JPH026079Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention is used for a winch as a construction machine or a winch for a crane truck.

<Prior Art> A winch or a winch mounted on a crane truck rotates a drum using a hydraulic motor or the like, and winds or unwinds a wire rope around this drum to raise or lower a suspended load. Some winch drums are equipped with a negative brake device and a drum lock device. The circuit of such a conventional winch is shown in FIG. The winch drum 1 and the hydraulic motor 2 are connected and disconnected by a clutch device 3. When the hydraulic motor 2 and the drum 1 of the winch 2 are disconnected by the clutch device 3, the negative brake device 4 and the drum lock device 5 act to prevent the load from falling freely.

The clutch device 3 connects the output shaft 2a of the hydraulic motor 2 and the winch drum 1 by supplying pressure oil to the clutch cylinder 3a, and when the pressure oil is discharged, the clutch cylinder 3a is compressed by a spring and the output shaft 2a is connected to the clutch cylinder 3a. and the winch drum 1.

In the negative brake device 4, the brake cylinder 4a has a spring 4b inside, and when pressure oil is supplied to one chamber 4c, the brake shoe 4d is separated from the circumferential surface of the winch drum 1 and the braking force is reduced. When the pressure oil is discharged, the brake shoe 4d is pressed against the circumferential surface of the winch drum by the spring 4b, and the brake is applied.

The drum lock device 5 is equipped with a latch at the tip of a hydraulic cylinder similar to the negative brake device 4, and when the pressure oil is discharged, the latch is inserted into the teeth provided on the drum by the force of a spring and locked. When supplied, the lock is released.

The negative brake device 4 and drum lock device 5 of this conventional winch are operated as independent systems, and their operation is left to the operator.

<Problems to be Solved by the Invention> When operating the winch, it is necessary to first release the locked state of the drum lock device 5 and then release the negative brake device 4. If this is not done, the drum and the hydraulic motor will be connected while the drum locking device remains locked, and both the load and the lowering power load may be applied to the drum locking device. As a result, the drum lock device would be damaged, resulting in the problem of damage due to erroneous operation.

<Means for solving the problem> The means of this invention is a negative brake that has a spring that applies force to the braking side of a drum driven by a hydraulic motor, and a brake cylinder that operates on the side that releases the braking by supplying pressure oil. and a lock device having a spring that applies force to the side that locks the drum and a lock cylinder that operates to the side that releases the lock by supplying pressurized oil, the winch comprising: a circuit that supplies pressurized oil to the brake cylinder; , a low pressure selection valve is provided between the circuit that supplies pressure oil to the lock cylinder and connects the circuit with lower hydraulic pressure of both circuits to the brake cylinder, and the spring force of the negative brake device is This is because the spring force is greater than that of the locking device.

<Operation> According to the means of this invention, the brake cylinder of the negative brake device is supplied with pressurized oil from either the circuit that supplies pressurized oil to the brake cylinder or the circuit that supplies pressurized oil to the lock cylinder, whichever has a lower pressure. is supplied. Furthermore, since the spring force of the negative brake device is greater than the spring force of the lock device, when the pressure oil is supplied to the lock cylinder and the brake cylinder, the lock cylinder first operates to release the lock. , then the brake cylinder operates to release the brake.

Also, when the pressure oil in both circuits is equal,
Low pressure selection etc. are not switched, but in this case as well, because there is a difference in the spring force between the two devices mentioned above, the lock cylinder operates to release the lock, and then the brake cylinder operates to release the brake. .

<Example of actual distribution> Fig. 1 shows a circuit showing an embodiment of this invention, where 1 is a drum of a winch, and 2 is a hydraulic motor that rotates the drum. 3 is a clutch device, which connects the output shaft 2a of the hydraulic motor 2 and the drum 1 when pressure oil is supplied to the chamber 3b of the clutch cylinder 3a via the hydraulic circuit 3c, and discharges the pressure oil from the chamber 3b. Then, the connection between the hydraulic motor 2 and the drum 1 is severed. Note that 3d in the figure is a swivel joint.

4 is a negative brake device, and when pressure oil is supplied to the chamber 4c of the brake cylinder 4a in which the spring 4b resides, the piston of the brake cylinder 4a is moved against the spring 4b, and the brake shoe 4 is moved.
d away from the surface of the winch drum 1 to release the brake force. When the pressure oil in the chamber 4c is discharged, the piston of the brake cylinder 4a is pressed by the spring 4b, and the brake shoe 4d is pressed against the surface of the drum 1, thereby applying the brake to the drum 1.

