Thread forming fastener
US8684646B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 12, 2008 |
| Grant date | Apr 1, 2014 |
| Priority date | — |
| Expiry date | Apr 5, 2032 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16B25/0047
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A thread forming fastener for threading into a nut anchor of a pliable material wherein there is produced during the driving of the fastener a combination of forces that encourages the nut anchor material to flow smoothly and to develop a mating thread in the nut anchor that minimizes stress cracking and radial hoop stress as the mating thread is being formed. The fastener comprises a drive head and a shank extending from the head and having a longitudinal axis, the shank including a core and a thread having a selected axial pitch, a selected thread height and a profile which in axial cross-section includes a leading face, a trailing face and a tip. The leading face is composed of a radially inner concave portion having a first radius and which transitions smoothly to a radially outer convex portion having a second radius, the transition occurring at a point on the common tangent to those portions. The trailing face is composed of a radially inner linear portion which transitions at a selected transition location to a radially outer convex portion having a third radius. The profile also includes a convex blending portion having a fourth radius which blends together the radially out…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.