JP2000139573A - Telescopic device with rotation prevention mechanism - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent rotation even when a round gas spring is used, to simplify the structure and reduce the cost. The telescopic device includes a support member (for example, a support), which is formed of at least a double cylinder, which is fitted to extend and contract, and a gas spring (15) built in the support member and extending and contracting the support member. The inner member 22 of the member 2 is formed of a member having a non-circular cross-sectional profile, has a slide bearing surface 24 c having the same shape as the cross-sectional profile of the inner member 22, and has an outer surface of the support member 2. At least one slide bearing 24 fixed to the member 21 and slidably supporting the inner member 22 is provided, and the inner member 22 is provided with a bearing surface 24 c of an inner peripheral surface of the slide bearing 24.
While slidingly contacting the outer member 21 so as to be non-rotatable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic device with a rotation preventing mechanism suitable for a chair or a table. More specifically, the present invention relates to an improvement of a telescopic device with a rotation preventing mechanism used for adjusting the height of a top plate at a table, for example.

[0002]

2. Description of the Related Art A telescopic device using a gas spring is sometimes used as a lifting mechanism for a chair or a table. For example, a gas spring is built in a column constituting a leg of a chair, and a lower end of the gas spring is fixed to the leg side and an upper end is fixed to a seat receiving member on the seat side, and a gas connecting the leg and the seat receiving member is provided. The seat is moved up and down by expansion and contraction of a spring. Also, when adjusting the height of the table top, a telescopic device incorporating a gas spring is used as a lifting mechanism. In this case, the gas spring is attached so as to connect the top plate and the legs, and positions the height of the top plate. In these cases, it is supported by a single column arranged in the center of the seat or the top plate, or by two columns arranged on the left and right of the top plate,
As the gas spring, a generally commercially available gas spring is used.

On the other hand, there are cases where a leg and a support are arranged only at one end of the table and the table is cantilevered by one support. In this case, a T-shaped leg consisting of a leg extending in the front-rear direction at one end of the table and an auxiliary leg extending perpendicularly to the table and below the table is employed to provide a well-balanced support so that the table does not fall. Have been. However, in such a table, if the telescopic device constituting the column is rotatable, when the table turns in a direction opposite to the direction in which the auxiliary legs protrude, the table falls over. It is necessary to restrain the top plate so that it cannot rotate around the column. In addition, providing the rotation restricting means so as to be exposed between the table top and the like and the support column impairs the appearance and lowers the commercial value.

[0004] Therefore, it is desired that the expansion / contraction device itself cannot be rotated. In order to prevent the rotation of the support member while keeping it stretchable with a simple structure, for example, use a gas spring with a non-circular appearance, such as a square or hexagonal shape, around the support when the top plate is used or when lifting and lowering It is conceivable to prevent rotation.

[0005]

However, commercially available gas springs that are readily available are generally circular,
It has a non-circular appearance such as a square or hexagonal shape and the required length,
It is difficult to obtain a gas spring with a diameter. Further, there is a problem that even if such a specially shaped gas spring is manufactured, it becomes expensive.

Accordingly, an object of the present invention is to provide a telescopic device with a rotation preventing mechanism that does not rotate even when a round gas spring is used.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a support member comprising at least a double cylinder which is telescopically fitted and a support member built in the support member. And a gas spring that expands and contracts, wherein the inner member of the support member is formed of a member having a non-circular cross-sectional profile, and has a slide bearing surface having the same shape as the cross-sectional profile of the inner member. At least one slide bearing fixed to the outer member of the support member and slidably supporting the inner member is provided, and the inner member slides against the inner peripheral surface of the slide bearing with respect to the outer member. It relatively slides so that it cannot rotate.

In this case, the slide bearing is integrally mounted on the outer member so as not to rotate, and the hole is formed in a non-circular shape corresponding to the inner member. For this reason, the non-circular member is prevented from rotating around the axis by the slide bearing, and can be slid only in the axial direction with respect to the outer member. Further, when the slide bearing is formed of a member different from the outer member, the slide member can be attached after the inner member is inserted into the outer member, and the work of attaching and detaching the inner member is simplified.

