JPH0711109Y2 - Automatic braking device for mobile cranes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an automatic braking device for a mobile crane.

[Prior Art] One of the ground improvement methods using a mobile crane is a dynamic consolidation method. This method is a method in which a weight that is lifted by a lifting winch via a hook is allowed to freely fall together with the hook, and the soft ground is hardened by the impact of the weight.

[Problems to be solved by the invention] In the dynamic consolidation method, the hook is dropped together with the weight. Therefore, the operator operates the brake device of the lifting winch to lift the hook at the moment the weight is landed. You need to brake the winch to stop the hook from falling,
Conventionally, this operation relies visually on the intuition of the operator, so the timing is extremely difficult. If the brakes are braked before the weights land, an excessive load may be applied to the machine and the winch may be damaged.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an automatic braking device for a mobile crane that does not require the intuition of an operator.

[Means for Solving the Problem] The present invention is directed to a revolving structure 2 which is rotatably disposed on a traveling structure 3.
A jib 4 which is rotatably supported by the revolving structure 2 and which can be raised and lowered by a hoisting winch 5, and a jib 4 which is suspended from the tip of the jib 4 so that it can be hoisted down by a hoisting winch 12 and a ground 17. In a mobile crane 1 equipped with a hook 15 capable of suspending a weight 16 for compaction, a brake band 18 wound around a brake drum 12a of a lifting winch 12 and a brake when the pressure fluid is introduced. When the band 18 is loosened and the pressure liquid is not introduced, the brake cylinder 30 is adapted to apply tension to the brake band 18 by the built-in elastic body 32, and the conduit 36 for supplying the pressure liquid to the brake cylinder 30. And the solenoid 35a is not energized, the solenoid is switched to introduce pressure fluid into the brake cylinder 30.
When 35a is excited, the solenoid valve 35 is switched so that the pressure fluid introduction side in the brake cylinder 30 becomes atmospheric pressure.
And a wire rope 6 stretched between the hoisting winch 5 and the tip of the jib 4 or connected to a pendant cable 11 and a hook 15, or a hook 15 and a load suspended on the hook 15 for the wire rope 6 Alternatively, the load cell 10 for detecting the load acting on the pendant cable 11
And a moment limiter controller 41 that issues a command to turn on the relay 42 when the load detected by the load cell 10 corresponds to the weight of the hook 15 and the relay.
A normally open contact 38 that switches to the closed state so that the solenoid 35a of the solenoid valve 35 is energized and excited when 42 is turned on, and an automatic brake release switch 39 for returning the normally open contact 38 to the open state It consists of

[Operation] When performing the dynamic consolidation method, the automatic brake release switch 39 is open and the solenoid 35a of the solenoid valve 35 is not energized and excited, so that the solenoid valve 35 introduces pressure fluid into the brake cylinder 30. It is switching.
Therefore, the brake band 18 is loosened, and the lifting winch 12 is not braked. Therefore, by driving the lifting winch 12, the weight 16 hung from the hook 15 ascends together with the hook 15.

When the hook 15 and the weight 16 are raised to the upper limit position, the driving of the lifting winch 12 is stopped and the automatic brake release switch 39 is switched to the connected state. At this time, since the lifting winch 12 is not braked, if the driving of the lifting winch 12 is stopped, the weight 16 and the hook 15 fall freely, and the ground 16 is solidified by the impact of the weight 16.
When the weight 16 lands and the load cell 10 receives only the load corresponding to its own weight of the hook 15, the moment limiter controller 41 commands the relay 42 to turn on and be energized and excited. 38 is switched to be closed, and the solenoid 35a is energized and excited. Therefore, the solenoid valve 35 is switched so that the pressure liquid introduction side of the brake cylinder 30 communicates with the atmosphere, and the elastic band 32 pulls the brake band 18 to brake the lifting winch 12. Therefore, it is not necessary for the operator to rely on the intuition to brake the lifting winch 12 when the weight 16 is landed, and the dynamic consolidation method can be easily and reliably performed.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

1 and 2 show an embodiment of the present invention. FIG. 1 shows a schematic system of an automatic braking device, and FIG. 2 shows an outline of a mobile crane to which the automatic braking device is applied. There is.

