ARRANGEMENT IN ROCK DRILL AND METHOD OF CONTROLLING ROCK DRILLING

摘要

An arrangement in a rock drill comprising a shank (3) and a percussion piston (2) and lifting means for moving the shank (3) towards the percussion piston (2), and a method of controlling rock drilling. The arrangement comprises a lifting sleeve (7) around the shank (3) and a plurality of cylindrical lifting pistons (8a, 8b) around the shank (3). In the method, upon downward drilling, the magnitude of the feed force of the rock drill is decreased as the number of extension rods increases, and a force is set to act on some lifting pistons to move the shank (3) towards the percussion point.