| 摘要 |
<p>1,029,308. Tunnels; tunnelling shields. M. F. KEMPER. Nov. 19, 1962, No. 53925/65. Divided out of 1,029,307. Heading E1F. A tunnelling shield has means for supporting the earth at the face of the tunnel, the means comprising earth retaining members 49, 50, 51 and yieldable means 44, 45 carried by the shield and forcing the members into engagement with the earth. The yieldable means comprise pistons and cylinders to which air is supplied.</p> |
