JPH0930781A - Winch drum lock safety device and control method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent damage to the drum lock device etc. due to erroneous operation of the boom and winch when the winch drum lock device is locked. A crane having a winch operation direction detector 43a, a hoisting operation direction detector 63a, a telescopic operation direction detector 73a, and a drum lock device for mechanically locking the rotation of the winch drum 10 in the lowering direction. In the winch drum lock safety device, a lock state detector 37 for detecting the lock state of the drum lock device and each operation direction detector 43 when this state signal is in the lock state
Control device 7 that outputs an unload command when the signal from any of a, 63a, and 73a is in the winch lowering direction
And this command causes the hydraulic pump to change to the winch motor 1
1, an unloading valve 81 for unloading the discharge pressure to the undulating cylinder 67 and the telescopic cylinder 77. Further, it is preferable to include the control device 7 that outputs a low pressure relief command when a winch winding direction signal is input in the locked state, and a low pressure relief means 55 that lowers the pressure of the winch winding circuit by this command.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum lock safety device for a winch of a crane, and more particularly to a safety device for preventing the winch device from being damaged when the winch and the crane are misoperated in a drum lock state.

[0002]

2. Description of the Related Art Cranes are generally equipped with winch drum lock devices in order to prevent a load from falling. A conventional drum lock device for a general mobile crane will be described below with reference to FIGS. 4 to 5. FIG. 4 is a schematic diagram illustrating a conventional drum lock device. The mobile crane 1 includes an upper revolving structure 3 which is rotatable above a lower traveling structure 2 about an axis in the vertical direction, and has a boom 4 which is capable of hoisting and retracting on the upper revolving structure 3. Further, a driver's cab 5 is provided on the upper swing body 3 for both traveling and operation of the boom 4.

A main winding hook 25 for hanging a load is provided at the tip of the boom 4, and the main winding hook 25 is raised and lowered by winding and lowering the wire rope 12. Depending on the model, some have a supplementary winding hook 26 in addition to the main winding hook 25. Although the following description will be made with respect to the main winding hook, the same applies to the auxiliary winding hook.

The wire rope 1 on the side opposite to the main winding hook 25
The end of 2 is through a load sheave 20 and an idler sheave 21 provided at the tip of the boom 4, a guide roller 22 provided on the upper surface of the boom 4, and a guide sheave 23 provided at the rear end of the boom 4. And is guided to the winch drum 10 for main winding. The winch drum 10 is arranged at the rear end of the upper swing body 3, and the winch motor 11 rotates to wind and lower the wire rope 12.

The operation of hoisting and lowering the wire rope 12 is performed by a winch operating lever (not shown) installed in the operator's cab 5. When the winch operation lever is moved to the neutral position, the winch motor 11 stops rotating.
Therefore, the suspended state of the suspended load can be maintained by placing the winch operation lever in the neutral position while suspending the suspended load on the main winding hook 25. However, in order to prevent the suspended load from falling, a drum lock device is usually provided for safety. I have it. This is because when the drum lock lever 15 installed in the operator cab 5 is set to the lock position, the lock plate 14 meshes with the ratchet 13 provided on the flange portion of the winding drum of the winch drum 10,
This mechanically prevents the winch drum 10 from rotating in the lowering direction. Drum lock lever 15
Are for main winding and auxiliary winding.

FIG. 5 is a detailed view of the drum lock device including the drum lock lever 15, the ratchet 13 of the winch drum 10, the lock plate 14, and the like, which will be described below with reference to FIG. The figure shows an example of operating the drum lock lever 15 in the vertical direction.
The lock release position is indicated by a and 15b. One end of a drum lock cable 16 is connected to the drum lock lever 15, and the other end is connected to one end of the lock plate 14. The lock plate 14 has a rotation center 14c in the middle thereof, and is rotatable around the rotation center 14c. The other end of the lock plate 14 has a shape that meshes with the ratchet 13 of the winch drum 10.

The drum lock lever 15 is locked at the lock position 15
When operated to a, the drum lock cable 16 is pushed,
Along with this, the lock plate 14 rotates around the rotation center 14c to the lock position 14a. At this time, the lock plate 14 meshes with the ratchet 13 of the winch drum 10 to prevent the winch drum 10 from rotating in the lowering direction. However, in this state, the winch drum 10 can freely rotate in the winding direction by the action of the structure of the ratchet 13.

When the drum lock state is unlocked, the winch drum 10 is once rotated to rotate the winch drum 10 to form a gap between the ratchet 13 and the lock plate 14, and then the drum lock lever 15 is locked. It is necessary to operate to the release position 15b. By this operation, the drum lock cable 16 is pulled, and accordingly, the lock plate 14 pivots around the pivot center 14c to the unlock position 14b. Therefore, the winch drum 10 can rotate in the lowering direction.

In this way, the operator operates the drum lock lever 15 to easily perform the drum lock and unlock for preventing the hanging load from falling.
When the main winding hook 25 is not used, for example, when traveling on the road by a mobile crane, the main winding hook 25 is used.
The hook 25 is kept in a retracted state so that the hook 25 does not shake unnecessarily to damage other devices. In this stored state, for example, the hook fixing wheel 27 provided at the front end of the upper swing body 3
The main winding hook 25 is engaged with and fixed to and is held.

