JP2000185897A - Over-reelout preventing device for winch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent over-reelout and any accident, by comparing a radial distance from each antenna to the surface of the outermost layer of a winding rope with a winding radius from each antenna to the rope surface of the outermost layer of a dead winding layer of a winding rope for regulating slip, and by stopping a drum when the both are matched with each other. SOLUTION: The following cases are uniquely judged as over-reelout cases: a case that a winding distance L2 of a drum 1 is compared with a distance L3 from each antenna of the drum 1 to the rope surface of the outermost layer of a dead winding layer of a winding rope 5 and the both are coincided with each other; and a case that the distance L2 to the rope surface of the outermost layer of the winding rope wound about the drum is longer than the distance L3 to the rope surface of the outermost layer of the dead winding layer of the winding rope by a prescribed length. At this time, current carrying of a solenoid valve is cut off to regulate the over-reelout of a winch. The distance L2 from each antenna to the rope surface of the outermost layer of the winding rope 5 wound about the drum 1 can be accurately detected by calculation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winch for loading and unloading a hoisting rope, and more particularly to measuring a distance from a radially outer side of a winding drum to an outermost layer of the winding drum. The present invention relates to a winch overextending prevention device configured to stop the winding drum based on the distance measurement value.

[0002]

2. Description of the Related Art This type of conventional winch device has a winding drum,
The winding drum diameter is set to several times to several tens times the nominal outer shape of the hoisting rope to be used in order to prevent damage due to fatigue of the hoisting rope, and the winding rope is wound around the winding drum in multiple layers and fed out. ing. Attachment of the hoisting rope to the winding drum is performed by first inserting the hook of the hoisting rope into the winding drum through a small opening extending appropriately from one end of the winding drum toward the other end, and inserting the hook into the winding drum inner surface. It fits into the L-shaped hook fixed to the
In the winding, the first layer is guided by a rope guide groove formed on the outer peripheral surface of the winding drum, and the second and subsequent layers guide the gap between the ropes formed between adjacent wound winding ropes. Wrap as For this reason, a frictional force proportional to the winding angle θ of the hoisting rope is generated between the first layer of the winding drum and the guide groove, and between the respective layers. Slip is regulated and the tension is stabilized. Therefore, when the take-up rope is unwound within the normal unwinding range, the rope does not fall out of the drum, but exceeds the number of windings or the number of windings necessary to prevent the rope from being pulled out (hereinafter, referred to as a discarded winding number or a discarded winding layer). If it is fed out excessively, the frictional force becomes insufficient, and it may come off at once.

For example, when the winch is mounted on the body of a crane and a hook is attached to a hoisting rope and the hook is used for loading and unloading, the rotating shaft of the winch is connected to a hydraulic motor of the body and the hoisting rope is mounted on the crane boom top. Pull out and support it on the sheave of the boom top, attach a hook to the tip of a hanging hoisting rope that hangs in the direction of gravity from the sheave, and perform loading and unloading by lifting and lowering the hook. Is
For safety reasons, the height is set higher than the level ground. Therefore, when the load is unloaded to the unloading area below the crane installation surface and the unwinding reaches the number of discarded windings or discarded winding layers, the frictional force is insufficient at a stretch, and the load falls along with the hoisting rope. become.

[0004] Therefore, it is necessary to detect the number of remaining winding layers of the winding drum and stop the winding drum immediately before the feeding of the winding rope reaches the discarded winding portion of the winding rope to ensure safety. And devices have been proposed.

For example, Japanese Patent Application Laid-Open No. 7-206385 discloses a tip of a swing arm 4 which rotates about a support shaft 3 installed in parallel with a rotation shaft 2 of a winding drum 1 as shown in FIG. A hoisting rope 5 wound around the winding drum 1
The roller 6 is pivotally supported so as to rotate in contact with the outermost layer of the rope, and the oscillating arm 4 is urged toward the bobbin 1 by pushing the oscillating arm 4 toward the outermost layer of the rope 5. A rope winding / unwinding device 8 provided with a spring 7 so as to be brought into contact with and rotated is proposed.

