JPH11130377A - Telescopic boom supporting structure for crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a telescopic crane boom structure capable of suppressing the section deformation of the boom and preventing an increase in the structure or weight of the boom. SOLUTION: In a telescopic crane boom supporting structure for storing the booms of plural stages inside the respective booms sequentially increased in sectional areas and extending/contracting a stored side boom 22 from a storing side boom 23 by simultaneous telescopic system using a hydraulic cylinder and wire rope, a sheave 31 around which the wire rope 30 used by the simultaneous telescopic system is wrapped is arranged inside the storing side boom 23 oppositely to the upper corner part of the stored side boom 22 in the boom tip side P1 rather than the arranging position P2 of the sheave 31 in the tip of the boom 23 provided with a rotary shaft placed in a horizontal direction, and a slide plate having a shaped to be brought into contact with the upper corner part is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a telescopic boom support structure for a crane, and more particularly, to a boom sliding guide structure.

[0002]

2. Description of the Related Art In order to secure a hanging height of a load and to reduce a protruding length during traveling, a boom of a mobile crane has a boom made of a thin box-shaped welding box having a hollow rectangular cross section. There is a configuration in which the number of stages corresponding to the amount is prepared, and the booms corresponding to the number of stages are stored in the hollow rectangular cross-section sequentially with a reduced cross-sectional area. The boom stored inside is retracted and guided by the boom on the storage side located outside the boom, so that the inner surface of the tip of the outer boom slides on the inner boom. A slide plate for guidance is arranged. The slide plate is made of a resin material such as a polyamide resin having a low coefficient of friction, and the surface thereof is disposed at a position where it can be brought into contact with the top surface or the side surface of the inner boom, and is attached to the inner surface of the boom for storage. ing. Such a slide plate has a function of sliding the inner boom smoothly and a function of suppressing cross-sectional deformation of the boom by preventing the boom from rattling in a gap between the adjacent booms together with the sliding guide of the inner boom. Also have. The slide plate is supplied with a lubricant such as grease on the contact surface with the boom for the purpose of reducing the friction coefficient when the slide plate comes into contact with the inner boom.

[0003] Therefore, in order to eliminate the welded portion of the boom corner and improve the fatigue strength and productivity, the boom corner is formed into an R shape, and a slide plate is brought into contact with the corner to oppose the top surface. A structure that combines the functions of a slide plate separately arranged on the side surface has been considered. FIGS. 4 and 5 are partial views showing a slide guide structure provided with a slide plate for the boom having the shape of the above-mentioned corner portion. In FIG. 4, for example, an intermediate part stored in the base end boom 12 is shown. Boom 1 on the storage side, like boom 11
1 has an upper corner formed in an R shape as shown in FIG. The boom 12 for storing the boom 11 to be stored is provided with a support portion for the slide plate 13 having a pad 13A that comes into contact with an upper corner of the boom 11 to be stored. As shown in FIG. 4, the support portion of the slide plate 13 includes a bracket 15 fixed to the outer surface of the boom 12 on the storage side. The support shaft 13C of the support member 13B of the pad 13A of the plate 13 is inserted. As shown in FIG.
As shown in FIG. 5, a support plate 15A is provided opposite to the side surface of the slide plate 13, and an adjustment bolt 16 for abutting the side surface of the pad 13A to swing the pad 13A is provided on the support plate 15A. Has been concluded. The pad 13A and the support member 13B, which are the main parts of the slide plate 13, can adjust the contact position of the pad 13A with the upper corner of the boom 11 on the side where the pad 13A is stored by interposing the shim 17.

[0004] In such a boom sliding guide structure, the slide plate 13 is inserted through a hole formed at a position facing the upper corner of the storage boom 11 with respect to the storage boom 12. Is supported by the pad 13A in contact with the upper corner, and the support shaft 13C is inserted into the bracket 15 and the support member 13B of the slide plate 13 so that the slide plate 13 can swing with respect to the upper corner. Is done. On the other hand, the slide plate 13 facing the upper corner portion needs to properly contact the surface of the upper corner portion. Adjustment of the gap with the surface is performed.