According to a second aspect of the present invention, in the telescopic device with a rotation preventing mechanism according to the first aspect, an end portion of the inner member that is always occupied in the outer member is slidably in contact with an inner peripheral surface of the outer member. Placing the sliding bearing supported by the member,
At the end of the outer member to which the inner member enters and exits, the outer member has a slide bearing surface having the same shape as the cross-sectional profile of the inner member, and is fixed to the outer member of the support members to slidably support the inner member. A plain bearing is arranged so that the inner member and the outer member are supported at at least two places. For this reason, when the inner member slides, the shaft is less likely to shake with respect to the outer member, and the support member can be expanded and contracted while the center axes of the two members are aligned.

According to a third aspect of the present invention, the inner member of the telescopic device with a rotation preventing mechanism according to the first or second aspect is a square pipe. In this case, rotation of the inner member can be prevented by using an inexpensive pipe that can be formed relatively easily than pipes of other shapes, so that a telescopic device with a rotation prevention mechanism can be realized at low cost.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

FIGS. 1 to 13 show an embodiment of a cantilever typing table (hereinafter simply referred to as a table) to which a telescopic device with a rotation preventing mechanism according to the present invention is applied. The table 1 in this embodiment is used, for example, for typing. One table 2, a fixing member 4 attached to the top of the column, and a table 1 horizontally protruded from the column 2 and the fixing member 4. It is composed of a rotation center shaft 3, a top plate 5 rotatably supported by the rotation center shaft 3, and legs 6 for supporting the top plate 5 so as not to overturn. A movable top plate 5 is supported by the rotation center axis 3 so as to be rotatable around the axis, and is provided so that the angle can be adjusted and fixed at an arbitrary angle. In this embodiment,
Since the fixing member 4 also functions as a top plate, the fixing member 4 and the movable top plate 5 constitute a substantial top plate. Therefore, hereinafter, the fixing member 4 is also referred to as a fixed top plate or simply a top plate.

A support member (hereinafter, referred to as a support column) 2 constituting a support column is a member having a double cylindrical structure of an outer member 21 and an inner member 22 and capable of expanding and contracting. In the present embodiment, FIG.
As shown in FIG. 2, a cylindrical member forming the lower side of the column 2 (hereinafter referred to as a “lower column”) is adopted as the outer member 21 of the column 2, and the upper side of the column 2 is formed as an inner member 22 of the column 2. Pipe (hereinafter referred to as "upper support"). As shown in FIG. 4, the telescopic device is provided with a lower support 21 and an upper support 22 and a gas spring 15 which connects and operates the lower support 21 and the upper support 22 so as to be vertically expandable and contractible. Can be arbitrarily adjusted. As shown in FIG. 2, the leg 6 is attached to the lower support 21 of the support 2 by welding or the like. The leg 6 is, as shown in FIGS.
Support member 61 fixed to the bottom of the base by welding or the like
And an auxiliary leg 62 arranged so as to extend from the column 2 to below the top plate 5. The column support member 61 is formed by an oval crushed pipe and can be used as it is in contact with the floor surface. In the present embodiment, the ball casters 63 made of rubber, plastic, or the like are provided on the back sides of both ends. , 63 are provided so that they can move freely. Note that both open ends of the column support member 61 are closed by lid members 64, 64. A caster 65 is provided at the tip of the auxiliary leg 62 as shown in FIGS.

The strut 2 is used to prevent the top plates 4 and 5 from turning.
At least an inner cylinder having a non-circular outer peripheral surface, such as a pipe having a polygonal cross section such as a square pipe or a hexagonal pipe, a D-cut pipe (a pipe having a D-shaped contour), an elliptic pipe, or the like is used. In the case of the present embodiment, what is called a square pipe is adopted as the inner cylinder from the viewpoint of ease of processing and availability, and a cylindrical pipe is used for the lower support 21 serving as the outer cylinder, and the upper support is used. The support column 2 is configured as a double cylinder in which the lower tube 22 fits in and out of the lower support column 21 freely. In order to prevent rotation between the lower support 21 and the upper support 22, a lower open end 2 of the upper support 22 is used.
Resin sliding bearings 23 and 24 having square holes are fitted in the opening end 21a of the lower support 21 and the lower support 21. The upper end of the upper support 22 as the inner cylinder and the lower support 2 as the outer cylinder
The column 2 is provided so as to expand and contract by expansion and contraction of a gas spring 15 disposed between the lower end of the support 1 and the gas spring 15. In order to prevent the rotation of the column 2, it is not necessary to use a square pipe or the like. For example, a vertical key groove is formed on the inner peripheral surface of the lower column 21, and a sliding key that fits into the vertical key groove is placed on the upper side. Rotation can also be prevented by providing it on the outer peripheral surface of the column 22.

