JPH1017277A - Safety device of tower crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crane which can limit the rising/falling force to an appropriate value when a boom, etc., is making the derrick motions. SOLUTION: A safety device concerned of a tower crane is composed of a tower boom installed as capable of derrick motion, a jib installed at the tip of the tower boom with possibility of derrick motion, solenoid-operated proportioning control valves 34 and 42 to limit the rising/falling force to generate motions of the tower boom and/or jib to a level below the specified value, and angle sensors 21 and 22 to sense the attitudes of the tower boom and jib, wherein the limit values of the valves 34 and 42 are altered in conformity to the signals given by the angle sensors 21 and 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tower crane having a tower boom and a jib, and a crane having a crane boom.

[0002]

2. Description of the Related Art There is known a tower crane which uses a microswitch to detect an abnormal posture of a tower boom and a jib in order to avoid damage to a structure caused by overwinding of an up-and-down winch. Technology 1). For example, a push plate interlocking with the tower boom is provided near the rotation axis of the tower boom, and by pressing a micro switch provided on the tower crane main body with the push plate, an abnormality in the angle of the tower boom can be detected. . In addition, by pushing a micro switch attached to the tip of the tower boom with a push plate interlocked with the jib, an abnormality in the jib angle can be detected. When the microswitch detects an abnormality in the angle of the tower boom or jib, a stop signal for raising the hoisting winch is output, and the tower boom or jib stops, so that damage to the structure can be prevented.

Further, a mobile crane has been disclosed which limits the winch force of a suspended load winch to a predetermined value or less in a running posture to prevent damage to the crane in the running posture (Japanese Utility Model Laid-Open No. 55-176288). Prior art 2). Japanese Patent Application Laid-Open No. 7-215679 (Prior Art 3) discloses that a rope tension is detected as a safety device for a tower crane, and the rope tension is compared with a preset turbulence generation limit tension or breakage limit tension. When the rope tension reaches these limit tensions, a winch is stopped to prevent the rope from being wound and the tower attachment from being damaged.

[0004]

However, in a crane which uses a microswitch to prevent overwinding (prior art 1), an adjustment operation for properly operating the microswitch is complicated, and a shock or the like is required. As a result, when the push plate is deformed, normal operation cannot be ensured. In addition, before starting work, it is necessary to check the operation of the micro switch as a pre-operation check.However, it is necessary to raise and lower the tower boom or jib until the micro switch is operated, and if the micro switch is broken, The winding prevention is not activated, and the elevating rope may be overwound and damage the crane structure.

When the tower boom of the tower crane is set to the working posture, the boom elevating rope is firstly hoisted by a winch to bring the tower boom upright, and then a connection for fixing the folded jib to the boom. Remove the device and wind up the jib elevating rope.
However, if the jib elevating rope is wound up without forgetting to remove the connecting device, the structure of the crane may be damaged.

Further, in the crane of the prior art 2, although damage in the running posture is prevented, it is not possible to prevent damage to the structure when elevating the boom or the like at the time of work, for example. In the tower crane of the prior art 3,
The hoisting and unwinding operation of the rope is stopped by comparing the uniquely determined tension limit value with the rope tension detected by the rope tension detector, and the rope is adjusted according to the posture of the tower boom or jib. The tension is not limited, and the limit value cannot be set finely in accordance with various postures.

An object of the present invention is to provide a crane capable of restricting the up-and-down force at the time of raising and lowering a boom or the like to an appropriate value.

[0008]

