Panel-aligning fastener
Panel-fastening systems rely on a combination of oversized structural holes and nut-element float to accommodate panel removal and installation. Improvements in positional tolerances of tooling used to produce interchangeable panels, makes a new Panel Aligning Fastener System (PAFS) feasible.
PAFS differs from common panel fastening systems in that the access panel and its mating structure are treated as a stiff-spring system in which each fastener loads/unloads the spring system a small amount. With PAFS "pinning'' panels in place, it should be possible to design and manufacture improved, lighter weight, more efficient structure using fewer fasteners. Other advantages:
All male fasteners for a given panel can be identical, regardless of substructure thickness
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The fastening system eliminates bending moment failures in the threads
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Receptacle has no moving parts for high reliability
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Improved fastener flushness
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Improved fuel sealing (gasket chafing eliminated)
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Inherent low cost
| Panel hole misaligned with structure hole | With > 3 threads engaged, fastener becomes a jackscrew | Fastener chamfer engages receptacle barrel | Major diameter of bolt moves into the shear plane |
Jim Landgrebe, Lockheed Martin Tactical Aircraft Systems, MZ 4266, Box 748, Fort Worth, TX 76101; (817) 763-2113.