JPS641348Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a clutch control device for a hydraulic winch. In hydraulic winches used for crane trucks and the like, in order to improve work efficiency, a clutch is provided between the winch drum and the drive device to allow the hanging hook to fall freely. However, in the past, the clutch could be disengaged regardless of whether or not a load was suspended using the hoisting hook, so there was a risk that the hoisted load would fall if the clutch was accidentally disengaged with the load suspended. It was hot.

The present invention was developed in view of the above circumstances, and includes a suspended load detector that detects whether or not a load is suspended, and a clutch that selectively connects the clutch cylinder and the pressure oil supply pipe or return pipe. a switching valve;
The hydraulic winch is equipped with a shut-off valve that is inserted into the return pipe and is activated by a signal from the suspended load detector, so that the clutch will not be disconnected even if it malfunctions while a load is suspended. The object of the present invention is to provide a clutch control device.

Embodiments of the present invention will be described below with reference to the drawings. The discharge pipe 4 of the pump 2 is connected to a switching valve 5, and the switching valve 5 and the base rotation motor 6 are connected by pipes 7 and 8, and when the switching valve 5 is operated, the motor 6 is rotated in forward and reverse directions. The carryover pipe 9 of the switching valve 5 is connected to the switching valve 11 via the check valve 10, and the switching valve 11 and the winch drive motor 15 are connected through the pipes 12 and 13. Reverse. 14 is a counterbalance valve, and 16 is a pressure switch provided between the motor 15 and the counterbalance valve, which is activated by the pressure generated between the motor 15 and the counterbalance valve 14 when a load is lifted by a winch, and When no load is being lifted, the operation is canceled and it functions as a suspended load detector.

The discharge pipe 18 of the pump 3 is connected to a switching valve 19, the switching valve 19 and the outrigger cylinder 22 are connected by pipes 20, 21, and the cylinder 22 expands and contracts by operating the switching valve 19. The carryover line 23 of the switching valve 19 is branched, and one line is connected to the clutch switching valve 26 via a check valve 24 and a pressure oil supply line 34, and between the check valve 24 and the clutch switching valve 26, is connected to an accumulator 25. The clutch switching valve 26 and the clutch cylinder 27 are connected by a pipe 28, and the return pipe 29 of the clutch switching valve 26 is connected to the reservoir 1 via an electromagnetic shut-off valve 30. It is operated by a pressure switch 16 which is a pressure switch. The other branched pipe is connected to the pump 2 via the unload valve 31.
The pilot line 33 of the unload valve 31 is connected to the carryover line 9 between the check valve 10 and the switching valve 11 on the side, and the pilot line 33 of the unload valve 31 is connected to the accumulator 25. The valve 31 is in a cutoff state, and the oil discharged from the pump 3 is transferred to the accumulator 2.
When the pressure in the accumulator 25 reaches the cut-out pressure, the unload valve 31 becomes in communication, and the oil discharged from the pump 3 is sent to the carryover pipe 9, and when the pressure in the accumulator 25 drops to the cut-in pressure. The unload valve 31 enters the cutoff state, and the pressure is accumulated in the accumulator 25 again.

With the above configuration, when no load is suspended, pressure above a certain level does not occur in the pipeline between the motor 15 and the counterbalance valve 14, so the pressure switch 16 does not operate, and therefore the electromagnetic shut-off valve 30 is held at the d position shown in the figure, and the clutch switching valve 26 and the reservoir 1 are in communication, so if the clutch switching valve 26 is set to the close position a, pressure oil is supplied to the clutch cylinder 27 and the clutch is engaged. When this state is maintained and the clutch switching valve 26 is switched to the disengaged position b, the clutch cylinder 27 communicates with the reservoir 1, the clutch becomes disengaged, and the hanging hook falls freely.

When a load is suspended, a pressure above a certain level is generated in the line between the motor 15 and the counterbalance valve 14, so the pressure switch 16 is activated and the electromagnetic shut-off valve 30 is switched to position c, and the clutch switching valve is activated. 26 and reservoir 1 are shut off. Therefore, even if the clutch switching valve 26 is accidentally switched to the disengaged position b, the clutch cylinder 27 will not communicate with the reservoir 1, so the clutch will not be disengaged and the suspended load will not fall.

As described above, the present invention provides a clutch control device for a hydraulic winch that has a simple structure and does not cause the clutch to disengage even if the clutch is operated incorrectly while a load is suspended, thereby improving the safety of cranes. It is effective for

[Brief explanation of drawings]

FIG. 1 is a partially omitted circuit diagram showing an embodiment of the present invention. 16...Pressure switch (hanging load detector), 26...
...Clutch switching valve, 27...Clutch cylinder,
29...Return pipe line, 30...Electromagnetic shut-off valve, 34...Pressure oil supply pipe line.

Claims (1)

[Scope of utility model registration request] a suspended load detector for detecting whether a load is suspended; a clutch switching valve for selectively connecting the clutch cylinder and a pressure oil supply line or a return line; A clutch control device for a hydraulic winch, characterized in that it is equipped with a shutoff valve that is operated by a signal from a hydraulic winch.