In FIG. 2, 1 is a mobile crane, 2 is a revolving structure mounted on the traveling body 3 of the mobile crane 1 so as to be rotatable, 4 is a jib pivotally attached to the tip of the revolving structure 2 and 5 is a revolving structure. A hoisting winch installed on the body 2, 6 is a wire rope that is wound and unwound by the hoisting winch 5, and 7 is a frame 8
A sheave pivotally attached to the top of the wire rope to guide the wire rope 6, 9 is an equalizer sheave around which the wire rope 6 is wound, and 10 is an end portion of the wire rope 6 for measuring tension acting on the wire rope 6. A load cell installed between the tops of the frames 8, 11 a pendant cable that connects the equalizer sheave 9 and the tip of the jib 4, 12 is a lifting winch installed on the revolving unit 2, 13 is a winding winch 12, and is wound out The wire rope is guided downward by the sheave 14 from the end of the jib 4 and the hook 15 is hung up and down at the lower end, 16 is a weight that is detachably hung on the hook 15, and 17 is a weight 16 that is struck by the weight 16. It is a solidified ground.

The details of the automatic brake device will be described with reference to FIG. 1. A brake band 1 having brake shoes attached to a brake drum 12a fixed to a winch drum of a lifting winch 12.
Wrap 8 and attach one end of the brake band 18 to the bracket 1
9 and fix the other end of the brake band 18 to the bracket 20.
It is connected to one end of a link 21 which is pivotally attached so as to be pivotable up and down.

A link 24, which is rotated in the clockwise direction in FIG. 1 by depressing the brake pedal 22 and pulled back by the spring 23 when the foot is released from the brake pedal 22, returns to its original position, is pivotally attached to the bracket 25. A link 26 connected to the end of the link 24 opposite to the spring 23 is connected to one end of a link 28 pivotally attached to a bracket 27, and the other end of the link 28 and the end of the link 21 opposite to the anti-brake band 18 are connected by a link 29. Link.

The tip of the piston rod 30b of the brake cylinder 30 in which the casing 30a is pivotally attached to the bracket 31 is connected to the intermediate portion from the bracket 20 pivotal attachment portion of the link 21 to the link 29 connection portion, and the piston rod 30b side of the casing 30a is connected to the piston. The spring 32 is housed so that the rod 30b is biased in the backward direction, and the force of the spring 32 causes the link 21,
The lifting winch 12 can be braked via the brake band 18 and the brake drum 12a.

The hydraulic pump 33 is connected to the inlet port P of the solenoid valve 35 via the conduit 34, and the conduit 36 connected to the outlet port A of the solenoid valve 35 is connected to the brake cylinder 30 casing 30.
Connect to the head side oil chamber 30c of a.

The power source 37 is connected to the solenoid 35a of the solenoid valve 35, the normally open contact 38 and the brake release switch 39 are connected in series with the solenoid 35a, and the solenoid 35a and the normally open contact are provided on the downstream side of the current flow direction D of the power source 37. 38 In parallel with the circuit 40 to which the brake release switch 39 is connected,
A circuit 43 in which a moment limiter controller 41 and a relay 42 are sequentially connected in series is connected. The moment limiter controller 41 outputs a command to turn on the relay 42 when the load signal W from the load cell 10 becomes less than the weight of the hook 15 by itself, and when the load signal W exceeds the weight of the hook 15 by the relay 42. A command can be output to turn it off.

