JP3115835B2 - Crane overwind prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane overwind prevention device that detects overwinding of a tower boom, jib boom or crane boom and automatically stops the boom hoisting operation.

[0002]

2. Description of the Related Art Raising and lowering operations of a crane boom mounted on a crane body, a tower boom of a tower crane, or a tower jib mounted on the tip of a tower boom are performed by using a hoisting rope mounted on the boom or the tip of the jib on a hoisting drum. This is done by winding or unwinding. If the hoisting rope is wound up too much when raising or lowering the boom, the boom or jib will exceed the angle suitable for the work, so the crane or tower crane will try to exceed the predetermined angle with the boom etc. In this case, there is provided an overwinding prevention device that automatically stops winding of the undulating rope.

[0003]

However, in the state where the overwinding prevention device is operated and the winding of the hoisting rope is stopped, the angle of the boom or the jib exceeds the angle suitable for the work, so that the work is not performed. In order to return, the operation of releasing the over-wound state by the operator is indispensable, and there is a problem that operability is poor.

[0004] It is an object of the present invention to provide an overwinding prevention device for a crane that can avoid an overwinding state of the hoisting rope after the operation of the overwinding prevention device.

[0005]

FIG. 1 shows an embodiment of the present invention.
Referring to FIG. 2 and FIG.
An elevating means comprising at least one elevating member 5 which is moved up and down by the elevating means 9, and a corner which is not suitable for the operation of the elevating member 5.
And an overwinding state releasing means 32 for driving the undulating means in a direction for detecting the overwinding state which is a degree state and for releasing the overwinding state, and stopping at an angle state enabling work . This achieves the above object.

According to the second aspect of the present invention, the tower 2 which is raised and lowered by the first raising and lowering means 4, the jib 5 which is raised and lowered by the second raising and lowering means 9, and the angle state which is not suitable for the work of the jib 5 are provided.
The over-winding state releasing means 32 for driving the second undulating means 9 in a direction for detecting the over-winding state and releasing the over-winding state, and stopping at an angle allowing the work. To achieve.

According to the third aspect of the present invention, the tower 2 which is raised and lowered by the first raising and lowering means 4, the jib 5 which is raised and lowered by the second raising and lowering means 9, and the jig 5 which is not suitable for the work of the tower 2.
The above-mentioned object is achieved by providing overwinding state releasing means 32 for detecting a certain overwinding state and driving and stopping the first undulating means 4 in a direction for releasing the overwinding state in an angle state enabling work. To achieve.

According to a fourth aspect of the present invention, there is provided a crane boom which is raised and lowered by a raising and lowering means, and which is suitable for the operation of the crane boom.
Angular state that enables the work by driving the undulating means in the direction to detect the over-wound state that is a large angle state and release the over-wound state
The above-mentioned object is achieved by providing the overwinding state releasing means 32 which stops by the above.

The invention according to claim 5 further comprises a hook elevating means 12 for elevating and lowering the hook 10, and the overwinding state releasing means 3 is provided.
2 detects the overwinding state, which is an angle state unsuitable for the operation of the jib 5, and drives the hook lifting / lowering means 12 in a direction to release the overwinding state, and stops at a position enabling the operation. />

In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used for easy understanding of the present invention. However, the present invention is not limited to this.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. -First Embodiment- A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of a tower crane according to a first embodiment of the present invention. As shown in FIG. 1, a tower crane according to a first embodiment includes a crane main body 1 having a lower traveling body and an upper revolving superstructure, and a tower boom (hereinafter referred to as a tower boom) connected to the crane main body 1 so as to be able to move up and down. 2), a boom hoisting drum 4 that winds or unwinds a boom hoisting rope 3 connected via a pendant rope 3a attached to the upper end of the tower 2 to raise and lower the tower 2 and an upper end of the tower 2 And a tower jib (hereinafter, referred to as a jib) 5 which is connected to the upper part so as to be freely raised. A swing lever 7 is provided at the upper end of the tower 2. The swing lever 7 is schematically constituted by combining three members in a triangular shape, one of three vertices is rotatably connected to the upper end of the tower 2, and the other two vertices are connected to the jib pendant ropes 6a and 8 respectively. Are linked. The upper end of the jib pendant rope 8 is connected to the upper end of the jib 5. The other end of the pendant rope 6a is connected to the jib hoisting rope 6, and the jib hoisting auxiliary drum 9 winds and unwinds the jib hoisting rope 6 to raise and lower the tower jib 5. The lifting and lowering of the hook 10 is performed by winding and unwinding the hoisting rope 11 by the hoisting main winding drum 12.

