JPH07115830B2 - Crane crane boom telescope - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a boom telescopic device for a mobile crane having a plurality of stages of telescopic booms.

(Prior Art) Conventionally, there is a crane vehicle in which a crane boom is mounted on a freely movable vehicle body so that the boom can be extended and retracted in multiple stages by a hydraulic cylinder and a telescopic rope (for example, Japanese Patent Application No. 2-10582). ).

In the conventional crane vehicle, the boom is constructed as shown in FIG. 5, and the boom is expanded and contracted in, for example, five stages by controlling the expansion and contraction of two hydraulic cylinders by the hydraulic circuit shown in FIG. Has become.

That is, the boom is composed of a first boom a, a second boom b, a third boom c, a fourth boom d and a fifth boom e, and a two-stage telescopic unit is provided between the first boom a and the second boom b. The cylinder f is provided with four-stage telescopic cylinders g between the third boom c and the fourth boom d, respectively.
The booms c are connected to each other by extension ropes j and reduction ropes k that bypass the extension sheaves h and the reduction sheaves i provided at the front and rear ends of the second boom b, respectively.
The fifth boom e and the fifth boom e are connected by an extension rope n and a reduction rope o that bypass the extension sheave 1 and the reduction sheave m provided at the front and rear ends of the fourth boom d, respectively.

Then, by supplying the hydraulic pressure from the hydraulic pump p shown in FIG. 6 to each of the two-stage telescopic cylinders f and the four-stage telescopic cylinders g via the telescopic control valve s, each boom is extended or contracted sequentially. It is like this.

(Problems to be Solved by the Invention) In the above-described conventional boom telescopic device, a pipe is provided in the boom to supply hydraulic pressure to a four-stage telescopic cylinder g provided between the third boom c and the fourth boom d. A long hose r was used.

For this reason, it is necessary to provide the hose reel q and to feed or wind the hose r from the hose reel q every time the boom expands and contracts, which requires a complicated structure of the hose reel q, requires a large space, and is expensive. There was a drawback.

The present invention has been made with the object of remedying the above-mentioned drawbacks.
An object of the present invention is to provide a boom telescopic device for a crane vehicle that enables a hose to be processed by a sheave having a simple structure.

(Means and Actions for Solving the Problems) In order to achieve the above object, the present invention provides a three-stage telescopic cylinder between a second boom and a third boom of a boom that telescopes in multiple stages, and a third boom. By installing a 4-stage telescopic cylinder between the 4th boom and the 4th boom, and connecting the hose piped in the boom to the 3-stage telescopic cylinder by bypassing the hose sheave provided in the 2nd boom, Hydraulic pressure is supplied to the 4-stage telescopic cylinder through the cylinder and the piston rod of the 4-stage telescopic cylinder, and a reducing sheave provided between the first beam and the third boom at the front and rear ends of the second boom. And a reduction rope and extension rope that bypass the extension sheave and are connected to each other.

Thus, by expanding and contracting the three-stage telescopic cylinder and the four-stage telescopic cylinder, the second boom projects from the rear end of the first boom when the boom is retracted, so that a boom overhang amount can be reduced. it can.

Further, since the hose is processed by using the telescopic cylinder in sequence and the hose sheave provided in the second boom when the boom is expanded and contracted, it is not necessary to separately provide a hose reel for winding a long hose.

(Embodiment) An embodiment of the present invention will be described in detail with reference to the drawings shown in FIGS. 1 to 4.

FIG. 1 shows a mobile crane, in which an upper revolving structure 3 is rotatably provided on a lower traveling structure 1 which can be driven by wheels 2, and a boom 4 which expands and contracts in five stages, for example, on the upper revolving structure 3. Is provided by a boom cylinder 5 so that it can be raised and lowered.

The boom 4 is first boom as shown in Figure 2 4 ₁ and second
Boom 4 ₂ , 3rd boom 4 ₃ , 4th boom 4 ₄ and 5th boom
4 ₅ with a 3-stage telescopic cylinder 6 between the second boom 4 ₂ and the third boom 4 ₃ , and a third boom 4 ₃ and a fourth boom 4 ₄
A four-stage expansion / contraction cylinder 7 is provided between them.

Fig. 3 is a detailed view of the upper 3rd and 4th stage telescopic cylinders 6 and 7. The 3rd stage telescopic cylinder 6 has a piston 6b inside a cylinder 6a.
Is housed in the piston 6b, and the piston 6b has a hollow piston rod 6c.
One end of is stuck.

The other end of the piston rod 6c are projected through the end plate 6d outside cylinder 6a, the tip is pivotally connected to the second boom 4 ₂ on the base end side by the pin 9.

A valve block 10 is provided on one end side of the cylinder 6a of the two-stage telescopic cylinder 6, and the valve block 10
Together with part is pivotally connected to the third boom 4 ₃ on the base end side by the pin 11, the counterbalance valve 12a and a mechanical check valve 12b is furnished respectively to the valve block 10.

The hydraulic pressure supplied from the hydraulic pump 13 via the expansion / contraction control valve 14 is supplied to the counter balance valve 12a from the hoses 15 and 16 arranged in the boom 4.

The hydraulic pressure supplied from the hose 15 to the counterbalance valve 12a is the end plate 6h provided on the other end side of the cylinder 6a from the conduit 6g.
It is supplied to the bottom side chamber 6i of the cylinder 6a through the mechanical check valve 17 therein, and partly flows into the bottom side chamber 7e of the cylinder 7c from the mechanical check valve 12b through the piston rod 7b of the 4-stage expansion / contraction cylinder 7. It is like this.

