JPS5810356B2 - How to remove the counterweight of a mobile crane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for attaching and detaching a counterweight to a mobile crane, and more specifically, the present invention relates to a method for attaching and detaching a counterweight to a mobile crane. This article relates to a method for removing a crane counterweight.

BACKGROUND ART Among mobile cranes such as crawler cranes, truck cranes, etc., there is one type in which a counterweight mounting table is provided extending from the rear of the frame of the revolving body, and the counterweight is mounted on the mounting table.

Generally, in mobile cranes, all counterweights are removed before transportation.

In the above-mentioned mobile crane, the counterweight is generally attached and detached using a separate crane.

However, using a separate crane not only makes it troublesome to attach and detach the counterweight, but also causes the inconvenience that the counterweight cannot be attached and detached if the crane is not available at hand.

In order to improve these points, in the field of mobile cranes equipped with counterweights, various attachment/detachment devices that can attach and detach the counterweight without using a separate crane have been proposed and put into practical use.

An example thereof is shown in FIGS. 1 to 5.

As shown in FIGS. 1 to 3, this counterweight attachment/detachment device connects a counterweight suspension rope 4 to a top shaft 3 of an A-shaped frame 2 attached to the upper part of a crane body 1, and 1, guide the rope 4 and move the counterweight 5 to its set position (crane body 1
A guide sheave 6 that can be vertically moved up and down from the rear lower surface) is provided, and a vertical cylinder 7 for raising and lowering the top shaft is installed between the lower part of the crane body 1 and the top shaft 3 of the A-shaped frame 2. It becomes.

To remove the counterweight 5 using this device, first, as shown in FIG. Hang it at.

Next, as shown in FIG. 5, the vertical cylinder 7 is reduced to form A.
By lowering the top shaft 3 of the shaped frame 20, the counterweight 5 is lowered to the ground.

Moreover, when attaching the counterweight 5, the operation described above is reversed.

. However, the above-mentioned counterweight attachment/detachment device was proposed only for the case where the counterweight was attached to the rear lower surface of the crane main body 1, and the counterweight attachment/detachment device was proposed only for the case where the counterweight was attached to the rear lower surface of the crane main body 1, and the counterweight attachment/detachment device was proposed only for the case where the counterweight was attached to the rear lower surface of the crane body 1. It is impossible to do this.

That is, in order to remove the counterweight on the counterweight mounting table, it is necessary to move the counterweight in a direction away from the mounting table. 4 is guided vertically by the Guyton-Pro into the counterweight set position, so that it is impossible to move it from the suspended counterweight mounting platform.

As mentioned above, in a mobile crane of the type in which a counterweight is attached to the rear lower surface of the crane body, when installing the counterweight 5, the counterweight 5 must be installed in a state in which the counterweight 5 is suspended by the rope 4. Therefore, there is a drawback that the installation work is dangerous.

On the other hand, it is not necessary to use a separate crane for a mobile crane that mounts a counterweight on a counterweight mounting table. Something has been disclosed.

. This attachment/detachment device arranges a strut and a stay on a rotating frame between a counterweight and a boom, the free ends of both of which are pivoted, and the base of the stay is connected to the rotating frame, and the base of the strut is connected to the rotating frame. It is configured such that it is replaceably attached to the base end of the boom, a sheave is provided at the attachment point between the strut and the stay, and a counterweight lifting rope is wound around the sheave and connected to the winch drum.

This device consists of a stay and a strut.

The counterweight is attached and detached by one operation in which the swinging frame is raised and lowered by a boom cylinder, and in cooperation with the operation of a hoisting device including a winch drum and a rope for lifting the counterweight 1.

However, with this counterweight attachment/detachment device, the base of the strut is changed from the swing frame to the base end of the boom.
Since the swing frame is only able to swing when the boom is raised and lowered, not only does it require replacement work to attach the strut base, but it also requires the lifting and lowering of the counterweight, as well as the lifting and lowering of the counterweight. There is a drawback that power is required for any movement.

Furthermore, since the winch drum of the hoisting device is provided within the revolving frame, space must be secured within the revolving frame.

As a result, it becomes necessary to change the arrangement of the mechanical parts of the pond or to increase the size of the swing frame itself.

In other words, it is necessary to change the configuration of the rotating frame.

