JPH11106181A - Simultaneous expansion/contraction mechanism of expandable boom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the tension regulating work, and to miniaturize the structure of a tension regulating means. SOLUTION: A tension regulating means 30 comprises a first regulation bolt 36 which is composed of a bolt member, and moves the other end 23b of an expansion side wire rope 23 in the axial direction of an expandable boom by its screwing operation, and a second regulation bolt 37 which moves the other end 24b of a contraction side wire rope in the axial direction of the expandable boom by the screwing operation of a hollow bolt member provided with a through hole 37d and in which the first regulation bolt is coaxially inserted in the through hole 37d. The tension of the wire rope on the expansion side and on the contraction side is regulated by the screwing operation of each regulation bolt by the tension regulating means. Because the first regulation bolt and the second regulation bolt are of the double bolt structure, the tension regulating means is miniaturized, its occupied space is reduced, and the layout of the expandable boom can be easily designed. The workability of each regulation bolt is improved by continuously achieving the screwing operation at the same working position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous extension / retraction mechanism of a telescopic boom, and more particularly to a structure of a tension adjusting mechanism of a telescopic wire rope in the simultaneous extension / retraction mechanism.

[0002]

2. Description of the Related Art Conventionally, in the case of a telescopic boom, a plurality of booms have to be simultaneously extended and retracted in a synchronized manner.
Some have a simultaneous expansion and contraction mechanism. As this simultaneous expansion / contraction mechanism, for example, as disclosed in Japanese Utility Model Laid-Open No. 4-44282, a mechanism configured by combining an expansion / contraction cylinder and an expansion / contraction wire rope is known.

That is, the simultaneous expansion and contraction mechanism of the telescopic boom, which is a combination of the telescopic cylinder and the telescopic wire rope, includes at least three telescopically mounted booms, ie, a base end boom and the base end boom. The present invention is directed to a telescopic boom including an intermediate boom telescopically inserted into a side boom and a distal end boom telescopically inserted into the intermediate boom. The distal end of the piston rod is provided at the base end of the end boom, and the rod end of the cylinder tube is provided at the base end of the intermediate boom. Of the extension side sheave provided at the bottom end of the boom is U-shaped, and one end is provided at the base end of the distal boom and the other end is provided at the base boom. The extension-side wire rope fixed to the connecting member, and a U-shaped loop around the compression-side sheave provided at the rod-side end of the telescopic cylinder, and one end of which is connected to the base end of the distal-side boom. And a compression-side wire rope having the other end fixed to the connection member.

When the telescopic boom is extended from a contracted state, the telescopic cylinder is extended to extend the intermediate boom with respect to the base end boom, and at the same time, the extension displacement of the intermediate boom is extended. The distal boom is transmitted to the distal boom via the side wire rope to extend the distal boom with respect to the intermediate boom. Further, at the time of the retracting operation of the telescopic boom from the extended state, the telescopic cylinder is contracted to contract the intermediate boom with respect to the base end boom, and at the same time, the contraction displacement of the intermediate boom is controlled by the contracting wire rope. And transmitted to the distal end boom through the central boom.

On the other hand, in a telescopic boom provided with such a simultaneous telescopic mechanism using the extension side wire rope and the contraction side wire rope, if the tension of each of the wire ropes is not appropriate, the connection is made via each of the wire ropes. Rattling occurs between the intermediate boom and the distal end boom. For this reason, of course, the tension of each wire rope is adjusted at the time of shipment from the factory, and even after shipment, the above-mentioned each wire rope exerts its own weight during the extension / retraction operation of the extension / extension boom and the tension caused by the hanging load suspended at the tip of the extension / extension boom. Since the wire rope gradually expands during long-term use, the tension of each of the wire ropes is periodically adjusted.

[0006]

In the conventional telescopic boom simultaneous expansion and contraction mechanism, as disclosed in the above-mentioned known example, the expansion side tension adjusting means for adjusting the tension of the expansion side wire rope is provided. The compression side tension adjusting means for adjusting the tension of the compression side wire rope is disposed at the distal end of the connecting member which is positioned at the distal end side of the telescopic boom when the telescopic boom is in the most contracted state. The tension adjusting means on the extension side and the tension adjusting means on the compression side are arranged at appropriate distances from each other, so that the operation of each tension adjusting means can be performed in a sufficient working space.

However, the size of the internal space of the telescopic boom is restricted by the necessity of reducing the weight of the boom, and cannot be enlarged without permission. For this reason, if the tension adjusting means are separately arranged in the restricted space while securing a required working space, the occupancy of the tension adjusting means in the space increases, and as a result, In addition, the arrangement space of other members (for example, sheaves) arranged together with the respective tension adjusting means in the space is narrowed, and the layout design of various components arranged inside the telescopic boom may be hindered. Become.

