JPH11171480A - Overwind preventer of crane's wire rope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the height of ground lift securable as far as the same degree and the changeover of both low and high speed modes being suited for satisfying the structural specifications of a crane, freely performable. SOLUTION: This wire rope overwind preventer is provided with a stop starting signal detecting means 5 detecting a point of time when a hook 4 is situated in a position nearer to a tip part than a specified first position 6 downwards from the tip part of a boom 1 and generating a stop starting signal SL, a low speed transfer signal detecting means 10 detecting a point of time when the hook 4 is situated a position nearer to the tip end than a specified second position 11 apart from the tip part of the boom 1 more than the first position 6 and generating a transfer signal SH to a low speed, and a judging means inputting a signal S1 stopping the rotation of a winch 22 at a time when the stop starting signal SL is monitored in time of a low speed mode ML and this stop starting signal SL is inputted, on the other hand, at the time when the stop starting signal S1 and the transfer signal SH to the low speed are monitored in time of a high speed mode MH, inputting a signal S2 switching the rotation of the winch to the low speed, and inputting the signal S1 stopping the rotation of this winch when the stop starting signal SL is inputted, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing winding of a wire rope of a crane.

[0002]

2. Description of the Related Art According to the construction standards of cranes, hooks,
The upper surface of a hanging device such as a grab bucket or the like, the sheave at the tip of a boom or jib (hereinafter, the jib is also included in the “boom”), the lower surface of any other object that may contact the upper surface, and the upper surface of the hanging device Is specified to be equal to or greater than a predetermined value. For this reason, a direct-acting type winding prevention device is used for a mobile crane and the like. FIG. 6 is a configuration diagram of a conventional direct acting type winding prevention device. A hook 4 is attached to a tip of a wire rope 3 wound around a load sheave 2 attached to a tip of a boom 1. A switch 5 is mounted near the load sheave 2, and a weight 6 is movably engaged with the wire rope 3 at a position at a predetermined interval A below the lower end of the boom 1. The weight 6 is suspended from the switch 5 by a connecting rope 7.

When the wire rope 3 is wound up and the hook 4 comes into contact with the weight 6, the connecting rope 7 is loosened and the switch 5 is operated as shown in FIG. The winch is stopped by unloading the hydraulic pressure, and the wire rope 3 is automatically prevented from being overwound. At this time, due to the time lag of the winch stop operation and the inertia force of the wire rope 3 and the hook 4, the hook 4
Bounce up, and the weight 6 stops at a position B (B <A) below the lower end of the boom 1. The distance B must be equal to or greater than the value defined in the structural standard of the mobile crane described above. Therefore, the distance A is set in consideration of the amount of the hook 4 jumping up.

[0004]