The purpose of the present invention is to solve the problems of the prior art described above,
The counterweight on the counterweight mounting table can be easily and safely attached and detached without using a separate crane, and there is no need to change the attachment of the A-frame base or raise or lower the boom. To provide a method for removing a counterweight of a mobile crane that uses power only when lifting and does not require power when lowering.

In order to achieve this object, the present invention includes a counterweight mounting table provided at the rear of the crane main body, a counterweight mounted on the mounting table, and a poom lifting doll mounted on the upper part of the crane main body. 1. A hydraulic cylinder for raising and lowering the A-frame is interposed between the top shaft of the A-frame and the crane body, and the hydraulic cylinder is operated to move the A-frame backward. The A-shaped frame is laid down, a chain block is passed between the top shaft of the A-shaped frame and the counterweight at this position to create tension, and the A-shaped frame is raised by operating the hydraulic cylinder to place the counterweight on a counterweight mounting table. At the same time as sliding the top and moving the way of thinking,
The counterweight is suspended at a position separated from the counterweight mounting table, and then the chain block is operated to suspend the counterweight.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 6 is an overall side view of a crawler crane equipped with a device for implementing the counterweight attachment/detachment method according to the present invention;
The figure shows a rear view of the counterweight mounting part in FIG. 6 in which a chain block is housed, and FIG. 8 shows a cross-sectional side view of FIG. 7.

In the figure, an upper rotating body 12 is mounted on a lower traveling body 11, and a crane boom 13 is attached to the front part of the rotating body 12.

Further, a foldable boom raising doll frame 14 is attached to the upper part of the revolving body 12.

The A-shaped frame 14 has a front leg 14A whose base part is pivotally connected to the backstay mounting frame 15 on the revolving body 12, and one end which is attached to the front leg 14A.
The rear legs 14E are extendable and retractable, and the other end is pivotally connected to the top of the revolving body 12.

Further, an extending counterweight mounting table 16 is provided at the rear part of the frame of the revolving body 12, and two counterweights 17 stacked one on top of the other in the front and back are mounted on the mounting table 16.
A and 17B are placed.

The inner counterweight 17B is directly fixed to the rear part of the frame of the rotating body 12 via bolts 18, and the outer counterweight 17A is fixed to the counterweight 11B via bolts 19.

In the apparatus for implementing the counterweight attachment/detachment method according to the present invention, the top of the A-shaped frame 14 and the rotating body 12 are
An A-shaped frame hoisting hydraulic cylinder 20 is interposed between the lower part of the A-shaped frame and each of the counterweights 17A, 18B.
A chain block locking bracket 21 is attached to the upper part of the A-shaped frame 14 folded with the bracket.
A chain block 22 for suspending a counterweight is connected to the top shaft of the shaft.

More specifically, in the hydraulic cylinder 20, the base end of the cylinder 20A is pivotally attached to the lower part of the frame of the rotating body 12, and the tip of the piston rond 20B is pivotally attached to the front leg 14A and the rear leg 14B of the A-shaped frame 14. top shaft 1
Connected to 4C.

Then, by expanding and contracting the piston rond 20B of the hydraulic cylinder 20, the A-shaped frame 14 is moved to its front leg 14.
It can be undulated using the proximal pivot point of A as a fulcrum.

That is, the top shaft 140 is configured to perform an arcuate motion, and the range of movement of this arcuate motion is set to a range in which the counterweight separates from the counterweight mounting table.

Further, the chain block 22 has a hydraulic cylinder 20
The chain 22A is arranged on both sides of the counterweight, and one end of the chain 22A can be hooked to a bracket 14D provided on the top shaft 140 via a hook 22B, and the other end of the chain 22A is hooked to a bracket 21 of each counterweight. 220
It is designed so that it can be locked through 5.

□Next, the process of attaching and detaching the counterweight according to the present invention will be explained.

(1) Removal of counterweight.

First, as shown in FIG. 9, the piston rod 20B of the hydraulic cylinder 20 is reduced and
A-shaped frame 14 until 0 reaches the folding position of position a.
Defeat.

Next, the chain blocks 22 are respectively locked to the top shaft 140 and the outer counterweight 17A, and the chain blocks 22 are tensioned, and the bolts 19 attaching the counterweight 17A are removed.

