JP2552161Y2 - Boom telescopic device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom extension device.

[0002]

2. Description of the Related Art A conventional boom extension / contraction device of this type is shown in FIG.
And it is comprised as shown in FIG. Boom A
The boom is composed of a base boom 2, an intermediate boom 3, and a front boom 4. Each boom is a rectangular tube, and is arranged on the base 1 in a vertical posture. The base boom 2 has its base end fixed to the base 1, the intermediate boom 3 is inserted into the base boom 2,
A slide plate (not shown) that slides on the outer surface of the intermediate boom 3 is arranged inside the distal end of the base boom, and a slide plate (not shown) that slides on the inner surface of the base boom 2 is disposed outside the base end of the intermediate boom 3. The intermediate boom 3 is configured to be extendable and retractable with respect to the base boom 2. A slide plate (not shown) that inserts the leading boom 4 into the middle boom 3 and slides on the outer surface of the leading boom 4 inside the tip of the middle boom 3
And a slide plate (not shown) that slides on the inner surface of the intermediate boom 3 is disposed outside the base end of the front boom 4 so that the front boom 4 can extend and contract with respect to the intermediate boom 3.

[0003] A hydraulic cylinder 5 is interposed between the base boom 2 and the intermediate boom 3, and the hydraulic cylinder 5 is driven to expand and contract, so that the intermediate boom 3 can be expanded and contracted with respect to the base boom 2. The sheaves 6a, 6
b are arranged in a pair. This pair of sheaves 6a, 6b
Is an intermediate boom 3 in plan view as shown in FIG.
Are disposed on the left and right sides on the outer upper side of the rectangular tube. Sheave 6
a, 6b, one end of which is engaged with the base end of the boom 4 and the other end of which is engaged with the sheave 6a, 6b at the distal end of the base boom 2 after the elongation. Two sets of ropes 9 a and 9 b are arranged between the leading boom and the base boom 2. Here, the locking 7a, 7b at the base end of the tip boom 4
Is composed of a folding guide 12 disposed on the upper side of the base end of the front boom 4, and the extension ropes 9a and 9b are composed of substantially one rope. The latches 8a and 8b at the distal end of the base boom 2 are locked to the bracket 10 disposed on the upper outer side of the distal end of the base boom 2 using a screw mechanism so that the tension thereof can be adjusted. Therefore, by extending the hydraulic cylinder 5, the intermediate boom 3 is extended from the base boom 2 and the boom 4 is extended from the intermediate boom 3 at the same time.

[0004] At the base end of the intermediate boom 3 is a sheave 10a,
10b are arranged in a pair. This pair of sheaves 10a,
As shown in FIG. 6, 10b is disposed on the outer lower side of the rectangular tube of the intermediate boom 3 on the left and right in plan view. One end of each of the sheaves 10a and 10b is engaged with the base end of the boom 4 and the other end is connected to the sheave 10a.
a and 10b are locked to the tip of the base boom 2 after the passage of 12b.
Two pairs of reduction ropes 13a and 13b to be 12b are arranged between the leading boom and the base boom 2. Here, the locking 11a, 11b at the base end of the front boom 4 is constituted by a folding guide 13 arranged on the lower side of the base end of the front boom 4, and the reduction ropes 13a, 13b are substantially one. It consists of ropes. Locking 12a, 1 at the tip of base boom 2
Reference numeral 2b denotes a bracket 11 arranged on the upper side inside the distal end portion of the base boom 2 which is engaged with the brackets 12a and 12b using a screw mechanism so that the tension thereof can be adjusted. Therefore, by reducing the hydraulic cylinder 5, the intermediate boom 3 is reduced from the base boom 2 and the boom 4 ahead of the intermediate boom 3 is reduced at the same time.