In view of the above, the present invention provides a simultaneous extension and contraction mechanism of the telescopic boom, which aims at achieving both the easiness of the operation of adjusting the tension of the wire rope by the tension adjusting means and the downsizing of the structure of the tension adjusting means. It is.

[0009]

According to the present invention, the following configuration is employed as specific means for solving the above-mentioned problems.

That is, the proximal boom 4 and the proximal boom 4
Boom 5 that is telescopically inserted into the middle boom 5
The distal end of a piston rod 9B is connected to the proximal end 4a of the proximal end boom 4 of the telescopic boom 1 having a distal end boom 6 which is inserted and retractably inserted into the base boom 6. With the piston rod end of the cylinder tube 9A connected to the end 5a, the telescopic boom 1
A telescopic cylinder 9 internally provided therein, an extending sheave 21 disposed at a bottom end of the cylinder tube 9A in the telescopic cylinder 9, and a piston rod of the cylinder tube 9A in the telescopic cylinder 9. Contraction side sheave 22 arranged at the side end, and its base end 2
A connecting member 29 internally provided in the telescopic boom 1 in the axial direction of the telescopic boom 1 with the base 9a connected to the base end 4a of the base end boom 4;
And an extension wire rope 23 whose one end 23a is fixed to the base end 6a of the distal end boom 6 and the other end 23b is fixed to the distal end 29b of the connecting member 29. It is wrapped around the compression side sheave 22 in a U-shape, one end 24a of which is at the base end 6a of the distal end boom 6 and the other end 24b thereof is at the connection member 29
And a retractable wire rope 24 fixed to the distal end portion 29b of the intermediate boom 5 with respect to the base end boom 4 by the telescopic operation of the telescopic cylinder 9. The telescopic displacement is transmitted to the distal end boom 6 via the extension side wire rope 23 or the contraction side wire rope 24 to extend and retract the distal end boom 6 with respect to the intermediate boom 5. In the telescopic mechanism, the distal end portion 29b of the connecting member 29
The extension side wire rope 23 and the contraction side wire rope 24
A tension adjusting means 30 for adjusting the tension is attached, and the tension adjusting means 30 is formed of a bolt member, and the other end 23b of the extension wire rope 23 or the compression side wire rope 24 is The other end 24
b is constituted by a first adjustment bolt 36 configured to be able to move the b in the axial direction of the telescopic boom 1 and a hollow bolt member having a through hole 37d penetrating through the axial center portion, and the above operation is performed by a screwing operation. The other end 24 of the compression side wire rope 24
b or the other end 23b of the extension side wire rope 23 is configured to be movable in the axial direction of the telescopic boom 1 and the first adjustment bolt 36 is provided in the through hole 37d.
And a second adjustment bolt 37 fitted and arranged substantially coaxially, and the tension of the extension side wire rope 23 or the contraction side wire rope 24 is adjusted by screwing the first adjustment bolt 36, By the screwing operation of the second adjusting bolt 37, the contraction side wire rope 24 or the extension side wire rope 2
3 is configured to perform the tension adjustment.

[0011]

According to the present invention, the following effects can be obtained by adopting such a configuration. That is, according to the simultaneous telescopic boom telescopic mechanism of the present invention, when the telescopic boom 1 is in a contracted state, the distal end 29b of the connecting member 29 located on the distal end side of the telescopic boom 1 is formed of a bolt member and The other end 2 of the extension side wire rope 23 is turned by the screwing operation.
3b or a first adjusting bolt 36 configured to move the other end 24b of the contraction side wire rope 24 in the axial direction of the telescopic boom 1 and a bolt member. The other end 24 of the rope 24
b or the second adjusting bolt 37 configured to move the other end 23b of the extension-side wire rope 23 in the axial direction of the telescopic boom 1, so that the tension adjusting means 30 is attached. The first adjusting bolt 36 is appropriately screwed to rotate the other end 23 of the extension side wire rope 23.
b or the other end 24b of the contraction side wire rope 24 is moved in the axial direction of the telescopic boom 1 to adjust the tension of the extension side wire rope 23 or the contraction side wire rope 24, and the second adjustment The other end 24b of the contraction-side wire rope 24 or the other end 23b of the extension-side wire rope 23 is moved in the axial direction of the telescopic boom 1 by appropriately screwing the bolt 37, whereby the contraction-side wire rope 24 or The tension of the extension wire rope 23 is adjusted.

