JP2996761B2 - Work machine interference prevention circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work machine interference prevention circuit for preventing a work machine from interfering with a driver's cab at the time of work in a vehicle for excavation loading such as a power shovel.

[0002]

2. Description of the Related Art In an excavation loading vehicle such as a power shovel, a work machine including a boom, an arm, a bucket, and the like is generally provided on an upper swing body. The arm provided at the tip of the boom and the bucket at the tip of the boom are configured to rotate in the front-rear direction, so that they do not interfere with the driver's cab provided at the upper part of the upper revolving unit. . 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 an excavation loading vehicle having such a mechanism, when the upper boom is offset to the cab side, the working range of the arms and buckets includes an area 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.In the case of automatic stop, the circuit with the pilot hydraulic pump supplied to the pilot pressure control valve to be operated In this case, the two-position switching valve provided in the vehicle is switched to the direction in which the drain is drained, and the automatic stop is suddenly performed at 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.

[0004] In view of this, the present invention reduces the speed according to the speed of the work machine when the bucket enters a predetermined range before the automatic stop rather than the sudden stop when the vehicle enters the interference 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 rate to solve the drawbacks of the prior art.

[0005]

The present invention as means for solving the problems of the prior art SUMMARY OF THE INVENTION, the first boom undulating, second boom offset to the left and right, the working machine having an arm and a bucket or the like moves up and down In an excavation loading vehicle mounted so as to be able to perform a bending work motion toward the cab after being offset to the front side of the cab, between the pilot hydraulic pump and the pilot pressure control valve that operates the work machine. Input the signals from the potentiometers that detect the boom angle, arm angle, and offset angle to the circuit to determine that the work equipment 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.
Characterized in that a proportional solenoid valve which Ru changing the lower rate.

[0006]

According to the above construction, the circuit pressure reaching the downstream pilot pressure control valve is controlled by the electromagnetic proportional valve, whereby the speed of the working machine is changed.

[0007]

DETAILED DESCRIPTION FIG. 1 is an illustration of an example of a working machine interference preventing circuit that involved 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.

The excavation loading vehicle 1 to which the present invention is applied is provided with a lower traveling body 15 as shown in FIGS. 2 and 3, and an upper revolving body 16 is provided on the lower traveling body 15 so as to be pivotable. ing. The base end of the first boom 2 is mounted on the upper revolving unit 16, and the first boom 2 can be raised and lowered by a boom cylinder 17. At the tip of the first boom 2, a second boom 3 is provided with an offset cylinder 18 in the left-right direction.
The third boom 19 is attached to the tip of the second boom 3 so as to be vertically movable. The arm 4 is rotatable vertically by an arm cylinder 20 at the tip of the third boom 19, and the bucket 5 can be loaded and dumped by a bucket cylinder 21 provided on the arm 4. First boom 2
Boom angle to detect the position of the first boom 2 on the base side surface of
Boom potentiometer 1 as a sensor for α detection
0 is mounted on the third boom 19, and an arm potentiometer 11 as a sensor for detecting an arm angle β for detecting the position of the arm 4 is mounted on the third boom 19; An offset potentiometer 12 as a sensor for detecting an offset angle γ for detecting an offset amount of the boom 3 is mounted. Figure
Reference numeral 6 denotes an operator cab provided on the upper swing body 16.

FIG. 1 shows a main part of the present invention. A circuit 9 between a pilot hydraulic pump 7 and a pilot pressure control valve 8 which is operated by supplying a discharge oil from the hydraulic pump 7 is electromagnetically proportional. A valve 14 is provided, and the valve 14 is connected to signals 22, 2 from potentiometers 10, 11, 12.
These are connected to the output signal 25 of the controller 13 which receives and calculates 3 and 24. In the figure, 26 is a relief valve,
27 is a tank.

Next, the operation will be described. By operating each operating lever (not shown) of the pilot pressure control valve 8,
Each part of the work machine is operated, and the boom cylinder 17, the arm cylinder 20, and the offset cylinder 18 expand and contract, and the first boom 2, the arm 4, and the second boom 3 operate. The position of the first boom 2 is detected by the boom potentiometer 10 when the first boom 2 rotates. The position of the arm 4 is detected by the arm potentiometer 11 when the arm 4 rotates. Similarly, the offset amount of the second boom 3 is detected by the offset potentiometer 12 when the second boom 3 rotates. Each potentiometer 10,1
The signals detected by 1 and 12 are input to the controller 13. The controller 13 determines whether or not the bucket 5 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 γ signals from the potentiometers to determine the speed. The output signal 25 is sent to the electromagnetic proportional valve 14 by changing the speed reduction rate according to the speed of the work machine as a signal and reducing the speed. As a result, the electromagnetic proportional valve 14 gradually reduces the supply of the oil discharged from the pilot hydraulic pump 7 to the pilot pressure control valve 8 and finally drains the oil to the tank 27. As a result, the working machine is automatically stopped, but the shock at the time of stopping is reduced.

[0011]

As described above, according to the present invention, a work machine including a first boom that rises and falls, a second boom that offsets left and right, an arm and a bucket that moves up and down, etc. In addition, in an excavation loading vehicle mounted to be able to perform a bending work movement toward the cab,
A signal from each potentiometer for detecting a boom angle, an arm angle and an offset angle of the working machine is input to a circuit between a pilot hydraulic pump and a pilot pressure control valve for operating the working machine. Dangerous area
Judging that the vehicle has entered the range, the speed signal according to the work machine speed
A controller for calculating a, because provided an electromagnetic proportional valve Ru changing the speed reduction ratio of the working machine by the output signal from the controller, from the front to rapidly automatically stopped upon entering the working range of the bucket is determined gradually It is possible to stop the working speed, and therefore, it is possible to significantly reduce the shock generated as compared with the conventional case in which the operation speed is automatically stopped suddenly.

[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: Excavation loading vehicle, 2: First boom, 3: Second boom,
4: arm, 5: bucket, 6: cab, 7: pilot hydraulic pump, 8: pilot pressure control valve, 9:
Circuits 10 to 12 : potentiometer, 13: controller, 14: solenoid proportional valve, α: boom angle, β: arm angle, γ: offset angle.

Claims (1)

(57) [Claims] 1. A work machine having a first boom that rises and falls, a second boom that offsets left and right, an arm that moves up and down, a bucket, and the like, is offset to the front side of a cab,
In a vehicle for excavation loading mounted so as to be able to perform a bending work motion toward a cab, a boom angle, an arm angle, and an offset angle are provided in a circuit between a pilot hydraulic pump and a pilot pressure control valve that operates a work machine. if the input signal from the potentiometer to detect, working machine interference
Judge that you have entered the danger area, and according to the work machine speed
A controller that calculates the speed signal is provided.
Working machine interference prevention circuit, characterized in that a proportional solenoid valve which Ru changing the speed reduction ratio of the working machine by the output signal from the.