Chair control

Abstract

A chair control, having a basic mechanism which can be modified slightly for use in swivel tilt, stenographer's and double action posture chairs. The basic chair control mechanism includes a pair of chair seat supporting arms, a screw post cap which mounts on a chair screw post or a lifting cylinder and a spring housing. The spring housing is pivotally connected at its front end to the screw post cap so that the housing can rotate about a generally horizontal axis. Compression springs are carried in the spring housing and engage an adjustably movable wall at the rear end of the housing. A spring retaining member pivotally mounted on the screw post cap for rotation about a horizontal axis engages the front ends of the springs and is biased for upward rotation by said springs. A pivot pin slidably connects the spring housing and the spring retaining member so that when the spring housing is rotated by tilting of the chair, the spring housing rotates about its pivotal connection to the screw post cap and rotates the spring retaining member about its pivotal mounting, thereby maintaining the spring retaining member in its normal position of engagement with the springs. When used with a swivel tilt chair, i.e. a chair in which the seat and back tilt together, the seat supporting arms are fixed to the spring housing. When used with a stenographer's chair, i.e. a chair in which the seat is fixed horizontally and the chair back tilts relative thereto, the seat supporting arms are fixed to the screw post cap. When the chair control is used with a double action posture chair, i.e. a chair in which the seat and back both tilt relative to the screw post, but through different angles, the chair seat supporting arms are pivotally connected to the screw post cap and slidably mounted relative to the spring housing.