Patent attributes
Example aspects of the present invention comprise two concentric rings, the rings movable relative to each other and defining a clearance between them for receiving at least one ball. The first ring is a coupling member, the second ring is a tubular slipper with a friction surface on the far side of the clearance, and the ball contacts the coupling member to the tubular slipper. At least one ring has a first recess with side walls for receiving the least one ball, and the friction surface is configured to displace in a radial direction when the at least one ball is axially aligned with the first recess and forced to run up the side walls by rotating the rings relative to one another. In an example embodiment of the invention, the first recess is a calotte.
