WO1996009979A1

WO1996009979A1 - Method and apparatus for preventing over-winding of a winch of a mobile crane

Info

Publication number: WO1996009979A1
Application number: PCT/JP1995/001929
Authority: WO
Inventors: Shinya Koshii
Original assignee: Komatsu Ltd.
Priority date: 1994-09-26
Filing date: 1995-09-25
Publication date: 1996-04-04
Also published as: KR0182823B1; JP3276130B2; JPH0891772A

Abstract

The present invention relates to a method and an apparatus for preventing over-winding of a winch of a mobile crane wherein uncontrolled winding of a wire rope can be prevented when a hook is fixed. To this end, the method comprises the steps of reducing the pressure and volume of operating oil to a winch when a distance between a hook (6) and a member (4) becomes equal to or less than a predetermined value (L) in winding up the hook (6), and further winding it up in the reduced condition to thereby allow the hook and the member to be brought into abutment. In addition, the apparatus comprises a winding position detecting sensor (10) for detecting the location of the hook (6), a control device (20) for generating a control signal on receiving a signal from the sensor (10), flow rate control means (31) and pressure control means (35) for, respectively, reducing the discharging volume and pressure of a hydraulic pump (30).

Description

SPECIFICATION METHOD AND APPARATUS FOR PREVENTING WINCH OVERCOVER OF MOBILE CRANE

The present invention relates to a winch overwinding method for a mobile crane and an apparatus therefor, and more particularly to a winch overwinding prevention method for a mobile crane when winding up a wire rope and an apparatus therefor. Background technology

As shown in Fig. 5, a conventional mobile crane has a sheave bracket 4 with sheaves 2 and 3 attached to the end of a boom 1, and a hook 6 for hanging loads with a wire rope 5. Are hanging on. The wire rope 5 is driven by a hydraulically driven ゥ inch (not shown). When the mobile crane runs, wind up the wire rope 5 to prevent the hook 6 from wobbling, and fix it by bringing the upper surface 7 of the hook 6 into contact with the lower surface 8 of the sheave bracket 4 as shown in Fig. 6. And put them in a stowed state.

According to this conventional technique, when the wire rope 5 is wound up by the hydraulically driven winch and the hook 6 is brought into contact with the sheave bracket 4 to be in the retracted state, immediately after the hook 6 comes into contact with the sheave bracket 4, the winch is Stopping entanglement. However, the winding of the winch proceeds after the contact for a short time, so that a large tension is applied to the wire port 5. As a result, a so-called overwind phenomenon occurs, and the wound wire rope gets caught in the wire rope already wound on the winch drum, causing irregular winding. Moreover, it is extremely difficult for the operator to operate the winch so that this overwind phenomenon does not occur.

As a measure to solve the above problem, a sheave bracket is attached to the contact surfaces 7, 8 between the sheave bracket 4 and the hook 6 by using a rubber cushion (not shown). The force that prevented excessive force from being applied to the wire rope 5 when the hook 4 and the hook 6 came into contact with each other. The reduction of shock by this measure was not enough. Disclosure of the invention

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the related art, and it is intended to prevent a winch of a movable crane from being excessively wound when a hook is wound up and fixed. It is an object to provide a method and an apparatus thereof.

In the winch overwinding method for a movable crane according to the present invention, the hook for hanging load is wound up by a hydraulically driven winch, and the hook is brought into contact with a member at the end of the boom so as to abut the hook. In the method of winding the movable crane winch,

When hoisting the hook, when the distance between the hook and the member approached by the hoisting is less than a predetermined value, the hydraulic pressure and hydraulic oil amount to the hydraulic drive winch are reduced, and in this reduced state, It is characterized by winding up, hooking the hook and the member, and fixing them.

