Abstract: A piston-operated machine is disclosed having a crank shaft and an intermediate crank section, the axis of the crank section being oblique to the axis of the crank shaft. The crank section passes rotatably and centrally through a wobble plate, and the center of the wobble plate lying on a prolongation of the axis of the crank shaft. A plurality of cylinders are provided having axes parallel to and equally spaced from the axis of the crank shaft. A piston in each cylinder is mounted on a piston rod extending coaxially from the cylinder to a respective connection on the wobble plate spaced from the center of the wobble plate. Each piston rod is rotatably but non-slidably engaged in a thrust member eccentrically rotatable in a thrust plate mounted to rotate about the same axis as the wobble plate.