Abstract A nut member having a relatively smooth walled aperture for receiving a male threaded member, and a pair of radially extending spiral lip portions adjacent the opening to the aperture, which receive the threaded portion of the male member and guide it into the aperture, forming a female thread. The male threaded member may have an unthreaded cylindrical end which has a diameter approximately equal to the diameter of the aperture, which is the pitch diameter of the threads, which prevents inadvertant removal of the male member after it is threadably received through the aperture. The male member may then be partially withdrawn, deforming the crest portions adjacent the cylindrical end of the male member, permanently locking the assembly. The method disclosed herein includes forming the body portion of the unthreaded member including the circular aperture, and forming the spiral lip portions by impacting the end. A mandrel having radial slots may be disposed within the aperture to form the lip portions.
A fastener assembly comprising a nut member and a relatively harder male threaded member, said nut member having an unthreaded generally circular aperture having an open end adapted to receive said male threaded member and having an internal diameter approximately equal to the pitch diameter of said male threaded member, and a pair of opposed radially extending spiral lip portions adjacent said open end of said aperture each extending spirally toward said open end to guide the male threaded member into the circular aperture said spiral lip portions having a spacing therebetween at least as great as the internal diameter of said aperture, and said male threaded member having an unthreaded leading end of a diameter equal to approximately the pitch diameter of the threaded portion and slightly less than the internal diameter of said unthreaded aperture, such that the unthreaded portion cannot be withdrawn through the nut member after threads are formed in the aperture of the nut member by threading the male member thereinto through said open end.
Claim 2
Dependent Claim
170 words
A fastener assembly comprising a nut member and a relatively harder male threaded member, said nut member having an unthreaded generally circular aperture having an open end adapted to receive said male threaded member and having an internal diameter approximately equal to the pitch diameter of said male threaded member, and a pair of opposed radially extending spiral lip portions adjacent said open end of said aperture each extending spirally toward said open end to guide the male threaded member into the circular aperture said spiral lip portions having a spacing therebetween at least as great as the internal diameter of said aperture, and said male threaded member having an unthreaded leading end of a diameter equal to approximately the pitch diameter of the threaded portion and slightly less than the internal diameter of said unthreaded aperture, such that the unthreaded portion cannot be withdrawn through the nut member after threads are formed in the aperture of the nut member by threading the male member thereinto through said open end.
Claim 3
Dependent Claim
44 words
The fastener assembly defined in claim 1, characterized in that said spiral lip portions each extend circumferentially approximately 90* relative to the axis of said aperture with the leading edge of one spiral lip portion adjacent the following edge of the other lip portion.
Claim 4
Dependent Claim
44 words
The fastener assembly defined in claim 2, characterized in that the spiral lip portions are generally C-shaped and extend beyond the axial end of the nut member to be deformed radially inwardly upon engagement to lock the nut member on the male threaded fastener.