| 摘要 |
<p>The ring is for locking the balls or discs of dumb-bells on to their bar. It consists of a cylindrical boss (1), made of natural or synthetic rubber, whose interior diameter corresponds to the diameter of the bar. Inside the boss there is a thick metal collar (4) that is concentric with the boss. There is a radial thread in the collar (5) corresponding to a hole in the outer part of the boss. A screw is screwed into this to compress the inner part of the boss and hold it on to the bar.</p> |