FIG. 2 is a diagram showing a hydraulic circuit for driving the auxiliary hoist drum 9 for raising and lowering the jib. As shown in FIG. 2, the hydraulic circuit for driving the auxiliary winding drum 9 is connected to an output shaft (not shown) of the engine of the crane, and is driven by the main pump 21A and the pilot pump 22A driven by the engine. The auxiliary motor 23 which rotates by the supplied pressure oil, and the auxiliary motor 2
A control valve 24 for switching the pressure oil to the control valve 24; an operation lever 25 for controlling the pressure of the pressure oil supplied from the pilot pump 22A to the pilot chambers 24a and 24b of the control valve 24 to switch the control valve 24; The pilot pressure according to the operation amount of the operation lever 25 is applied to the pilot chamber 24 of the control valve 24.
a, pilot valves 25a, 25b to be supplied to
From the pilot valves 25a, 25b to the pilot chamber 24a,
24b, a pilot valve 25
a, a first switching valve 26 for switching the flow of the pressure oil from the pilot valve 25b, and a first proportional valve provided in a pipeline from the pilot valve 25b to the pilot chamber 24b for further adjusting the pilot pressure from the pilot valve 25b. A pressure reducing valve 27;
The pressure sensor 20A detects the pressure of the pressure oil supplied from the control valve 24 to the auxiliary motor 23.
The pressure detection signal of the pressure sensor 20A is input to the controller 32, and the first switching valve 26 and the first proportional pressure reducing valve 2
7, the drive of which is controlled by the controller 32 as will be described later. The first switching valve 26 is at the position b when a main power switch (not shown) is turned on, and the first proportional control valve 27 is at the fully open position b. The position can be switched.

The main pump 21A is a variable displacement hydraulic pump. The amount of pressure oil discharged is changed by changing the tilt angle of the main pump 21A by a regulator (not shown). The jib 5 is provided with an angle detector 30 for outputting an angle signal corresponding to the jib angle θ1, and a micro switch 31 for detecting that the jib angle θ1 has reached a predetermined angle is associated with the jib 5. It is provided.
The tower 2 is provided with an angle detector 34 that outputs an angle signal corresponding to the tower angle θ2. Here, the jib angle θ1 and the tower angle θ2 are tower 2
Means the angle between the center line and the horizontal ground plane.
The angle detector 30, the micro switch 31, and the angle detector 34 are connected to the controller 32. Note that the rotation of the auxiliary winding motor 23 is transmitted through the reduction winding 39 to the auxiliary winding drum 9.
Is transmitted to

To raise the jib 5, the operating lever 25 is operated upward. When the operating lever 25 is operated, the pilot 32 passes through the first proportional pressure reducing valve 27 which has been previously switched to the fully open position b by the controller 32 and the first switching valve 26 which has been switched to the b position. The pressure oil of the pressure adjusted by the valve 25b is supplied to the pilot chamber 24b of the control valve 24,
The control valve 24 is switched to the position b. Thereby, the pressure oil from the main pump 21A is supplied to the auxiliary winding motor 23 via the control valve 24, and the auxiliary winding drum 9 rotates in the direction of winding the undulating rope 6. on the other hand,
To lower the jib 5, the operation lever 25 is operated downward. When the operating lever 25 is operated, the pilot valve 2 passes through the first switching valve 26 switched to the position b.
The pressure oil of the pressure adjusted by 5a is supplied to the pilot chamber 24a of the control valve 24, and the control valve 24 is switched to the position a. Then, pressure oil from the main pump 21A is supplied to the auxiliary winding motor 23 via the control valve 24, and the auxiliary winding drum 9 rotates in a direction in which the hoisting rope 6 is extended.