On the other hand, as one of the boom extension and contraction methods, there is a simultaneous extension and contraction method in which a hydraulic cylinder for expansion and contraction and a wire rope for expansion and contraction are used to simultaneously expand and contract a front end boom and a boom located at a rear end thereof. In the case of the simultaneous expansion / contraction system, the configuration shown in FIG. 6 is used as an example. FIG.
FIG. 4 is a schematic diagram for explaining an extension time of a boom using a telescopic mechanism intended for a case where a two-stage telescopic boom is used before reaching a tip boom. In the telescopic mechanism shown in FIG. 6, a front end boom 1 in a direction in which the boom extends, and a boom (hereinafter, referred to as a first intermediate boom) 2 located behind the front end boom 2.
And a boom (for convenience, referred to as a second intermediate boom) 3 located behind the first intermediate boom 2 are the objects of a telescopic boom using a wire rope. Note that reference numeral 4
The boom indicated by is a base end boom for convenience. In FIG. 6, the wire rope is composed of a tip boom 1 and a first intermediate boom 2.
And a first intermediate wire rope 6 for extending the first intermediate boom 2 are used, and one end of the distal wire rope 5 is hung on the distal end of the base end boom 4. First sheave 2A and tip boom 1 stopped near the tip of first intermediate boom 2
The first end of the first intermediate boom 2 is hooked on the front end of the first intermediate boom 2 after being hung around the front end sheave 1A located near the rear end. The first intermediate wire rope 6 is hung on the distal end of the base end boom 4, and is hung around the second sheave 3 </ b> A located near the distal end of the second intermediate boom 3, and then the rear end of the first intermediate boom 2. Is hooked at the other end.

The second intermediate boom 3 can be extended and retracted by a telescopic hydraulic cylinder 7 disposed in the base end boom 4, and when the telescopic hydraulic cylinder 7 is extended, it is extended in conjunction therewith. . When the second intermediate boom 3 is extended, the second sheave 3A moves in the extension direction, so that the other end of the first intermediate wire rope 6 wrapped around the second sheave 3A is hooked to the rear end. One intermediate boom 2 moves in the extension direction in conjunction with it. When the first intermediate boom 2 moves in the extending direction, the first intermediate boom 2 moves to the first
Since the sheave 2A moves in the extension direction, the tip sheave 1A around which the tip wire rope 5 is wound also moves in the extension direction, and the tip boom 1 moves in the extension direction.

[0007]

The following problems arise when the boom sliding support structure shown in FIGS. 4 and 5 is applied to a boom using such a telescopic mechanism. In the case of the first intermediate boom 2, for example, the wire rope used to extend and retract the boom is wrapped around the first sheave 2A located at the tip of the first boom 2 and folded by the first sheave 2A. A portion extending from the lower peripheral surface of the first sheave 2 </ b> A is located near the lower end of the slide plate 13. For this reason, in order to prevent interference with the wire rope 5 for the distal end, it is necessary to shorten the length of the vertical portion of the slide plate 13. If the vertical piece of the slide plate 13, that is, the piece that faces the side of the boom 11 on the side where it is stored is short, the contact surface between the side of the boom 11 and the side where the boom 11 is stored is reduced. The supporting range for the side surface of the boom 11 on the side of the boom becomes insufficient, and it becomes difficult to prevent bending deformation of the boom in the lateral direction. In addition, since the first sheave 2A around which the wire rope is wound is positioned behind the leading end of the first intermediate boom 2 so as not to protrude from the end of the boom, the mounting position of the slide plate 13 is set. Is positioned rearward of the first sheave 2A from the tip of the first intermediate boom 2. For this reason, with respect to the maximum extension length of the boom determined by the length between the slide plate 13 and another slide plate provided at the rear end of the boom, the slide plate 13 is located behind the first sheave 2A. Therefore, the maximum elongation length becomes short, so that the so-called wrap length cannot be set large.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the conventional support structure of a telescopic boom, an object of the present invention is to provide a crane having a structure capable of suppressing cross-sectional deformation of the boom and preventing an increase in the structure and weight of the boom. It is to provide a boom support structure.

[0009]

In order to achieve this object, according to the first aspect of the present invention, a boom having a plurality of stages is housed inside each of the booms having a sequentially increased sectional area, and a hydraulic cylinder and a wire rope are connected to each other. It is a telescopic boom support structure of a crane that expands and contracts the stored boom from the retracted boom using the simultaneous telescopic method, in which a sheave for hanging a wire rope used in the simultaneous telescopic method rotates. At the end of the boom provided with the axis in the horizontal direction, it is located inside the boom on the storage side opposite to the upper corner of the boom on the storage side at the boom tip side from the disposition position of the sheave. And a slide plate having a shape capable of contacting the upper corner portion is provided.

