Drawing pen nib construction - has peripheral grooves in sleeve joined by axial grooves to form spiral vent passage

摘要

The drawing nib is for an ink-filled pen; it has a drop weight guided in the sleeve and equipped with a cleaning wire. A locking sleeve for the weight fits in this sleeve, and a vent system for the ink chamber incorporates peripheral and axial grooves in the external screw thread of this sleeve and passages in the locking sleeve. Each peripheral groove (20) is enclosed by a rib (24), while an axial connecting groove (22) runs between the peripheral groove ends. These axial grooves extend in opposite directions from the ends of adjacent peripheral ones, so as to form a single spiral venting passage.