The drum lock device 5 includes a lock cylinder 5 equipped with a spring 5b similar to the brake cylinder 4a.
A is adapted to insert and remove a pawl between teeth provided on a predetermined peripheral surface of the drum 1, and when pressure oil is supplied to the chamber 5c of the lock cylinder 5a, the piston retreats against the spring 5b. , the lock is released by pulling the claw out from between the teeth. When the pressure oil in the chamber 5c is discharged, a pawl is inserted between the teeth provided on the drum by the spring 5b, and the drum 1 is locked.

Reference numeral 5e designates a lock circuit having a switching valve 7 for locking and unlocking the drum locking device, and operation of the switching valve 7 controls supply and discharge of pressure oil to the lock cylinder 5a.

4e and 4f are brake circuits for negative brake operation, which are turned on and off by the low pressure selection valve 6.

The low pressure selection valve 6 has a neutral position 6a and a switching position 6.
b and 6c, and when there is a hydraulic pressure difference between the lock circuit 5e and the brake circuit 4f, the switch is switched to the switching position 6b or 6c, and when there is no hydraulic pressure difference, it is held at the neutral position 6a.

6h and 6i are slow return check valves provided to reliably switch the low pressure selection valve 6. Further, the spring force of the spring 4b is made larger than that of the spring 5b.

Although not shown, the clutch device 3 and the negative brake device 4 are interlocked, and the "fitting" state in which the clutch device 3 is connected to the output shaft 2a and the drum 1 and the braking force of the negative brake device 4 are controlled. The release and release of the suspended load are sufficiently equalized so that the holding power of the suspended load is not lost.

In FIG. 1, if pressure oil is not supplied to each cylinder of the clutch device 3, brake device 4, and lock device 5, the drum 1 is separated from the output shaft 2a of the hydraulic motor 2, and the negative brake device 4 is separated from the output shaft 2a of the hydraulic motor 2. and a locking device 3 to stop the lifting load against the load.

Next, when pressure oil is being supplied to the lock circuit 5e by operating the switching valve 7 and to the brake circuit 4f by other operations, when the oil pressure in the lock circuit 5e decreases due to the oil pressure in the brake circuit 4f, the low pressure selection valve 6 is switched to the switching position 6c, the brake cylinder 4a and the lock cylinder 5a are connected to the lock circuit, and a slow return check valve 6h is connected between the brake cylinder 4a and the lock circuit 5e.
Connect via. Therefore, the lock cylinder 5a first operates to release the lock, and then the brake cylinder 4a operates to release the brake.

Further, when the hydraulic pressure of the brake circuit is lowered by the lock circuit 5e, the low pressure selection valve 6 is switched to the switching position 6b, and the brake cylinder 4a and the brake circuit 4 are switched to the switching position 6b.
Connect to f. Therefore, in this case as well, the operation of the brake cylinder 4a is delayed from that of the lock cylinder 5a.

<Effects of the invention> According to this invention, the order of operation of the lock cylinder and the brake cylinder is reliably determined, thereby preventing damage to the winch drum locking device due to erroneous operation.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the general structure of an embodiment of this invention, and FIG. 2 is a circuit diagram of a conventional winch. 1...Winch drum, 2...Hydraulic motor,
3...Clutch device, 4...Negative brake device, 5...Drum lock device, 6...Low pressure selection valve, 7...Switching valve.

Claims (1)

[Scope of utility model registration request] A negative brake device includes a spring that applies force to the side that brakes a drum driven by a hydraulic motor, and a brake cylinder that operates to the side that releases the brake by supplying pressure oil, and a spring and pressure that applies force to the side that locks the drum. In a winch equipped with a lock device having a lock cylinder that operates on the side that releases the lock by oil supply, between a circuit that supplies pressure oil to the brake cylinder and a circuit that supplies pressure oil to the lock cylinder, A winch brake characterized in that a low pressure selection valve is provided to connect the circuit with lower hydraulic pressure of both circuits to the brake cylinder, and the spring force of the negative brake device is made larger than the spring force of the lock device. Tuning circuit between the device and the drum lock device.