JPH0745655Y2 - Locking device for hydraulic excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a construction machine, in particular, a hydraulically driven running machine and a working machine in which a boom, an arm, a bucket, etc. are jointly connected to each other to lift the soil and sand by the weight of the construction machine. The present invention relates to a lock device for a hydraulic excavator that can descend.

(Prior Art) As shown in FIG. 3, a hydraulic excavator normally has a traveling body 3 driven by a hydraulic motor 2 at a lower portion of a vehicle body 1, and a boom 5 as a working machine 4 at a front portion of an upper rotatable body. , Arm 6,
The bucket 7 is articulated, and the hydraulic cylinders 8, 9,
At 10, it moves up and down for excavating and loading earth and sand. The hydraulic actuators such as the hydraulic cylinders for the traveling motor working machine are adapted to supply the discharge hydraulic pressure from the hydraulic pump through the manual operation of each operating valve or the pilot operation, and therefore, the hydraulic actuator is lifted upward. The machine can be lowered by its own weight, and even if the engine is stopped for work suspension, it can be lowered by its own weight unless the operating valve is opened unless it is fully lowered and grounded. There is a danger that an operator or an outsider may accidentally touch the operation lever to cause a runaway, or the working machine may drop to cause a personal injury.

Therefore, conventionally, there is provided a lock device that prevents the operation valve from opening even if these operation levers are touched by mistake.
The figure is an example thereof, and as shown, the discharge circuits 13a, 1 of the two hydraulic pumps 12a, 12b driven by the engine 11 are shown.
3b are connected to respective operation valve groups 14a and 14b for controlling traveling, turning and actuators of the working machine, and these operation valves operate a pilot circuit 17 by a pilot oil pressure from a pilot pump 16 by an operation lever 15. It is designed to be controlled by switching. A lock valve 18 is provided in the pilot circuit 17 of the pilot pump 16 in order to lock the actuator via each of these operation valves, and the opening / closing valve 18 supports the driver's seat 19. Lock lever installed at the front of the entrance side at 20
21 is connected via a mechanical linkage 22 and the lock lever 22 is operated in the vertical direction as shown in the drawing so that the pilot valve 17 is closed or communicated by the lock valve 18 and the operator operates. When leaving the car for a while, the pilot circuit is shut off and the operating valves 14a and 14b for traveling, turning, and working equipment etc. are completely locked, and even if the operating lever is touched, the operating valve will operate incorrectly. Therefore, it is designed so that it will not run out of control and the working machine will not drop by its own weight. Reference numeral 23 denotes an accumulator, which is provided for hydraulic pressure for operation when it is desired to temporarily move the work implement even after locking.

(Problems to be solved by the invention) However, if the operator forgets to lock the lock device, no effect can be expected, and the lock lever is provided near the driver's seat so that the operator does not forget to lock the lock device. There was a risk that the lever would get in the way when getting in and out, and even if the foot hits it, it may fall.

The present invention aims to solve the problems of the conventional locking device (means and action for solving the problem). The present invention has been made to achieve the above-mentioned object. A lock device for a hydraulic excavator according to the present invention comprises an engine 31 and a hydraulic pump 32 driven by the engine 31.
a, 32b and the pilot pump 35, and a proportional control valve 37a, which outputs pilot pressure according to the operation amount of the operating means 36a, 36b,
37b and the operating valve 34a, which supplies and discharges pressure oil from the hydraulic pumps 32a, 32b to and from the actuator, and is switched by pilot pressure.
34b, a detecting means 40 for detecting a non-operating state of the operating means 36a, 36b, and a pilot circuit 41 for supplying pilot pressure from the pilot pump 35 to the operating valves 34a, 34b via the proportional control valves 37a, 37b. All the operating means 36a, 36
In a lock device for a hydraulic excavator, which includes a lock valve 42 that shuts off the pilot circuit 41 by receiving a detection signal that b is in a non-operating state, a lock release means 45 that releases the locked state of the lock valve 42. .

A delay unit 44 may be provided between the detection unit 40 and the lock valve 42 to transmit the detection signal to the lock valve 42 after a predetermined time has elapsed after receiving the detection signal.

A lock device for a hydraulic excavator according to a second aspect of the present invention is the same as the lock device for a hydraulic excavator according to the first aspect, wherein the detecting means is an operator instead of the detecting means 40 for detecting the non-operating state of the operating means. A lock release means 54 for releasing the lock state of the lock valve 42 is provided with a detection means 48 for detecting the leaving of the seat.
It consists of.