[0010]

However, in the above-mentioned conventional mobile crane, when the operator mistakenly operates the drum lock lever 15 to the lock position 15a during the winch lowering operation, the winch drum 10 is rotating.
Suddenly gets mechanically locked. Therefore, an impact force is applied to the winch drum 10, and the ratchet 13 and the lock plate 14 of the winch drum 10 may be damaged. Further, since the impact force at the time of sudden stop is applied to the wire rope 12 as an excessive tension, the wire rope 12 is gradually deteriorated, or in the worst case, the wire rope 12 is broken and an accident such as dropping of a suspended load occurs. There is a risk of

On the contrary, when the winch lowering operation is performed by operating the winch in the lowering direction or operating the boom 4 with the drum lock lever 15 kept in the lock position 15a, Also, similarly to the above, an excessive force is applied to the winch drum 10 and the wire rope 12.

Further, when the main winding hook 25 is in the retracted state, the drum lock lever 15 is normally set to the lock position 1
It is often set to 5a. When the winch is wound up or the boom 4 is raised or extended while the hook is stored, excessive tension may be generated in the wire rope 12 more than necessary. For this purpose, the road sheave 20
There is a risk of damaging the sheave, the guide roller, the hook fixing ring 27, etc. Further, there is a risk that the drum lock device is subjected to an excessive force and the ratchet 13 and the lock plate 14 of the winch drum 10 are damaged in the same manner as described above.

In order to solve the above-mentioned conventional problems, the present invention takes into consideration the allowable condition of the lock state of the winch drum lock device and the operating direction of the winch and boom, and when An object of the present invention is to provide a winch drum lock safety device and a control method therefor capable of preventing the winch device such as a drum lock device, a wire rope and a sheave from being damaged by an erroneous operation of a winch and a boom.

[0014]

SUMMARY OF THE INVENTION A winch drum lock control method according to the present invention relates to a winch drum lock safety device for a crane having a drum lock mechanism for mechanically locking the rotation of the winch drum in the lowering direction. In the control method, while detecting the operation of the drum lock mechanism,
The control method is such that the operation direction of the winch and / or the boom is detected, and the operation of the winch and / or the boom that rotates the winch drum in the lowering direction is not operated when the lock mechanism is in the locked state.

In the winch drum lock safety device according to the present invention, the winch operation direction detector 43a for detecting the operation direction of the winch operation lever 43 for operating the winch motor 11 for rotating the winch drum 10, and the boom hoisting cylinder 67. An up-and-down operation direction detector 63a for detecting an operation direction of an up-and-down operation lever 63 for operating the boom and feet, and a telescopic operation direction detector 73a for detecting an operation direction of the telescopic operation lever 73 for operating the telescopic cylinder 77 of the boom, Further, in a drum lock safety device for a winch of a crane having a drum lock device for mechanically locking the rotation of the winch drum 10 in the lowering direction, a lock state detector 37 for detecting the lock state of the drum lock device, and a lock Winch operation when the status signal from the status detector 37 is in the locked state A control device that outputs an unload command when an operation direction signal from any of the direction detector 43a, the undulation operation direction detector 63a, and the extension / contraction operation direction detector 73a is a direction for rotating the winch drum 10 in the lowering direction. 7 and an unload valve 81 for unloading the discharge pressure from the hydraulic pump to the winch motor 11, the undulating cylinder 67 and the telescopic cylinder 77 when the unload command is input.

The winch drum lock safety device described above includes a winch operation direction detector 43a for detecting the operation direction of the winch operation lever 43, and a winch operation lever 43 for determining the direction and flow rate of the pressure oil discharged from the hydraulic pump. Directional control valve 41 for controlling the winch, a winch motor 11 for rotating the winch drum 10, which is controlled by the directional control valve 41, and a winch drum 10.
In a drum lock safety device for a winch of a crane having a drum lock device for mechanically locking the rotation of the drum in the lowering direction, a lock condition detector 37 for detecting the lock condition of the drum lock device, and a lock condition detector 37. When the winch operation direction detector 43a inputs a winch hoisting direction signal when the status signal from the device is in the locked state, the controller 7 outputs a low pressure relief command of the winch hoisting circuit, and the direction when the low pressure relief command is input. It is desirable to provide low pressure relief means 55 for reducing the pressure of the winch winding circuit between the switching valve 41 and the winch motor 11.

In the above winch drum lock safety device, the lock state detector 37 is the winch drum 10
The drum lock lever position detector 31 for detecting the operation position of the drum lock lever 15 for mechanically locking the rotation of the winch drum 10 in the lowering direction, and the lowering of the winch drum 10 by operating the drum lock lever 15. A lock plate position detector 32 that detects the position of the lock plate 14 that mechanically locks the rotation in the direction, and the controller 7 includes a drum lock lever position detector 31 and a lock plate position detector 32. The abnormality detection signal may be output when the two position signals from 1 to 3 do not match.

[0018]

When the drum lock device is in the locked state of the winch drum and the winch operation and the boom up / down operation for rotating the winch drum in the hoisting direction are performed, the discharge from the hydraulic pump is performed. Unload pressure. As a result, since the winch and boom working machines cannot operate, an excessive force is not applied to the drum lock device, the wire rope, and the like. Therefore, it is possible to prevent each winch device from being damaged.

When the winch drum is locked by the drum lock device and a winch operation is performed to rotate the winch drum in the hoisting direction, the winch hoisting circuit is set to a low pressure. This allows
Since the rotation torque of the winch motor becomes small, the tension of the wire rope does not become excessive even if the winding operation is mistakenly performed with the hook retracted. Therefore, it is possible to prevent an excessive force from being applied to the hook fixing portion, the wire rope, each sheave, and the like, and to prevent each winch device from being damaged.

The lock state detector of the drum lock device is
When it is composed of the drum lock lever position detector and the lock plate position detector, if both position signals from the drum lock lever position detector and the lock plate position detector do not match, it is regarded as abnormal, and the safety device The reliability can be improved.

