Drive shield
US4112696A · kind A · utility
2Cited by
3References
15Claims
0Family size
Inventors
Key dates
| Filing date | Apr 25, 1977 |
| Grant date | Sep 12, 1978 |
| Priority date | — |
| Expiry date | Apr 25, 1997 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21D9/0692
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A drive shield for use in tunnelling operations includes a generally cylindrical cutting edge supported by a frame. A knife shield is telescoped together with the cutting edge, the knife shield having a plurality of elongate members (or planks). Each of the planks is extensible relative to the cutting edge in the direction of tunnel advance. In use, all the planks are advanced relative to the cutting edge which is then advanced in a follow-up sequence.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.