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.
Patent No.:
Date of Patent:
Oct. 30, 1990
Filed:
Jun. 05, 1989
George D Hewison, Twyford, GB;
ITW, Ltd., Surrey, GB;
Abstract
A screw threaded method of making fastener particularly intended for use in fastening corrugated sheet material to metal purlins comprises a drilling point (1), a head (2), a first self-tapping screw threaded portion (3) adjacent the drilling point (1), a second screw threaded portion (4) adjacent the head (2), the second screw threaded portion (4) having a larger crest diameter than the first screw threaded portion (3), and an unthreaded portion (5) extending between the first and second screw threaded portions. The diameter of the part of the fastener carrying the second screw threaded portion (4) is generally larger than that carrying the first screw threaded portion 3 and the fastener also includes a transition portion (6) between its portions of smaller and larger diameter, and in particular, interposed between the trailing edge portion of the first screw threaded portion (3) and the leading edge portion of the unthreaded portion (5). The transition portion (6) includes forming portions (8 FIG. 4) projecting outwardly from the axis of the fastener no further than the diameter of the larger diameter portion. The forming portion (8) in use, enlarge the diameter of a hole drilled within the sheet material by mean of the drilling point (1) so as to allow passage of the larger diameter portion of the fastener through the sheet material. Such a fastener is formed by mean of a forward extrusion step which reduces its diameter and which, simultaneously, forms the forming portions (8) upon the transition (6) portion.