| 摘要 |
PURPOSE:To attain simply and surely the control with high accuracy by providing two rack members and two transmission gear systems driving a loading mechanism and a clamper mechanism and cutting the tooth tip at the meshing start position of the two rack members so as to prevent locking of the two transmission gear systems. CONSTITUTION:The notch part 397 for preventing locking is formed at the vicinity of the tooth root from the root to a prescribed position of the 1st tooth part 393. Then, the notch tooth part 398 for preventing locking due to meshing is formed to the tooth part 393 by cutting the tooth tip of, e.g., two teeth from the root of teeth in an acute angle as shown in hatched lines. When a reducer gear 27 is meshed with the notch tooth part 398 of the tooth part 393 of the moving rack 39 by utilizing the elasticity of the notch part 397, a reducer gear 25 is detached from the tip of a fixed rack 38 almost at the same time. Since the gear part 393 of the moving rack 39 is formed so as to prevent the locking state caused by simultaneous meshing of the reducer gears 25, 27 in the tooth part 393 of the moving rack 39 by means of the elasticity of the notch part 397, overload to a motor 21 is prevented. |
