Threaded sleeve has internal and external thread and is made by winding strip with T-shaped cross-section into spiral, cross-bar of T forming threads, while base of upright fits into slot in cross-bar below to hold sleeve together

摘要

The threaded sleeve has both an internal and an external thread. It is made by winding a strip (2) with a T-shaped cross-section into a spiral. The cross-bar (3) of the T forms the internal and external threads, while the base of the upright (4) fits into a slot (6) in the cross-bar of the winding below, holding the sleeve together.