Patent ID: 7241120

Claim:
A piston machine, comprising a cylindrical wall ( 2 ) defining a swept volume ( 1 ) and having a plurality of gas inlet openings ( 5 ): a gas outlet valve ( 7 ); a piston ( 3 ) reciprocating in the swept volume ( 1 ) and having a piston head ( 12 ) formed as a valve having a plurality of openings ( 14 ) provided in the piston head ( 12 ); and magnetic forcelocking means ( 16 , 21 ; 18 , 24 ) for retaining the plurality of openings ( 14 ) in one of open condition and closed condition thereof, dependent on the gas flow through the magnetic forcelocking means, and including a magnetic diaphragm ( 16 ) displaceable between a first position in which the magnetic diaphragm closes the plurality of openings ( 14 ), and an open positioning in which the plurality of openings are open, and a magnetic element ( 21 , 22 ) for retaining the magnetic diaphragm ( 16 , 18 ) in the first position thereof, the magnetic diaphragm being displaced into the open position thereof when a pressure force acting on the magnetic diaphragm as a result of a pressure difference between an operational volume of the piston machine and the swept volume, exceeds a magnetic force applied by the magnetic element to the magnetic diaphragm for retaining the magnetic diagram in the first position thereof.