US Patent 7165925 Self adjusting, high strength, screw system

A fastener system and method of inserting it, that includes a screw or bolt having two interleaved helical threads, which brackets or forms a groove for a helicoil. The helicoil expands and torques by various means to maintain hold and purchase between the screw coil combination and the substrate into which the screw and helicoil are inserted even when the substrate recedes a significant distance from the screw and helicoil combination. The fastener system includes means for latching the tilt of the coil so as to minimize the constraining forces and optimize the motion of the helicoil, that results in the screw or bolt being pushed into the substrate. The fastener may be actuated after it has been partly or completely turned into the substrate.