Constant velocity coupling

A constant velocity joint comprising first and second couplings wherein

• the second coupling is disposed concentrically around the first coupling, each coupling comprising an inner member, an outer annular member and an intermediate annular member between the inner and outer members;
• the members of both couplings are disposed around a common first axis and having a common centre on the common first axis;
• the outer annular member of the first coupling is also the inner member of the second coupling thereby being a common annular member of both the first and second couplings;
• the inner member of the first coupling has an outer spherical periphery and the intermediate member of the first coupling has an inner periphery in which the outer periphery of the inner member of the first coupling is received;
• the intermediate member of the first coupling has an outer spherical periphery and the common annular member has an inner periphery in which the outer periphery of the intermediate second member is received;
• the common annular member has an outer spherical periphery and the intermediate annular member of the second coupling has an inner periphery in which the outer periphery of the common annular member is received;
• the intermediate annular member of the second coupling has an outer spherical periphery and the outer annular member of the second coupling has an inner periphery in which the outer periphery of the intermediate annular member of the second coupling is received;
• the outer peripheries and the inner peripheries being concentric about the common centre and complementary to one another;
• the intermediate annular member of the each coupling is constrained by a first pair of opposed axles to rotate with respect to the inner annular member of the coupling on a first axis perpendicular to the common axis and by a second pair of opposed axles with respect to the outer member of the coupling on a second axis perpendicular to both the common and the first axis;
• and
• wherein the first axis of the outer coupling is the same as the second axis of the inner coupling and the outer member of the second coupling is constrained to rotate angularly in respect of the common member in a way that is the mirror image of the rotation of the inner member of the first coupling with respect to the common member.