JP2000095480A - Rope delivery preventing device for hydraulic winch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rope delivery preventing device of a winch, capable of preventing excessive delivery of a rope after landing of a lifted load without detecting the landing. SOLUTION: A brake device (a second brake device 7) for preventing delivery of a rope is mounted on part of a winch drum 41 in addition to an existing brake (a first brake device 6). An electromagnetic proportional pressure reducing valve 91 whose pressure reducing degree is adjusted by a volume switch 92 between the second brake device 7 and a pressure source 12 is mounted. A braking force of the second brake device 7 is set at a value corresponded to the pressure reducing degree of the electromagnetic proportional pressure reducing valve 91. It is thus possible to apply braking force to prevent the drum 41 from rotating by its inertial force to a brake drum 41b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic winch rope unwinding prevention device for preventing an unwound rope of a hoisting winch mounted on a crawler crane or the like.

[0002]

2. Description of the Related Art The work performed by free-falling a hoisting winch mounted on a crawler crane includes a work by a dynamic compaction method and an excavation work using a bucket. The dynamic consolidation method is a method used to improve the ground over a relatively wide area, for example, when constructing an airport runway. Is dropped a predetermined number of times from a predetermined height, and the ground is improved by the fall energy. In such work, from the viewpoint of work efficiency,
It is required that the weight is dropped as many times as possible as soon as possible. For this purpose, it is necessary to apply a brake simultaneously with the landing of the weight that has fallen freely and to prevent the hoisting rope from being unnecessarily extended. Similarly, when performing an excavation work (for example, a clamshell work or a club bucket work) by digging into a bucket, it is necessary to apply a brake at the same time as the digging of the bucket and to prevent the hoisting rope from being pulled out excessively. It is said.

[0003] When the brake is applied early during the above-mentioned dynamic consolidation method or the operation using a bucket, a part of the falling energy of the weight or the bucket deforms the friction energy and the boom during braking. It is converted into energy, energy loss occurs, and the work efficiency deteriorates, and excessive tension acts on the hoisting rope, which may cause unstable vehicle conditions and damage to the hoisting rope. is there. Conversely, if the brake is applied at a late timing, the rope will be extended even after landing due to the inertia of the winch drum, and the winch drum will be in a turbulent state, so it is necessary to rewind the rope around the winch drum. Efficiency deteriorates. After landing,
Since no tension is exerted on the extra unreeled rope, the rope is out of control. In the bucket work, work is frequently performed under conditions where it is difficult to visually check the bucket, such as underground or on the sea floor. Therefore, it is particularly difficult to make the brake application timing appropriate. To solve such a problem concerning the timing at the time of the brake operation, Japanese Utility Model Application Laid-Open Publication No.
No. 173190 discloses a device in which a brake is automatically applied after the landing of a bucket during lowering.

In the apparatus described in this publication, a timer contact which is turned on when the lowering operation of the control valve elapses for a predetermined time or more, and which is turned on when the discharge fluid pressure of the hydraulic motor falls below a predetermined value due to the landing of the bucket. A pressure switch is provided, and when both the timer contact and the pressure switch are turned on, an open signal is output to the relief valve to release the pressure oil from the hydraulic pump. As a result, the supply of the pressure oil to the hydraulic motor is shut off, the rotation of the hydraulic motor is stopped, and the extra unreeling of the rope after landing is prevented.

[0005]

However, in the apparatus described in the above publication, the landing of the bucket is detected by the discharge fluid pressure of the hydraulic motor, and the hydraulic brake is operated by controlling the hydraulic oil in the circuit. So
Not only is the configuration complicated, but also it is difficult to quickly detect the landing of the bucket and quickly apply the brake, causing problems such as a delay in the motor stop operation. As a result, as described above, extra pulling out of the rope and the like occur, and the working efficiency deteriorates. Further, the one described in the above-mentioned publication is intended for a device under a power winding which is much slower than a falling speed in a free fall, and is not suitable for a dynamic consolidation method requiring a free falling or a falling speed close thereto.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic winch rope capable of reliably preventing an extra unreeling of a rope after hanging and landing without requiring a complicated structure such as detecting landing of a hanging load. An object of the present invention is to provide a feeding prevention device.

