Chairs and seats – Movable bottom – Bottom and back movable as a unit
Reexamination Certificate
1998-11-17
2001-06-05
Cranmer, Laurie K. (Department: 3624)
Chairs and seats
Movable bottom
Bottom and back movable as a unit
C297SDIG003, C277S440000, C267S064120, C248S161000, C248S631000
Reexamination Certificate
active
06241316
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for adjusting the height of a swivel chair, and more particularly to a gas cylinder type height-adjusting apparatus of a swivel chair which has a simple structure and thereby can be manufactured at a low cost.
2. Description of Prior Art
In general, a swivel chair has a part named as a spindle which performs functions of not only supporting the weight of a person seated thereon but also adjusting the height of the chair according to the physique of the person.
The spindle is an important part of a swivel chair in adjusting the height of the chair and can be classified as two types according to the height-adjusting manner, including a screw-adjusting type using a screw spindle and a gas cylinder type in which usually a nitrogen gas functions as a working fluid.
FIG. 1
is a sectional view of a conventional height-adjusting apparatus of a swivel chair having a gas cylinder type spindle for showing the construction thereof. In
FIG. 1
, reference numeral
10
designates a spindle having a shape of a cylinder. The spindle
10
is inserted in an outer tube
20
having a larger diameter, and a piston rod
30
is inserted into the spindle
10
through the bottom of the spindle
10
.
A top stopper
16
is fixed to the top of the spindle
10
, and an actuating protuberance
14
is slidably fitted in the top stopper
16
. The actuating protuberance
14
is connected to a height-adjusting lever (not shown) for adjusting the height of the swivel chair. A pushing rod
18
integrally formed under the actuating protuberance
14
is in contact with an actuating pin
19
. The actuating pin
19
is slidably fitted in an actuating pin socket
40
so as to slide up and down therein. The actuating pin socket
40
, whose more detailed construction will be given later, is fixed in the spindle
10
with providing gas-tight therein.
The outer tube
20
of a cylindrical shape has a spindle support
50
fixed to a lower part of the outer tube
20
. The piston rod
30
is fixed to the spindle support
50
. The spindle
10
has a spindle neck
12
at an upper part thereof which is tapered so as to be inserted in a seat (not shown) of the chair.
The spindle
10
surrounds a cylinder
44
which has a smaller diameter than the spindle
10
. The spindle
10
has a buffer disposed in the spindle
10
for providing a comfortable feeling for the person seated thereon. A thrust bearing
60
is arranged on the spindle support
50
so as to ensure a smooth swivel of the chair with bearing the weight from above. The reference numeral
62
designates a cushion such as a rubber which comes into contact with the bottom of the spindle
10
. The cushion
62
buffers the impact on the bottom of the spindle
10
when the spindle
10
is lowered down to its lowermost position.
The bottom of the piston rod
30
is detachably installed on the spindle support
50
by means of a clip
70
. In
FIG. 1
, the reference numeral
52
designates a spindle holding member which is disposed between the spindle
10
and the outer tube
20
so as to hold the spindle
10
in such a manner that the spindle
10
can slide therethrough into and out of the outer tube
20
.
FIG. 2
is an enlarged sectional view of the actuating pin socket
40
disposed in the spindle
10
of FIG.
1
. As shown, the actuating pin socket
40
, shaped roughly like a cylinder, has an actuating pin hole
41
formed through the center of the actuating pin socket
40
in which the actuating pin
19
is fitted. The actuating pin socket
40
also has a plurality of socket O-ring grooves
43
formed around the outer circumferential surface of the actuating pin socket
40
in each of which a socket O-ring
45
is fitted.
