JPH09175783A - Overwinding prevention device of crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the safety of a work, in the excess winding prevention device of a crane provided with the position detection mechanism of a hook by a weight. SOLUTION: In the overwinding prevention device of a crane, having a weight 5 hung on a limit switch 7 inserted in a wind up rope 2, which can operate a warning circuit 8 and an automatic stop circuit 9 after detecting the bring up of the weight 5 by the ascending of a hook 3 by a limit switch 7, a slant movable piece 11 is installed on the boom 1 side slant-movably and arranged to the upper position of the weight 5 while separating so as not to be contacted with the wind up rope 2. Thereby, the limit switch 13 arranged on the boom 1 side is push-pressed and when the slant movable piece 11 is moved slantly by the ascending of the hook 3, the limit switch 13 is closed by the release of the push-press and the warning circuit 14 and automatic stop circuit 15 are operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hoisting rope, which is vertically slidably inserted into a hoisting rope and is hung at a predetermined position, by lifting a load attachment such as a hanging hook provided on the hoisting rope. The present invention relates to a crane over-winding preventive device which detects that a hanging load is attached and operates a safety device to prevent the hoist load attachment from being excessively hoisted.

[0002]

2. Description of the Related Art A crane winds and hoists a hoisting rope wound around a boom with a winch for lifting a hoisting load, and vertically transfers a hoisting load attached to the rope. In this way, when the hoisting load is transferred, if the hoisting rope is wound up and the hoisting load is transferred upward, if the hoisting rope is excessively wound up, the hoisting load attachment such as a hook provided on the hoisting rope will be attached. It is dangerous because it collides with the top of the boom and pulls the boom backward. For this reason, in the past, cranes have so-called overruns that detect the excessive lifting of the hanging load attachment device and activate the safety device such as an automatic stop device and an alarm device that stops the winch for lifting the lifting load. A device called a winding prevention device was provided. What has been conventionally used as a device for preventing over-winding of this crane is one that uses a position detection mechanism of a hanging load attachment by a weight, for example, a weight having a hoisting rope insertion hole in the center, It was inserted into the hoisting rope so that it could move up and down, and it was hung with a weight detecting means such as a rope on the tension detecting means such as a limit switch, and the hanging load attachment such as a hook provided on the hoisting rope was excessively wound up. At this time, it is possible to detect that the weight is lifted by the lifting of the hanging load attachment. In this way, when the weight is lifted by the lifting of a hanging load attachment such as a hook, the tension of the weight hanging means such as a rope changes. Therefore, the change in the tension is detected by the tension detecting means such as a limit switch and the safety device. By operating the above, it is possible to prevent the hanging load fixture from colliding with the boom top. Since the operating position for operating the safety device to prevent excessive hoisting of the hanging load attachment is stipulated by law, the crane overload prevention device requires the hoisting position of the hanging load attachment to be stipulated by law. It must be able to be detected accurately according to what you do. The over-winding prevention device for a crane, which has been equipped with a mechanism for detecting the position of a suspended load attachment using a weight that has been used so far, makes it easy to adjust the operating position of the safety device simply by adjusting the length of the weight suspension means such as a rope. Since it can be adjusted to suit the legal requirements, and its structure is simple, it was extremely simple and had excellent features in this respect.

[0003]

However, this conventional overwinding preventing device for a crane has such features, but on the other hand, adopts a structure in which the weight is hung by a weight hanging means such as a rope. As a result, the weight hanging means, the weight hanging on the weight hanging means, and the hoisting rope are entangled with each other, which may cause a problem that the hoisting position of the hanging load fixture cannot be detected. That is, when the hoisting rope is wound up and the suspended load is transferred upward, when the hoisting rope rotates together with the suspended load so as to twist about the vertical line as a rotation axis, the weight and the weight suspending means are entangled with each other. Sometimes.
When such a situation occurs, the weight hanging means such as a rope keeps the tension detecting means such as the limit switch always pulled, or sometimes the tension detecting means is given excessive tension to cause damage. In some cases, it may not be possible to detect excessive hoisting of the hanging load fixture. In order to cope with such a problem, a conventional overwinding prevention device for a crane has been disclosed in, for example, Japanese Utility Model Laid-Open No. 61-163291.
A proposal has been made to adopt a position detection mechanism for another type of hanging load attachment that does not rely on a weight, but when such a mechanism is adopted, the above-mentioned "position of safety device" originally possessed by the position detection mechanism based on a weight is originally proposed. The excellent feature of "the operating position can be adjusted easily" will be lost. Therefore, at present, it is basically desirable for the crane over-winding prevention device to be provided with a position detection mechanism using a weight that has been commonly used until now. It is rational to overcome.

