JPH11171474A - Hook suspension length holding device for crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold up a hook suspension length almost constant by interlocking those of boom expansion operations with both lowering and winding operations together at a time when a boom's expansion operation is carried out. SOLUTION: In a crane equipped with a boom performing expansion operations by a boom expansion hydraulic cylinder and a winch performing both winding and lowering operations of a hook by a winch hydraulic motor 10, a contraction side oil camber 26 of the boom expansion hydraulic cylinder and a lowering duct line 28 of the winch hydraulic motor 10 are interconnected to each other in the point midway in a contraction duct line 27 connecting the contract side oil chamber 26 of the boom expansion hydraulic cylinder and a contraction side port B of a boom expansion selector valve 17 together, and in this constitution, it is also provided with an interlocking selector valve 30 interconnecting a winding duct line 29 of the winch hydraulic motor 10 and the contraction side port B of the boom expansion selector valve 17 to each other and two interlocking duct lines 31 and 32, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane hook suspension length holding device for maintaining a hook suspension length substantially constant when a crane boom is extended and contracted.

[0002]

2. Description of the Related Art In a crane having a telescopic boom,
A winch is provided on the column that supports the base end of the boom, and the wire rope that is fed out of the winch and guided is guided to the boom distal end, and is hooked on the hook via a pulley at the boom distal end. Hanging from the boom tip.

Accordingly, the hook hanging length (the distance between the lower end of the boom tip and the upper end of the hook) of the hook suspended from the boom tip changes as the boom expands and contracts. That is,
Extending the boom reduces the hook suspension length, and reducing the boom increases the hook suspension length.

The hydraulic circuit of a conventional crane is, for example, shown in FIG.
It is configured as shown in FIG. Here, the hydraulic cylinder 9 for raising / lowering the boom is the switching valve 15 for raising / lowering the boom, the hydraulic motor 10 for the winch is the switching valve 16 for the winch, the hydraulic cylinder 8 for extending / retracting the boom is the switching valve 17 for extending / retracting the boom, and the hydraulic motor 5 for turning is rotating. The switching valve 18 and the outrigger hydraulic cylinders 3L and 3R are connected to the discharge pipeline 22 of the hydraulic pump 21 and the return pipeline 24 to the tank 23 via the outrigger switching valves 19L and 19R.

[0005] These switching valves 15, 16, 17, 18,
Reference numerals 19L and 19R denote three-position manual operation switching valves, which are manually operated by an operator to be operated by a hydraulic cylinder 9 for raising / lowering a boom, a hydraulic motor 10 for a winch, a hydraulic cylinder 8 for extending / retracting a boom, and a hydraulic motor 5 for turning. And the left and right outrigger hydraulic cylinders 3L, 3R can be operated. In the neutral position, the discharge line 22 is communicated with the return line 24.

[0006] Between the discharge line 22 and the return line 24,
A relief valve 25 is provided. During crane operation, it is necessary to extend and retract the boom.In this case, in order to maintain a constant hook suspension length, the crane operator performs the winch lowering operation at the same time as the boom extension operation and the boom lowering operation. It is necessary to perform a winch hoisting operation simultaneously with the reducing operation. Such simultaneous operation of the boom expansion / contraction switching valve 17 and the winch switching valve 16 is troublesome for the operator, and it is extremely difficult to perform properly and requires skill.

Therefore, in order to facilitate the operation, a crane using a winch having a hydraulic tuning motor rotatably driven by the expansion and contraction of the telescopic cylinder and a hydraulic main motor rotatably driven independently of the telescopic cylinder. Has been proposed (see Japanese Patent Publication No. 61-19555).

[0008] In this retractable telescopic tuning device for a crane, the interlocking operation of the telescopic operation of the boom and the lowering and raising operation of the winch is performed by:
It is configured so that the operation is performed by a tuning circuit in which the telescopic cylinder and the hydraulic pressure tuning motor are connected in series, and that the independent operation under the winch is performed by an independent hydraulic circuit for the hydraulic main motor.

For this reason, the boom extending and retracting operation and the operation on the lower and upper windings of the winch can be synchronized and synchronized just by performing the boom extending and retracting operation. Further, while the telescopic cylinder and the hydraulic pressure tuning motor are linked, the hydraulic main motor can be further rotated forward and backward.

