Patent ID: 7322425
Filing Date: 2008-01-29
Classification: B25D,E21B

Abstract:
1. A method of generating a stress pulse in a tool by means of a pressure fluid operated impact device, a rock drill or a braker, comprising: arranging the tool to be in contact with the material to be struck in order to produce an impact in the material to be processed; feeding pressure fluid to the impact device and discharging the pressure fluid therefrom in order to use the impact device; feeding pressure fluid as pressure pulses to a working chamber residing in the impact device between a frame of the impact device and the tool such that the pressure of the pressure fluid produces a force between the frame of the impact device and the tool, the force pressing the tool towards the material to be processed such that due to the influence of the force; and generating a stress pulse in the tool in its longitudinal direction such that the stress pulse propagates through the tool to the material to be processed, the generation of the stress pulse ending substantially at the same time as the influence of the force on the tool ends.