Assymetrically shaped thread forming screw and method of making same
US4534690A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 26, 1983 |
| Grant date | Aug 13, 1985 |
| Priority date | — |
| Expiry date | Oct 26, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S411/03
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A thread forming screw made from a blank which has a tip with an assymetrical cross-section comprised of two oppositely disposed inner surfaces which gradually merge with two oppositely disposed outer surfaces. The inner surfaces may be arcuate or generally flat or a combination thereof. The inner and outer surfaces are generally parallel to each other and to the axis of the screw so that, when rolled, the tip has generally fully formed sharp crested threads which gradually deform workpiece material upon insertion and axially advancing rotation in a bore. The reduced frictional contact is achieved because of substantial unthreaded portions on the inner surfaces. Improved gripping action results from the formation of full threads which extend substantially the full length of the fastener.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.