However, in the above configuration, the distance B depends on the time lag and the inertia between the wire rope 3 and the hook 4, and is therefore affected by the winch winding speed. The greater the winding speed, the smaller the distance B becomes. Become. Therefore, in the case of a high-speed hoisting drive in which the hoisting speed is high (especially, in addition to the low-speed mode ML which is a normal hoisting and unwinding speed, for example, the highest The initial distance A must be very large in advance (for a crane having a switchable high speed mode MH for achieving a winding speed much higher than the speed). However, when the interval A is increased, the ground lifts C and C ′ shown in FIG. 6 are reduced, and the performance of the crane is reduced.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a crane having a wire rope suitable for crane which can switch between low speed and high speed modes, and which can secure the same ground lift and satisfy the crane's structural standards. An object is to provide a winding prevention device.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, a crane wire rope overwind prevention device according to the present invention is described with reference to, for example, the elements of FIGS. First, hook (4) at the tip
A wire rope (3) that can be wound down from the tip of the boom (1), and a winch (3) that can be switched between low-speed and high-speed modes (ML, MH) to wind and unwind the wire rope (3). (22), mode switching means (21) which is switched between low speed and high speed modes (ML, MH), and stoppage of rotation of winch (22) to prevent overwinding of wire rope (3) In a crane wire rope winding prevention device having a stop start signal detecting means for detecting a start time, (a) a hook (4) is provided at a predetermined first position (6) below a tip of a boom (1). ), A stop start signal detecting means (5) for generating a stop start signal (SL) at the time of this detection, and (b) a hook (4) comprising a first position.
Detects a position closer to the tip than a predetermined second position (11) farther from the tip of the boom (1) than (6), and generates a low speed switching signal (SH) upon this detection. (C) a stop start signal detecting means (5),
(C1) Mode switching means electrically connected to the low speed switching signal detecting means (10), the mode switching means (21) and the winch (22).
When the switching signal from (21) is in the low-speed mode (ML), monitor the input of the stop start signal (SL) from the stop start signal detection means (5) and output the stop start signal (SL) to be monitored. When input, a signal (S1) for stopping the rotation of the winch (22) is input to the winch (22), and (c2) mode switching means (21)
When the switching signal from the controller is in the high speed mode (MH), the input of the stop start signal (SL) from the stop start signal detecting means (5) and the switching signal to the low speed from the low speed switching signal detecting means (10) ( SH) and the input signal (S2) for switching the rotation of the winch (22) to low speed when the switching signal (SH) for low speed to be monitored is input, and the stop start signal (SL) And a determination means (20) for inputting a signal (S1) for stopping the rotation of the winch (22) to the winch (22) when the input is input.

According to the first configuration, the mode switching means 2
1, the hook 4 satisfies the standard position and the boom 1 is moved from the tip end of the boom 1 regardless of whether the mode is switched to the low speed / high speed mode Ml or MH. Can be stopped at almost the same position. In other words, in any of the low-speed and high-speed modes Ml and MH, the standard can be satisfied and the ground lifts C and C 'which are almost the same can be secured. Therefore, it is possible to eliminate the deterioration of the crane performance.

Second, a boom having a hook (4) at its tip
(3) a wire rope (3) that is wound down from the tip of (1),
Winch (22) that can be switched to low-speed / high-speed mode (ML, MH) to wind and unwind wire rope (3)
Mode switching means (21), which is switched to one of the low-speed and high-speed modes (ML, MH), and at the start of stoppage of the rotation of the winch (22) to prevent the wire rope (3) from being overwound. (A) a hook (4) having a hook (4) which is located below a tip of a boom (1) and has a predetermined first position;
A first stop start signal detecting means (5) for detecting when the position is closer to the tip than the position (6) and generating a first stop start signal (SL) at the time of the detection; and (b) a hook (4) Is a predetermined second position farther from the tip of the boom (1) than the first position (6)
A second stop start signal detecting means (10) for detecting a position closer to the tip than (11) and generating a second stop start signal (SH) at the time of this detection; and (c) first and second stop signals. Stop start signal detection means
(5, 10), electrically connected to the mode switching means (21) and the winch (22), and (c1) when the switching signal from the mode switching means (21) is the low speed mode (ML), The input of the first stop start signal (SL) from the stop start signal detecting means (5) is monitored. (C2) If the switching signal from the mode switching means (21) is the high-speed mode (MH), the second Stop start signal detection means
Monitor the input of the second stop start signal (SH) from (10), and (c3)
When the first or second stop start signal (SL, SH) to be monitored is input, a signal (S) for stopping the rotation of the winch (22) is input.
A determination means (20) for inputting 1) to the winch (22).

According to the second configuration, the following effect is obtained in addition to the effect of the first configuration. The input signal to the winch 22 in the first configuration is the signal S1 for stopping the rotation of the winch 22 in the low-speed mode Ml, but in the high-speed mode MH, the rotation speed of the winch 22 is reduced to the normal speed in the low-speed mode Ml. This is the signal S2 that goes down to On the other hand, the input signal to the winch 22 in the second configuration is the signal S1 for stopping the rotation of the winch 22 in any of the low-speed / high-speed modes Ml and MH. Therefore, according to the second configuration, the ground lifts C and C ′ can be made higher than in the first configuration.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a crane wire rope winding prevention device according to the present invention will be described with reference to FIGS.
This will be described in detail with reference to FIG.