In this case, of the first adjusting bolt 36 and the second adjusting bolt 37 constituting the tension adjusting means 30, the second adjusting bolt 37 is inserted into the through hole 37 at the axis thereof.
d, and the first adjusting bolt 36 is substantially coaxially inserted and disposed in the through hole 37d of the second adjusting bolt 37, thereby forming the first adjusting bolt 36.
And the second adjusting bolt 37 have a double bolt structure, and the first adjusting bolt 36 and the second adjusting bolt 37 can be individually operated in the double bolt structure. First adjustment bolt 36
The first adjustment bolt 36 and the second adjustment bolt 37 overlap with each other as compared with the case where the first adjustment bolt 36 and the second adjustment bolt 37 are separated from each other as a completely separate structure as in the related art. However, the form of the tension adjusting means 30 as a whole becomes compact, and the space occupied by the tension adjusting means 30 in the internal space of the telescopic boom 1 can be reduced. As a result, as the space occupied by the tension adjusting means 30 inside the telescopic boom 1 decreases, the arrangement space for other members arranged inside the telescopic boom 1 together with the tension adjusting means 30 increases, The degree of freedom of the layout of these members is increased, and the structural design of the entirety of the telescopic boom 1 is facilitated, and the production cost of the telescopic boom 1 is further reduced.

Further, since the first adjusting bolt 36 and the second adjusting bolt 37 have a double bolt structure, the first adjusting bolt 36 and the second adjusting bolt 37 are respectively screwed to operate. When adjusting the tension of each of the wire ropes 23 and 24, the operator can continuously perform the screwing operation of the bolts 36 and 37 at the same working position. Compared with the case where it is necessary to perform the turning operation at separate working positions, the tension adjusting operation becomes simpler and faster, and the workability can be greatly improved.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a simultaneous extension / retraction mechanism of a telescopic boom according to the present invention.

First Embodiment FIG. 1 shows a five-stage telescopic boom 1 for a truck crane provided with a simultaneous telescopic mechanism 20, which will be described later, according to a first embodiment of the present invention. Reference numeral 2 denotes a first-stage boom located at the most proximal end side, 3 denotes a second-stage boom that is inserted and arranged to be able to expand and contract with the first-stage boom 2, and 4 denotes a second-stage boom that can be extended and contracted by the second-stage boom The third-stage boom 5 is inserted and arranged in the third stage boom 4 and the fourth-stage boom is inserted and arranged in the third stage boom 4 so as to be able to expand and contract. This is the fifth stage boom inserted and arranged.

The simultaneous expansion and contraction mechanism 20 includes three booms on the distal end side, ie, the third to fourth booms 6 to 6.
Between the third stage boom 4 and the fourth stage boom 5 and the fifth stage boom 6 at the same time. Therefore, in this embodiment, the third stage boom 5 The boom 4 is the “proximal boom” in the claims.
The fourth-stage boom 5 corresponds to an “intermediate boom” in the claims, and the fifth-stage boom 6 corresponds to a “tip-side boom” in the claims. Further, the fifth stage boom 6 is provided with a working opening 28 on the front wall of the distal end portion 6b for performing the operation of the tension adjusting means 30 described later from outside the boom distal end side.

The simultaneous expansion and contraction mechanism 20 includes three cylinders described below, that is, the first expansion and contraction cylinder 7, the second expansion and contraction cylinder 8, and the third expansion and contraction cylinder 9 out of the third expansion and contraction cylinder 9. And two wire ropes, that is, an extension wire rope 23 and a contraction wire rope 24.

The first telescopic cylinder 7 drives the second-stage boom 3 to extend and retract with respect to the first-stage boom 2, and the distal end of a piston rod 7 B is pivoted by a pivot shaft 12 to the first-stage boom 2. With the base end 2a of the eye boom 2 pivotally supported, and the piston rod side end of the cylinder tube 7A pivotally supported by the base end 3a of the second stage boom 3 by the pivot shaft 13, The telescopic boom 1 is fitted inside the telescopic boom 1 so as to be substantially parallel to the axial direction. A support roller 16 for supporting the bottom end of the cylinder tube 7A of the first telescopic cylinder 7 is provided at the bottom end.

The second telescopic cylinder 8 is for driving the third-stage boom 4 to extend and retract with respect to the second-stage boom 3, and pivots the end of the cylinder tube 8 A on the piston rod side. The third stage boom 4 is supported by the support shaft 14.
And the distal end of the piston rod 8B, together with the cylinder tube 7A of the first telescopic cylinder 7, is connected to the proximal end 3a of the second stage boom 3 by the pivot shaft 13. In the state of being pivotally supported on the telescopic boom 1, it is fitted and arranged so as to be positioned inside the telescopic boom 1 and above the first telescopic cylinder 7. In addition, a connecting rod 10 of a predetermined length, which extends rearward in the axial direction from the end of the cylinder tube 8A and has a supporting roller 17, is integrally formed at the bottom end of the cylinder tube 8A in the second telescopic cylinder 8. Attached to. The second telescopic cylinder 8 constitutes a “connecting member 29” in an integrated state with the connecting rod 10 in the claims.

