| 摘要 |
The columns (15) are sustained and guided by tractors or other suitable means and terminally carrying the excavation tools (21), such improvements including in combination and coordination a support and positioning auxiliary platform (16) which is at least partially mobile, a support plate (27) which is at least partially rotating and sustained by said auxiliary platform (16) and supporting the said telescopic column; there being included means (18) for generating the frontal oscillation of the auxiliary platform (16) and means (32) for generating the partial rotation of the said support plate (27). |
