Head adjustment mechanism

摘要

A head adjustment mechanism comprises an adjustment screw having two male threaded sections cut in the same direction but at different pitches. The adjustment screw has an upper end portion in screw engagement with the upper portion of the head mount and a lower end portion put in screw engagement with the base member. Thus, with one rotation of the adjustment screw the head supported by the upper portion of the head mount is vertically displaced to an extend corresponding to the difference of the pitches of the two thread sections, so that fine adjustment of the head can be obtained.