Abstract: A unidirectional mechanism slides along guides within a casing against a spring. A recess in one end of the unidirectional mechanism receives the head of an anchor bolt, and a cover on the casing near that end receives a nut on the anchor bolt.Turning the casing in a counterclockwise direction engages the one-way mechanism, turning both the anchor bolt and the nut. When the anchor bolt is secure, the casing is turned clockwise. The one-way mechanism automatically disengages and the nut is turned on the anchor bolt without turning the anchor bolt.