Mechanical pencil capable of automatically propelling successive lengths

Abstract

A mechanical pencil has a body with a lead storage chamber defined therein for housing spare lengths of lead, and a tubular lead guide receiving a length of lead and coaxially mounted in the body so as to partly protrude outwardly from its writing end. During writing or marking, the lead guide gradually retracts into the body against the force of a return spring with the wear of the lead received therein and, when the pencil is moved off the writing surface, it is held in place by a locking mechanism until a preselected wear point is reached, then it is sprung back to its normal position. Disposed intermediate the lead storage chamber and the lead guide, a chuck coacts with an internally tapered socket for gripping the lead against displacement away from the writing end of the body. A chuck opener member is coupled to the lead guide in order to hold the chuck open when the lead guide is in the normal position, in order to assure the uninterrupted delivery of the successive lengths of lead from the lead storage chamber into the lead guide.