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AssigneeTamrock Oy
InventorsTimo Muuttonen, Aimo Helin, Timo Kiikka, Jorma Mäki, Pekka Salminen
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A method for adjusting percussion pressure and a drilling machine. In the method the percussion power of a drilling machine is adjusted by moving a shank in the longitudinal direction of the drilling machine forwards when a smaller percussion power is to be transferred from the percussion piston to the shank. The drilling machine comprises at least two groups of pistons moving in the axial direction of the drilling machine, the pistons being connected to act on the shank by means of a pressure medium acting behind the pistons towards the front end of the drilling machine. The drilling machine comprises at least two separate groups of pistons whose travel with respect to one another is different and where pressure medium channels separate from one another lead to the cylinder spaces of both piston groups.
A method for adjusting drilling of a drilling machine, said drilling machine comprising a frame, a percussion piston supported in the frame for movement along a longitudinal axis, an absorber disposed at a front end of travel of a piston portion of the percussion piston so as to be contacted by the piston portion at the front end of travel of the piston portion, a shank supported in the frame in axial extension of the percussion piston so as to be impacted by said percussion piston in a working stroke thereof and at least two control pistons supported in the frame for longitudinal movement, said control pistons being disposed in cylinder spaces arranged around the longitudinal axis for moving the shank longitudinally to a selected percussion point at which the percussion piston impacts against the shank, said method comprising:
A drilling machine comprising a frame, a percussion piston supported in the frame for movement along a longitudinal axis, an absorber disposed at a front end of travel of a piston portion of the percussion piston, so as to be contacted by said percussion piston in a working stroke thereof, a shank supported in the frame in axial extension of the percussion piston so as to be impacted by said percussion piston in a working stroke thereof, and an axial bearing arranged in the frame for receiving axial forces applied to the frame via the shank during a drilling operation, said axial bearing comprising at least two control pistons supported in the frame for longitudinal movement, said control pistons being disposed in cylinder spaces arranged around the longitudinal axis for moving the shank longitudinally to respective selected percussion points at which the percussion piston impacts against the shank, said cylinder spaces of each of said at least two control pistons being connected by respective pressure channels to receive pressure medium from different pressure sources at different pressures to produce respective strokes for said control pistons to move the shank to respective selected percussion points, at least a first of said control pistons having a length of stroke to move the shank to an optimum percussion point at which a maximum impact force is applied to the shank by the percussion piston, and at least a second of said control pistons having a greater length of stroke than that of said first control piston to move the shank away from said optimum percussion point to another percussion point at which the impact force of the percussion piston on the shank will be reduced.
Dependencies are inferred from the claim text.