According to a second aspect of the present invention, in the telescopic boom support structure for the crane according to the first aspect, the boom has an upper corner formed in an R shape, and the slide plate has an R shape formed in the upper corner. Among them, the length of the surface facing the boom side surface is longer than the length of the surface facing the boom upper surface.

According to a third aspect of the present invention, there is provided a boom in which a plurality of stages of booms are stored inside each of the booms having sequentially increased cross-sectional areas, and are stored by a simultaneous expansion and contraction method using a hydraulic cylinder and a wire rope. Is a telescopic boom support structure of a crane for extending and retracting from a boom on the side of storing, wherein a sheave for hanging a wire rope used in the simultaneous telescopic system is provided with a rotation axis in a horizontal direction. At the tip, the boom is located inside the storage boom opposite the top and left and right sides and the upper side of the storage side boom on the boom tip side with respect to the position of the sheave, and the top and left and right sides and side surfaces A slide plate having a contactable shape is provided on the upper part.

[0012]

According to the first to third aspects of the present invention, it is possible to abut on the upper corner of the boom on the side where the wire rope for the simultaneous expansion and contraction system is retracted, at the end of the boom with respect to the position where the wire rope is wound. Since the slide plate having a suitable shape is arranged, the slide plate can be installed regardless of the position of the wire rope projecting from the lower peripheral surface of the sheave by being wrapped around the sheave and folded back.
In particular, according to the first and second aspects of the present invention, the slide plate having a shape capable of contacting the upper corner portion has a length corresponding to a length of a vertical surface in the shape of the wire which is folded back by the sheave and protrudes from the lower peripheral surface of the sheave. Since it does not interfere with the rope, it can be set to a length capable of suppressing the lateral deflection of the side surface of the boom. The length of the slide plate in the vertical direction can be set to a length that can prevent lateral bending of the boom side surface irrespective of the slide plate for the right and left top surfaces.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a view showing a distal end portion of a telescopic boom to which a telescopic boom support structure according to an embodiment of the present invention is applied. In the drawing, in this embodiment, a base end boom 20 having an undulating fulcrum on a swivel (not shown) is shown. First to fourth intermediate booms 23 between the front end boom 22 having the boom head 21;
24, 25 and 26 are provided. As described in the prior art, each boom is formed in a hollow substantially rectangular cross-section having an upper corner formed in an R shape, and the cross-sectional area is gradually reduced toward the tip boom 22 and the boom located at the rear thereof. Is stored within. Base boom 20, excluding distal boom 22, first to fourth intermediate booms 23, 24, 25, 2
6, a support bracket 27 having an upright piece is fixed to the outer surface of the distal end portion.
A support portion for a slide plate 28 described later is provided.

In this embodiment, the support bracket 27 is
The structure is such that the slide plate 28 can be supported at a position that does not interfere with the wire rope used in the simultaneous expansion / contraction system. That is, in FIG. 1, the wire rope 30 used in the simultaneous expansion and contraction method is located near the upper corner of the boom on the side where it is stored, and there is a possibility that the wire rope 30 may interfere with the slide plate 28 arranged symmetrically with the upper corner. Boom is first
The intermediate boom 23 corresponds. For this reason, the first intermediate boom 23 is provided at the installation position of the first intermediate boom 23 provided with the sheave 31 having the same function as the first sheave 2A shown in FIG. On the other hand, a support bracket for attaching the slide plate 28 (for convenience, a support bracket for the first intermediate boom 23 is indicated by reference numeral 27A in FIG. 1) is located on the first intermediate boom 23 more than the installation position of the sheave 31. The slide plate 28 is provided so that the slide plate 28 can be arranged at the front end side (position indicated by reference numeral P2 in FIG. 1), preferably at the front end.

