Flexible drilling motor coupling

A shaft coupler for rotationally and axially connecting two machine members, each of which may rotate about an independent axis with the two axes intersecting at a point within the coupling and deflect an amount that may vary between zero and a preselected angle, the coupling comprising:

• (a) a first member, with a centerline coincident with one of the axes, having attachment means at a first end to attach to one of the machine members, a generally central bore opening toward the second end, a first plurality of jaws peripherally spaced about and extending from said second end some distance along said centerline with first openings therebetween opening radially outward from said first bore, said first bore having a reduced diameter extending some distance from said second end and expanding in diameter to form abutments facing said first end on said jaws and providing an inner opening with a concave spherical surface at the bottom opening toward said second end;
• (b) a second member with a centerline coincident with the other axis, having attachment means at one end to attach to the other of the machine members, a generally central second bore opening toward the other end, a second plurality of jaws peripherally spaced about and extending axially some distance from said other end with second openings therebetween opening radially outward from said second bore;
• (c) a generally cylindrical thrust element with a convex spherical surface forming one end sized to fit said concave surface, a generally cylindrical extension forming the other end, a flange larger than said reduced diameter and smaller than said inner opening situated between said convex surface and said other end, said flange having a plurality of peripherally distributed and axially extending slots to accept axial passage of said reduced diameter which forms the radially inner diameter of said first plurality of jaws;
• (d) securing means to axially secure said thrust element in said second bore when said spherical surfaces are in contact and said element is rotated to juxtapose said slots and said first plurality of openings and after said second member is axially positioned relative to said first member to cause said first and said second plurality of jaws to interdigitate for rotational coupling of said machine members;
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• (e) clearances between opposed surfaces on said members and between said flange and said abutments to permit both said first and second members to rotate about axes that intersect in the vicinity of the center of radius of said spherical surfaces and deflect an amount up to said preselected amount.