(57) The seat (2) of a chair is mounted on a base (1) by pivotal support members (10,11)
which form, together with the seat and base, a quadrilateral linkage having generally
horizontal axes extending transversely of the seat, the linkage extending generally
between the front and rear of the seat. The spacing of the pivot axes of the support
members (10,11) are selected so that the seat is movable relative to the base. Specifically,
the seat portion (3) of the seat is movable between a rearwardly inclined lower position
and a forward upper position. The back rest portion (4) of the seat (2) may be connected
for movement with the rear-most one of the support members (11) so that it inclines
relative to the seat portion (3) as the seat portion moves relative to the base.
Resilient biassing means, as shown in the form of a gas spring (16), is provided for
biassing the seat portion (3) to its forward upper position and for counterbalancing
the weight of the user, the user then being able to move the seat portion (3) to its
rearward position by adjustment of the user's position on the chair. Locking means
may be provided separately or in association with the biassing means, operable by
the user to lock the chair in a desired position.
|
|
