JP2555425Y2 - Hook storage device for self-propelled cranes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a self-propelled crane such as a truck crane, a rough terrain crane or a truck-mounted crane, and particularly relates to storage of hooks thereof.

(Prior art) In a self-propelled crane of this type, in order to prevent a hook suspended by a wire cable from swinging in a traveling state, a hook is attached to a tip of a boom prior to traveling of the self-propelled crane. It is necessary to perform localization (hereinafter referred to as storage).

On the other hand, in a crane that raises and lowers a hook with a winch composed of a wire cable and a winding drum,
If you take up too much wire cable during crane operation,
The hook may collide with the tip of the boom.

To prevent such a possibility, a winding detection switch is provided which is activated when the hook approaches the end of the boom by a predetermined value or more. By operating the winding detection switch, an alarm is issued and the winch hoisting force is reduced. (See Japanese Utility Model Unexamined Publication No. 2-57898). According to this structure, the hook is stored and damage due to a collision during crane operation is reduced.

(Problems to be solved by the invention) However, according to such a conventional technique, the hook can be stored, and at the same time, the damage due to the collision during the crane operation is reduced. It cannot be forcibly prevented.

This idea was made based on this background,
It is an object of the present invention to forcibly prevent a collision between a hook and a boom tip during a crane operation, and to easily store the hook in the boom tip.

(Means for solving the problem) In order to achieve this object, the invention according to claim 1
A winch composed of a wire cable and a take-up drum has a hook suspended from the tip of the boom so as to be able to move up and down, and a winding detection switch that operates when the hook approaches the tip of the boom by a predetermined value or more. A self-propelled crane having a winding stop circuit that stops driving of the winch by operating the winding detection switch, and a storage that inhibits operation of the winding stop circuit by operating the hook when the hook is stored. A hydraulic circuit for driving the winch with a hydraulic motor, and a hydraulic circuit for driving the hydraulic motor includes a relief valve for setting the hydraulic circuit in a low pressure state, and a flow control for limiting a flow rate of the hydraulic circuit. A self-propelled crane, characterized in that at least one of the valves is installed and this is operated in conjunction with the operation of the storage switch. Is a down hook storage devices.

(Operation) According to the invention of claim 1, since the worker does not operate the storage switch during the crane operation, when the wire rope is overwound, the winding stop circuit is activated. The winch winding operation is forcibly stopped, and the hook does not collide with the end of the boom.

Then, at the time of storing the hook, the worker can operate the storage switch to raise awareness of the storing operation of the hook, and the operation of the winding stop circuit is prohibited. And the hook is stored smoothly. In addition, at least one of the relief valve and the flow control valve is installed in the hydraulic circuit for the winch and linked with the operation of the storage switch, so that the hook is loosely stored and the tip of the hook or boom is damaged. The risk of being caused is reduced. Moreover, if the storage switch is forgotten to be turned off, the low-pressure relief valve or the flow control valve operates in conjunction with the storage switch, so that the hoisting force or hoisting speed of the hook is regulated as compared to normal work. Therefore, the operator can quickly detect that the storage switch has been forgotten to be turned off based on the winding state of the hook, and it is easy to prevent an operator's erroneous operation in which unintended hook storage is performed during normal work. .

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, an outline of the overall mechanical structure of the self-propelled crane will be described with reference to FIG. This will be described with reference to the drawings.

In FIG. 2, reference numeral 1 denotes a crane, which has a base 2, a swivel 3, a boom 4, and a hook 5.

The base 2 is fixedly formed on a vehicle body frame 6 of the automobile. A swivel 3 configured to be able to turn in the direction of arrow A in the figure is vertically erected on an upper surface of a central portion of the base 2. At the same time, a receiver 7 is installed therein, and a storage button 8 of the hook 5 is installed therein and connected to the receiver 7.

A control device 11, such as a valve, for controlling the operation of the crane 1 is provided on the upper surface of the base 2.

A boom 4 is connected to the upper end of the swivel 3 via a pivot.
The boom 4 is configured to be swingable in the direction of arrow B in the figure. A winding drum 14 for a wire cable 13 of a winch 12 for driving a hook 5 to be described later is installed inside the swivel 3.