[0006]

The above-mentioned rope winding,
The feeding device 8 obtains the number of remaining winding layers of the hoisting rope of the winding drum 1 based on the amount of displacement of the roller 6 in the radial direction.
As the wear of the roller 6 progresses due to the contact with the hoisting rope 5 made of a wire, it must be replaced as needed.
The abrasion resistance of the roller 6 is determined by using a carbon steel (S4
5C, S55C, SCM, etc.) and can be improved by a predetermined heat treatment. However, if the hardness of the roller exceeds the hardness of the hoisting rope 5,
Wear occurs and the reliability is reduced. Therefore, the roller 6
Has to be set appropriately lower than the strand hardness of the hoisting rope 5 and must be used as a consumable.

When the hoisting rope 5 is wound around the winding drum 1, the swinging arm 4 hinders the winding operation. Therefore, the swinging arm 4 must be turned over and held on the side opposite to the winding drum 1 side. Hoisting rope 5 due to forgetting to return swinging arm 4
There is also a problem that the function of detecting the number of remaining winding layers does not work.

For this reason, a light or ultrasonic type distance measuring device is disposed radially outward of the winding drum 1, and the remaining number of winding layers of the hoisting rope 5 is measured by laser light or ultrasonic wave to perform winding. A method for detecting the number of remaining winding layers of the body 1 has been devised.

However, light cannot be measured due to the presence of light-shielding substances such as rainfall, snowfall, fog, and dirt, and ultrasonic waves cannot be measured due to irregular reflection of sound waves due to rainfall or snowfall, or blowing noise. However, there is a drawback that distance measurement cannot be performed when the wind is strong because the wind is easily swept away.

Therefore, a technique to solve the problem is to detect the number of remaining winding layers of the winding drum 1 without being influenced by the weather conditions and the dirt on the rope surface, and to prevent the overwinding of the winding rope 5 based on the remaining winding number. Therefore, an object of the present invention is to solve the problem.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been proposed to achieve the above object, and is arranged radially outward of a winding drum and wound around the winding drum along the radial direction of the winding drum. A transmitter for irradiating an electromagnetic wave excluding light to the surface of the outermost layer of the wound rope via a transmission antenna, and a transmitter that is juxtaposed with the transmitter and reflects radially outward from the outermost layer surface of the wound rope. And a receiver for receiving the electromagnetic wave through a receiving antenna, and a radial distance from the transmission point of the transmission antenna and the outermost rope surface of the discarded winding layer of the winding rope for regulating slippage from the reception point of the reception antenna. And a transmission point of each antenna based on a time required for the reflected wave to be received by the receiving antenna from the start of irradiation of the electromagnetic wave of the transmitting antenna and a speed of the electromagnetic wave. A calculating means for calculating a radial distance from a point to a surface of an outermost layer of a hoisting rope wound on the winding drum; and an output of the calculating means is inputted, and each antenna which is an output of the calculating means is wound up with each antenna. When the radial distance to the surface of the outermost layer of the rope and the winding radius to the rope surface of the outermost layer of the discarded winding layer of the hoisting rope for regulating the antenna and slip are compared, or When the distance between each antenna and the outermost rope surface of the hoisting rope wound around the winding drum is a predetermined distance longer than the distance between each of the antennas and the outermost rope surface of the discarded winding layer of the hoisting rope, It is an object of the present invention to provide a winch over-extending prevention device comprising: an over-extending restricting unit that outputs a stop signal to a stopping unit that stops the body.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a winch applied to a crane will be described below in detail with reference to FIGS. The same components as in the prior art are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, reference numeral 25 denotes a crane boom, and reference numeral 21 denotes a winch. The rotary shaft 2 of the winch 21 is rotatably supported by a shaft support (not shown) of an upper rotating body of the crane. One end of the rotating shaft 2 has a hydraulic motor 23, a clutch and the like installed on the upper rotating body. Hydraulic motor 23 is connected by a hydraulic pump 24 that is operated by a driving force of an engine (not shown).
It is rotated by the supply of hydraulic oil from.

