Roller unlocking sprags

A roller type sprag member consisting of three main elements, an outer roller half section, an inner roller half section, and an assembly-location pin. The sprag locks using roller locking techniques in a manner well known in the case of a three-dimensional (3-D) locking sprag. It unlocks, however, using a roll technique in which the inner and outer roller halves rotate in mutually opposite directions, one clockwise and the other counterclockwise. In the process of rotation, the roller is foreshortened between the distance across the sprag contact surfaces, whereupon it loses its ability to act as a locking sprag and releases.