[0021]

EXAMPLES Examples will be described below with reference to FIGS. FIG. 1 is a control circuit block diagram showing the present embodiment. Similarly to the conventional case, the drum lock lever 15 is provided in the operator's cab, and the drum lock lever position detector 31 for detecting the operation position of the drum lock lever 15 is provided. In this embodiment, the operation of the drum lock lever 15 is tilted to the lock position 15a and the lock release position 15b with the intermediate portion as a fulcrum as shown in the figure. One end of the drum lock cable 16 is connected to the end of the drum lock lever 15, and the one end of the drum lock cable 16 can be pulled or pushed by the operation thereof. The drum lock lever 15 is not limited to this, and may be operated in the vertical direction as in the conventional case.

The other end of the drum lock cable 16 is connected to one end of the lock plate 14. When the drum lock lever 15 is operated, the lock plate 14 is rotated around the rotation center 14c in the middle portion thereof. Along with this, the other end of the lock plate 14 meshes with the ratchet 13 of the winch drum 10 to lock the winch drum 10, or disengages from the ratchet 13 to release the lock. Further, a lock plate position detector 32 for detecting whether the lock plate 14 is in the locked position 14a or the unlocked position 14b is provided.

The drum lock lever position detector 31 and the lock plate position detector 32 may be constituted by, for example, limit switches or proximity switches. These position detection signals are input to the control device 7. In this embodiment, as described above, the lock state detector 3 of the drum lock device is used.
Although 7 is composed of the drum lock lever position detector 31 and the lock plate position detector 32, it may be composed of only one of them.

A drum lock lever shutoff device 33 is provided near the drum lock lever 15. This prevents the drum lock lever 15 from being operated from the unlocked position 15b to the locked position 15a when the predetermined condition is not satisfied. In this embodiment, a hydraulic cylinder is used for the drum lock lever shutoff device 33, and when this hydraulic cylinder extends, its rod side is inserted between the unlocked position 15b and the locked position 15a of the drum lock lever 15. It has become. Hereinafter, this hydraulic cylinder is referred to as a hydraulic cylinder 33. The hydraulic cylinder 3
3 has a spring on the head side, and the hydraulic oil flowing into the bottom side expands the hydraulic cylinder 33 while reducing the spring, but the present invention is not limited to the hydraulic cylinder of this structure.

The direction switching valve 34 is a solenoid valve for controlling the on / off direction of the pressure oil flowing into the hydraulic cylinder 33 for shutting off the drum lock lever. The input port of the direction switching valve 34 is connected to the hydraulic pump 35, and the output port thereof is connected to the bottom side of the hydraulic cylinder 33. The pressure oil return port of the direction switching valve 34 is connected to the tank 36.
An ON / OFF switching signal output from the control device 7 is connected to the operation solenoid portion 34c.

The winch drum 10 is rotated by a winch motor 11 composed of a hydraulic motor capable of rotating in both directions. The winch motor 11 is controlled in flow rate by the direction switching valve 41 to control the rotation speed. The pressure oil discharged from the hydraulic pump 44 passes through the pipe 45 and the direction switching valve 41.
Of the directional control valve 41, and the output port of the directional control valve 41 is connected to the winch motor 11 via the pipe line 46 and the pipe line 47. Further, a check valve 48 and a counter balance valve 49 are inserted in the pipe line 47, and the check valve 4
Reference numeral 8 allows pressure oil to pass when the winch motor 11 rotates in the winding direction, and counter balance valve 49 allows pressure oil to pass when rotating the winch motor 11 in the winding direction. Direction switching valve 4
A hydraulic signal from the operation valve 42 is connected to the first operation unit 41d and the first operation unit 41e.

The operation valve 42 is operated by the winch operation lever 43, and the pilot oil pressure signal from the hydraulic pump 35 is controlled to the pilot oil pressure signal of the pressure corresponding to the operation amount of the winch operation lever 43 to operate the directional control valve 41. Four
1d and the operation unit 41e. Winch operating lever 43
When the valve is operated, the operation valve 42 causes a spring force that always urges the input port of the pilot hydraulic signal from the hydraulic pump 35 and the output port of the directional control valve 41 to the operation portion 41d or the operation portion 41e to be in a closed state. Against this, the input port and the output port are made to communicate with each other. The winch operation lever 43 is a winch operation direction detector 43 that detects whether the operation direction is the winding direction or the winding direction.
The winch operation direction detector 43a has a and outputs an operation direction signal to the control device 7.

A low pressure relief means 55 of a winch winding circuit is provided in the middle of the pipe line 47. That is, the conduit 47
Is branched through a pipe line 52, and the pipe line 52 is connected to a low pressure relief valve 51 via a switching valve 50. A low pressure relief signal from the control device 7 is connected to the operation unit 50c of the switching valve 50. When the low pressure relief signal is not input, the switching valve 50 switches to the 50b position to communicate the pipe line 52 with the low pressure relief valve 51, and when the low pressure relief signal is input, switches to the 50a position. The pressure oil from the pipe line 52 is shut off by a built-in check valve. The low pressure relief valve 51 is the winch motor 1
The relief pressure value is set so as to communicate at a pressure lower than the normal operating pressure of 1, and the relief oil is drained to the tank 36.

A hoisting cylinder 67 for hoisting the boom 4.
The flow rate is controlled by the direction switching valve 61 to control the undulation speed. The pressure oil discharged from the hydraulic pump 64 is connected to the input port of the directional switching valve 61 via the pipe 65, and the output port of the directional switching valve 61 is undulated by the undulating cylinder 67 via the pipe 66 and the pipe 68, respectively. Is connected to the bottom side and the head side. The pilot hydraulic pressure signal from the operation valve 62 is connected to the operation unit 61d and the operation unit 61e of the direction switching valve 61.

