Mechanical pencil with eccentric means for extending leads from opposite ends thereuf

Claim 1

A WRITING INSTRUMENT COMPRISING: (A) A BARREL HAVING OPENINGS AT OPPOSITE ENDS THEREOF; (B) TIP ELEMENTS EXTENDING LONGITUDINALLY AND CENTRALLY OF THE BARREL, SAID ELEMENTS BEING EXTENDABLE FROM AND RETRACTABLE INTO THE BARREL THROUGH SAID OPENINGS; AND (C) MEANS CARRIED BY THE BARREL AND ENGAGED WITH THE RESPECTIVE TIP ELEMENT FOR EXTENDING AND RETRACTING EACH TIP ELEMENT INDEPENDENTLY OF THE OTHER, SAID MEANS FOR EACH TIP ELEMENT INCLUDING A THREADED ROD ECCENTRIC TO AND HAVING A FIXED CONNECTION TO THE TIP, A PINION HAVING A THREADED CENTER OPENING ENGAGING THE ROD TO SHIFT THE ROD LONGITUDINALLY RESPONSIVE TO ROTATION OF THE PINION, AND A DRIVE RING ROTATABLY MOUNTED ON THE BARREL AND HAVING INTERNAL RING GEAR TEETH MESHING WITH THE PINION FOR ROTATING THE SAME RESPONSIVE TO ROTATION OF THE DRIVE RING, SAID BARREL INCLUDING A TRANSVERSE PARTITION HAVING BEARING OPENINGS IN WHICH SAID RODS ARE JOURNALLED.