FIG. 1 is a block diagram of the first embodiment. A hook 4 is attached to a tip of a wire rope 3 wound around a load sheave 2 attached to a tip of a boom 1. A first switch 5 is attached near the load sheave 2 and a first weight 6 is movably engaged with the wire rope 3 at a position at a predetermined interval A below the lower end of the boom 1. Has been established. The switch 5 connects the weight 6 to the first connecting rope 7
a. That is, if the winding becomes excessive in the low speed mode ML, the hook 4 pushes up the weight 6 to loosen the connecting rope 7a. Then, the switch 5 is operated to output a winding prevention signal SL (that is, a stop start signal SL).
The weight 6 is the hook 4 at the maximum speed in the low speed mode ML.
It is disposed at a position where a distance B satisfying the standard can be secured even if it is wound up and stopped.

In contrast to the above configuration, the first embodiment further includes a weight 6
A second switch 10 is attached to the wire rope 3, and a second weight 11 is movably engaged with the wire rope 3 at a predetermined distance D below the weight 6. The weight 11 is the second switch 10
Is suspended by a second connecting rope 7b. That is, in the high-speed mode MH, the hook 4 pushes up the weight 11 to loosen the connecting rope 7b. Then, the switch 10 operates to output the low speed switching signal SH. The weight 11 is arranged at a position where the distance B satisfying the standard can be secured even if the weight 11 winds up the hook 4 at the high speed of the high speed mode MH and is stopped by the weight 6 and the switch 5 after switching to the low speed.

FIG. 2 is a control block diagram of the first embodiment. The control device 20 including a microcomputer or the like includes switches 5, 1
0, is electrically connected to the mode changeover switch 21 and the winch 22. The operation will be described below with reference to FIGS. When the operator sets the low speed mode ML by the mode changeover switch 21, the control device 20 receives this,
The input of the low-speed switching signal SH from the switch 10 is ignored, and the presence or absence of the stop start signal SL from the switch 5 is monitored. That is, when the winch 22 winds the wire rope 3 at a normal speed, the hook 4 hits the weight 11 and pushes it up, and the weight 11 hits the weight 6 and pushes it up.
The switch 5 is actuated and the stop signal SL is sent to the control device 20.
Enter The control device 20 receives the stop start signal SL and sends a signal S1 for stopping the rotation of the winch 22 to the winch 2
2 to stop the winch 22.

On the other hand, the operator operates the mode changeover switch 2
When the mode is switched from the low-speed mode ML to the high-speed mode MH by 1, the control device 20 receives this, and monitors the presence or absence of the stop start signal SL from the switch 5 and the low-speed switching signal SH from the switch 10. That is, when the winch 22 winds the wire rope 3 at a high speed and the hook 4 hits the weight 11 and pushes it up, the switch 10 operates to input a low speed switching signal SH to the control device 20. The control device 20 receives the switching signal SH for low speed and
A signal S2 for switching the rotation speed of the winch 22 to the normal rotation speed in the low-speed mode ML is input to the winch 22, and the rotation speed of the winch 22 is switched to the normal rotation speed in the low-speed mode ML. When the wire rope 3 is further entangled, the weight 11 hits the weight 6 and pushes it up in the same manner as in the low-speed mode ML, the switch 5 is operated, and the stop start signal SL is input to the control device 20. The control device 20 receives the stop start signal SL and inputs a signal S1 for stopping the rotation of the winch 22 to the winch 22 to stop the winch 22.

According to the first embodiment, the stop position of the hook 4 is the position at which the predetermined interval B is secured from the lower end of the boom 1 in both the low speed mode and the high speed mode Ml and MH. Therefore, the same ground lifts C and C 'can be secured in both the low speed mode and the high speed mode Ml.

