Patent ID: 9255477
Filing Date: 2016-02-09
CPC Classification: F01B,F04B,F16J

Claim Text:
1. A rocking piston type compressor in which a piston rod is rockingly slidable within a cylinder, the compressor comprising: a lip ring configured to seal between the cylinder and piston rod, the lip ring being provided on a leading end portion of the piston rod and including a bottom portion in a circular plate shape and a lip portion rising from an entire peripheral edge of the bottom portion along the cylinder; and an expansion member provided on an inside of the lip portion and configured to outwardly expand the lip portion at a distal-most end of the lip portion, wherein the expansion member comprises a circular ring spring a portion of the periphery of which is cut out, wherein the circular ring spring is deformed to have an elliptic shape when the ring spring is disposed inside the lip portion, wherein the ring spring is formed such that a major axis direction of the elliptic shape of the ring spring corresponds to a rocking direction of the piston rod, and wherein the rocking piston type compressor further comprises: a ring holder provided on the leading end portion of the piston rod and configured to fix the lip ring, wherein a peripheral groove into which the ring spring fits is formed on an outer peripheral surface of the ring holder adjacent the distal-most end of the lip portion such that the ring spring contacts the distal-most end of the lip portion, wherein the peripheral groove comprises a non-groove portion in a peripheral direction, and wherein the non-groove portion is formed in one side peripheral edge of the ring holder in a rocking direction of the piston rod.