Ram-type test boring system - with leading point comprising concentric disc with diameters decreasing towards end

摘要

In a ram-type of test boring system the leading point consists of several concentric discs with diameters which decrease in steps towards the end. The periphery of each disc is designed as an annular cutting edge with a top rake and a clearance angle. Inclined grooves are arranged on each clearance face and the disc assembly can swivel relative to the drill rods. This eliminates the risk of conventional conical points of being deflected by rock and stressing the drill string to breaking point. The new leading point will not become wedged either.