Chairs and seats – Movable bottom – Movable independently of back
Reexamination Certificate
2000-06-23
2001-11-20
Barfield, Anthony D. (Department: 3636)
Chairs and seats
Movable bottom
Movable independently of back
C297S447200
Reexamination Certificate
active
06318801
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure for supporting a seat of a height-adjustable chair.
2. Description of the Related Art
The applicant of the present invention has proposed a height-adjustable chair (chair with a height-adjustable seat) with a foldable seat of which height can be adjusted in a stepless manner (refer to Publications of Japanese Examined Utility Model Nos. 1-8204, 4-45562, and 1-11089 and the like). As shown in
FIG. 14
a
, a typical height-adjustable chair comprises a front leg unit
101
on the outer side of an inverted almost U shape, an auxiliary frame
102
disposed on the inside of the front leg unit
101
with a gap, rear legs
103
closably attached to either the front leg unit or the auxiliary frame, a pair of right and left brackets
104
whose rear portions are positioned in the gap between the front leg unit
101
and the auxiliary frame
102
, and a seat
105
attached to the top face on the front side of each of the brackets
104
. In the rear portion of each of the brackets
104
, as specifically shown in
FIG. 14
b
, a front engagement piece
106
and a rear engagement piece
107
for maintaining the angle of the bracket
104
are provided.
As shown in
FIGS. 15
a
and
15
b
, the distance between the front engagement piece
106
and the rear engagement piece
107
is set to be slightly wider than the dimention in the front/rear directions (thickness or diameter) of each of the front leg unit
101
and the auxiliary frame
102
. Consequently, when the bracket
104
is inclined rearward as shown in
FIG. 15
b
, the seat
105
can be moved vertically. When the seat
105
is inclined forward as shown in
FIG. 15
a
, the front and rear engagement pieces
106
and
107
come into contact and engagement with the opposite faces of the front leg unit
101
and the auxiliary frame
102
, so that they are fixed in the position. By retaining a retaining piece (reference numeral
109
in
FIG. 14
b
) provided between the front leg unit
101
and the auxiliary frame
102
by a slit
108
at the rear end of the bracket
104
in the state where the front side of the seat
105
is lifted and folding the rear legs
103
, the chair can be folded.
SUMMARY OF THE INVENTION
The above-mentioned height-adjustable chair has an advantage that the height can be adjusted only by slightly lifting the front end of the seat
105
and inclining the brackets
104
rearward to disengage the front and rear engagement pieces
106
and
107
from the front leg unit
101
and the auxiliary frame
102
. The advantage causes, however, a problem such that the height changes even when the seat
105
is slightly lifted without user's intention. For example, also in the case where the user half rises to his/her feet, pulling the front end of the seat
105
to the front to move the chair forward, the front and rear engagement pieces
106
and
107
of the bracket
104
are disengaged from the front leg unit
101
and the like. When the user sits on the chair, the engagement pieces
106
and
107
have to be re-engaged with the front leg unit
101
and the like at a proper height.
A technical subject of the present invention is to provide a structure for supporting a seat of a height-adjustable chair in which the height of the seat
105
hardly changes even if the user moves the seat
105
a little while maintaining the convenience of the conventional height-adjustable chair.
According to the present invention, there is provided a structure for supporting a seat of a height-adjustable chair, the structure comprising a leg member longitudinally disposed, and a bracket having a front engagement piece and a rear engagement piece which are disposed on the front and rear sides of the leg member, respectively, with spacing larger than the thickness of the leg member, and the bracket being vertically movable along the leg member when the bracket is inclined rearward and being fixed when the bracket is returned forward in a use state and the front and rear engagement pieces come into engagement with the leg member, wherein a frictional stopper is provided on a side face of either the leg member or the bracket, which comes into contact with a side face of the other member with a frictional function in the use state and which is disengaged from the side face in a state where the front side of the bracket is lifted.
The supporting structure can be applied to a height-adjustable chair in which the leg member has two right and left rod members which are arranged with spacing and the rear portion of the bracket is positioned vertically in the spacing between the rod members, in a manner similar to the conventinal chair. In this case, it is preferable that the frictional stopper is a projection provided on a side face of the rear portion of the bracket so as to come into contact with a side face of the rod member in the use state.
When the leg member is constructed by two rod members, preferably, the projections are provided on both faces of the rear portion of the bracket. More preferably, the bracket is a plate member, the projections provided on both faces are projection members of the same shape which are disposed on both faces of the plate member, and each of the projection members has a male shaft and a female shaft. The male shaft penetrates a hole formed in the bracket and fixedly fit into to the female shaft.
Preferably, the frictional stopper is a resilient or elastomeric member made of a high polymer material.
In a supporting structure of the invention, in a use state where the bracket is inclined forward, the front and rear engagement pieces are engaged with the front and rear sides of the leg member to check further forward inclination of the seat. In such a state, since the frictional stopper provided on a side of either the bracket or leg member is abutted against the side face of the other member with a frictional function, the angle and height of the bracket relative to the leg member do not easily change. Even when the front end of the seat is slightly pulled upward to thereby slightly swing the seat rearward, the seat swings merely in the position but is just returned to the original state when the user moves his/her hand off. Therefore, even when the user holds the seat and moves the chair in the front-rear direction, the height of the seat does not change. On the other hand, when the bracket is largely inclined rearward, the engagement between the frictional stopper and the other member is cancelled. Since the front and rear engagement pieces are disengaged from the leg member in such a state, the bracket can be freely moved vertically.
In the case where two right and left rod members are adopted as the leg member, the rear portion of the bracket is positioned between the rod or bar members, and a projection formed on a side face of the rear portion of the bracket is used as the frictional stopper, the projection comes into contact with the inner face of the rod member when the seat is set in the use state, and the projection comes off from the rod member when the seat is inclined rearward. Proper position and range of the projection in the bracket can be selected according to the degree of the rearward inclination of the bracket, at which the projection comes off from the rod member. The supporting structure of the invention can be applied to the conventional height-adjustable chair only by providing the projection on a side face of the r ear portion of the bracket. It is therefore easy to carry out the invention.
When the projections are provided on both faces of the bracket, the angle-maintaining function of the frictional stopper becomes more stable. Further, when the projection members of the same shape are used as the frictional stoppers provided on both faces of the bracket, the parts can be commonly used, the manufacturing cost can be reduced, and the parts management is facilitated.
When the resilient or elastomeric member made of a high polymer material is used as the frictional stopper, a fixing force bas
Barfield Anthony D.
Browdy and Neimark
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