Abstract: A pivotal piston machine or compressor including a disc-like pivotal piston oscillating on a bearing axis, such oscillatory movement being effected by engagement of a roller-type cam follower of a crank arm driven by a crankshaft, with cam surfaces formed on the pivotal piston, and angled member for limiting the oscillating movement at opposite ends of the pivotal stroke of the piston. The angled member serves as a separating wall between two compression chambers and a delivery chamber. A pair of pivotal pistons may be arranged adjacent each other to utilize a common air intake and provide a compound piston machine.

Abstract: An improved peristaltic pump includes a pivotably mounted pressure plate which, together with the pump roller elements, defines the pump chamber. The pivotal mounting of the pressure plate facilitates accessibility to the pump chamber in order to simplify the pump tube loading and unloading procedures. The mounting system for the pressure plate includes a mechanically-advantaged four-bar linkage arrangement which automatically retains the pressure plate in either its fully open or fully closed position as a result of an over-center type locking construction. The pump also includes a mechanism for adjusting the volume flow rate characteristic of a pump tube. This is particularly adaptable for a dual-tube system wherein a predetermined volume flow rate ratio is to be achieved.