[0007]

Means for Solving the Problems (1) Referring to FIG. 1 showing one embodiment, the invention of claim 1 is a hydraulic pressure driven to be hoisted or lowered by a command from an operation lever 10. A motor 2; a hoisting drum 4 on which a driving torque from the hydraulic motor 2 is transmitted in a hoisting state or a hoisting state in a transmitting state; and a hoisting load free-falls in a non-transmitting state. The present invention is applied to a hydraulic winch rope unwinding prevention device including a first braking device 6 that applies a predetermined braking force F1 to the drum 4 to inhibit rotation of the hoisting drum 4. And the hoisting drum 4
The above-mentioned problem is achieved by providing the second braking device 7 that applies a braking force F2 smaller than the predetermined braking force F1 to the second. (2) The invention of claim 2 includes a braking force adjusting means 9 for adjusting the braking force F2 of the second braking device 7. (3) In the invention of claim 3, the second braking device 7 is a disk brake. (4) According to the invention of claim 4, as shown in FIG. 3, the braking force adjusting means 9 detects the hoisting of the suspended load.
When the lifting of the suspended load is detected, the operation of the second braking device 7 is invalidated.

[0008] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easier to understand. However, the present invention is not limited to this.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. -First Embodiment- FIG. 1 is a hydraulic circuit diagram showing a configuration of a hydraulic winch control device according to a first embodiment of the present invention. The first embodiment is different from a brake device (first brake device 6 as will be described later) used in a normal hoisting and unwinding operation, and is a brake device exclusively for preventing the winding rope from being fed out (as will be described later). A second brake device 7) is provided, and the details thereof will be described below.
As shown in FIG. 1, the winch control device according to the first embodiment includes a variable displacement hydraulic pump 1 and a variable displacement hydraulic motor 2 driven by pressure oil discharged from the hydraulic pump 1. A directional control valve 3 for controlling the flow of hydraulic oil supplied from the hydraulic pump 1 to the hydraulic motor 2, a hoisting winch 4 driven to hoist and lower by a driving torque from the hydraulic motor 2, A clutch device 5 for transmitting or not transmitting the driving torque to the hoisting winch 4
And a first brake device 6 for stopping the driving of the hoisting winch 4, a second brake device 7 for applying a predetermined braking force to the hoisting winch 4, and a clutch device 5 and a first brake device 6. A valve device 8 for controlling the operation, a control device 9 for controlling the operation of the second brake device 7, an operation lever 10 for inputting a hoisting and lowering command of the hoisting winch 4 by an operator, and operation by the operating lever 10 Pilot valves 11A and 11B and pilot valves 11A and 11B
And a pilot oil pressure source 12 for supplying pressure oil to each of the valve device 8 and the control device 9.

The hoisting winch 4 has a drum 41 around which a winch rope 42 is wound, and an output shaft 41 connected to the hydraulic motor 2 via the speed reducer 13 at the center of the drum 41.
a is inserted. The clutch device 5 is provided on the output shaft 41a.
Is connected, and the clutch device 5 rotates integrally with the output shaft 4a. The clutch device 5 has a clutch cylinder 5a,
When the pressure oil from the hydraulic pressure source 21 is supplied to the rod-side oil chamber of the clutch cylinder 5a, the cylinder 5a is retracted, the drum 41 is separated from the clutch device 5, and the clutch is released. Further, when the supply of the pressure oil from the hydraulic pressure source 12 is stopped, the cylinder 5a is extended by the urging force of the spring provided on the clutch cylinder 5a, and the drum 41 and the clutch device 5 come into contact with each other and the clutch is connected. Is done. One end of the drum 41 is provided with a brake drum 41b integral with the drum 41, and the other end is provided with a brake disk 41c integral with the drum 41. The braking force from the first brake device 6 acts on the brake drum 41b, and the second brake device 7 acts on the brake disc 41c.
The braking force from acts.

