JP3160253B2 - Crane load cell removal mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load cell removing mechanism for measuring a tension applied to a jib hoisting rope of a crane.

[0002]

2. Description of the Related Art FIG. 4 is a side view of a general crawler crane.
Is mounted to be able to turn freely. A lattice jib 3 is attached to the front part of the upper swing body 2 so as to be able to undulate, and an upper strut 4 and a back stay 5 are provided at the rear part.
Is provided. This A frame is also called a mast. A bail frame 6 is rotatably attached to the top of the A frame, and an equalizer sheave 7 is attached to the bail frame 6 via a load cell (not shown).

[0003] A jib hoisting rope 9 is provided between the bail frame 6, the equalizer sheave 7, and the bridle 8.
Is wound, and a jib support rope 10 is stretched between the bridle 8 and the tip of the lattice jib 3. The bail frame 6 and the bridle 8 are wound when the jib hoisting rope 9 is wound on an auxiliary winding drum provided on the upper swing body 2 or is unwound from the auxiliary winding drum.
The distance between them is adjusted so that the lattice jib 3 undulates.

[0004] At this time, the tension applied to the jib hoisting rope 9 is detected by a load cell attached between the bail frame 6 and the equalizer sheave 7. When the load cell detects that a tension equal to or more than a predetermined load is applied to the jib hoisting rope 9, the safety device operates to prevent the jib hoisting rope 9 from being damaged.

[0005] A hoisting rope 11 is hung on the tip of the lattice jib 3, and a hook 12 is suspended from the hoisting rope 11. When the hoisting rope 11 is wound on or pulled out from the main winding drum provided on the upper revolving unit 2, the hook 12 is moved up and down, and the load is lifted and lowered.

[0006]

However, in such a crane, adjustment and replacement of the load cell attached to the equalizer sheave 7 required labor and time. That is, it is necessary to remove the load cell in order to adjust or replace the load cell, and for that purpose, it is necessary to remove the equalizer sheave 7. In order to remove the equalizer sheave 7, it is necessary to remove the jib hoisting rope 9 from the bail frame 6, the equalizer sheave 7 and the bridle 8, which requires labor and time.

Further, another crane is required as a companion machine for holding the removed equalizer sheave 7, and adjustment and replacement of the load cell cannot be performed easily. In addition, since these operations are performed for a long time at a high place, there is a great danger that the worker will fall.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a bail frame rotatably mounted on the top of an A-frame and a bail frame mounted on the bail frame via a load cell. A coupling mechanism that couples between the equalized sheaves, a telescopic mechanism that expands and contracts the distance between the bail frame and the equalizer sheave coupled by the coupling mechanism, and a loosening rope that is wound between the bail frame and the equalizer sheave. A holding mechanism for holding the hanging equalizer sheave, and a guide mechanism for guiding the movement of the equalizer sheave held by the holding mechanism when the distance between the bail frame and the equalizer sheave is expanded and contracted by the expansion and contraction mechanism. The load cell removal mechanism was configured.

In the removal of the load cell in this configuration, first, the jib hoisting rope is loosened, and the hanging equalizer sheave is held by the holding mechanism. Next, in this state, the bail frame and the equalizer sheave are connected by the connection mechanism, and then the connection distance between the bail frame and the equalizer sheave is reduced by the extension mechanism against the bending force of the jib hoisting rope. At this time, the movement of the equalizer sheave is guided by the guide mechanism. The load cell provided between the bail frame and the equalizer sheave can be easily removed because the pin for fixing the load cell is easily pulled out by reducing the distance therebetween.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment in which a load cell removing mechanism for a crane according to the present invention is applied to the aforementioned crawler crane will be described.

FIG. 1B is a partially enlarged side view showing the vicinity of the top of the A-frame of the crane provided with the load cell removing mechanism according to the present embodiment, and FIG. 1A is the same as FIG.
FIG. 4 is a plan view as viewed from a direction indicated by an arrow A. In this figure, the same or corresponding parts as those in FIG. 4 are denoted by the same reference numerals.

