Fastening element

A fastening member for forming a fastener assembly by engagement with a standard externally threaded self-tapping threaded fastener having predetermined outer and pitch diameters, comprising:

• a. a body having a central bore of a diameter substantially greater than said pitch diameter and substantially less than said outer diameter;
• b. a formed elliptical rib spaced from one end of said bore by a distance less than 15 percent of the diameter of said bore;
• c. said elliptical rib extending inwardly toward the axis of said bore for most of the circumference of said bore along an elliptical closed-loop line upon said surface of said bore;
• d. two turning points of reversal in axial direction component in said closed-loop line defining a maximum and minimum in axial extent of said elliptical rib;
• e. a rising rib portion in said elliptical rib extending from said minimum axial extent and a descending rib position extending from said maximum axial extent;
• f. said elliptical rib having at least one void on said closed-loop line;
• g. means including backing material enclosing said bore for preventing significant enlargement of said bore as threads are formed herein by said standard externally threaded fastener;
• and
• h. said bore having an enlarged portion between the end of said bore and said formed rib, said enlarged portion having a diameter greater than said outer diameter;
• whereby said standard externally threaded fastener is aligned with and engages said fastening member readily, and said fastening member will have at least one fully formed thread within said bore and near the surface of said body for maximum holding strength combined with reduced driving torque and radial pressure with only partially formed threads in said central bore beyond said elliptical rib.

A nut-type fastening element for forming a fastener assembly by engagement with an externally threaded self-tapping fastener, comprising:

• a. a solid body having a central threadless cylindrical surface defining a bore and extending through said body;
• b. two ribs each being of substantially elliptical configuration and each protruding radially inwardly into said bore adjacent a different one of the two ends of said bore from locations along a substantially elliptical closed-loop line upon the cylindrical surface of said bore, each of said closed-loop lines having two turning points of reversal in axial direction component in each said closed-loop line, one point which is closed to the adjacent end of said bore defining a maximum turning point in axial extent of said elliptical rib and another point which is diametrically opposed and which is farther away from the adjacent end of said bore defining a minimum turning point in axial extent of said elliptical rib;
• c. each said rib further having at least one void at a location between the maximum and minimum axial extent points along said elliptical closed-loop line;
• d. the thickness of each said rib increasing with the depth of said rib from the adjacent end of said bore;
• e. the diameter of said bore between said two ribs being less than the diameter of said bore between each rib and the adjacent end of said bore;
• f. the outer periphery of said nut-type fastening element being provided with surfaces formed for engagement by a wrench;
• and
• g. means including backing material between said bore and said outer periphery for preventing significant deformation of said surfaces when said externally threaded fastener engages and forms threads in said bore.