Method and apparatus for fastener tensioning
US4106176A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1977 |
| Grant date | Aug 15, 1978 |
| Priority date | — |
| Expiry date | Apr 6, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49767
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A fastener tensioning method and apparatus for obtaining a desired degree of tension in a fastener. The embodiment of this invention described utilizes the slope of the change in torque per change in rotation gradient to predict a rotation starting point independent of the rotation that occured in the torquing cycle up to the point of establishing a constant gradient. In the constant slope or gradient area of the torque rotation curve, rotation is considered linearly proportional to the tension in the fastener. A prescribed additional rotation is applied to the fastener utilizing the threads as a micrometer device for stretching the bolt to achieve the desired tension or fastener strain level. With appropriate system monitoring such as the total rotation, the maximum torque applied, the gradient slope, etc., the system can be adapted to inspect the fastener for applied tension as well as accurately control tension level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.