Screw threaded fastener
US4878793A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 8, 1988 |
| Grant date | Nov 7, 1989 |
| Priority date | — |
| Expiry date | Sep 8, 2008 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16B25/103
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A screw threaded 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) projecting outwardly from the axis of the fastener no further than the diameter of the larger diameter portion. The forming portions (8) in use, enlarge the diameter of a hole drilled within the sheet mate…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.