The hoisting rope 5 is fed out from the winding drum 1 of the winch 21 by a predetermined length, is wound around the guide sheave 29 and the top sheave 26 which are supported by the boom top 25 from above, and moves downward in the direction of gravity. Hanging
Further, after being wound around the multiple sheaves 28 of the hook block 27, it is connected to the boom top 25 via the shackle 30 or the like. An operating hydraulic circuit 31 for driving the hydraulic motor 23 communicates a discharge port 32 of the hydraulic pump 24 with one supply / discharge port 33 of the hydraulic motor 23 through a first conduit 34, and the other of the hydraulic motor 23 A second pipe 37 connects the supply / discharge port 35 with the drain 36, and switches and connects the first pipe 34 and the second pipe 37 to the hydraulic pump 24 and the drain 36. The control switching valve 38 is interposed and configured.

The control switching valve 38 comprises a pilot type three-chamber four-port directional switching valve. By switching the first pilot oil passage 39 and the second pilot oil passage 40, the control switching valve 38 is moved to the neutral position ( From stop) to a winding position and a feeding position (unloading), respectively. Therefore, when the control switching valve 38 is switched to the winding position, the discharge port 32 of the hydraulic pump 24 is connected to the hydraulic motor 2.
3, while the other suction / discharge port 33 of the hydraulic motor 23 is connected to the drain 36 and rotates in the winding direction, and when the hydraulic motor 23 is switched to the feeding position, The other suction / discharge port 3 of the hydraulic motor 23
3, the discharge port 32 of the hydraulic pump 24 communicates with the drain 36, and one suction / discharge port 35 communicates with the drain 36, so that the hydraulic motor 23 rotates in the feeding direction. Of course, in the neutral position, all the hydraulic oil supplied from the hydraulic pump 24 is discharged to the drain 36, and the hydraulic motor 23 is stopped.

The control switching valve 38 is configured to interlock with a switching operation of a switching valve 42 which is interlocked with an operation of an operation lever 41, and the operation lever 41 is installed in the cabin. For this reason, it becomes possible to carry out cargo handling while monitoring the rise and fall of the cargo in the cabin.

On the other hand, the first pilot oil passage 39 communicating one pilot port 43 of the control switching valve 38 with the pilot pump 44 in order to prevent over-travel or the like due to the forced stop of the hydraulic motor 23. Is provided with an electromagnetic valve 46. When the solenoid valve 46 is energized, the first
The upstream and downstream of the pilot oil passage 39 are communicated with each other, and the upstream and downstream of the solenoid valve 46 are shut off by the return force of a spring (not shown) when the power is released. Therefore, when the energization of the solenoid valve 46 is released, the control switching valve 38 returns to the neutral position, all the hydraulic oil supplied from the hydraulic pump 24 is discharged to the drain 36, the motor 23 is stopped, and the winding drum 1 is turned off. Stop. For this reason, if it is configured that the energization of the solenoid valve 46 is automatically cut off by detecting the number of remaining turns of the winding drum 1, the unloading place when the unloading place is below the installation surface of the crane is unloaded. Of the hoisting rope 5 can be prevented, and an accident in which the hoisting rope 5 comes off can be prevented. As a device for detecting the number of remaining turns of the winding drum 1, as described above, it is preferable to detect the distance from the radially outer side of the winding drum 1 to the outermost layer of the winding drum 1 by a non-contact type distance measuring device. .

Therefore, as shown in FIG. 1 and FIG. 2, the transmission is performed with the axis X1 of the winding drum 1 facing outward from the winding drum 1 radially outward and spaced apart from the winding drum 1 by a predetermined distance. So that the electromagnetic wave emitted from the transmitting antenna 49 of the transmitter 47 collides with the outermost layer of the hoisting rope 5 wound around the winding drum 1 in a direction substantially perpendicular to the outermost layer. ,
An electromagnetic wave reflected by the collision with the outermost layer (hereinafter, referred to as a reflected wave) is received by the receiving antenna 50 of the receiver 48. The antenna is wound around the winding drum 1 from the transmission point of the transmission antenna 49 and the reception point of the reception antenna 50 based on the reciprocating time of the electromagnetic wave from the irradiation of the electromagnetic wave to the reception of the reflected wave and the speed of the electromagnetic wave. It is configured to detect a radial distance L2 to the outermost layer of the existing hoisting rope 5.