The first brake device 6 is an expanding / contracting band type brake having a brake cylinder 6a, and pressure oil from a hydraulic source 12 is supplied to the brake cylinder 6 via a valve device 8.
When the cylinder 6a is supplied to the rod-side oil chamber a, the cylinder 6a is retracted and the brake is released, and when the supply of pressure oil is stopped, the cylinder 6a is extended by the urging force of a spring provided in the brake cylinder 6a, The brake is activated. Since a band-type brake can generally obtain a large braking force, it is possible to hold a suspended load having a predetermined weight in the air when the first brake device 6 is in operation. Although not shown, the band type brake is also operated by a foot brake. The second brake device 7 will be described later.

The valve device 8 includes a hydraulic source 12 and a clutch device 5.
, An electromagnetic switching valve 81 disposed between the hydraulic pressure source 12 and the first
And hydraulic pilot switching valves 82 and 83 arranged in series between the brake devices 6. The solenoid 81a of the electromagnetic switching valve 81 is connected to a power supply 85 via a free fall switch 84 for instructing a free fall of the suspended load. When the free fall switch 84 is turned on, the solenoid 81a is excited to position the electromagnetic switching valve 81. (A)
From (b) to (b). The pilot port of the hydraulic pilot switching valve 82 is connected to the outlet port of the electromagnetic switching valve 81, and when the free fall switch 84 is turned on, the electromagnetic switching valve 81 is switched to the position (b).
The hydraulic pilot switching valve 82 is switched from the position (a) to the position (b) by the supply of the pilot pressure oil from the hydraulic source 12. The pilot port of the hydraulic pilot switching valve 83 is connected to the pilot valve 11 via the shuttle valve 14.
When the operating lever 10 is operated from the neutral position and the pilot pressure oil is supplied from the hydraulic pressure source 12, the hydraulic pilot switching valve 83 is switched from the position (a) to the position (b).

The second brake device 7 is a disk type brake having two sets of brake cylinders 7a. The primary pressure P1 from the hydraulic pressure source 12 is reduced to a predetermined secondary pressure P2 by the control device 9 as described later. Then, it is supplied to the head side oil chamber of the brake cylinder 7a. By the supply of the pressure oil, the cylinder 7a is extended against the urging force of the spring provided on the brake cylinder 7a, and a state where a predetermined braking force is applied is established. As is apparent from FIG. 1, the second brake device 7 operates independently of the operation lever 10 and the free fall switch 84.

The control device 9 controls the primary pressure P from the hydraulic pressure source 12.
Electromagnetic proportional pressure reducing valve 91 for reducing 1 to a predetermined secondary pressure P2
(Hereinafter simply referred to as a pressure reducing valve), a stepless switching type volume switch 92 for instructing the degree of pressure reduction of the pressure reducing valve 91, and control of the pressure reducing valve 91 so that the degree of pressure reduction corresponds to a command from the volume switch 92. Controller 9 that outputs signals
And 3. Operation amount α of volume switch 92
And the braking force F2 of the second brake device 7
For example, as shown in FIG. In FIG. 2, when the operation amount α is the minimum (0%), the degree of pressure reduction of the pressure reducing valve 91 is controlled so that the secondary pressure P2 = 0, and as a result, the braking force F2 = 0. In addition, the operation amount α is maximum (100%)
, The degree of pressure reduction of the pressure reducing valve 91 is controlled such that the secondary pressure P2 = P1. As a result, the braking force F2 = F2max
It is said. The volume switch 91 is arbitrarily operated by the operator, and the braking force F2 of the second brake device 7 is controlled to a value that immediately stops the rotation of the drum 41 due to the inertial force after the suspension landing.

