Information
-
Patent Grant
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6692077
-
Patent Number
6,692,077
-
Date Filed
Thursday, March 27, 200321 years ago
-
Date Issued
Tuesday, February 17, 200420 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 297 34419
- 297 4631
- 248 404
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International Classifications
-
Abstract
A chair height adjustment mechanism includes a lever positioned to overlay a valve opening member of a height adjusting cylinder. The lever may be depressed by a cam on a control arm when the control arm is rotated. The depressed lever then depresses the valve opening member. Depression of the lever through the rotation of the control arm may give finer control to the depression of the valve opening member than is conventional.
Description
FIELD OF THE INVENTION
The present invention relates to height adjustable chairs and, in particular, to a height adjustment mechanism for such chairs.
BACKGROUND
As the users of chairs are of myriad sizes, various aspects of some chairs have been made adjustable. One such aspect is the height of the seat. Typically, the adjustability of the height of the seat is provided by a gas cylinder having two-chambers separated by a normally closed valve. Such a gas cylinder generally terminates in a valve opening member at its top end, which valve opening member is biased to an extended position whereat the valve is closed. A user actuator is supplied to depress the valve opening member in order to open the cylinder valve to permit height adjustment of the seat. A known user actuator comprises a lever tiltably mounted in a housing above the valve opening member. The lever often terminates in a paddle. With such an actuator, the user may depress the valve opening member by raising the paddle. Such an actuator may have a limited range of movement and, therefore, limited granularity in pressure applied when raising the paddle to depress the valve opening member.
SUMMARY
A chair height adjustment mechanism includes a lever positioned to overlay a valve opening member of a height adjusting cylinder. The lever may be depressed by a cam on the end of a control arm when the control arm is rotated. When the lever is depressed it depresses the valve opening member.
Advantageously, the control arm of such a chair height adjustment mechanism preferably rotates through about 90 degrees, thereby providing a greater range of movement than typical rod-type chair height adjustment mechanisms. The greater range of movement allows for finer granularity in applying pressure to depress the valve opening member and therefore allows finer adjustments to the chair height.
In accordance with an aspect of the present invention there is provided a height adjustment mechanism for a chair. The height adjustment mechanism includes a second class lever pivotally attached to a main frame, the lever overlying an opening for reception of a valve opening member of a height adjusting cylinder, a control arm supported by the main frame and a cam mounted on the control arm. The cam is positioned to depress the lever, responsive to rotation of the control arm, such that the lever depresses the valve opening member when the valve opening member is received by the opening.
In accordance with an aspect of the present invention there is provided a chair. The chair includes a height adjusting cylinder having a control valve and a valve opening member adapted to open the control valve, a seat and a height adjustment mechanism adapted to secure the seat to the height adjusting cylinder. The height adjustment mechanism includes a second class lever pivotally attached to a main frame, the lever overlying the valve opening member of the height adjusting cylinder, a control arm supported by the main frame and a cam mounted on the control arm. The cam is positioned to depress the lever, responsive to rotation of the control arm, such that the lever depresses the valve opening member.
In accordance with an aspect of the present invention there is provided a height adjustment mechanism for a chair. The height adjustment mechanism includes a pivot bar mounted to a main frame, a lever pivotally attached to the pivot bar, the lever overlying an opening for reception of a valve opening member of a height adjusting cylinder, a control arm supported by the main frame, a cam mounted on the control arm, the cam positioned to depress the lever, responsive to rotation of the control arm, such that the lever depresses the valve opening member when the valve opening member is received by the opening and a biasing member to bias the lever against the cam and away from the opening.
In accordance with an aspect of the present invention there is provided a chair. The chair includes a height adjusting cylinder having a control valve and a valve opening member adapted to open the control valve, a seat and a height adjustment mechanism adapted to secure the seat to the height adjusting cylinder. The height adjustment mechanism includes a pivot bar mounted to a main frame, a lever pivotally attached to the pivot bar, the lever overlying the valve opening member of the height adjusting cylinder, a control arm supported by the main frame, a cam mounted on the control arm, the cam positioned to depress the lever, responsive to rotation of the control arm, such that the lever depresses the valve opening member and a biasing member to bias the lever against the cam and away from the opening.
Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
In the figures which illustrate example embodiments of this invention:
FIG. 1
is a schematic side view of a chair including an embodiment of the subject invention;
FIG. 2
is a schematic top view of a chair adjustment mechanism including a lever overlaying a valve opening member according to an embodiment of the present invention;
FIG. 3A
is a sectional view of the chair adjustment mechanism of
FIG. 2
taken substantially along line
3
—
3
of
FIG. 2
, wherein the lever is in a rest position;
FIG. 3B
is a sectional view of the chair adjustment mechanism of
FIG. 2
taken substantially along line
3
—
3
of
FIG. 2
, wherein the lever is in a depressed position; and
FIG. 4
is a schematic, underside, perspective, exploded view of the chair control mechanism of FIG.
