Method of welding capped wheel nut
First Claim
1. The method of forming a capped nut having a nut body with a central threaded aperture and polygonal sides, and a sheet metal cap adapted to at least partially surround the sides, comprising:
- bringing a pair of electrodes into pressured contact with opposed sides of the cap to impose opposed forces between the cap and the nut body,and passing a high current electrical pulse between the electrodes to cause a primary current flow through the contacting areas between the cap the the nut body adjacent the electrodes and through the nut body to cause welding of the cap to the nut body at the areas adjacent the electrodes.
5 Assignments
0 Petitions
Accused Products
Abstract
A steel nut body has its wrench flats covered by a sheet stainless steel sheath that extends over one of the nut ends to form a cap. The surfaces of the wrench flats are formed with ridges that bear against the inner surfaces of the sheath. The sheath is welded to the nut to resist forces exerted during torquing by bringing a pair of electrodes into pressured contact with the sheath on opposed sides of the nut to produce pressure concentrations at the ridges. An extremely short, high current electrical pulse is then passed between the electrodes. The heating produced by the current at the interface between the sheath and the nut body decreases the electrical resistance of this path resulting in primary current flow path between the two interfaces, through the nut body, to produce resistance welds at the inner faces without substantially modifying the metallurgy of the sheath.
22 Citations
25 Claims
-
1. The method of forming a capped nut having a nut body with a central threaded aperture and polygonal sides, and a sheet metal cap adapted to at least partially surround the sides, comprising:
-
bringing a pair of electrodes into pressured contact with opposed sides of the cap to impose opposed forces between the cap and the nut body, and passing a high current electrical pulse between the electrodes to cause a primary current flow through the contacting areas between the cap the the nut body adjacent the electrodes and through the nut body to cause welding of the cap to the nut body at the areas adjacent the electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. The method of welding a sheet metal sheath to a nut body at least partially covered by the sheath, to form a capped wheel nut comprising:
bringing a pair of electrodes into contact with spaced points on the outer surface of the sheath which overlies sections of the nut body and passing a short duration, high current pulse between the electrodes to cause a breakdown of the electrical resistance of the interfaces between the inner surface of the sheath and the contacted areas of the nut body, adjacent the electrodes, to provide a primary current path through these interfaces and the nut body between them resulting in welding of the sheath to the nut body at these interfaces. - View Dependent Claims (10, 11, 12, 13, 14)
-
15. A method of forming a capped nut having a carbon steel nut body with a central threaded aperture and polygonal sides, and a stainless steel sheet metal cap adapted to at least partially surround the sides, comprising:
-
bringing a pair of electrodes into pressured contact only with the opposed polygonal sides of the cap to impose opposed forces between the cap and the nut body, and creating primary current flow through the contacting areas between the cap and the nut body adjacent the electrodes and through the nut body to cause welding of the cap to the nut body at the areas adjacent the electrodes by the exclusive step of passing a high current electrical pulse of short duration between the electrodes. - View Dependent Claims (16, 17, 18, 19)
-
-
20. The method of welding a stainless steel metal sheath to a carbon steel nut body with polygonal sides at least partially covered by the sheath, to form a capped wheel nut comprising:
bringing a pair of electrodes into pressure contact only with diametrically opposed spaced points on the outer surface of the sheath which overlies the polygonal sides of the nut body and passing a short duration, high current pulse between the electrodes to cause a breakdown of the electrical resistance of the interfaces between the inner surface of the sheath and the contacted areas of the nut body, adjacent the electrodes, to provide a primary current path through these interfaces and the nut body between them resulting in welding of the sheath to the nut body at these interfaces without requiring additional apparatus for displacing current through the nut body. - View Dependent Claims (21, 22, 23, 24, 25)
Specification