JPH07206379A - Method and device for regulating hoist cable of jib crane - Google Patents

Abstract

PURPOSE:To perform simple correction of displacement of two hoist cables through an operation control part even when displacement occurs to a movement amount of a cable, in a crane using the two hoisting cables. CONSTITUTION:In a jib crane having an endless type winder, hoisting cables 9A and 9B of an S-twist and a Z-twist, respectively, are operated by a single winder and the drum shafts of the winder are intercoupled through an electromagnetic clutch for tuning drive. The weight type detecting elements 18a of excessive winding limit switches 18 disposed to the winding cables 9A and 9B at the tip of a jib 5 are operated by switch operation pieces 19 attached to the tips of the hoisting cables 9A and 9B, respectively. Further, simultaneously with the stop of drive of the winder side more rapid by an amount equivalent to an operation difference between the excessive winding limit switches 18 by the respective switch operation pieces 19, coupling by an electromagnetic clutch is disconnected. Until operation of the other excessive winding limit switch is stopped, the hoist cables are hoisted to regulate the delivery lengths of the two hoist cables 9A and 9B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jib crane mainly used for loading and unloading a high lift, and can eliminate winding misalignment of a hoisting line for raising and lowering a load through a hook block suspended from the tip of the jib. The present invention relates to a hoisting rope adjusting method and device for a jib crane.

[0002]

2. Description of the Related Art Cranes generally used to carry materials to high places at construction sites of high-rise buildings are
The hoisting rope length is longer than that of normally used cranes. Therefore, in the hoist mounted on the crane, the winding amount of the hoisting rope (wire rope) wound on the drum increases, and not only the diameter of the drum increases but also multi-layer winding. From this situation,
For high-lift hoisting machines, endless hoisting machines are increasingly used as a means for avoiding upsizing.

Further, in a crane used at high lift,
Since the hoisting rope operated by the hoisting machine becomes long, the hook block hung by the hoisting rope at the part suspended from the tip of the boom rotates under the influence of the twisting of the hoisting rope while moving up and down. Occurs. Such a rotation phenomenon of the hoisting rope is dangerous because the transported object suspended by the hook block also rotates. Therefore, in order to prevent the above-mentioned rotation phenomenon of the hoisting rope, the hoisting rope has an opposite S in the twisting direction.
The two twisted ropes and the Z-twisted ropes are operated by independent hoisting machines, and the ends of the two hoisting ropes are connected by hook block support ropes near the hook block to suspend the hook block. It is designed to lower and mutually cancel the rotation phenomenon related to the twisting of both hoisting ropes.

[0004]

However, by using two ropes having different twists as described above and performing winding and unwinding operations by independent winding machines, those winding ropes are connected to the tip portion of the boom. It is possible to prevent the rope from rotating in the part that is hung from the rope, but by separately driving the long rope for several minutes separately with an endless type hoist, it is possible to slightly shift to both ropes during operation. Occurs. If the deviation that occurs in both of the ropes becomes large, the hook block support rope that connects the hoisting ropes will be displaced to an irregular position, and the hook block cannot be properly hung.

Such a deviation of both hoisting ropes does not occur abruptly, but tends to occur as the frequency of lifting and lowering work of materials etc. by the crane increases, and it is not easy to correct the deviation. . In particular, since the installation position of the crane is the top of the structure, etc., it is difficult to restore it once it occurs. In addition to the difference in the elongation of the rope itself, the cause of the deviation of the hoisting rope is due to the difference in the movement amount during the winding and unwinding operations due to the difference in the working diameter of the winding drum in both hoisting machines. It is considered to be due to accumulation.

According to the present invention, hoisting of a jib crane which solves such a problem and can correct the deviation of both hoisting ropes easily in the operation section even if the above-mentioned rope deviation occurs due to the operation of the crane. It is an object of the present invention to provide a rope adjustment method and its device.

[0007]

In order to achieve such an object, a hoisting rope adjusting method of the present invention is a jib crane equipped with an endless hoist, wherein each hoisting rope of S twist and Z twist is independently. By operating the hoisting machine, the drum shafts of the hoisting machines are connected by an electromagnetic clutch to perform synchronous drive, and a weight-type overwinding limit switch provided for each hoisting rope is provided at the tip of the jib. The detector is operated by the switch operation pieces attached to the tip of each hoisting rope, and the operation difference of the overwinding limit switch by the switch operation pieces is stopped. And adjust the feeding length of both hoisting ropes by hoisting the hoisting rope until the other overwinding limit switch is operated. And butterflies.

