JP2567978Y2 - Multi-stage telescopic boom - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage telescopic boom mounted on an aerial work vehicle or a crane truck.

[0002]

2. Description of the Related Art As shown in FIG. 3, for example, the above-mentioned multistage telescopic boom is mounted on a base B so as to be able to move up and down, and a second boom 31 is inserted into the first boom 31 so as to be telescopic. A boom 32, a third boom 33 inserted into the second boom 32 so as to be extendable and contractable, and a fourth boom 34 inserted into the third boom 33 so as to be extendable and contractible are formed in a telescope shape. Such a multi-stage telescopic boom 30
In the above, the expansion and contraction operation of the second boom 32 with respect to the first boom 31 is performed by the expansion and contraction operation of the hydraulic cylinder 35 attached therebetween, but the expansion and contraction operation between the other booms is performed by winding the sheave and This is performed by a wire mechanism including a wire to be hung. For example, as shown in the figure, a reduction wire mechanism for performing the reduction operation of the multi-stage telescopic boom 30 is attached to the base end of the second boom 32, and the distal end of the first boom 31 and the third boom 33. 41 attached between the proximal ends of
And a wire 42 attached to the proximal end of the third boom 33 and attached between the distal end of the second boom 32 and the proximal end of the fourth boom 34. And a fourth boom reduction sheave 44.

[0003] In the multi-stage telescopic boom 30 having such a reducing wire mechanism, when the second boom 32 is reduced with respect to the first boom 31 by the extension and contraction operation of the hydraulic cylinder 35, the third boom is moved together with the second boom 32 to the third boom. The third boom 33 is moved to the first position while the boom reduction sheave 43 moves in the proximal direction.
The boom 31 is pulled and reduced. Similarly, when the third boom 33 is reduced with respect to the second boom 32, the fourth boom reduction sheave 44 together with the third boom 33 is provided.
Pulls and reduces the fourth boom 34 with respect to the third boom 33 while moving in the proximal direction. In this manner, the entire multi-stage telescopic boom 30 can be reduced by one hydraulic cylinder 35, which is effective for reducing the weight of the multi-stage telescopic boom 30 and the like.

[0004]

However, in the above-described multistage telescopic boom 30, a counterbalance valve (which controls hydraulic oil so as to smoothly expand and contract the hydraulic cylinder) is provided inside the base end of the first boom 31. A hydraulic oil control device 38 is attached. For this reason, a state where the third boom 33 is excessively reduced with respect to the second boom 32, for example, such that the fourth boom reduction sheave 44 is located in the proximal direction beyond the third boom reduction sheave 43. If the second boom 32 is completely reduced relative to the first boom 31 in this state, the fourth boom reduction sheave 44 may interfere with the counter balance valve 38. Therefore, conventionally, in order to prevent such interference, the third boom 33 is used.
Of the second boom 32 is restricted. further,
Since there is a possibility that the fourth boom reducing sheave 44 and the fourth boom may interfere with each other, the reduction of the fourth boom with respect to the third boom is also limited, and the length of the multi-stage telescopic boom 30 in the fully contracted state according to those restrictions. There is a problem that can not be shortened. Thus, for example, when a multi-stage telescopic boom having a required length at full extension is mounted on a truck cabback in a fully contracted state, the tip of the multi-stage telescopic boom protrudes forward or rearward of the vehicle body. However, there is a problem that mounting becomes difficult.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a multistage telescopic boom capable of shortening a boom length in a fully contracted state as much as possible.

[0006]

In order to achieve the above object, in the multistage telescopic boom of the present invention, a fourth boom reduction sheave is provided above or below the hydraulic oil control device inside the base end of the first boom. When the multistage telescopic boom is fully reduced by forming a storage space to fit therein, the fourth boom reduction sheave is located closer to the base end than the third boom reduction sheave and is stored in the storage space. doing.