In the case of the above configuration, the operation is as follows.

The lock device of the hydraulic excavator according to the first invention operates all the operation means 36a, 36b when the operation means 36a, 36b are operated in a non-operation state in order to temporarily suspend the work such as a break of the operator. Detecting that the means 36a and 36b are in the non-operation state 4
When detected by 0, the detection signal is output to the lock valve 42 and the lock valve 42 shuts off the pilot circuit 41.
Therefore, unless the lock release means 45 is operated to release the blocking of the pilot circuit 41 by the lock valve 42, the operation means 36
Since the pilot pressure is not supplied to the operation valves 34a and 34b even if the valves a and 36b are operated, the actuator does not operate. Next, when working, if the lock release means 45 is operated to release the blocking of the pilot circuit 41 by the lock valve 42, pilot pressure corresponding to the operation amount of the operation means 36a, 36b is supplied to the operation valves 34a, 34b. Therefore, the actuator can be operated.

The detection signal detected by the detection means 40 is delayed by the delay means 44.
Is output to the lock valve 42 after a predetermined time, the lock valve 42 causes the pilot circuit 41 to operate when the work is temporarily stopped during the operation instead of the work stop for a predetermined time or longer, such as when the operator rests. It never shuts off.

A lock device for a hydraulic excavator according to a second aspect of the present invention is the lock device for a hydraulic excavator according to the first aspect, in which a detecting means 48 for detecting the leaving of the operator is installed in place of the detecting means 40. , Another lock releasing means 54 is installed in place of the lock releasing means 45, the pilot signal 41 is cut off by the lock valve 42 inputting the detection signal of the detecting means 48, and the lock releasing means 54 locks the lock valve. 42 is unlocked. Claim 1 for other effects.
(Embodiment) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a hydraulic control circuit of a hydraulic excavator, which includes two hydraulic pumps 32 driven by an engine 31.
The discharge circuits 33a and 33b of a and 32b are connected to operation valve groups 34a and 34b for controlling the traveling motor, the swing and the actuators of the working machine. The actuator operating valve groups 34a and 34b are switch-controlled by the pilot hydraulic pressure of the pilot pump 35 via the operating levers 36a and 36b. These operating levers are provided with proportional control valves (PPC valves) 37a and 37b, respectively.
Apply pressure oil corresponding to the operation amount of 36b to the pilot circuits 38a, 38b.
It is configured to be sent to each of the control valve groups 34a and 34b through the switch for switching control. In the hydraulic control circuit as described above, in order to disable the switching control of each operation valve 34a, 34b by operating each operation lever 36a, 36b, the proportional control valve 37a, 37b
In addition to outputting the pressure oil according to the operation amount of the shuttle valve 39, a hydraulic switch 40 that is turned on and off by the shuttle valve is provided, and when the shuttle valve 38 outputs the pressure oil, That is, when any one of the operation levers 36a and 36b is operated, the pressure oil causes an OFF operation. On the other hand, the pilot oil passage 41 is provided with an electromagnetic lock valve 42 for opening and closing the circuit, and the lock valve 42 is provided with an electric signal circuit 43 from the electrohydraulic switch 40.
When the hydraulic switch 40 is turned on, the lock valve 42 closes the pilot oil passage 41 and communicates by turning it off. A timer 44 and a lock release switch 45 are provided in the operation electric circuit 43 of the lock valve 42. Next, the operation of the lock device configured as described above will be explained.
When 36a and 36b are in the non-operating state, that is, neutral, the proportional control valve
The output of pressure oil from 37a and 37b disappears, the shuttle valve 39 turns on, and then the hydraulic switch 40 turns on. The ON signal of the hydraulic switch 40 is transmitted to the lock valve 42, which closes the pilot oil passage 41 so that the pilot pressure is proportional to the proportional control valve 37.
If it is not sent to a and 37b, there is no pilot pressure even if the operating levers 36a and 36b are operated thereafter, and the operating valve groups 34a and 34b
Cannot be switched and the actuator of the traveling work machine etc. is completely locked. However, the operating levers 36a, 36b
It becomes a problem that it will be locked immediately even if it becomes a non-operation state.Because it is necessary to check after a while whether it is a non-operation state for work suspension, it is necessary to lock for the first time The delay time is set.

