Powered six-way seat adjustor and mechanisms therefor

For use in a vehicle seat adjuster, for use in conjunction with a lead screw, a load bearing structural assembly, the assembly comprising a threaded lead screw having a central axis, the lead screw having mounting means and anchor means affixed to one end thereof;

• the lead screw having mounted thereon a first drive nut having an opening therethrough, the first drive nut having a predetermined load bearing capacity, the circumference of the opening of the first drive nut having compatible threading with the lead screw;
• the structural assembly having a second drive nut having an opening therethrough affixed to the first drive nut, the second nut having a much greater predetermined load bearing capacity than the first drive nut and having threading disposed about the circumference of the opening compatible with the lead screw;
• the structural assembly having a collet having an interior and exterior, the collet in communication with the exterior surface of the second drive nut upon the interior of the collet, having an opening therethrough, having transmission means affixed to the first drive nut and the collet, whereby the first drive nut is driven by the rotation of the lead screw when the first drive nut is subjected to loads less than or equal to its predetermined load bearing capacity and the second drive nut does not interfere with the movement of the first drive nut when the first drive nut is subjected to loads less than or equal to its predetermined load bearing capacity thereby driving the transmission means in a predetermined direction;
• whereby when the transmission means subjects a load upon the first drive nut in a direction along or parallel to the central axis of the lead screw, such load being greater than the predetermined load bearing capacity of the first drive nut, causing the first nut to fail, such load will also be subjected upon the collet which will further capture the second drive nut within the opening at the interior of the collet and force the second drive nut to clamp down on the lead screw sufficiently to prevent rotation of the lead screw and to pass the load from the transmission means to the collet, from the collet to the second drive nut, from the second drive nut to the lead screw, and from the lead screw to the anchor means, and from the anchor means to the mounting means, thereby resolving the axial loading of the lead screw, preferably the transmission means being a bracket affixed to a seat track.