Scroll-type machine having compact Oldham coupling

Claim 1

A scroll-type machine, comprising: a non-orbiting scroll member; a fixed body having a portion which is generally circular about the machine axis; an orbital scroll member mounted for orbital movement about said axis with respect to said body, said circular portion of said fixed body defining a surface supporting said orbital scroll member; mounting means for mounting said non-orbiting scroll to said fixed body; means for causing said orbital scroll member to orbit with respect to said body; and compact Oldham coupling means for preventing rotational movement of said orbital scroll member with respect to said body, said compact Oldham coupling being positioned between said circular body portion and said mounting means and comprising (1) means defining generally diametrically aligned first abutment surfaces on said body, (2) means defining generally diametrically aligned second abutment surfaces on said orbital scroll member, arranged at right angles to said first abutment surfaces, (3) a transversely disposed annular ring member generally surrounding said circular body portion, the inner peripheral surface of said ring member being non-circular in configuration, comprising at opposite ends circular arcs of equal radius, the centers of curvature of said arcs being spaced apart a predetermined distance, and relatively straight portions connecting said arcs whereby the area of said supporting surface defined by said circular portion may be maximized, (4) a first pair of keys on one face of said ring member in linear sliding engagement with said first abutment surfaces, and (5) a second pair of keys on the opposite face of said ring member in linear sliding engagement with said second abutment surfaces.