FIG. 2 also shows a braking force F1 of the first brake device 6 for reference. In FIG. 2, the maximum braking force F2max of the second braking device 7 is set to a value (for example, about 1/3) smaller than the braking force F1 of the first braking device 6. At the time of a free fall, a large rotational force acts on the drum 41 before the landing of the suspended load due to the gravity of the suspended load and the inertial force of the drum 41. Therefore, when the suspended load is held in the air, a large braking force F1 is required like the first brake device 6. On the other hand, only the inertial force of the drum 41 acts on the drum 41 after the suspension landing, so that a small braking force F2 such as the second brake device 7 is sufficient to stop the drum 41 after the landing.

Next, the characteristic operation of the present embodiment will be described. (1) Hoisting / Unwinding Operation When the operating lever 10 is operated to the hoisting side or the lowering side to perform the hoisting / unwinding operation, the pilot valve 11A or 11B is driven in accordance with the operation amount, and the pressure from the hydraulic source 12 is increased. Oil is supplied to the pilot port of the control valve 3.
As a result, the control valve 3 is switched to the position (A) side or the position (B) side, and the pressure oil from the hydraulic pump 1 is supplied to the hydraulic motor 2 via the control valve 3 so that the hydraulic motor 2 is driven. You. Also, by operating the operation lever 10,
The hydraulic pilot switching valve 83 is switched to the position (b). Here, the free fall switch 84 is turned off, and the electromagnetic switching valve 81 is switched to the position (a) shown. Therefore, the pressure oil from the hydraulic pressure source 12 is supplied to the rod-side oil chamber of the brake cylinder 6a via the hydraulic pilot switching valves 83 and 82.
Is released, and the drum 41 is driven up or down. At this time, the degree of pressure reduction of the pressure reducing valve 91 is controlled in accordance with the operation amount of the volume switch 92, and the primary pressure P1 from the hydraulic pressure source 12 is reduced to the secondary pressure P2 corresponding to this pressure reducing degree, and the second brake The oil is supplied to the head-side oil chamber of the cylinder 7 a of the device 7. As a result, the second brake device 7 also operates during the hoisting and lowering work,
Since the braking force F2 of the second brake device 7 is small,
There is no major hindrance to the hoisting and unwinding operations. In this case, the operation of the second brake device 7 is released (F2 =
0) To set the volume switch 92 to zero (α = 0)
Should be set to. In order to stop the rotation of the drum 41, the operation lever 10 is returned to the neutral position to operate the first brake device 6, or the operator operates a positive brake (not shown) to operate the brake to operate the brake. It should be done.

(2) Free Fall Operation When the suspended load is free fall, first, the volume switch 93 is operated by a predetermined amount α to apply a predetermined braking force F2 from the second brake device 7 to the brake drum 41b. Let it. The predetermined braking force F2 in this case is the braking force F necessary to prevent rotation of the drum 41 due to inertial force.
2, which is determined in consideration of the hanging load amount, the drop height, the braking time, and the like. Next, when the free fall switch 84 is turned on, the solenoid 81a of the electromagnetic switching valve 81 is excited, the electromagnetic switching valve 81 is switched to the position (b), and the hydraulic oil from the hydraulic power source 12 is supplied to the clutch via the electromagnetic proportional valve 81. It is supplied to the rod-side oil chamber of the cylinder 5a, and the clutch is released. At the same time, the hydraulic pilot switching valve 8
2 is switched to the position (b), the pressure oil from the hydraulic pressure source 12 is supplied to the rod-side oil chamber of the brake cylinder 6a via the electromagnetic proportional valve 81 and the hydraulic pilot switching valve 82, and the brake is released and suspended. The load initiates a free fall. In this case, since the braking force F2 is constantly acting on the brake drum 41b via the brake disk 41c, the rotation of the drum 41 is immediately stopped after landing by the braking force F2, and as a result, the operator is consciously conscious. The extension of the rope 42 is prevented without operating the brake by the foot brake pedal. When the set braking force F2 is insufficient or excessive, the brake switch F2 may be adjusted by appropriately operating the volume switch 92.