The third telescopic cylinder 9 drives the fourth telescopic boom 5 to extend and retract with respect to the third telescopic boom 4, and the distal end of the piston rod 9B is connected to the second telescopic cylinder. 8 together with the cylinder tube 8A, is pivotally supported by the pivot shaft 14 on the base end 4a of the third stage boom 4, while the piston rod side end of the cylinder tube 9A is pivotally supported by the pivot shaft 15 in the fourth stage boom. The boom 5 is pivotally supported at a base end 5 a. A connecting rod 11 having a predetermined length extending rearward from the end is integrally fixed to the bottom end of the cylinder tube 9A. A pair of extension sheaves 21 and 21 are rotatably attached by a sheave shaft 27. Further, a pair of contraction-side sheaves 22, 22 disposed on the right and left sides of the end of the cylinder tube 9 </ b> A, respectively, are rotatably mounted on the piston rod side by the pivot shaft 15. The connecting rod 1
A support roller 18 and a support roller 19 are arranged at the tip of the device 1.

On the other hand, as shown in FIG. 1, a fixing portion 25A for fixing a cable end of the wire rope and a U-shaped wire rope are provided on the inner surface of the top plate at the base end 6a of the fifth stage boom 6. A cable end fixing member 25 provided with a folded sheave 25B for folding back is mounted. Further, as shown in FIGS. 1 to 3, at the distal end of the connecting rod 10, a folded sheave 26 described later for folding the wire rope, and a first movable body described later for fixing the cable end of the wire rope. The bases 33 are arranged respectively. Then, the extension side wire rope 23 and the compression side wire rope 24 are folded back in two, respectively, and the extension side sheave 21,
The proximal end 6a of the fifth-stage boom 6 and the distal end of the connecting rod 10, ie, the connecting member 2
9 and the front end portion 29b.

That is, the extension side wire rope 23 is configured such that both cut ends 23a, 23a (corresponding to “one end 23a” in the claims) of the folded wire rope are respectively connected to the cable end fixing member 25. While being fixed to the fixing portion 25A, this is pulled out from the cable end fixing member 25 toward the boom tip side, and is wrapped around the pair of left and right extending sheaves 21 and 21 from above to below in a U-shape, respectively. By winding the folded portion 23b (corresponding to the “other end 23b” in the claims) around the folded sheave 26, the base end 6a of the fifth boom 6 and the distal end 29b of the connecting member 29 are formed. It is stretched between.

The shrinking-side wire rope 24 has a folded portion 24a ("one end 24a" in the claims).
The sheave 2 of the cable end fixing member 25 described above.
5B, is pulled out to the boom base end side and wound around the pair of contraction side sheaves 22 from the upper side to the lower side, and further from the contraction side sheaves 22, 22 toward the boom tip side. And both cut ends 24b, 2
4b (corresponding to "the other end 24b" in the claims)
Is fixed to the first movable base 33 via cable end fixing bolts 34, 34 (see FIG. 3) attached thereto, so that the base end portion 6a of the fifth stage boom 6 and the connecting member are fixed. 2
9 and the front end portion 29b.

The above-described simultaneous expansion and contraction mechanism 2 having the above configuration
By providing 0, the simultaneous expansion and contraction operation of the expansion and contraction boom 1 is realized as described below.

For example, as shown in FIG. 1, in order to extend the telescopic boom 1 in the minimum contracted position from the minimum contracted position, first extend the telescopic cylinders 7 to 9 simultaneously or sequentially. Activate. Then, the first stage boom 2 is extended by the extension operation of the first telescopic cylinder 7.
The second-stage boom 3 is extended, and the second-stage boom 3 is extended by the extension operation of the second telescopic cylinder 8.
The third stage boom 4 extends, and
The fourth stage boom 5 is extended with respect to the third stage boom 4 by the extension operation of the telescopic cylinder 9. Further, in this case, since the fourth-stage boom 5 and the fifth-stage boom 6 are connected via the extension-side wire rope 23 and the connection member 29, the extension operation of the third telescopic cylinder 9 causes When the fourth-stage boom 5 is extended with respect to the third-stage boom 4, the third-stage boom 4 and the fourth-stage boom 5 are extended.
Is transmitted to the fifth-stage boom 6 via the tension of the extension-side wire rope 23, and the fifth-stage boom 6 extends at twice the extension speed of the fourth-stage boom 5. I do. As a result, the extension of the telescopic boom 1 is realized.