A bail frame 6 is rotatably mounted on the top of the A frame including the upper strut 4 and the back stay 5, and a load cell 13 is mounted between the bail frame 6 and the equalizer sheave 7. I have. The load cell 13 and the equalizer sheave 7 are fixed by vertical pins 14, and the load cell 13 and the bail frame 6 are fixed by horizontal pins 15. The equalizer sheave 7 is a sheave with a swing mechanism used to evenly support the pulling force of a jib hoisting rope spanned over a plurality of sheaves.

Further, the upper strut 4 is provided with a pair of brackets 16 which oppose both sides of the equalizer sheave 7 and support the both sides. The bracket 16 constitutes a holding mechanism for holding the hanging equalizer sheave 7 by loosening the jib hoisting rope wound between the bail frame 6 and the equalizer sheave 7, and the bail frame 6 and the equalizer sheave 7 by a telescopic mechanism described later. A guide mechanism that guides the movement of the equalizer sheave 7 when the distance between them is expanded or contracted.

FIG. 2 is a partially enlarged plan view showing a part of the plan view shown in FIG. 1A in a further enlarged manner. In FIG. 2, the same parts as those in FIG. The description is omitted. As shown in the figure, a pair of lugs 7a, 7a are welded to both ends of the equalizer sheave 7, and
A pair of lugs 6a, 6a are also welded to both ends of the bail frame 6. A rod shown in FIG. 3 is connected between the lugs 6a and 7a.

The rod includes a first rod 21 having a right or left thread, a second rod 22 having a left or right thread, and first and second rods 21, 21.
And a turnbuckle 23 screwed into the turnpiece 22. The turnbuckle 23 is a nut having a right-hand thread on one end and a left-hand thread on the other end.

The first and second rods 21 and 22 have pin holes 21a and 22a, respectively. The first rod 21 has a pin hole 21a and a pin hole (not shown) opened in the lug 6a. One end is fixed to the bail frame 6 by inserting the pin. Also, the second rod 2
2 has one end fixed to the equalizer sheave 7 by inserting a pin into the pin hole 22a and a pin hole (not shown) opened in the lug 7a.

The rod shown in FIG. 3 constitutes a coupling mechanism for coupling between the bail frame 6 and the equalizer sheave 7, and extends and reduces the coupling distance between the bail frame 6 and the equalizer sheave 7 coupled by this coupling mechanism. It constitutes a telescopic mechanism.

The removal of the load cell 13 by the load cell removing mechanism according to the embodiment is performed as follows.

Normally, when the crawler crane is operating, the bail frame 6 is in a state of standing up and facing upward as shown in FIG. To remove the load cell 13 for adjustment or replacement of the load cell 13, first, the tension of the jib hoisting rope is relaxed. When the jib hoisting rope is loosened, the bail frame 6 hangs down in the direction of arrow B, and both sides of the equalizer sheave 7 are held on the bracket 16. Next, in this state, the rod shown in FIG. 3 is connected and coupled between the bail frame 6 and the equalizer sheave 7.

Subsequently, the turnbuckle 23 is turned in the direction indicated by the arrow C (see FIG. 3), and the distance between the lugs 6a, 7a, that is, the coupling distance between the bail frame 6 and the equalizer sheave 7, changes the deflection of the jib hoisting rope. Shrunk against power. At this time, the movement of the equalizer sheave 7 is guided by the bracket 16 having a support surface formed along the moving direction of the equalizer sheave 7.

The load cell 13 provided between the bail frame 6 and the equalizer sheave 7 has a pin 1 for fixing the load cell 13 by reducing the distance therebetween.
Since 4 and 15 come off easily, they can be easily removed.

After the adjustment and replacement work of the load cell 13 is completed, the turnbuckle 23 is moved in the direction of arrow D (see FIG. 3).
And the rod is extended, the work proceeds in the reverse procedure to the above, the rod is removed, and the working state is restored.

