| 摘要 |
A device for switching between film-advancing and film-rewinding operations of a movie projector, having a main shaft included in the film-driving means, comprises respective wheels secured to rotate with the supply reel-mounting spindle and the takeup reel-mounting spindle. A support is slidably mounted between these wheels, and carries a pair of pulleys rotatably mounted at respective opposite ends thereof and each adjacent a respective wheel. A drive pulley is mounted on the main shaft for rotation therewith, and an endless belt is trained around the drive pulley and the two pulleys on the support. The direction of tension in the belt changes in accordance with the direction of rotation of the main shaft, to shift the support in the direction of the tension to effect driving of a respective spindle wheel by the belt through rotation of the adjacent pulley. A reversing wheel is rotatably mounted between one spindle wheel and its associated pulley. Either the takeup reel or the supply reel is selected automatically for driving in response to the direction of rotation of the main shaft.
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