| 摘要 |
<p>Threaded coupling for metal tubes comprising a sleeve (10) with two female threaded sockets (8,9) into which the threaded male elements (2,3) of two metal tubes are screwed. These male elements each have an unthreaded end zone terminating at an end wall (11,12). The two end walls press on each other in the screwed position, forming a metal-to-metal contact. The peripheral unthreaded area next to the end wall has a convex conical surface (14,15) which makes contact with a concave conical surface (19,20) in the sleeve, with positive interference to create a watertight metal-to-metal contact. Shoulder stops allow the male elements to be positioned precisely within a well defined zone of tolerance relative to the centre of the sleeve. Method of forming the coupling is also claimed by screwing a first male element into the female until the coupling engages and its advance is blocked by the two shoulder stops making contact, then screwing in the second male element until the two end walls meet.</p> |
