JPH082892A - Sheave fitting structure of multistage telescopic boom - Google Patents

Abstract

PURPOSE:To enable a sheave to be assembled into a multistage telescopic boom even if a clearance between the tip boom and the intermediate boom is narrow. CONSTITUTION:An elongation sheave 7 where a whirl-stop pin 20 having a bolt hole 21 at the outer end and a flange 22 at the inner end is previously assembled into a shaft hole 23 is inserted in a clearance between the tip boom 3 and the intermediate boom 2, a sheave shaft 26 having a pin hole 24 where the whirl stop pin 20 is fitted and a bolt insert hole 25 is fitted in the shaft hole 23 of the elongation sheave 7 from the outside of the intermediate boom 2, a connecting bolt 27 is screw-fitted to the bolt hole 21 of the whirl-stop pin 20 from the outside of the sheave shaft 26, and the sheave shaft 26 is fixed to the intermediate boom by a fixing bolt 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheave mounting structure for a multi-stage telescopic boom, in which a sheave is attached to an intermediate boom of a multi-stage telescopic boom such as an aerial work vehicle or a specially equipped vehicle with a boom.

[0002]

2. Description of the Related Art A base boom, an intermediate boom and a tip boom are provided, and a hydraulic cylinder for expansion and contraction is provided between the base boom and the intermediate boom, and the expansion and contraction operation of this hydraulic cylinder is provided at an appropriate position of the intermediate boom. In a multi-stage telescopic boom configured to extend and retract the intermediate boom and the distal boom by transmitting the wire to the wire extended between the proximal boom and the distal boom via the sheave, the installation of the sheave provided at the appropriate position of the intermediate boom. As shown in FIG. 4, the boss 2B in which the recess 33 is provided inside the through hole 32 provided in the intermediate boom 2 as shown in FIG.
Is welded, and one end of a shaft 35 on which a sheave 37 is rotatably mounted is fitted into the recess 33 of the boss 2B.
The boss 2 is inserted into the bolt hole 35Z formed at one end of the shaft 35.
A sheave mounting structure for a multi-stage telescopic boom is provided in which the sheave 37 is mounted between the tip boom 3 and the intermediate boom 2 by inserting and screwing a bolt 36 formed so as to penetrate into the recess 33 from the outside of B. It is publicly known (see Japanese Utility Model Publication No. 4-16790).

[0003]

However, in such a sheave mounting structure, when the sheave is assembled, the distance between the inside of the boss and the outside of the tip boom 3 must be equal to or greater than the length of the shaft 35. If this interval is large, the tip boom will have a much smaller cross-sectional area than the intermediate boom, and the strength will decrease.
Therefore, in order to secure the required strength of the tip boom, it is uneconomical to make the cross-sectional areas of the intermediate boom and the base boom too large. Therefore, there is a demand for a sheave mounting structure capable of incorporating the sheave even if the gap between the tip boom and the intermediate boom is narrow.

The present invention solves such a problem in the sheave mounting structure of the multi-stage telescopic boom, and the sheave can be incorporated even if the gap between the tip boom and the intermediate boom is narrowed, and the tip boom's An object of the present invention is to provide a sheave mounting structure capable of expanding the cross-sectional area and improving the strength.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an intermediate boom is inserted into a base boom, and a distal boom is inserted into the intermediate boom.
A telescopic hydraulic cylinder is provided between the proximal boom and the intermediate boom, and one end is fixed to the distal boom and the other end is fixed to the proximal boom. In a multi-stage telescopic boom that is attached to the boom, insert an extension sheave that has a detent pin with a bolt hole at the outer end and a flange at the inner end into the shaft hole in advance, insert it into the gap between the tip boom and the intermediate boom, and stop the detent. Insert the sheave shaft with the pin hole for inserting the pin and the bolt insertion hole into the shaft hole of the extension sheave from the outside of the intermediate boom, and screw the bolt into the bolt hole of the rotation stop pin from the outside of the sheave shaft. The above problem is solved by adopting a sheave mounting structure for wearing and fixing the sheave shaft to the intermediate boom.

[0006]

[Operation] Since the sheave shaft is fitted from the outside of the intermediate boom, the distance between the tip boom and the intermediate boom when the extension sheave is attached may be such that the extension sheave can be inserted. It is possible to narrow the gap with the intermediate boom and increase the cross-sectional area of the tip boom.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of the construction of a three-stage boom equipped with a sheave mounting structure according to an embodiment of the present invention, FIG. 2 is a sectional view showing the mounting structure of an extension sheave, and FIG. It is a front view of a sheave for use. The three-stage boom B is a telescopic boom for an aerial work vehicle, and the intermediate boom 2 and the distal boom 3 are sequentially fitted in the base boom 1 in a telescopic manner.
A bucket 17 is attached to the tip of the boom B.