[0010]

However, such a retractable telescopic tuning device for a crane requires a hydraulic tuning motor and a hydraulic main motor for a winch, and each of the motors is driven to rotate. Since the hydraulic circuit and the hydraulic pump described above are also required, there is a problem that the configuration of the apparatus is complicated and the cost is increased.

The present invention solves such a problem in a crane provided with a telescopic boom. When the telescopic operation of the boom is performed, the telescopic operation of the boom and the operation of lowering and winding the winch are linked. An object of the present invention is to provide a crane hook suspension length holding device which can maintain a hook suspension length substantially constant, can eliminate the troublesome operation of an operator, and is inexpensive.

[0012]

According to the hook hanging length holding device for a crane of the present invention, a boom which extends and retracts by a hydraulic cylinder for extending and retracting a boom, and a winch which performs a hoisting and lowering operation of a hook by a hydraulic motor for a winch. A crane equipped with a boom extendable hydraulic cylinder and a boom extendable hydraulic cylinder. By providing an interlocking changeover valve and an interlocking line that communicates with the lowering line of the hydraulic motor for the winch and the reduction side port of the boom expansion / contraction changeover valve of the hydraulic motor for the winch. The problem has been solved.

In the hook hanging length holding device of the crane of the present invention, when the boom is extended or contracted while the hook hanging length is kept constant during the crane operation, the interlocking switching valve is switched to the interlocking side. Then, the reduction side oil chamber of the hydraulic cylinder for boom extension and contraction and the lowering line of the hydraulic motor for winch communicate with each other, and the raising line of the hydraulic motor for winch and the reduction side port of the switching valve for boom expansion and contraction communicate with each other. Therefore, when the operator operates the boom expansion / contraction switching valve, the boom expansion / contraction hydraulic cylinder and the winch hydraulic motor are interlocked.

That is, when the operator switches the boom extension / retraction switching valve to the extension side to extend the boom extension / retraction hydraulic cylinder, the oil in the reduction side oil chamber of the boom extension / retraction hydraulic cylinder is supplied to the winch via the interlocking switching valve. The hydraulic motor for the winch enters the lowering line of the hydraulic motor to perform the lowering operation of the hydraulic motor for the winch. The return oil from the winch hydraulic motor returns to the tank from the hoisting line of the winch hydraulic motor, via the interlocking switching valve, and the reduction side port of the boom expansion / contraction switching valve.

When the operator switches the boom expansion / contraction switching valve to the reduction side, the hydraulic oil from the hydraulic pump enters the hoist hydraulic motor winding line via the interlocking switching valve.
The winding operation of the winch hydraulic motor is performed. The return oil from the winch hydraulic motor enters the reduction-side oil chamber of the boom expansion / contraction hydraulic cylinder through the lowering line of the winch hydraulic motor via the interlocking switching valve, and reduces the boom expansion / contraction hydraulic cylinder.

Accordingly, when the boom is extended, the winch wire rope is paid out in synchronization with the extension of the boom, and the hook suspension length is kept substantially constant. When the boom is reduced, the winch wire rope is synchronized with the same. And the hook suspension length is maintained substantially constant.

If a distribution / collection valve is provided in the middle of the interlocking pipeline, the unit volume of the reduction-side oil chamber of the boom extending / retracting hydraulic cylinder (pressure receiving area of the reduction-side oil chamber × unit stroke) and the hydraulic motor for the winch Even if the relationship with the required amount of oil per rotation is not appropriate, the extension / retraction operation of the hydraulic cylinder for extending / retracting the boom and the lower / upward operation of the hydraulic motor for the winch can be properly synchronized.

[0018]

FIG. 1 is a front view of a crane provided with a hook hanging length holding device according to an embodiment of the present invention. FIG. 2 is a hydraulic circuit diagram of the hook hanging length holding device of the crane. It is.

As shown in FIG. 1, the crane 1 has a column 6 pivoted by a pivoting hydraulic motor 5 on a base 4 supported by an outrigger 2 having left and right hydraulic cylinders 3L, 3R for outriggers. A base end of a boom 7 is pivotally connected to an upper end of the column 6. The boom 7 is extended and retracted by a hydraulic cylinder 8 for extending and retracting the boom, and is raised and lowered by a hydraulic cylinder 9 for raising and lowering the boom.