FIG. 1 shows an embodiment of the present invention.
Explaining in association with (1) to (2), the invention according to claim 1 is:
Tower fronts 2 and 3 each including a main body 1, a tower boom 2 movably mounted on the main body 1, and a jib 3 movably mounted on the tip of the tower boom 2.
And a winch device 4,13 for raising and lowering the tower fronts 2,3. Then, attitude detecting means 21 and 22 for detecting the attitude of the tower fronts 2 and 3 and adjusting means 3 for adjusting the undulating force of the tower fronts 2 and 3 by the winch devices 4 and 13.
4 and 42, and controls the adjusting units 34 and 42 based on the postures detected by the posture detecting units 21 and 22.
The above-mentioned object is achieved by adjusting the undulating force of the tower fronts 2, 3. According to a second aspect of the present invention, a tower front 2 includes a main body 1, a tower boom 2 movably mounted on the main body 1, and a jib 3 movably mounted on the tip of the tower boom 2.
And posture detecting means 21 and 22 for detecting the posture of the tower fronts 2 and 3, which are applied to a safety device of a tower crane provided with winch devices 4 and 13 for raising and lowering the tower fronts 2 and 3. 13, adjusting means 34, 42 for adjusting the undulating force of the tower fronts 2, 3 by the adjusting means 34, 42.
The above-mentioned object is achieved by restricting the undulating force of the tower 3 to the allowable undulating force for each attitude of the tower fronts 2 and 3. According to a third aspect of the present invention, in the tower crane safety device according to the second aspect, it is possible to perform a crane operation on the allowable up-and-down force of the tower fronts 2 and 3 for each posture of the tower fronts 2 and 3 and to operate the tower front 2. , 3 and the attitude limiters 2a, 15, 17 are smaller than the damage limit value. According to a fourth aspect of the present invention, in the tower crane safety device according to any one of the first to third aspects,
The adjusting means 34 and 42 adjust the undulating force of the tower fronts 2 and 3 based on the signals from the attitude detecting means 21 and 22 and the number of layers of the wire rope wound around the winch devices 4 and 13. . The invention according to claim 5 includes a tower boom 2 movably mounted, and a jib 3 movably mounted at a tip of the tower boom 2,
A first blocking means 17 for preventing the tower boom 2 from tilting backward from a predetermined position; a second blocking means 15 for preventing the jib 3 from moving upward from a predetermined position; First winch device 4 raised and lowered via 7
And a second winch device 13 for raising and lowering the jib 3 via a second hoisting rope 12, and a guide crane provided with guide means 8 for guiding the second hoisting rope 12 toward the jib 3. Is done. Then, the first winch device 4
A tower boom hoisting force adjusting means 34 for adjusting the hoisting force of the tower boom 2 by means of;
Posture detecting means 21 and 22 for detecting the posture of the tower boom 2 and the jib 3 are provided. The tower boom undulating force adjusting means 34 and the jib undulating force adjusting means 42
The above object is achieved by limiting the tower boom undulating force and the jib undulating force to predetermined values based on signals from the first and second signals, respectively. According to a sixth aspect of the present invention, in the safety device for a tower crane according to the fifth aspect, the predetermined value is determined by the posture of the tower boom 2 and the jib 3 and the workable undulating force based on the posture and the first blocking means 15. , The second blocking means 17 and the guide means 2a are set to an undulating force which will not be damaged. According to a seventh aspect of the present invention, in the tower crane safety device according to the fifth or sixth aspect, the tower boom hoisting force adjusting means 34 and the jib hoisting force adjusting means 42 use the signals from the attitude detecting means 21 and 22 and the first signal. The undulating force of the tower fronts 2, 3 is adjusted based on the number of windings of the wire rope wound around the second winch devices 4, 13. The invention of claim 8 is the invention of claim 1
7. The safety device for a tower crane according to any one of the above items, wherein the angle detectors 21 and 22 for detecting the angle of the tower boom 2 and the angle of the jib 3 are used as the posture detecting means.

In the meantime, in the section of the means for solving the above-mentioned problem which explains the constitution of the present invention, the drawings of the embodiments of the present invention are used in order to make the present invention easy to understand. It is not limited to the example.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

-First Embodiment- Hereinafter, a first embodiment of a tower crane according to the present invention will be described with reference to FIGS. FIG. 1 is a side view showing an embodiment of a tower crane according to the present invention. In FIG. 1, reference numeral 1 denotes a crane main body, 2 denotes a tower boom pivotally supported by the crane main body 1, and 3 denotes a jib pivotally supported by a tip end portion of the tower boom 2.
In this embodiment, the tower boom 2 and the jib 3 are collectively called a tower front. 4 is a tower boom hoisting winch drum mounted on the crane body 1, 5 is a first pendant rope having one end connected to the tip of the tower boom 2, and 6 is a first pendant rope to which the other end of the first pendant rope 5 is attached. 1
Is a tower boom hoisting rope wound around the tower boom hoisting winch drum 4, and is wound around the first bridle device 6 and the A frame hanger device 6A a plurality of times. The tower boom 2 is raised and lowered by driving the tower boom hoisting winch drum 4.