Further, the hydraulic pressure supplied from the hose 16 to the counter balance valve 12a flows into the rod side chamber 6f of the cylinder 6a through the through hole 6e, and a part of the oil pressure passes through the piston rod 7a of the 4-stage expansion / contraction cylinder 7 to the rod side chamber of the cylinder 7c. It is designed to flow into 7d.

The piston rods 7a and 7b of the four-stage telescopic cylinder 7 have a hollow double structure, one end of which is fixed to the valve block 10 and the other end of which is fixed to the piston 7f housed in the cylinder 7c. Has been done.

Further, when the rod 6c of the three-stage telescopic cylinder 6 is fully extended, the cam portion 6j of the piston portion is mechanically checked by the mechanical check valve 12
While switching b, at the other end of the cylinder 7c, when the 4-stage telescopic cylinder 7 is contracted, the end plate of the 3-stage cylinder 6
An operating rod 20 for switching a mechanical check valve 17 provided in 6h is attached via a bracket 7g.

The piping of the above-mentioned three-stage and four-stage telescopic cylinders 6 and 7 is shown in FIG.

On the other hand, between the first boom 4 ₁ and the third boom 4 ₃ of the boom 4, the reduction rope is provided when bypassing the reduction sheave 24 and the extension sheave 25 provided at the front and rear ends of the second boom 4 _2.
26 and a rope 27 for extension.

In addition, a space between the third boom 4 ₃ and the fifth boom 4 ₅ is provided by an extension rope 30 and a reduction rope 31 which bypass the extension sheave 28 and the reduction sheave 29 provided at the front and rear ends of the fourth boom 4 ₄ , respectively. It is connected.

Next, the operation will be described. In the retracted state of the boom 4, the first
As shown in the figure, the rear end of the second boom 4 ₂ projects rearward from the rear end of the first boom 4 ₁ .

In addition, the expansion / contraction control valve 14 is used to extend the boom from the retracted state.
Is operated in the extension direction, the hoses 15, 16 of the hydraulic pump 13
Since has bypasses Hosushibu 30 provided in the second beam 4 in _2, the expansion and contraction of hose 15, 16 can be processed in the second boom 4 within _2, a hose for handling a hose 15, 16 The reel is unnecessary.

On the other hand, when the expansion / contraction control valve 14 is operated toward the contraction side to contract the expanded boom 4, the hydraulic pressure of the hydraulic pump 13 causes the rod side chamber 6f of the 3-stage expansion / contraction cylinder 6 and the rod-side chamber of the 4-stage expansion / contraction cylinder 7 from the pipe 16. Supplied to 7d respectively.

As a result, the three-stage and four-stage telescopic cylinders 6 and 7 are contracted, so that they are pulled by the contracting ropes 26 and 31 and the second boom 4 is pulled.
_{The second} and fifth booms 4 ₅ also follow the _third and fourth booms 4 ₃ and 4 ₄ and are gradually reduced in size.

(Effects of the Invention) As described in detail above, the present invention includes a three-stage telescopic cylinder and four
Hydraulic pressure is supplied because the hydraulic pressure supplied to the 3-stage telescopic cylinder via the hose is connected to the 4-stage telescopic cylinder and is supplied to the 4-stage telescopic cylinder through the piston rod of the 4-stage telescopic cylinder. The hose can be processed by simply bypassing the sheave provided in the second boom, and does not require a hose reel having a complicated structure as in the past.

As a result, the mechanism for processing the hose can be simplified without taking up space, so that the vehicle body can be made compact and more inexpensive.

[Brief description of drawings]

1 is a side view of a mobile crane showing an embodiment of the present invention, FIG. 2 is a sectional view of a boom, FIG. 3 is an enlarged sectional view of a telescopic cylinder, FIG. 4 is the same circuit diagram, and FIG. 6 and 6 are conventional explanatory views. 4 …… Boom, 4 ₁ …… First boom, 4 ₂ …… Second boom, 4 ₃ …… 3rd boom, 4 ₄ …… 4th boom, 6 …… 3-stage telescopic cylinder, 7 …… 4 Step extension cylinder, 7a, 7b …… Piston rod, 24 …… Reduction sheave, 25 …… Extension sheave, 26 …… Reduction rope, 27 …… Extension rope,

Claims (1)

[Claims] 1. A vehicle in which a second boom protrudes from a rear end of the first boom during traveling to reduce a boom overhang amount, and between the second boom 4 ₂ and the third boom 4 ₃ of the boom 4 which expands and contracts in multiple stages. A three-stage telescopic cylinder 6 and a four-stage telescopic cylinder 7 are provided between the third boom 4 ₃ and the fourth boom 4 ₄ and these cylinders have a telescopic operating mechanism in sequence and inside the boom 4. by connecting a hose 15 and 16 piping 3 step telescopic cylinder 6 by bypassing the Hosushibu 30 provided on the second boom 4 within ₂ to 3-stage telescopic cylinder 6
And through the piston rods 7a, 7b of the four-stage telescopic cylinder 7 to supply hydraulic pressure to the four-stage telescopic cylinder 7, respectively, and between the first beam 4 ₁ and the third beam 4 ₃ the second boom 4 A boom telescopic device for a crane vehicle, which is connected by a reduction rope 26 and an extension rope 27 that bypass the reduction sheave 24 and the extension sheave 25 provided at the front and rear ends of ₂ .