The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Mar. 30, 2004

Filed:

Oct. 03, 2002
Applicant:
Inventors:

Dennis O. Boyer, Newport, RI (US);

Alan Pritchard, Almeria, ES;

Assignee:

Conti Fasteners AG, Baar, CH;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B21H 3/02 ;
U.S. Cl.
CPC ...
B21H 3/02 ;
Abstract

A headed multi-lobed blank, method of manufacturing a self-tapping screw from the blank, and resulting multi-lobed self-tapping screw for joining thin workpieces provides desirable thread-forming characteristics at the conical tip and body portions, and improved resistance to vibrational loosening near the head. The resulting screw, obtained from the blank and method, incorporates a threaded tapered root portion between the screw head and body portion having a cross section that varies from nearly circular in the area adjacent to the underside of the head to a maximum out-of-round (or lobular) cross section at the intersection of the tapered root portion and the screw body. This shape, to combined with a thread profile outer diameter that remains largely constant from the body portion through the tapered root portion, and a multiple coil (lead thread) shape, ensure more secure holding of the screw in a thin anchor material—with the anchor material extruded axially forward and backward around the root portion.


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