The boom 4 is composed of an outer cylinder 4a pivotally supported at the upper end of the swivel base 3 and an inner cylinder 4b housed telescopically therein, and is configured to be extendable and contractible in the direction of arrow C in the figure.

A guide pulley 15 that guides a wire cable 13 extending from the winding drum 14 and a winding detection switch 16 that detects excessive winding of the wire cable 13 are installed at the tip of the inner cylinder 4b of the boom 4. ing.

The distal end 13a of the wire cable 13 is fixed to a lower portion of the distal end of the inner cylinder 4b.
Cable 1 separated from the tip 13a of the
3, a weight 17 is fixed at the upper position.
At a lower position, the hook 5 is suspended via a pulley 18 installed therein.

Therefore, by changing the winding amount of the wire cable 13 by the winding drum 14, the hook 5 can be driven to move up and down as indicated by arrow D in the figure.

A rope 19 is stretched between the weight 17 and the winding detection switch 16.

The rope 19 is connected to an operating arm (not shown) of the winding detection switch 16, and in the normal case as shown, the winding detection switch 16 is in an off state, and when the weight 17 is lifted, The winding detection switch 16 is turned on when the operating arm is displaced. When the winding detection switch 16 is turned on, an alarm buzzer sounds by an electric circuit (not shown).

In FIG. 2, reference numeral 9 denotes a transmitter. In this embodiment, a storage button 8 of the hook 5 is also provided in the transmitter 9, and the same operation as the storage button 8 is performed by radio. In some cases, the remote control device may be configured as a wired remote control device, or the installation of the remote control device may be omitted, and only the storage button 8 installed on the base 2 may be used.

By the way, the crane 1 is driven by a driving device 21 described below with reference to FIG.

That is, the driving device 21 is of an electro-hydraulic type, and includes a hydraulic pump 22 as a power source, a turning hydraulic motor 23 for rotating and driving the swivel 3, and a raising and lowering hydraulic cylinder for driving the boom 4 up and down. 24 and the inner cylinder 4b of the boom 4
A hydraulic cylinder 25 for extending and contracting the outer cylinder 4a and a hydraulic motor 26 for raising and lowering the winding drum 14 of the winch 12 for raising and lowering the hook 5 are provided.

In the oil passage 27 extending from the discharge port of the hydraulic pump 22, a 6-port three-position switching valve 28, which is similarly configured, is provided.
23, an up / down hydraulic cylinder 24, a telescopic hydraulic cylinder 25, and a lifting / lowering hydraulic motor 26 are connected respectively.

A drain passage branched from the oil passage 27 at a position on the discharge port side of the hydraulic pump 22 with respect to these switching valves 28.
The main relief valve 32 is mounted in the drain passage 31.

The main relief valve 32 is a balanced piston type relief valve having a pilot passage 33, and a normally closed solenoid on-off valve 35 is interposed on the drain 34 side of the pilot passage 33.

Therefore, the main relief valve 32 is
When the discharge pressure exceeds a set value and when the solenoid on-off valve 35 connects the pilot passage 33 to the drain 34, the drain passage 31 is connected to the drain 34 to reduce the oil pressure in the oil passage 27 to an extremely low pressure. In this embodiment, a winding stop operation described later is performed.

In the neutral position 36, each of the switching valves 28 communicates the pressure oil from the oil passage 27 to the drain 34 through the corresponding valve, and the respective hydraulic circuits passing through the turning hydraulic motor 23 and the like are closed. ing.

In addition, at the first offset position 37 of each switching valve 28, the hydraulic oil from the oil passage 27 is introduced into each hydraulic circuit to cause the turning hydraulic motor 23 and the like to perform required operations. The oil passage for returning the return oil to the drain 34 due to the operation of the turning hydraulic motor 23 and the like is opened.

Further, at the second offset position 38 of each switching valve 28, in the opposite direction to the case of the first offset position 37,
Pressure oil is introduced into each hydraulic circuit, and the turning hydraulic motor 23 and the like are driven in the opposite direction.