The present invention has been made on the basis of the recognition of such a conventional technique, and an object thereof is to prevent an overwinding of a crane provided with a position detecting mechanism of a hanging load attachment by a weight which has been conventionally used. An object of the present invention is to provide a crane over-winding prevention device that can ensure work safety even when it is not possible to detect excessive hoisting of a hanging load attachment due to a failure of the device.

[0005]

The above objects of the present invention are as follows:
“Having a weight that is hung from the boom side and inserted so that it can move up and down with respect to the hoisting rope wound around the boom,
When the hanging load attachment provided on the hoisting rope is excessively wound up, it detects that the weight is lifted by the lifting of the hanging load attachment and activates the safety device to prevent excessive lifting of the hanging load attachment. In the over-winding prevention device for a crane configured to prevent, by detecting a tilting piece that can be tilted by raising the hanging load attachment to a predetermined position and that the tilting piece tilts, A tilting motion detecting means for activating a safety device for preventing excessive hoisting of the hanging load fixture is attached, and the tilting piece is tiltably attached to the boom side, and is located above the weight.
The tilting movement detecting means is arranged on the boom side while being arranged so as not to come into contact with the hoisting rope, and the tilting movement detecting means is arranged on the boom side. " Achieved by the crane over-winding prevention device as it is.

Since the overwinding preventing device for a crane according to the present invention has such a structure, when the hoisting rope is wound up and the suspended load is transferred upward, the weight and the like are suspended from the hoisting rope. If the hoisting position of the hanging load fixture cannot be detected by the position detecting mechanism of the hanging load fixture due to the weight due to entanglement or the like, the hanging load fixture is wound up above the hanging position of the weight. However, the tilting piece detects the tilting movement of the tilting piece because the tilting piece makes a tilting movement due to the lifting of the hanging load attachment. By operating the safety device, it is possible to prevent the hanging fixture from colliding with the boom top.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be clarified by describing concrete examples showing how the present invention is actually embodied with reference to FIGS. 1 and 2. To do. FIG. 1 is a side view showing an overwinding prevention device for a crane according to an embodiment of the present invention, and FIG. 2 is a front view of the overwinding prevention device for a crane shown in FIG.

In FIGS. 1 and 2, 1 is a hoisting boom provided at the front of a crane body (not shown), and 2 is a point sheave 4 provided at the top of the boom 1.
A hoisting rope made of wire for hanging a hanging load, which is wound around the boom 1 via the hook 3, and a hook as a hanging load fixture for hanging a hanging load provided at a lower end portion of the hoisting rope 2. Is. The boom 1 can be erected at a predetermined angle by winding a hoisting rope (not shown) connected to the boom 1 with a winch (not shown). The hoisting rope 2 is a winch (not shown) for raising and lowering a suspended load, and by winding or unwinding it, the suspended load hooked on the hook 3 can be transferred up and down.

