这种抽油机以连杆式换向机构取代原有的十字滑块式换向架，以重块平衡代替气平衡，并改进了导向系统。

The new unit uses the pitman reserse mechanism instead of the crosshead slide reverse rack, adopts weight balancing instead of air balancing, and is provided with an improved guiding system.

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无换向架链条抽油机的链条承受的总拉力为悬点载荷与平衡重的差值加连杆对链条的水平分力在链条上形成的附加拉力之和，受力状况优于普通链条抽油机，且能得到控制。

The force conditions of the chain on a chain drive pumping unit without reverse rack are much more favorable than that on conventional chain drive pumping units, and can be well controlled.

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