| 摘要 |
PURPOSE:To attain the titled device capable of sure driving with a simple constitution by providing a rack gear having elasticity along a driving shaft to the side to be supported of a pickup to mesh a worm gear in elastic contact. CONSTITUTION:A notched part 397 for preventing locking due to meshing is formed to the 1st tooth section 393 in the vicinity of the base of teeth from the base to a prescribed position. Then, the tooth part 393 is formed by the notched tooth part 398 for preventing locking due to meshing, having the tooth tip of e.g., two teeth from the base notched in sharp angle as shown by a slant line. Further, when a reducer gear 27 is meshed with the notch tooth part 398 of the tooth part 393 of a moving rack 39 by utilizing the elasticity of the notch part 397, a reducer gear 25 is detached from the tip of the fixed rack 38 almost at the same time. Thus, the locking state caused by simultaneous meshing of the reducer gears 25, 27 is prevented for the tooth part 393 by means of the elasticity of the notch part 397 and overload to a motor 21 is prevented, allowing to save electric power. |
