Pulley is the key to open and close the Ji'nan guardrail is not smooth, the use of rolling bearing nylon wheel.

滑轮是济南护栏启闭是不是顺利的关键所在，应运用滚动轴承尼龙轮。

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LD wheel, wheel group, drum group, hook group, pulleys, couplings, wire rope, cable pulley, motor, brake, reducer, cable reel, overload limiter, standard parts.

LD车轮，车轮组，卷筒组，吊钩组，滑轮组，联轴器，钢丝绳，电缆滑车，运行电机，制动器，减速机，电缆卷筒，超载限制器，标准件。

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Pulley: in mechanics, a wheel that carries a flexible rope, cord, cable, chain, or Belt on its rim.

滑轮：力学上的一种装置，在边缘装有活动绳索、弦、缆、链条或带子的轮。

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We decided to exclude the traditional list of "simple machines, " which includes the lever, pulley, wheel and wedge, since most other tools employ some form of simple machine--a hammer is basically a lever, and an axe is essentially a wedge.

FORBES: Methodology