JPH09151080A - Boom tail slider - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boom tail slider capable of forming a lightweight extensible/contractible boom which is stable in strength. SOLUTION: A boom tail slider composed of upper surface sliders 43 and 44 and side surface sliders 45 and 46, is installed on an upper surface of an intermediate boom member 42. Since the side surface sliders are positioned so as to slightly separate to the tip side from the upper surface sliders installed on the base end side (on this side in a drawing), the bending moment acts on a boom, and when thrusting-up force acts on a base end boom member 41 through the upper surface sliders 43 and 44 from a tail part of the intermediate boom member 42, elastic deformation of the base end boom member 41 is allowed, and internal stress is restrained small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom tail slider provided on a telescopic boom provided in a work platform, a crane truck or the like.

[0002]

2. Description of the Related Art An aerial work vehicle is used for performing aerial work such as power distribution work. In general, a boom that can freely turn, undulate, expand and contract, and the like is provided on a movable vehicle body. The work table is provided at the tip. In high-place work, after the boom is swung, raised and lowered, and the work table is moved to an arbitrary high position, the worker on the work table performs desired work.

[0003] This telescopic boom has a telescopic boom member and can be telescopically operated by a hydraulic cylinder or the like provided in the boom. The boom member generally includes an outer boom member having a prismatic space, and an inner boom member inserted into the space, and a slider member provided as a buffering and lubricating means on the outer surface of the inner boom member. The inner boom member is configured to slide smoothly in the longitudinal direction on the inner surface of the outer boom member.

When such a boom is operated, as shown in FIG. 6, the bending moment is calculated from the weight F of the work table 117 disposed at the tip of the inner boom member 142 and the weight of the worker M who rides on the work table. Acts on members. (While the weight of the inner boom member itself also plays a role, it is omitted here for the sake of simplicity.) In addition, the work table 117 is swung right and left with respect to the boom extension direction. ,
Due to the movement of the worker M in the work table 117, a torsion moment also acts.

[0005] The arrangement of the slider member on the telescopic boom can be achieved by a conventional method at the tail portion of the inner boom member as shown in FIG.
This is often done as shown in In order to obtain a smooth expansion and contraction operation while preventing rotation due to a torsional moment, the vicinity of each corner of the outer boom member is efficiently slid by the slider in the same plane perpendicular to the boom longitudinal direction. Specifically, the sliders 143 and 144 arranged on the left and right corners of the upper surface of the inner boom member 142 are
The upper surface slides on the inner surface of the upper wall of the outer boom member 141,
The outer side surface is in sliding contact with the inner surface of the upper side wall of the outer boom member. The sliders 147 and 148 disposed on the lower corners of the left and right side surfaces of the inner boom member 142 are in sliding contact with the inner surface of the lower wall of the outer boom member 141 on the lower surface thereof, and the lower portion of the outer boom member on the outer side surface. It is in sliding contact with the inner surface of the side wall.

By the way, as shown in FIG. 6, when the inner boom member 142 is extended with respect to the outer boom member 141 and the extension distance 1 increases, the weight F of the work table 117 on which the worker M is mounted is reduced. The bending moment, which is a product of the extension distance l, increases in proportion to the increase in the extension distance l.
This increase in bending moment suppresses the drag acting from the outer boom member 141 via the sliders 143 and 144 disposed on the upper surface of the tail portion of the inner boom member 142, that is, suppresses the tail portion of the inner boom member 142 from being pushed up. This causes an increase in the thrust reaction force R2 generated as a reaction. This pushing-up reaction force R2 is such that when the extension distance l increases, the distance a between the inner boom member tail portion and the outer boom member front end opening decreases by the increase of the extension distance l.
Increase significantly.

[0007] As shown in FIG. 5, the outer boom member 141 is positioned at the upper left and right corners of the outer boom member 141 to prevent the outer boom member from being fatigued or damaged due to the internal stress generated in the outer boom member 141 due to the thrusting reaction force R2. Conventionally, reinforcing members 141a and 141 obtained by bending a band-shaped plate material into an L-shape are provided.
b is attached.