2
.
DETAILED DESCRIPTION
In the schematic side view of a chair
10
presented in
FIG. 1
, the chair
10
includes a seat
12
secured to a chair height adjustment mechanism
16
that is secured to a height adjusting cylinder
14
.
As illustrated in more detail in
FIG. 2
, the chair height adjustment mechanism
16
includes a main frame
20
. A lever
22
is pivotally mounted to the main frame
20
on a pivot bar
24
. The main frame
20
has side walls
32
that support the pivot bar
24
. The lever
22
is positioned along the pivot bar
24
so that the lever
22
will at least partially overlie a gas cylinder aperture
26
in which the height adjusting cylinder
14
, for instance, a gas cylinder, will normally be installed. More particularly, the lever
22
is positioned along the pivot bar
24
so that the lever
22
at least partially overlies a valve opening member
15
used to actuate the gas cylinder.
A control arm
28
may be supported by a bushing
30
extending outwardly from one side wall
32
of the main frame
20
so that a cam
34
, at an inside end
35
of the control arm
28
, is positioned to overlie the lever
22
. An outside end
37
of the control arm
28
is provided with a paddle
36
to assist the manual rotation of the control arm
28
. As illustrated in
FIG. 4
, a channel
48
extends inward from the end
50
of the paddle. The side of the paddle
36
opposite the channel
48
is provided with an aperture
52
(see FIG.
2
).
An outer end
44
of the bushing
30
(the end that is not connected to the main frame
20
) may be provided with two extensions (or stops)
46
defining two notches.
A spring
38
, coiled around the pivot bar
24
, biases the lever
22
away from the valve opening member
15
and towards the cam
34
at the inside end
35
of the control arm
28
. The biasing of the lever
22
against the cam
34
acts to eliminate play in the lever
22
when the lever
22
is not being used to adjust the height of the seat.
The control arm
28
, once installed in the bushing
30
has limited axial freedom. This is due to a fixing pin
40
abutting the outer end
44
of the bushing
30
once the control arm
28
is installed in the bushing
30
, thereby restricting inward movement of the control arm
28
. Similarly, to restrict outward movement of the control arm
28
, the control arm
28
may have a flange
29
. The flange
29
abuts the side wall
32
of the main frame
20
when the control arm
28
is installed in the bushing
30
.
During installation, the control arm
28
is inserted into the bushing
30
from the inside of the main frame
20
. The flange
29
acts to limit the extent to which the control arm
28
is allowed to be inserted into the bushing
30
. The fixing pin
40
may then be inserted into a passageway
42
in the control arm
28
(see
FIG. 4
) such that the fixing pin
40
projects from each end of the passageway
42
. Once the control arm
28
has been inserted into the bushing
30
and the fixing pin
40
has been installed in the control arm
28
, the extensions
46
of the bushing
30
limit rotation of the control arm
28
by abutting the fixing pin
40
at the clockwise and counter-clockwise extent of the allowed rotation.
Additionally, the fixing pin
40
may be used to mount the paddle
36
to the control arm
28
as follows. During the installation of the fixing pin
40
in the control arm
28
, the installer may pause while the fixing pin
40
is partially inserted such that it projects from one end of the passageway
42
in the control arm
28
, but not from the other. At this point, open end
50
of the paddle
36
may be slid over the bushing
30
such that the projecting fixing pin
40
passes along the channel
48
of the paddle
36
. Once the paddle
36
has been received over the bushing
30
to the extent allowed by the channel
48
, the installation of the fixing pin
40
may continue such that the fixing pin projects out from the other side of the control arm
28
and is received in the aperture
52
of the paddle
36
.
The size and shape of the notches in the bushing
30
may allow the paddle
36
, and consequently the control arm
28
, to be rotated through about
90
degrees. The biasing of the lever
22
against the cam
34
acts to maintain, in the absence of an overcoming force, the combination of the paddle
36
and the control arm
28
at one end of their rotational path.
In operation, a user may rotate the control arm
28
such that the cam
34
depresses the lever
22
.
FIG. 3A
illustrates the lever
22
in a lever rest position. In the rest position, the lever overlays the valve opening member
15
. Since gas cylinders manufactured by diverse parties may have valve opening members having slightly different heights, it is possible that the lever
22
will, in some cases, touch the valve opening member
15
when in the lever rest position and, in other cases, there may be clearance between the lever
22
and the valve opening member
15
when in the lever rest position.
