Thread forming nut with locking portion

A fastening nut for securing a molded component such as a bumper rub strip to a mounting surface, as for example, an automobile bumper, wherein said molded component includes an unthreaded stud, of a given diameter "B" and which will extend through an aperture in said mounting surface, said fastening nut comprising:

• A nut body having a central through bore, said bore comprising guide means for providing alignment guidance during insertion of said stud into said bore, said guide means defining an effective minor internal diameter "A,A'";
• and an internal helical thread disposed in said bore axially distinct from said guide means and terminating within said bore adjacent said guide means, said internal helical thread defining a minor thread diameter "D" which is less than the diameter of said stud and said guide means/such that sequentially following the sliding insertion of said stud into said bore past said guide means, said internal helical thread engages said stud periphery and will cold-form a mating external thread therein, said mating external thread being formed by radially outwardly displacing cold-formed stud material, such that said resulting external thread has a major diameter "E" which is greater than the effective internal diameter "A,A'" of said guide means, such that upon retractive movement of the nut from the stud, said guide means will engage said external thread to obstruct and hinder relative retractive moment of the nut from said stud and thereby promotes secured retention of said nut thereon.

A joint structure for securing a studed work piece such as a bumper facia strip to a support member, as for example a bumper, comprising:

• A. a support member having a through passageway therein,
• B. a work piece having an elongate stud projecting through said passageway to expose a projecting end therefrom;
• C. a securing nut comprising:
• 1. a central through bore;
• 2. guide means partially defining said bore and located adjacent a leading aperture of the bore, said guide means defining an inner diameter equal to or slightly larger than the peripheral outer diameter of said stud enabling said guide means to provide aligning guidance in sliding said leading bore aperture onto said projecting end of said stud;
• and
• 3. an helical thread disposed in said bore adjacent a trailing aperture thereof, said thread having a minor diameter smaller than said stud diameter and a major diameter larger than said stud diameter and larger than said inner diameter of said guide means;
• and
• D. said stud and nut being fabricated from respective materials of relative hardness such that, after sliding said guide means onto and along said stud, said thread engages said stud periphery and cold-forms a mating thread therein having having a major diameter of outwardly displaced stud material larger than said inner diameter of said nut guide means so that said mating thread obstructs retraction of said nut guide means from said stud and thereby promotes securement of said joint.

A joint structure for securing a studded work piece such as a bumper facia strip to a support member, as for example, a bumper, comprising:

• A. a support member having a through passageway therein,
• B. a work piece having an elongate stud projecting through said passageway to expose a projecting end therefrom;
• C. a securing nut comprising:
• 1. a central through bore;
• 2. guide means radially projecting in said bore, said guide means comprising at least a partial annulus having an inner diameter equal to or slightly larger than the peripheral outer diameter of said stud enabling said guide means to provide aligning guidance during sliding insertion of stud into said bore;
• and
• 3. internal thread means disposed in said bore, said internal thread means having a crest diameter smaller than said stud diameter and smaller than said inner diameter of said guide means;
• and
• D. said stud and nut being fabricated from respective materials of relative hardness such that, after sliding said guide means onto and along said stud, said internal thread means engages said stud periphery and cold-forms a mating thread configuration therein having a maximum outer diameter of outwardly displaced stud material larger than said inner diameter of said nut guide means so that said mating thread configuration obstruct retraction of said nut guide means from said stud and thereby promotes securement of said joint.