| 摘要 |
1,107,807. Ladder type trench excavators. R. B. PECK. 29 June, 1966 [16 July, 1965], No. 29190/66. Heading E1F. In a trenching machine having a boom structure about which one or more scraper chains are caused to circulate there is provided within the loop or loops of the chain or chains a backboard to prevent back fall into the excavated trench of material scraped from the leading face of the trench by chain supported cutter teeth formed solely by side and front cutting surfaces. |
