| 摘要 |
PURPOSE:To obtain the platen driving apparatus having the good operating performance by providing the larger cut out than a scattering of a stopping position in a gear so that the platen would be rotated step by step in a type writer and the like. CONSTITUTION:When a motor 10 is rotated first, then a work 13 and a worm wheel 22 are engaged, and the worm wheel 22 begins to start, and as soon as this engagement is completed, it is stopped simultaneously. The wheel 22 is in a state that there is no hindrance about a discontinuous engagement with the worm 13 by a control apparatuw with a roller 6 in this time. An electric supply to the motor is stopped simultaneously when it is detected that the engagement is completed by a detecting apparatus 19. The stopping position of the wheel 22 scatters at this time, but it is rotated step by step inan accurate angle, if a range of the scattering is set withing a range of the cut of the worm 13. Therefore, the wheel is rotated by one tooth with one rotation of the worm, ratchet teeth 3 are engaged by the roller positively, and the platen 1 can be stopped in a prescribed angle. |