Conversely, when the telescopic boom 1 in the extended state is contracted, first, the telescopic cylinders 7 to 9 are contracted simultaneously or sequentially. Then
The second stage boom 3 is contracted with respect to the first stage boom 2 by the contraction operation of the first telescopic cylinder 7, and the second stage boom 3 is contracted by the contraction operation of the second telescopic cylinder 8. The third stage boom 4 is contracted, and the fourth stage boom 5 is contracted with respect to the third stage boom 4 by the contraction operation of the third telescopic cylinder 9.
Further, in this case, the fourth-stage boom 5 and the fifth-stage boom 6 are connected to the contraction-side wire rope 24 and the connecting member 29.
When the fourth stage boom 5 is contracted with respect to the third stage boom 4 by the contraction operation of the third telescopic cylinder 9, the third stage boom 4 and the fourth stage boom are connected. 5 changes in the relative position of the wire rope 2
The fifth stage boom 6 is transmitted to the fifth stage boom 6 via the tension of 4, and the fifth stage boom 6 is reduced at twice the reduction speed of the fourth stage boom 5. As a result, the contraction boom 1 is reduced.

By the way, the simultaneous expansion and contraction of the fourth boom 5 and the fifth boom 6 performed through the extension wire rope 23 or the contraction wire rope 24 must be performed smoothly and without looseness. The tension of the extension-side wire rope 23 and the contraction-side wire rope 24 is adjusted to an appropriate state.
It is necessary that 3, 3 have no excessive slack.

Even if the tension of the wire ropes 23 and 24 is adjusted, if the means for adjusting the tension is arranged with a large occupied space inside the distal end of the telescopic boom 1, It is not preferable because it hinders the degree of freedom of installation of other members arranged inside, for example, the extension sheave 21 and the like. Further, when the work position of each of the wire ropes 23 and 24 needs to be changed when performing the work of adjusting the tension of the wire ropes 23 and 24 by the tension adjusting means, it is not preferable in terms of simplifying and speeding up the work.

In consideration of such circumstances, in this embodiment, the present invention is applied to the configuration of the tension adjusting means 30 described below to reduce the size of the tension adjusting means 30 and simplify and speed up the tension adjusting operation. I'm trying. Hereinafter, the specific configuration and operation of the tension adjusting means 30 will be described in detail with reference to FIGS.

The tension adjusting means 30 adjusts the tension of the extension-side wire rope 23 by moving the folded sheave 26 around which the other end 23b of the extension-side wire rope 23 is hung around in the boom axis direction. The first end to which the other ends 24b, 24b of the compression side wire rope 24 are fixed.
The tension of the contraction side wire rope 24 is adjusted by moving the movable base 33 in the boom axis direction. The first adjustment bolt 36 and the second adjustment bolt 37 described below are provided. First and second adjusting bolts 36 and 37, which will be described later, are provided to exert their original functions.
Fixed bases 31, 32, a first movable base 33, and a second movable base 38 are provided.

The first adjusting bolt 36 is formed of a bolt having a predetermined length, and has an outer thread engraved on the outer peripheral surface of the shaft portion 36b.

The second adjusting bolt 37 is constituted by a hollow bolt body having a through hole 37d at its axial center portion into which the first adjusting bolt 36 can be loosely fitted. Screws are engraved. The axial length of the second adjusting bolt 37 is set to a dimension shorter than the axial length of the shaft portion 36b of the first adjusting bolt 36 by a predetermined dimension. When the bolt 37 is inserted into the through hole 37d, the tip surface 36c of the first adjustment bolt 36 projects forward by a predetermined distance from the tip surface 37c of the second adjustment bolt 37.

The first fixing base 31 is a rectangular body having a through hole 31a into which the second adjusting bolt 37 can be loosely fitted, and is fixed to the connecting rod 10. The first fixed base 31 is provided in the through hole 31a with the second fixed base 31.
When the adjusting bolt 37 is fitted, the front surface 31
When the head 37a of the second adjusting bolt 37 is abutted against b, the second adjusting bolt 37 acts to restrict the movement of the second adjusting bolt 37 toward the boom base end.

The second fixing base 32 is formed of a rectangular body having a screw hole 32b into which the shaft 36b of the first adjusting bolt 36 is screwed. The second fixed base 32 is connected to the first fixed base 31 of the connecting rod 10.
At the rear side (near the boom base end) of the first fixed base 3
1 and the screw hole 32b is inserted into the first
It is fixed in a state where it is positioned substantially coaxially with the through hole 31 a of the fixed base 31. The second fixing base 32 screw-holds the first adjustment bolt 36 and holds the first adjustment bolt 3.
6, and also functions as a regulating member that regulates the maximum movement amount of the first movable base 33 to the boom base end side described below.

