Patent ID: 7117840

Claim:
A rotary piston machine comprising: a housing defining a prismatic cavity with a cavity wall therein, the cross section of said prismatic cavity being a cavity oval which is formed by circular arcs of, alternatively, smaller and larger radii, an order of said cavity oval being defined by a first number of pa smaller radius and larger radius circular arcs, a rotary piston guided for rotary movement in said cavity and having a cross section which is also an oval formed by circular arcs of, alternatively, said smaller and larger radii, an order of said piston oval being defined by a second number of pairs of said smaller radius and larger radius circular arcs, said order of said cavity oval being by one smaller than the order of said piston oval, said rotary piston moving in consecutive intervals of motion from one blocking position, in which a pair of said smaller and larger radii circular arcs of said rotary piston engage a pair of smaller and larger radii, respectively, circular arcs of said cavity, to an adjacent end position, in which another pair of said smaller and larger radii circular arcs of said rotary piston engage a pair of smaller and larger radii, respectively, circular arcs of said cavity, said rotary piston, during said consecutive intervals of motion rotating, in the same rotational direction, alternatively about one of two different axes, said axes being located, relative to said cavity, in the centers of curvature of said larger radius circular arcs, in each such interval of motion one larger radius circular arc of said rotary piston sliding along a larger radius circular arc of said cavity, while a smaller radius circular arc of said rotary piston engages an opposite larger radius circular arc of said cavity, transmission means for transmitting rotary motion about said two axes, whereby, when said rotary piston reaches a blocking position, there is an associated larger diameter cavity circular arc, in which the larger diameter piston circular arc was slidably guided during the preceding interval of motion, and means for temporarily providing, when said rotary piston has reached one of said blocking positions, reduced rotary speed of the rotary motion of said rotary piston about that one of said axes which is located in the center of curvature of said associated larger radius circular arc, as compared to the rotary speed about the other axis.