Chairs and seats – Movable bottom – Tiltable
Reexamination Certificate
2003-03-04
2003-11-11
Brown, Peter R. (Department: 3636)
Chairs and seats
Movable bottom
Tiltable
C297S317000, C297S374000
Reexamination Certificate
active
06644743
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a chair chassis for improving supporting stability when the backrest of the chair is in a tilted state.
2. Description of the Related Art
FIG. 7
of the drawings illustrates a conventional chair comprising a base
1
′, a support frame
2
′, a seat
3
′, and a backrest
4
′. The base
1
′ includes a post
11
′ in a central area thereof. The support frame
2
′ is formed by means of bending a metal tube and includes a bottom connected to the post
11
′. The support frame
2
′ further includes a connecting block
21
′ on each of two sides thereof, with a positioning rod
22
′ attached to each connecting block
21
′. The backrest
4
′ is connected to a rear of the support frame
2
′ at two sections of the support frame
2
′. The seat
3
′ has a rear end connected to a bottom of the backrest
4
′. Two sliding rods
31
′ are respectively provided to undersides of two sides of the seat
3
′ and extended through the connecting blocks
21
′. When the backrest
4
′ is tilted rearward, the seat
3
′ shifts and the sliding rods
31
′ are moved accordingly. Further, the positioning rods
22
′ can be operated to be engaged with the sliding rods
31
′ for retaining the backrest
4
′ in the desired inclination angle.
However, when the backrest
4
′ is tilted rearward, the backrest
4
′ is not supported at its central area, failing to provide a stable support while the user lying his or her back in the backrest
4
′. Further, the sliding rods
31
′ respectively slide along the connecting blocks
21
′ while the seat
3
′ is moving such that the sliding rods
31
′ are apt to shift from their normal position or the sliding rods
31
′ are apt to bend and deform, causing the sliding rods
31
′ to be stuck in the connecting blocks
21
′. Further, the level of the seat
3
′ is not adjustable and thus not suitable for users of different heights. Further, the support frame
2
′ formed by means of bending cannot be folded after the chair is disassembled, causing inconvenience to transport and storage.
FIG. 8
of the drawings illustrates another conventional chair that includes a chassis
6
′ attached to an underside of a seat
5
′ and a backrest
7
′ attached to a rear of the seat
5
′. An elastic means
61
′ is provided in the chassis
6
′ so that the front end of the seat
5
′ is moved upward when the backrest
7
′ is tilted rearward. However, the center of gravity of the user sitting in the chair is moved rearward while the backrest
7
′ is tilted rearward. As a result, the user might fall from the chair and thus be injured.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a chair chassis for improving supporting stability by moving the seat forward when the backrest of the chair is in an inclined state.
Another object of the present invention is to provide a chair chassis that limits the maximum inclination angle of the backrest.
A further object of the preset invention is to provide a chair chassis allowing easy assembly and transport convenience.
A chair in accordance with the present invention includes:
a chair base;
a seat mounted on top of the chair base;
a backrest pivotally attached to a rear of the seat, the backrest including a support rod mounted thereon; and
a chassis mounted below the seat, the chassis including a base, a positioning mechanism, a movable member, and a support frame;
the base including a rear end fixedly connected to the support frame, the base including an intermediate portion for connection with the positioning mechanism, the base further including a front end on which two guide plates are mounted for connecting with a front end of the movable member, each guide plate having a guide slot;
the positioning mechanism including at least one positioning plate and a control rod, said at least one positioning plate being mounted to the base and including an end connected to a rear end of the movable member, a top having a hole defined therein, and an intermediate portion having a slot defined therein, the control rod controlling said at least one positioning plate to move between a loosened position and a tightening position for retaining the backrest in a desired inclination angle;
the movable member including an upper end fixed to the seat, a front axle rod being mounted to a front end of the movable member and extending through the guide slots of the guide plates of the base, a rear axle rod being mounted to a rear end of the movable member and extending through the hole of said at least one positioning plate;
the support frame including a bottom fixed to a rear end of the base and a top pivotally connected to the support rod of the backrest;
wherein when the backrest is tilted rearward, the seat moves forward and urges the movable member to shift, with the front axle rod sliding along the guide slots of the guide plates, and with said at least one positioning plate moving together with the rear axle rod.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 2400588 (1946-05-01), McArthur
patent: 4045081 (1977-08-01), Ueno
patent: 4068888 (1978-01-01), Bottemiller
patent: 5211444 (1993-05-01), Kjellman
patent: 5340194 (1994-08-01), Neumuller
patent: 5423595 (1995-06-01), Hancock
patent: 6467842 (2002-10-01), Lu
patent: 6467845 (2002-10-01), Chen
Baxley Charles E.
Brown Peter R.
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