| 摘要 |
A microtome has first and second shafts at different fixed positions, wherein the first shaft may be rotated by a hand wheel. The shafts carry first and second gear wheels, respectively. A transmission unit couples the two gear wheels to each other so that the second shaft can be driven to rotate by the first shaft, and a shift unit for pivotably shifting the transmission unit between first and second positions. The two shafts rotate in the same direction when the transmission unit is in the first position, and in opposite directions when the transmission unit is in the second position. The transmission unit includes first and second idler gears meshing constantly with each other. The two shafts are coupled by only one of the idler gears when the transmission unit is in the first position, and by both idler gears when the transmission unit is in the second position. |