On the other hand, FIG. 2 shows the relationship between the booms on the storage side and the boom on the storage side, and FIG. 2 shows the tip boom 22 corresponding to the boom on the storage side and the boom on the storage side. The corresponding relationship with the first intermediate boom 23 corresponding to. With respect to the configuration of the support portion of the slide plate, the other booms have the same relationship. FIG.
In the first intermediate boom 23 corresponding to the storage-side boom, the adjustment bolts 32, 3 are located at positions facing the upper corners of the tip boom 22 corresponding to the storage-side boom.
3 are arranged. The adjustment bolt 32 is a vertical piece 2 of the support bracket 27 that faces the boom side face.
7A is fastened to the fastening plate 27A1 provided in the axial direction,
That is, the adjustment bolt 33 is capable of moving back and forth in the horizontal direction of the boom, and the adjustment bolt 33 is fastened to a fastening plate 27B1 provided in the horizontal direction with respect to the vertical piece 27B facing the upper surface of the boom among the pieces of the support bracket 27. In the axial direction, that is, in the vertical direction of the boom. Fastening plates 27A1, 2
7B1 is provided with a screw hole, and adjustment bolts 32 and 33 are fastened to the screw hole and are prevented from rotating by a nut 50 (see FIG. 3). The amount of advance / retreat can be changed by changing the amount of fastening. It has become. These adjusting bolts 32 and 33 can be brought into contact with the horizontal and vertical edges of a pad 28A of the slide plate 28 described later, whereby the pad is moved from the upper corner surface of the stored boom to the pad. The horizontal and vertical edges of the 28A can be prevented from rising.

As shown in FIG. 3, the slide plate 28 is composed of a pad 28A and a pad 28A having a contact surface aligned with the R-shape of the upper corner of the boom with a polyamide resin.
And a metal retainer 28B serving as a support portion for the A. The pad 28A is provided with a split pin 28D inserted into a concave portion 28C formed substantially at the center of the contact surface with the upper corner portion. It is prevented from falling by hooking. The pad 28A has a length (a length indicated by reference numeral L1 in FIG. 3) of a surface facing a side surface of a boom (a tip boom indicated by reference numeral 22 in FIG. 3) in an R shape which is a shape of an upper corner portion. Is the length of the surface facing the upper surface of the boom 22 (in FIG.
2). For this reason, of the adjustment bolts described above, the boom on the storage side (FIG. 3)
The first and second adjustment bolts 32, which are movable in the horizontal direction with respect to the first intermediate boom denoted by reference numeral 23, press two positions of the pad 28A in the vertical direction. It is positioned near the edge. The first intermediate boom 23 on the storage side has a slide plate 2 at a position corresponding to the upper corner of the tip boom 22 on the storage side as shown by reference numeral 23A in FIG.
An insertion hole having a shape in which the insertion hole 8 can be inserted is formed.

Since the present embodiment has the above configuration,
As shown in FIG. 1, the slide plate 28 faces the upper corner of the tip end boom 22 on the boom tip side (P2) with respect to the position (P1) of the sheave 31 of the first intermediate boom 23. The pad 28A
Is in contact with the upper corner. Support bracket 27
As shown in FIG. 1, the slide plate 28 inserted at a position irrelevant to the position of the wire rope 30 projecting from the lower peripheral surface of the sheave 31 interferes with the wire rope 30. Installed without any

On the other hand, a fastening plate 27 formed on a support bracket 27 provided on the first intermediate boom 23 on the storage side.
Adjustment bolts 32 and 33 are fastened to A1 and 27B1, respectively, and are moved straight forward and backward so that the tips thereof come into contact with the back surface of the retainer 28B of the slide plate 28.

The slide plate 28 advances and retreats the adjustment bolts 32 and / or 33 to the upper corner of the tip end boom 22 on the side to be stored, and aligns the pad 28A with the R-shape of the upper corner to make close contact. As a result, the gap between the upper corner portion of the tip boom 22 on the storage side and the inner surface of the first intermediate boom 23 on the storage side can be filled to prevent backlash of the tip boom 22 on the storage side. State. Although not shown, grease is filled between the pad 28A and the surface of the upper corner portion of the slide plate 28 which is in close contact with the upper corner portion of the tip end boom 22 to be stored, and Allow sliding.

It should be noted that the slide plate is not limited to being provided for the upper corner formed in the R-shape on the boom on the side where it is stored as described in the above embodiment. In addition to the upper corner, it is also possible to arrange the top left and right portions and the upper side surface. Also in this case, the position where the slide plate is provided is set closer to the boom tip (P2) than the position (P1) where the sheave 31 is installed. Therefore, according to such a configuration, the wire rope 30 protruding from the lower peripheral surface of the sheave 31 does not interfere with the slide plate facing and abutting against the side surface of the tip boom 22. The length in parallel with the side surface of the tip boom 22 can be set to a length sufficient to suppress the lateral deflection of the tip boom 22. Such a type in which the slide plate is abutted on the left and right portions of the top surface of the boom and the upper portion of the side surface of the boom includes a case where the boom is a box-shaped welded structure having a hollow rectangular cross section. Further, the sheave 31 described in the above embodiment is used.
This includes not only the case where the pivot direction is not only the horizontal direction but also the direction inclined at an angle with respect to the horizontal plane. It is needless to say that the present invention is not limited to the above embodiment as long as the structure extends from the surface.