The first movable base 33 has a rectangular main body portion 33A having a screw hole 35 into which the shaft portion 37b of the second adjusting bolt 37 is screwed, and is provided on both left and right sides of the main body portion 33A. The main body 33A is fixed to the main body portion 33A in an extended state, and the main body portion 33A is integrated with the extension portions 33B and 33B. This first
The movable base 33 is disposed at an intermediate position between the first fixed base 31 and the second fixed base 32 and is movable in the boom axis direction. The screw hole 35 of the first movable base 33 has a through hole 31 a of the first fixed base 31.
Shaft portion 3 of the second adjustment bolt 37 disposed through
7b is screwed into each of the extended portions 33B, 33B, and a pair of left and right other ends 24
A pair of right and left rope end stop bolts 34, 34 fixed to each of b, 24b are fixed by nuts 41, 41. Accordingly, the tension of the contraction-side wire rope 24 is adjusted (that is, the rope length is adjusted) by moving the first movable base 33 in the front-rear direction (boom axis direction).

The second movable base 38 is connected to the connecting rod 10.
At the rear side (the base end side of the boom) of the second fixed base 32, and is configured to be movable in the boom axis direction. The folded sheave 26 around which the other end 23b of the extension-side wire rope 23 is wound is integrally fixed to the second movable base 38. The front surface 38a of the second movable base 38 has the second
The second fixing base 3 is screwed into the screw hole 32b of the second fixing base 32 through a through hole 37d of the adjusting bolt 37.
The distal end surface 36c of the first adjusting bolt 36 protruding to the rear surface side of the second abutment 2 comes into contact with the second adjustable base 38 so that the movement of the second movable base 38 toward the boom distal end side is restricted by the contact with the distal end surface 36c. It has become. Therefore, the first adjusting bolt 36
Is screwed to advance and retreat with respect to the second fixed base 32, so that the second movable base 38 and the folded sheave 26 are pressed by the first adjustment bolt 36 with the extension force. In response to the tension of the side wire rope 23, it is moved in the direction of the boom axis, whereby the tension of the extension side wire rope 23 is adjusted.

In FIG. 2, reference numeral 40 designates a detent member sandwiched between a pair of front and rear nuts 42, 42 screwed to the shaft portion 36b of the first adjusting bolt 36. One end 40a is connected to the second adjustment bolt 3
The second adjusting bolt 37 and the first adjusting bolt 36 are prevented from rotating by abuttingly engaging with the head 37a of the seventh adjusting bolt 37.

According to the tension adjusting means 30 configured as described above, the operator inserts his hand through the working opening 28 provided on the distal end face of the fifth stage boom 6 to form a double bolt structure. First adjusting bolt 36 and second adjusting bolt 37
Are individually screwed to adjust the tension (normally, the tension recovery operation) of the extension-side wire rope 23 and the compression-side wire rope 24, respectively. Can be easily and quickly performed under the same working position and working posture.

That is, first, the nuts 42, 42 are loosened to remove the detent member 40, and then the first adjustment bolt 36 is appropriately tightened.
The second movable base 38 is pushed and moved to the base end side of the boom together with the folded sheave 26 by the distal end surface 36c. The tension of the extension wire rope 23 is adjusted by the movement of the folded sheave 26 toward the base end of the boom.
At this time, since the first adjustment bolt 36 is loosely fitted into the through hole 37d of the second adjustment bolt 37,
Regardless of the operation of the adjustment bolt 36, the second adjustment bolt 3
In the state 7, the non-operation state is maintained.

Next, the second adjusting bolt 37 is screwed in the tightening direction. Then, the second adjustment bolt 37
Since the movement to the boom base end side is regulated by the first fixed base 31, the first movable base 33 moves to the boom tip side by tightening the second adjustment bolt 37, and The tension of the contraction-side wire rope 24 having the other ends 24b, 24b fixed to the first movable base 33 is adjusted. In this case, the screwing operation of the second adjustment bolt 37 does not affect the first adjustment bolt 36 at all.

When the tension adjustment of the extension side wire rope 23 and the contraction side wire rope 24 is completed by operating the first adjustment bolt 36 and the second adjustment bolt 37, respectively, the detent member 40 is attached and these bolts are attached. 36, 37
Regulate the rotation of This completes the tension adjustment work.