The operation valve 62 is operated by the up-and-down operation lever 63, and the pilot oil pressure signal from the hydraulic pump 35 is controlled to the pilot oil pressure signal having a pressure corresponding to the operation amount of the up-and-down operation lever 63 to operate the operation portion of the directional control valve 61. It leads to 61d and the operation part 61e. When the up-and-down operation lever 63 is operated, the operation valve 62 keeps the input port of the pilot hydraulic signal from the hydraulic pump 35 and the output port to the operation portion 61d or the operation portion 61e of the directional control valve 61 always closed. The input port and the output port are made to communicate with each other against the biasing spring force. Further, the undulation operation lever 63 has an undulation operation direction detector 63 a that detects whether the operation direction is the upright direction or the lie direction, and the undulation operation direction detector 63 a outputs an operation direction signal to the control device 7.

Telescopic cylinder 77 for telescopically boom 4
The flow rate is controlled by the direction switching valve 71 to control the expansion / contraction speed. The pressure oil discharged from the hydraulic pump 64 is connected to the input port of the directional switching valve 71 via the pipeline 75 branched from the pipeline 65, and the output port of the directional switching valve 71 connects the pipeline 76 and the pipeline 78. It is connected to the bottom side and the head side of the telescopic cylinder 77 through the respective units. The pilot hydraulic signal from the operation valve 72 is connected to the operation portions 71d and 71e of the direction switching valve 71.

The operation valve 72 is operated by the expansion / contraction operation lever 73, and the pilot oil pressure signal from the hydraulic pump 35 is controlled to a pilot oil pressure signal of a pressure corresponding to the operation amount of the expansion / contraction operation lever 73 to operate the directional control valve 71. 71d and the operation part 71e. When the expansion / contraction operation lever 73 is operated, the operation valve 72 causes the input port of the pilot hydraulic signal from the hydraulic pump 35 and the operation port 71d of the directional control valve 71 or the output port to the operation unit 71e to be constantly closed. The input port and the output port are made to communicate with each other against the biasing spring force. Further, the expansion / contraction operation lever 73 has an expansion / contraction operation direction detector 73a for detecting whether the operation direction is an expansion direction or a contraction direction, and the expansion / contraction operation direction detector 73a outputs an operation direction signal to the control device 7.

The pipe 45 branches into a pipe 82 on the way,
Unload valve 81 via check valve 83 and conduit 86
Connected to the input port of In addition, the pipeline 65 and the pipeline 7
5 branches into a conduit 84 in the middle of the common conduit 65, merges with a conduit 86 via a check valve 85, and is connected to an input port of the unload valve 81 similar to the above. The output port of the unload valve 81 is connected to the tank 36. The unload valve 81 connects the input port and the output port when it is in the 81a position, and shuts off between the input port and the output port by the built-in check valve when it is in the 81b position. A switching control signal from the control device 7 is connected to the operation portion 81c of the unload valve 81. The check valve 83 and the check valve 85 prevent the pressure oils from the conduits 82 and 84 from flowing back to each other via the conduit 86 at the junction.

The winch operation direction detector 43a, the undulation operation direction detector 63a, and the extension / contraction operation direction detector 73a are, for example, electrically constituted by limit switches, and when operated in the winding direction or the winding direction, respectively. It is also possible to output a signal that operates in response to. Alternatively, the pressure of the pilot hydraulic signal to the operating portion 41d or the operating portion 41e of the directional control valve 41 may be hydraulically detected by the pressure switch, and the signal of the pressure switch that operates depending on the operating direction may be output. .

The control device 7 is composed of a microcomputer system which uses, for example, a microcomputer (hereinafter referred to as CPU) as its core. That is, the control device 7
In addition to the CPU, is a ROM that stores a system execution program, and an R that stores control data and calculation results.
An AM, an input / output interface section for input / output with the outside, and the like are provided.

The alarm buzzer 8 informs the operator when the winch safety device detects an abnormality.
It is activated by the alarm output signal from.

Next, the operation of the above circuit will be described. Now, the operation solenoid portion 34c of the direction switching valve 34
It is assumed that a command to turn off the hydraulic cylinder 33 is input from the control device 7. At this time, the direction switching valve 34 is at the switching position 34a, the pressure oil from the hydraulic pump 35 is shut off, and the oil on the bottom side of the hydraulic cylinder 33 is drained to the tank 36. Therefore, the hydraulic cylinder 33 is contracted by the expanding force of the spring on the head side, and the drum lock lever 15 can be switched.

Further, it is assumed that a low pressure relief signal is not input from the control device 7 to the operating portion 50c of the switching valve 50. That is, the switching valve 50 is at the position 50a, the pressure oil from the pipe line 52 is shut off, and the low pressure relief valve 51
Is not working. Further, it is assumed that the unload signal is not input from the control device 7 to the operation portion 81c of the unload valve 81, and the unload valve 81 is at the position 81b and the conduit 86 via the conduit 82 and the conduit 84. Pressure oil from shall be cut off.

When the drum lock lever 15 is operated to the unlock position 15b, the lock plate 14 is rotated to the unlock position 14b. At this time, the winch drum 10
Becomes a rotatable state and can be rotated by the forward and reverse rotation of the winch motor 11. Further, the drum lock lever position detector 31 and the lock plate position detector 32 are
An unlock position signal is output to the control device 7, respectively.