The column 6 is provided with a winch 11 which is operated by a winch hydraulic motor 10 for hoisting and lowering. The wire rope 12 which is fed from the winch and fed is guided to the tip of the boom 7. The hook 13 is suspended from the tip of the boom 7 by being hooked on the hook 13 via a pulley (not shown) at the tip of the boom 7.
Therefore, normally, the hook suspension length (the distance between the lower end of the boom tip and the upper end of the hook) L changes as the boom 7 expands and contracts.

That is, when the boom 7 is extended, the hook suspension length L becomes shorter, and when the boom 7 is reduced, the hook suspension length L becomes longer. In this crane 1, as shown in FIG. 2, the hydraulic cylinder 9 for raising and lowering a boom is a switching valve 15 for raising and lowering a boom, the hydraulic motor 10 for a winch is a switching valve 16 for a winch, and the hydraulic cylinder 8 for extending and retracting a boom is a switching valve for extending and retracting a boom. 17, the turning hydraulic motor 5 is used for the turning switching valve 18, and the outrigger hydraulic cylinders 3L, 3R are connected to the discharge pipe 2 of the hydraulic pump 21 via the outrigger switching valves 19L, 19R.
2 and a return line 24 to the tank 23.

These switching valves 15, 16, 17, 18,
Reference numerals 19L and 19R denote three-position manual operation switching valves, which are manually operated by an operator to be operated by a hydraulic cylinder 9 for raising / lowering a boom, a hydraulic motor 10 for a winch, a hydraulic cylinder 8 for extending / retracting a boom, and a hydraulic motor 5 for turning. And the left and right outrigger hydraulic cylinders 3L, 3R can be operated. In the neutral position, the discharge line 22 is communicated with the return line 24. Between the discharge line 22 and the return line 24,
A relief valve 25 is provided.

Here, in the middle of the reduction pipe 27 connecting the reduction side oil chamber 26 of the boom expansion and contraction hydraulic cylinder 8 and the reduction side port B of the boom expansion and contraction switching valve 17, the boom expansion and contraction hydraulic cylinder 8 is connected. Interlocking communication in which the reduction side oil chamber 26 communicates with the winding down line 28 of the winch hydraulic motor 10 and the winding line 29 of the winch hydraulic motor 10 communicates with the reduction side port B of the boom expansion / contraction switching valve 17. Switching valve 30 and interlocking conduits 31 and 32 are provided. Here, a two-position electromagnetic switching valve is used as the interlocking switching valve 30, but a manually operated switching valve may be used. The extension side oil chamber 33 of the boom extension / retraction hydraulic cylinder 8 and the extension side port A of the boom extension / reduction switching valve 17 are connected by an extension conduit 34.

When the boom 7 is expanded and contracted while maintaining the hook suspension length L constant during the crane operation, the interlocking switching valve 30 is first switched to the interlocking side. Then, the reduction side oil chamber 26 of the boom extension / retraction hydraulic cylinder 8 and the lowering line 28 of the winch hydraulic motor 10 communicate with each other, and the lifting line 29 of the winch hydraulic motor 10 and the boom extension / reduction switching valve 17 are connected.
When the operator operates the boom expansion / contraction switching valve 17, the boom expansion / contraction hydraulic cylinder 8 and the winch hydraulic motor 10 are interlocked.

That is, the operator operates the boom extension / reduction switching valve 1
7 is switched to the extension side, the discharge line 2 of the hydraulic pump 21
The hydraulic oil supplied from 2 enters the extension-side oil chamber 33 of the boom extension / retraction hydraulic cylinder 8 from the extension conduit 34 to extend the boom extension / retraction hydraulic cylinder 8. Then, the oil in the reduction side oil chamber 26 of the hydraulic cylinder 8 for extending and retracting the boom is transferred to the interlocking switching valve 3.
0, through the interlocking conduit 31, enter the unwinding conduit 28 of the winch hydraulic motor 10, and perform the lowering operation of the winch hydraulic motor 10. The return oil from the winch hydraulic motor 10 is returned from the hoisting line 29 of the winch hydraulic motor 10 to the interlocking line 32, the interlocking switching valve 30, and the return line B from the reduction side port B of the boom expansion / contraction switching valve 17. Tank 2 after 24
Return to 3.