FIG. 3 is a diagram showing a hydraulic circuit for driving the tower hoisting drum 4. In FIG. 3, the same reference numerals as those shown in FIG. 2 are used also as the hydraulic circuit for raising and lowering the jib, and those having different reference numerals are used for the hydraulic circuit for raising and lowering the tower. As shown in FIG. 3, a hydraulic circuit for driving the undulating drum 4 includes a regulator (not shown).
Motor 43 that is rotated by pressure oil supplied from a main pump 21B whose tilt angle is controlled by a control valve 44 that switches pressure oil from the main pump 21B to the undulation motor 43, and a control valve 44 that switches from a pilot pump 22A to a control valve 44. Control the pressure of the pressure oil supplied to the pilot chambers 44a and 44b of the
Lever 45 for switching the operation lever and a pilot pressure corresponding to the operation of the operation lever 45
And pilot pipes 45a and 45b for supplying the pilot chambers 44a and 44b to the pilot chambers 44a and 44b, and pipes extending from the pilot valves 45a and 45b to the pilot chambers 44a and 44b.
A second switching valve 46 for switching the flow of the pressure oil from the pilot valves 45a and 45b, and a second switching valve 46 provided in a pipeline from the pilot valve 45b to the pilot chamber 44b for further adjusting the pilot pressure from the pilot valve 45b. And a pressure sensor 2 for detecting the pressure of pressure oil supplied from the control valve 44 to the undulation motor 43.
0B. The pressure detection signal of the pressure sensor 20B is input to the controller 32, and the driving of the second switching valve 46 and the second proportional control valve 47 is controlled by the controller 32 as described later. 46
As in the case of the first switching valve 26, the main power switch is turned on to switch to the position b, and the second proportional control valve 47 is switched to the fully open position b as in the case of the first proportional pressure reducing valve 27. . The rotation of the undulating motor 43 is controlled by the speed reducer 4.
9 to the undulating drum 4.

To raise the tower 2, the operation lever 45 is operated upward. When the operating lever 45 is operated, the pilot 32 passes through the second proportional pressure reducing valve 47 which has been previously switched to the fully open position b by the controller 32 and the second switching valve 46 which has been switched to the b position. The pressure oil of the pressure adjusted by the valve 45b is supplied to the pilot chamber 44b of the control valve 44,
The control valve 44 is switched to the position b. Thereby, the pressure oil from the main pump 21B is supplied to the undulating motor 43 via the control valve 44, and the undulating drum 4 rotates in the direction of winding the undulating rope 3. On the other hand, to lower the tower 2, the operation lever 45 is operated downward. When the operating lever 45 is operated, the pressure oil adjusted by the pilot valve 45a is supplied to the pilot chamber 44a of the control valve 44 through the second switching valve 46 switched to the position b. The control valve 44 is switched to the position a. Thus, the pressure oil from the main pump 21B is supplied to the up / down motor 43 via the control valve 44, and the up / down drum 4 rotates in the direction in which the up / down rope 3 is fed.

FIG. 4 is a diagram showing a hydraulic circuit for driving the main winding drum 12. In FIG. 4, the same components as those shown in FIG. 2 are used also as the hydraulic circuit for raising and lowering the jib, and those having different symbols are used for the hydraulic circuit for the main winding drum. As shown in FIG. 4, the hydraulic circuit that drives the main winding drum 12 switches between a main winding motor 53 that rotates by pressure oil supplied from the main pump 21A and pressure oil from the main pump 21A to the main winding motor 53. The control valve 54 and the pilot pump 22
From the pilot chambers 54a, 54 of the control valve 54
An operation lever 55 for controlling the pressure of the pressure oil supplied to the control valve 4b to switch the control valve 54, and a pilot for supplying a pilot pressure corresponding to the operation of the operation lever 55 to the pilot chambers 54a and 54b of the control valve 54. Valves 55a, 55b and pilot valves 55a, 5
A third switching valve 56 that is provided in a pipeline from the pilot valve 5b to the pilot chambers 54a and 54b to switch the flow of pressure oil from the pilot valves 55a and 55b;
b to the pilot chamber 54b,
It comprises a third proportional pressure reducing valve 57 for further adjusting the pilot pressure from the pilot valve 55b, and a pressure sensor 20C for detecting the pressure of the pressure oil supplied from the control valve 54 to the main winding motor 53. The pressure detection signal of the pressure sensor 20C is input to the controller 32, and the third switching valve 5
The driving of the sixth and third proportional control valves 57 is controlled by the controller 32 as described later, but the third switching valve 56 is not shown similarly to the first and second switching valves 26 and 46. When the main power switch is turned on,
The third proportional pressure reducing valve 57 can be switched to the fully open position b, similarly to the first and second proportional pressure reducing valves 27 and 47. The rotation of the main winding motor 53 is transmitted to the main winding drum 12 via a speed reducer 59.

