from the controller.
The lock valve that changes the bottom rate is
Pilot pressure operated by supply of discharge oil from hydraulic pressure
It is provided on the circuit between the control valve, because providing the electromagnetic proportional relief valve Ru changing the set pressure by the output signal of the controller to the times <br/> path rapidly upon entering the working range of the bucket has been determined It is possible to gradually stop the work speed immediately before the automatic stop, and therefore, it is possible to significantly reduce the shock generated as compared with the conventional case where the automatic stop is suddenly performed automatically.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of a work machine interference prevention circuit according to the present invention.

FIG. 2 is an explanatory side view of a vehicle for excavation loading to which the present invention is applied.

FIG. 3 is an explanatory plan view of a vehicle for excavation loading to which the present invention is applied.

[Explanation of symbols]

1: vehicle body, 2: work machine, 3: cab, 4: pilot pressure control valve, 5: pilot hydraulic pump, 6:
Circuit, 7: lock valve, 8 to 10 : potentiometer, 1
1 to 13 : signal, 14: controller, 15 , 16: output signal, 17: solenoid proportional valve, α: boom angle, β: arm angle, γ: offset angle.

Claims (1)

(57) [Claims] An excavation loading vehicle in which a working machine mounted on a vehicle body is offset by a forward side of a cab and operated by a pilot pressure control valve so as to bend toward a cab. Input the signal from each potentiometer that detects the boom angle, arm angle, and offset angle of the work equipment, and move the work equipment into the danger area.
And a controller that calculates the speed signal according to the work machine speed.
Pilot a lock valve that changes the speed reduction rate of the work machine
Operated by hydraulic pump and supply of discharge oil from this hydraulic pressure
Installed in the circuit between the pilot pressure control valve
And the output signal of the controller
Working machine interference prevention circuit, characterized in that a proportional electromagnetic relief valve Ru changing the set pressure.