According to the load cell removing mechanism according to the present embodiment, the adjustment and replacement of the load cell 13 can be performed reliably, easily and safely by simply fixing the equalizer sheave 7 with a rod. Can be done.

In the above embodiment, the case where the coupling mechanism and the extension mechanism are constituted by the first and second rods 21 and 22 and the rod composed of the turnbuckle 23 has been described. is not. For example, a structure in which the coupling mechanism and the extension mechanism are configured from a chain block in which the hook at one end of the load chain is hooked on the bail frame 6 and the hook at the other end of the load chain is hooked on the equalizer sheave 7.

In the above embodiment, the case where the holding mechanism and the guide mechanism are constituted by the bracket 16 has been described, but the invention is not limited to this.
For example, the upper strut 4 itself may have a holding mechanism and a guide mechanism. That is, both sides of the equalizer sheave 7 are extended to face the respective back surfaces of the pair of upper struts 4, and both sides of the equalizer sheave 7 are held on the respective back surfaces of the upper struts 4,
The movement of the equalizer sheave 7 may be guided along each of the back surfaces.

The same effects as those of the above-described embodiment can be obtained by each of the above configurations.

[0027]

As described above, according to the present invention, when the load cell is removed, the jib hoisting rope is loosened, the equalizer sheave is held by the holding mechanism, and the bail frame and the equalizer sheave are connected by the connecting mechanism. This is performed by shortening the coupling distance between the bail frame and the equalizer sheave by the telescopic mechanism.

Therefore, according to the load cell removing mechanism of the present invention, the adjustment and replacement of the load cell can be performed in a short time without requiring any labor, and further, no competing machine is required. Therefore, dangerous high-altitude work is completed in a short time, and work safety is improved.

[Brief description of the drawings]

FIG. 1A is a partially enlarged plan view of a crane provided with a load cell removing mechanism according to an embodiment of the present invention, and FIG. 1B is a partially enlarged side view of an A-frame top of the crane.

FIG. 2 is a partially enlarged plan view showing a part of FIG.

FIG. 3 is a view showing a rod constituting the load cell removing mechanism according to the embodiment.

FIG. 4 is a side view of a general crawler crane.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 4 ... Upper strut 5 ... Back stay 6 ... Bail frame 6a, 7a ... Lug 7 ... Equalizer sieve 13 ... Load cell 14, 15 ... Pin 16 ... Bracket 21, 22 ... First and second rod 23 ... Turnbuckle

Claims (4)

(57) [Claims] 1. A bail frame rotatably attached to the top of an A frame, a coupling mechanism for coupling between equalizer sheaves attached to the bail frame via a load cell, and the bail coupled by the coupling mechanism A telescopic mechanism that expands and contracts the distance between a frame and the equalizer sheave, a holding mechanism that holds the equalizer sheave that hangs down by loosening the undulating rope wound between the bail frame and the equalizer sheave, and the bail that is formed by the telescopic mechanism. A load cell removing mechanism for a crane, comprising: a guide mechanism for guiding the movement of the equalizer sheave held by the holding mechanism when the distance between the frame and the equalizer sheave is expanded or contracted. 2. The coupling mechanism and the telescopic mechanism include a first rod having one end fixed to the bail frame and having a right or left thread, and a left or right screw having one end fixed to the equalizer sheave. The load cell removing mechanism for a crane according to claim 1, further comprising a second rod cut off, and a turnbuckle screwed to each of the first and second rods. 3. The coupling mechanism and the extension mechanism include a chain block in which a hook at one end of a load chain is hooked on the bail frame, and a hook on the other end of the load chain is hooked on the equalizer sheave. The load cell removing mechanism for a crane according to claim 1, wherein: 4. The apparatus according to claim 1, wherein the holding mechanism and the guide mechanism include a bracket provided on an upper strut of the A frame, the support surface having a support surface formed along a moving direction of the equalizer sheave. The load cell removing mechanism for a crane according to claim 2 or 3, wherein