Disposable propel-repel pencil

摘要

A mechanical pencil is disclosed that includes a barrel with a non-circular internal bore, a helical coil member that is fitted within the bore and attached to an externally positioned driving member, and a lead positioning means or pusher member that is positioned about and threadably engaged with the coil and constrained by the non-circular bore of the barrel for sliding longitudinal movement therein. The lead positioning means or pusher member includes fins that extend through the coil turns and act as a positioning stop for the writing lead and a lead gripping means for propelling and repelling the centrally disposed writing lead upon the manual rotation of the external driving member that is attached to the coil disposed within the barrel.