Patent ID: 8690693

Claim:
A method for the manufacture of hollow body elements ( 200 ) for attachment to a sheet metal component ( 280 ), the hollow body elements having an at least substantially square or rectangular external outline ( 202 ) obtained by cutting individual elements by length from a section present in the form of a bar section ( 1 ) or of a coil after prior piercing of holes ( 204 ) into the section by using a progressive tool ( 10 ) having a plurality of working stations (A, B and D; B and D) in which respective operations are carried out, wherein the following steps are carried out: a) in a first step, starting from a section ( 1 ) of rectangular cross-section, carrying out an upsetting process which leads to a cylindrical recess ( 208 ) having a first base ( 214 ) at a first broad side ( 2 ) of the section and to a hollow cylindrical projection ( 210 ) having a second base ( 216 ) and forming a rivet section ( 210 ′) at a second broad side ( 3 ) of the section lying opposite to the first broad side ( 2 ), with the projection being surrounded by a ring recess ( 212 ), the ring recess including a portion having a surface substantially parallel with the second broad side and wherein the hollow cylindrical projection has a substantially constant diameter from its distal end to the recess, b) in a second step piercing or punching out a web ( 218 ) remaining between the first base ( 214 ) and the second base ( 216 ) to form a through-going hole ( 204 ), with an internal diameter of said through-going hole ( 204 ) being less than an internal diameter of said hollow cylindrical projection ( 210 ), c) in a last step separating the hollow body elements ( 200 ) from the section.