With this configuration, when the hook and the member come into contact with each other, the hydraulic pressure applied to the hydraulic drive winch and the oil tatami mat are reduced, so that the hoisting speed is low and the tension generated on the wire rope can be reduced. Thus, there is no danger that the wire rope to be wound will bite into the wire rope already wound on the winch and cause random winding. A winch overwind prevention device for a mobile crane according to the present invention includes a hydraulic pump, a hydraulic drive winch driven by the hydraulic pump, and a hanging load hook wound up by the hydraulic drive winch. At the crane winch hoist,

A take-up position detection sensor that detects the hook position, a control device that receives a signal from the take-up position detection sensor and transmits a control signal, and a flow rate that receives the control signal and reduces the discharge amount of the hydraulic pump It is characterized by comprising control means, and pressure control means for reducing the discharge pressure of the hydraulic pump in response to a control signal.

With this configuration, the winding position detection sensor detects the distance between the hook and the member, The control device that has received this detection signal transmits a control signal to the flow i control means and the pressure control means to reduce the flow rate and the pressure. As a result, occurrence of turbulent winding is prevented in the same manner as in the invention of the above method. BRIEF DESCRIPTION OF THE FIGURES

1A and 1B are views of the tip of a boom provided with a winding position detection sensor according to an embodiment of the present invention, and FIG. 1A shows a case where a distance between a hook and a sheave bracket is equal to or greater than a predetermined value L. FIG. 1B is a side view at a predetermined value L or less,

FIG. 2 is an explanatory diagram of a panel of a control device for crane work according to the embodiment,

FIG. 3 is a hydraulic circuit diagram of a winch control system according to the embodiment,

FIG. 4 is a flow chart when the hook is stored according to the embodiment.

Fig. 5 is a side view of the boom tip according to the prior art,

FIG. 6 is a side view showing a hook fixing state according to a conventional technique. BEST MODE FOR CARRYING OUT THE INVENTION

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method and an apparatus for preventing winch overwinding of a mobile crane according to the present invention will be described below in detail with reference to the accompanying drawings.

In FIG. 1, a sheave bracket (member at the end of the boom) 4 that holds sheaves 2 and 3 is fixed to the end of the boom 1, and a hook 6 is suspended by a wire rope 5 wound around the sheaves 2 and 3. Have been. A winding position detection sensor 10 is axially mounted on a side surface of the sheave bracket 4 by a pin 11. A rod 14 is suspended via a wire 13 from a rod 12 provided at the tip of the winding position detection sensor 10 so as to protrude. The winding position detecting sensor 10 detects that the wire 6 is in a state where the downward force due to the wire 14 is applied to the rod 12, that is, the distance between the hook 6 and the sheave bracket 4 becomes a predetermined value L or more. If tension is generated at 13, the switch is ON. 15 is ground.

If the vehicle is traveling, the upper surface of the hook 6 and the lower surface of the sheave bracket 4 8 Abuts and secures it to the stored state. When the storage state is set, a hydraulic drive winch (not shown) (not shown) is driven, and the hook 6 is wound up by the wire rope 5. During this winding, as shown in FIG. 1B, when the distance between the lower surface 8 of the sheave bracket 4 and the upper surface 7 of the hook 6 becomes shorter than a predetermined value L, the upper surface 7 of the hook 6 becomes a weight 14. Abut. After the contact, the wire 6 is lifted by the hoisting, and the wire 13 on which the unit 14 is suspended becomes loose. Due to this slack, the downward force applied to the rod 12 is eliminated, and the mouth 12 is moved upward by the force of a spring (not shown). Switch 0FF is set. The operation after the switch 0 FF will be described when explaining the flow of FIG.

In FIG. 2, the overwind alarm LED 21 is lit when the winding position detection sensor 10 becomes 0 FF. When the overwind alarm release switch 22 is turned ON, the overwind alarm release LED 23 is lit, but the overwind alarm LED 21 is turned off. The control device 20 also has a function as a moment limiter.

In FIG. 3, reference numeral 30 denotes a swash plate type variable displacement S-type hydraulic pump (hereinafter referred to as main pump 30), 31 denotes a swash plate control cylinder (flow control means), and a load sensing valve 3 2 ( Hereinafter, the LS valve 32 will control the swash plate control cylinder 31 that determines the discharge amount of the main pump 30.

