Patent ID: 7934910

Claim:
A piston displacement device for a reciprocating compressor, comprising: a piston linearly reciprocated in a cylinder and having a stroke length varied by a reciprocating motor; a spring supporting unit located beneath the piston; a plurality of resonance springs bearing against the spring supporting unit; and a piston transfer unit for moving the piston forward or backward relative to the spring supporting unit according to a capacitance variation of a compressor and thereby maintaining the same top dead center, wherein one of the piston and the spring supporting unit is provided with a plurality of guide holes along a circumferential direction, and a plurality of guide bars are formed in the other of the piston and spring supporting unit, wherein the guide bars are inserted in the guide holes and are made to move therein, and wherein the piston adheres to the spring supporting unit when the piston transfer unit is set for maximum stroke and the piston is spaced from the spring supporting unit when the piston transfer unit is set for small cooling capacity.