Patent ID: 7909014

Claim:
An oscillating piston engine, comprising: a housing, a first piston arranged in said housing, said first piston revolving in said housing about an axis of rotation which is fixed in relation to said housing, and revolving about said axis of rotation reciprocating pivoting movements about a pivot axis extending perpendicularly to said axis of rotation between a first end position and a second end position, a running element mounted to said first piston, a control cam arranged in said housing, wherein said running element runs, as said first piston revolves about said axis of rotation, along said control cam, wherein said control cam is configured to derive said pivoting movements of said first piston when said running element runs along said control cam, and wherein a negative-pressure source for generating a negative pressure applied to a back of said first piston is return means for assisting guiding of said first piston at least from said first end position to said second end position.