After that, the top shaft 1 is opened by extending the hydraulic cylinder 20.
Raise the A-shaped frame 14 so that 4c is at position b.

As a result, the male counterweight 17A, suspended by the chain block 22, moves while sliding on the counterweight mounting base 16 to the position I on the imaginary line, and is removed from the counterweight mounting base 16.

Next, when the top shaft 140 of the A-shaped frame 14 is lowered again to position a by the contraction operation of the hydraulic cylinder 20, the counterweight 17A moves to the position indicated by the imaginary line ■.

Then, the chain block 22 is operated to extend the chain 22A, and the counterweight 17A is landed on the ground as shown by the imaginary line (2), and the chain block 22 and the counterweight 17A are disengaged.

Next, carry the counterweight 17A, or place the next counterweight next to the counterweight 17A)
Move the crane forward enough to secure a space for 17B to land.

After that, as shown in FIG.
The top shaft 140 at the a position and the counterweight 17B
At the same time as tightening it, remove the mounting bolt 18 of the counterway) 17B.

After that, the top shaft 14 is opened by extending the hydraulic cylinder 20.
0 to C position and d position.

As a result, the counterweight 17B is suspended by the chain block 22 and is moved along the virtual lines (2) and (V) while sliding on the counterweight mounting table.

Next, the top shaft 14 is compressed by a contraction operation of the hydraulic cylinder 20.
By lowering the counterweight 17B to the position a, the counterweight 17B moves to a position away from the counterweight mounting table 16 as shown by the imaginary line (3) and is suspended.

Thereafter, the chain block 22 is operated in the same manner as the counterweight 17A described above to land the counterweight 17B and release the lock between the chain block 22 and the counterweight 17B.

With the above steps, the counterweight removal work is completed.

(2) Installing the counterweight.

First, as shown in FIG. 11, the A-shaped frame 14 is collapsed by contracting the hydraulic cylinder 20.

Then, the chain block 22 is connected to the top shaft 140 and the counterweight 17B placed on the ground, and the chain block 22 is tensioned.

Next, the top shaft 140 is raised to the e position and the f position by extending the hydraulic cylinder.

As a result, the counterweight 11B is lifted up via the chain block 22 along the imaginary lines (2) and (3).

Then, the top shaft 140 is further raised to the g position.

That is, the counterweight 17B is positioned directly above the set position as shown by the imaginary line (3).

Thereafter, by operating the chain block 22, the chain is extended and the counterweight 17B is placed on the mounting table 16, and the counterweight 17B is fixed to the rear part of the frame of the revolving structure 12 via bolts, and the chain is extended. Unlock block 22.

Further, the counterweight 17A is placed on the set position of the counterweight mounting table 16 by the same operation as described above, and is fixed to the previously attached counterweight 17B via bolts.

This completes the installation of the counterweight.

Therefore, according to the present invention, the counterweight mounted on the counterweight mounting table can be attached and detached without using a separate crane.

Furthermore, when attaching and detaching the counterweight, the counterweight is suspended by a hydraulic cylinder and is carried out by a suspended chain block, so power can be saved accordingly. Since it is only performed when the machine is in use, the operating force required for the operation is small.

Further, when attaching and detaching the counterweight, there is no need to change the attachment of the base of the A-frame and to raise and lower the pool 14.

Further, since there is no need to provide a winch drum for suspending a counterweight in the revolving upper body 1.2 as in the prior art, there is no need to change the configuration of the revolving upper body 12.

Next, a description will be given of how to remove the counterweight when three counterweights are provided.

FIG. 12 shows the state in which the third counterweight, that is, the innermost counterweight 170, is removed.

In this figure, it is assumed that the outermost and central counterweights have already been removed by the operations shown in FIGS. 9 and 10.

However, if the innermost counterweight 170 is removed by the same operation as shown in FIG. 10, the following problem will occur.

That is, since the locking point of the chain block 22 on the counterweight 170 is located considerably inside the top shaft 140 of the A-shaped frame 14, the top shaft 14
0 from position a to position h to position j to move counterway) 170 to the position of virtual line M, the frictional force between said counterway) 170 and its mounting table 16, and the chain Due to the relationship between the position of the center of gravity of the counterweight and the locking point of the block 22, the counterweight 170 is tilted as shown by the virtual line ■.

