Abstract: An improved nut is secured to an unthreaded stud which is inserted through a central bore in the nut. The bore includes a guide means which provides alignment guidance during sliding insertion of the stud into the bore. The guide means preferably has an annular configuration with an inner diameter slightly larger than the diameter of the stud so that the initial insertion of the stud does not produce significant frictional resistance. The bore of the nut further includes a helical thread, preferably a single thread turn, which is disposed in the bore axially distinct from the guide means and terminates within the bore adjacent the guide means. The helical thread has a minor diameter smaller than the stud diameter and also projects radially inwardly into the bore further than the guide means. The cold-forms a mating thread impression into the periphery of the stud and the resulting thread impression obstructs any vibrational retraction of the guide means to promote retention of the nut on the stud.

Abstract: There is disclosed a structural joint comprising a workpiece in the form of a section of sheet material and a fastener assembly, wherein the components of said joint are constructed to retain the fastener assembly in mounted relation with respect to the sheet material and confine the fastener against rotation upon the attachment of an additional fastener component thereto. The section of sheet material includes an aperture having a multi-lobular periphery. The fastener assembly includes a head portion and a shank portion extending axially therefrom. The head portion has an end cap section which is of a greater dimension than the sheet material aperture, and an intermediate section extending axially from the cap section and having a multi-lobular peripheral dimension to be received in the multi-lobular aperture formed in the section of sheet material.

Abstract: A self-clinching fastener and method of engagement thereof with an aperture section of sheeted material. The fastener includes a shank portion and an enlarged head, said shank portion having a tapered extruding section thereon of larger diameter than the aperture in said sheet material. The initial assembly steps resulting in said extruding section engaging and deforming a portion of the sheet material about said aperture to resize said aperture to a predetermined diameter, such that said shank will now be closely engaged with the aperture walls, and if desired the effective length of said aperture may be increased by the production of a rimmed hole. Accordingly, upon the further embedding of the fastener head into said sheet material, a portion of said material will be displaced radially inwardly to fill a relatively wide annular groove formed in said fastener shank thereby assuring a firm mechanical interlock.

Abstract: A self-tapping fastener and method of manufacture wherein said fastener is provided with a unique tapping section, in addition to a driving head and an intermediate threaded portion of generally conventional design. The tapping section is defined by a plurality of interrupted thread turns of an asymmetrical configuration. Each turn includes a pair of diametrically opposed lobe portions, with a pair of opposed side portions disposed intermediate said lobes. One said side portion is defined by a complete absence or void of material provided by a gap of controlled dimensions, while the other is provided by a thread form of an incomplete or under-filled configuration. The fastener of the invention is fabricated by rolling a specially designed blank between a pair of standard thread rolling dies.