In the figure, 35b is a spring for switching the solenoid valve 35 so that pressure oil from the hydraulic pump 33 is introduced into the head side oil chamber 30c of the brake cylinder 30 when the solenoid 35a is not excited, 44 is a tank, and 45 is a tank. The relief valve, 46 is a pin fixed to the link 21, and 47 is a long hole provided at the tip of the piston rod 30b of the brake cylinder 30 so that the pin 46 can be fitted therein.

When performing a normal cargo handling work other than the dynamic consolidation method, the automatic brake release switch 39 is turned off. Therefore, for example, even if the load signal W detected by the load cell 10 becomes the weight of the hook 15 and the moment limiter controller 41 outputs an ON command to the relay 42 so that the relay 42 is energized and excited, the normally open contact 38 remains open. The solenoid valve 35 is still open, and therefore the solenoid valve 35 is switched to the port shown in FIG. 1, and the piston rod 30b of the brake cylinder 30 is projected by the oil discharged from the hydraulic pump 33, and the braking is released.

Thus, when braking the lifting winch 12 during normal cargo handling work, the operator depresses the brake pedal 22. Therefore, in FIG. 1, the link 24 overcomes the force of the spring 23 and rotates clockwise, the link 26 is pushed leftward, the link 28 rotates counterclockwise, and the link 29 rotates rightward. The link 21 is rotated counterclockwise to pull the brake band 18, and the lifting winch 12 is braked via the brake drum 12a. When the link 21 rotates counterclockwise, the pin 46 fixed to the link 21 slides against the long hole 47 at the tip of the piston rod 30b, so that the brake cylinder 30 receives no force from the link 21. .

When releasing the lifting winch 12 during normal cargo handling work, the operator releases his foot from the brake pedal 22. Then, in FIG. 1, the link 24 is pulled by the spring 23 to rotate counterclockwise, the link 26 is pulled to the right, the link 28 rotates clockwise, and the link 29.
Is pushed to the left and the link 21 is rotated clockwise, so that the brake band 18 is loosened and the lifting winch 12 is released from braking.

When carrying out the dynamic consolidation method, the lifting rope winch 5 is used to wind the wire rope 6 and the jib 4 is raised, and the lifting winch 12 is driven to depress or release the brake pedal 22 as appropriate. The hook 15 is lowered while adjusting the feeding speed of the wire rope 13 appropriately, and when the hook 15 is lowered to the lower end, the drive device is stopped and the brake pedal 22 is depressed to pull the brake band 18 to raise and lower it. Braking winch 12, hook
The weight 16 is hung on 15, the foot is released from the brake pedal 22, and the brake band 18 is loosened.
Take up and raise the weight 16.

Then, when the weight 16 is raised to the upper limit position, the automatic brake release switch 39 is switched to the connected state and the drive device of the lifting winch 12 is stopped. Then, since the lifting winch 12 is not braked, the lifting winch 12 reversely rotates due to the weight of the way 16 and the hook 15, the weight 16 freely falls with the hook 15, and the ground 17 is solidified by the impact of the weight 16. To be

Thus, when the weight 16 and the hook 15 are dropped, a load corresponding to the weight of the weight 16 and the hook 15 acts on the wire rope 6 that can be wound up and fed out by the hoisting winch 5, and the load cell 10 The load is detected. In this case, since the load detected by the load cell 10 is larger than the weight of the hook 15, the moment limiter controller 41 outputs an OFF command to the relay 42, and the normally-open contact 38 remains open.

When the weight 16 collides with the ground 17, a load corresponding to the dead weight of the hook 15 acts on the wire rope 6, and a load signal W corresponding to the dead weight of the hook 15 is given from the load cell 10 to the moment limiter controller 41, and the moment limiter controller 41. An on command is output from 41 to the relay 42.
Therefore, the current from the power supply 37 energizes the relay 42,
It is excited and the relay 42 closes the normally open contact 38.

