Patent ID: 7404458

Claim:
A rotary percussive drilling device, adapted for use in low-height mine galleries, having a drill body of generally cylindrical shape, connected by a pipe to a remotely located high-pressure water pump, a striking piston being mounted to be movable by translation in the drill body and being subjected to a pulsed high water pressure so as to be moved with a percussive movement against a bit-carrying anvil, the pipe simultaneously transmitting a rotary movement to the drill body about its principal axis, wherein the drill body is connected by a flexible pipe to a water pump placed on a low-height carrying vehicle, and a solenoid valve is interposed on the carrying vehicle between the water pump and the point of departure of the flexible pipe, the solenoid valve receiving, in operation, successive electrical pulses to cause its opening and closing, which create shock waves in the water column contained in the flexible pipe, and which transmits these shock waves to the striking piston, which is resiliently returned, of the drill body.