Patent ID: 7387575
Filing Date: 2008-06-17
Classification: B21D,B21K,B23P,F16B,Y10T

Abstract:
1. Method for the manufacture of hollow body elements for attachment to sheet metal components said hollow body elements having an at least substantially square or rectangular outline and being manufactured by cutting individual elements from a section having a substantially rectangular cross section with first and second opposite broad sides and present in the form of a profiled bar or a coil after prior punching of respective holes into the section and optionally with subsequent formation of a thread cylinder, wherein, prior to the punching of holes in the section, an upsetting process is carried out using an upsetting stamp at said first broad side of said section and an upsetting die at said second broad side of said section in order to produce by material flow a cylindrical recess at said first broad side and a cylindrical projection at said second broad side and coaxial to said cylindrical recess at said first broad side, wherein the upsetting process is directly followed by said hole punching operation in which the section is holed in the region between said cylindrical recess and said cylindrical projection by means of a hole punch and wherein the diameter of said upsetting punch is selected in the region of its end which carries out the upsetting so that it corresponds at least substantially to the diameter of said hole punch.