A pressure pump for fluids having a pressure member 12, 12a of generally circular periphery, means 14, 14a for moving the pressure member in an orbital motion about an axis of rotation, and a sleeve member 16, 16a made of a pair of hinged jaws 22, 22a positionable about the pressure member and spaced...http://www.google.es/patents/US4540351?utm_source=gb-gplus-sharePatente US4540351 - Pressure pump having jaws and end-slots