Numeral 8 is a triangular swing lever rotatably supported at the tip of the tower boom 2. The vertical angle of one of the swing levers 8 is set at the tip of the jib 3 via a second pendant rope 9. One end of a third pendant rope 10 is attached to the other apex. Third
The other end of the pendant rope 10 is connected to a second bridle device 11. The jib hoisting rope 12 is wound around a jib hoisting winch drum 13 mounted on the crane main body 1, and has a second bridle device 11 and a hanger device 11A.
Is multiplied several times between The swing lever 8 is rotated clockwise and counterclockwise by the jib hoisting winch drum 13 to move the jib 3 up and down.

A guide roller 2a is protrudingly provided on the rear side of the distal end of the tower boom 2. The swing lever 8 is shown in FIG.
The third pendant rope 10 approaches the tower boom 2 when rotated clockwise from the state shown in FIG.
0 contacts the guide roller 2a. When the third pendant rope 10 is extended and retracted in this state, the guide roller 2a rotates to support the third pendant rope 10 (see FIG. 7).

Reference numeral 14 denotes a hook suspended from the tip of the jib 3, and is a main winch (not shown) mounted on the main body.
Of the rope 14a at the same time, the hook 14
Moves up and down.

Reference numeral 15 denotes a back stop protruding from a rear portion of the jib 3 and abuts against a plate (not shown) at the tip of the tower boom 2 so that the jib 3 does not move backward beyond a predetermined angle. To limit the elevation of jib 3. Reference numeral 17 denotes a backstop interposed between the rear portion of the tower boom 2 and the crane main body 1, which prevents the tower boom 2 from moving backward beyond a predetermined angle. Reference numeral 18 denotes a jib connecting device that connects the jib 3 that has been rotated (downward) clockwise in FIG. 1 and folded to the tower boom 2.

A tower angle detector 21 is attached to the tower boom 2 and detects the angle of the tower boom 2.
Is a jib angle detector which is attached to the jib 3 and detects the angle of the jib 3. The tower angle detector 21 and the jib angle detector 22 generally include an elevation angle of the tower boom 2 (tower angle: θt) and an elevation angle of the jib 3 (jib angle) with respect to a reference angle when the horizontal is set to a reference angle (0 degree). : Θj
) Are respectively detected. In this embodiment, for the sake of explanation, the tower angle θt is set to a horizontal reference angle (0 degree), and the jib angle θj is set to a relative angle with respect to the tower boom 2.

FIG. 2 shows a hydraulic circuit and a control circuit (electric circuit) of the tower crane according to the first embodiment. As shown in FIG. 2, a hydraulic motor 31 and a hydraulic pump 32 are connected to a direction control valve 33, an electromagnetic proportional pressure control valve 34, a counter balance valve 35, and a crossover load relief valve 36.
The oil discharged from the hydraulic pump 32 is discharged to the tank 37 by rotating the hydraulic motor 31. As shown in FIG. 2, the hydraulic motor 40 and the hydraulic pump 39 are connected by a pipe via a directional control valve 41, an electromagnetic proportional pressure control valve 42, and a counterbalance valve 43, and discharge from the hydraulic pump 39 is performed. The oil is discharged to the tank 44 by rotating the hydraulic motor 40.

The above-mentioned tower boom hoisting winch drum 4
Is connected to the drive shaft of the hydraulic motor 31 so that the tower boom hoisting rope 7 is extended and retracted with the rotation of the hydraulic motor 31. The above-mentioned jib hoisting winch drum 13 is connected to the drive shaft of the hydraulic motor 40, and the jib hoisting rope 12 is rotated by the rotation of the hydraulic motor 40.
Is carried out and carried over.