[0021]

As described above, according to the first to third aspects of the present invention, the slide plate having a shape capable of abutting on the upper corner of the boom on which it is stored is a slide plate for simultaneous expansion and contraction. Since the wire rope is located on the boom tip side from the position where the sheave is hung, it slides regardless of the position of the wire rope that projects from the lower peripheral surface of the sheave by being hung around the sheave and folded back Plates can be installed. In particular, claims 1 and 2
According to the described invention, the slide plate having a shape capable of abutting the upper corner portion interferes with the wire rope that is folded back by the sheave and protrudes from the lower peripheral surface of the sheave with respect to the length of the vertical surface in the shape. Since there is no
According to the third aspect of the present invention, the length of the slide plate disposed on the upper side of the boom on the side where the boom is stored can be set to a length capable of suppressing the lateral deflection of the boom side. The length of the boom can be set to a length that can prevent lateral bending of the boom side surface irrespective of the slide plate intended for the left and right sides of the top. Thereby, the cross-sectional deformation of the boom can be suppressed, and the structure and weight of the boom can be reliably prevented from increasing.

[Brief description of the drawings]

FIG. 1 is a side view showing a tip position of a boom to which a support structure for a telescopic boom according to an embodiment of the present invention is applied.

FIG. 2 is a partial cross-sectional view of a main part of a support structure according to an embodiment of the present invention, as viewed from the front of a boom.

FIG. 3 is an enlarged view of a main part structure shown in FIG. 2;

FIG. 4 is a side view of a boom tip for explaining a conventional example of a telescopic boom support structure.

FIG. 5 is a partial cross-sectional view of the front end of the boom for explaining a structure of a support portion of a slide plate provided at the front end of the boom shown in FIG. 4;

FIG. 6 is a schematic diagram for explaining an outline of a simultaneous expansion / contraction system.

[Explanation of symbols]

22 Front end boom corresponding to one of the stored booms 23 First intermediate boom corresponding to one of the stored booms 27 Support bracket 27A Support bracket provided on the first intermediate boom 28 Slide plate 28A Pad 28B Retainer 30 Wire rope used for simultaneous expansion / contraction system 31 Sheave around which wire rope is wound 32, 33 Adjusting bolt L1 Length of surface of slide plate opposite to boom side surface L2 Length of surface of slide plate opposite to boom upper surface Length P1 Position of the support bracket for the slide plate P2 Position of the wire rope sheave used for the simultaneous expansion and contraction method

Claims (3)

[Claims] A boom having a plurality of stages is sequentially stored inside each of the booms having a larger sectional area, and a hydraulic cylinder and a wire rope wrapped around a sheave arranged at the end of the boom which is extended and retracted by the hydraulic cylinder are used. The crane is a telescopic boom support structure for extending and retracting the boom on the side stored in the retractable boom from the boom on the side in which the retractable boom is stored. At the end of the boom, it is disposed inside the boom on the storage side, facing the upper corner of the boom on the storage side at the boom tip side from the disposition position of the sheave, and can contact the upper corner. A crane telescopic boom support structure comprising a slide plate having a simple shape. 2. The telescopic boom support structure for a crane according to claim 1, wherein the boom has an upper corner formed in an R-shape, and the slide plate has an R-shape in the upper corner.
A telescopic boom support structure for a crane, wherein a length of a surface facing the boom side surface is longer than a length of a surface facing the boom upper surface. 3. A multi-stage boom is sequentially stored inside each of the booms having a larger cross-sectional area, and a hydraulic cylinder and a wire rope wrapped around a sheave arranged at the end of the boom which is extended and contracted by the hydraulic cylinder are used. The crane is a telescopic boom support structure for extending and retracting the boom on the side stored in the retractable boom from the boom on the side in which the retractable boom is stored. At the end of the boom, the boom is located inside the boom on the storage side facing the left and right top surface and the upper side of the boom on the storage side on the boom tip side from the arrangement position of the sheave. A telescopic boom support structure for a crane, wherein a slide plate having a shape that can be abutted is provided on a part and an upper part of a side surface.