Abstract: A low air loss patient support system includes a plurality of identical multi-chambered inflatable sacks. A restrictive flow hole connects two adjacent chambers disposed predominately to one side of the centerline of the sack, and each side is separately pressurizable under the control of a microprocessor and a plurality of pressure control valves with pressure transducers and a plurality of flow diverter valves for switching between different modes of configuring the manner in which the sacks are pressurized. The system includes a modular manifold for mounting the pressure control valves, and a modular support member for mounting the sacks via quick-disconnect couplings and having air flow channels defined therethrough. The support system effects a method of rotating or tilting the patient that depressurizes one side of the sacks while increasing the pressurization of the opposite side of the sacks.

Abstract: A cycle timer circuit for electrical discharge machining. Operation of the electrode is controlled by a pair of solid state timers working in timed relationship, one with the other, to provide an up time duration of greater magnitude than the down time duration.