As shown in FIG. 2, the control unit 50 controls the A / D
Converter 51, computer 52, memory 53 and D /
An angle signal from the tower angle detector 21 and the jib angle detector 22 is input to the control device 50 via the A / D converter 51. The control device 50 that has received the angle signal outputs a command voltage via the D / A converter 54, and the command voltage is input to the solenoid controller 60. Further, the solenoid controller 6
An output signal of 0 (command current) is applied to the above-described coils of the electromagnetic proportional pressure control valve 34 and the electromagnetic proportional pressure control valve 42, and the relief pressure of the electromagnetic proportional pressure control valves 34 and 42 is controlled.

The memory 53 stores the values of the tower angle θt and the jib angle θj, that is, the relief pressures of the electromagnetic proportional pressure control valves 34 and 42 corresponding to the attitude of the tower front. When the tower angle .theta.t and the jib angle .theta.j are input to the computer 52 via the controller 52, the relief pressures of the electromagnetic proportional pressure control valves 34 and 42 corresponding to the tower angle .theta.t and the jib angle .theta.j at that time are read from the memory 53. Then, the relief pressure read by the computer 53 is D / A converted by the D / A converter 54, and becomes a command voltage. Upon receiving the command voltage, the solenoid controller 60 operates the electromagnetic proportional pressure control valve 34.
And the command current is sent to the solenoid 42, so that the relief pressure of the electromagnetic proportional pressure control valves 34 and 42 is controlled according to the information of the memory 53 set in advance.

When the hydraulic pressure P1 when the tower boom 2 elevates reaches the relief pressure of the electromagnetic proportional pressure control valve 34, the electromagnetic proportional pressure control valve 34 opens, so that the hydraulic pressure P1 is suppressed to the relief pressure or less. Also, when the hydraulic pressure P2 when the jib 3 moves up reaches the relief pressure of the electromagnetic proportional pressure control valve 42, the electromagnetic proportional pressure control valve 42 is opened, so that the hydraulic pressure P2 is suppressed to the relief pressure or less.

Next, an example of the attitude detection of the tower front based on the tower angle θt and the jib angle θj detected by the tower angle detector 21 and the jib angle detector 22 and an example of the relief pressure setting stored in the memory 53 are shown in FIG. ~ Figure 1
2 will be described. 6 shows a state where the jib 3 is fixed to the tower boom 2 by the connecting device 18 and the tower boom 2 lands on the ground, for example, a posture before work. In this posture, the tower angle θt = 0 ° and the jib angle θj = 0 °. That is, when the tower angle θt = 0 ° and the jib angle θj = 0 °, the jib 3 is held in the tower boom 2 and the connecting device 1
In a state where the tower boom 2 is connected at 8, the tower boom 2 can be said to be in a posture of landing on the ground. In this position, when the jib hoisting rope 12 is wound by the jib hoisting winch drum 13, the tension of the pendant rope 10 causes the guide roller 2a to move.
Generates a compressive force on the guide roller 2a depending on excessive winding.
The relief setting pressure in this position is determined by the jib undulation force, that is, the rope winding torque of the jib undulation winch drum 13 is reduced by the guide roller 2a.
Is set to a value that will not cause damage.

In the position shown in FIG. 7, the tower angle detector 21 and the jib angle detector 22 each have a tower angle θt = 3.
0 ° jib angle θj = 0 ° is detected. This state is
6 shows a state in which the tower boom 2 is raised in a state where the jib 3 is connected to the tower boom 2 by the connecting device 18, for example, a state in which the jib 3 is in the working posture from the state of FIG. 6. FIG.
, The tower angle detector 21 and the jib angle detector 22 respectively have a tower angle θt = 60 ° and a jib angle θj =
0 ° is shown. In this state, the jib 3 is connected to the connecting device 18.
7 shows a state where the tower boom 2 is further raised from the state shown in FIG.
7 and 8, when the tower boom 2 is raised, in order to prevent the jib hoisting rope 12 from sagging due to the hoisting of the tower boom 2, the jib hoisting rope is wound simultaneously with the hoisting of the tower hoisting rope 7. Need to do. As described above, if the jib hoisting rope 12 is excessively wound, the guide roller 2a may be damaged.
Also in the postures shown in FIGS. 7 and 8, the relief setting pressure is set to a value such that the jib hoisting force, that is, the rope winding torque of the jib hoisting winch drum 13 does not damage the guide roller 2a.

