Abstract: A gearing system includes a pair of gear support plates (5,10) arranged to rotate about parallel but offset axes (9,14) with the plates extending parallel to each other in parallel radially extending planes. Each plate includes axially extending teeth (40,45) having concave (43,45) and convex opposed surfaces. The teeth are interdigitated axially such that various pairs of interdigitated teeth will be in cooperating surface contact. Rotation of each support plate about its own axis causes the teeth to orbit relative to each other and engage in a driving relationship in a smooth manner, with the convex portion of certain teeth engaging smoothly with the concave portion of adjacent teeth. In one embodiment, the gear teeth take the form of section of lune shaped elements. In another embodiment, the gear teeth take the form of truncated involutes. In still a further embodiment, the teeth are constituted by multi-faceted polygons.

Abstract: A split Stirling refrigerator includes a pneumatically driven displacer, the displacer is driven substantially through an entire stroke by the pressure differential across a piston element extending from the displacer. A small linear trimming motor is provided to assure proper phasing of the displacer movement with the refrigerator pressure wave, to prevent overstroke, and to assure complete stroke of the displacer.