In the present invention, as an apparatus for carrying out the above method, each of the S-twisted and Z-twisted hoisting ropes is operated by an independent endless hoist to lift the hook block from the tip of the jib. In the jib crane, the drum shafts of those hoisting machines are connected by an electromagnetic clutch so that they can be synchronously driven, and an overwinding limit switch equipped with a weight-type detector is provided at the tip of the jib in association with each hoisting rope. The operation of the electromagnetic clutch is stopped at the same time when the hoisting machine on the hoisting rope side corresponding to the earliest actuation signal of the overwinding limit switch by the switch operation piece attached to both hoisting ropes is stopped. Let me
After that, the other winding machine is connected to an electric control unit capable of adjusting both the winding ropes by stopping driving.

[0009]

According to the present invention having such a structure, the S twist and the Z twist
Each of the twisted hoisting ropes is an independent endless hoisting machine, and usually the electromagnetic clutch connects the drum shafts of both hoisting machines to drive them synchronously, and the hoisting ropes are repeated by repeating both winding and unwinding operations during operation. If a misalignment occurs in the feeding length, the two hoisting machines are operated in the winding direction of the rope, and one of the winding ropes is attached to the end of the jib and the detector of the overwinding limit switch related to the winding rope is attached. When lifted and operates the overwinding limit switch, the operation of the electromagnetic clutch connecting the drum shafts of the both winding machines is stopped, and at the same time, only the winding machine on the overwinding stop side by the overwinding limit switch is stopped, and the other The other hoist will continue to drive until the hoisting rope of the other operator activates the associated overwinding limit switch. As a result, the difference due to the displacement of both hoisting ropes is corrected when the driving of both hoisting machines is stopped. Therefore, for example, at the beginning of work, the hoisting rope is wound by both hoisting machines, and the operation as described above is performed to correct the deviation between the S-twisted rope and the Z-twisted rope to safely carry out the unloading work. You can The device can achieve the object with a simple configuration.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hoisting rope adjusting method for a jib crane according to the present invention will be described below with reference to the drawings of the following concrete example device.

FIG. 1 is a front view of a specific example of a jib crane equipped with a hoisting rope adjusting device of the present invention. FIG. 2 is a view showing roping of the hoisting rope of the jib crane and the undulating rope of the jib shown in FIG. 3A and 3B are views showing an example of an endless hoist, in which FIG. 3A is a plan view and FIG. 3B is a side view.

The jib crane shown in these figures is of the low floor type. In the figure, a swivel board 4 is supported on a base 1 provided with an outrigger 2 via a swivel wheel 3.
A jib 5 is arranged with its base end pivotally attached to a support member 4a provided at the front part of the swivel platen 4. Further, two endless hoisting machines 20 are symmetrically arranged on both sides of the swivel plate 4 with respect to the center of rotation in the longitudinal direction with respect to the center of rotation. The jib 5 has a well-known structure framed to a required length, and has a base end pivotally attached to a supporting member 4a attached to the front part of the swivel 4 as described above, and a gantry frame 6 standing upright on the swivel 4. Is supported by a hoisting winch 10 mounted on the swivel 4 by a hoisting rope 8 laid between the pulley 7 arranged at the top of the car and the tip of the jib 5.

As shown in FIG. 3, the hoisting machine 20 includes two winding drums 23 and 23 'supported by machine frames 22 and 22 with their axes parallel to each other at a required interval and a deceleration drive mechanism (not shown). Power is applied to each winding drum 23, 23 '
Winding drive machine 21 consisting of drive motor 24 for transmission drive to
And a take-up reel 25 for the hoisting rope 9 (9A, 9B) which is arranged at an appropriate distance from the hoisting drive machine 21. As described above, the hoisting drive machine 21 and the take-up reel 25 are arranged symmetrically with respect to the center line of the swivel plate 4, and the take-up drum 23 of each of the hoisting drive machines 21 and 21 is arranged. The shaft 23a is connected so as to be tuned by an electromagnetic clutch 28. The take-up reel 25 is a torque motor.
The reel 25 "is always urged in the winding direction by the 25 'during operation. The reference numeral 25a in the drawing is a rope pressing roller for the reel 25".

