JPH0646937A - Leg device for chair - Google Patents

Abstract

PURPOSE:To prevent a tubular support of a leg of a chair, where a bushing is fitted in the tubular support of a leg post to prevent the leg post from tilting, from being reduced in strength by press-fitting the bushing into the tubular support, and to keep the bushing from slipping off by simply press-fitting it into the tubular support. CONSTITUTION:A bushing 9 is either divided into two or shaped into a C shape, so that it can be deformed inward in the radial direction. And, the bushing 9 is press-inserted into a tubular support 5a against its elasticity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved leg device for a chair.

[0002]

2. Description of the Related Art In general, a chair leg device is provided with a cylindrical support portion having an upward opening at the center of a leg body provided with a plurality of leg rods extending radially in a plan view, while a bottom surface of a seat body is provided. From this, a pedestal such as a gas spring is projected downward, and this pedestal is configured to be supported by the tubular support portion.When a gas spring is used as the pedestal, generally, the gas spring is The piston rod is arranged so as to face downward, and while the lower end of the piston rod is locked to the tubular support portion, the upper end of the cylinder is fixed to the lower surface of the seat body to move the cylinder up and down. There is.

In this case, in order to hold the cylinder of the gas spring in a state in which it cannot fall down, for example, Japanese Patent Laid-Open No. 60-60813.
As described in Japanese Patent Publication, at the upper end of the tubular support,
A bush body made of synthetic resin to be fitted to the cylinder of the gas spring is fitted, and the bush body guides the vertical movement of the cylinder in the gas spring.

As a means for fitting the bush body to the tubular support portion, conventionally, the bush body is formed in a tubular shape, and the outer peripheral surface of the bush body and the inner peripheral surface of the tubular support portion are formed. The bush body is press-fitted into the tubular support portion from above by forming a tapered surface with a radius decreasing toward the lower end.

[0005]

[Problems to be Solved by the Invention] However, in this way,
In the configuration where the bush body is simply formed into a tubular shape,
Since the bush body does not deform so as to shrink inward in the radius, the bush body is pressed in too much and the tubular support part is cracked or the tubular support part is easily damaged. However, there is a problem that the strength of the tubular support portion is reduced.

Further, since the fitting of the bush body to the tubular support portion is likely to be loosened due to vibration or the like while the chair is continuously used, in order to prevent the bush body from being loosened to the tubular support portion, The bushing body and the tubular support portion are configured such that the retaining pin penetrates the radial direction in the radial direction, which causes a problem that it takes time to assemble the leg device.

An object of the present invention is to provide a leg device which solves these problems.

[0008]

In order to achieve this object, the present invention provides a leg which is in contact with a floor with a tubular support portion into which a pedestal for a seat is fitted from above, and the tubular support portion is provided. In a chair formed by fitting a bush body fitted to the pedestal, the bush body is formed in a split shape or a substantially C-shape in plan view so that the radius can be reduced against elasticity. Then, the bush body is configured to be press-fitted into the tubular support portion from above.

[0009]

With this structure, the bush body can be deformed radially inward against its elasticity, so that the pressing force acting radially outward is excessively applied to the cylindrical support portion. It is possible to press-fit the bush body into the tubular support portion and fit it tightly without doing so.
It is possible to prevent the strength of the tubular support portion from being reduced due to the press-fitting of the bush body.

Further, while the bush body is fitted in the tubular support portion, the elastic restoring force of the bush body acts on the bush body as a pressing force outward in the radial direction. Even if vibration or the like acts on the leg device, the bush body is hardly loosely fitted in the tubular support portion. Therefore, the tubular support portion and the bush body are prevented from coming off by the retaining pin as in the conventional case. There is no need for locking, and as a result the leg device assembly process can be simplified.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. 1 to 6 show a first embodiment, and in these drawings, a chair designated by reference numeral 1 is composed of a seat body 2, a backrest 3 and a leg device 4, and the leg device 4 is directed upward. A leg body 5 is formed by radially extending a plurality of leg rods 5b from an open cylindrical support portion 5a, and a gas spring 6 as an example of a pillar. A caster 7 is provided at the tip of each leg rod 5b of the leg 5 so as to be in contact with the floor.

The gas spring 6 is provided with a cylinder 6a and a piston rod 6b fitted therein, and the upper end of the cylinder 6a is fixed to the lower surface of the seat body 2 so that the cylinder 6a
The lock between the cylinder 6a and the piston rod 6b is released by pressing the operation rod 8 protruding from the upper end surface of a with a lever (not shown) or the like.

A bottom plate 5c is provided on the tubular support portion 5a of the leg body 5, and a bush body 9 is provided on the tubular support portion 5a for guiding the cylinder 6a of the gas spring 6 so as to be vertically movable in a state in which it cannot be tilted. In fitting, the bush body 9 is formed in a split shape, and the outer peripheral surface of the bush body 9 and the inner peripheral surface of the tubular support portion 5a are formed in a loose taper shape whose diameter decreases toward the lower end. The bush 9 is pressed into the tubular support 5a from above against its elasticity.