FIG. 3 is a block diagram of the second embodiment. The control blocks of the second embodiment are the same as those of the first embodiment shown in FIG. The differences are as follows. The same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.
As shown in FIG. 3, in the second embodiment, the switch 10 is attached to the boom 1 adjacent to the switch 5, the weight 11 is disposed below the weight 6 at a predetermined interval D, and the weight is attached to the switch 10. 11 was hung by the third connecting rope 7c. The operation and effect of the second embodiment are almost the same as those of the first embodiment. Therefore, a duplicate description is omitted. In addition, if comprised in this way, breakage of the switch 10 can be prevented.

FIG. 4 is a control block diagram of the third embodiment, and FIG.
FIG. 4 is a side view of the crane 40 in the working posture. As shown in FIGS. 4 and 5, the control device 20 stores in advance the distance A + D (which is a constant) from the lower surface of the tip of the boom 1 to the corresponding position of the weight 11 in the first and second embodiments, The boom 1 is electrically connected to a boom length detector 31 for detecting the extension length Lb of the boom 1, a wire rope length detector 33 for detecting the extended wire rope length Lw, a mode switch 21 and a winch 22. .

That is, the control device 20 operates as follows.
The controller 20 receives the extension length Lb of the boom 1 from the boom length detector 31, the wire rope length Lw from the wire rope length detector 33, and the mode switch 21.
Receives the signal of the low speed mode ML or the high speed mode MH. When the input signal from the mode changeover switch 21 is in the high-speed mode MH when the wire rope 3 is wound, the controller 20 sets the wire rope length Lw to "L".
b + A + D ", the signal S2 for switching the rotation speed of the winch 22 to the normal rotation speed in the low-speed mode ML.
Is input to the winch 22, and the rotation speed of the winch 22 is switched to the normal rotation speed in the low speed mode ML. In the low-speed mode ML, when the hook 4 hits the weight 6 and pushes it up, the switch 5 operates to input a stop start signal SL to the control device 20. The control device 20 receives the stop start signal SL and outputs a signal S1 for stopping the rotation of the winch 22.
Is input to the winch 22, and the winch 22 is stopped.

In the third embodiment, the weight 6 and the switch 5 are eliminated, and the control device 20 is replaced with the weight 6 in the first and second embodiments from the lower surface of the tip of the boom 1.
The distance A (which is a constant) to the corresponding position of is also stored in advance,
In the low speed mode ML, when the wire rope length Lw becomes "Lb + A", a signal S1 for stopping the rotation of the winch 22 is input to the winch 22, and the winch 22 is turned on.
May be stopped.

The configuration and operation of the control device 20 will be described in order to make the description easier, the elevation angle θ of the boom 1 is fixed, and the installation position of the winch 22 and the starting position of the boom 1 are the same. This is the description of the case. However, in practice, the above “Lb + A” and “Lb + A + D” cannot be simply applied by only the extension length Lb of the boom 1 from the boom length detector 31 depending on the installation position of the load sheave 2 or the winch 22. However, since the installation position of the load sheave 2 and the winch 22 is a fixed position with respect to the boom 1, the length is determined with respect to the extension length Lb of the boom 1 (not shown, but the determined length is referred to as “constant length”). E "). Therefore, in such a crane 40, in the control device 20, these fixed lengths E
Is also stored in advance, and the boom 1
Is corrected by this constant length.
However, when the elevation angle θ of the boom 1 changes, these constant lengths E also slightly change. For example, the winding angle (that is, the winding length) of the wire rope 3 in the load sheave 2
Changes depending on the elevation angle θ of the boom 1. Therefore, FIG.
Is omitted in the above description, but is electrically connected also to a boom angle detector 32 for detecting the elevation angle θ of the boom 1 as shown in FIG. . Then, the control device 20 determines the constant length E (consequently, the extension length L of the boom 1 based on the elevation angle θ of the boom 1).
b) is corrected. In any case, the above-mentioned “Lb + A” and “Lb + A + D” are basic, and for various specifications that differ depending on the crane 40, the extension length Lb of the boom 1 input to the control device 20 is controlled as described above. The correction is performed in the device 20.