The hoisting rope 9 is an S-twisted rope 9A and a Z-twisted rope.
9B and 9B are respectively sent from the take-up reel 25 to the take-up drive machine 21 with a required tension force, and are wound around the take-up drums 23 and 23 'of the respective take-up drive machines 21 a plurality of times and sent out. , Around the pulleys 12 and 12 'provided at the base position of the gantry frame 6 and hang down from the pulley 13 at the tip of the jib 5 through the pulley 13 at the top of the gantry frame 6, and each end is hooked to the hook block support cable 15. Connected to form a series of hoisting lines. The hook block 27 is suspended by the hook block support rope 15. Further, a pulley is provided so that a fleet angle with respect to the take-up reel 25 can be obtained between the take-up reel 25 and the take-up drums 23, 23 'of the take-up drive machine 21.
16 and 17 are arranged, and the hoisting rope 9 can be moved around the pulleys 16 and 17.

At the tip of the jib 5, an overwinding limit switch 18 is provided with an S-twisted rope 9A and a Z-twisted rope 9B of the hoisting rope 9.
It is attached in association with each of. In each of the overwinding limit switches 18, a weight type detector 18a is hung on the operating lever of the switch. And each rope 9A,
In the vicinity of the connection portion with the hook block support cord 15 of 9B, a switch operation piece 19 that raises the weight type detector 18a and operates the overwinding limit switch 18 is provided from the connection portion with the hook block support cord 15. They are installed at positions that are approximately the same size apart. In addition, these overwinding limit switches 18 are usually connected to an operating lever of the switch, and a weight-type detector 18a that is suspended is wound up by the hoisting rope 9 (9
(A, 9B) when the switch operation piece 19 attached to the switch operation piece 19 raises it, the overwinding limit switch 18 operates to stop the excitation of the electromagnetic clutch 28 and the rope (9A or 9B).
It is electrically connected so as to stop the drive of the hoist 20 of B). The control circuit of the electromagnetic clutch 28 is set so that it can be automatically restored at the next start when the driving of the winding machine 20 is stopped. Of course, the overwinding limit switches 18 are automatically returned to the off state when the operating force for lifting the weight type detector 18a is removed.

Next, the operation of the embodiment according to the present invention constructed as above will be described. First, when hoisting work is performed frequently by operating the crane, the hoisting machine 20 causes the hoisting machine 9 (9A, 9A, 9A, 9B)
Since it is a method of driving, the frictional force between the ropes 9A and 9B and the winding drums 23 and 23 'of the hoisting drive machines 21 and 21 is inevitably small in both hoisting machines 20 and 20 during the driving operation. Then, the difference is gradually accumulated and the movement amount of the ropes 9A and 9B is deviated. As a result, the hoisting rope 9 (9A, 9B) is displaced to one side at the hanging portion of the hook block 27 due to long-time operation.

Therefore, in order to correct such a deviation in the hoisting rope 9, for example, both hoisting machines 20 and 20 are operated in the hoisting direction at the start of cargo handling work by a crane.
Then, the hoisting ropes 9A and 9B are hook block supporting ropes.
Since the end portions of the hook block are connected to each other by 15 to form an endless shape, both ends of the hook block supporting rope 15 and the rope 9A,
The switch operation pieces 19, 19 which are attached in the vicinity of the connecting portion with the 9B are lifted in a displaced state. And
When the preceding one of the switch operation pieces 19 and 19 comes into contact with the corresponding weight type detector 18a of the overwinding limit switch 18 arranged in association with the rope (for example, 9A), , The corresponding detector 18a is lifted and the overwinding limit switch 18a
Is activated. Then, the operation control section is operated by the electric signal to stop the operation of the hoisting drive machine 21 that winds the preceding line (for example, 9A) including the switch operation piece 19. At the same time, the excitation of the electromagnetic clutch 28 is stopped, and the synchronous drive of the winding drums 23 and 23 'of both winding drive units 21 and 21 is cut off, and the winding drive unit of the other rope (for example, 9B).
Only 21 will continue to operate.

