Abstract: A swash plate drive mechanism for an axial piston machine is disclosed comprising a pair of yokes with intersecting longitudinal axes and intersecting cross-axes and a swash plate drivingly connected with the pistons and pivotally connected between the yokes for pivotal movement about their cross-axes whereby the swash plate is caused to oscillate and effect double frequency drive between the piston and yokes and wherein the limits of swash plate oscillation are dependent on the angle between the longitudinal axes of the yokes and are fixed or variable and which in the latter event reach zero on alignment of the longitudinal axes.

Abstract: A family of balanceable, variable displacement reciprocating piston engine arrangements is disclosed. The arrangements include multiple parallel cylinders having pistons movable therein in balanceable fashion through a fixed geometry rocker mechanism driving oscillating links which are adjustable to provide control of the piston displacement and compression ratio. Both in-line and side-by-side cylinder arrangements are possible. Even firing intervals are preferably provided.