| 摘要 |
The rock-drill has a drill head (2) next to a single or multiple start spiral conveyor (3) which has spiral main webs (6,7),and spiral subsidiary webs (8,9) of smaller diameter. Both webs have conveyor edges (12-15) in discharge grooves (16-19) for transporting bore dust. The drill head consists of a single piece of hard metal (21) welded or soldered to the conveyor spiral so that the main webs are joined to the main cutter-blades (24,25), and the subsidiary webs are joined to the subsidiary cutter-blades (26,27). |