A guide portion 9a is formed on the upper portion of the bush body 9 so as to be in sliding contact with the cylinder 6a of the gas spring 6, while a positioning hole 9b is formed in the lower portion of the bush body 9 so that the lower end of the piston rod 5b can pass through. Then, the load is supported by the bottom plate 5c of the tubular support portion 5a. Further, the positioning hole 9b of the bush body 9 is provided with an annular engagement groove 9c into which the retaining ring 10 engaged with the lower end of the piston rod 6b of the gas spring 6 is fitted.

As shown by the chain double-dashed line in FIG. 5, the outward exposed portion of the gas spring 9 is covered with a stretchable cover body 11. In the above configuration, as shown in FIG. 1, the split bush body 9 is superposed so as to hold the gas spring 9, and in that state, the bush body 9 is attached to the tubular support portion 5a of the leg body 5. The leg device 4 can be assembled by press-fitting from above.

In this case, since the bush body 9 is divided into two halves, the bush body 9 can be elastically deformed radially inward, so that the tubular support 5 is excessively outwardly radiated. The bush body 9 can be fitted tightly into the tubular support portion 5a without pressing, and
It is also possible to prevent the bush body 9 from being loosely fitted in the tubular support portion 5a.

The retaining ring 1 is provided without contacting the lower end surface of the piston rod 6b with the bottom plate 5c of the cylindrical supporting portion 5a.
The load may be supported by 0, and by doing so, the load supporting area of the bottom plate 5c in the tubular supporting portion 5a can be increased, and the load on the bottom plate 5c can be reduced. In this case, as shown by the alternate long and short dash line in FIG. 5, the lower end of the piston rod 6b is penetrated downward from the bottom plate 5c of the cylindrical support portion 5a, and this is locked by the retaining washer 12 or the split pin. May be.

FIG. 7 to FIG. 9 show a second embodiment. In this embodiment, the support 13 provided at the lower end of the piston rod 6b of the gas spring 6 is attached to the cylindrical support portion 5.
When it is supported by the bottom plate 5c of a, the tubular support portion 5a of the leg 5 is formed so as to extend high upward, and the upper end portion of the tubular support portion 5a is formed into a generally C-shape in plan view. The bush body 9 with 9d is press-fitted from above against its elasticity, and the bush body 9 guides the vertical movement of the cylinder 6a in the gas spring 6.

Also in this embodiment, since the bush body 9 is fitted to the tubular support portion 5a against the elasticity thereof, the tubular support portion 5 is
The bush body 9 can be fitted to the tubular support portion 5a without excessively exerting a pressing force outwardly on the a, and the bush body 9 is loosely fitted to the tubular support portion 5a. Can be prevented. In the second embodiment, the bottom plate 5c of the tubular support portion 5a is integrally formed with the reinforcing member 14 formed in a mat shape with a wire net, carbon fiber, non-woven fabric, pulp or the like. 6
The lower end of b is penetrated from the bottom plate 5c of the tubular support portion 5a, and this is locked by the washer 12 which prevents it from coming off.

As described above, when the reinforcing member 14 is integrally formed with the bottom plate 5c of the tubular support portion 5a, the strength of the bottom plate 5c can be improved without increasing the thickness of the bottom plate 5c. In the present invention, the leg is not limited to the synthetic resin and may be made of metal. Further, as described in the above-mentioned prior art, the metal pipe is fitted into the support hole in the synthetic resin leg. This can also be applied to a case where the tubular support portion is formed and the bush body is press-fitted into the tubular support portion made of a metal pipe.

As in the first embodiment, the length of the bush body 9 is increased to form the guide portion 9a for the gas spring 6 on the upper portion of the bush body 9, or the second embodiment is used. As in the example, the cylindrical support portion 5a extending upwardly is formed by integral molding on the leg 5 made of synthetic resin, and the upper end of the cylindrical support portion 5a formed by this integral molding is formed. When the bush body 9 is fitted to the above, it is not necessary to separately provide a metal pipe for forming the cylindrical support portion as in the above-mentioned prior art, so that the structure of the leg device can be simplified. Have advantages.

[Brief description of drawings]

FIG. 1 is an exploded view of a main part of a first embodiment.

FIG. 2 is a perspective view of a chair.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a bottom view of the leg.

5 is a cross-sectional view taken along line VV of FIG.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 shows a second embodiment, (A) is a vertical sectional front view,
(B) is a BB sectional view of (A), and (C) is a plan view of the bush body.

8 is an enlarged cross-sectional view of the bottom plate of the tubular support portion in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chair 2 Seat body 4 Leg device 5 Leg body 5a Cylindrical support part 6 Gas spring as an example of a pedestal 9 Bush body

Claims (1)

[Claims] 1. A leg support grounding on a floor surface is provided with a tubular support part into which a pedestal supporting a seat is fitted from above, and a bush body fitted into the pedestal is fitted to the tubular support part. In a fitted chair, the bush body is formed in a halved shape or a substantially C-shape in a plan view so that it can be deformed radially inwardly against elasticity, and the bush body is formed into the tubular shape. A leg device in a chair, which is press-fitted into a supporting portion from above.