| 摘要 |
The invention relates to a pressurised fluid flow system for a down-the-hole hammer drill, including a plurality of working chambers, i.e. one or more auxiliary lifting and driving chambers, as well as two main chambers located at opposite ends of the piston, each of the auxiliary chambers being formed around respective belts on the piston and being defined externally by respective sleeves disposed longitudinally in series. Two or more internal chambers filled with pressurised fluid are defined by recesses in the internal surfaces of the piston in order to supply the fluid to the working chambers, which is controlled co-operatively by the piston and by a coaxial control tube disposed inside the central opening in the piston. One ore more discharge chambers are formed between the external casing and the sleeves in order to empty the working chambers through the discharge openings in the sleeves. The invention also relates to normal- and reverse-circulation down-the-hole hammer drills comprising said system. |
