Abstract: A cushion for the seat of a chair is provided, having at least two groups of cyclically inflatable tubes (4, 6, 8, 10), each group comprising at least one tube. Control means (18) inflates and deflates each group sequentially. The cushion also has a buffer chamber (12, 14) maintained by the control means (18) in communication with the inflated group or groups of cyclically inflatable tubes. The buffer chamber comprises at least one inflatable buffer tube which provides a part of the sitting surface of the chair.

Abstract: A cushion for the seat of a chair, has at least two groups of inflatable tubes arranged in a side-by-side relationship and oriented in a direction corresponding to the front to back direction of the chair seat. The tubes of each group are inflatable together. The first group is a single tube or two or more adjacent tubes, and the other group is at least two spaced apart tubes arranged on opposite sides of the first group of tubes. The groups of tubes are inflatable sequentially. Symmetrical but periodically varying support for the user is thus provided.

Abstract: A fluid distributor for sequentially distributing pressurized fluid from at least one inlet port to a plurality of distribution ports and exhausting fluid from said distribution ports to at least one exhaust port, said distributor having a valve actuated by pressure of fluid supplied at said inlet port and arranged to close said exhaust port when said fluid pressure drops below a predetermined minimum. The distributor is suitable for use in conjunction with an inflatable human body support.