| 摘要 |
<p>A retractable mechanical pencil unit 3 and a ball point or rollerball pen unit 3' are assembled in a lower barrel 1 of a writing instrument having an upper barrel 2 which is rotatable in one or two directions relative to the lower barrel and guide 9 around its axis. Cam 8 within said upper barrel of the writing instrument engages with the pen and pencil units to selectively shift them axially into writing position. The upper barrel is shiftable axially relative to said lower barrel by a distance set by rotating sector 12 and stationary cam 12 on the head 16 of guide 9 to operate the lead feed of the mechanical pencil unit when this unit is in its writing position, but the set distance reduces to zero and the upper barrel is axially non-shiftable relative to the lower barrel when the pen unit is in its writing position. <IMAGE></p> |
