Automatic pencil

Claim 1

A MECHANICAL PENCIL INCLUDING IN COMBINATION, A TUBULAR HOUSING HAVING AN OPEN END AND A BORE EXTENDING SUBSTANTIALLY THE ENTIRE LENGTH THEREOF, A THREADED SCREW IN THE HOUSING BORE HAVING A HEAD ON ONE END THEREOF SHAPED TO CORRESPOND TO AT LEAST A PORTION OF THE LENGTH OF THE HOUSING BORE AND HAVING MARKING-MEMBER-CONNECTING MEANS AT THE OTHER END THEREOF, WITH SAID SCREW MOVING BETWEEN TWO AXIAL LIMITING POSITIONS IN THE HOUSING AND MAINTAINED AGAINST ROTATION IN THE HOUSING BORE, A MARKING MEMBER HAVING A SUPPORT THEREWITH ADAPTED FOR RELEASABLE CONNECTION WITH THE MARKING-MEMBERCONNECTING MEANS ON THE SCREW AND BEING AXIALLY MOVABLE WITH THE SCREW, A SINGLE MEMBER IN SAID HOUSING BORE FOR BOTH ENCASING THE MARKING MEMBER FOR ITS AXIAL MOVEMENT AND FOR CONNECTING WITH THE SCREW IN A CONTINUOUS THREADED CONNECTION FOR ITS ENTIRE AXIAL TRAVEL AND AT EACH OF THE TWO AXIAL LIMITING POSITIONS, SAID SINGLE MEMBER HAVING A THREADED SECTION AT ITS INNER END FOR SAID CONNECTION, MEANS LOCKING SAID SINGLE MEMBER IN SAID HOUSING BORE AGAINST ROMOVAL THEREFROM BUT PERMITTING RELATIVE ROTATION BETWEEN SAID HOUSING AND SAID SINGLE MEMBER, WITH SAID SINGLE MEMBER HAVING A PLURALITY OF AXIALLY EXTENDING APERTURES AT SAID THREADED-SECTION END FORMING TRANSVERSELY SPREADABLE RESILIENT PORTIONS AT THAT END WITH A THREADED PORTION ON EACH RESILIENT PORTION, SAID RESILIENT PORTIONS PERMITTING A CORRESPONDING TRANSVERSE SPREADING OF THE THREADED PORTIONS THEREON, SAID HOUSING BORE WALL BEING SPACED AWAY FROM SAID SINGLE-MEMBER RESILIENT PORTIONS A DISTANCE TO PERMIT SAID SPREADING WITHIN SAID BORE, AND WITH SAID SINGLE MEMBER AND SAID RESILIENT PORTIONS THEREON REMAINING IN THE SAME AXIAL LOCKED POSITION WITHIN SAID HOUSING BORE WHEN THE THREADED SCREW IS AT EACH LIMITING AXIAL POSITION AND IN THREADED CONNECTION THEREWITH, BUT WITH THE RESILIENT PORTIONS BEING URGED OUTWARDLY WITH CONTINUED RELATIVE ROTATION OF THE SINGLE MEMBER AND THE HOUSING BY THE INTERACTION OF THREADS ON THE SCREW AND ON THE RESILIENT PORTIONS SO THAT SLIPPAGE WILL OCCUR BETWEEN THE THREADS AT A SCREW-LIMITING POSITION AND THE SCREW AND THREADED PORTIONS WILL NOT SEPARATE AXIALLY NOR BIND WITH RESPECT TO ONE ANOTHER, SAID MARKING MEMBER BEING DISCONNECTIBLE FROM THE SCREW AND REMOVABLE FROM THE SINGLE MEMBER TO REPLACE A MARKING MEMBER IN THE PENCIL WHILE THE SINGLE MEMBER IS LOCKED IN THE HOUSING.