Reference numeral 5 is a doughnut-shaped weight having a hoisting rope insertion hole for inserting the hoisting rope 2 in the center, 6 is a hanging rope for hanging the weight 5 for hanging the weight 5, 7
Is a limit switch for activating the alarm circuit 8 and the automatic stop circuit 9, which is arranged on the side of the boom 1 and is connected in parallel to each other to supply current to the alarm circuit 8 and the automatic stop circuit 9 and these circuits 8 and 9. The contact of the switch is connected to the power source 10 of the switch. The weight 5 is inserted so as to be able to move up and down with respect to the hoisting rope 2, and is hung on the contact drive section of the limit switch 7 using a hanging rope 6 for hanging the weight. Thus, the limit switch 7 opens its contact. Since the weight 5 is inserted so as to be able to move up and down with respect to the hoisting rope 2, when the hook 3 provided on the hoisting rope 2 is excessively wound up, it is lifted by the hook 3. As a result, the tension of the rope 6 acting on the limit switch 7 due to the suspension of the weight 5 until now does not act, so that the limit switch 7 closes the contact of the switch and the hook 3 The alarm circuit 8 and the automatic stop circuit 9 as a safety device for preventing excessive winding are activated. In the overwinding prevention device of this embodiment, as described above, the position detecting mechanism of the suspended load attachment by the weight is provided so that the weight 5 is lifted by the hook 3 as in the conventional device. Since the limit switch 7 serving as the tension detecting means detects that the hook 3 is lifted up and activates the safety device, it is possible to prevent the hook 3 from being excessively wound up as long as it functions normally. In the present embodiment, the weight 5 is hung by a hanging rope 6 for hanging the weight directly on the contact drive section of the limit switch 7. Detecting excessive hoisting of the hanging load attachment by hanging the weight from the boom side so that changes in the tension of the weight hanging means act on tension detectors such as limit switches. You can

The construction of the over-winding prevention device for a crane according to the present embodiment described above is the same as that of the over-winding prevention device which has been commonly used until now. The configuration of the example will be described. Reference numeral 11 is a tilting piece pivotally supported on the boom 1 by a pin 12, and 13 is a limit switch similar to the limit switch 7 for operating the alarm circuit 14 and the automatic stop circuit 15, and like the limit switch 7, The alarm circuit 14 and the automatic stop circuit 15 arranged on the boom 1 side and connected in parallel with each other
The contact of the switch is connected between the power supply 16 and the power supply 16 for supplying current to these circuits 14 and 15. The tilting piece 11 is formed of a lever-shaped weight and is used for the hoisting rope 2
The tip on the side is pivotally supported by the boom 1 so as to be urged downward by its own weight, and the tip on the side of the boom 1 is arranged to press the contact drive section below the limit switch 13. The limit switch 13 opens its contact in this state. In addition, the tilting piece 11 is arranged in the upper part of the weight 5 so as not to come into contact with the hoisting rope 2 as shown in FIG. When 3 is rolled up and rises above that portion, the rise makes it possible to contact the hook 3 or its accessory and perform a tilting motion. When the hook 3 moves up to a predetermined position, the tilting piece 11
When the tilting operation is performed, the pressing force from the tilting piece 11, which has been acting on the limit switch 13 until now, ceases to act, so the limit switch 13 closes the contact of the switch, and the alarm circuit 14 and the automatic stop circuit. 15
Activate That is, the limit switch 13 holds the tilting piece 11 in an immovable state when the tilting piece 11 is not tilted and holds the tilting piece 11 in a non-contact state when the tilting piece 11 is tilted. The contacts are switched and the safety device is activated. Therefore, the limit switch 13 detects the tilting motion of the tilting piece 11 to activate the safety device.
It functions as a detecting means of the tilting movement of the.

The overwinding prevention device for a crane according to this embodiment is
Since the hoisting rope 2 is wound up and the suspended load is transferred upward due to the troubles such as the hoisting rope 6 or the weight 7 and the hoisting rope 2 being entangled, the hoisting rope 2 has a structure as described above. When the winding position of No. 3 cannot be detected by the hook position detection mechanism using the weight, the hook 3 moves to the weight 7
It was rolled up above the hanging position of, and eventually,
Although the tilting piece 11 tries to move upward to a position higher than the tilting piece 11, the tilting piece 11 tilts due to the lifting of the hook 3. Therefore, the limit switch 13 is closed to cause the alarm circuit 1 to move.
4 and the automatic stop circuit 15 are activated, and the hook 3 is prevented from colliding with the top of the boom 1.

Therefore, according to this embodiment, in the overwinding preventive device for a crane provided with a hook position detecting mechanism using a weight, which has been conventionally used, it is possible to detect excessive hoisting of the hook 3 due to its failure or the like. Even if it is no longer possible, the safety of crane work can be secured.
In other words, the safety of work can be ensured while making the most of the excellent feature that "the operating position of the safety device can be easily adjusted" that is originally provided in the overwinding prevention device for cranes using weights that has been commonly used. The practically excellent crane overwinding prevention device can be obtained with a simple configuration. Further, the tilting piece 11 is arranged particularly apart from the hoisting rope 2 so as not to come into contact with the hoisting rope 2, and is arranged especially above the weight 5 which is a portion relatively close to the top of the boom 2. Therefore, there is almost no risk of being impacted by the swing of the hoisting rope 2 caused by the swing of the suspended load or the like.

