Boring head

Claim 1

A BORING HEAD COMPRISING A BODY HAVING AT LEAST TWO ELEMENTS SECURED THERETO, AT LEAST ONE OF SAID ELEMENTS BEING A CUTTER, EACH OF SAID ELEMENTS HAVING AT LEAST ONE BEARING SURFACE FOR GUIDING THE BORING HEAD ALONG THE WALL OF A BORE IN A WORKPIECE AND ADAPTED TO TAKE UP THE CUTTING FORCES, SAID ELEMENTS PROJECTING FROM THE PERIPHERAL WALL OF SAID BODY OF SAID BORING HEAD TOWARD THE INNER WALL OF SAID BORE BY MEANS OF ENGAGING BEARING SURFACES, SO AS TO FORM A SUBSTANTIALLY ANNULAR GAP BETWEEN SAID BODY AND THE WALL OF SAID BORE AND EXTENDING PERIPHERALLY BETWEEN SAID ELEMENTS, SAID BODY DEFINING AN AXIAL CHANNEL THEREIN, SAID ANNULAR GAP AND SAID CHANNEL BEING ADAPTED TO FEED A COOLANT TO SAID BORING HEAD, EACH OF SAID BEARING SURFACES DEFINING A LINE EXTENDING IN AXIAL DIRECTION OF SAID BODY AND DIVIDING SAID SURFACE INTO A CONTACT SURFACE EXTENDING SUBSTANTIALLY COAXIALLY TO AND ENGAGING THE WALL OF SAID BORE AND INTO A LEAD SURFACE, AND THE LATTER TOGETHER WITH THE WALL OF SAID BORE DEFINING A FEED GAP OF A WEDGE-SHAPED CROSS SECTION ADAPTED TO SUPPLY SAID CONTACT SURFACE WITH SAID COOLANT UNDER THE PRESSURE PRODUCED BY THE RELATIVE ROTATION BETWEEN SAID BORING HEAD AND SAID WORKPIECE, SAID CONTACT SURFACE AND SAID LEAD SURFACE FORMING A CONTINUOUS CURVED FACE, AND SAID LEAD SURFACE PROVIDING A FEEDING OPENING FOR SAID COOLANT AND BEING REMOTE FROM THE LEADING EDGE OF SAID BEARING SURFACE SUCH THAT HYDRO-DYNAMIC PRESSURE CREATED DURING RELATIVE ROTATION BETWEEN SAID BORING HEAD AND THE WALL OF SAID BORE IS SUFFICIENT TO ASSUME THE RADIAL COMPONENT OF THE CUTTING FORCES OF THE BORING HEAD EXERTED AGAINST THE CONTACT SURFACES.