In 1817, another British Roberts adopted with round 4 wheel mechanism and back to change spindle speed.

1817年，另一位英国人罗伯茨采用了四级带轮和背轮机构来改变主轴转速。

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In 1817, another British Roberts adopted with round 4 wheel mechanism and back to change spindle speed.

1817年，另一位英国人罗伯茨采用了四级带轮和背轮机构来改变主轴转速。

youdao