JPH0158120B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a clutch and brake control circuit for a hydraulic crane winch.

In the case of a hydraulic crane winch in which the winch drum is rotationally driven by a hydraulic drive means that combines a hydraulic pump and a hydraulic motor, a hydraulically actuated clutch that intermittently transmits rotational power from the hydraulic motor to the winch drum, and a winch. It is usually equipped with a brake mechanism to prevent the drum from idling.

The aforementioned hydraulic clutch is intermittently operated by pressure fluid selectively directed by a control valve separate from the control valve that controls the rotational direction of the hydraulic motor, and the brake mechanism is a positive brake mechanism that artificially applies braking. There is also a negative brake mechanism that automatically exerts a braking action when the hydraulic clutch is disengaged or when the hydraulic motor is in neutral.
The former brake mechanism has a safety problem because it is necessary to manually apply the brake and lock the brake when the hydraulically actuated clutch is disconnected to stop the rotation of the winch drum. On the other hand, when the hydraulic clutch is disconnected and the winch drum is idling, the lowering braking can be controlled manually when lifting equipment or suspended loads are being freely lowered, which has the advantage of being able to stop slowly and stop at an accurate position. be. Unlike the positive brake mechanism described above, the latter brake mechanism is superior in terms of safety because it automatically brakes. On the other hand, when free-lowering a hanging device or a suspended load, it is necessary to release the brake.
Send hydraulic pressure to the brake release cylinder and turn it on.
The idling of the winch drum is controlled by reducing the spring force in the OFF state, but there is a time lag in controlling the release of the braking force due to the hydraulic pressure, making it difficult to release the brake slowly and making it difficult to stop at an accurate descending position.

Furthermore, the conventional winch control mechanism has forward, reverse and neutral control levers for a hydraulic motor, ON and OFF levers for a hydraulic clutch, and a brake actuation or brake release pedal. It is being operated. In such cases, it is easy to make incorrect operations, and winch operation requires skill. For example, in the conventional case, when lifting equipment or a suspended load, when the clutch is turned off, if the brake pedal is not pressed in conjunction with the brake pedal, it will drop rapidly and become dangerous (in the case of a winch with a positive brake mechanism). Depress the brake release pedal first, then press the clutch ON/OFF lever later.
An incorrect operating procedure for free-fall control that turns OFF can also lead to rapid descent, which is dangerous (in the case of winches with a negative brake mechanism).Furthermore, operating the hydraulic motor without checking that the clutch ON and OFF levers are in the ON position is dangerous. Unexpected movements of the hanging equipment or load may occur due to lever operation.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a control device that allows winch operations such as hoisting, lowering, brake locking, and free fall operations to be obtained by single operation control. It is something to do.

Another object of the present invention is to provide a control device that is equipped with a pair of negative brake mechanism and positive brake mechanism so that a positive brake can be applied only during a free fall operation.

Hereinafter, explanation will be given by way of example. Reference numerals 10 and 11 indicate a pair of winch drums, and 12 and 1 comprehensively indicate a pair of winch drums.
It is equipped with a clutch/brake hydraulic control circuit shown at 3. The hydraulic control circuits 12 and 13 have the same configuration, and hereinafter, components having the same configuration will be given the same reference numerals and their functions will be explained. Although the embodiment shows two winch drums, it goes without saying that the hydraulic control circuit works even in the case of one winch drum.

The hydraulic control circuit 12 (including 13) introduces pressure fluid from two hydraulic sources, one of which is a hydraulic pump 15 that discharges the driving pressure fluid for the hydraulic motor via the connection circuit 14, The other one is the accumulator 17 via the connection circuit 16.
(This is not necessarily limited, and in the case of a truck crane, other pumps can be used as the pressure source). The connecting circuits 14, 16 are selectively connected to and disconnected from the clutch/brake control circuits 19, 20 by means of a switching valve 18, and the one circuit 19 for controlling the discharge of the circuits 19, 20 is connected to a drum rotary clutch. 21 , and the other circuit 20 communicates with a brake release cylinder 22 . The A position of the switching valve 18 is connected to the connection circuit 14, the control circuit 20, and the connection circuit 1.
6 and the control circuit 19 are communicated with each other.

