| 摘要 |
1,160,521. Wells &c. E. BERGSTROM. 22 Aug., 1966 [25 Aug., 1965], No. 36452/65. Heading E1F. A pipe 13 is thrust through the ground by jacks 17 movable along rails 14, 15 evenly spaced about the periphery of the pipe and located to react against the back 11 of a thrust pit 10. The thrusts of the jacks which are hydraulic are taken by keys 18 engaging slots 19 in the rails. |
