High-speed handpiece

Claim 1

AN ASSEMBLY FOR DRIVING A CUTTING TOOL COMPRISING, A HOUSING HAVING AN INTERNAL SURFACE DEFINING A CAVITY, SAID HOUSING SURFACE INCLUDING A CYLINDRICAL PORTION, SAID HOUSING INCLUDING FIRST AND SECOND SPACED END WALLS DEFINING THE ENDS OF THE CAVITY, SAID FIRST END WALL INCLUDING A THROUGH BORE IN AXIAL ALIGNMENT AND COMMUNICATING WITH THE CAVITY, A TOOL DRIVE SPINDLE ADAPTED FOR A TOOL, SAID SPINDLE HAVING A SPINDLE SECTION SUBSTANTIALLY FILLING SAID CAVITY AND A SHANK SECTION PROJECTING THROUGH SAID BORE, SAID SPINDLE SECTION HAVING A PERIPHERAL SURFACE INCLUDING A CYLINDRICALLY CONTOURED PORTION, SAID HOUSING AND SAID SPINDLE CYLINDRICAL SURFACE PORTIONS BEING COMPLEMENTAL AND SPACED APART TO DEFINE A RADIAL LOAD CARRYING GAS BEARING THEREBETWEEN, SAID SPINDLE HAVING AN END WALL AT THE END OPPOSITE SAID SHANK SECTION, SAID SPINDLE END WALL AND SAID HOUSING SECOND END WALL BEING COMPLEMENTAL COACTING THRUST SURFACES DEFINING A GAS THRUST BEARING THEREBETWEEN, AND SAID SPINDLE AND HOUSING INCLUDING COACTING MEANS TO CAUSE ROTATION OF THE SPINDLE IN THE HOUSING BY GAS UNDER PRESSURE, A PORTION OF SAID SHANK SECTION AND SAID FIRST END WALL DEFINING A SPACE FOR DIRECTED ESCAPE OF THE GAS UNDER PRESSURE THERETHROUGH TO CLEAR THE AREA ON WHICH THE TOOL IS OPERATING.