在一个手动变速器里，当你操纵换挡杆从一个档位到另一个档位时，齿轮沿轴向滑动，使大小不同的齿轮进行啮合从而满足不同的传动比的需要。
In a manual transmission, gears slide along shafts as you move the shift lever from one position to another, engaging various sized gears as required in order to provide the correct gear ratio,.
主轴的进能量和转速是通过选速杆使主轴箱中的适当齿轮相啮合而控制的。
Spindle feeds and speeds are controlled by selector levers which engage the proper gears in the drill head.
阀杆：阀杆与轭架有很长的啮合段，有助于阀座密封的精确对准。
Stem: Stem has long engagement with yoke bushing for accurate seating.
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