According to the third embodiment, the first and second embodiments
An effect similar to that of the embodiment is obtained. In the third embodiment, the stop start signal detecting means, the low speed switching signal detecting means, and the judging means described in the claims are the control device 20, the boom length detector 31, and the wire rope length detecting device. The fact that they are collectively configured by the unit 32 does not require explanation.

A fourth embodiment will be described. The following elements in the first to third embodiments may be read and replaced as follows. That is, the "winding prevention signal SL (that is, the stop start signal SL
)) Is read as "first winding prevention signal SL (that is, first stop start signal SL)", and "low speed switching signal SH" is replaced with "second winding prevention signal SL (that is, second stop start signal SL)." ) ", Whereby the control device 20 may have the following operation program.

That is, in the first and second embodiments, when the control device 20 receives the low-speed mode ML from the mode changeover switch 21, the control device 20 ignores the input of the second stop start signal SH from the switch 10, and The presence or absence of the first stop start signal SL is monitored. That is, when the winch 22 winds the wire rope 3 at a normal speed, the hook 4 hits the weight 11 and pushes it up, and the weight 11 hits the weight 6 and pushes it up. The switch 5 is operated and the first stop start signal is sent to the control device 20. Enter SL. The control device 20 is the first
In response to the stop start signal SL, a signal S1 for stopping the rotation of the winch 22 is input to the winch 22, and the winch 22 is stopped. On the other hand, when the control device 20 receives the high-speed mode ML from the mode changeover switch 21, it monitors the presence or absence of the first stop start signal SL from the switch 10. In this case, the control device 20 may or may not ignore the first stop start signal SL from the switch 5. That is, the winch 22 winds the wire rope 3 at high speed and the hook 4
When it hits the weight 11 and pushes it up, the switch 10
Operates to input the second stop start signal SH to the control device 20. The control device 20 receives the second stop start signal SH and outputs a signal S1 for stopping the rotation of the winch 22 to the winch 22.
And the winch 22 is stopped.

According to the fourth embodiment, the stop position of the hook 4 is a position at which the predetermined interval B is secured from the lower end of the boom 1 in both the low speed mode and the high speed mode MH. . Therefore, as in the first and second embodiments, the same ground lifts C and C 'can be secured regardless of the low speed / high speed modes Ml and MH.

The signal input to the winch 22 by the control device 20 in the first and second embodiments is the signal S1 for stopping the rotation of the winch 22 in the low-speed mode Ml, but is used in the high-speed mode MH. 22 rotation speed in low speed mode M
A signal S2 for switching to a normal rotation speed at L and a signal S1 for stopping the rotation of the winch 22 only when the weight 11 pushes up the weight 6 are input to the winch 22. That is, the distance D in the first and second embodiments is a decelerable distance for shifting from the high speed mode MH to the low speed mode Ml. On the other hand, the control device 20 in the fourth embodiment
The signal input to the winch 22 is the low-speed / high-speed mode M
The signal S1 for stopping the rotation of the winch 22 regardless of l or MH. Therefore, the distance D in the fourth embodiment can be shorter than the distance D in the first and second embodiments. That is, the ground heads C and C 'in the fourth embodiment are higher than the ground heads C and C' in the first and second embodiments.

It should be noted that the control device 20 in the third embodiment also stores the operation program of the fourth embodiment and can operate on the basis of the program, and that the same effects as in the fourth embodiment can be obtained. Nor.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment.

FIG. 2 is a control block diagram of the first embodiment.

FIG. 3 is a diagram showing a second embodiment.

FIG. 4 is a control block diagram of a third embodiment.

FIG. 5 is a side view of a crane in a working posture for explaining control of a third embodiment.

FIG. 6 is a side view of a wire rope overwind prevention device of a conventional crane.

