Adjustable arm rest

There is described a tiltable chair including a base member, a seat, a back and a linkage assembly(40) adapted to allow the seat and back to tilt downwardly and rearwardly and to allow pivotal movement of the seat about a pivot axis (54) in substantial alignment with the hip joints of a user. Other aspects of the invention are to provide a vertically adjustable column (42) for supporting the seat of the chair, a support assembly including a frame member (33) having a central opening therethrough and a receptacle formed around the perimeter thereof, a carrier member (362) adapted to fit inside the receptacle, a membrane (210) of elastic material covering the central opening, and a pair of armrests (36) adapted to be mounted to the chair to allow pivotal movement thereof.