| 20090101378 | Water Powered Impulsive Unit - An impulsive unit for a jack hammer or rock drill is adapted to be powered by water, and comprises a piston slidable within a cylinder, and carrying a striker portion thereon. At least a portion of the piston and/or cylinder is coated with ceramic. The ceramic is most suitably an aluminum oxide-titanium dioxide composite, which enables the clearance between the internal diameter of the cylinder and the external diameter of the piston to be reduced to between 8 and 10 micro-meters. | 04-23-2009 |
