Rotary pencil mechanism with protection against excessive rotation

摘要

The rotary pencil mechanism comprises a point part, relatively to which a threaded spindle is rotatable with an inner thread. Within the threaded spindle is arranged a slide in which a writing lead is insertable in the writing point side end, whilst with its other end it engages with a cam in the inner thread of the threaded spindle. Between the threaded spindle and the slide is a guide tube, which is firmly connected with the point part and has a guide groove, through which the cam of the slide engages. The thread (11a) of the inner thread of the threaded spindle (11) evolves at the end turned away from the point part into a cylindrical widening (121b) and inside the guide tube (12) between its end turned away from the point part and the slide (13) a pressure spring (18) is provided.