| 摘要 |
<p>1,042,941. Tunnelling machines. ECONOMIC FOUNDATIONS Ltd., N. D. PIRRIE and J. BLAND. June 25, 1963 [Feb. 13, 1963], No. 5907/63. Heading E1F. In a tunnelling machine the cutter head is positioned within to extend beyond a shield and is effective in cutting in either direction of rotation of the: head. The hydraulic system for causing rotation of the head and advance of the head and shield forms the subject of the referred to Specification 1,042,942.</p> |