The sliding bearing 23 comprises a cylindrical portion 23a fitted in the upper column 22 and a flange 23b abutting on the end face of the upper column 22. As shown in FIG. The flange 23b is formed in a square shape in accordance with the shape and size of the inner peripheral surface of the lower support 21 while being formed in a square shape in accordance with the support 22. A round hole 23c is formed in the center of the sliding bearing 23 so that the gas spring 15 installed in the upper support 22 can be penetrated.

The sliding bearing 24 is also formed in a round shape with a cylindrical portion 24a fitted into the upper support 22 and a flange 24b abutting on the end surface of the upper support 22, so that the upper support 22 is slid in the center. Bearing surface 24c for
Is provided. These slide bearings 23 and 24 are fixed to the respective columns 21 and 22 by a screw 25 so as not to rotate. As a result, the upper corner support 22 is provided so as to be able to move up and down in the lower support 21 while the lower end thereof is supported by the slide bearing 23, and the middle part of the upper support 22 is supported by the slide bearing 24. Further, since the slide bearing 24 is non-rotatably attached to the lower support 21 by the screw 25, the upper support 22 always keeps the rotation center axis 3 in one direction without rotating. These slide bearings 23 and 24 are injection-molded with a general resin bearing material, but are not particularly limited thereto, and may be formed of a sintered oil-impregnated bearing material or a general metal bearing material.

As shown in FIGS. 1 and 3, a rotation center shaft support plate 11 is provided at the upper end of the upper support 22, and the rotation center shaft 3 is mounted on the support plate 11. As shown in FIG. 1, the rotation center shaft supporting plate 11 is formed by bending a plate material into an L shape, and a substantially semicircular notch 11a is formed in the bent portion to support the rotation center shaft 3. A U-shaped cover 12 that covers the side is provided on the upper part of the rotation center shaft support plate 11.

The rotation center shaft 3 is a rod-shaped member that supports the movable top plate 5, and has a circular outer periphery. In this embodiment, a round pipe is used to reduce the weight. The end of the rotation center shaft 3 near the support 2 is crushed by press working or the like to form a flat plate-like mounting portion 3a as shown in FIGS. 1 and 3, and is mounted on the rotation center shaft support plate 11 or the like. It is structured to facilitate the operation.

A fastening means 10 for pressing the top plate 5 against the top plate 4 serving as a fixing member is provided on the tip end end 3b side of the rotation center shaft 3. In this embodiment, a screw pair consisting of a female screw member 7a and a male screw member 7b is employed as the fastening means 10. The female screw member 7b is fixed to the open end 3b on the free end side of the rotation center shaft 3 by welding or the like, and the male screw member 7b is screwed into the female screw member 7b. The bearing 73 of the top plate 5 is fixed to the grip 7c of the male screw member 7b. It is provided so as to be pushed in the axial direction.

On the other hand, a cylindrical member fixing plate 13 is attached to the lower part of the rotation center shaft support plate 11 as necessary.
Is fixed to the cylindrical member 14. In this case, the rotation center shaft support plate 11 is provided with two round holes 11b, 11b as shown in FIG. 1, and the cylindrical member fixing plate 13 has two round holes 11b, 11b engaged with the round holes 11b, 11b. It is fixed by the engagement projections 13a, 13a. The fixing plate 13 has a boss 13 protruding downward.
The cylindrical member 14 is integrally formed, and the cylindrical member 14 is fitted into the boss 13b, and is fixed by screwing.
As shown in FIG. 3, the cylindrical member 14 has an inner diameter larger than the outer shape of the lower support 21, and at least a lower end thereof always overlaps an upper end of the lower support 21. In other words, the cylindrical member 14 provided in this manner covers the upper support 22 so as not to be visible from the outside even if it moves up and down, and functions as a blindfold of the upper support 22. The cylindrical member fixing plate 1
3 is provided with a slide bearing surface 13c through which the upper column 22 can pass, as in the other members.