In order to raise the hook 10, the operation lever 55 is operated upward. When the operating lever 55 is operated, the third proportional pressure reducing valves 57 and b, which have been previously switched to the fully open position b by the controller 32,
Through a third switching valve 56 which has been switched to a position,
Pressure oil of the pressure adjusted by the pilot valve 55b is supplied to the pilot chamber 54b of the control valve 54, and the control valve 54 is switched to the position b. As a result, the pressure oil from the main pump 21A is supplied to the main winding motor 53 via the control valve 54, and the main winding drum 12 rotates in the direction of winding the hoisting rope 11. On the other hand, in order to lower the hook 10, the operation lever 55 is operated downward. When the operation lever 55 is operated, the pressure oil adjusted by the pilot valve 55a is supplied to the pilot chamber 54a of the control valve 54 through the third switching valve 56 switched to the position b. The control valve 54 is switched to the position a. Thereby, the pressure oil from the main pump 21A is supplied to the main winding motor 53 via the control valve 54,
The main winding drum 12 rotates in a direction in which the hoisting rope 11 is paid out.

Next, the operation of the present embodiment will be described. FIG. 5 is a flowchart for explaining the processing performed in the controller 32 when the jib 5 stands. In the present embodiment, the jib relative angle θ1
R is represented by (tower angle θ2−jib angle θ1), and a position where the jib relative angle θ1R becomes 15 ° is defined as an overwinding position.
First, the operation lever 25 is operated upward to take up the undulating rope 6 and perform the operation of raising the jib 5. Then, in step S1, it is determined whether or not the jib 5 is wound, and the process of step S1 is repeated until step S1 is affirmed. In step S2, the angle detector 3
Based on the signals from 0 and 34, it is determined whether or not the jib relative angle θ1R has become 15 °, that is, whether or not the jib 5 has become overwound. If step S2 is denied, the process ends if it is determined in step S3 that the hoisting operation of the jib 5 has been stopped. If step S3 is denied, the process returns to step S2 to continue the jib hoisting.

If step S2 is affirmative, step S
At 4, the first proportional pressure reducing valve 27 is switched from position b to position a. As a result, even if the operation lever 25 is operated, the pressure oil supplied from the pilot valve 25b to the pilot chamber 24b of the control valve 24 is shut off, so that the driving of the auxiliary winding motor 23 is stopped. Is also stopped. Then, in step S5, the pressure sensor 2 determines whether the jib 5 has stopped.
Judgment is made based on the pressure detection signal from 0A, and if not stopped, the processing of step S4 and step S5 is repeated again. When step S5 is affirmed, in step S6, the first switching valve 26 is switched from the position b to the position a, and the first proportional pressure reducing valve 27 is switched from the position a to the position b. As a result, the pressure oil supplied from the pilot valve 25b to the pilot chamber 24b of the control valve 24 reverses the rotation when the first switching valve 26 is at the position b, so that the operation lever 25 is operated upward. Also, the pressure oil from the pilot valve 25b is supplied to the pilot chamber 24a, and the auxiliary motor 23 rotates in the direction in which the hoisting rope 6 is extended. Accordingly, the jib 5 starts to lower, whereby the jib 5 is released from the over-wound state and automatically returns to the safe side.

Then, in step S7, it is determined whether or not a predetermined time t has elapsed after step S6, and if it has elapsed, in step S8 the first proportional pressure reducing valve 2 is determined.
7 is switched to the position a again. Thus, even if the operation lever 25 is operated, the pressure oil supplied from the pilot valve 25b to the pilot chamber 24a is shut off, so that the driving of the auxiliary winding motor 23 is stopped. Stop and end the process.

When the lowering operation of the tower 2 and / or the raising operation of the hook 10 are performed during the standing operation of the jib 5, the tower angle θ2 and the hook 10 input from the angle detector 34 to the controller 32 are provided. The controller 32 controls the second and third proportional pressure reducing valves 4 according to the winding amount of
7, 57 are switched from the position b to the position a, the pilot pressure is shut off, the lowering operation of the tower 2 and the winding of the hook 10 are stopped, and the second and third switching valves 46,
By switching 56 to the a position and switching the second and third proportional pressure reducing valves 47 and 57 to the b position again, the tower 2 is raised and the hook 10 is extended.