[0007]

In such a multistage telescopic boom, the third boom is reduced with respect to the second boom until the fourth boom reducing sheave is located in the proximal direction beyond the mounting position of the third boom reducing sheave. Even if the second boom is completely reduced with respect to the first boom in this state, the fourth boom reduction sheave is stored in a storage space formed above or below the hydraulic oil control device and interferes with the hydraulic oil control device. I will not do it. Therefore, the third boom can be sufficiently reduced with respect to the second boom, and the boom length in the fully contracted state of the multistage telescopic boom can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a crane truck 1 having a multi-stage telescopic boom according to the present invention.
The crane truck 1 is configured with a truck as a base, and a turntable 3 that can freely turn horizontally with respect to the cabback 2 is attached to a front portion of the cabback 2. The multistage telescopic boom 10 is attached to an upper portion of the swivel base 3. This multi-stage telescopic boom 10
Is a first boom 11 pivotally attached to the swivel 3 so as to be able to move up and down.
And a second boom 12 inserted into the first boom 11 so as to extend and contract toward its distal end, and a third boom 13 inserted into the second boom 12 and extendable and contractable toward the distal end thereof. And a fourth boom 14 which is inserted into the third boom 13 so as to be able to expand and contract toward the distal end thereof, to form a telescope. A hook 4 is suspended from the tip of the fourth boom 14, and it is possible to lift a heavy object through the lifting and lowering of the hook 4, the turning operation of the swivel base 3, and the undulating / extending and retracting operation of the multi-stage telescopic boom 10. it can.

Next, referring to FIG. 2, the multistage telescopic boom 1 will be described.
The reduction wire mechanism among the 0 expansion mechanisms will be described. A hydraulic cylinder 15 that extends and contracts the second boom with respect to the first boom 11 is attached to the base end of the first boom 11 and the base end of the second boom 12. In the hydraulic cylinder 15, the distal end of the piston rod 15 a is attached to the proximal end of the first boom 11, and the distal end of the cylinder tube 15 b is attached to the proximal end of the second boom 12. A counterbalance valve 18 is attached to the top of the piston rod 15a of the hydraulic cylinder 15 inside the base end of the first boom 11, and the hydraulic oil supplied to the counterbalance valve 18 is provided to smoothly extend and retract the hydraulic cylinder 15. Is controlled. Also, the second boom 12
The third boom reduction sheave 23 around which the wire 21 attached between the distal end of the first boom 11 and the proximal end of the third boom 13 is mounted on the mounting shaft 15c of the cylinder tube 15b. I have. further,
At the base end of the third boom 13, a projecting portion 13 a in the base direction is formed, and at the base end of the projecting portion 13 a, the tip of the second boom 12 and the fourth boom 14 are provided.
A fourth boom reducing sheave 24 around which a wire 22 attached around the base end is wound is attached. The third boom reduction sheave 23 and the fourth boom reduction sheave 24 are provided as a pair, respectively.
Both the third boom reduction sheaves 23 are arranged on the mounting shaft 15 c so as to be located inside the third boom 13 when the second boom 12 is reduced with respect to the second boom 12.

In the multi-stage telescopic boom 10 provided with the reduction wire mechanism configured as described above, when the second boom 12 is reduced with respect to the first boom 11 by the reduction operation of the hydraulic cylinder 15, the second boom 12 is moved together with the second boom 12. The third boom 13 is pulled toward the first boom 11 to be reduced while the third boom reduction sheave 23 moves in the proximal direction.
Similarly, when the third boom 13 is reduced with respect to the second boom 12, the fourth boom 14 is moved with respect to the third boom 13 while the third boom 13 and the fourth boom reduction sheave 24 move in the proximal direction. To pull down. In this manner, the entire multi-stage telescopic boom 10 is reduced.