Therefore, in this crane 1, each switching valve 28
Is normally connected to the oil passage 27 at a neutral position 36, and when each part needs to be operated, one of the switching valves 28 is selectively connected to the first offset position 37 or the first offset position 37. The position is switched to the second offset position 38 to perform a required operation.

In addition, the oil passage 27 in this embodiment and the lifting oil passage 41 branched from the oil passage 27 to the lifting hydraulic motor 26 are
Switching valve 28a (hereinafter, suffix a for distinction from other switching valves)
) To compose a hydraulic circuit for elevating.

Further, a low-pressure relief valve 42 and a flow control valve 43 are provided in the lifting oil passage 41 of the lifting hydraulic motor 26 of this embodiment, and at the first offset position 37, the lifting hydraulic The motor 26 drives the hook 5 upward, and at the second offset position 38, the lifting hydraulic drive motor 26 drives the hook 5 downward.

The low-pressure relief valve 42 is a balance piston-type relief valve installed on a drain passage 47 formed by branching from the lifting oil passage 41, a check valve 44, and a pilot passage 45.
A normally closed solenoid on-off valve 46 is provided on the drain 34 side of the pilot passage 45.

Therefore, when the solenoid on-off valve 46 connects the pilot passage 45 to the drain 34, the low-pressure relief valve 42 connects the drain passage 47 to the drain 34,
This is to reduce the oil pressure in 41 to a low pressure state.

This low pressure relief valve is the same as the main relief valve.
It may be installed in the oil passage 27 in parallel with 32.

The flow control valve 43 is composed of a solenoid-operated switching valve, and in a normal position 48, the pressure oil supplied to the lifting oil passage 41 can flow as it is without any substantial resistance, but when the solenoid operates. When switching to the offset position 49, the flow rate of the pressure oil is limited under a certain restriction.

Further, as such a flow control valve, a switching valve 28a for branching an elevating oil passage 41 from the oil passage 27 to the elevating hydraulic motor 26 is constituted by an electromagnetic proportional control valve. The control may be performed by controlling the state of a half spool.

The solenoid on-off valves 35, 4 in such a hydraulic system
6 and the flow control valve 43 are controlled by the following electric circuit 51.

The electric circuit 51 includes a power supply 52, a winding detection switch 16, and a storage switch 53 that is closed by operating the storage button 8.

The storage switch 53 is configured to close the contact only when the storage button 8 is pressed. This is because it is preferable in terms of work safety to make the worker clearly aware that the hook 5 is being stored.

The electric circuit 51 includes the solenoid on-off valve.
The first relay 54 and the contacts 55 and 56, and the second relay 57 and the contacts 58 and 59 are provided to control the energization to 35 and the like.

 The contents of control by the electric circuit 51 are as follows.

First, a description will be given of a case where the hook 5 is moved up and down by a normal crane operation by the crane 1 of this embodiment.
Since 53 is off and the first relay 54 is not energized, the open contact 55 of the first relay 54 remains off and the close contact 56 remains on.

Therefore, the circuit from the power source 52 to the solenoid switching valve 46 is open, and as a result, the low pressure relief valve 42 is inoperable.

A second relay 57 is provided in a circuit from the power supply 52 to the solenoid switching valve 35 and a circuit from the power supply 52 to the flow control valve 43.
Since the open contacts 58 and 59 of the second relay 5
The energization to the solenoid 7, that is, the energization to the solenoid switching valve 35 and the like is controlled by turning on / off the winding detection switch 16.

Therefore, during this crane operation, when the wire cable 13a is wound up too much and the winding detection switch 16 is turned on, the second relay 57 is energized and each open contact 5
8, 59 are turned on, and the solenoid on-off valve 35 and the flow control valve 43 of the main relief valve 32 operate simultaneously.

By the operation of the solenoid on-off valve 35, the pilot passage 33 opens, and the drain passage 31 communicates with the drain 34.
The pressurized oil discharged from the hydraulic pump 22 is substantially lifted and lowered by an oil passage 41.
The lifting hydraulic motor 26 stops and the hook 5
Is stopped and the winding is stopped.

