Patent ID: 6957864

Claim:
A chair comprising: a leg unit; a lower frame having opposite front and rear ends, a base plate secured to said leg unit, spaced-apart side plates extending between said front and rear ends in a longitudinal direction, and a rear plate formed on said base plate and having an upper end; a first pivot extending in a transverse direction relative to said longitudinal direction; an upper frame including a seat-mounting plate disposed above said lower frame, and two side plates that extend downwardly and respectively from two opposite sides of said seat-mounting plate and that are respectively pivoted to said side plates of said lower frame through said first pivot so as to permit pivotal action of said upper frame relative to said lower frame, said seat-mounting plate being spaced apart from said upper end of said rear plate in a vertical direction that is transverse to said longitudinal and transverse directions; an urging mechanism connected to said front end of said seat-mounting plate of said upper frame and said lower frame; and a stopping device including a slide mounted slidably on said seat-mounting plate, and a stopping member formed on said slide, said slide being slidable in said longitudinal direction between a first position, in which said stopping member is offset from said rear plate of said lower frame in said longitudinal direction, and a second position, in which said stopping member is aligned with said rear plate of said lower frame in said vertical direction for preventing pivoting of said upper frame relative to said lower frame, said stopping device further comprising a cam mechanism which includes a cam that is connected movably to said side plates of said lower frame and that is movable in said transverse direction between a releasing position and a restricting position, and a cam follower that is formed on said slide and that engages said cam in such a manner that movement of said cam from said releasing position to said restricting position results in movement of said slide from said first position to said second position, and that movement of said cam from said restricting position to said releasing position results in movement of said slide from said second position to said first position.