| 摘要 |
<p>A pen (2) has a pen tip (18) and associated cartridge (24) that are automatically extended and retracted when an actuator switch (12, 20) is pressed by the user. A D.C. motor (28) is coupled to a gear reduction assembly (26) inside the pen housing to cause an attached threaded sleeve (8) to rotate within a stationary nut (10) to drive the tip and cartridge assembly forward or backward depending on the polarity of the electrical supply to the motor. Limit switches (30, 34) cause the tip and cartridge assembly to stop at proper locations. An alternate embodiment utilizes non-moving, skin conductive switches (50, 52) to operate the assembly.</p> |
