Coupling & Uncoupling第 15 / 60 题
Why is it important that the kingpin be properly locked, not just resting on the closed fifth wheel jaws?
a.To reduce fuel use
b.To keep the fifth wheel greased
c.Because a kingpin resting on top of the closed jaws (a false coupling) can slip out and separate the trailer
d.Because it makes turning easier
解析
A false coupling occurs when the fifth wheel jaws close but the kingpin is sitting on top of them rather than locked around the shank. This looks connected but can separate under load or over bumps, dropping the trailer. That is why the tug test and the visual under-trailer check are both required.
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