As described above, in the tension adjusting means 30 of this embodiment, the first adjusting bolt 3 constituting the tension adjusting means 30 is used.
6 and the second adjusting bolt 37 have a double bolt structure, so that, for example, the first adjusting bolt 36 and the second adjusting bolt 37 have a completely separate structure as in the prior art, and are separated from each other. Compared to the case of a structure installed
Since the first adjusting bolt 36 and the second adjusting bolt 37 overlap, the form of the tension adjusting means 30 as a whole becomes more compact. As a result, the space occupied by the tension adjusting means 30 in the internal space of the telescopic boom 1 is reduced, and as a reflexive effect, other members (for example, disposed inside the telescopic boom 1 together with the tension adjusting means 30) , The extension side sheave 21, etc.), the degree of freedom in the layout design of the component members is increased accordingly, and the telescopic boom 1 is extended.
In this way, the manufacturing cost can be reduced.

On the other hand, the first adjustment bolt 36 and the second
Since the adjusting bolt 37 and the adjusting bolt 37 have a double bolt structure, when the first adjusting bolt 36 and the second adjusting bolt 37 are each screw-operated to adjust the tension of the wire ropes 23 and 24, a work is required. The two bolts 36, 37
Can be continuously performed at the same work position. For example, the tension adjustment work can be performed as compared with the case where the screw operations of both bolts 36 and 37 need to be performed from separate work positions. Becomes even easier and faster,
The workability can be improved.

Second Embodiment FIG. 4 shows a portion of a simultaneous extension and contraction mechanism 20 according to a second embodiment of the present invention, which is closer to the distal end of an extension boom (corresponding to FIG. 2 in the first embodiment). ). The simultaneous expansion and contraction mechanism 20 of this embodiment is different from the simultaneous expansion and contraction mechanism 20 of the first embodiment in that the other end 23b of the extension side wire rope 23 is moved in the boom axial direction by screwing the first adjustment bolt 36. Move to the contraction side wire rope 24
The other end 24b of the compression side wire rope 24 is moved in the boom axis direction by screwing the second adjustment bolt 37.
4b is moved in the boom axis direction by the screwing operation of the first adjustment bolt 36, and the other end 23b of the extension wire rope 23 is moved in the boom axis direction by the screwing operation of the second adjustment bolt 37. It is composed.

That is, as shown in FIG. 4, the second adjusting bolt 37 having a hollow shaft shape is rotatably supported by a pair of front and rear fixing bases 54 and 55 fixed to the connecting rod 10, and the shaft thereof is rotatable. A movable base 51 having a screw hole 51a is screwed into the portion 37b, and a folded sheave 26 around which the other end 23b of the extension side wire rope 23 is hung is fixed to the movable base 51. Using the fact that the movable base 51 is moved in the axial direction of the second adjustment bolt 37 by the screwing operation of the second adjustment bolt 37, the extension wire rope 23 is used.
The tension is adjusted. In this case, the tension of the extension-side wire rope 23 is supported by the stopper 53 fixed to the distal end portion of the shaft portion 37b of the second adjustment bolt 37 abutting on the fixing base 55.

On the other hand, the first adjusting bolt 36 is disposed so as to pass through the through hole 37d of the second adjusting bolt 37, and the tip thereof is rotated by a fixed base 56 fixed to the connecting rod 10. It is freely supported. The shaft portion 36b of the first adjusting bolt 36 has a screw hole 52a.
The movable base 52 provided with is screwed. Further, to the movable base 52, a folded sheave 45 around which the other end 24b on the folded side of the compression-side wire rope 24 is looped is fixed. Therefore, when the first adjustment bolt 36 is screwed, the movable base 52 is moved to the first adjustment bolt 3.
6 to adjust the tension of the contraction-side wire rope 24. In this case, the tension of the compression side wire rope 24 is adjusted by the first adjusting bolt 3.
6 is a head 37a of the second adjusting bolt 37.
Is supported by contact with

It should be noted that the simultaneous expansion and contraction mechanism 20 according to the second embodiment can provide the same operation and effect as the simultaneous expansion and contraction mechanism 20 according to the first embodiment.

In addition, the present invention is not limited by the extending structure of the extension side wire rope 23 and the contraction side wire rope 24, and each of the wire ropes 23, 24 has a cut end or a folded end. Even if the telescopic boom 1 is arranged near the distal end, the intended purpose can be achieved without any trouble.
For example, in the first embodiment, the folded sheave 25A in which one end 24a, which is the folded end of the contraction side wire rope 24, is provided at the base end of the fifth stage boom 6 is provided.
In the second embodiment, the other end 24b, which is the folded end of the contraction-side wire rope 24, is wound around the folded sheave 45 provided near the extension-side sheave 21 in the second embodiment. It is like.