The gas springs 15 are arranged so that the height of the upper part from the upper support 22 is determined.
Is installed in the lower support 21 and the upper support 22 so that the height of the support can be arbitrarily adjusted as shown in FIG. The gas spring 15 used in the present embodiment is a publicly known general one, and a gas spring having no particular feature is not employed, so that a detailed description of itself is omitted here. This gas spring 15 is shown in FIG.
As shown in FIG. 2, the lower end is attached to the support member 61 by an E-ring 16 and the upper end is attached to the attachment portion 3a by a nut 17 as shown in FIG. A valve (not shown), which is a vent of the gas spring 15, is provided so as to be opened and closed by the leverage of the telescopic handle 18. The telescopic handle 18 is arranged so as to engage with the groove 12a of the U-shaped cover 12 and is swingable in the vertical direction. The spring 15 can expand and contract in the vertical direction.

3 and 6 above the rotation center axis 3.
The top plates 4 and 5 of the table 1 are attached as shown in FIG. The top plates 4 and 5 are composed of a non-rotatable fixed top plate (fixing member) 4 and a movable top plate 5 rotatable around the rotation center axis 3 and slidable in the axial direction. I have. In this embodiment, as shown in FIG. 6, the movable range is increased by increasing the ratio of the area of the movable top 5 to the entire top, and the movable range is increased.
Is fixed, a fixed top plate 4 and a single top plate are configured.

The fixed top plate 4 is provided with a rotation center shaft support plate 11 and a U-shaped cover 12 provided horizontally above the column 2.
It is fixed to such. On the other hand, the movable top plate 5 is provided with two bearings 72, 73 as shown in FIGS. 1 and 6 on the back side thereof, and the rotation center shaft 3 is provided via these bearings 72, 73.
Is mounted so as to be rotatable and slidable. in this case,
The bearings 72 and 73 are fixed to the back surface of the movable top plate 5 and function as support members for supporting the movable top plate 5. In the present embodiment, the movable top plate 5 is allowed to tilt as described below. Or the function of regulating.

That is, in addition to the two bearings 72 and 73 on the back side of the movable top plate 5, the bearing 71 is also mounted on the back side of the fixed top plate 4. Of these three bearings 71 to 73, the fixed top plate is mounted. The bearing 71 on the fourth side and the bearing 72 on the movable top plate next to the bearing 71 are provided with engaging members 8,
The movement of the movable top plate 5 is restricted by providing the movable top plate 9.

In this case, one meshing member, for example, a meshing member indicated by reference numeral 9 on the movable top plate 5 side (hereinafter referred to as a movable meshing member 9) is formed as shown in FIGS. . That is, the movable meshing member 9 is provided at the tip end of the boss portion 72a that protrudes greatly from the bearing 72 toward the bearing 71, and the meshing member on the fixed top plate 4 side, which is the other meshing member (in this specification, 8 (referred to as a fixed meshing member). The movable meshing member 9 may form irregularities, for example, mountain-shaped teeth over the entire circumference, but it is sufficient that at least a necessary portion is formed in a limited range. Further, in the present embodiment, from the viewpoint of restricting the rotatable range of the movable top plate 5, not all of the circumference as shown in FIG. ) Is provided with a protruding boss portion 72a, and the teeth 9a are provided only at the tip of this protruding portion. Therefore, the remaining portion (that is, the portion corresponding to the central angle of about 270 ° where the teeth 9a are not provided) is flat without protruding in the axial direction. On both sides of the bearing 72, bolt holes 72 for fixing the bearing 72 to the back side of the movable top plate 5 are provided.
c and 72c are provided so that they can be fixed with two bolts.

On the other hand, the shape of the fixed meshing member 8 is shown in FIGS.
As shown in FIG. 12, the teeth 8 a meshing with the chevron teeth 9 a of the movable meshing member 9 are formed, and are formed in a concave shape in a predetermined range so as to limit the movable range of the movable meshing member 9. . That is, as shown in FIG. 12, not the entire circumference but a partial area (for example, as shown in FIG. 11, a central angle of 180 °
A concave portion 71a is formed in a portion corresponding to a weak arc),
The teeth 8a are formed only in the concave portions 71a. In this case, the concave portion 71a is made larger than the movable meshing member 9, and is formed so that a part of the boss portion 72a can move in the concave portion 71a. In the present embodiment, the concave portion 71a is 180 °
Since the boss portion 72a is a weak circular arc of about 90 °, the boss portion 72a can swing left and right by the difference, that is, less than 90 °, and hits the wall of the concave portion 71a at its swing end. The swing range is regulated. That is, the wall of the concave portion 71a in this case functions as the stopper 71b that limits the movable range of the boss portion 72a. Note that the numerical values of the center angles of the boss portion 72a and the concave portion 71a described above are merely examples, and can be appropriately changed within a range where a desired swing width of the movable top plate 5 can be obtained. However, the boss portion 72a is preferably formed with a certain width in order to secure strength when the boss portion 72a hits the wall 71b of the concave portion 71a.