Pilot pump 33 and main pump 30 are driven by engine 34. Reference numeral 35 denotes an electromagnetic variable pressure regulating valve (pressure control means; hereinafter, referred to as an electromagnetic regulating valve 35) of the main pump 30, and 36 denotes a pressure regulating valve of the pilot pump 33. In the discharge circuit 40 of the main pump 30, a winch operation valve 42 is provided via a pressure supplementary valve 41. The position A of the winch operation valve 42 is winding up, the position B is neutral, and the position C is winding down.

A hydraulic motor 43 (hereinafter referred to as a hydraulic motor 43) for driving the winch is provided downstream of the winch operating valve 42. A counterbalance valve 70 is provided between the winch operation valve 42 and the hydraulic motor 43. Branch from discharge circuit 40 In the circuit 44, a swash plate pressure control valve 45 is provided in addition to the pressure compensation valve 41. One pilot port 32 a of the LS valve 32 is connected to the discharge circuit 40, and the other pilot port 32 b is connected to the swash plate pressure control valve 4 via an electromagnetic switching valve 46. It is closely related to 5.

The pilot port pressure control valve 50 having the winch operation lever 51 is connected to the discharge circuit 33 a of the pilot pump 33 via the electromagnetic safety valve 52. The electromagnetic safety valve 52 is connected to the safety lock lever 53. The pilot circuit 54 on the upper side of the pilot pressure control valve 50 is connected to the upper side of the winch operation valve 42 via an electromagnetic hoist stop valve 55, and the pilot pressure control valve 50 A pilot circuit 56 on the lower side of the winch is connected to the lower side of the winch operation valve 42.

When the operator leaves the vehicle, operating safety lock lever 53 to set magnetic safety valve 52 to position A closes discharge circuit 33 a of pilot pump 33 and closes The pressure control valve 50 is connected to the tank via the A position of the electromagnetic safety valve 52. Therefore, even if the winch operation lever 51 is operated, the winch operation valve 42 is not switched while maintaining the neutral position B, so that the hydraulic motor 43 does not die and safety is maintained. In the normal working state, the porcelain safety valve 52 is in the B position, and the discharge pressure from the pilot pump 33 is connected to the pilot pressure control valve 50.

The winch hoisting switch 57 that switches to ON or OFF by hydraulic pressure is connected to the pilot circuit 5 of the pilot pressure control valve 50. The winch winding switch 57 and the relay switch 58 are arranged in series on a circuit connecting the battery 59 and the electromagnetic switching valve 46. When pressure acts on the pilot circuit 54, the winch winding switch 57 becomes the switch 0N. The relay switch 58 is turned on by a command from the control device 20. The control device 20 is in contact with the winding position detection sensor 10, the electromagnetic adjustment valve 35 of the main pump 30, the electromagnetic winding stop valve 55, and the coil of the relay switch 58, respectively. .

Next, the hook storage operation will be described with reference to the flowchart of FIG. In step 101, the operator operates the winch operation lever 51 to the winding side, and pressurizes oil from the pilot pump 33 through the pilot circuit 54 and the electromagnetic winding stop valve 55 to winch. It is sent to the operation part 4 2 a of the operation valve 42. As a result, the winch operation valve 42 is switched to the position A on the winding side, and the winch of the hook 6 is wound.

In step 102, if the signal from the winding position detection sensor 10 to the control device 20 is switch ON, that is, if the distance between the hook 6 and the sheave bracket 4 is equal to or greater than the predetermined value L, Return to step 101 to continue winding.

On the other hand, when the distance is equal to or less than the predetermined value L, that is, when the winding position detection sensor 10 is the switch 0FF, the process proceeds to step 103, and the control device 20 sets the electromagnetic winding stop valve 5 Send a signal to 5 and switch the electromagnetic winding stop valve 5 5 from position B to position A to stop winding. That is, the electromagnetic hoisting stop valve 55 closes the hoisting pilot circuit 54 from the pilot pressure control valve 50 and the pilot pressure acting on the winch operating valve 42. Is released into the tank, and the winch operation is stopped by returning the winch operation valve 42 to the neutral position B. At the same time, the controller 10 turns on the overwind alarm LED 21 in response to a signal from the winding position detection sensor 10.

