METHOD AND ARRANGEMENT OF CONTROLLING OF PERCUSSIVE DRILLINGBASED ON THE STRESS LEVEL DETERMINED FROM THE MEASURED FEED RATE

摘要

The rock drill apparatus (1) comprises a rock drill machine (6) provided wit h a percussion device (4), a feed device (9) and a tool (7), the tool (7) end comprising a bit (8) for breaking rock. The tool (7) is arranged to transmit impact energy generated by the percussion device (4) as a compression stress wave to the bit. The feed device (9) is arranged to thrust the tool (7) and the bit (8) against the rock to be drilled, whereby on drilling at least par t of the compression stress wave generated by the percussion device (4) to the tool (7) reflects from the rock to be drilled back to the tool (7) as tensil e stress, and impact energy of the percussion device (4) is adjusted on the basis of the level of tensile stress (.sigma.v) reflecting from the rock.