Patent ID: 6792838
Filing Date: 2004-09-21
Classification: B25B,F16B

Abstract:
A fastener system comprising a plurality of ranges of size of threaded fastener, each fastener having a head provided with a recess to receive a tool to rotatingly drive the fastener, each recess having a floor, and wherein:in each range of sizes, the largest size of fastener has a recess comprising a plurality of driving recess tiers of reducing size superimposed on one another, each recess tier having sides, which sides are substantially parallel a long axis of the fastener and define a polygon in section, each recess tier having a base, which base is the junction with the adjacent smaller tier recess, or with the floor of the recess in the case of the smallest recess tier; between two adjacent size ranges, there is a common recess tier, being the largest recess tier of the recess of the smaller size range and the smallest recess tier of the recess of the larger size range, which common recess tier is the same section in each range; and the depth from the base of the largest recess tier to the floor of the smallest recess in the smaller size range is less than the depth of the smallest recess tier in the larger size range.