In the posture shown in FIG. 9, the tower angle detector 21 and the jib angle detector 22 each have a tower angle θt = 9.
0 indicates a jib angle θj = 0 °. In this state, the jib 3 is connected to the tower boom 2 by the connecting device 18 and the tower boom 2 stands upright. Here, for the sake of explanation, the tower angle θt is 90 °, but the angle is actually slightly smaller in consideration of safety. When the jib hoisting rope 12 is hoisted in order to bring the jib 3 up to the working posture from this state, the connecting device 18
If the user forgets to remove the jib, the tension of the jib hoisting rope 12 increases, and the guide roller 2a may be damaged as described above. If the tower hoisting rope 7 is wound in this state, the backstop 17 for preventing the tower boom 2 from tilting backward or its mounting portion may be damaged.
Therefore, the relief setting pressure in this case is the jib up / down force, that is, the value at which the rope winding torque of the jib up / down winch drum 13 does not damage the guide roller 2a, and the tower boom up / down force, that is, the tower up / down winch drum 4. The winding torque is set to a value that does not damage the backstop 17 and its mounting part.

In the posture of FIG. 10, the tower angle detector 21
And the jib angle detector 22 respectively provide the tower angle θt
= 90 ° jib angle θj = 45 °, the posture of FIG. 11 shows a tower angle θt = 90 ° jib angle θj = 110 °, and the posture of FIG. 12 shows a tower angle θt = 90 ° jib angle θj = 150.゜ is shown. These postures show a process until the connecting device 18 is released and the jib is brought into a predetermined working state. In this process, if the jib is moved up and down beyond the state shown in FIG. 12, the backstop 15 comes into contact with the abutment plate (not shown) at the tip of the tower boom 2 and the jib 3
However, if the jib 3 is further wrapped around the jib 3 and a force is applied to tilt the jib 3 backward, the backstop 15 may be damaged. for that reason,
10 to 12, that is, when the connecting device 18 is released and the jib can be raised and lowered, the relief setting pressure is used to increase the jib's up / down force, that is, the rope winding torque of the jib up / down winch drum 13 increases the jib's up / down. The value is set so that work is possible and the backstop 15 is not damaged.

Similarly, in the case of carrying out the lifting work including the raising and lowering of the tower boom called luffing, the relief setting pressure is the raising and lowering force of the tower boom, that is, the rope winding torque of the tower raising and lowering winch drum 4 is controlled by the tower boom raising and lowering. The value is set to a value at which work is possible and the backstop 17 is not damaged. Here, the torque capable of performing the jib hoisting operation, luffing and preventing damage to the backstops 15 and 17 satisfies a value of a known rated load table based on a load of a suspended load provided in advance on the crane and a working radius. While preventing damage to the backstop,
As shown in FIG. 3 and FIG. 4, it changes depending on the tower angle and the jib angle. The above-mentioned numerical values of the relief set pressures are values determined by design in consideration of the strength of the guide roller 2a and the backstops 15 and 17, and the like. One or both of the solenoid valve proportional pressure control valves 34 and 42 are controlled based on the relief pressure set based on the above conditions.

<Operation Sequence> Next, an operation sequence of this embodiment will be described with reference to FIG. In step S1 of FIG. 5, the output signals of the tower angle detector 21 and the jib angle detector 22 (tower angle θt, jib angle θ
j) is read into the computer 52. In step S2, the attitude of the tower front is determined from these angles. In the following step S3, the relief pressure set for each tower front posture is read from the memory 53 based on the information in step S2. Then, in step S4, step S3
Control valve 3 based on the relief pressure read in
Command voltages to 4 and 42 are calculated and command voltages are sent to solenoid controller 60. By returning from step S4 to step S1, step S1
Step S4 is repeated, so that the electromagnetic proportional pressure control valves 34 and 4 follow the change in the attitude of the tower front based on the tower angle θt and the jib angle θj.
2 is controlled.

