| 摘要 |
A dual range manual preset timer drives through the first part of its timing range at relatively high speed to give short timings of relatively high accuracy. It drives through the second part of its timing range to low speed to give long timings where high accuracy is not required. The low speed timing gears are always in mesh to insure against hang up. The high speed gear engages at the change over point in the timing range and drives from this point to the off position. A one way drive on the low speed timing gears permits the faster rotation by the high speed gears.
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