Bearing assembly for a downhole motor

An improvement is a bearing assembly for a downhole motor, the bearing assembly consisting of a cylindrical housing having an interior surface, a cylindrical inner mandrel having an exterior surface telescopically received within the housing, bearing means disposed between the interior surface of the housing and the exterior surface of the inner mandrel thereby facilitating relative rotation of the housing and inner mandrel while bearing axial and radial loading, the improvement comprising:

• a. a plurality of notches in one of the exterior surface of the inner mandrel and the interior surface of the housing, the notches being upwardly inclined from a base;
• and
• b. a plurality of pins disposed between the exterior surface of the inner mandrel and the interior surface of the housing, the depth of the base of each notch exceeding the diameter of the pins, biasing means being provided between each of the pins and the base of each of the notches to exert a forcer biasing the pins up the incline of the notch, such that the pins travel toward the base of the notch where the pins can rotate freely upon relative rotation of the inner mandrel and housing in the first direction and the pins travel up the incline of the notches until the pins become wedged between the interior surface of the housing and the exterior surface of the inner mandrel upon the relative rotation of the inner mandrel and the housing in the second direction, thereby preventing relative rotation of the inner mandrel and the housing in the second direction.