When the normally open contact 38 is closed, current flows through the circuit 40, the solenoid 35a is energized and excited, and the solenoid valve 35 is connected to the conduit 3
6 and the tank 44 are switched so that they communicate with each other, and the inside of the pipeline 36 becomes atmospheric pressure. Therefore, the spring 32 causes the piston rod 30b to retract, and the piston rod 30b causes the pin 46 to move.
As a result of the link 21 being rotated counterclockwise in FIG. 1 via the, the brake band 18 is pulled and the brake drum 18 is pulled.
Since 12a is tightened by the brake band 18, the lifting winch 12 is braked.

As described above, when the way 16 lands and the load acting on the wire rope 6 due to the weight of the hook 15 is detected, the solenoid valve 35 is switched to move the lifting winch 12
Therefore, it is not necessary to rely on the operator's intuition to brake the lifting winch 12 in the case of operation by the dynamic consolidation method, and therefore the compaction work of the ground 17 by the dynamic consolidation method can be easily and reliably performed. It can be carried out.

Although the load cell 10 is attached between the end of the wire rope 6 and the frame 8 in the embodiment of the present invention, the load cell 10 is connected to the middle of the wire rope 6, the middle of the pendant cable 11, and the pendant cable 11. Of course, it can be attached between the jib 4 and the like, and other various changes can be made without departing from the scope of the present invention.

[Advantageous effects] According to the automatic braking device for a mobile crane of the present invention,
When solidifying the ground by the dynamic consolidation method, the weight lifting winch can be automatically braked without relying on the operator's intuition, so it is possible to perform the work easily and reliably. Can play.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, and FIG. 2 is an overall schematic view of a mobile crane to which the present invention is applied. In the figure, 1 is a mobile crane, 2 is a revolving structure, 3 is a traveling structure, 4
Is a jib, 5 is an undulating winch, 6 is a wire rope, 10 is a load cell, 11 is a pendant cable, 12 is a lifting winch, 12a is a brake drum, 15 is a hook, 16 is a weight, 17 is the ground, 18 is a brake band. , 30 is a brake cylinder, 32 is a spring (repellent body), 35 is a solenoid valve, 35a is a solenoid, 36 is a conduit, 38 is a normally open contact, 39
Is an automatic brake release switch, 41 is a moment limiter controller, and 42 is a relay.

Claims (1)

[Scope of utility model registration request] 1. A revolving structure 2 which is rotatably disposed on a traveling structure 3, a jib 4 which is rotatably supported by the revolving structure 2 and which can be raised and lowered by a hoisting winch 5. A weight 16 that is suspended from the tip of the jib 4 so that it can be hoisted and lowered by a winch 12 and that hardens the ground 17.
In a mobile crane 1 equipped with a hook 15 capable of suspending a vehicle, a brake drum 12a of a lifting winch 12 is provided.
When the pressure liquid is introduced, the brake band 18 is wound around and the brake band 18 is loosened, and when the pressure liquid is not introduced, the built-in elastic / repellent body 32 can apply tension to the brake band 18. If the solenoid 35a is connected to the brake cylinder 30 and the conduit 36 for supplying pressure fluid to the brake cylinder 30 and the solenoid 35a is not excited, the solenoid 35a is switched so that the pressure fluid can be introduced into the brake cylinder 30. Solenoid valve 35 that can be switched so that the pressure fluid introduction side in the brake cylinder 30 becomes atmospheric pressure
And a wire rope 6 stretched between the hoisting winch 5 and the tip of the jib 4 or connected to a pendant cable 11 and a hook 15, or a hook 15 and a load suspended on the hook 15 for the wire rope 6 Alternatively, the load cell 10 for detecting the load acting on the pendant cable 11
And a moment limiter controller 41 that issues a command to turn on the relay 42 when the load detected by the load cell 10 corresponds to the weight of the hook 15 and the relay.
A normally open contact 38 that switches to a closed state so that the solenoid 35a of the solenoid valve 35 is energized and excited when 42 is turned on, and an automatic brake release switch 39 for returning the normally open contact 38 to the open state An automatic braking device for a mobile crane characterized by the following features.