As a result, it is possible to reliably prevent the hook 5 from colliding with the tip of the boom 4 due to the carelessness of the operator during the crane operation.

 Next, the operation in the case of storing the hook 5 will be described.

When storing the hook 5, the operator presses the storage button 8 of the transmitter 9, for example.

Thereby, the storage switch 53 is passed through the receiver 7 of the base 2.
Is closed and a voice circuit (not shown) says "Please move the boom to the running position. Store the hook."
A voice alert is issued.

When the boom 4 is not in the running posture, if the operator stops pressing the storage button 8, the storage switch 8 is turned off and the state returns to a normal crane operation state. By operating the switching valve 28, the boom 4 can be brought into a predetermined running posture.

Then, the storage switch by pressing the storage button 8
When the switch 53 is turned on, the first relay 54 is energized, the open contact 55 is closed, and the close contact 56 is opened.

As a result, the main relief valve 32 is brought into an inoperative state, and a normal hoisting operation or the like in the winch 12 is prohibited, and an operation of stopping the winding is prohibited.

That is, in this embodiment, the winding stop circuit M including the power supply 52 and the solenoid on-off valve 35
By turning on 53, the closing contact 56 is turned off and the operation of the winding stop circuit M is prohibited.

Therefore, when the hook 5 is stored,
Does not stop at the winding position as in the crane operation.

At the same time, the low pressure relief valve 42 is activated by the solenoid switching valve 46 of the low pressure relief valve 42 connecting the pilot passage 45 to the communicating state.

Therefore, in the storing operation of the hook 5, the pressure oil in the lifting oil passage 41 drives the lifting hydraulic motor 26 at a low pressure set by the low-pressure relief valve 42.

When the storage switch 53 is turned on and the switching valve 28a of the lifting oil passage 41 to the lifting hydraulic motor 26 is switched to the first offset position 37 by a solenoid or the like, only the storage button 8 is pressed. The operation of storing the hook 5 can be performed by the operation.

At this time, if operations such as extension of the boom 4 and winding of the winch 12 are locked when the storage switch 53 is turned on, the safety of the storage operation is further improved.

When the hook 5 reaches a position higher than the winding position, the winding detection switch 16 is turned on, and the flow control valve 43 is switched to the offset position having the throttle as described above, but as in the crane operation. The hook 5 does not stop at the winding position, and the hook 5 is slowly stored at the tip of the boom 4. Therefore, the hook 5 and the tip of the boom 4 are not damaged when the hook 5 is retracted.

As described above, in the crane 1 of this embodiment,
When the storage button 8 is provided, and when the storage button 8 is not pressed, the lifting of the hook 5 is stopped when the wire cable 13 is overwound, and when the storage button 8 is pressed, the hook Since the stop of winding of the hook 5 is prohibited and the hook 5 is slowly lifted, the handling of the self-propelled crane becomes easy.

In the embodiment described above, the low pressure relief valve 42 is operated instead of the main relief valve 23 by pressing the storage button 8, and the flow control valve 43 is operated by operating the winding detection switch 16. However, in the present invention, this is reversed, and the flow control valve may be operated by pressing the storage button 8, and the low pressure relief valve 42 may be operated instead of the main relief valve 32 by operating the winding detection switch 16. .

In addition, the present invention provides the same low pressure relief valve 42 or flow control valve 43 as described above in the lifting oil passage 41 or the oil passage 27.
Only one of them may be installed and operated by pressing the storage switch 8.

That is, in these modified examples, the storage button 8
Pressing the button prohibits the winding stop operation.
Press operation to activate at least one of the low pressure relief valve and the flow control valve, thereby preventing the hook from colliding with the boom tip during crane operation and smoothly storing the hook at the boom tip. .

Then, the storage switch 53 used in the above embodiment is used.
Is the storage switch 53 only when the storage button 8 is pressed.
However, the present invention is not limited to this. For example, the present invention can be implemented even when the storage button 8 is alternately turned on or off each time the storage button 8 is pressed. It can also be implemented using a switch.

