| 摘要 |
The invention is a hoist system for a derrick with a derrick inside, a derrick outside, and a derrick top side; a splittable block connected to the derrick top side; a hoisting cable guided through the splittable block; a moveable trolley with a trolley top side and a trolley bottom side, wherein the trolley is connected to the splittable block and wherein the moveable trolley is removably secured on the derrick; and a hoist winch adapted to pull the hoisting cable over the derrick top side and through the splittable block to move the moveable trolley relative to the derrick.
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