When the winch operation lever 43 is operated in the hoisting direction, the operation valve 42 operates as an input port for the pilot hydraulic signal from the hydraulic pump 35 and the operating portion 41 of the direction switching valve 41.
The input port and the output port are made to communicate with each other against the spring force that normally urges the output port to the output port d to be closed. At this time, a pilot hydraulic signal having a pressure corresponding to the operation amount of the winch operation lever 43 is output to the operation unit 41d. Therefore, the direction switching valve 41 is switched to the position 41a, the pressure oil discharged from the hydraulic pump 44 is guided to the direction switching valve 41 through the pipe 45, and the winch operating lever 43 is operated.
The flow rate of the pressure oil corresponding to the operation amount of the inflow motor flows into the winch motor 11 via the check valve 48 and the pipe line 47, and the return oil flowing out from the winch motor 11 flows into the tank 36 via the pipe line 46 and the direction switching valve 41. Is drained to. In this way, the winch motor 11 rotates in the winding direction at a speed corresponding to the operation amount of the winch operation lever 43, and the winch drum 10 winds the winch wire 12. Further, a winch operation direction detector 43a outputs a winding direction signal, which is input to the control device 7.

Further, when the winch operation lever 43 is operated in the lowering direction, the operation valve 42 similarly similarly resists the spring force for urging it to the normally closed state, and the input port of the pilot hydraulic pressure signal from the hydraulic pump 35. And the output port of the direction switching valve 41 to the operation portion 41e are connected. At this time, a hydraulic signal of a pressure corresponding to the operation amount of the winch operation lever 43 is output to the operation unit 41e. Therefore, the directional control valve 41
Is switched to the 41c position, the pressure oil discharged from the hydraulic pump 44 is guided to the direction switching valve 41 via the pipe line 45,
The pressure oil having a flow rate corresponding to the operation amount of the winch operation lever 43 flows into the winch motor 11 through the pipe line 46, and the return oil flowing out from the winch motor 11 includes the pipe line 47, the counter balance valve 49, and the direction switching valve 41. Through the tank 36
Drained. In this way, the winch motor 1
1 rotates in the lowering direction at a speed according to the operation amount of the winch operating lever 43, and the winch drum 10 lowers the winch wire 12. Also, the winch operation direction detector 4
A lowering direction signal is output from 3a and input to the control device 7.

When the winch operation lever 43 is returned to the neutral position, the operation valve 42 receives the pilot hydraulic pressure signal from the hydraulic pump 35 by the spring force and the directional control valve 41.
The output port to the operation unit 41d or the operation unit 41e is disconnected. Therefore, the directional control valve 41 has the neutral position 41.
Switching to b, the inflow of pressure oil to the winch motor 11 and the outflow of pressure oil from the winch motor 11 are blocked, and the rotation of the winch motor 11 is stopped. At this time, the counterbalance valve 49 completely shuts off the oil flow in the lowering direction of the winch motor 11, so that the suspended load is prevented from falling naturally. Further, the hoisting direction signal and the hoisting direction signal from the winch operation direction detector 43a are not output.

When a low pressure relief signal is output from the control device 7 to the operating portion 50c of the switching valve 50, the switching valve 50 is turned off.
Switching to the b position, the pressure oil in the conduit 47 is guided to the low pressure relief valve 51 via the conduit 52 and the switching valve 50. Therefore, when the winch operation lever 43 is wound up, the pipe 47
Is introduced into the low pressure relief valve 51, and the circuit pressure at that time is suppressed to a circuit pressure set to a lower pressure than during normal operation.

Set the drum lock lever 15 to the lock position 15
When operated to a, the lock plate 14 moves to the lock position 14
Rotate to a. At this time, the lock plate 14 and the ratchet 13 mesh with each other, and the winch drum 10 cannot rotate in the lowering direction. Further, the drum lock lever position detector 31 and the lock plate position detector 32 each output a lock position signal to the control device 7.

When the control device 7 outputs an ON command for the hydraulic cylinder 33 to the operation solenoid portion 34c of the direction switching valve 34 when the drum lock lever 15 is in the unlock position 15b, the direction switching valve 34 is switched to the switching position 34b. Switch to. At this time, the pressure oil from the hydraulic pump 35 flows into the bottom side of the hydraulic cylinder 33 via the direction switching valve 34. The hydraulic cylinder 33 extends against the expansion force of the spring on the head side, and the drum lock lever 15 moves to the lock position 15a.
Cannot be switched to.

When the boom up / down operation lever 63 is operated in the down direction, the operation valve 62 causes the operation port 6 of the direction switching valve 61 and the input port of the pilot hydraulic signal from the hydraulic pump 35.
The input port and the output port are made to communicate with each other against the spring force that constantly urges the output port to 1d to be in a shut-off state. At this time, a pilot hydraulic pressure signal having a pressure corresponding to the operation amount of the up-and-down operation lever 63 is output to the operation portion 61d. Therefore, the direction switching valve 61 is switched to the 61a position, the pressure oil discharged from the hydraulic pump 64 is guided to the direction switching valve 61 via the pipe line 65, and the pressure of the flow rate corresponding to the operation amount of the up-and-down operation lever 63 is changed. The oil flows into the head side of the undulating cylinder 67 via the pipe line 68, and the return oil flowing out from the bottom side of the undulating cylinder 67 is drained to the tank 36 via the pipe line 66 and the direction switching valve 61. In this way,
The hoisting cylinder 67 contracts at a speed corresponding to the operation amount of the hoisting operation lever 63 to turn the boom 4 down. Further, a lie-down operation direction detector 63a outputs a lie-down direction signal, which is input to the control device 7.