[Brief description of the drawings]

FIG. 1 is a side view showing a drive structure of a telescopic boom provided with a simultaneous telescopic mechanism according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a distal end portion of the telescopic boom shown in FIG.

FIG. 3 is an exploded perspective view of the wire adjusting means shown in FIG.

FIG. 4 is a side view of a distal end portion of a telescopic boom provided with a simultaneous telescopic mechanism according to a second embodiment of the present invention.

[Explanation of symbols]

1 is a telescopic boom, 2 is a first-stage boom, 3 is a second-stage boom, 4 is a third-stage boom, 5 is a fourth-stage boom, 6 is a fifth-stage boom, 7 to 9 are telescopic Linders, 10 and 11 Is a connecting rod, 12 to 15 are pivot shafts, 16 to 19 are support rollers, 2
Numeral 0 is a simultaneous expansion and contraction mechanism, 21 is a stretching sheave, 22 is a shrinking sheave, 23 is a stretching wire rope, 24 is a shrinking wire rope, 25 is a cable end fixing member, 26 is a folded sheave, 27 is a sheave shaft, 28 Is a working opening, 29 is a connecting member, 30 is a tension adjusting means, 31 is a first fixed base, 32 is a second fixed base, 33 is a first movable base, 34 is a cable end stop bolt, and 35 is a screw. The hole, 36 is the first adjustment bolt, 37 is the second adjustment bolt, 38 is the second movable base, 40 is the detent member, 41 to 41
42 is a nut, 45 is a folded sheave, 51 and 52 are movable bases, 53 is a stopper, and 54 to 56 are fixed bases.

Claims (1)

[Claims] 1. A base boom (4), an intermediate boom (5) telescopically inserted into the base boom (4), and a distal end telescopically inserted into the intermediate boom (5). A piston rod (9) is provided on the base end (4a) of the base end boom (4) of the telescopic boom (1) including the side boom (6).
B) and the piston rod side end of the cylinder tube (9A) is connected to the base end (5a) of the intermediate boom (5) and the inside of the telescopic boom (1). The telescopic cylinder (9), and the extension-side sheave (2) disposed at the bottom end of the cylinder tube (9A) in the telescopic cylinder (9).
1), a contraction-side sheave (22) arranged at a piston rod-side end of the cylinder tube (9A) in the telescopic cylinder (9), and a base end (29a) of which is connected to the base-side boom ( A connecting member (29) which is arranged inside the telescopic boom (1) in the axial direction of the telescopic boom (1) while being connected to the base end (4a) of (4); 21), and has one end (23a) at the base end (6a) of the distal boom (6) and the other end (23b) at the connecting member (2).
9). The extension side wire rope (23) fixed to the tip end (29b) and the contraction side sheave (22) are wrapped around in a U-shape and one end (24a) is attached to the tip end boom (22). The other end (24b) is connected to the connecting member (2) at the base end (6a) of (6).
9) a contraction-side wire rope (24) fixed to the distal end (29b) of the intermediate boom (4) with respect to the base end boom (4) by the expansion and contraction operation of the telescopic cylinder (9). At the same time as the telescopic displacement of the intermediate boom (5), the telescopic displacement of the intermediate boom (5) is transmitted to the distal end boom (6) via the extension side wire rope (23) or the contraction side wire rope (24). A simultaneous extension / contraction mechanism of an extension / contraction boom configured to extend / contract a side boom (6) with respect to the intermediate boom (5), wherein a distal end (29b) of the connecting member (29) is attached to the extension side wire rope ( 23) and a tension adjusting means (30) for adjusting the tension of the compression side wire rope (24) are attached, and the tension adjustment means (30) is constituted by a bolt member, and the extension side wire rope is formed by a screwing operation. A first adjusting bolt () configured to be able to move the other end (23 b) of the loop (23) or the other end (24 b) of the contraction-side wire rope (24) in the axial direction of the telescopic boom (1). 36) and a hollow bolt member having a through hole (37d) penetrating through the shaft center portion, and the other end (24b) or the extension side of the contraction side wire rope (24) is formed by screwing the member. The other end (23b) of the wire rope (23) is configured to be movable in the axial direction of the telescopic boom (1), and the first adjustment bolt (3) is inserted into the through hole (37d).
6) are substantially coaxially inserted and arranged in the second adjusting bolt (3).
7), and the expanding wire rope (23) or the contracting wire rope (2) is operated by screwing the first adjustment bolt (36).
And 4) adjusting the tension and adjusting the tension of the compression-side wire rope (24) or the extension-side wire rope (23) by screwing the second adjustment bolt (37). Features a simultaneous telescopic boom telescopic mechanism.