首先把v 形皮带挂到缝纫机皮带轮上。

Put the V belt on the pulley of the sewing machine.

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这样形成的凹曲线在运行中有使皮带脱离槽形托辊和机架形成的轨迹，结果造成大问题。

Concave curves in conveyors have the tendency to lift the conveyor belts out of the curves and the troughing idlers, resulting in Big Problems.

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如图中箭头所示：槽形托辊组成中对皮带运行有实质影响的唯一部分就是中心托辊。

The only part of the troughing idler that hs any training effect on the conveyor belt is the center roll indicated by the arrow.

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