As described above, according to the first embodiment, the second brake device 7 is newly provided only for preventing the lifting of the hoisting rope 42, and is always operated at the time of a free fall. This eliminates the need for the operator to operate the brake at the same time as landing, thereby improving workability. Further, since it is not necessary to detect the landing of the suspended load, a delay in the braking operation due to an error in the landing detection and the like is prevented,
The drum 41 can be stopped at an appropriate timing. Further, since the second brake device 7 is provided independently of the existing brake device, that is, the first brake device 6, the configuration becomes easier as compared with a case where the existing brake device is modified. Further, the present invention can be easily applied to a crane or the like equipped with an existing brake device. In this case, even if the second brake device breaks down, the existing brake device can be used as usual, so that there is no disadvantage to the conventional brake operation. Furthermore, the second brake device 7 is connected to the drum 41
Since it is sufficient to use a weak braking force corresponding to the inertia force of the vehicle, the size of the apparatus can be reduced, and the loss due to the operation of the brake before the landing of the suspended load can be minimized. In addition, since the second brake device is a disc brake having excellent heat dissipation, fine adjustment of the braking force is facilitated as compared with a band brake capable of high output.

-Second Embodiment- FIG. 3 is a hydraulic circuit diagram showing a configuration of a rope unwinding prevention device according to a second embodiment of the present invention. In FIG. 3, the same portions as those in FIG.
Hereinafter, the differences will be mainly described. As shown in FIG. 3, in the second embodiment, a hoisting detector 15 such as a pressure switch for detecting whether or not a hoisting operation of the operation lever 10 is provided between the pilot valve 11B and the shuttle valve 14. , A signal from the hoisting detector 15 is supplied to a changeover switch 9 provided in a circuit for communicating the controller 93 and the pressure reducing valve 91.
4 is input. When the signal from the hoisting detector 15 is off, the changeover switch 94 is turned on (closed), and
As a result, as in the first embodiment, the degree of pressure reduction of the pressure reducing valve 91 is controlled according to the operation amount α of the volume switch 92. When the signal from the hoist detector 15 is on, the changeover switch 94 is turned off (opened). As a result, the signal from the volume switch 92 becomes invalid, and the pressure reduction degree of the pressure reducing valve 91 is always maximum. , That is, the secondary pressure P2
= 0. Thereby, the second brake device 7 is released during the hoisting operation.

As described above, according to the second embodiment, the second brake device 7 is released at the time of hoisting work. Therefore, in addition to the effects described in the first embodiment, when the hoisting operation is further performed. This prevents the brake from being dragged, thereby enabling more efficient work.

In the above embodiment, the electromagnetic proportional pressure reducing valve 91 operated by an electric signal from the controller 93 is used, but a manual variable pressure reducing valve may be used. Further, although the stepless changeover type volume switch 92 is used, a changeover switch that can be switched to a plurality of steps according to the weight of the suspended load or the like may be used. Furthermore, a mode switch that is operated according to a work mode such as a bucket work or a crane work may be provided to invalidate the operation of the second brake device 7 in a normal crane work that does not require free fall work. Good. Furthermore, the mobile crane is equipped with an overload prevention device called a moment limiter. The weight of the suspended load is calculated by a signal from the moment limiter, and the pressure reduction degree of the pressure reducing valve 91 is controlled using the value. You may make it. When a moment limiter is not mounted like an excavator,
The weight of the suspended load may be calculated from the rope tension or the like. In the above embodiment, the control device 9 adjusts the braking force F2 of the second brake device 7;
The braking force F2 may be adjusted by changing the type of spring provided in the cylinder 7a of the second brake device 7, or by changing the diameter of the cylinder 7a.

