Recessed head screw

Abstract

A modified Phillips-type cruciform recess in a screw or the like, which provides a cling-fit with a driver by causing deflection of the flutes of the driver against the walls of the slot in the recess, comprises a central socket portion and radially extending slots adapted to receive the flutes of a suitable driving tool. Each slot is defined in part by a bottom surface of substantially uniform width which slopes radially inwardly and downwardly along the axis of the screw. The bottom surface joins two opposing surfaces which form the walls of the slot. The pairs of opposite slots in the cruciform pattern are not symmetrically located relative to a plane including the longitudinal axis of the screw, but are offset laterally in opposite directions with respect to such a plane. On insertion of a standard driver into the recess, the flutes of the driver are caused to flex into frictional engagement with the walls of the slots, thereby achieving the desired cling-fit.

Dependencies are inferred from the claim text.