Arrangement with striker machine - comprises drill crown with length less than 80 per cent of that of striker piston

摘要

The striker piston moves forwards and backwards in a machine to strike against a drilling tool, and in the housing front part is a drill casing rotatable by a motor with a gearwheel engaging in cogs on the casing. The drill casing has its front end threaded to connect it to a tube constituting its extension. A set of tubes are connected to each other by threaded unions, and to their front end a drill crown is coupled by a splined union. A bar is arranged in the drill casing to transmit striker energy to a set of bars axially movable in the set of tubes, and thence to the drill crown. The drill crown has a work part and a shaft. In the crown is a wash channel which only extends axially in the shaft. The bar next to the crown has an axial flow channel connecting to that in the crown.