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US 5,015,134 AGranted
Tapping screw
AssigneeYamaki Sangyo Co., Ltd.
InventorIsamu Gotoh
Life of this patent
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Abstract
A tapping screw having a shank having a head and a tapered tip portion. The shank is formed on its peripheral surface with threads. First and second drill edges are formed on the tapered portion and on the intermediate portion between the head and an tapered portion, respectively, so as to be independent of the threads. The first drill edge has a maximum diameter smaller than that of the threads in the rear thereof and the second one has a maximum diameter equal to or larger than that of the threads on the main portion of the shank.
Claims12
A tapping screw comprising:
- a shank having a front portion including a tapered portion at a front tip thereof and a rear portion;
- a substantially pyramidically shaped head integrally connected with a rear end of said shank, said head having a cross sectional area which is substantially equal to a cross sectional area of said shank at a location where said head and said shank connect, said cross sectional area of said head gradually increasing toward a rear end of said head;
- a first drill edge formed on an outer peripheral surface of said front portion of said shank;
- and
- helical threads formed along said shank on an outer peripheral surface thereof with threads formed rearwardly of said first drill edge having a maximum diameter which is smaller than a maximum diameter of said first drill edge.
2 more elements
Dependencies are inferred from the claim text.