When the up-and-down operating lever 63 is operated in the up-and-down direction, similarly, a pilot hydraulic pressure signal having a pressure corresponding to the operation amount of the up-and-down operating lever 63 is guided to the operating portion 61e of the direction switching valve 61. Therefore, the directional control valve 61 has 6
The pressure oil discharged from the hydraulic pump 64 is guided to the direction switching valve 61 via the pipe line 65, and the pressure oil having a flow rate corresponding to the operation amount of the up-and-down operation lever 63 is changed to the 1c position.
The return oil, which flows into the bottom side of the undulating cylinder 67 via the, and flows out from the head side of the undulating cylinder 67, is drained to the tank 36 via the pipe line 68 and the direction switching valve 61. In this way, the hoisting cylinder 67 extends at a speed corresponding to the operation amount of the hoisting operation lever 63, and hoists the boom 4. In addition, the up-and-down operation direction detector 63a outputs an up-and-down direction signal, which is input to the control device 7.

When the hoisting operation lever 63 is returned to the neutral position,
The operation valve 62 blocks the input port of the pilot oil pressure signal from the hydraulic pump 35 and the output port of the direction switching valve 61 to the operation portion 61d or the operation portion 61e by the spring force. Therefore, the direction switching valve 61 is switched to the neutral position 61b, the pressure oil inflow to the undulation cylinder 67 and the pressure oil outflow from the undulation cylinder 67 are blocked, and the undulation cylinder 6
The reduction and extension operations of 7 are stopped. Further, the lie-down direction signal and the erection-direction signal from the undulation operation direction detector 63a are not output.

When the boom extension / contraction operation lever 73 is operated in the contraction direction, the operation valve 72 causes the operation port 7 of the directional control valve 71 and the input port of the pilot hydraulic pressure signal from the hydraulic pump 35.
The input port and the output port are made to communicate with each other against the spring force that constantly urges the output port to 1d to be in a shut-off state. At this time, a pilot hydraulic pressure signal having a pressure corresponding to the operation amount of the extension / contraction operation lever 73 is output to the operation unit 71d. Therefore, the direction switching valve 71 is switched to the position 71a, the pressure oil discharged from the hydraulic pump 64 is guided to the direction switching valve 71 through the pipe line 75, and the pressure of the flow rate corresponding to the operation amount of the telescopic operation lever 73 is changed. The oil flows into the head side of the telescopic cylinder 77 via the pipe 78, and the return oil flowing out from the bottom side of the telescopic cylinder 77 is drained to the tank 36 via the pipe 76 and the direction switching valve 71. In this way,
The telescopic cylinder 77 contracts at a speed corresponding to the operation amount of the telescopic operation lever 73, and contracts the boom 4. A contraction direction signal is output from the expansion / contraction operation direction detector 73a and is input to the control device 7.

When the expansion / contraction operation lever 73 is operated in the extension direction, similarly, a pilot hydraulic pressure signal having a pressure corresponding to the operation amount of the expansion / contraction operation lever 73 is guided to the operation portion 71e of the direction switching valve 71. Therefore, the direction switching valve 71 is
The pressure oil discharged from the hydraulic pump 64 is switched to the 1c position and is guided to the direction switching valve 71 through the pipe line 75, and the pressure oil having a flow rate according to the operation amount of the expansion / contraction operation lever 73 is supplied to the pipe line 76.
The return oil that flows into the bottom side of the telescopic cylinder 77 via the, and flows out from the head side of the telescopic cylinder 77 is drained to the tank 36 via the pipe line 78 and the direction switching valve 71. In this way, the telescopic cylinder 77 extends at a speed according to the operation amount of the telescopic operation lever 73, and extends the boom 4. Further, a stretching direction signal is output from the stretching operation direction detector 73a and is input to the control device 7.

When the telescopic operation lever 73 is returned to the neutral position,
The operation valve 72 blocks the input port of the pilot oil pressure signal from the hydraulic pump 35 and the output port of the direction switching valve 71 to the operation portion 71d or the operation portion 71e by the spring force. Therefore, the direction switching valve 71 is switched to the neutral position 71b, the pressure oil inflow to the telescopic cylinder 77 and the pressure oil outflow from the telescopic cylinder 77 are blocked, and the telescopic cylinder 7
The reduction and extension operations of 7 are stopped. Further, the contraction direction signal and the expansion direction signal from the expansion / contraction operation direction detector 73a are not output.

When an unload signal is output from the control device 7 to the operation portion 81c of the unload valve 81, the unload valve 81 is switched to the 81a position, and the pipe line 86 communicates with the tank 36. At this time, the pressure oil in the pipeline 45 passes through the pipeline 82, the check valve 83, and the pipeline 86, and the tank 3
6 is drained, the pressure oil from the hydraulic pump 44 is not supplied to the winch motor 11. Therefore, the winch motor 11 does not rotate even if the winch operation lever 43 is wound up or down.

Further, similarly to the above, the pressure oil in the pipe line 65 is drained to the tank 36 via the pipe line 84, the check valve 85 and the pipe line 86, so that the pressure oil from the hydraulic pump 64 is undulated. 67 and the telescopic cylinder 77 are no longer supplied. Therefore, even if the up-and-down operating lever 63 or the telescopic operating lever 73 is operated, the up-and-down cylinder 67 and the telescopic cylinder 77 do not operate.

Next, an abnormality detection flow of the control device 7 of the drum lock safety device according to the present invention having the above-mentioned configuration will be described. Although the judgment conditions for detecting anomalies differ depending on the model, etc. of which the mechanical structure of the crane is different,
FIG. 2 is a table showing an example of the determination condition. FIG.
In ∘, a circle represents a condition in which there is no problem even if the simultaneous operations are performed, and a cross represents a dangerous condition in which there are problems in the simultaneous operations. The control device 7 performs abnormality detection based on this determination condition.