The bearing 71 is also provided with screw through holes 71c, 71c for fixing to the back side of the fixed top plate 4. And the bearing 7 provided with such a meshing member 8
1 is fixed to the back side of the fixed top plate 4, and the bearing 72 provided with the meshing member 9 and the simple bearing 73 are fixed to the back side of the movable top plate 5 so as to be coaxially arranged.

Further, in the present embodiment, between the bearing 72 having the movable meshing member 9 and the bearing 71 having the fixed meshing member 8, there is provided a biasing means 1 such as a coil spring.
9 are provided so that the meshing members 8 and 9 can be easily separated from each other. As shown in FIGS. 9 and 13, the urging means 19 includes stepped portions 71e and 72 formed between the through hole 71d and the meshing member 8, and between the through hole 72b and the meshing member 9, respectively.
Although provided using d, this is merely an example, and may be provided around the bearings 71 and 72, for example, or a plate spring may be used instead of the coil spring. As a result of the biasing of the engagement members in the direction in which they are separated from each other, the movable top plate 5 automatically separates from the fixed top plate 4 when the fastening means 10 is loosened, and the axial direction generated by the sliding width. You will be able to eliminate play and play.

According to the table 1 using the telescopic device with a rotation preventing mechanism configured as described above as a support, the top plates 4 and 5 attached to the upper end of the support 2 are supported so as to be able to move up and down freely without turning. Is done. Moreover, a square pipe is used as the upper support 22 of the telescopic device, and this is used as the lower support 21.
Since the gasket 15 is provided so as to be non-rotatable only with the plain bearing 24, the gasket 15 cannot be rotated even if the gas spring 15 is used alone. The upper part, including it, does not rotate. When a telescopic device configured using a simple member such as a non-circular pipe and a plain bearing is employed for a cantilevered table 1 as in the present embodiment, a low-cost member can be used and relatively simple. With such a configuration, it is possible to prevent the top plates 4, 5 and the like from rotating around the vertical axis.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, a case has been described in which the telescopic device with the rotation preventing mechanism is applied to the cantilever typing table 1, but the present invention is not limited to such a table and can be widely applied to other telescopic devices. That is, the telescopic device of the present invention in the above-described embodiment substantially functioned as an elevating device for elevating and lowering the table, but in addition to being provided in the vertical direction as described above, even when provided in an oblique or horizontal direction, It goes without saying that each can function as a telescopic device with a rotation preventing mechanism.

In this embodiment, the case where the lower support 21 of the telescopic device is formed as an outer member and the upper support 22 is formed as an inner member made of a square pipe is described. However, the present invention is not particularly limited thereto. It is also possible to use the square pipe as the lower column 21 and as the outer member / upper column 22 of the round pipe which expands and contracts while sliding around the lower column 21.

Further, in the present embodiment, the slide bearing 24 is mounted so as not to be rotatable with respect to the lower support 21. However, as means for slidably supporting the upper support 22, the other members are integrally formed as described above. The sliding bearing may be integrally formed by plastic working such as drawing at the end of the lower support 21, for example.

In the present embodiment, the bearing surface 24c of the slide bearing 24 is formed in a shape corresponding to the shape and size of the outer peripheral surface of the upper support 22, but this shape is substantially equal to the outer peripheral shape. In addition to the above case, a structure in which a part of each surface slides as shown in FIG. 14A, or a structure in which a corner part slides as shown in FIG. 14B may be used. Also in the case described above, the upper support 22 does not rotate with respect to the lower support 21 and does not move laterally from the central axis.

