Compact Oldham coupling

Abstract

A pair of keys of an Oldham coupling are located on a chord spaced from a diameter and are of a parallelogram shape. The ends of the corresponding slots are located at the same radius whereby a reduced envelope results.

What is claimed is: 
     
       1. A scroll machine having a shell with an axis containing a reference member, a coupling member and a scroll member with said coupling member coacting with said reference member and said scroll member such that said scroll member is held to an orbiting motion with respect to said reference member wherein: said coupling member is generally ring-shaped and has a center and a first pair of keys on a first side with said first pair of keys being located on a chord spaced from said center and said axis;   said first pair of keys being of a parallelogram shape with one pair of opposing sides of said parallelogram being parallel to said chord;   said scroll member having a pair of slots parallel to said chord for receiving said first pair of keys and coacting therewith;   each slot of said pair of slots extending to an outer edge of said scroll member with each portion of said edge corresponding to said slot being essentially equally spaced from said axis when said corresponding edge is closest to said shell;   an outermost one of each second pair of opposing sides of said parallelogram being essentially continuous with said portion of said edge corresponding to a corresponding slot when said corresponding edge is closest to said shell whereby a reduced envelope is obtained.   
     
     
       2. The scroll machine of claim 1 wherein said coupling member has a second pair of keys coacting with said reference member. .Iadd.3. A scroll machine having a shell with an axis containing a reference member, a coupling member and a scroll member with said coupling member coacting with said reference member and said scroll member such that said scroll member is held to an orbiting motion with respect to said reference member wherein: said coupling member is generally ring-shaped and has a center and a first pair of keys on a first side with said first pair of keys being located on a chord spaced from said center and said axis;   said first pair of keys each having a pair of opposing sides which are parallel to said chord and of generally equal length;   said scroll member having a pair of slots parallel to said chord for receiving said first pair of keys and coacting therewith;   each slot of said pair of slots extending to an outer edge of said scroll member with each portion of said edge corresponding to said slot being essentially equally spaced from said axis when said corresponding edge is closest to said shell;   an outermost one of a second pair of sides of each of said first pair of keys being essentially continuous with said portion of said edge corresponding to a corresponding slot when said corresponding edge is closest to said shell whereby a reduced envelope is obtained.   
     
     
        .Iaddend..Iadd.4.  The scroll machine of claim 3 wherein said coupling member has a second pair of keys coacting with said reference member. .Iaddend.