The transmitter 47 generates a signal internally,
This signal is configured to be emitted from the transmission antenna 49 as an electromagnetic wave, and the irradiation angle of the electromagnetic wave of the transmission antenna 49 is set such that the angle of irradiation of the electromagnetic wave from the radially outside of the winding drum 1 to the surface of the outermost layer of the remaining winding layer of the winding drum 1 On the other hand, the electromagnetic wave is set to be radiated from the outside of the winding drum 1 in the radial direction, and the directivity is at least discarded from the surface of the outermost layer of the wire of the hoisting rope 5 when fully wound around the axis X1 of the winding drum 1. The irradiation range of the electromagnetic wave is set to reach the surface of the outermost layer of the winding layer.

The reception angle of the electromagnetic wave of the receiving antenna 50 is such that the reflected wave reflected radially outward by the outermost layer surface of the remaining winding layer of the winding drum 1 of the winding drum 1 is received radially outward. The directivity is set so as to receive a reflected wave reflected by at least the outermost layer surface of the winding layer 5 from the outermost layer surface of the hoisting rope 5 when fully wound around the axis X1 of the winding drum 1. You.

The receiver 48 includes an amplifier and a detector (both not shown). The amplifier amplifies the signal of the received reflected wave, and the detector combines the reflected wave from the hoisting rope 5 with the amplified signal. Other than that, for example, the reflected wave reflected from the periphery of the flange or the winch is divided into levels by detection so that only the reflected component from the surface of the hoisting rope 5 is recognized based on the difference in the signal level.

The control device 51 is a device for preventing the winding rope from being excessively fed out by de-energizing the electromagnetic valve 46, and is connected to the transmitter 47 and the receiver 48 and the electromagnetic valve 46 by wires. I have.

More specifically, the control device 51 includes a storage unit 5
2. The calculating means 53 and the overrunning restricting means 54, the storing means 52 stores the transmitting point of the transmitting antenna 49 and the distance L3 between the receiving antenna 50 and the rope surface of the outermost layer of the discarded winding layer, The calculation means 53 calculates the time required t from the start of the electromagnetic wave irradiation of the transmission antenna 49 until the reflected wave is received by the reception antenna 50 and the speed v of the electromagnetic wave based on each of the antennas 49 and 5.
0 from the transmission point and the reception point to the surface of the outermost layer of the hoisting rope 5 wound around the winding drum 1.
2, the over-feeding restricting means 54 receives the output of the calculating means 53, and outputs the distance L2 to the outermost rope surface of the hoisting rope 5 wound around each antenna and the winding drum 1. The antennas are compared with the distance L3 from the outermost layer of the rope to the outermost layer of the discarded winding layer, and when they match each other, or the outermost layer of the hoisting rope 5 wound around each of the antennas and the winding drum 1. Distance L to
When a distance 2 is longer than a distance L3 between each antenna and the rope surface of the outermost layer of the discarded winding layer of the hoisting rope 5, a solenoid valve 46 as stopping means for stopping the winding drum 1 is provided.
To output a signal for canceling the energization. In addition, as the electromagnetic wave, a millimeter wave except light, a centimeter wave, a microwave, or the like was used.
The distance can be measured without being affected by fog or the like and irrespective of dirt (oil or oil stain) on the surface of the hoisting rope 5.

