Patent ID: 8082838

Claim:
A double-acting cylinder and piston mechanism comprising: a cylinder ( 1 ) substantially closed at both ends by front ( 5 ) and rear ( 7 ) end walls, a piston ( 8 ) axially displaceable within the cylinder ( 1 ), a first region ( 6 ) defined between the piston ( 8 ) and the rear end wall ( 7 ) of the cylinder ( 1 ) and a second region ( 4 ) defined between the piston ( 8 ) and the front end wall ( 5 ) of the cylinder ( 1 ), a piston rod ( 2 ) extending from the piston ( 8 ) through the front end wall ( 5 ) of the cylinder ( 1 ), an air inlet port ( 19 ) for communication with said first region ( 6 ) of the cylinder ( 1 ), and at least one exhaust vent ( 14 ) which is exposed during axial displacement of the piston ( 8 ) for release of air delivered to the first region ( 6 ) of the cylinder ( 1 ) through the air inlet port ( 19 ), wherein the piston ( 8 ) is of sufficient length to prevent communication between the second region ( 4 ) and the exhaust vent ( 14 ) so that a static air pressure may be maintained in the second region ( 4 ) of the cylinder ( 1 ) to cushion impact between the piston ( 8 ) and the front end wall ( 5 ) of the cylinder ( 1 ).