Patent ID: 7393186

Claim:
A multistage compressor comprising: two movement converting scotch yoke means driven by the same driving shaft for converting a rotating movement to a linear reciprocating movement; first, and second pistons connected to one of the two movement converting means in opposite directions for making linear reciprocating movements; and third, and fourth pistons connected to the other one of the two movement converting means in opposite direction and arranged at an angle to the first and second pistons for making linear reciprocating movements, wherein at least two of the first to fourth pistons are operative as first stage compression pistons, and at least one of the rest of the pistons are operative as a second stage compression piston, wherein the two movement converting scotch yoke means includes scotch yokes, and the scotch yokes comprise one pair of wedge members each having a sloped surface, and an elastic member having one end fixed to the wedge member and the other end fixed to a predetermined position for pressing the wedge member.