An end of a piston rod 5 of a hydraulic cylinder 4 for expansion and contraction is connected to a base end of the base boom 1, and a cylinder tube 6 of the hydraulic cylinder 4 is connected to a base end of the intermediate boom 2. The piston rod side of is connected.
An extension sheave 7 is attached to the tip end of the intermediate boom 2, and an extension wire rope 8 having one end fixed to the base end portion of the tip boom 3 is hooked around the extension sheave 7. The other end of the extension wire rope 8 is fixed to the base end of the base boom 1. A reduction sheave 9 is attached to the base end portion of the intermediate boom 2, and a reduction wire rope 10 having one end fixed to the base end portion of the tip boom 3 is hung on the reduction sheave 9. The other end of the reduction wire rope 10 is rotated and fixed to the tip of the base boom 1.

Further, a plurality of sheaves 11 for hoses are attached to the base end of the intermediate boom 2. A hose 13, one end of which is connected to a fixing member 12 at the tip of the base boom 1, is hooked around the hose sheave 11.
Has its other end connected to a fixing member 14 at the tip of the tip boom 3. Fixing bracket 12 at the tip of the base boom 1
A fixed pipe 15 is connected to a hydraulic pressure source (not shown). In addition, a hose 16 for supplying hydraulic oil to an actuator (not shown) of various working devices mounted on the bucket 17 is provided on the fixing fitting 14 at the tip of the tip boom 3.
Is connected.

When the hydraulic cylinder 4 is extended during boom extension, the intermediate boom 2 extends relative to the base end boom 1. At the same time, the extension sheave 7 advances and the tip boom 3 connected to the extension wire rope 8 moves to the intermediate boom 2.
To stretch. When the hydraulic cylinder 4 is contracted during the boom contraction, the intermediate boom 2 contracts with respect to the base end boom 1. At the same time, the reduction sheave 9 moves backward, and the tip boom 3 connected to the reduction wire rope 10 contracts with respect to the intermediate boom 2.

Here, the mounting structure of the extension sheave 7 to the intermediate boom 2 is, as shown in FIGS. 2 and 3, an outer end (FIG. 2).
Insert the extension sheave 7 in which the rotation stop pin 20 having the bolt hole 21 at the upper right end) and the flange 22 at the inner end is previously assembled in the shaft hole 23 into the gap between the tip boom 3 and the intermediate boom 2,
A sheave shaft 26 having a pin hole 24 into which the locking pin 20 is inserted and a bolt insertion hole 25 is fitted into the shaft hole 23 of the extension sheave from the outside of the intermediate boom. The stopper pin 20 and the sheave shaft 26 are
The coupling bolt 27 is screwed into the bolt hole 21 of the detent pin 20 from the outside of the shaft, and the sheave shaft 26 is fixed to the fixing bolt 2.
It is fixed to the intermediate boom 2 at 8.

In this structure, the length of the detent pin 20 previously assembled in the shaft hole 23 can be set to be equal to or less than the width of the extension sheave 7, and the sheave shaft 26 is fitted from the outside of the intermediate boom 2. Therefore, the distance between the tip boom 3 and the intermediate boom 2 at the time of attaching the extension sheave 7 may be any distance as long as the extension sheave 7 can be inserted, and the gap between the tip boom 3 and the intermediate boom 2 can be set. The tip boom 3 can be made narrower and the cross-sectional area of the tip boom 3 can be increased.

[0013]

As described above, according to the sheave mounting structure of the present invention, the sheave can be incorporated even if the gap between the tip boom and the intermediate boom is narrowed, and the cross sectional area of the tip boom can be reduced. It can be expanded and its strength can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of a three-stage boom equipped with a sheave mounting structure according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a mounting structure for the extension sheave.

FIG. 3 is a front view of the extension sheave.

FIG. 4 is a cross-sectional view showing a conventional sheave mounting structure.

[Explanation of symbols]

 1 Base End Boom 2 Middle Boom 3 End Boom 4 Hydraulic Cylinder 5 Piston Rod 6 Cylinder Tube 7 Extension Sheave 8 Extension Wire Rope 9 Reduction Sheave 10 Reduction Wire Rope 20 Lock Pin 21 Bolt Hole 22 Flange 23 Shaft Hole 24 Pin hole 25 Bolt insertion hole 26 Sheave shaft 27 Coupling bolt 28 Fixing bolt B Boom

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B66F 9/08 F 7515-3F 9/22 V 7515-3F 11/04

Claims (1)

[Claims] 1. An intermediate boom is inserted into the proximal boom and a distal boom is inserted into the intermediate boom in order, a hydraulic cylinder for expansion and contraction is provided between the proximal boom and the intermediate boom, and one end is fixed to the distal boom. , A multi-stage telescopic boom that attaches an extension sheave that hangs an extension wire rope that fastens the other end to the base boom and attaches the extension sheave to the intermediate boom, and installs a detent pin with a bolt hole at the outer end and a flange at the inner end in advance. Insert the extension sheave incorporated in the hole into the gap between the tip boom and the intermediate boom,
A sheave shaft having a pin hole for inserting the detent pin and a bolt insertion hole is fitted into the shaft hole of the extension sheave from the outside of the intermediate boom, and the bolt hole of the detent pin is provided from the outside of the sheave shaft. A sheave mounting structure for a multi-stage telescopic boom, which is characterized in that bolts are screwed to the and the sheave shaft is fixed to the intermediate boom.