PERCUSSION PISTON

摘要

(57) Percussion piston (1) for a rock drill machine (2) that comprises a pilot cylinder (3), a distributor (4) and pressure medium comprises a control edge (5) configurable to cause a change in the position of the distributor (4) in a direction parallel to the axial direction of the percussion piston (1) as the percussion piston moves in the impact direction (A) in relation to the pilot cylinder. The control edge (5) of the percussion piston comprises at least one notch (6) provided on the outer peripheral (7) of the control edge and arrangeable to cause a start of a state change for the distributor (4) before the control edge of the percussion piston passes by a corresponding control edge (8) provided on the distributor or the pilot cylinder (Figure 2)