Here, the reason why the lowering operation of the tower 2 is stopped is that when the tower 2 performs the lowering operation and the jib 5 performs the upright operation, the degree of the jib relative angle θ1R becomes smaller and the overwinding state occurs. Is further promoted. The lifting operation of the hook 10 is stopped because the jib 5 may be erected by the hook 10 that is raised by the hoisting rope 11 even when the jib hoisting motor 23 is stopped.

As described above, in the present embodiment, the jib 5 is stopped when the overwinding state (θ1R = 15 °) is detected and the lowering operation is performed. Can be automatically returned to the safe side, whereby the work can be performed safely. Further, since the lowering operation of the tower 2 and the raising / lowering operation of the hook 10 are also reversed, the overwinding state of the jib 5 is promoted, and the hook 10 is hooked on the tip of the jib 5 so that the jib 5 is caught.
Does not stand up any longer, so that the work can be performed more stably. Also, since the jib angle is detected by the two systems of the angle detector 30 and the micro switch 31, the jib angle is reliably detected,
The stop processing of the jib 5 can be executed reliably.

Since the overwinding state occurs even during the standing operation of the tower 2 alone, similar to the case of the jib 5,
It is also possible to control the driving of the undulating motor 43. For example, when the overwinding state of the tower 2 is θ2 = 88 °,
The normal rising operation is performed until the tower angle θ2 becomes 88 °, and when the overwinding state occurs, the second proportional pressure reducing valve 47
Is switched from the position b to the position a, and the standing operation of the tower 2 is stopped. Then, after confirming the stop of the standing operation of the tower 2 by the pressure detection signal from the pressure sensor 20B, the second
Is switched to the position a and the second proportional pressure reducing valve 47 is switched to the position b, and the auxiliary motor 43 is rotated in the direction in which the hoisting rope 3 is fed out to lower the tower 2 for a predetermined time t. After the lapse of time, the second proportional pressure reducing valve 47 is switched to the position a again to stop the lowering operation of the tower 2, and the process ends.

Thus, even if the tower 2 is overwound, the tower 2 is automatically returned to the safe side, so that the work can be performed safely.

If the hook 10 is caught on the tip of the jib 5 during the winding operation of the hook 10 alone, the jib 5 is erected, so that the driving of the up / down motor 53 is controlled as in the case of the jib 5 described above. It is also possible. For example, when the winding is continued while the hook 10 is hooked on the tip of the jib 5 and the relative angle θ1R of the jib 5 becomes 15 ° or less, the third proportional pressure reducing valve 57 is moved from the position b to the position a at that time. The operation is switched to stop the winding operation of the hook 10. Then, after confirming the stop of the winding operation of the hook 10 by the pressure sensor 20C, the third switching valve 56 is switched to the position a and the third proportional pressure reducing valve 57 is switched to the position b, and the main winding motor 53 is wound. By rotating the upper rope 11 in the extending direction, the lowering operation of the hook 10 is performed, and after the elapse of a predetermined time t, the third proportional pressure reducing valve 57 is switched to the position a again to stop the lowering operation of the hook 10 and end the processing. I do.

Accordingly, even if the hook 10 is caught on the tip of the jib 5 and the jib 5 may be overwound, the hook 10 is automatically returned to the safe side, so that the work can be performed safely. Can be.

In the above-described embodiment, when the jib 5, the tower 2, or the hook 10 is overwound, the driving thereof is immediately stopped to drive to the safe side, but the driving is stopped. In doing so, a deceleration operation may be performed. Hereinafter, after the deceleration operation is performed, the second operation for stopping the driving is performed.
An embodiment will be described. Since the structure for deceleration is the same for all of the jib 5, the tower 2 and the hook 10, only the jib 5 will be described here.

FIG. 6 shows a jib 5 according to the second embodiment.
5 is a flowchart for explaining processing performed by the controller 32 when the controller is standing up. In the second embodiment, the position where the jib relative angle θ1R is 18 ° is the overwinding preliminary position of the hoisting rope 6, the jib relative angle θ.
The position where 1R becomes 15 ° is defined as the overwinding position. First, the operation of raising the jib 5 is performed. Then, in step S11, it is determined whether or not the jib 5 has been wound, and the process of step S11 is repeated until step S11 is affirmed. In step S12, the jib relative angle θ1R is set to 18 ° based on the signals from the angle detectors 30 and 34.
, That is, whether or not a preliminary overwinding state has occurred. When step S12 is denied, if it is determined in step S13 that the hoisting operation of the jib 5 has been stopped, this processing is ended. If step S13 is denied, the process returns to step S12 to continue the jib hoisting.

