| 摘要 |
An antenna rod, which is extendible and retractable, is moved up and down by a cable with a rack, and the cable is moved with rotation of a pinion gear. The rotational force of a DC motor is transferred to the pinion gear by a route of a worm, a worm wheel, gears, a damper gear, and a damper. The damper is a coil of resilient metal wire, and both ends of the coiled wire, respectively, engage stopping members, which are provided at the center portions of the damper gear and the pinion gear. When the pinion gear is at a standstill, the rotational energy of the damper gear is accumulated in the damper. The motor is rotated under control of a control circuit in response to the operation of a switch. The drive current for the motor is shut off by a detecting signal from a lock detector during the course of accumulating the rotational energy by the damper. The lead angle of the teeth of the worm is large so that the rotational energy stored in the damper is transferred to the motor. |
