JPS595039Y2 - Mobile crane boom back stop - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a boom backstop that prevents the boom from being raised too much in a mobile crane.

As shown in FIG. 1, in a normal mobile crane 1, a boom backstop 3 is interposed between the boom 2 and the A-frame 4 to prevent the boom 2 from exceeding a limited elevation angle.

A conventional boom backstop of this type has a structure shown in FIG.

In other words, to prevent the boom from lifting too high, there is a first support) 3A whose base end is pivotally attached to the boom 2 side, and a first support) 3A.
A second support) 3B which is slidably fitted into the A-frame 4 side and whose base end is pivoted to the A frame 4 side, a flange F1 attached to the base end of the first support) 3A, and the tip of the second support 3B. The spring 3C is interposed between the flange F2 and the flange F2 attached to the flange F2.

The spring 3C has one end held down by the distal end flange F2 of the second support 3B via a spring suppressor 3D, and the other end is a free end.

The spring retainer 3D is fixed to the flange F2 by welding.

In the boom backstop, when the boom 2 extends to the maximum allowable elevation angle, the free end of the spring 3C comes into contact with the proximal flange F1 of the first support 3A to suppress the extension movement of the boom 2, Further, by absorbing the shock at the time of contact with the spring 3C, the boom is prevented from rising too high.

Therefore, the operator can safely perform work near the maximum allowable elevation angle of the boom 2 by visually observing the gap between the free end of the spring 3C and the proximal flange F2 of the first support 3A.

However, in the above-described boom backstop, the spring 3C is placed close to the boom 2, so when the boom 2 vibrates violently during vibratory work, the vibrations of the boom 2 are transmitted to the spring 3C. There is a problem in that the spring 3C vibrates violently and generates large noise.

In order to prevent this, as shown in Figure 3, the entire boom backstop 3 is inverted and installed (i.e. the first support).
It is conceivable to pivot the spring 3A to the A-frame 4 and the second support 3B to the boom 2 to move the spring 3C, which is a source of noise, away from the boom 2.

However, even if the spring 3C is located away from the boom 2, since the second support (3B) that suppresses the spring 3C is pivotally attached to the boom 2, the vibrations from the boom 2 will cause the spring to spring in the same way as described above. This will propagate to 3C and generate large noise.

The purpose of this invention is to solve the problems of the prior art mentioned above,
To provide a boom backstop for a mobile crane that does not generate large noise from a spring even when performing work in which the boom vibrates violently, such as vibro work.

In order to achieve this purpose, the present invention includes a first support whose base end is pivotally connected to the boom side, and a base end which is slidably inserted into the first support to prevent the boom from lifting too high. a second support pivotally attached to the A-frame side, and a shock absorbing spring interposed between a flange attached to the base end side of the first support and a flange attached to the distal end side of the second support. , in a boom backstop for a mobile crane in which one end of the spring is held down by a front end flange of a second support via a spring stopper, the first and second supports are configured to be installed with the first and second supports reversed. The spring retainer is also removably attached to the distal end flange of the second support via bolts, and the proximal flange of the first support is provided with bolt holes for attaching the spring retainer. be.

The details of the present invention will be explained below with reference to the drawings.

FIG. 4 shows the structure of the boom backstop according to the present invention.

This boom backstop 13 is slidably inserted into a first support 13A whose base end is pivoted to the boom 2 side to prevent the boom from lifting too high as shown in FIG. , and a second support) 13B whose base end is pivotally attached to the A frame 4 side, a flange F3 attached to the base end of the first support) 13A, and a flange F4 attached to the tip of the second support) 13B. A shock absorbing spring 13C is provided between the shock absorbing springs 13C and 13C.

The spring 3C has one end attached to the tip side flange F4 of the second support 13B in the spring retainer 13D.
The other end is a free end.

Thus, in the boom backstop according to the present invention, the spring restrainer 13D is detachably attached to the tip flange F4 of the second support 13B via the bolt 13E.

In addition, the proximal flange F3 of the first support 13A includes
A bolt hole 14 for attaching a spring retainer is drilled.

The entire boom backstop can then be flipped over and installed.

Therefore, in the boom backstop according to the present invention,
When performing general crane work, the spring 13C is mounted on the boom 2 side as shown.

That is, the base end of the first support 13A is pivoted to the boom 2 side, and the base end of the second support 13B is pivoted to the A frame 4 side.

As a result, the operator can safely perform work near the maximum allowable elevation angle of the boom 2 by visually observing the gap between the free end of the spring 13C and the proximal flange F3 of the first support 13A.

On the other hand, when performing work in which the boom 2 vibrates violently, such as vibro work, the boom backstop 13 itself is attached as shown in FIG.

That is, the base end of the second support 13B is pivotally attached to the boom 2 side, and the base end of the first support 1-13A is pivotally attached to the A frame 4 side, and the spring retainer 13D is removed from the spring retainer 13E. 13D second support 13B
Remove it from the tip side flange F4.

Then, the spring 13C is moved to the proximal flange F3 of the first support 13A, and the spring retainer 13D is attached to the proximal flange F3 via its bolt hole 14 and the support 13E.

As a result, the spring 13C is suppressed at the base end of the first support 13A to which vibrations of the boom 2 are difficult to propagate, thereby preventing noise caused by the vibrations of the spring 13C.

As explained above, according to the present invention, it is possible to perform the original function as a boom backstop during general crane work, and also to reduce the noise caused by spring vibration during work where the boom vibrates violently such as vibro work. Occurrence can be prevented.

[Brief explanation of drawings]

Figure 1 is a side view of a mobile crane equipped with a boom backstop, Figure 2 is a side view showing a conventional boom backstop, and Figure 3 is a mobile crane with a conventional boom backstop installed in reverse. 4 is a side view showing the boom backstop according to the present invention, and FIG. 5 is a side view showing the boom backstop according to the present invention installed inverted. 2...Boom, 4...A frame, 13...Boom backstop, 13A...1st support, 13B
...Second support, 13C...Shock absorption spring, 13D...Spring suppressor, 13E...Spring suppressor mounting bolt, F3...Proximal side flange of first support, F4...No. 2 Support tip side 7 lange, 14... Bolt hole for spring restraint installation.

Claims (1)

[Scope of utility model registration request] A first support whose base end is pivotally attached to the boom side, a second support which is slidably inserted into the first support and whose base end is pivotally attached to the A frame side, and a base of the first support. A spring for preventing the boom from rising too high is interposed between a flange attached to the end side and a flange attached to the tip side of the second support, and one end of the spring applies a spring restraint to the tip side flange of the second support. A boom backstop for a mobile crane is configured such that the first and second supports can be installed inverted, and the spring retainer is attached to the tip side flange of the second support via bolts. Detachably installed, the first
A boom backstop for mobile cranes that features bolt holes for mounting spring restraints on the base end flange of the support.