Therefore, the accumulator 1 of the second hydraulic pressure source
Pressure fluid from control circuit 19 compresses drum rotation clutch 21, causing the winch drum to rotate.

At the same time, the hydraulic pump 15 as the first hydraulic power source rotates the hydraulic motor 24 via the rotation direction switching valve 23 of the hydraulic motor, rotates the winch drum through the power transmission shaft 25, and connects the connection circuit 14 through the shuttle valve 26. Motor rotation driving pressure fluid is supplied to the control circuit 20 and enters the brake release cylinder 22 to compress the brake spring 27 and release the brake.

The A position of the switching valve 18 allows the winch drum to be hoisted and lowered, and it operates regardless of whether the rotation direction switching valve 23 of the hydraulic motor is in the normal or reverse position. Note that when the switching valve 23 is set to neutral, the hydraulic motor 24 is not driven, and the connection circuit 1
Since no pressure fluid is supplied to 4, the brake is activated and is safe.

The B position of the switching valve 18 cuts off communication between the connection circuits 16 and 14 to the control circuits 20 and 19, and the control circuit 2
Set 0,19 to discharge.

Accordingly, the rotary clutch 21 is disengaged, the fluid in the cylinder 27 is also discharged, and the brake is applied to keep the hanging tool or load suspended in the air.

The C position of the switching valve 18 allows communication between the connection circuit 16 and the control circuit 20 and blocks communication between the connection circuit 14 and the control circuit 19. This means that the rotating clutch 21
The brake is controlled to be released, and the winch drum is idled to obtain a free descent.

In a winch device that employs a conventional negative brake mechanism, when the rotary clutch is disengaged, the flow of pressure fluid for driving the rotation of the hydraulic motor into the brake release cylinder is cut off, resulting in automatic braking.

In the present invention, since the pressure of the second hydraulic pressure source is guided from the control circuit 16 to the brake release cylinder 20, there is no automatic braking action, and therefore the brake can be applied positively only during free fall. Positive brake mechanism 2
8 is replaced with a negative brake mechanism 29 to exert a braking action.

Since the present invention is configured as described above, the winch operation can be switched using a single switching valve, and the risk of erroneous operation can be reduced compared to the conventional method. Furthermore, even when operating a two-drum winch, it is easier to operate a single switching valve than in the past.

[Brief explanation of drawings]

The drawing is a circuit diagram showing an embodiment of the present invention. 15 and 16 are hydraulic power sources, 18 is a switching valve, 21 is a drum rotating clutch, and 22 is a brake release cylinder.

Claims (1)

[Scope of Claims] 1. In a hydraulic crane winch device having a hydraulically operated winch drum rotation clutch and a negative brake mechanism of a spring-operated hydraulic release brake cylinder, a first hydraulic source that drives a winch drum rotation hydraulic motor; A second hydraulic power source in a separate system is provided, and a switch is provided between the two hydraulic power sources and the winch drum rotating clutch and the spring-actuated hydraulic pressure release brake cylinder to selectively supply pressure oil from both oil sources to them. A clutch/brake control circuit for a hydraulic crane winch characterized by an intervening valve. 2 The switching valve is connected to the pressure fluid from the first hydraulic source and the second hydraulic pressure source.
a valve position capable of directing pressurized fluid from a hydraulic source to a winch drum rotating clutch and a spring-actuated hydraulic release brake cylinder to control the hoisting and lowering states; Claim 1, characterized in that the switching valve is a switching valve having a valve position that can be controlled to a brake lock state for discharging fluid inside the switching valve.
Clutch/brake control circuit for the hydraulic crane winch described in Section 1. 3 The switching valve is connected to the pressure fluid from the first hydraulic source and the second hydraulic pressure source.
a valve position capable of directing pressurized fluid from a hydraulic source to a winch drum rotating clutch and a spring-actuated hydraulic release brake cylinder to control the hoisting and lowering states; A valve position that can control the brake to a locked state by discharging the fluid inside the brake, and a valve position that cuts off the pressure fluid of the first hydraulic pressure source and guides the pressure fluid of the second hydraulic pressure source to the spring-actuated hydraulic pressure release brake cylinder to release the brake. A clutch/brake control circuit for a hydraulic crane winch according to claim 1, characterized in that the switching valve has the following.