In this embodiment, the mitt switch 13, which serves as a tilting motion detecting means of the tilting piece 11, releases the pressing by the tilting piece 11 when the tilting piece 11 tilts due to the lifting of the hook 3. Although the safety device is operated by doing so, when the tilting piece 11 tilts, the safety device may be operated by pressing the tilting piece 11 on the contrary. Any tilting motion detecting means for activating the safety device by detecting that the tilting motion is performed may be used. The alarm circuit 14 and the automatic stop circuit 15 which are safety devices operated by the limit switch 13 are separate from the safety device operated by the limit switch 7 which detects that the weight 5 is lifted in this embodiment. Although provided, it may be used also as a safety device operated by the limit switch 7.

[0014]

As is apparent from the above description, the present invention relates to a crane over-winding prevention device provided with a mechanism for detecting the position of a hanging load fixture by a weight, and in particular, "a predetermined position of the hanging load fixture. A tilting piece that can be tilted by ascending to an angle and a tilting operation that activates a safety device to prevent excessive hoisting of the hanging load fixture by detecting that the tilting piece tilts. The tilting piece is attached to the boom side so as to be tiltable, and the tilting piece is arranged at a position above the weight so as not to come into contact with the hoisting rope. Since the detection means is arranged on the boom side, it is excellent that "the operating position of the safety device can be easily adjusted" that is originally included in the crane overwinding prevention device using a weight that has been commonly used so far. While it taking advantage of the long, over-winding prevention apparatus practically excellent crane is obtained with a simple configuration that can ensure the safety of the work. Further, the tilting piece is unlikely to be impacted by the swing of the hoisting rope or the like caused by the swing of the suspended load or the like.

[Brief description of the drawings]

FIG. 1 is a side view showing an overwinding prevention device for a crane according to an embodiment of the present invention.

FIG. 2 is a front view of an overwinding prevention device for the crane of FIG.

[Explanation of symbols]

 1 boom 2 hoisting rope 3 hook 4 point sheave 5 weight 6 suspension rope for hanging weight 7 limit switch 8 alarm circuit 9 automatic stop circuit 10 power supply 11 tilting piece 12 pin 13 limit switch 14 alarm circuit 15 automatic stop circuit 16 power supplies

Claims (4)

[Claims] 1. A hoisting load attachment provided on the hoisting rope is excessive, having a weight that is inserted through the hoisting rope around the boom so that the hoisting rope can be moved up and down and is hung from the boom side. When hoisted, in a crane overwinding prevention device that detects that the weight is lifted by the lifting of the hanging load attachment and activates the safety device to prevent excessive lifting of the hanging load attachment, To prevent excessive hoisting of the hanging load fixture by detecting a tilting piece that can be tilted by raising the hanging load fixture to a predetermined position and detecting the tilting movement of the tilting piece. A tilting motion detecting means for activating a safety device is additionally provided, the tilting piece is tiltably attached to the boom side, and is arranged above the weight so as not to come into contact with the hoisting rope. If you do In addition, an overwinding prevention device for a crane, characterized in that the tilting motion detecting means is arranged on the boom side. 2. A safety device to be operated by the tilting movement detecting means is provided separately from a safety device to detect and operate when the weight is lifted by lifting of the hanging load attachment. The over-winding prevention device for a crane according to claim 1. 3. The safety device operated by the tilting movement detecting means is also used as a safety device which detects and operates the lifting of the weight by the lifting of the hanging load attachment. Over-winding prevention device for crane 1. 4. When the tilting piece is not tilted, the tilting piece is brought into contact with the tilting piece to hold the tilting piece in an immovable state, and when the tilting piece is tilted, the tilting piece is not in contact with the tilting piece. A limit switch whose contacts are switched is used, and the over-winding prevention device for a crane according to claim 1, claim 2 or claim 3, is used.