Snap-on Tools Corporation

Martin L Barnhill, Iii

William T Pagac

A socket wrench for an hexagonal fastener wherein the clockwise and counterclockwise drive portions of the internal surface configuration of the wrench engage an associated hexagonal fastener with substantially surface to surface contact on each fastener side in close proximity to, but always spaced from, a fastener corner, thereby providing a maximum practical moment arm between wrench and fastener, and yet avoiding deteriorating engagement between the wrench and the fastener corners. The clockwise and counterclockwise drive portions of the wrench occupy the middle about 1/2 of each uniform 60.degree. segment of the wrench opening. The space on the internal surface configuration of the wrench between adjacent pairs of drive portions is relieved just enough to avoid interference with the corners of the fastener, thereby providing a rotational clearance of about 25.degree. with the fastener, the precise angular amount depending on manufacturing tolerances in the wrench and fastener. This extended rotational clearance is particularly advantageous in the field of power driven socket wrenches, especially power driven socket wrenches of the multiple spindle type commonly used in manufacturing operations.

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Union Grove, WI, United States of America

Martin L Barnhill, Iii