When a storage switch is configured using a simple switch, it is preferable to separately install a storage release switch to improve the operability of the switch. If the contact of the storage switch 53 is not configured to close only when the storage button 8 is pressed, the operator turns off the storage switch so as to open the contact of the storage switch 53 after the hook 5 is stored. If the user forgets to turn off the storage switch, an erroneous operation occurs in which unintended hook storage is performed in a normal operation thereafter.

However, according to the present invention, when the storage switch is forgotten to be turned off, the low-pressure relief valve or the flow control valve is operated in conjunction with the storage switch, so that the hoisting force or hoisting speed of the hook is reduced to a normal operation. The operator is able to quickly detect that the storage switch has been forgotten to be turned off based on the winding status of the hooks, and the operator is prevented from erroneous operation that unintended hook storage is performed during normal work. It is easy to prevent.

(Effects of the Invention) As described above, according to the invention of claim 1,
Since the worker does not operate the retract switch during crane operation, if the wire rope is overwound, the winding stop circuit is activated and the winch winding operation is forcibly stopped, and the hook is stopped. Will not hit the boom tip.

At the time of storing the hook, the worker can operate the storage switch to raise awareness of the storing operation of the hook, and the work of the winding stop circuit is prohibited. And the hook is stored smoothly. In addition, at least one of the relief valve and the flow control valve is installed in the hydraulic circuit for the winch and linked with the operation of the storage switch, so that the hook is loosely stored and the tip of the hook or boom is damaged. The risk of being caused is reduced. In addition, when the storage switch is forgotten to be turned off, the low-pressure relief valve or the flow control valve operates in conjunction with the storage switch, so that the hoisting force or hoisting speed of the hook is regulated as compared with normal work. Therefore, the operator can quickly detect that the storage switch has been forgotten to be turned off based on the winding state of the hook, and it is easy to prevent an operator's erroneous operation in which unintended hook storage is performed during normal work. .

[Brief description of the drawings]

The drawings relate to an embodiment of the present invention. FIG. 1 is a circuit diagram of a driving device, and FIG. 2 is a schematic explanatory view of a self-propelled crane. M; winding stop circuit, 1; crane, 4; boom, 5; hook, 1
2; winch, 13; wire cable, 14; winding drum,
16; winding detection switch, 26; hydraulic motor (for lifting), 41;
Elevating oil passage, 42; Low pressure relief valve, 43; Flow control valve, 53;
Storage switch.

Claims (2)

(57) [Scope of request for utility model registration] 1. A hook which is suspended by a winch constituted by a wire cable and a take-up drum so as to be able to ascend and descend from a tip of a boom, and operates when the hook approaches the tip of the boom by a predetermined value or more. A self-propelled crane having a winding detection switch, comprising: a winding stop circuit for stopping driving of the winch by operation of the winding detection switch; A storage switch for prohibiting the operation, wherein the winch is driven by a hydraulic motor, and a hydraulic circuit for driving the hydraulic motor includes a relief valve for setting the hydraulic circuit in a low pressure state, and a flow rate of the hydraulic circuit. At least one of the flow control valves for limiting the pressure is installed, and this is operated in conjunction with the operation of the storage switch. Hook storage device for self-propelled cranes. 2. A hook which is suspended by a winch composed of a wire cable and a winding drum so as to be able to ascend and descend from a tip of the boom, and is activated when the hook approaches the tip of the boom by a predetermined value or more. A self-propelled crane having a winding detection switch, comprising: a winding stop circuit for stopping driving of the winch by operation of the winding detection switch; A storage switch for prohibiting operation, wherein the winch is driven by a hydraulic motor, and a hydraulic circuit for driving the hydraulic motor includes a relief valve for setting the hydraulic circuit in a low pressure state, and a flow rate of the hydraulic circuit. And a flow control valve for restricting the operation, one of which is operated in conjunction with the operation of the storage switch, and the other is operated by the winding detection switch. A hook storage device for a self-propelled crane, wherein the hook storage device is operated in conjunction with the operation of the latch.