overhead door holder

例句：

1. 1.The overhead door holder is a crucial part of the elevator's operation.
   门上方固定装置是电梯运行的关键部分。
2. 2. The overhead door holder was designed to prevent the elevator from colliding with the ceiling.
   门上方固定装置被设计来防止电梯与天花板相撞。
3. 3. The overhead door holder was removed for maintenance, causing the elevator to stop working.
   为了维护，移除了门上方固定装置，导致电梯停止工作。