Rotary drilling rig and hoister thereof

  title={Rotary drilling rig and hoister thereof},
  author={杨绍辉 and 郭聪聪},
The invention discloses a hoister, which comprises an upper connector (21), a middle connector (22) and a lower connector (23), wherein the middle connector (22) is fixedly connected to the lower connector (23) and is rotatably connected to the upper connector (21); the upper connector (21) is provided with a first channel (211); the middle connector (22) is provided with a second channel (221); the lower connector (23) is provided with a third channel (231); the extending directions of the… CONTINUE READING

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