A method of making shell segments for expansion bolts, apparatus for carrying out the method and expansion bolt comprising shell segments made by the method

摘要

A system for manufacturing expansion bolts, in particular their shells, which comprise a plurality of generally channel-shaped segments. A continuous trip of metal having substantially the width and the channel shape of the shell segments to be produced, is subjected to cold deformation following manufacture of an intermediate product with at least locally a smaller size than the finished product, this size difference being judicially selected so as to necessitate a certain amount of cold deformation resulting in a local increase of material strength.