| 摘要 |
When parallel shotholes have to be drilled during driving of tunnels and headings in mines, a lack of parallelism caused by the conventional mechanical and hydraulic booms results in high explosive consumption. This can be avoided and the drill rig itself need not be previously aligned if a guide rod (3) is inserted into a pilot borehole (1) in the tunnel face (2), and a laser (4) is fixed to its end. Telescopic arms (6, 7) on the rock drill slide (5), joined by a cross-piece (8), carry orifice plates (9, 10) at the end. When they are adjusted so that the laser passes through both orifices, the slide (5) is aligned parallel to the pilot hole. |