[0008]

However, such reinforcement of the outer boom member is not preferable because the number of manufacturing steps increases and the production cost increases. In addition, the boom weight increases by the amount that the reinforcing material is attached to the outer boom member,
There is also a problem that the body weight increases. The present invention
The present invention has been made in view of such a problem, and an object thereof is to provide a boom tail slider that enables a lightweight telescopic boom with stable strength.

[0009]

SUMMARY OF THE INVENTION A boom tail slider according to the present invention relates to a slider member provided between an outer boom member and an inner boom member in a telescopic boom. A slider to be attached. In order to achieve the above object, a boom tail slider according to the present invention includes an upper slider slidably in contact with an inner surface of an upper wall forming a prismatic space of an outer boom member, and an upper side wall forming a prismatic space of the outer boom member. The upper surface slider and the side surface slider are attached to the upper part of the inner boom member tail portion in the longitudinal direction so as to be separated from each other in the longitudinal direction.

[0010]

When a bending moment acts on the boom due to a vertical load acting on the tip of the inner boom member, a force is generated at the rear end of the inner boom member inserted into the outer boom member to push up the outer boom member. This pushing-up force pushes up the upper wall of the outer boom member, and acts from the inner boom member to the outer boom member via an upper surface slider disposed above the tail portion of the inner boom member. As a reaction to the pushing force, a pushing reaction force is generated on the upper wall of the outer boom member to which the upper surface slider is slid.

The internal stress generated in the outer boom member in response to the upward reaction force is efficiently suppressed by the boom tail slider of the present invention, which is configured to allow the outer boom member to elastically deform. In detail, since the upper surface slider and the side surface slider are disposed in the upper portion of the inner boom member tail portion in the longitudinal direction and separated from each other, the upper surface slider and the side surface slider are separated from the inner boom member via the upper surface slider disposed on the upper portion of the inner boom member tail portion. When a pushing force acts on the outer boom member, the upper wall of the outer boom member can bend upward, and the left and right side walls of the outer boom member can bend inward of the outer boom member. Due to the relatively free elastic deformation of the outer boom member, the internal stress of the outer boom member is relatively small.

In the conventional tail slider, since the upper surface and the side surface are slid on the same plane of the boom section, elastic deformation of the outer boom member is suppressed. Is because the top slider and the side slider were arranged apart in the longitudinal direction,
Elastic deformation is relatively free.

As described above, according to the boom tail slider of the present invention, the internal stress can be kept relatively small by the elastic deformation of the outer boom member. The member can sufficiently tolerate the push-up reaction force. Therefore, it is possible to reduce the manufacturing cost of the telescopic boom by omitting the manufacturing process for reinforcing the outer boom member. Further, if the reinforcing member is removed from the outer boom member, the boom weight is reduced, and the vehicle body weight is also reduced. Alternatively, it is also possible to realize a boom capable of withstanding a larger thrust reaction, that is, a boom having a larger maximum allowable load, by using the outer boom member having the same plate thickness as that of the related art.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows an aerial work vehicle 10 on which a boom 40 including the boom tail slider of the present invention is disposed. This aerial work vehicle 10 generally includes a vehicle body portion and a boom portion. The vehicle body portion is mainly composed of a self-propelled vehicle body 11 having drive wheels, and jack devices 19 are provided on the front, rear, left and right of the vehicle body 11 to extend and contact the ground to stably support the vehicle body 11 during work. I have.

A built-in motor (not shown) is mounted on the vehicle body 11.
A swivel 12 is provided so as to be rotatable. A boom 40 is pivotally supported on the upper surface of the swivel base 12, and an up-and-down cylinder 14 is fixed to the boom 40 from the swivel base 12. The boom 40 can freely move up and down through the expansion and contraction operation of the up and down cylinder 14. The boom 40 includes a base boom member 41, an intermediate boom member 42, and a distal boom member 43, which are telescopically assembled, and is telescopically operated by a telescopic cylinder (not shown) provided in the boom. It is free.