When step S12 is affirmative, the winding speed of the undulating rope 6 is reduced in step S14. In this deceleration process, the controller 32 determines that the jib relative angle θ
In response to the signal representing 1R, the first proportional pressure reducing valve 27 is gradually moved to the position a to reduce the pilot pressure, and the flow rate of the pressure oil passing through the control valve 24 is gradually reduced regardless of the position of the operation lever 25. This is performed by reducing the rotation speed of the auxiliary winding motor 23 by decreasing the rotation speed. When the operation lever 25 is fully operated, the pilot valve 25b outputs the maximum pressure. Therefore, the pilot pressure completely depends on the first proportional pressure reducing valve 27.
When the output pressure of 5b is lower than the control pressure of the first proportional pressure reducing valve 27, the output pressure of the pilot valve 25b is supplied to the pilot chamber 24b. That is, the first proportional pressure reducing valve 27 controls the pilot so that the amount of oil flowing into the motor 23 when the engine speed is the maximum speed and the pump tilt angle is the maximum does not exceed the predetermined jib hoisting speed. Driven to limit the maximum value of pressure.

After the deceleration processing is started in step S14, in step S15, the jib relative angle θ1R is set to 15 ° based on signals from the angle detectors 30 and 34.
Is determined, that is, whether the jib 5 is in an over-wound state. When step S15 is denied, if it is determined in step S16 that the hoisting operation of the jib 5 has been stopped, this process ends. If step S16 is denied, the process returns to step S14 to reduce the jib winding speed. continue.

When step S15 is affirmed, in step S17, the first proportional pressure reducing valve 27 is moved from position b to position a.
Completely switched to the position. As a result, even if the operation lever 25 is operated, the pressure oil supplied from the pilot valve 25b to the pilot chamber 24b of the control valve 24 is shut off, so that the driving of the auxiliary winding motor 23 is stopped. Is also stopped. Then, in step S18, it is determined whether or not the jib 5 has stopped based on the pressure detection signal from the pressure sensor 20A, and if not stopped, the processes of step S17 and step S18 are repeated again. When step S18 is affirmative, in step S19, the first switching valve 26 is moved from the position b to the position a, and the first proportional pressure reducing valve 27 is moved to the position a.
Is completely switched from the position a to the position b. This allows
The pressure oil supplied from the pilot valve 25b to the pilot chamber 24b of the control valve 24 is supplied to the first switching valve 26.
Is reversed from the position at the position b.
Is operated upward, the pressure oil from the pilot valve 25b is supplied to the pilot chamber 24a. Therefore,
The auxiliary winding motor 23 rotates in the direction in which the hoisting rope 6 is fed out, and the jib 5 starts to lower, whereby the jib 5 is released from the overwinding state and automatically returns to the safe side.

Then, in step S20, it is determined whether or not a predetermined time t has elapsed after step S19. If it has elapsed, the first proportional pressure reducing valve 27 is switched to the position a again in step S21. Thus, even if the operation lever 25 is operated, the pressure oil supplied from the pilot valve 25b to the pilot chamber 24a is shut off, so that the driving of the auxiliary winding motor 23 is stopped. Stop and end the process.

As described above, in the second embodiment, before the overwinding state (θ1R = 15 °), the preliminary overwinding state (θ1R = 18 °) is detected, and after the preliminary overwinding state is detected. Since the hoisting speed of the jib 5 is reduced until the overwinding state, even if the jib 5 stops in the overwinding state, the impact of the stop does not act on the crane, and the jib 5 is stabilized without generating a load swing. Work can be done. Also,
Since the upright operation of the jib 5 is stopped by detecting the over-wound state (θ1R = 15 °) and the lowering operation is performed subsequently, the jib 5 can be automatically returned from the over-wound state to the safe side. Work can be done safely.