Further, since the work is restarted, even if the operation lever is moved to the operation state, the pilot hydraulic pressure is locked and the operation cannot be performed. Therefore, a switch 45 for unlocking is provided, and by turning on the unlocking switch, the lock valve 42 is turned off and the pilot oil passage 41 is opened. FIG. 2 shows another embodiment of the present invention, in which the hydraulic control circuit is the same as that of the above-mentioned embodiment, and this embodiment also closes the pilot oil passage 41. A lock device, more specifically, a proximity switch 48 is mounted on the front surface of a pedestal 47a on the entrance / exit side of the driver's seat 46, and the electromagnetic lock valve 42 is opened / closed from this proximity switch by an electric circuit 49 shown in the figure. It is designed to work. Note that 50 is a relay, 51 and 52 are switches, and 53 is a power source, and this electric circuit itself is a circuit that is normally used. Therefore, when the operator pauses work and crosses the front of the driver's seat 46 when leaving the operator's cab, the proximity switch 48 detects and the lock valve 42 is turned on by the electric circuit to close the pilot oil passage 41. Disable the control valve groups 34a, 34b. And when the work is restarted, the pedestal 47b on the opposite side of the driver's seat
When the release switch 54 attached to the switch is turned on, the lock valve 42 is turned off, the pilot circuit 38 is communicated, and the operation lever 36 is operated so that the operation valve groups 34a and 34b can be switched and controlled. Become.

(Effects of the Invention) Since the present invention is configured as described above, (1) all the operating means 36a, 36b such as traveling and working equipment are in a non-operating state, and this is a temporary work suspension during the operation. When it is judged that the condition is not met, the operation valve 3 operated by each operation means 36a, 36b
When the operation of 4a, 34b is automatically locked, or the operator leaves the seat, the lock valve 42 is used to operate the pilot circuit.
41 is shut off, and the operating valves 34a, 34b by the respective operating means 36a, 36b
The operation of is automatically locked. Therefore, it is possible to omit the troublesome operation of locking the operation means 36a and 36b again.

(2) Further, since the unexpected operation of the operating means 36a, 36b due to forgetting to lock the operating means 36a, 36b is prevented, the operation valve 34
The danger of abruptly operating a, 34b is prevented,
The safety can be improved.

(3) When the work is restarted, the lock state of the lock valve 42 is simply released by simply operating the lock release means 45 or 54, and the operation valves 34a, 34b are operated by the respective operation means 36a, 36b.
As a result, the operability can be improved, and unless the operator intentionally operates the unlocking means 45 or 54, the operation of the operating valves 34a, 34b by the operating means 36a, 36b is locked, further improving safety. Can be improved.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of a hydraulic excavator showing an embodiment of the present invention, FIG. 2 is a control circuit diagram showing another embodiment of the present invention, and FIG. 3 is a schematic side view showing a hydraulic excavator. FIG. 4 is a control circuit diagram showing an example of a lock device for a conventional hydraulic excavator. 34a, 34b …… Operating valve group 35 …… Pilot pump 36 …… Operating lever 37 …… Proportional control valve 38a, 38b …… Pilot circuit 39 …… Shuttle valve 40 …… Hydraulic switch 41 …… Pilot oil passage 42 …… Lock valve 44 …… Timer 45 …… Release switch 48 …… Proximity switch 54 …… Release switch

Claims (3)

[Scope of utility model registration request] 1. An engine 31, hydraulic pumps 32a, 32b and a pilot pump 35 driven by the engine 31, and proportional control valves 37a, 37b for outputting a pilot pressure according to an operation amount of operating means 36a, 36b. , Operating valves 34a, 34b for supplying / discharging pressure oil from the hydraulic pumps 32a, 32b to the actuator and switching by pilot pressure, detecting means 40 for detecting a non-operating state of operating means 36a, 36b, and pilot pump 35 Pilot pressure from the control valves 34a, 34b via the proportional control valves 37a, 37b.
The lock of the hydraulic excavator, which is installed in the pilot circuit 41 for supplying to the control circuit and also includes a lock valve 42 that shuts off the pilot circuit 41 by receiving a detection signal in which all the operating means 36a and 36b are in the non-operating state. In the device, a lock device for a hydraulic excavator, characterized by comprising lock releasing means 45 for releasing the locked state of the lock valve 42. 2. A delay means 44 for transmitting the detection signal to the lock valve 42 after a predetermined time has elapsed after receiving the detection signal, is provided between the detection means 40 and the lock valve 42. A lock device for a hydraulic excavator according to item (1). 3. A lock device for a hydraulic excavator according to claim 1, wherein the detecting means is a detecting means 48 for detecting the leaving of the operator instead of the detecting means 40 for detecting the non-operating state of the operating means. A lock device for a hydraulic excavator characterized by being installed.