Support column for a chair

摘要

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