Automatic pencil apparatus for an automated drafting system

摘要

An automatic pencil apparatus for use with an automated drafting system comprises a gripping mechanism for releasably gripping a lead and comprised of a cylindrical tube, and a collet mounted for longitudinal movement in the tube for gripping and releasing the lead. A driving mechanism including an electromagnet selectively drives the gripping mechanism to actuate the collet and release the lead so that a drawing operation can be carried out. A pneumatic cylinder applies a predetermined constant pressure to the lead while in its released state thereby pressing the lead into contact with a drafting paper under constant pressure so that high quality lines can be drawn throughout consumption of the lead and independent of lead wear.