Borehole expanding impact tool with conical nose - has additional conical nose shells placed on impact tool nose

摘要

The arrangement for making and expanding of boreholes in the ground has a cylindrical housing with on pointed end. The housing accommodates a pressurised medium loaded flating impact piston and the borehole enlarging conical nose shell is fitted on the working end of the device. Boreholes are expanded without excessive forces being exerted on the housing. The conical nose shell (5) is fitted on the conical nose (4) of the cylindrical device. The nose shell has a cylindrical rim (6) on its larger end and the conical nose of the device has a cylindrical pin on its narrow end. Borehole diameters can be enlarged by successive application of increasing sizes of conical nose shells.