Eventually, the switch operation piece 19 attached to the side of the subsequent hoisting rope (for example, 9B) comes into contact with the weight-type detector 18a corresponding to the rope and lifts the detector 18a, as described above. The over-winding limit switch 18 corresponding to the signal is sent to the operation control unit to send a signal (for example, 9
The operation of the hoisting drive machine 21 in B) is stopped. as a result,
Similarly, the switch operation pieces 19 and 19 attached to both the ropes 9A and 9B are aligned with the positions where the weight detector 18a of the overwinding limit switch 18 is pushed up and stopped, and in this state the hook block support ropes 15 are After returning to the normal position, the hoisting rope 9 (9
A, 9B) deviation correction is complete. Therefore, when the hoisting machines 20 and 20 are driven thereafter, both hoisting machines 21 and 21 are driven and the electromagnetic clutch 28 is also actuated so that both ropes are unreeled and wound up in a synchronized manner. The cargo handling operation can be performed safely.

It should be noted that even if the hoisting rope 9 is displaced to the left or right depending on the work situation, the above-described correction operation is performed at the start of the cargo handling work for one day, and then the normal work is started. By doing so, since the hook block support cord 15 can be kept in the normal position where there is no deviation at the start of the work, and the cargo handling work can be started, the cargo handling work can be performed safely without causing a shift even if it is dangerous.

[0020]

As described above, according to the present invention, in a high-lift crane of the type in which long hoisting ropes are driven by using two endless hoisting machines, the hoisting machine is inevitably avoided in manufacturing. A shift in the amount of movement caused by the drive of a long hoisting rope, which cannot be done, can be reliably adjusted with a simple configuration, and safe cargo handling work can be performed.

[Brief description of drawings]

FIG. 1 is a front view of a specific example of a jib crane including a hoisting rope adjusting device of the present invention.

FIG. 2 is a diagram showing roping of hoisting ropes of the jib crane shown in FIG. 1 and undulating ropes of the jib.

FIG. 3 is a diagram showing an example of an endless type hoist, in which (a) is a plan view and (b) is a side view.

FIG. 4 is a perspective view showing a mode of correcting the deviation of the rope in the hoisting rope adjustment method of the present invention.

[Explanation of symbols]

5 Jib 9 Hoisting rope 9A One rope 9B The other rope 14 Pulley provided at the tip of the jib 15 Hook block support rope 18 Overwinding limit switch 18a Weight detector of overwinding limit switch 19 Switch operating piece 20 Winding up Machine 21 Winding drive machine 23, 23 'Winding drum 25 Winding reel 27 Hook block 28 Electromagnetic clutch

Claims (2)

[Claims] 1. A jib crane equipped with an endless type hoist, wherein each of the S-twisted and Z-twisted hoisting ropes is operated by the independent hoisting machine, and the drum shafts of the hoisting machines are connected by an electromagnetic clutch. And drive the tuning type weight detector of the overwinding limit switch arranged for each hoisting rope at the tip of the jib with a switch operation piece attached to the tip of each hoisting rope, and switch them. Operational difference of overwinding limit switch by operating piece At the same time as stopping driving of the hoisting machine for the early rope, the connection by the electromagnetic clutch is disconnected, and the hoisting rope is hoisted until the other overwinding limit switch is operated. A hoisting rope adjusting method for a jib crane, which is characterized by adjusting a feeding length of the hoisting rope. 2. A jib crane for hoisting a hook block from the tip of a jib by operating each hoisting rope of S twist and Z twist by an independent endless hoist, and the drum shaft of the hoist is electromagnetically operated. An overwinding limit switch equipped with a weight-type detector is provided at the tip of the jib so as to be driven in synchronization by connecting with a clutch and associated with each of the hoisting ropes. The winding hoist on the side of the hoisting rope corresponding to the earliest actuation signal of either of the overwinding limit switches by the operation piece is stopped and at the same time the operation of the electromagnetic clutch is stopped, and thereafter the other hoisting machine is driven. A hoisting rope adjusting device for a jib crane, wherein the hoisting rope adjusting device is connected to an electric control unit capable of adjusting both the hoisting ropes when stopped.