[0005] In the conventional boom extension / contraction device constructed as described above, the intermediate boom 3 is moved from the base boom 2 to the boom 4 by driving the hydraulic cylinder 5 to extend and retract.
At the same time. Such a boom telescopic device can be used as a telescopic lighting tower by attaching lighting equipment to the tip of the boom 4, or by placing the boom on a vehicle and attaching a bucket directly or via an arm to the tip of the boom 4. It is used as a telescopic boom for work platforms.

[0006]

However, the boom extension and contraction device configured as described above has the following problems. That is, the tip boom 4 includes the extension rope 9a,
9b, the upper end of the base end of the boom 4 is supported by the folding guide 12 (locking 7a, 7b).
Acting as an eccentric load on the leading boom 4, the sliding resistance of the slide plate disposed between the leading boom 4 and the intermediate boom 3 increases, so that the leading boom 4 cannot be smoothly extended and retracted, and only the boom is extended and contracted. (In other words, no load is applied to the boom, which means no load), the output of the hydraulic cylinder 5 is required more than necessary. It is an object of the present invention to provide a new boom extension and contraction device that solves the above problems.

[0007]

Means for Solving the Problems To achieve the above object, the boom extension and contraction device of the present invention has an intermediate boom inserted into a base boom and a front boom inserted into an intermediate boom so as to extend and contract sequentially.
A hydraulic cylinder is interposed between the base boom and the middle boom, and a pair of sheaves are arranged at the tip of the middle boom, and one side of the sheave is locked to the base end of the front boom, and the other side is passed through the sheave. A boom in which two sets of extension ropes to be locked on the base boom side are arranged between the leading boom and the base boom, and the hydraulic boom is extended so that the intermediate boom extends from the base boom simultaneously with the boom ahead of the intermediate boom. In the telescopic device, the pair of sheaves are arranged at the distal end of the intermediate boom so as to be substantially opposed to each other and centered on the telescopic center axis of the boom, and one end of each of the two sets of extension ropes is a base end of the front boom. The locking portions that lock with each other, and the locking portions that lock the other side of the two sets of elongating ropes with the base boom side are positioned substantially symmetrically with respect to the center axis of the boom. Is characterized in that aged two sets of elongated rope that passes a serial pair of sheaves opposite to each other are arranged.

[0008]

The boom telescopic device of the present invention constructed as described above has a pair of sheaves arranged at the tip of the intermediate boom so as to be substantially opposed to each other about the telescopic center axis and parallel to each other. Each of the locking portions, one side of which engages with the base end portion of the front boom, and the locking portion, on which the other side of each of the two sets of extension ropes locks with the base boom side, is a center axis of the telescopic boom. Since the two sets of extension ropes passing through the pair of sheaves are made to pass in opposite directions so as to be substantially symmetrical with respect to each other, the extension rope is supported so that the load is uniformly applied to the leading boom. And the unbalanced load can be prevented. Accordingly, a smooth extension / retraction operation of the boom can be obtained, and when only the boom is extended / contracted, the output of the hydraulic cylinder 5 is not required more than necessary.
Thus, the boom can be driven to expand and contract with a relatively small hydraulic cylinder.

[0009]

FIG. 1 shows a boom extension and contraction device according to the present invention.
3 will be described below. B is a boom, a base boom 21, an intermediate boom 22, and a leading boom 2
3, each boom is a square tube and is arranged on the base 20 in a vertical posture. The base boom 21 has its base end fixed to the base 20, the intermediate boom 22 is fitted over the base boom 21,
A slide plate (not shown) that slides on the inner surface of the intermediate boom 22 is disposed outside the distal end portion of the base boom 21, and a slide plate (not shown) that slides on the outer surface of the base boom 21 is disposed inside the base end of the intermediate boom 22. Thus, the intermediate boom 22 is configured to be extendable and retractable with respect to the base boom 21. The front boom 23 is externally fitted to the intermediate boom 22, and a slide plate (not shown) that slides on the inner surface of the front boom 23 is disposed outside the front end of the middle boom 22.
A slide plate (not shown) that slides on the outer surface of the intermediate boom 22 is disposed inside the base end of the intermediate boom 22.
On the other hand, the tip boom 23 is configured to be able to expand and contract.