As described above, in the tower crane of the present embodiment, the tower hoisting force and the jib hoisting force are restricted in advance according to the tower front posture based on the tower angle θt and the jib angle θj. The tower crane can be prevented from being damaged while securing the necessary undulating force at the respective tower angle θt and jib angle θj. In addition, the tower angle detector and jib angle detector can use existing ones used for crane safety devices such as the well-known moment limiter, and there is no need to add a new detector such as a tension detector. The configuration can be simplified, and the reliability against failure can be increased.

In the present embodiment, the relief pressure itself corresponding to the tower angle θt and the jib angle θj is written in the memory 53 in the form of a list.
May be written with only data necessary for calculating the relief pressure, and the computer 52 may calculate the relief pressure.

Although the first embodiment has described the case of a tower crane, the present invention relates to other cranes,
For example, the present invention is also applicable to a crane having no tower boom, and in that case, any configuration related to the above-described tower boom 2 or jib 3 may be used.

Second Embodiment As shown in FIG. 13, the second embodiment is different from the first embodiment in that the electromagnetic proportional pressure control valve 34 is replaced with a relief valve 34A and a relief valve 34B. , An electromagnetic on-off valve 34C, and an electromagnetic on-off valve 34D. Relief valve 34
A and the relief pressure of the relief valve 34B are different values,
The electromagnetic on / off valves 34C and 34C are supplied with current from the control device 50 having received the information on the tower angle θt and the jib angle
D is opened and closed.

In the second embodiment, the solenoid on-off valves 34C and 34C depend on the tower angle θt and the jib angle θj.
D is opened, and the oil pressure is limited to the relief pressure of the relief valves 34A and 34B. Therefore, similarly to the first embodiment, the tower hoisting force is reduced by the tower angle θt and the jib angle θj.
Can be suppressed below the limit value corresponding to

In the second embodiment, two relief valves 34A and 34B having different relief pressures are used. However, by using three or more relief valves, the relief force is further restricted by a multistage relief pressure. You may do so. The hydraulic circuit for raising and lowering the jib 3 may be provided with a similar relief valve and an electromagnetic on-off valve. In this case, similarly to the tower lifting and lowering force, the jib raising and lowering force can be controlled to a predetermined limit value or less.

Third Embodiment In a third embodiment, a winding layer correction is performed in calculating the relief pressure of the electromagnetic proportional control valves 34 and 42.
Since the structure of the crane of the third embodiment is the same as that of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted.

When the tower hoisting rope 7 is wound around the tower hoisting winch drum 4 in a pile, the diameter of the drum is substantially increased by the number of layers of the ropes 7, so that the hoisting force is affected. Out. A similar phenomenon occurs when the jib hoisting winch rope 12 is wound around the jib hoisting winch drum 13. In this case, the electromagnetic proportional control valve 3 is controlled in consideration of the influence of the ropes 7 and 12 on the undulating force.
If the relief pressures of the ropes 4 and 42 are calculated, the length of the tower hoisting rope 7, the jib hoisting rope 12, the pendant rope 5, or the pendant rope 10, the length of the tower boom 2, or the jib 3 is changed. ,
Even when the tower boom or jib is replaced), the limit values of the tower hoisting force and the jib hoisting force can be set to optimal values.

As shown in FIG. 15, the attitude of the tower front (tower boom 2 and jib boom 3) is calculated by the computer 52 based on the output signals of the tower boom angle detector 21 and jib boom angle detector 22,
Further, based on the calculated tower front posture, tower boom length data, jib length data, and rope length data (tower boom hoisting rope 7, jib hoisting rope 12, and pendant ropes 5, 9) read from the memory 61, and the like. The winch winding layer is calculated. The command voltage to the solenoid controller 60 is corrected based on the relief pressure set according to the attitude of the tower front and the relief pressure correction data set according to the winch winding layer read from the memory 61. You.

