Patent ID: 7318691
Filing Date: 2008-01-15
Classification: B23P,Y10T

Abstract:
1. A tool, comprising: an elongate body having a central longitudinal axis, said body having an upper end and a lower end spaced along the axis and a sidewall defining an interior chamber between said ends; two parallel elongate slits defined in said sidewall on opposing sides of said axis; a neck section integrally formed at said upper end of said elongate body wherein said neck section is attachable to a rotational machine to rotate said body around the axis; a bit holder rotationally mounted within said interior chamber and configured to retain a bit extending outwardly from said lower end of said body along the axis; a driver mechanism situated within said hollow interior chamber and engaged to transmit rotational force imparted to said body to said bit holder, wherein said driver mechanism includes a cylindrical plate having an internal diameter rotationally seated within the internal diameter of said interior chamber and a locking pin with a central portion passing through said cylindrical plate and opposing ends received in said longitudinal slits; a breakaway mechanism arranged between said driver mechanism and said bit holder wherein said breakaway mechanism rotationally disengages said driver mechanism from said bit holder when the transmitted rotational force exceeds a preset torque threshold and wherein during said disengagement said locking pin opposing ends reciprocate within said longitudinal slits to increase the spacing between said cylindrical plate and said bit holder; a torque threshold adjustment mechanism, wherein said mechanism is adjustable to compress said driver mechanism against said bit holder along the length of said interior chamber to preset the torque threshold; and, a set screw engaged between an internal bore through said upper end and against a top surface of said torque threshold adjustment mechanism, wherein said set screw is adjustable to adjust said torque threshold adjustment mechanism.