In the second embodiment,
The jib 5's undulation speed when stopping is reduced, but the tower 2
Alternatively, when the hook 10 is stopped, the undulating speed of the tower 2 or the winding speed of the hook 10 may be reduced.
Further, in the above-described embodiment, the stop operation such as the jib is performed after the overwind is detected, and the lowering operation is performed after confirming the stop. However, the lowering operation is performed according to the overwind detection without performing the stop operation. The operation may be performed. Furthermore, the speed may be limited to a certain speed or less by the proportional pressure reducing valve even when the overwinding detection is lowered.

In the correspondence between the above-described embodiment and the claims, the jib 5 and the tower 2 serve as the raising member,
The undulating drum 4 constitutes undulating means, and the controller 32 constitutes overwinding state releasing means.

[0038]

As described above in detail, according to the first aspect of the present invention, the overwinding state of the undulating means is detected by the overwinding state detecting means, and the overwinding state is released. The operation can be performed safely by automatically avoiding the over-wound state of the slab.

According to the second aspect of the present invention, since the overwinding state detecting means detects the overwinding state of the jib and cancels this state, the overwinding state of the second undulating means is automatically avoided. Work can be done safely. According to the invention of claim 3,
Since the over-wound state detecting means detects the over-wound state of the tower and releases this state, the over-wound state of the first undulating means is automatically avoided, and the work can be performed safely. According to the fourth aspect of the present invention, since the over-wound state detecting means detects the over-wound state of the tower crane and releases this state, the over-wound state of the undulating means is automatically avoided to perform the operation safely. be able to. According to the fifth aspect of the present invention, the overwinding state detecting means detects the overwinding state of the jib and drives and stops the hook lifting / lowering means in a direction to release this state. The work can be safely performed by automatically avoiding the state.

[Brief description of the drawings]

FIG. 1 is a side view showing the configuration of a tower crane.

FIG. 2 is a circuit diagram of a hydraulic circuit for raising and lowering a jib.

FIG. 3 is a circuit diagram of a hydraulic circuit for raising and lowering a tower.

FIG. 4 is a circuit diagram of a hydraulic circuit for raising and lowering a hook.

FIG. 5 is a flowchart of a standing operation of the jib.

FIG. 6 is a flowchart of a jib erecting operation according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crane main body 2 Tower boom 3 Boom hoisting rope 4 Boom hoisting drum 5 Tower jib 6 Boom hoisting rope 8 Pendant rope 9 Jib hoisting auxiliary winding drum 10 Hook 11 Hoisting rope 12 Hoisting main winding drum 21A, 21B Main pump 22A Pilot Pump 23 Supplementary motor 26, 46, 56 Switching valve 27, 47, 57 Proportional pressure reducing valve 32 Controller 43 Undulating motor 53 Main motor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B66C 23/88 B66D 1/54

Claims (5)

(57) [Claims] At least one of an undulating means and an undulating means.
An elevating means comprising two elevating members, and an angle at which an overwinding state which is an unsuitable angle state for the operation of the elevating member is detected and the undulating means is driven in a direction to release the overwinding state , thereby enabling an operation. An overwinding prevention device for a crane, comprising: an overwinding state releasing unit that stops in a state. 2. A tower which is raised and lowered by first raising and lowering means, a jib which is raised and lowered by second raising and lowering means, and an overwinding state which is an angle state unsuitable for the work of the jib is detected to detect the overwinding. An overwinding prevention device for a crane, comprising: an overwinding state releasing unit that drives the second undulating unit in a direction in which the state is released , and stops at an angle state that enables work . 3. A tower which is raised and lowered by first raising and lowering means, a jib which is raised and lowered by second raising and lowering means, and an overwinding state which is an angle state unsuitable for work of the tower is detected. An overwinding prevention device for a crane, comprising: an overwinding state releasing unit that drives the first undulating unit in a direction in which the state is released , and stops at an angle state that enables work . 4. A crane boom that is raised and lowered by the raising and lowering means, and an overwinding state that is an angle state that is not suitable for the operation of the crane boom is detected, and the raising and lowering means is driven in a direction to release the overwinding state . An overwinding prevention device for a crane, comprising: an overwinding state release unit that stops at an angle that enables work . 5. The apparatus according to claim 1, further comprising a hook elevating means for elevating and lowering the hook, wherein the overwinding state releasing means is suitable for the work of the jib.
When the overwinding state is detected, which is an angle state that does not occur, the hook lifting / lowering means is driven in a direction to release the overwinding state ,
3. The overwinding prevention device for a crane according to claim 2, wherein the crane stops at a position where the work can be performed .