Sk Hand Tool Corporation

Steven C Simpson

Warren W Weible

A stronger screwdriver blade is disclosed which is particularly effective for driving round-headed screws. The screwdriver blade has an elongate shank with a tapered end extending from the shank and terminating in a tip. The tip has a straight edge perpendicular to the shank and has a predetermined length and thickness, with side edges extending back toward the shank from ends of the end edge. The tip has substantially parallel, planar sides extending back toward the shank from the end edge to inner edges which, at the side edges, are spaced a distance from the end edge which is approximately equal to the thickness of the end edge. The inner edges are curved with the planar sides being from one and one-half to three and one-half times as wide at central portions as at end portions. From the inner edges, opposite side surfaces of the tapered end extend abruptly outwardly in a direction toward the shank so that the blade tip is thicker at high stress areas thereof.

Screwdriver blade with curved tip

A screwdriver blade is provided which has greater resistance to failure. The screwdriver blade includes an elongate shank with a tapered end extending from the shank and terminating in a tip. The tip has a straight edge perpendicular to the shank and is of a predetermined thickness, with parallel, planar sides extending back from the edge a distance which is approximately equal to the thickness of the edge. Opposite surfaces of the blade end then extend abruptly outwardly in a direction toward the shank, each at an angle of approximately fifteen degrees to an axis of the blade. An analysis has indicated that the greatest stress in a screwdriver blade occurs at a predetermined distance back from the straight edge of the blade. The new blade is thicker and stronger at the areas where the greatest stress occurs.

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Napoleon, OH, United States of America

Steven C Simpson