JPH08259180A - Boom top in telescopic boom - Google Patents

Abstract

PURPOSE: To bend a boom top and to increase a working radius to reduce a distance between a boom and a hook at the time of insertion work by using the telescopic horizontal boom. CONSTITUTION: A rotating bracket 2 capable of overhanging forward around a fulcrum 7 as its center is installed on a head end part of a telescopic boom 1 through a fixing pin 3, a sheave 6 is provided on the rotating bracket 2, a hook is constituted to be hung down by a single suspended wire 5 and a boom top is free to bend.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom top which is effective when carrying out a work (hereinafter referred to as a plugging work) in which a tip end portion of a telescopic boom is projected forward to carry a load from an opening portion of a building or the like, It is particularly suitable for use in the structure of boom tops such as reach tower cranes.

[0002]

2. Description of the Related Art Boom tops usually have the shape shown in FIG. 5 (which will be described later), and as a specific conventional example, a boom top is disclosed in Japanese Utility Model Laid-Open No. 5-54481 and Japanese Patent Laid-Open No. There is one disclosed in Japanese Patent No. 80392. In Japanese Utility Model Laid-Open No. 5-54481, as shown in FIG. 6, a wire locking tool c is arranged at the rear ends of both side plates b of the boom tip a.
A swinging bracket d swingably supported between both side plates b is attached, a pulley e is projected downward from both side plates b, and the pulley e is separated from the wire locking tool c and the pulley e is attached to both side plates. A fixing device f for fixing the swing bracket d is arranged at two positions, that is, a position stored inside b. In addition, JP-A-6-80
Japanese Patent No. 392 has a structure in which a jib including a jib head can be inserted into and removed from the top boom of a telescopic boom to improve operability.

[0003]

However, in the conventional general type as shown in FIG. 5, the space between the boom r and the hook s is increased by the size of the sheave q attached to the boom top p. I could not reduce the distance. Further, the prior art shown in FIG. 6 is intended to prevent the wire rope from being entangled when the boom is raised and to increase the lifting height of the suspended load during the insertion work performed with the boom horizontal. Has a structure in which it can be bent inward and rearward, so there is a problem that the working radius becomes smaller. Further, the one disclosed in Japanese Patent Laid-Open No. 6-80392 aims to shorten the total length of the telescopic boom by allowing the jib to be inserted into and removed from the top boom of the telescopic boom and folding it. With such a configuration, there is a problem that the distance between the boom and the hook does not become short. It is an object of the present invention to solve the above problems.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and a rotary bracket which can be projected forward around a fulcrum is attached to a distal end portion of a telescopic boom via a fixing pin. The sheave is attached to the rotary bracket, the hook is suspended by a single wire, and the tip end of the telescopic boom can be bent.

[0005]

With the above-described structure, the rotary bracket is projected forward, and the sheave provided on the rotary bracket is pulled up to the same height as the lower surface of the telescopic boom, so that it is convenient for loading and unloading the telescopic boom. The distance between the boom and the hook is reduced and the additional working radius provided by the rotating bracket that extends further forward and the structural arrangement using a single wire is added.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side view of the boom top, and FIG. 2 is a front view of FIG.
Is installed. The rotation bracket 2 can be positioned about the fulcrum 7 so as to be positioned in two positions, a state in which it extends to the front of the telescopic boom 1 and a state in which it extends downward,
It is fixed via a fixing pin 3. The hook 4 is suspended by a single wire 5 passing through a sheave 6 provided on the rotating bracket 2.

When the crane is stowed, such as when a crane work vehicle travels, the rotating bracket 2 has a telescopic boom 1.
It is positioned in the lower position of the crane, and in this state, it is exactly the same as the boom top of the conventional crane, and is functionally unchanged.

However, in the case of the insertion work as shown in FIG. 3, the load 9 is suspended by the hook 4 by the telescopic boom 1 in the horizontal state, and the movement of the telescopic boom 1 is used to open it from the opening of a building or the like. It becomes necessary to convey the load 9 to the inner rear side. In this case, if the distance between the telescopic boom 1 and the hook 4 is made as small as possible, the workable range is expanded, the work is facilitated, and the efficiency is improved. Therefore, it is particularly suitable for a reach tower crane or the like.

Referring to FIG. 1, when the rotary bracket 2 is retracted from the retracted state and the fixing pin 3 is replaced so as to project to the front of the telescopic boom 1, the positioning is shortened by the distance H protruding below the telescopic boom 1. The winding allowance of the minute hook 4 is increased.

If the insertion work shown in FIG. 3 is performed in this state, the work of transporting the load 9 to the inner back of a building with a narrow opening becomes easy, so that the crane can be used safely and efficiently. The work done can be performed. Furthermore, by extending the rotating bracket 2 to the front of the telescopic boom 1,
As the sheave 6 attached as shown in the explanatory view of FIG. 4 moves forward with respect to the retracted position, the working radius increases by L, which is advantageous for performing insertion work. come. In this case, it goes without saying that the hook 4 is limited to the one using the single wire 5.

[0011]

The present invention is made as described in detail above, and by providing a boom top, particularly when a reach tower crane is used to perform insertion work using a horizontal boom that expands and contracts, the rotary bracket is moved forward. By overhanging, the distance between the telescopic boom and the hook can be shortened, so that the load can be easily conveyed from the opening having a low height to the inside. Further, according to the present invention, since the sheave moves forward by projecting the structure of the rotary bracket forward, the hook by one hanging wire also moves forward, which has an advantage of increasing the working radius.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of a boom top.

FIG. 2 is a front view of FIG.

FIG. 3 is an explanatory diagram of insertion work.

FIG. 4 is an explanatory diagram of an increase in working radius.

FIG. 5 is an explanatory diagram of a configuration of a conventional boom top.

FIG. 6 is a structural explanatory diagram of Japanese Utility Model Laid-Open No. 5-54481.

[Explanation of symbols]

 1 Telescopic boom 2 Rotating bracket 3 Fixing pin 4 Hook 5 Wire 6 Sheave 7 Support point

Claims (2)

[Claims] 1. A rotating bracket 2 which can be projected forward around a fulcrum 7 at the tip of a telescopic boom 1.
A boom top in a telescopic boom, wherein the telescopic boom 1 is attached via a fixing pin 3, a hook 4 is suspended from the rotary bracket 2, and the tip of the telescopic boom 1 can be bent. 2. The boom top for a telescopic boom according to claim 1, wherein the rotary bracket 2 is provided with a sheave 6 so that the hook 4 can be suspended by a single wire 5.