In particular, if the frictional force becomes large, there is a risk that the counterweight 170 will fall over.

However, in the counterweight removal method according to the present invention, since the counterweight is moved while sliding on the counterweight mounting table, the counterweight mounting table 16 is placed on the underside of the counterweight 170 as shown in FIG.
By providing the rollers 23 that move over the counterweight 17C, the frictional force between the counterweight 17C and the mounting table 16 can be reduced and the counterweight 17C can be moved smoothly.

Then, the counterweight 17C is removed by the following operation.

That is, after connecting the chain block 22 to the top shaft 14C and counterweight 17C of the A-shaped frame 14 at position a, the top shaft 140 is raised to position a.

At this time, since the frictional force between the counterweight 170 and its mounting table 16 is reduced by the rollers 23, the counterweight 170 moves to the X2 position without falling over.

Next, the top shaft 140 is lowered once to position a to shorten the length of the chain block 22.

Then, the top shaft 140 is raised again to the e position and the counterweight 17C is moved to the XIV position.

That is, the counterweight 17C is moved to a position away from the mounting table 16 and is landed on the ground by operating the chain block 22.

In addition, in the above embodiment, the case where a plurality of counterweights are attached and detached has been described, but the present invention is not limited to such an embodiment, and the counterweight can be attached to a counterweight mounting table. If so, it can be applied to one location.

As explained above, according to the present invention, the counterweight mounted on the counterweight mounting table can be attached and removed without using a separate crane, and the counterweight can be removed while sliding on the counterweight mounting table. This has the advantage of not causing unstable operation.

Furthermore, in the operation of attaching and detaching the counterweight, the counterweight is suspended by a hydraulic cylinder and suspended by a chain block, so that the operating force of the chain block can be reduced.

Furthermore, there is no need to replace the A-frame base or to raise and lower the boom, and there is no need to change the structure of the crane body.

[Brief explanation of drawings]

Figure 1 is a side view of a mobile crane equipped with a conventional counterweight attachment/detaching device, Figures 2 and 3 are side and rear views showing the main parts of the counterweight attachment/detaching device, and Figures 4 and 5. is a diagram illustrating the situation when the counterweight is removed. Figure 6 is an overall side view of a crawler crane equipped with a device used in the counterweight attachment/detaching method of the present invention, 1. Figure 7 is a rear view of the counterweight attachment/detachment device shown in Figure 6 with a chain block stored therein, and Figure 8 is a sectional side view of Fig. 1, Figs. 9 and 10 are explanatory diagrams of the situation when the counterweight is removed, Fig. 11 is an explanatory diagram of the situation when the counterweight is installed, and Fig. 12 is an explanatory diagram of the situation when the counterweight is removed. FIG. 13 is an explanatory diagram of the situation in which the third counterweight is being removed by the counterweight attachment/detaching device shown in the figure, and FIG. 13 is an explanatory diagram of the situation when the third counterweight is being removed according to the present invention. 12... Upper revolving body, 14... A-type frame, 14
A... Front leg of A-type frame for boom extension, 14B...
- Rear leg of A-type frame, 140...Top shaft of A-type frame, 16...Counterweight mounting table, 17A, 1
7B, 17C... Counterweight, 20... Hydraulic cylinder for raising and lowering the A-type frame, 21... Bracket for locking chain block, 22... Chain block for suspending counterweight, 23... Roller.

Claims (1)

[Claims] 1. In a mobile crane equipped with a counterweight mounting platform provided at the rear of the crane body, a counterweight mounted on the mounting platform, and an A-type frame for boom extension mounted on the upper part of the crane body, A hydraulic cylinder for raising and lowering the A-frame is interposed between the top shaft of the A-frame and the crane body, the hydraulic cylinder is operated to lower the A-frame backwards, and the top of the A-frame is lowered at this position. A chain block is placed between the shaft and the counterweight to create tension, and then the hydraulic cylinder is operated to raise the A-shaped frame to move the counterweight backward while sliding it on the counterweight mounting table. A method for removing a counterweight from a mobile crane, comprising suspending the counterweight at a position removed from a counterweight mounting base, and then operating the chain block to lower the counterweight.