US 4,060,020 AGranted

Sheet metal screw

AssigneeLeviton Manufacturing Co., Inc.

InventorJohn N. Poliak

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Abstract

A sheet metal mounting screw and method of forming the same is disclosed. The screw is formed from a single flat blank of sheet metal having a generally T-shaped head and a slotted shank or barrel. The shank, when folded, is tubular and has a seam extending along one side, with spaced resilient teeth extending outwardly from opposite sides thereof. The teeth have inclined outer edges arranged in a helical path extending lengthwise around the shank in staggered relation to one other, for engagement with either tapped or untapped openings in a support. The teeth are resilient and permit a push-in insertion of the threaded shank in the helically threaded opening. The T-shaped head is formed integrally with the shank and contains a tool-receiving slot, which permits the screw to be turned angularly in tightening or removing the screw. In forming the screw, a T-shaped blank is cut from a sheet of resilient metal. The spaced teeth are cut from the shank and are bent outwardly. Upper ends of the teeth are inclined and are arranged in a helical path around the shank for engagement with the threaded opening in the support. The shank is rolled into a tubular form with a tapered lower extremity which enters the opening in the support. The T-shaped upper end of the blank is then folded to form the head of the screw with the slot therein extending transversely of the shank. The sides of the T-shaped bend are folded to form supports extending along opposite sides thereof.

Claims1

Dependent claims

A fastener capable of being formed from a blank of sheet material, comprising, in combination:

a fastener body comprising a generally tubular shank portion extending substantially about a longitudinal axis from a shank extremity, said shank portion including a plurality of generally cantilevered projection means extending outwardly from said longitudinal axis, each of said projection means including outer bearing surfaces which join substantially helically extending free edges thereof, said shank portion further including a pair of spaced tongue members integral therewith and spaced from one another, said tongue members extending in generally parallel relationship with respect to said longitudinal axis, and head means integral with said shank portion at a disposition opposite said shank extremity for transmitting both linear driving forces substantially parallel to said longitudinal axis and rotating forces about said longitudinal axis to said shank portion, said head means including external bearing surfaces for receiving said linear driving forces and internal opposing bearing surfaces extending substantially perpendicularly with respect to said external bearing surfaces for cooperatively receiving said rotating forces from a first tool inserted within an opening defined by said internal bearing surfaces, said head means further including substantially polygonal external surfaces capable of being engaged by a second rotating tool, said head portion formed by a plurality of 180.degree. bends of sheet material extending from a web interconnecting said shank and head portions to remote surfaces disposed adjacent said tongue members for preventing rotation of said tongue members.

Dependencies are inferred from the claim text.