When the operator operates the boom extension / reduction switching valve 1
7 is switched to the reduction side, the pressure oil from the hydraulic pump 21 enters the hoisting line 29 of the winch hydraulic motor 10 via the interlocking switching valve 30 and the interlocking line 32, and the winding of the winch hydraulic motor 10 Perform the above operation. The return oil from the winch hydraulic motor 10 enters the reduction side oil chamber 26 of the boom extendable hydraulic cylinder 8 from the lowering line 28 of the winch hydraulic motor 10 via the interlocking line 31 and the interlocking switching valve 30. ,
The hydraulic cylinder 8 for boom extension and contraction is reduced. The oil in the extension-side oil chamber 33 of the hydraulic cylinder 8 for extending and retracting the boom is supplied to the extension pipe 3
4. Return to the tank 23 via the return line 24 from the extension side port A of the boom expansion / contraction switching valve 17.

Therefore, when the boom 7 is extended, the wire rope 12 of the winch 11 is paid out in synchronization with the extension of the boom 7, and
When the hook suspension length L is kept substantially constant, and when the boom 7 is reduced, the wire rope 12 of the winch 11 is retracted in synchronism therewith, and the hook suspension length L is kept substantially constant.

When the winch switching valve 16 is operated to the lower side while the interlocking switching valve 30 is switched to the interlocking side, the lowering line 28 of the winch hydraulic motor 10 is connected via the interlocking switching valve 30. The boom extending and contracting hydraulic cylinder 8 communicates with the reduction side oil chamber 26, but if the boom extending and contracting switching valve 17 is in the neutral position, the extension pipe line 34 of the boom extending and retracting hydraulic cylinder 8 is connected to the boom extending and contracting switching valve. Since the boom extension / retraction hydraulic cylinder 8 is blocked at the extension side port A of 17, only the lowering operation of the winch hydraulic motor 10 is performed without performing the contraction operation. The return oil from the winch hydraulic motor 10 returns from the hoisting pipe line 29 to the tank 23 via the winch switching valve 16.

When the winch switching valve 16 is operated to the upper winding side while the interlocking switching valve 30 is switched to the interlocking side, the hoisting line 29 of the winch hydraulic motor 10 is connected via the interlocking switching valve 30. It communicates with the boom extension / reduction switching valve 17, but if the boom extension / reduction switching valve 17 is at the neutral position, only the hoisting operation of the winch hydraulic motor 10 is performed because the reduction side port B is blocked. The return oil from the winch hydraulic motor 10 returns to the tank 23 from the lower winding line 28 via the winch switching valve 16.

The expansion and contraction operation of the boom 7 and the winch 11
It is not possible to independently operate the hoisting and lowering operation of the winch 11 while synchronizing with the hoisting and lowering operation of, but such a function is not necessary in actual crane operation, so there is no problem in the operation.

When the interlocking switching valve 30 is not switched to the interlocking side, the hydraulic cylinder 8 for extending and retracting the boom and the hydraulic motor 10 for the winch operate independently as in the conventional one. Here, when the boom 7 is extended and contracted while the hook hanging length L is kept constant, the interlocking switching valve 30 is switched to the interlocking side in advance. If the configuration is such that the interlocking switching valve 30 is switched to the interlocking side at the same time as the operation so as to be electrically or mechanically interlocked, the operation becomes easier.

In order to keep the hook hanging length L constant when the boom 7 is extended and retracted, the unit volume of the reduced oil chamber 26 of the boom retract hydraulic cylinder 8 (the pressure receiving area of the reduced oil chamber × The unit stroke) Q and the required oil amount q per rotation of the winch hydraulic motor 10 need to be set in a predetermined relationship, for example, Q = kq (k is a constant).