FIG. 14 shows the computer 5 shown in FIG.
3 is a flowchart simply illustrating the process of FIG. FIG.
In step S11, the tower angle θt and the jib angle θj are read from the signals of the tower angle detector 21 and the jib angle detector 22. In step S12, the tower angle θt and the jib angle θ read in step S11
Determine the attitude of the tower front from j. Step S1
In step 3, the tower boom hoisting rope length data, the jib hoisting rope length data, the tower boom length data, and the jib length data written in the memory 61 are read. Step S
At step 14, the tower hoist winch drum 4 and the jib hoist winch drum 13 are determined based on the data read in step S13 and the tower front posture determined in step S12.
Calculate the number of winding layers of the undulating ropes 2 and 12 wound up. In step S15, the relief pressure set for each tower front posture and the relief pressure correction data corresponding to the number of winding layers calculated in step S14 are read from the memory 61. In step S16, the command voltage of the electromagnetic proportional pressure control valve 34 or 42 is calculated based on the information in step S15 in consideration of the number of winding layers of the winch drum, and the calculated command voltage is sent to the solenoid controller 60. . After step S16 ends, the process returns to step S11, so that the sequence of steps S11 to S16 is repeated.

An example of the above-described method for determining the number of winding layers will be described with reference to the case of the jib hoisting winch drum 13 as an example. Tower boom 2 length, jib 3 length, pendant rope 5
, The length of the pendant rope 9, the tower angle θt and the jib angle θj, the coordinates of the connection point between the swing lever 8 and the pendant rope 10 can be found. From these coordinates,
The distance between the second bridle device 11 and the hanger device 11A is known. Shaft center of winch 13 and hanger device 11A
Is known to the sheave axis. The number of rope loops between the second bridle device 11 and the hanger device 11A is known. The distance between the second bridle device 11 and the hanger device 11A is multiplied by the number of turns, and the length of the rope wrapped around the sheave is added, and the payout rope length is determined from the input known full length of the rope (the total length of the undulating rope).
The drum diameter and drum width are known, and the winding layer is determined. Therefore, the sequentially detected tower angle θt and jib angle θj
, The lengths of the pendant ropes 5 and 9 that have been input, and the length of the hoisting rope (tower boom hoisting rope 7, jib hoisting rope 1
The length is determined in real time on the basis of various data previously input to the memory 53.

In the third embodiment, since the relief pressure is corrected by the number of winding layers of the drums 4 and 13, the limit values of the tower hoisting force and the jib hoisting force can be set to accurate values. Further, the limit value of the undulating force can be accurately set in accordance with the exchange of the tower boom or jib or the change of the rope length.

The present invention is not limited to application to a tower crane equipped with a tower boom and a jib, but can be widely applied to a crane equipped with a crane boom.

[0040]

According to the present invention, since the limit value of the undulating force is changed in accordance with the signal from the posture detecting means, the undulating force can be appropriately suppressed in accordance with the change in the posture. .

[Brief description of the drawings]

FIG. 1 is a side view of a tower crane showing a first embodiment of a tower crane safety device according to the present invention.

FIG. 2 is a diagram showing a hydraulic circuit and a control circuit (electric circuit) of the tower crane safety device according to the first embodiment.

FIG. 3 is a diagram illustrating a limit value of a tower hoisting force of the tower crane safety device according to the first embodiment.

FIG. 4 is a diagram showing a limit value of the jib hoisting force of the safety device for the tower crane according to the first embodiment.

FIG. 5 is a flowchart illustrating an operation sequence of the safety device for the tower crane according to the first embodiment.

FIG. 6 is a state explanatory view illustrating the attitude of the tower front of the safety device for the tower crane according to the first embodiment.

FIG. 7 is a state explanatory diagram illustrating the attitude of the tower front of the safety device for the tower crane according to the first embodiment.

FIG. 8 is a state explanatory view illustrating the attitude of the tower front of the safety device for the tower crane according to the first embodiment.