As the polygonal member, a quadrangular prism called a so-called square pipe is the most common and is preferably used because it is easily available at a low cost. However, it is also preferable to use a prism having a triangular or pentagonal shape. As described above, pipes can be used, and the polygonal member in this case can be a so-called regular polygonal shape or not. To put it extreme,
From the viewpoint of preventing the rotation of the top plates 4 and 5, the upper support 22 need not be round, and may be, for example, a semicircle or a star if the processing cost is not considered. good.

[0035]

As is apparent from the above description, according to the expansion and contraction device with the rotation preventing mechanism according to the first aspect, at least one fitting member between the non-circular member such as the square pipe and the outer member. With a simple structure with two sliding bearings, it is possible to slide without rotating. Therefore, even if a specially shaped gas spring is not used, the rotation preventing function of the telescopic device can be realized by using a generally easily available low-cost round gas spring.

Further, according to the expansion and contraction device with a rotation preventing mechanism according to the second aspect, when the inner member slides, it is unlikely that the outer member is axially displaced, so that the expansion and contraction can be performed while the center axes of the inner member are aligned.

According to the telescopic device with a rotation preventing mechanism according to the third aspect, the rotation of the inner member can be prevented by using an inexpensive pipe that can be formed relatively easily than pipes of other shapes. A telescopic device with a rotation preventing mechanism can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a table showing an embodiment of a telescopic device with a rotation preventing mechanism according to the present invention.

FIG. 2 is a longitudinal sectional view showing a configuration of a cylindrical member and a leg of a table.

FIG. 3 is a longitudinal sectional view showing a configuration of an upper portion of a column of the table and a portion above the column.

FIG. 4 is a side view of the table as viewed from the column side, showing how the top plate moves up and down.

FIG. 5 is a partial side view showing a state in which a top plate rotates around a horizontal axis to change its inclination.

FIG. 6 is a plan view of a partly broken table.

FIG. 7 is a plan view showing a bearing and a movable gear attached to a movable top plate.

FIG. 8 is a diagram showing a bearing and a movable gear attached to the movable top plate, as viewed in the axial direction from the fixed top plate side.

9 is a cross-sectional view of the bearing and the movable gear shown in FIG. 8 taken along line IX-IX.

FIG. 10 is a plan view showing a bearing and a fixed gear attached to a fixed top plate.

11 is a view of the bearing and the fixed gear shown in FIG. 10 as viewed from the movable top plate side in the axial direction.

FIG. 12 is a cross-sectional view of the bearing and the movable gear shown in FIG.
It is sectional drawing in a line.

FIG. 13 is a diagram showing the shape of the teeth of the movable gear in detail;
(A) is a partial enlarged view of the lower side in FIG. 8, and (B) is a bottom view of the movable gear shown in (A).

FIG. 14 is a diagram illustrating an example in which a part of a cylindrical member is formed according to the shape and size of the outer peripheral surface of a polygonal member;
(A) is a case in which a part of each surface is slidably contacted, (B)
Indicates a case in which it is slid on the corner.

[Explanation of symbols]

 15 Gas Spring 21 Lower Support (Outer Member) 22 Upper Support (Inner Member) 24 Slide Bearing 24c Bearing Surface of Slide Bearing

Claims (3)

[Claims] 1. A telescopic device comprising: a support member formed of at least a double cylinder which is telescopically fitted; and a gas spring built in the support member to expand and contract the support member. The member is formed of a member having a non-circular cross-sectional profile, has a sliding bearing surface having the same shape as the cross-sectional profile of the inner member, and is fixed to an outer member of the support member. At least one sliding bearing that slidably supports the sliding member, wherein the inner member slides non-rotatably relative to the outer member while slidingly contacting the inner peripheral surface of the sliding bearing. Telescopic device with anti-rotation mechanism. 2. A sliding bearing which is in sliding contact with the inner peripheral surface of the outer member and is supported by the inner member is disposed at an end of the inner member which is always occupied in the outer member. An end of the outer member that enters and exits has a slide bearing surface having the same shape as the cross-sectional profile of the inner member, and is fixed to the outer member of the support members to slidably support the inner member. The expansion / contraction device with a rotation preventing mechanism according to claim 1, wherein a slide bearing is disposed, and the inner member and the outer member are supported at at least two places. 3. The telescopic device according to claim 1, wherein the inner member is a square pipe.