| 摘要 |
<p>The mechanism comprises an input shaft journalled to a frame is rotatable about an input axis, over a range of rotational positions, between a forward limit and a reverse limit. An output shaft journalled to the frame is rotatable about an output axis, which is normal to the input axis. Three bevel gears are employed, namely a first gear coupled to the input shaft, a second gear coupled to the input shaft and spaced axially from the first gear, and a third gear coupled to the output shaft. The bevel teeth of the three gears are arranged in peripheral arrays covering cover less than one half of the entire periphery of each gear, so that the bevel teeth of the third gear intermesh only with the bevel teeth of the first gear whenever the input shaft rotates from the reverse limit toward the forward limit, and so that the bevel teeth of the third gear intermesh only with the bevel teeth of the second gear whenever the input shaft rotates from the forward limit toward the reverse limit.</p> |