Accordingly, when the load of the winch 21 is lowered, the distance L2 between the transmitter 47, the receiver 48, each antenna and the outermost rope surface of the hoisting rope 5 is detected. The emergency stop of the solenoid valve 46 is automatically performed by the device 51, and even if the crane is unintentionally unloaded below the installation surface of the crane, unreeling is restricted regardless of the operator's consciousness, and the hoisting rope is controlled. 5 is regulated. In the present embodiment, the control device 51 includes a CPU, an RO,
M, RAM, I / O, a microcomputer or a sequencer mainly configured with an interrupt circuit, a backup power supply and the like. In this case, the storage means 52 stores the RO
The arithmetic means 53 and the feed stop means are constituted by a CPU by means of M or RAM. The ROM or RAM stores the above-mentioned respective storage devices and a calculation formula which will be described later. The values are read and calculated, and the control of the solenoid valve 46 is executed.

Next, the loading operation will be described.

When the key switch (not shown) of the crane is
When the engine is switched to N and a construction machine engine (not shown) as a power source is started, drive power is supplied to the control device 51 and the solenoid valve 46, respectively, and the hydraulic pump 24 operates, The upstream and downstream of the first pilot oil passage 39 communicate with each other.

When the winch 21 is driven to wind the hoisting rope 5, the operating lever 41 is manually switched to the hoisting position.

Thus, the control switching valve 38
Is switched to the winding position, the rotation of the hydraulic motor 23 rotates the winding drum 1 in the winding direction, and the winding rope 5 is sequentially wound on the winding drum 1.

After the load is placed at a predetermined position in the horizontal plane by turning the upper swing body (not shown) of the crane, the operation lever 41 is switched from the neutral position to the extended position.
Therefore, the control switching valve 38 switches the operating hydraulic circuit 31 to the delivery position. Hydraulic motor 23
Rotates in the unreeling direction, the hoisting rope 5 is unreeled, and the load sequentially descends.

At this time, the outermost layer of the hoisting rope 5 wound around the winding drum 1 is constantly irradiated with electromagnetic waves excluding light from the transmitting antenna 49 of the transmitter 47, and the receiver 48 Receives the reflected wave (electromagnetic wave) by its receiving antenna 50 and inputs the amplified and detected signal to the arithmetic means 53.

At this time, the calculating means 53 stores the value stored in the storing means 52, that is, the transmitting antenna 49.
The distance L3 from the transmission point and the reception point of the reception antenna 50 to the rope surface of the outermost layer of the discarded winding layer has already been read, and first, the electromagnetic wave emitted from the transmission antenna 49 is reflected as a reflected wave from the start of irradiation. From the transmission point of each antenna and the reception point to the outermost layer of the hoisting rope 5 wound around the winding drum 1 based on the time t required for reception by the receiving antenna 50 and the speed v of the electromagnetic wave. Is calculated in the radial direction L2.

For example, from the start of transmission, a hoisting rope 5
The time until the reflected wave reflected by the surface of the outermost layer is received is obtained by the integration of the internal counter, and based on the required time and the speed of the electromagnetic wave, the hoisting rope from the transmitting point and the receiving point of the transmitting antenna 49 is obtained. The radial distance L2 to the outermost layer 55 is calculated backward. The pulse-modulated electromagnetic wave is applied to the outermost layer of the hoisting rope 5 from the radial outside of the winding drum 1, and the time difference between the transmission pulse and the reception pulse, that is, the time required for the electromagnetic wave to return to the target, the speed of the electromagnetic wave, When the radial distance L2 is obtained, when the round-trip time of the electromagnetic wave is t and the speed of the electromagnetic wave is C, the distance L2 can be obtained by Expression (1).

L2 = C · t / 2 (1) Equation (1) is an equation corresponding to the pulse modulation method, and is expressed by FM
In the case of the CW method, the two-frequency CW method, and the spread spectrum method, calculation is performed using the corresponding equations. In addition,
These equations are well known.

Thus, the over-feed control means 54
Compares the distance L2 in the radial direction with the distance L3 from each antenna to the rope surface of the outermost layer of the discarded winding layer, and when they match, the electromagnetic valve 46 as a stopping means for stopping the winding drum 1 Output a signal to cancel the energization
One pilot port 43 of the control switching valve 38
The first pilot oil passage 39 that communicates with the pilot pump 44 is shut off.

