Abstract: A piston assembly for a double-acting engine such as a double-acting Stirling engine. A pair of sealing rings located on opposite sides of a sealing washer are positioned between a base section and a dome section of a piston head. These sealing rings are alternatively urged into sealing engagement with the cylinder bore as the piston reciprocates. A single sealing ring design is also disclosed in which the sealing ring is urged into constant sealing engagement by positive pressure accumulated with an interior cavity in the piston head.

Abstract: A crosshead system for a swashplate engine such as a Stirling cycle type. A plurality of crossheads are constrained to move in a reciprocating fashion by travelling along a pair of parallel guide rods. The crosshead system further includes a mechanism for adjusting a clearance between the crosshead elements and the opposed parallel face surfaces of the rotating swashplate. The adjustment mechanism includes a threaded adjuster cup which is maintained in a lock position through a fastener which drives a conical cone into the conical inside surface of the adjuster sleeve thus fixing its rotated and hence linear position.

Abstract: A Stirling engine having a modular construction including a drive case and a cylinder block with generally flat mounting surfaces that face each other. The cylinder block includes cylinder bores and cooler bores that are perpendicular to the cylinder block mounting surface. Piston rods extend through the plane defined by the cylinder block mounting surface and couple piston assemblies positioned within the cylinder bores to a drive shaft. Piston rod seals contain a working gas present within the cylinder block from leaking into the drive case. The same basic engine components may be used with either sliding contact rod seals or bellows or other types of hermetic sealing elements.