The inner center portion of the actuating pin socket
40
forms a central space
46
for passing gas therethrough in which at least two socket O-rings
45
and an inner holder
47
are arranged. The socket O-rings
45
maintain gas-tight in the central space
46
, and the inner holder
47
holds the socket O-ring
45
of the inner side and helps smooth sliding of the actuating pin
19
. The actuating pin socket
40
has an orifice
42
formed at one side of the actuating pin socket
40
. The orifice
42
is connected to an outer space of the cylinder
44
. The inner holder
47
has a connecting pore
47
a
formed at one side of the inner holder
47
and connected to the orifice
42
.
Referring to
FIG. 2
, the actuating pin
19
has a small-diameter portion
19
a
formed at a middle portion of the actuating pin
19
. The small-diameter portion
19
a
has a diameter smaller than that of the remaining portion of the actuating pin
19
. When the actuating pin
19
is lowered down, the small-diameter portion
19
a
makes a small gap between the actuating pin
19
and the actuating pin socket
40
, so that gas filled in a first chamber A can flow into the central space
46
of the actuating pin socket
40
and then into a second chamber B through the orifice
42
. In
FIG. 2
, reference numeral
13
designates a holding washer provided in the actuating pin socket
40
to hold the socket O-rings
45
in the actuating pin socket
40
. Nitrogen gas and oil are filled in the first chamber A, as working gas and fluid.
FIG. 3
is an enlarged sectional view for showing the construction of a piston
80
installed at the top of the piston rod
30
in detail, and
FIG. 4
is an enlarged sectional view for showing the operation of the piston
80
.
The piston rod
30
has a piston rod head
87
which prevents the piston rod
30
from being separated from the piston
80
. The piston
80
has a plurality of inner and outer O-ring grooves in each of which a piston O-ring
82
is fitted to make gas-tight. The piston
80
has various parts which enable the piston
80
to smoothly and closely slide in the cylinder
44
and prevent the piston
80
from coming out of the spindle
10
. The bottom of the spindle
10
is bent inward so as to prevent the piston
80
from escaping.
The spindle
10
houses a flange
83
disposed in the bottom thereof and a sealing member
84
disposed on the flange
83
for maintaining gas-tight in the cylinder
44
. Between the piston
80
and the sealing member
84
, an annulus
85
and a cylinder holder
86
are arranged in order from above. The annulus
85
surrounds a spring ring
88
for fixing the piston
80
to the piston rod
30
, and the cylinder holder
86
supports the bottom of the cylinder
44
.
Referring to
FIG. 4
, the cylinder holder
86
has a gas-passing hole
86
a
formed through an outer portion of the cylinder holder
86
. The gas-passing hole
86
a
provides a path from the second chamber B to the third chamber C. Therefore, the gas-passing hole
86
a
enables the gas to flow from the first chamber A through the second chamber B into the third chamber C. Arrows in
FIG. 4
shows the gas flow from the second chamber B to the third chamber C.
FIGS. 5A and 5B
are respectively an exploded and an assembled elevations of the actuating pin
19
employed in the conventional gas cylinder type height-adjusting apparatus shown in FIG.
1
. The actuating pin
19
has a small-diameter portion
19
a
and two large-diameter portions
19
b
. The small-diameter portion
19
a
is integrally connected to each of the large-diameter portions
19
b
through a sloping portion
19
c
. The lower large-diameter portion
19
b
has an actuating pin neck
19
d
protruding downward from the bottom of the large-diameter portion
19
b.
Referring to
FIG. 5B
, the actuating pin neck
19
d
is inserted in a fixing washer
17
and then a holding head
19
e
is assembled at the lower end of the actuating pin neck
19
d
, so as to fix the fixing washer
17
thereto. The fixing washer
17
comes apart from the holding washer
13
when an external force as shown by an arrow in
FIG. 2
is applied, while the fixing washer
17
comes into contact with the holding washer
13
when the pressure of the gas filled in the first chamber A is applied to the fixing washer
17
Jean Young S
Kim Ju D
Lee Jong G
Sung Baik H
Yoon Young K
Cranmer Laurie K.
Pillsbury & Winthrop LLP
Samhongsa Co. Ltd.
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