As a result, the control switching valve 38 is switched to the neutral position, and all the hydraulic oil supplied from the hydraulic pump 24 is discharged to the drain 36. As a result, an overrun accident is prevented. Of course, it is also possible to advance the timing of releasing the energization of the overwinding restricting means 54 to the electromagnetic valve 46, and to further enhance safety.

That is, in accordance with the inertia of the hydraulic motor 23 used and the variation in the winding state of the hoisting rope 5, the hoisting rope 5
If the distance L2 to the outermost layer of the rope is set shorter than the distance L3 to the outermost layer of the winding layer of the hoisting rope 5, the safety is further improved.

As described above, in the present embodiment, the winding distance L2 of the winding drum 1 and the distance L3 from each antenna of the winding drum 1 to the rope surface of the outermost layer of the discarded winding layer of the hoisting rope 5 are compared. Or when the distance L2 from the outermost layer of the hoisting rope wound around the winding drum to the rope surface is longer than the distance L3 from the outermost layer to the rope surface of the outermost layer of the winding rope. It is determined unambiguously with time, and the energization of the solenoid valve 46 is cut off to restrict over-extension of the winch. Further, since the distance L2 to the outermost rope surface of the hoisting rope 5 wound around each antenna and the winding drum 1 can be accurately detected by the above-described calculation, the antenna is wound around the winding drum 1. Hoisting rope 5
The winding radius L4 up to the rope center line of the outermost layer is calculated, and as shown in FIG. 3, in the vicinity of the collar or the rotation axis of the winding drum, the rotation axis of the collar or the rotation axis of the winding drum can be detected. A drum rotational speed detecting means, for example, a drum rotational speed detecting means 56 comprising a magnetic sensor and a reflector or an LED and a phototransistor is provided to determine the ascending and descending speeds of the hoisting rope 5, and the lifting and lowering of the load is performed based on the rope speed. It is also possible to adjust the speed. Winding radius L4
Is the distance from the axis X1 of the winding drum 1 to each antenna.
1, if the rope diameter is d, it is obtained from equation (2), and the rope speed is obtained from equation (3), where v is the rotation speed of the winding drum 1.

L4 = L1−L2-d / 2 (2) V = 2π · L4 · v (3) When the rope speed V is smoothly adjusted, the hydraulic pump should be used. A variable displacement pump is used, and the flow rate of the motor is controlled by controlling the tilt angle of the variable displacement pump.

Further, since the winding radius L4 of the hoisting rope 5 wound around the drum winding drum 1 up to the center line of the outermost rope can be accurately detected, as shown in FIG. A drum rotation angle detection means, such as a magnetic sensor, a reflector and a rotary encoder, or an LED, a phototransistor and a rotary encoder so as to detect the rotation axis of the collar or the rotation axis of the winding drum near the collar or the rotation axis of the drum. And a change in the winding amount Q1 of the winding drum 1 during operation is determined, and the wire rope 5 is detected based on the change in the winding amount Q1 of the winding drum 1.
It is also possible to accurately determine the amount of unwinding, and to determine the over feeding based on the change in the winding amount Q1. The winding amount Q1 of the winding drum 1 is obtained by detecting the drum rotation angle θ, calculating the winding amount Q at regular intervals by the following equation (4), and integrating the calculated value by an integrator.

Q1 = 2π · L4 · θ (4) Therefore, it is possible to feed out and take up the tension and the speed at a constant speed, and it is possible to meet the needs of crane operation.

In the above embodiment, a warning may be issued when overrun is detected, and the warning of the operator may be used.

Thus, the present invention can be variously modified without departing from the spirit of the present invention, and it is natural that the present invention extends to the modified one.