FIG. 3 shows an example of an abnormality detection flowchart based on the determination condition of FIG. 2, which will be described below with reference to FIG. In addition, the following flow processing is performed by the CP of the control device 7.
It is assumed that U performs it every predetermined period. (Step 101) Drum lock lever position detector 31
Is inputted to determine whether or not the drum lock lever 15 is on (locked state). When the drum lock lever 15 is on, the routine proceeds to step 102, and when it is off, the routine proceeds to step 103. (Step 102) A position signal from the lock plate position detector 32 is input to determine whether the lock plate 14 is on (locked state), and when it is on, step 105
If it is off, proceed to step 104.

(Step 103) The position signal from the lock plate position detector 32 is input to the lock plate 14
Is off (unlocked state), the process proceeds to step 111 when it is off, and step 104 when it is on.
Proceed to. (Step 104) Since the position of the drum lock lever 15 and the position of the lock plate 14 do not coincide with each other, it is determined to be abnormal, and the alarm buzzer 8 notifies the abnormality. afterwards,
Go to step 105.

(Step 105) An operation direction signal is input from the winch operation direction detector 43a, and when the operation direction is "winding", the process proceeds to step 106, when "winding", the process proceeds to step 109, and the "neutral position". In case of “”, the process proceeds to step 107. (Step 106) A low pressure relief command is output to the switching valve 50 of the winch hydraulic circuit to switch to the 50b position, and the low pressure relief valve 51 is operated to lower the operating pressure of the winch motor 11. Then, it progresses to step 107.

(Step 107) Undulating operation direction detector 6
An operation direction signal is input from 3a, and if the operation direction is "down", the process proceeds to step 109, and if not, the process proceeds to step 108. (Step 108) An operation direction signal is input from the expansion / contraction operation direction detector 73a, and if the operation direction is "extend", the process proceeds to step 109, and if not, the process proceeds to end and the process ends.

(Step 109) It is judged as abnormal according to the judgment condition of FIG. 2, and the alarm buzzer 8 notifies the abnormality,
Go to step 110. (Step 110) An unload command is output to the unload valve 81 to switch to the 81a position. As a result, the pressure oil from the hydraulic pump 44 and the pressure oil from the hydraulic pump 64 are not supplied to the winch motor 11, the hoisting cylinder 67 and the telescopic cylinder 77, respectively. Therefore, the winch motor 11, the hoisting cylinder 67 and the telescopic cylinder 77.
Will stop operating. After that, the process proceeds to the end, and the processing ends.

(Step 111) The low pressure relief command output to the switching valve 50 of the winch hydraulic circuit is turned off and switched to the position 50a, and the operating pressure of the winch motor 11 is returned to the normal value. Then, it progresses to step 112. (Step 112) An operation direction signal is input from the winch operation direction detector 43a, and if the operation direction is "winding down", the process proceeds to step 113, and if not, step 11
Go to 4.

(Step 113) The hydraulic cylinder 33 for shutting off the drum lock lever is turned on (in the shut-off state) so that the drum lock lever 15 is not turned on (lock release position) and turned on (lock position). Then, the process returns to step 112 and waits until the winch lowering operation is completed. (Step 114) The drum lock lever shutoff hydraulic cylinder 33 is turned off to release the shutoff state, and the process ends.

Controlling according to the above processing flow is as follows. When at least one of the drum lock lever 15 and the lock plate 14 is in the lock position, in steps 105, 107 and 108, as shown in FIG.
It is checked whether the operation direction of the winch and the boom is a direction that damages the winch device based on the determination condition shown in. When an abnormality is detected, an alarm is issued in step 109 and an unload command is output in step 110 to stop the operation of the work machine.

Further, in step 105, it is checked whether or not it is a winch hoisting operation, and when the winch hoisting operation is performed, a low pressure relief command is output to make the winch circuit a low pressure and the tension applied to the wire rope at the start of hoisting is reduced. Then, when the drum lock lever 15 and the lock plate 14 reach the unlocked position, step 11
At 1, the low pressure relief command is turned off to return the winch circuit to the normal operating pressure, and a predetermined winch operation becomes possible.

After that, when the winch lowering operation is performed, the routine proceeds from step 112 to step 113, and the drum lock lever blocking device 33 is turned on (blocking state). This prevents the drum lock lever 15 from moving to the lock position 15a during the winch lowering operation. When the winch lowering operation is completed, the drum lock lever shutoff device 33 is turned off (released) in step 114.

When the operating position of the drum lock lever 15 and the position of the lock plate 14 do not match,
In step 104, an abnormality alarm is output to prompt the operator to deal with the abnormality.

Lock state detector 37 of drum lock device
If is composed of either one of the drum lock lever position detector 31 and the lock plate position detector 32,
It is no longer necessary to check if both position signals match. At this time, step 101 of the above flowchart
In the case of the lock state detector 37, the lock state detector 37 is used to determine whether the lock state or not.
If not, the process may proceed to step 111. In this way, the actions and effects described above remain unchanged.

In the above description, the drum lock lever blocking device 33 is provided so that the winch drum is not locked during the winch lowering operation. However, this is not the gist of the present invention, and the lock plate 14
A lock plate blocking device (not shown) may be provided to prevent the lock release position 14b from moving from the lock release position 14b to the lock position 14a.

[0068]

When the drum lock device is in the locked state and the winch operation for rotating the winch drum in the lowering direction and the boom up / down operation are performed, the discharge pressure from the hydraulic pump is reduced. To unload. As a result, since the working machine cannot be operated, an excessive force is not applied to the drum lock device, the wire rope and the like. Therefore, it is possible to prevent each device from being damaged.

Also, when the drum lock device is in the locked state and the winch operation for rotating the winch drum in the winding direction is performed, the winch winding circuit is set to a low pressure. Therefore, since the tension of the wire rope does not become excessive, an excessive force is not applied to the hook fixing portion, the wire rope, each sheave, etc. when the hook is stored. Therefore, it is possible to prevent each device from being damaged.