As illustrated in
FIG. 3B
, as a result of rotation of the control arm
28
, the cam
34
depresses the lever
22
. The lever
22
, when depressed by the cam
34
, depresses the valve opening member
15
thereby allowing the user to change the height of the chair.
As will be apparent to a person skilled in the art, if a downward force, say, gravity on a person sitting in seat
10
(FIG.
1
), is applied to the height adjusting cylinder
14
when the lever
22
depresses the valve opening member
15
, the height of the chair will be reduced. In the absence of such a downward force when the lever
22
depresses the valve opening member
15
, the height of the chair will be increased.
Advantageously, the user may control the depth of depression of the valve opening member
15
with fine granularity. The degrees of control depends on the class of lever used and the length of the lever. As shown, the height adjustment mechanism
16
is a second class lever system with the length of the lever
22
extending through a majority of the long dimension of the main frame
20
. Through the fine granularity control of the opening of the valve afforded by the height adjustment mechanism
16
, the user may control the speed of adjustment of the height of the chair. For instance, for a very slight adjustment in the height of the chair, a very slow speed of adjustment would be preferred.
As will be apparent to a person skilled in the art, many shapes are available for the cam
34
, besides that which is disclosed by the drawings. Additionally, it will be apparent to a person skilled in the art that the cam
34
need not be positioned precisely at the inside end
35
of the control arm
28
. The control arm
28
could, for example, extend from one side wall
32
of the main frame
20
to the other side wall
32
, with the cam
34
positioned along the control arm
28
to depress the lever
22
.
As will be apparent to a person skilled in the art, the control arm
28
may be manufactured of a material that is easily moldable to the required shape, such as a plastic. Additionally, the lever
22
may be manufactured of a material that prevents deflection during activation, such as steel.
Other modifications will be apparent to those skilled in the art and, therefore, the invention is defined in the claims.
Claims
- 1. A height adjustment mechanism for a chair comprising:a second class lever pivotally attached to a main frame, said lever overlying an opening for reception of a valve opening member of a height adjusting cylinder; a control arm supported by said main frame; and a cam mounted on said control arm, said cam positioned to depress said lever, responsive to rotation of said control arm, such that said lever depresses said valve opening member when said valve opening member is received by said opening.
- 2. The height adjustment mechanism of claim 1 further comprising a pivot bar mounted to said main frame adapted to pivotally support said lever.
- 3. The height adjustment mechanism of claim 2 further comprising a biasing member to bias said lever against said cam and away from said opening.
- 4. The height adjustment mechanism of claim 3 wherein said biasing member is a coil spring wrapped around said pivot bar, where opposite ends of said coil spring are respectively biased against said lever and said main frame.
- 5. The height adjustment mechanism of claim 1 further comprising a paddle mounted to said control arm.
- 6. The height adjustment mechanism of claim 5 wherein said paddle extends radially from said control arm.
- 7. The height adjustment mechanism of claim 1 further comprising a bushing mounted to said main frame to support said control arm.
- 8. The height adjustment mechanism of claim 7 wherein said bushing includes stops to limit said rotation of said control arm.
- 9. The height adjustment mechanism of claim 8 wherein said stops limit said rotation to about 90 degrees.
- 10. A chair comprising:a height adjusting cylinder having a control valve and a valve opening member adapted to open said control valve; a seat; a height adjustment mechanism adapted to secure said seat to said height adjusting cylinder, said height adjustment mechanism including: a second class lever pivotally attached to a main frame, said lever overlying said valve opening member of said height adjusting cylinder; a control arm supported by said main frame; and a cam mounted on said control arm, said cam positioned to depress said lever, responsive to rotation of said control arm, such that said lever depresses said valve opening member.
- 11. A height adjustment mechanism for a chair comprising:a pivot bar mounted to a main frame; a lever pivotally attached to said pivot bar, said lever overlying an opening for reception of a valve opening member of a height adjusting cylinder; a control arm supported by said main frame; a cam mounted on said control arm, said cam positioned to depress said lever, responsive to rotation of said control arm, such that said lever depresses said valve opening member when said valve opening member is received by said opening; and a biasing member to bias said lever against said cam and away from said opening.
- 12. A chair comprising:a height adjusting cylinder having a control valve and a valve opening member adapted to open said control valve; a seat; a height adjustment mechanism adapted to secure said seat to said height adjusting cylinder, said height adjustment mechanism including: a pivot bar mounted to a main frame; a lever pivotally attached to said pivot bar, said lever overlying said valve opening member of said height adjusting cylinder; a control arm supported by said main frame; a cam mounted on said control arm, said cam positioned to depress said lever, responsive to rotation of said control arm, such that said lever depresses said valve opening member; and a biasing member to bias said lever against said cam and away from said opening.
US Referenced Citations (6)