[0043]

As described in detail in the above embodiment, the present invention makes it possible to accurately detect the change in the radius of the drum of the winding drum. The distance measurement is spaced a predetermined distance radially outward from the winding drum, with the axis of the winding drum facing outward from the radial direction of the winding drum, and arranged side by side with the transmitter and the receiver, from the transmitting antenna of the transmitter. The electromagnetic wave excluding the light to be irradiated is caused to collide with the surface of the outermost layer of the hoisting rope wound on the winding drum, and the reflected wave reflected radially outward by the collision is received by the receiving antenna of the receiver, and The time from the start of electromagnetic wave irradiation until the reflected wave is received, and the outermost layer of the hoisting rope wound around the winding drum from the transmitting point of the transmitting antenna or the receiving point of the receiving antenna based on the speed of the electromagnetic wave. Since the distance is measured by detecting the change in the winding radius of the winding drum to the surface,
This eliminates the need for contact-type replacement work,
The winding radius can be accurately detected irrespective of bad weather such as rainfall, snowfall, and fog, and even indoors, regardless of the dirt on the hoisting rope. Then, after detection, the winding distance is compared with the distance from the axis of the winding drum to the outermost layer of the discarded winding layer of the hoisting rope for restricting slippage, and when the two values match, or When the distance to the outermost rope surface of the hoisting rope wound around the trunk is a predetermined distance longer than the distance to the outermost rope surface of the discarded winding layer of the hoisting rope, a stop signal is sent to the stopping means for stopping the winding drum. Since it is configured to output, it is possible to prevent an overrun and to prevent an accident, regardless of the operator's recognition.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a relationship between a crane and a winch overextending prevention device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a winch, a transmitter, and a receiver according to one embodiment of the present invention.

FIG. 3 is an explanatory view showing an embodiment in which a rope speed detecting means for detecting a rope speed is provided in the winch over-extending prevention device according to the embodiment of the present invention.

FIG. 4 is an explanatory view showing an embodiment in which a rotation angle means is provided for detecting a winch capacity in the winch over-extending prevention device according to the embodiment of the present invention.

FIG. 5 is a main part detailed view showing a conventional device for detecting the number of remaining layers of a winch.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 winding drum 5 hoisting rope 21 winch 46 stopping device 47 transmitter 48 receiver 49 transmitting antenna 50 receiving antenna 52 storage means 53 calculating means 54 overextending restricting means L1 radial distance d nominal outer diameter of hoist rope L2 radial distance L3 Winding radius from the transmitting / receiving antenna to the outermost rope surface of the discarded winding layer L4 Distance from the axis of the winding drum to the outermost rope core of the remaining number of winding layers of the hoisting rope

Claims (1)

[Claims] An electromagnetic wave, excluding light, is transmitted via a transmitting antenna to a surface of an outermost layer of a hoisting rope which is arranged radially outward of the winding drum and is wound around the winding drum along the radial direction of the winding drum. A transmitter for receiving, via a receiving antenna, an electromagnetic wave reflected radially outward from the outermost layer surface of the hoisting rope, and a transmitting point of the transmitting antenna; Storage means for storing in advance the radial distance from the receiving point of the receiving antenna to the outermost rope surface of the discarded winding layer of the hoisting rope for restricting slippage, reflected waves from the start of electromagnetic wave irradiation of the transmitting antenna. The transmission point of each antenna based on the time required for reception by the reception antenna and the speed of the electromagnetic wave, and the diameter from the reception point to the surface of the outermost layer of the hoisting rope wound around the winding drum. Calculating means for calculating the directional distance, the output of the calculating means being input, and the output of the calculating means for regulating the radial distance to the surface of the outermost layer of each of the antennas and the hoisting rope, and for restricting each of the antennas and slipping. Compare the winding radius of the winding rope up to the outermost rope surface of the discarded winding layer, and when they match, or to each antenna and the outermost rope surface of the winding rope wound around the winding drum When the distance of each antenna is longer than a predetermined distance from the distance to the rope surface of the outermost layer of the discarded winding layer of the hoisting rope, there is provided overfeeding restriction means for outputting a stop signal to the stopping means for stopping the winding drum. A device for preventing over-extending of a winch.