flush head screw shackle

例句：

1. 1. The engineer needed to flush the head screws on the new machine before it was putinto use.
   工程师在机器投入使用前需要冲头螺丝。
2. 2. The car's suspension system is designed to shackle the wheels together for better handling.
   汽车的悬挂系统设计用来将车轮连接起来，以改善操控性能。
3. 3. The thief used a shackle to lock the door and escape through a window.
   小偷使用锁链将门锁住，然后从窗户逃跑。