Abstract: Improved sealing means are provided for a motor, engine, or pump having a piston mounted for orbital motion within a cylinder housing, with the housing including radial faces and a plurality of combustion chambers. The improved sealing means are disposed in a groove in at least one of the radial faces of the piston to prevent leakage of working fluid in a circumferential direction between adjacent combustion chambers. The sealing means is comprised of an annular seal ring including an annular band, the band having a plurality of spaced extension members which define pockets therebetween. Each of the pockets has disposed therein a circumferential sealing member and spring means, with each of the spring means operating to bias the annular band into engagement with one of the radial faces of the cylinder housing to prevent leakage of working fluid in a radial direction.

Abstract: An engine, pump or motor is disclosed of a type generally similar to the "Wankel" engine, except that the present invention is characterized by purely orbital motion of the piston to produce rotation of the output shaft. Preferably the shaft has two eccentric sections in radial alignment, the first eccentric axis being displaced from the main axis, one half the displacement of the second eccentric axis from the main axis. A pinion is rotatably mounted about the first eccentric axis. A fixed internal ring gear is fixed against rotation and mounted about the main axis so as to engage the pinion at a point in radial alignment with the two eccentric axes. An orbital ring gear is preferably identical to the fixed ring gear and rotatably mounted about the second eccentric axis so as to engage the pinion at a point on the pinion diametrically opposite the point of engagement of the pinion and the fixed ring gear. The piston is also rotatably mounted about the second eccentric axis and fixed to the orbital ring gear.