In step 104, the operator turns the overwind alarm release switch 22 ON to turn off the overwind alarm LED21 and turn on the overwind alarm release LED23. In step 105, the overwind alarm release switch 22 receives the signal of 0 N, and the control device 20 switches the electromagnetic hoist stop valve 55 from the A position to the B position, and Open the pilot circuit 54 and release the hoisting stop. Further, the control device 20 sends a signal to the relay switch 58 to connect it.

In step 106, the operator operates the winch operation lever 51 to the winding side. As a result, a pilot pressure is generated in the pilot circuit 54, so that the winch switch 57 is connected. Then, current flows from the battery 59 to the solenoid-operated switching valve 46, and the solenoid-operated switching valve 46 is set to the B position, and the pilot of the LS valve 32 is Shut off LS pressure to port 32b and switch LS valve 32 to position A. By this switching, the pressure oil from the main pump 30 acts on the swash plate control cylinder 31 via the A position of the LS valve 32, and moves the piston 31a to the right in the drawing. By this movement, the discharge amount of the main pump 30 is reduced (step 107). In step 108, the control device 20 sends a signal to the electromagnetic adjustment valve 35 to adjust the set pressure of the discharge line 40 of the main pump 30 to a low pressure, and the main pump 3 The discharge pressure of 0 is reduced. By the above operation, the winch is in a rotating state in which the driving torque is generated by the low pressure at the low rotation speed.

In step 109, the operator sees that the winch winding and the winding of the hook 6 have stopped, and sets the pinch operation lever 51 to the neutral position to complete the storage of the hook. The wire rope 5 is wound up for a short time from the stop of winding up to the neutral position.However, since the winding speed is low and the winding torque is small, even if the wire rope 5 is slightly overwound, the wire rope 5 is not wound. The resulting tension is small. Therefore, the wound wire rope 5 does not bite into the wire port 5 that has been wound on the winch drum, and does not generate turbulence. Further, since the hoisting speed is low, the contact between the hook 6 and the sheave bracket 4 is also low, and damage to both due to impact contact or the like can be prevented.

Note that the order of steps 107 and 108 may be interchanged. Alternatively, the relief pressure may be reduced by reducing the discharge amount of the main pump 30 without providing the electromagnetic adjustment valve 35. Furthermore, the winding position detection sensor 10 can be applied to any sensor that can detect whether or not the distance between the lower surface 8 of the bracket 4 and the upper surface 7 of the hook 6 is larger than a predetermined value L. For example, a general distance sensor such as a mechanical distance gauge or an infrared distance sensor, or a sensor having the same function as the distance sensor may be used. Industrial applicability

According to the present invention, when the hook is wound up and fixed, the wire rope to be wound up is The present invention is useful as a winch overwinding method for a movable crane and a device therefor, which can prevent irregular winding caused by biting into a wire rope already wound on a winch drum.

Claims

The scope of the claims

1. A method for hoisting a movable crane winch, in which a hook for lifting a load is hoisted by a hydraulically driven winch, and the hook is fixed to the hook by contacting the hook with a member at the end of a boom.

When the hook (6) is wound up, when the distance between the hook (6) and the member (4) approached by the winding is reduced to a predetermined value (L) or less, an operation on the hydraulic drive winch is performed. A hydraulically driven crane window characterized in that the dynamic oil pressure and the amount of hydraulic oil are reduced, the coil is further wound in the reduced state, and the hook (6) and the member (4) are abutted and fixed. How to prevent overwinding.

2. A winch winding device for a mobile crane comprising a hydraulic pump, a hydraulic drive winch driven by the hydraulic pump, and a hanging load hook wound up by the hydraulic drive winch,

A winding position detection sensor (10) for detecting a position of the hook (6); a control device (20) for receiving a signal from the winding position detection sensor (10) and transmitting a control signal; A flow control means (31) for reducing the discharge amount of the hydraulic pump (30) in response to the control signal; and a pressure control means (35) for reducing the discharge pressure of the hydraulic pump (30) in response to the control signal. ), A winch overwinding prevention device for a mobile crane.