FIG. 7 is an explanatory diagram of a hook stopped state in FIG. 6;

[Explanation of symbols]

1 ... boom, 2 ... road sheave, 3 ... wire rope, 4
... Hook, 5 ... First switch (stop start signal detecting means, first stop start signal detecting means), 6 ... First weight (1st stop
Position), 10 ... second switch (low-speed switching signal detecting means, second stop start signal detecting means), 11 ... second weight (second position), 20 ... control device (judging means), 21 ... mode switching Switch (mode switching means), 22 ... winch, M
L: low speed mode, MH: high speed mode, S1: winch stop start signal, S2: winch low speed switching signal.

Claims (2)

[Claims] 1. A wire rope (3) having a hook (4) at its tip and being wound down from the tip of a boom (1);
A winch (22) that can be switched to the high-speed mode (ML, MH) and winds or unwinds the wire rope (3), and a mode switching means that switches between the low-speed and high-speed modes (ML, MH). (21) and a crane wire rope overwind prevention device having a stop start signal detecting means for detecting when the winch (22) stops rotating in order to prevent the wire rope (3) from being overwound. (a) The hook (4) is at a predetermined first position (6) below the tip of the boom (1).
Stop start signal detecting means (5) for detecting when the position is closer to the tip end and generating a stop start signal (SL) upon this detection
(B) detecting when the hook (4) is positioned closer to the tip than a predetermined second position (11) farther from the tip of the boom (1) than the first position (6), A low-speed switching signal detecting means (10) for generating a low-speed switching signal (SH) upon this detection;
(c) Stop start signal detection means (5), low speed switching signal detection means
(10) electrically connected to the mode switching means (21) and the winch (22), and (c1) a stop start signal detecting means when the switching signal from the mode switching means (21) is the low speed mode (ML).
Monitor the input of the stop start signal (SL) from (5), and when the stop start signal (SL) to be monitored is input, winch (22)
Input the signal (S1) to stop the rotation of the winch (22),
(c2) On the other hand, when the switching signal from the mode switching means (21) is the high-speed mode (MH), the stop start signal detecting means (5)
From the input of the stop start signal (SL) from the input and the input of the low speed switching signal (SH) from the low speed switching signal detecting means (10), and the low speed switching signal (SH) to be monitored. Signal (S2) to switch the rotation of the winch (22) to low speed
When the stop start signal (SL) is input, winch (2
A device for preventing winding of a wire rope of a crane, comprising: judgment means (20) for inputting a signal (S1) for stopping rotation of 2) to a winch (22). 2. A wire rope (3) having a hook (4) at its tip and being wound down from the tip of a boom (1),
A winch (22) that can be switched to the high-speed mode (ML, MH) and winds or unwinds the wire rope (3), and a mode switching means that switches between the low-speed and high-speed modes (ML, MH). (21) and a crane wire rope overwind prevention device having a stop start signal detecting means for detecting when the winch (22) stops rotating in order to prevent the wire rope (3) from being overwound. (a) The hook (4) is at a predetermined first position (6) below the tip of the boom (1).
A first stop start signal detecting means (5) for generating a first stop start signal (SL) at the time of detection, and (b) a hook (4) comprising: (6) is detected at a position closer to the distal end than a predetermined second position (11) farther from the distal end of the boom (1).
Second stop start signal detecting means for generating a stop start signal (SH)
(10), (c) first and second stop start signal detecting means (5, 10),
(C1) when the switching signal from the mode switching means (21) is the low-speed mode (ML), the first stop start signal detecting means is connected to the mode switching means (21) and the winch (22).
Monitor the input of the first stop start signal (SL) from (5) and (c2)
The switching signal from the mode switching means (21) is in high-speed mode
(MH), monitor the input of the second stop start signal (SH) from the second stop start signal detecting means (10), and (c3) monitor the first or second stop start signal ( (SL, SH) is inputted, and a judgment means (20) for inputting a signal (S1) for stopping rotation of the winch (22) to the winch (22) is provided. Prevention device.