Thread tapping screw
US5061135A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 28, 1990 |
| Grant date | Oct 29, 1991 |
| Priority date | — |
| Expiry date | Aug 28, 2010 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16B25/0021
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A threaded fastener is presented of the thread-forming type, wherein there is defined, during driving thereof relative to a workpiece a combination of force couples and a resultant moment of force couples to develop material flow of the workpiece material about the threads to give face contact between the mating threads of the fastener and threads formed in the workpiece thereby for improved loading. The threaded fastener comprises a threaded body portion defining an axis and a driver head portion, and including a thread profile in axial cross-section having a plurality of zones including a first zone comprising a trailing thread face with respect to the direction of advancement of the fastener into the workpiece, which trailing thread face defines a first angle relative to the axis of the body portion and a second zone comprising a radiused forward thread face which defines a predetermined radius of curvature, such that the material of the workpiece is induced to flow, during thread forming, generally radially inwardly and forwardly with respect to the direction of advancement of the fastener relative to the workpiece toward the trailing angled face for increased surface contact t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.