| 摘要 |
<p>678,613. Pipe joints. DEHN, S. G. (Hughes Tool Co.). Sept 22, 1948, No. 24830/48. Class 99 (i) A joint for tubular oil well drill stems comprises tapered engaging screw-threads on spigot and socket, and plain engaging tapered surfaces in line with the screw-threads constituting the only seal, all the coacting threads being of uniform depth. The screw. threads of the spigot project above the plain surface 14, and the root of the socket threads is joined to the plain tapered surface 16 by a cylindrical portion 15. The plain surfaces may extend on one or both sides of the screw-threads. There may be interfitting cylindrical portions on either side of the screwthreads.</p> |
