Patent ID: 7329191

Claim:
A method for manufacturing hollow body fastener elements for attachment to components normally consisting of sheet metal, said hollow body elements having an at least substantially square or rectangular outer periphery by cutting individual elements by length from a section present in the form of a bar section or a coil following a prior piercing operation to punch respective apertures at respective positions in the section and optionally after subsequent formation of a thread cylinder, wherein an upsetting process is carried out prior to or after said piercing operation at each said respective position in order to produce by material flow a cylindrical projection concentric to each said aperture at a side of the section confronting the component in use, wherein a section is selected which is of at least substantially rectangular cross-section with two bars at said side confronting the component, said bars being spaced apart and extending parallel to longitudinal sides of the section, being at least substantially rectangular in cross-section and each having at an inner side an inclined flank which forms an undercut.