FIG. 9 is a state explanatory view illustrating the attitude of the tower front of the safety device for the tower crane according to the first embodiment.

FIG. 10 is a state explanatory view illustrating the attitude of the tower front of the safety device for the tower crane according to the first embodiment.

FIG. 11 is a state explanatory view illustrating the attitude of the tower front of the safety device for the tower crane according to the first embodiment.

FIG. 12 is a state explanatory view illustrating the attitude of the tower front of the safety device for the tower crane according to the first embodiment.

FIG. 13 is a diagram illustrating a hydraulic circuit of a safety device for a tower crane according to a second embodiment.

FIG. 14 is a flowchart illustrating an operation sequence of the safety device for the tower crane according to the third embodiment.

FIG. 15 is a diagram showing a calculation procedure for correcting the number of turns of the safety device for the tower crane according to the third embodiment.

[Explanation of symbols]

 2 Tower boom 3 Jib 21 Tower angle detector 22 Jib angle detector 34 Electromagnetic proportional control valve 42 Electromagnetic proportional control valve

Claims (8)

[Claims] A tower front comprising: a main body; a tower boom attached to the main body so as to be able to move up and down; and a jib attached to a tip end of the tower boom so as to be able to move up and down; a winch device for moving the tower front up and down; A safety device for a tower crane, comprising: a posture detection unit configured to detect a posture of the tower front; and an adjustment unit configured to adjust an up / down force of the tower front by the winch device, wherein the detection is performed by the posture detection unit. A safety device for a tower crane, wherein an adjusting means is controlled based on a posture to adjust an undulating force of a tower front. 2. A tower front including a main body, a tower boom movably mounted on the main body, and a jib mounted movably on a distal end of the tower boom, and a winch device for raising and lowering the tower front. A safety device for a tower crane, comprising: a posture detection unit configured to detect a posture of the tower front; and an adjustment unit configured to adjust an up-and-down force of the tower front by the winch device. A safety device for a tower crane, wherein an undulating force is limited to an allowable undulating force for each posture of the tower front. 3. The safety device for a tower crane according to claim 2, wherein a permissible undulation force of the tower front for each posture of the tower front is smaller than a crane workable limit value of the tower front. A safety device for a tower crane, comprising: 4. The safety device for a tower crane according to claim 1, wherein the adjusting unit is configured to control a signal from the posture detecting unit and a winding number of a wire rope wound around the winch device. A safety device for a tower crane, which adjusts the undulating force of a tower front based on a vehicle. 5. A tower boom movably mounted, a jib movably mounted at a tip of the tower boom, and a first boom for preventing the tower boom from tilting backward from a predetermined position.
A first winch device for raising and lowering the tower boom via a first raising and lowering rope; a second winching device for raising and lowering the tower boom via a first raising and lowering rope; 2nd up and down movement through 2 up and down ropes
A tower crane comprising: a winch device; and a guide means for guiding the second hoisting rope toward the jib. A tower boom hoisting force adjustment for adjusting the hoisting force of the tower boom by the first winch device Means, jib up / down force adjusting means for adjusting the up / down force of the jib by the second winch device, and attitude detecting means for detecting the attitude of the tower boom and the jib, the tower boom up / down force adjusting means And a jib hoisting force adjusting means for limiting the tower boom hoisting force and the jib hoisting force to predetermined values based on a signal from the attitude detecting means, respectively. 6. The safety device for a tower crane according to claim 5, wherein the predetermined value is a posture of the tower boom and the jib;
A safety device for a tower crane, which is set to an undulating force operable based on the posture and an undulating force that does not damage the first blocking means, the second blocking means, and the guide means. 7. The tower crane safety device according to claim 5, wherein the tower boom hoisting force adjusting means and the jib hoisting force adjusting means include a signal from the attitude detecting means and the first and second signals.
A safety device for a tower crane, wherein the undulating force of a tower front is adjusted based on the number of windings of a wire rope wound around a second winch device. 8. The safety device for a tower crane according to claim 1, wherein the attitude detecting means is an angle detector that detects an angle of the tower boom and an angle of the jib. A safety device for a tower crane.