A hydraulic cylinder 25 is interposed between the base boom 21 and the intermediate boom 22, and the intermediate boom 22 can be extended and contracted with respect to the base boom 21 by driving the hydraulic cylinder 25 to extend and contract. Particularly in the case of this embodiment, the rod end side of the hydraulic cylinder 25 is mounted on the base 20, the cylinder side from the rod side end is mounted on the base end of the intermediate boom 21, and the hydraulic cylinder 25 is inverted. . The end of the rod is not attached to the base boom 21 and the base 2
The mounting at 0 is performed because it is more convenient to position the rod end on the base 20 side when oil is supplied to the hydraulic cylinder 25 from the rod side end. Therefore, the rod-side end of the hydraulic cylinder 25 may be attached to the base boom 21 without being attached to the base 20.

Reference numerals 26a and 26b are a pair of sheaves arranged at the tip of the intermediate boom 22. This pair of sheaves 2
6a and 26b are in plan view as shown in FIG.
A pair of brackets 30a, 30b laid on the intermediate boom 22 in parallel with the cylinder side of the intermediate boom 22,
2 are supported and arranged by the pivot shafts 31a and 31b. The pivot shafts 31a and 31b are substantially opposed to each other about a center axis C of the boom, and are biased toward the corner of the intermediate boom 22. That is, this sheave 26a, 2
6b, the one-side rope passing through the sheaves 26a and 26b is located in the base boom 21, and the other-side rope passing through the sheaves 26a and 26b is connected to the leading boom 23 and the intermediate boom 22.
They are arranged so as to be located between them, and are arranged substantially parallel to each other with the center axis C of the boom extending and contracting substantially at the center.

Reference numerals 29a and 29b are extension ropes.
27a, one end of the extension rope 29a is
This is a locking portion for locking the tension of the bracket 32a arranged at the tip of the bracket 32a using a screw mechanism so as to be adjustable. 2
Reference numeral 8a denotes a locking portion for locking the other side of the extension rope 29a to the base end of the base boom 21 using a screw mechanism.
27b, one end of the extension rope 29b is
This is a locking portion that locks the tension of the bracket 32b arranged at the tip of the bracket 32b using a screw mechanism so as to be adjustable. 2
Reference numeral 8b denotes a locking portion for locking the other side of the extension rope 29b to the base end of the base boom 21 using a screw mechanism.
The extension ropes 29a and 29b passing through the sheaves 26a and 26b are made to pass in opposite directions so that the locking portions are located at substantially symmetrical positions with respect to the extension / contraction axis C of the boom. That is, in plan view, as shown in FIG. 2, the elongation rope 29 a is moved from the right (locking portion 27 a) to the left (locking portion 28 a).
While the elongating rope 29b is moved from the left (locking portion 27b) to the right (locking portion 28).
The sheave 26a is passed in b).

A sheave 33 is located between the leading boom 23 and the intermediate boom 22 and is attached to the base end of the intermediate boom 22 by a pivot 34. Reference numeral 35 denotes a reduction rope, one end of which is locked 37 so that the tension thereof can be adjusted to the tip of the boom 23 by a bracket 36 provided at the tip of the boom 23 and a screw mechanism. Are locked to the distal end of the base boom 21 by a bracket and a screw mechanism (not shown).

