Apparatus for performing a drilling operation on a workpiece

Claim 1

APPARATUS FOR PERFORMING A DRILLING OPERATION ON A WORKPIECE, COMPRISING A SPINDLE, A NON-ROTARY SLEEVE COAXIAL WITH SAID SPINDLE, SAID SLEEVE CUP-LIKE IN FORM WITH A COAXIAL APERTURE IN ITS BOTTOM WALL, SAID CUP-LIKE SLEEVE HAVING AN ANNULAR LIP TO ENGAGE OVER A HOLLOW NONROTARY CYLINDRICAL PORTION OF A DRILLING MACHINE SURROUNDING SAID SPINDLE, MEANS HOLDING SAID ANNULAR LIP ENGAGED WITH SAID CYLINDRICAL PORTION, SAID HOLDING MEANS COMPRISING AN AXIAL SLIT EXTENDING THROUGH THE ANNULAR LIP AND CLAMPING SCREW MEANS EXTENDING ACROSS THE SLIT, SAID SPINDLE ADAPTED TO BE DRIVEN, A DRILL BIT, SAID DRILL BIT HAVING A CYLINDRICAL PORTION INTERMEDIATE ITS ENDS, SAID CYLINDRICAL PORTION HAVING A LONGITUDINAL DUCT WHICH COMMUNICATES AT ONE END WITH A LATERALLY-DIRECTED INLET PORT AND AT THE OTHER END WITH A LATERALLY-DIRECTED DELIVERY PORT IN THE OPERATIVE PORTION OF THE DRILL BIT, SAID SPINDLE AND THE END OF SAID DRILL BIT ADJACENT ITS LATERALLY-DIRECTED INLET PORT ADAPTED TO BE DRIVINGLY INTERCONNECTED COAXIALLY WITH EACH OTHER WITH SAID DRILL BIT EXTENDING THROUGH THE COAXIAL APERTURE, SAID SLEEVE HAVING A BORE OF GREATER DIAMETER THAN THE CYLINDRICAL PORTION OF SAID DRILL BIT WHEREBY AN ANNULAR SPACE IS FORMED BETWEEN THEM, FACING ANNULAR SEALING MEMBERS AXIALLY SPACED IN THE ANNULAR SPACE WHEREBY THE BORE THE CYLINDRICAL PORTION OF