By the way, in this multistage telescopic boom 10,
When the third boom 13 is reduced with respect to the second boom 12, as shown in the figure, the projecting portion 13a of the third boom 13 to which the fourth boom reduction sheave 24 is attached is located above the third boom reduction sheave 23. Is located proximally beyond. Therefore, above the counterbalance valve 18 inside the base end of the first boom 11,
a and a storage space 11a for accommodating the fourth boom reduction sheave 24 is formed. The storage space 11
A hydraulic hose 18a for supplying and discharging hydraulic oil to and from the counter balance valve 18 is connected to the side surface of the counter balance valve 18 in order to obtain a sufficient value of a. By forming the storage space 11a in this way, even when the hydraulic cylinder 15 is fully contracted and the second boom 12 is fully contracted with respect to the first boom 11, the overhang portion 13a and the fourth boom contraction The sheave 24 is provided in the storage space 11 without interfering with the counterbalance valve 18.
a. Therefore, the third boom 13 is moved to the second
The boom 12 can be sufficiently reduced. Furthermore, by positioning the fourth boom reduction sheave 24 in the proximal direction, the fourth boom 14 can be sufficiently reduced with respect to the third boom 13 without fear of interference with the fourth boom reduction sheave 24. Can be. As explained above,
In the multi-stage telescopic boom 10, the boom length in the fully contracted state can be made sufficiently shorter than the length in the fully extended state. Therefore, as shown in FIG. 1, the multistage telescopic boom 10 can be stored within the range of the cabback 2 of the truck.

Although not shown, the multi-stage telescopic boom 10 is provided with a similarly configured extending wire mechanism. In the above embodiment, the multi-stage telescopic boom is a four-stage type. However, the present invention can be applied to a multi-stage telescopic boom having five or more stages. Further, in the above-described embodiment, the multi-stage telescopic boom used for the crane truck has been described.
The cross-boom telescopic boom according to the present invention is not limited to this, and can be employed, for example, in an aerial work vehicle having a multi-stage telescopic boom with a work table attached to the tip thereof.

[0013]

As described above, in the multistage telescopic boom according to the present invention, a storage space for storing the fourth boom reduction sheave attached to the base end of the third boom is formed inside the base end of the first boom. Have been. For this reason, the third boom is sufficiently reduced with respect to the second boom, that is, in a state where the fourth boom reduction sheave is reduced to a position near the base end beyond the attachment position of the third boom reduction sheave. , Move the second boom to the first
Fully shrinkable for the boom. Therefore, the length of the multi-stage telescopic boom in the fully contracted state can be made sufficiently shorter than the length in the fully extended state, and the truck can be easily mounted on a cab back or the like.

[Brief description of the drawings]

FIG. 1 is a side view of a crane equipped with a multi-stage telescopic boom according to the present invention.

FIG. 2A is a side sectional view of the multistage telescopic boom,
(B) is a sectional view taken along line II-II in (A).

FIG. 3A is a side sectional view of a conventional multistage telescopic boom, and FIG. 3B is a sectional view taken along line VV in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Multistage telescopic boom 11 1st boom 12 2nd boom 13 3rd boom 14 4th boom 15 Hydraulic cylinder 18 Counter balance valve (hydraulic oil control device) 21,22 Wire 23 3rd boom reduction sheave 24 4th boom reduction Sheave 11a storage space

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-177889 (JP, A) JP-A-64-81797 (JP, A) JP-A-50-58751 (JP, A) 126395 (JP, U) Actually open 1986-119586 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A first boom attached to a base, a second boom inserted into the first boom so as to be extendable and contractable toward a distal end thereof, and a second boom is inserted into the second boom toward a distal end thereof. And a fourth boom telescopically inserted into the third boom and a fourth boom telescopically inserted into the third boom toward the distal end thereof. And between the second boom, the second
A hydraulic cylinder for extending and retracting the boom with respect to the first boom is mounted, and a hydraulic oil control device for controlling hydraulic oil supplied to the hydraulic cylinder is mounted inside a base end of the first boom. A third boom reduction sheave around which a wire attached between the distal end of the first boom and the proximal end of the third boom is wound on the proximal end of the second boom. A fourth boom reduction sheave, which is attached to a proximal end of the third boom and wound around a wire attached between a distal end of the second boom and a proximal end of the fourth boom. And a storage space in which the fourth boom reduction sheave is accommodated above or below the hydraulic oil control device inside the base end of the first boom. When the multi-stage telescopic boom is fully reduced, the fourth boom reduction sheave is located closer to the proximal end than the third boom reduction sheave and is stored in the storage space. Characteristic multi-stage telescopic boom.