Patent ID: 7568895

Claim:
A dual capacity compressor, comprising: a power generating part including a reversible motor and a crank shaft inserted in the motor; a compression part including a cylinder, a piston positioned in the cylinder, and a connecting rod connected to the piston; a crank pin provided at an upper part of the crank shaft, eccentric from an axis of the crank shaft; an eccentric sleeve having an inner circumferential surface that is rotatably fitted within an outer circumferential surface of the crank pin, and an outer circumferential surface that is rotatably fitted to an end of the connecting rod; and a key member engaged with a portion of the eccentric sleeve so as to couple the eccentric sleeve and the crank pin in all rotation directions of the motor and provide for a plurality of compression capacities based on an effective amount of eccentricity and a piston displacement following a change in direction of rotation of the motor, and to prevent relative motion between the crank pin and the eccentric sleeve during operation regardless of the direction of rotation of the motor, wherein the eccentric sleeve includes a balance weight that rotates with the eccentric sleeve so as to shift a center of gravity of the eccentric sleeve during rotation and maintain the engagement between the key member and the eccentric sleeve.