Abstract: According to one aspect of the invention hydraulic pressure pulses are created in a rock drill machine utilizing a rod (7, 7a, 7b) made of a magnetostrictive material arranged in one or more actuators (5, 5a, 5b), which exposes an impulse piston (3) in a pulse cylinder (1) to said hydraulic pressure pulses, whereby mechanical pressure pulses being transferred to a drill steel of the rock drill machine are generated in the impulse piston (3).

Abstract: A gas driven oscillator (10) comprising an engine (11) having a cylinder (12) and a pair of expansion chambers (13, 14) on either side of a floating piston (15) adapted to reciprocate within the cylinder (12). The piston (15) is mounted on a piston rod (16) extending through the cylinder (12) and into a compressor (17). Compressed air is delivered from a tank (20) to the engine (11) via a pair of valves (22, 23) mounted on an adjustment screw and slidably disposed on the piston rod (16). The spacing between the valves (22, 23) can be adjusted in order to vary the amplitude of the piston (15) within the cylinder (12). The piston rod (16) includes spaced slots (24, 25) which alternate align with passages inside the respective valves (22, 23) to deliver a pulse of compressed air to the respective chambers (13, 14) of the cylinder (12). Mercury is added to or discharged from a tank (42) which is rigidly secured to piston rod (16) to vary the inertia of the oscillator (10).

Abstract: A gas driven oscillator (10) comprising an engine (11) having a cylinder (12) and a pair of expansion chambers (13, 14) on either side of a floating piston (15) adapted to reciprocate within the cylinder (12). The piston (15) is mounted on a piston rod (16) extending through the cylinder (12) and into a compressor (17). Compressed air is delivered from a tank (20) to the engine (11) via a pair of valves (22, 23) mounted on an adjustment screw and slidably disposed on the piston rod (16). The spacing between the valves (22, 23) can be adjusted in order to vary the amplitude of the piston (15) within the cylinder (12). The piston rod (16) includes spaced slots (24, 25) which alternate align with passages inside the respective valves (22, 23) to deliver a pulse of compressed air to the respective chambers (13, 14) of the cylinder (12). Mercury is added to or discharged from a tank (42) which is rigidly secured to piston rod (16) to vary the inertia of the oscillator (10).