The boom extension and contraction device of the present invention configured as described above operates as follows. That is, the intermediate boom 22 and the leading boom 23 are simultaneously extended and retracted with respect to the base boom 21 and the intermediate boom 22 by driving the hydraulic cylinder 25 to extend and contract, respectively.
b is disposed at the tip of the intermediate boom 22 so as to be substantially opposed to and parallel to the center axis C of the telescopic center.
a and 29b are engaged with the base end of the boom 23, and the other side of each of the two sets of extension ropes 29a and 29b is engaged with the base boom 21. Each locking portion 28a, 28b to be stopped
Is obtained by passing two pairs of extension ropes 29a and 29b passing through the pair of sheaves 26a and 26b in opposite directions so as to be substantially symmetrical with respect to the center axis C of the boom. The tip boom 23 can be supported by the extension ropes 29a and 29b so that the load is evenly applied to the extension 23, so that an unbalanced load can be prevented. Therefore, a smooth expansion and contraction operation of the tip boom 23 is obtained,
When only the boom is expanded and contracted, the output of the hydraulic cylinder 25 is not required more than necessary. Thus, the boom can be driven to expand and contract with a relatively small hydraulic cylinder.

In the above-described embodiment, the boom B is connected to the base boom 21, the intermediate boom 22, and the intermediate boom 22 to the first boom 2.
3 are externally fitted one after another, but it is needless to say that the same can be implemented by internally fitting like the boom A described in the prior art. Further, in the above-described embodiment, the two sets of the extension ropes 29a and 29b are described as two ropes. However, as described in the related art, the extension ropes 29a and 29b may be configured with a single rope using a folded sheave. Of course. Further, in the above embodiment, only one set of the reducing ropes 35 is arranged, but it is needless to say that the embodiment can be practiced when two sets of the reducing ropes 35 are arranged. Next, in the above embodiment, the pair of sheaves 26a and 26b arranged at the tip end of the intermediate boom 22 are arranged in parallel with the angular boom, but as shown in FIG. However, it may be arranged diagonally on the square boom.

[0016]

According to the boom extension and contraction device of the present invention constructed as described above, the leading boom can be supported by the extension rope so that the load is evenly applied, and the uneven load can be prevented. Accordingly, a smooth extension and retraction operation of the leading boom is obtained, and when only the boom is extended or contracted, the output of the hydraulic cylinder 25 is not required more than necessary. Thus, the boom can be driven to expand and contract with a relatively small hydraulic cylinder.

[Brief description of the drawings]

FIG. 1 is an explanatory view illustrating a boom extension and contraction device of the present invention.

FIG. 2 is an explanatory view for explaining the boom extension and contraction device of the present invention, and is an enlarged view taken along line XX of FIG. 1;

FIG. 3 is an explanatory view for explaining the boom extension and contraction device of the present invention, and is a view taken along the line YY of FIG. 1;

FIG. 4 is an explanatory view illustrating another embodiment of the boom extension device of the present invention.

FIG. 5 is an explanatory view illustrating a conventional boom extension / contraction device.

FIG. 6 is an explanatory view for explaining a conventional boom extension / contraction device;
FIG. 7 is an enlarged plan view of FIG. 6.

[Explanation of symbols]

 21 Base Boom 22 Intermediate Boom 23 Front Boom 25 Hydraulic Cylinder 26a Sheave 26b Sheave 27a Locking Part 27b Locking Part 29a Extension Rope 29b Extension Rope C

Claims (1)

(57) [Scope of request for utility model registration] 1. An intermediate boom is inserted into the base boom so that the front boom can be extended and contracted sequentially into the intermediate boom, a hydraulic cylinder is interposed between the base boom and the intermediate boom, and a pair of sheaves is arranged at a tip end of the intermediate boom. In addition, two sets of elongation ropes, one of which is locked to the base end of the boom and the other side is locked to the base boom after the sheave has passed, are arranged in two sets between the front boom and the base boom. An extension device for a boom, in which a middle boom is extended from a base boom and a boom ahead of an intermediate boom is simultaneously extended by extending a cylinder. Each of the two sets of elongation ropes are arranged in parallel to face each other, and one side of each of the two sets of elongation ropes is engaged with the base end of the leading boom, and the other side of each of the two sets of elongation ropes is front. The two sets of elongation ropes passing through the pair of sheaves are arranged so as to be opposite to each other so that the locking portions to be locked on the base boom side are substantially symmetrical with respect to the center axis of the boom. Characteristic boom telescopic device.