这把雨伞的顶端有一个金属箍，防止伞骨开裂。

The umbrella has a metal ___ferrule at the top to prevent the ribs from splitting.

这些画笔的金属箍正在生锈，但刷毛仍然牢固。

The ___ferrules on these paintbrushes are rusting, but the bristles remain secure.

这把锤子的金属箍松动了，需要重新固定。

The ___ferrules on this hammer are loose and need to be tightened.