Method for the production of hollow elements, hollow element, assembly piece, and follow-on composite tool for carrying out said method

Hollow body element for attachment to a component normally comprising sheet metal, the hollow body element comprising:

• one of an at least substantially square and rectangular outline with a first broad side and a second broad side forming a sheet metal contact surface, a piercing section, which projects beyond the second broad side and has an undercut and is surrounded by a ring recess having a conical outer surface in the second broad side, wherein the conical outer surface merges into the second broad side,
• an aperture, which extends from the first broad side through the piercing section, with the aperture optionally having a thread cylinder, and features providing security against rotation are formed one of outwardly at the hollow cylindrical projection and inwardly in a region of the ring recess around the hollow cylindrical projection.

Hollow body element for attachment to a component normally comprising sheet metal, the hollow body element comprising:

• an at least substantially polygon outline with a first broad side and a second broad side,
• a piercing section, which projects beyond the second broad side and has an undercut and is surrounded by a ring recess in the second broad side, and an aperture, which extends from the first broad side through the piercing section, with the aperture optionally having a thread cylinder,
• wherein the ring recess is polygonal in plan view and is provided with a plurality of surfaces set obliquely to a central longitudinal axis of the hollow body element, which are inclined away from the central longitudinal axis of the hollow body element when viewed in a direction from the first broad side to the second broad side.

Progressive tool for the manufacture of hollow body elements such as nut elements for attachment to components normally comprising sheet metal, in particular for the manufacture of hollow body elements having an at least substantially polygon outline by cutting individual elements to length from a section present in the form of one of a profile bar and a coil after prior piercing of apertures into the section, optionally with subsequent formation of a thread cylinder using a progressive tool with a plurality of working stations, wherein in each case two operations are simultaneously carried out for each stroke of the progressive tool in each working station for the section or for a plurality of sections arranged alongside one another, wherein an upsetting process is carried out in a first working station for the manufacture of a cylindrical projection at the second broad side, a piercing process is carried out in a second working station by means of a cylindrical piercing punch, a flattening process is carried out in a third working station for the manufacture of an undercut of the cylindrical projection and the separation of in each case two hollow body elements from the section or from each section is carried out in a fourth working station by means of the cut-off punch.