Patent ID: 7992408

Claim:
A compressor ( 20 ) comprising: a housing ( 22 ); a crank ( 24 ) carried by the housing for rotation about a crank axis ( 500 ); and a plurality of cylinders ( 30 , 31 , 32 ) defined within the housing, each said cylinder having: an associated piston ( 33 , 34 , 35 ) held within the housing for reciprocal movement at least partially within the cylinder; and a connecting rod ( 44 ) pivotally coupled to the crank ( 24 ) for relative rotation about a proximal axis ( 510 ) and to said associated piston for relative rotation about a distal axis ( 512 ), wherein: a first ( 30 ) of the cylinders has a single associated chamber ( 36 ); a stepped cylinder ( 32 ) of the cylinders has a proximal portion ( 49 ) and a distal portion ( 51 ) separated by a shoulder ( 54 ), the distal portion being smaller than the proximal portion in cross-sectional area transverse to a cylinder axis ( 502 ); the piston ( 35 ) associated with the stepped cylinder has a proximal portion ( 58 ) and a distal portion ( 62 ), the distal portion ( 62 ) smaller than the proximal portion ( 58 ) in cross-sectional area transverse to the cylinder axis ( 502 ); a first compression chamber ( 70 ) exists in the cylinder distal portion beyond the end of the piston; a second compression chamber ( 72 ) exists in the cylinder proximal portion beyond the piston shoulder, the first and second compression chambers being not in series and not in parallel.