When a new crane 1 is designed, the hydraulic cylinder 8 for extending and retracting the boom and the hydraulic motor 10 for the winch may be appropriately selected so as to satisfy this relationship. However, when the hook hanging length holding device of the present invention is used for the existing crane 1, the hydraulic cylinder 8 for extending and retracting the boom and the hydraulic motor 10 for the winch often do not satisfy the above relationship. Therefore, the existing crane 1
However, even if the interlocking switching valve 30 and the interlocking conduits 31 and 32 are simply added, the hook suspension length L may not be kept constant when the boom 7 is expanded and contracted.

For example, when Q> kq, when the boom 7 is expanded and contracted, the hook suspension length L changes as shown in FIG. In such a case, as shown in FIG. 4, a distribution / collection valve 40 is provided in the middle of the interlocking pipeline 31, and the interlocking switching valve 30 is moved from the reduction side oil chamber 26 when the boom extending / retracting hydraulic cylinder 8 is extended. A part of the oil entering the lowering line 28 of the winch hydraulic motor 10 is divided to the interlocking line 32 side through the interlock, and the lowering line of the winch hydraulic motor 10 is A part of the oil on the side of the interlocking pipe line 32 is made to flow to the return oil from 28. Thereby, when the boom 7 is extended and contracted, the hook suspension length L can be kept constant.

The hook hanging length holding device of this crane does not require a plurality of hydraulic motors or hydraulic pumps, and is provided in the hydraulic circuit of the conventional crane with the interlocking switching valve 30 and the interlocking pipelines 31, 32, or the like. Since it is only necessary to add the distribution / collection valve 40, the structure is simple and the cost is extremely low.

[0036]

As described above, according to the crane hook hanging length holding device of the present invention, when the boom is extended and retracted, the operation of extending and retracting the boom and the operation of lowering and lowering the winch are linked. As a result, the hook suspension length can be kept substantially constant, and the trouble of the operator's operation can be eliminated. Further, the structure is simple and the cost is low.

If a distribution / collection valve is provided in the middle of the interlocking pipeline, the relationship between the unit volume of the reduction side oil chamber of the hydraulic cylinder for extending and retracting the boom and the required amount of oil per rotation of the hydraulic motor for the winch is obtained. Even if it is not appropriate, the extension / retraction operation of the boom extension / retraction hydraulic cylinder and the winding / lowering operation of the winch hydraulic motor can be properly synchronized.

[Brief description of the drawings]

FIG. 1 is a front view of a crane provided with a hook hanging length holding device according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a hook hanging length holding device of the crane.

FIG. 3 is an explanatory diagram of a state at the time of boom extension and contraction.

FIG. 4 is a hydraulic circuit diagram of a hook hanging length holding device of a crane showing an example in which a distribution / collection valve is provided in the middle of an interlocking pipeline.

FIG. 5 is a hydraulic circuit diagram of a conventional crane.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crane 2 Outrigger 3 Boom extension / retraction cylinder 4 Base 6 Column 7 Boom 8 Boom extension / retraction hydraulic cylinder 10 Winch hydraulic motor 11 Winch 12 Wire rope 13 Hook 16 Winch switching valve 17 Boom extension switching valve 21 Hydraulic pump 22 Discharge pipe Path 23 Tank 24 Return line 26 Reduction side oil chamber 27 Reduction line 28 Lower line 29 Lifting line 30 Interlocking switching valve 31 Interlocking line 32 Interlocking line 33 Extension side oil chamber 34 Extension line 40 Distribution / collection valve

Claims (2)

[Claims] 1. A crane having a boom that extends and retracts by a hydraulic cylinder for extending and retracting a boom, and a winch that performs a lifting operation and a lowering operation of a hook by a hydraulic motor for a winch. In the middle of a reduction pipeline connecting the reduction side port of the boom expansion / contraction switching valve,
For interlocking, the communication between the reduction-side oil chamber of the hydraulic cylinder for boom expansion and contraction and the lowering line of the hydraulic motor for winch, and the connection between the lifting line of the hydraulic motor for winch and the reduction-side port of the switching valve for boom expansion and contraction. A hook hanging length holding device for a crane, wherein a switching valve and an interlocking conduit are provided. 2. The crane hook suspension length holding device according to claim 1, wherein a distribution collecting valve is provided in the middle of the interlocking pipeline.