Supports – Stand – Standard type
Reexamination Certificate
2000-06-12
2001-11-13
Ramirez, Ramon O. (Department: 3632)
Supports
Stand
Standard type
C248S162100, C248S188200
Reexamination Certificate
active
06315262
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to an auto-returning height-control assembly for a chair wherein a chair returns to its original place automatically when a person stands up from a chair or sits down on a chair and turns the chair.
2. Description of the Background Invention
FIG. 1
is a vertical cross sectional view which shows a conventional height adjusting assembly for a chair. The conventional height adjusting assembly comprises a outer cylinder
600
, a spindle guide
500
which is inserted and fixed inside the outer cylinder
600
and a spindle
150
which slides along the inside surface of the spindle guide
500
.
The spindle
150
is connected with a piston rod
110
and extends outwards toward the outer cylinder. The height of the spindle is adjustable along the axis of the piston rod and a push button (
133
), which is put on and off to make the spindle move up and down along the axis of the piston rod, is installed at an outer end of the spindle. An end of the piston rod
110
is fixed to the outer cylinder
600
with a fixing clip
235
. An elastic member
620
for absorbing the shock which is put on the outer cylinder
600
by the lower end of the spindle
150
when spindle
150
moves up and down along the axis of the piston rod is inserted at the lower end of the piston rod
110
. A thrust bearing
142
is inserted at the lower end of the shock absorbing cushion member
620
. A movement preventing projection
135
is formed a the lower end of the piston rod
110
in order to prevent the thrust bearing
142
from moving upwards. As the shock absorbing cushion member
620
and the thrust bearing
142
are inserted at the piston rod
110
, the shock put on the spindle
160
is absorbed and the rotation static-electricity is reduced. A push button
133
is formed at an outer end of the spindle
150
and the spindle is allowed to rotate and move up and down along the inside of the spindle guide
500
according to the operation of the push button in the conventional auto-returning height control assembly. In the conventional art, the push button used in adjusting the height of a chair is formed at an end of the spindle
150
and an operation lever
188
located at the lower end of the chair is used to push the push button
133
as shown in FIG.
2
.
As the conventional auto-returning height control assembly is structured to control the rotation of the spindle
150
inside the spindle guide
500
, the seat
121
of a chair does not return to its original place after a person has used the chair and made it rotate in a certain degree. In order to make the seat of a chair return to its place, an artificial force has to be put on and rotate the seat. Therefore, there is inconvenience in arranging seats of chairs into their original places after using them, and especially, when there are larger number of chairs, it is time and manpower consuming to do all the chairs.
The present invention is to overcome the problems of the convention art by providing an auto-return height control assembly in which the seat of a chair returns to its place automatically after using the chair.
SUMMARY OF THE INVENTION
The present invention is conceived to solve the problem of the conventional height adjusting assembly and to provide a height adjusting assembly for chairs comprising a spindle which is projected outwards and is adjustable, a sleeve member which covers the outside of the spindle and in which more than one groove is formed along the direction of the axis at the outside of the spindle, a first cam member which allows the sleeve member to rotate about the longitudinal axis of the spindle, a second cam member which has projections inside and the projections are inserted into the groove of the sleeve member and moves up and down along the direction of the axis of the spindle against the sleeve member and rotates simultaneously along the rotation of the sleeve member, and an elastic member which pushes the second cam member to make the slope side of the second cam member to face the slope side of the first cam member.
The first cam member comprises a first cylindrical part and a second cylindrical part which has different diameter and is structures so that the second cam member can be inserted inside the second cylindrical part. One end of the elastic member is combined to the second cam member and the other end is limited in its movement along the length direction by the outer cylinder and if the rotation force of the sleeve member is eliminated, the elastic member returns to its place and pushes up the second cam member so that the slope side of the first and second cam member face each other and therefore, the sleeve member is rotated to its original place.
A projection is formed at a certain location of the outer cylinder and a washer is inserted between the projection and the elastic member in order to limit the moving direction of the elastic member. A ring in which more than one penetration hole is formed and a thrust bearing are installed between the elastic member and the second cam member and a spacer of a taper form which is fixed with the outer cylinder is installed at the lower part of the elastic member. The spacer, sleeve member, ring and the washer can be made of aluminum alloy, metal, metalloid and resin.
REFERENCES:
patent: 1895226 (1933-01-01), Kupski
patent: 2351194 (1944-06-01), Davies
patent: 3385550 (1968-05-01), Doerner
patent: 3837611 (1974-09-01), Rhoades
patent: 5269398 (1993-12-01), Wolf et al.
patent: 332426-B1 (1958-10-01), None
patent: 134205-B1 (1920-06-01), None
Ramirez Ramon O.
Samhongsa Co. Ltd.
Szumny Jon
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