Further, although the second brake device 7 is a disk brake, other brakes may be used. For example, a hydraulic pump as a resistor is connected to the output shaft 41a of the drum 41, and a variable braking force is applied to the output shaft 41a by changing the relief pressure of the pressure oil discharged from the hydraulic pump. You may. Furthermore, a pedal having a lock mechanism and a booster valve (so-called positive brake) driven by pedal operation may be provided instead of the control device 9, and the disc brake 7 may be operated by pedal operation.

[0023]

As described above in detail, according to the present invention, the following effects can be obtained. (1) According to the first aspect of the present invention, a second braking device for applying a smaller braking force is provided separately from the first braking device for stopping the driving of the hoist drum. Can be braked only by detecting the inertial force of the drum without detecting the landing of the rope, and it is possible to prevent the rope from being unnecessarily extended after hanging and landing. (2) According to the second aspect of the invention, since the braking force of the second braking device can be adjusted, it is possible to adjust the braking force while observing the work situation while feeling that the braking force is excessive or insufficient. Even if there is, it can be easily changed to the optimal braking force. (3) According to the third aspect of the invention, since the second brake device is a disc brake, fine adjustment of the braking force is possible. (4) According to the fourth aspect of the present invention, the operation of the second brake device is invalidated during the hoisting operation of the suspended load, so that the brake is not dragged during hoisting and the work efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a configuration of a rope winch prevention device of a hoisting winch according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a correspondence relationship between an operation amount of a volume switch according to the embodiment and a braking force of a second brake device controlled by the operation amount.

FIG. 3 is a hydraulic circuit diagram showing a configuration of an apparatus for preventing a rope from being pulled out of a hoisting winch according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 2 hydraulic motor 4 hoisting winch 6 first brake device 7 second brake device 9 control device 10 operating lever 15 hoisting detector 91 electromagnetic proportional pressure reducing valve 92 volume switch 93 controller 94 changeover switch

 ──────────────────────────────────────────────────の Continuing from the front page (72) Koji Funato, Inventor 650, Kandamachi, Tsuchiura-shi, Ibaraki Prefecture Within the Tsuchiura Plant of Hitachi Construction Machinery Co., Ltd. (72) Masami Ochiai 650, Kandamachi, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery (72) Inventor Teruo Igarashi 650, Kandamachi, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. (72) Inventor Akira Nakayama 650, Kandamachi, Tsuchiura-shi, Ibaraki Hitachi, Ltd. Inside the Tsuchiura Plant (72) Inventor Tsutomu Udagawa 650, Kandachi-cho, Tsuchiura-shi, Ibaraki F-term in the Tsuchiura Plant of Hitachi Construction Machinery Co., Ltd. (reference) 3F204 AA04 CA05 FA02 FB04 FC08 FD02 3F205 AA07

Claims (4)

[Claims] 1. A hydraulic motor driven to hoist or lower by a command from an operation lever, and a hoisting or lowering drive is performed in a transmission state of a driving torque from the hydraulic motor, and a suspended load is free in a non-transmission state. A rope of a hydraulic winch, comprising: a hoisting drum to be fallen; and a first braking device for applying a predetermined braking force to the hoisting drum at least when the operation lever is in a neutral state to inhibit rotation of the hoisting drum. The unwinding prevention device, further comprising a second braking device that applies a braking force smaller than the predetermined braking force to the hoist drum, wherein the hydraulic winch rope unwinding prevention device is provided. 2. The hydraulic winch rope unwinding prevention device according to claim 1, further comprising a braking force adjusting means for adjusting a braking force of the second braking device. apparatus. 3. The rope winch prevention device for a hydraulic winch according to claim 1, wherein the second brake device is a disc brake. 4. The apparatus according to claim 2, wherein the braking force adjusting means has a hoist detector for detecting hoisting of the suspended load, and the hoisting of the suspended load. Is detected, the second
A hydraulic winch rope unwinding prevention device, wherein the operation of the braking device is invalidated.