The lock state detector of the drum lock device is
When it is composed of the drum lock lever position detector and the lock plate position detector, if both position signals from the drum lock lever position detector and the lock plate position detector do not match, it is regarded as abnormal, and the safety device The reliability can be improved.

[Brief description of drawings]

FIG. 1 is a control circuit block diagram showing an embodiment of the present invention.

FIG. 2 shows an example of determination conditions for abnormality detection of a control device that represents an embodiment of the present invention.

FIG. 3 shows an example of an abnormality detection flowchart of a control device representing an embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a conventional drum lock device.

FIG. 5 is a detailed explanatory diagram of a conventional drum lock device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mobile crane, 2 ... Lower traveling body, 3 ... Upper swing body, 4 ... Boom, 5 ... Operator's cab, 7 ... Control device, 8 ... Alarm buzzer, 10 ... Winch drum, 11 ... Winch motor, 12 ... Wire Rope, 13 ... Ratchet, 14 ... Lock plate, 15 ... Drum lock lever, 16 ... Drum lock cable, 20 ... Load sheave, 21 ... Idler sheave, 22 ... Guide roller, 23 ... Guide sheave,
25 ... Main winding hook, 26 ... Supplementary winding hook, 27 ... Hook fixed wheel, 31 ... Drum lock lever position detector, 32 ... Lock plate position detector, 33 ... Drum lock lever shutoff device, 34 ... Direction switching valve, 35 … Hydraulic pump, 36…
Tank, 37 ... lock state detector, 41 ... direction switching valve,
42 ... Operation valve, 43 ... Winch operation lever, 43a ... Winch operation direction detector, 44 ... Hydraulic pump, 45, 4
6, 47 ... Pipe line, 48 ... Check valve, 49 ... Counter balance valve, 50 ... Switching valve, 51 ... Low pressure relief valve, 52
... Pipe line, 55 ... Low-pressure relief means, 61 ... Direction switching valve,
62 ... Operation valve, 63 ... Elevation operation lever, 63a ... Elevation operation direction detector, 64 ... Hydraulic pump, 65, 66 ... Pipe line,
67 ... undulating cylinder, 68 ... pipeline, 71 ... direction switching valve,
72 ... Operation valve, 73 ... Telescopic operation lever, 73a ... Telescopic operation direction detector, 75, 76 ... Pipe line, 77 ... Telescopic cylinder, 78 ... Pipe line, 81 ... Unload valve, 82 ... Pipe line, 8
3 ... Check valve, 84 ... Pipe line, 85 ... Check valve, 86
... pipe.

Claims (4)

[Claims] 1. A method of controlling a drum lock safety device for a winch of a crane having a drum lock mechanism for mechanically locking rotation of a winch drum in a lowering direction, the operation of the drum lock mechanism is detected, and the winch and And / or winch drum lock safety, characterized in that the operation direction of the boom is detected, and the operation of the winch and / or boom for rotating the winch drum in the lowering direction is not operated when the lock mechanism is in the locked state. Device control method. 2. A winch operation direction detector (43a) for detecting an operation direction of a winch operation lever (43) for operating a winch motor (11) for rotating a winch drum (10), and a boom hoisting cylinder (67). Telescopic operating direction detector (63a) that detects the operating direction of the undulating operating lever (63) and telescopic operating direction that detects the operating direction of the telescopic operating lever (73) that operates the telescopic cylinder (77) of the boom. A crane winch drum lock safety device having a detector (73a) and a drum lock device for mechanically locking the rotation of the winch drum (10) in the lowering direction. The lock state detector (37) for detecting the state, and the winch operation direction detector (43a), the undulation operation direction detector (63a) and the expansion / contraction when the state signal from the lock state detector (37) indicates the lock state. Operation direction detector (73a) When the operation direction signal from either one is the direction to rotate the winch drum (10) in the lowering direction, the control device (7) that outputs an unload command, and when this unload command is input, the winch motor from the hydraulic pump (11), undulating cylinder (67) and telescopic cylinder (77)
A winch drum lock safety device comprising an unload valve (81) for unloading the discharge pressure to the winch. 3. A winch operation direction detector (43a) for detecting the operation direction of the winch operation lever (43), and a winch operation lever (4a) for detecting the direction and flow rate of the pressure oil discharged from the hydraulic pump.
Directional switching valve for winch (41) controlled according to the operation amount of 3)
And a winch drum controlled by a directional valve (41)
A winch drum lock safety device for a crane, comprising: a winch motor (11) for rotating (10) and a drum lock device for mechanically locking the rotation of the winch drum (10) in the lowering direction. When the winch hoisting direction signal is input from the winch operation direction detector (43a) when the lock state detector (37) that detects the lock state of the and the state signal from the lock state detector (37) is in the lock state. , A control device (7) that outputs a low pressure relief command for the winch hoisting circuit, and a low pressure relief that lowers the winch hoisting circuit between the directional control valve (41) and the winch motor (11) when this low pressure relief command is input. A winch drum lock safety device comprising means (55). 4. The lock state detector (37) detects an operating position of a drum lock lever (15) for mechanically locking the rotation of the winch drum (10) in the lowering direction. Drum lock lever position detector (31)
And the winch drum by operating the drum lock lever (15).
A lock plate position detector (3 that detects the position of the lock plate (14) that mechanically locks the rotation of (10) in the unwinding direction.
2) and the control device (7), when the position signals from the drum lock lever position detector (31) and the lock plate position detector (32) do not match,
The winch drum lock safety device according to claim 2 or 3, wherein an abnormality detection signal is output.