A vertical post 16 is pivotally supported at the distal end of the distal end boom member 43. The vertical post 16 is connected to the leveling cylinder 1 regardless of the up / down state of the boom 40.
5 keeps it always vertical. Further, a work table 17 is attached to the vertical post 16 so that the work table 17 can swing freely in the horizontal direction. At the time of working at a high place using the aerial work vehicle 10, the worker M rides on the working table 17 and turns the boom 40, raises and lowers and extends the work table 17 to move to the desired higher position. I do. If necessary, the work table 17 is also swung, and after the work table 17 is positioned, a desired work is performed by the worker M who is on the work table 17.

The boom tail slider of the present invention is disposed within a boom 40, and an intermediate boom member 42 is provided inside a base end boom member 41, and a distal end boom member 43 is provided inside the intermediate boom member 42. Is installed in a telescopic manner via a slide member as a buffering and lubricating means, and is attached to the tail portion of the distal boom member 43 or the intermediate boom member 42.

FIG. 1 shows a tail portion of an intermediate boom member 42 which is inserted into a base boom member 41 of the boom 40 of FIG. In this case, the intermediate boom member 42 becomes the inner boom member, and the proximal boom member 41 becomes the outer boom member. Via a slider member (not shown) disposed at a distal opening of the base end boom member 41 and sliders 43 to 48 disposed at a tail portion of the intermediate boom member 42,
The intermediate boom member 42 slides smoothly with respect to the proximal boom member 41. Therefore, the intermediate boom member 42 and the proximal end boom member 41 preferably have similar shapes in cross section, and may be formed by extrusion from aluminum or the like.

The boom tail slider of the present invention disposed on the upper surface of the tail portion of the intermediate boom member 42 comprises upper surface sliders 43 and 44 and side sliders 45 and 46, and both the upper surface slider and the side surface slider have a rectangular parallelepiped shape. Formed. However, the upper sliders 43 and 4
4 is higher than the side sliders 45 and 46, and the side slider is formed wider than the upper slider.

As shown in FIG. 1, both the upper sliders 43 and 44 and the side sliders 45 and 46 are symmetrically mounted along the longitudinal direction near the upper surface and the left and right side surfaces of the intermediate boom member 42. Side sliders 45 and 46 are attached slightly away from the top sliders 43 and 44 attached to the sides (front side in the figure) toward the distal end. In this embodiment, the intermediate boom member 42
Lower sliders 47 and 48 are provided at lower portions on the left and right side surfaces of the tail portion.

Next, the sliding contact between the sliders 43 to 48 disposed on the tail portion of the intermediate boom member 42 and the base end boom member 41 will be described with reference to FIGS. As shown in FIG. 2, the upper surface sliders 43 and 44 are mounted on the upper surface of the intermediate boom member 42 with their respective side surfaces located at the right and left corners of the upper surface of the intermediate boom member 42. In the vicinity of the upper inner corner, the base boom member 41 is slid in contact with the inner surface of the upper wall at a predetermined distance from the left and right side walls.
The lower sliders 47 and 48 are connected to the intermediate boom member 4.
2, the lower slider 47 is slidably contacted with the lower left side and the lower left wall near the lower left inner corner of the base end boom member 41, and the lower slider 48 is mounted on the base end boom member 4.
1 is slidably in contact with the lower right side inner corner, lower wall and lower part of the right side wall.

As shown in FIG. 3, the side sliders 45 and 46 are slidably contacted with the right and left corners of the upper surface of the intermediate boom member 42, in the vicinity of the upper left and right inner corners of the base end boom member 41, and on the upper side wall. To be mounted. Side slider 4
5 and 46 are lower in height but longer in width than the upper sliders 43 and 44, so that the side sliders 45 and 46 do not slide on the inner surface of the upper wall of the base end boom member 41. The intermediate boom member 42 is formed by these side sliders 45 and 46 and lower sliders 47 and 48.
Is prevented from rotating with respect to the proximal end boom member 41.

Next, a case where a bending moment acts on the boom 40 and a pushing force acts on the boom tail slider of the present invention will be described. When the worker M rides on the work table 17 and the boom 40 is extended, a bending moment acts on the boom 40 due to a vertical load from the work table 17. At this time, the bending moment causes the upper surface sliders 43 and 44 to move from the tail portion of the intermediate boom member 42.
A push-up force acts on the base end boom member 41 via the. FIG.
As can be seen from FIG. 4, since the outer sides of the upper surface sliders 43 and 44 are not in contact with the inner surface of the side wall of the proximal end boom member 41, the proximal end boom member 41 is relatively freely elastically deformed by this pushing-up force. The upper wall of the proximal boom member 41 is curved so as to float upward a, and the side wall is also curved inwardly b and c.

