Self-attaching female fasteners, method of forming same and strip of interconnected fasteners

摘要

A method of forming pierce and clinch nuts by rolling a section having the desired cross-section, punching equally spaced bores through the central pilot portion and then punching configured openings through the central pilot portion having convex arcuate surfaces and eliminating sharp corners. The strip of interconnected self-attaching fasteners may be installed directly from the strip in a panel, fed in bulk or separate fasteners interconnected by frangible connectors. The resultant self-attaching nut includes a central pilot portion having a bore through the top face, integral flange portions extending from opposed sides and the pilot portion includes convex arcuate faces reducing or eliminating stress cracking and propagation of stress cracks.