| 摘要 |
<p>In the shell is an annular throat entered by a drive element of the socket. The element is divided into sections and fits the throat. The throat has a rounded cross section. The drive element enters an annular groove of the socket. Pref. the element is circumferentially divided into two parts, corresp to the socket, or three parts. It may be a set of balls, or a toroidal ring in several pieces.</p> |
