| 摘要 |
The pit has a hollow body, a lid mounting frame above it located flush with the aircraft servicing surface and defining a pit access opening into the hollow body. It has a number of biasing springs interposed between the hollow pit body and the pit lid where all of the biasing device are arranged so as to initially urge the pit lid from the horizontal seated position toward the fully raised position. There is a member for disengaging at least one of the biasing springs when the lid reaches an intermediate position as a result of a manual lifting force applied to it in moving from the horizontal seated position toward the fully raised position and reengaging the at least one of the biasing device when the lid reaches the intermediate position in moving from the fully raised position toward the horizontal seated position. |