As described above, the boom tail slider of the present invention allows the base end boom member 41 to elastically deform.
The internal stress withstanding the thrust reaction force generated in the base end boom member 41 as a reaction force to the thrust force can be relatively suppressed. For this reason, the base end boom member 41 has improved durability against fatigue and breakage, and also realizes a boom that can withstand a larger thrust-up reaction force.

In the above embodiment, one upper surface slider of the boom tail slider is provided at each of the right and left corners of the upper surface of the intermediate boom member 42. However, the present invention is not limited to this. You may comprise so that it may cover the whole upper surface, or may arrange | position one piece in an intermediate part.
Further, the side slider may be attached to the upper part of the left and right side surfaces of the intermediate boom member 42. In the above embodiment, only the intermediate boom member 42 and the proximal boom member 41 have been described, but the relationship between the distal boom member 43 and the intermediate boom member 42 is the same, and furthermore, the boom members are stacked in several stages. It can also be used in multi-stage booms.

[0026]

As described above, according to the boom tail slider of the present invention, the upper surface slider and the side surface slider disposed above the tail portion of the inner boom member are separated from each other in the boom longitudinal direction. When a bending moment acts on the entire boom and a thrust force acts from the inner boom member to the outer boom member via the upper surface slider, the upper wall of the outer boom member curves upward and the left and right side walls curve inward.
Due to this elastic deformation, the internal stress of the outer boom member is kept relatively small.

In the conventional tail slider, the sliding of the upper surface and the sliding of the side surface are performed on the same plane of the boom cross section, so that the inward bending of the left and right side walls of the outer boom member is suppressed. However, in the boom tail slider of the present invention, since the elastic deformation is relatively freely allowed and the internal stress is suppressed as compared with the conventional one, the boom tail slider of the present invention can be used without the reinforcement conventionally applied to the outer boom member. The slider allows the outer boom member to sufficiently push up the reaction force. Therefore, the manufacturing process for reinforcing the outer boom member can be omitted, and the production cost can be reduced. Also, if the reinforcing member is removed from the outer boom member, the boom weight is reduced, and the weight of the entire vehicle body is also reduced. Further, by using the outer boom member having the same plate thickness as that of the related art, it is possible to realize a telescopic boom that can withstand a larger push-up reaction force, that is, a telescopic boom having a larger maximum allowable load.

[Brief description of the drawings]

FIG. 1 is a perspective view of an intermediate boom member provided with a boom tail slider of the present invention.

FIG. 2 is a cross-sectional view of a boom in which the intermediate boom member is inserted into a base end boom member at a position of an upper surface slider.

FIG. 3 is a sectional view of the boom at a position of a side slider.

FIG. 4 is a side view of an aerial work vehicle provided with the boom tail slider of the present invention.

FIG. 5 is a sectional view of a boom showing a conventional tail slider.

FIG. 6 is an explanatory diagram of a bending moment acting on a boom.

[Explanation of symbols]

 Reference Signs List 10 aerial work vehicle 11 body 12 turning table 17 work table 40 boom 41 base end boom member 42 intermediate boom member 43 upper surface slider 45 side surface slider

Claims (1)

[Claims] An outer boom member having a prismatic space, an inner boom member having a prismatic outer shape nested in the prismatic space and slid in the longitudinal direction, and an outer surface of the inner boom member A boom tail slider disposed above the inner boom member tail portion of a telescopic prismatic boom comprising a slider member disposed between the outer boom member and an inner surface of the outer boom member. An upper surface slider slidably in contact with the inner surface of the upper wall forming the prismatic space, and a side slider slidably in contact with the inner surface of the upper side wall forming the prismatic space of the outer boom member. A boom tail slider, wherein a position at which the side slider is disposed is separated from a position at which the side slider is disposed in a longitudinal direction of the inner boom member.