Tightening system for blind fasteners
US4163311A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 28, 1977 |
| Grant date | Aug 7, 1979 |
| Priority date | — |
| Expiry date | Feb 28, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49766
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A tightening and control system is disclosed for automatically tightening a blind fastener assembly to a desired tightened condition in a workpiece, where the assembly is of the type which exhibits more than one installation region on a graph of two tightening characteristics during a complete tightening cycle. Typical of such assemblies are the types which first form an outwardly flared bulb adjacent the blindside surface of a workpiece and thereafter are tightened against the blindside surface to a predetermined clamp load condition. Such fasteners typically exhibit a curve of two related input tightening characteristics, such as torque and rotation, torque and time, or force and stroke. Each curve has a bulb forming region characterized by a generally linear portion followed by a marked drop off in the slope, an intermediate region, and a tightening region having a somewhat similar shape to the bulb forming region. Apparatus is generally disclosed for determining the gradient of the curve through which the assembly is being tightened, determining when a first condition indicative of having formed the bulb has occurred, and thereafter determining when the tightening should be dis…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.