| 摘要 |
<p>A document copying machine has a driven input shaft, and an output shaft connected to a document advance mechanism. A pair of driving elements transmits a first desired speed to the output shaft and comprises a first part which is mounted on the input shaft and a second part coupled to the first part and mounted on the output shaft through a first free wheel clutch which is normally engaged. A pair of supplementary driving elements transmits a second desired speed to the output shaft, this speed being faster than the first, and comprises third and fourth elements mounted similarly to the first and second elements, with a second free wheel clutch to selectively disconnect the fourth element from the output shaft, the result of which is that the output shaft speed is controlled by the pair of driving elements transmitting the highest speed and having an engaged clutch.</p> |
