It is a disc or collar with an irregularly shaped edge, which operates in contact with a rod or lever, and causes it to oscillate, or to move to and fro.

它是一个不规则形的圆碟或圆环，和一个杆或棒连接运作，使它上下或往来摆动。

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It is a disc or collar with an irregularly shaped edge, which operates in contact with a rod or lever, and causes it to oscillate, or to move to and fro.

它是一个不规则形的圆碟或圆环，和一个杆或棒连接运作，使它上下或往来摆动。

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