Back support control mechanism for a chair or the like

In a back support control mechanism for a chair or the like in which said back support is mounted for movement toward and away from a seat, the improvement for providing adjustable positioning of said back support with respect to said seat in an infinite number of positions in a range of movement of said back support comprising a channel member fixed with respect to said seat, a pressure pad positioned within said channel member and fixed with respect to said back support, said channel member permitting sliding movement of said pressure pad with respect thereto resulting in movement of said back support over said range of movement, and a lever coupled to said pressure pad and movable therewith and with respect thereto and having a cam surface thereon which, in one position of said lever with respect to said pressure pad, bears against said pressure pad, causing the latter to bear against said channel member to fix said pressure pad in position with respect to said channel member and to prevent further movement of said pressure pad, thereby fixing the position of said back support with respect to said seat, in which said back support comprises a tubing that includes a carrier therein that holds said pressure pad, said carrier includes side rails, with said pressure pad being supported between said side rails, said channel member is positioned within said tubing, and said channel member includes tracks along the sides thereof, and said side rails of said carrier ride along said tracks.