Scroll-type compressor

Claim 1

A scroll-type compressor comprising an orbital scroll member and a stationary scroll member each having a disc-shaped end plate and a spiral wrap protruding upright from said end plate, said scroll members being assembled together with the wraps meshing with each other to define compression chambers therebetween, means for causing an orbital movement of said orbital scroll member without permitting said orbital scroll member to rotate around its own axis, a discharge port formed in a central portion and a suction port formed in a peripheral portion of said end plate of said stationary scroll member, whereby, as said orbital scroll member makes orbital movement, said compression chambers are moved towards the center while decreasing their volumes to thereby progressively compress a gas drawn through said suction port and to discharge the compressed gas through said discharge port, a gas passage means formed in a thickness of the end plate of said stationary scroll member for communication with a gas suction chamber formed between the scroll members, said gas passage means extending in an axial direction of said scroll members at a position where said gas passage means partially overlaps with a portion of said gas suction chamber near a wrap end portion of said spiral wrap of said stationary scroll member so that said gas passage means has an opening formed at a lateral side thereof for communication with said gas suction chamber, said opening having a width smaller than a width of said gas passage means and extending substantially over an entire height of said wraps, and a check valve means disposed in the gas passage means and including a valve plate resiliently urged for controlling a communication of said gas passage means with said gas suction chamber, said passage means being adapted to serve as a guide for allowing said valve plate to slide therein in an axial direction of said scroll members.