Machine tool

Claim 1

A BORING MACHINE COMPRISING A ROTATABLE BORING SHAFT INCLUDING A BORING HEAD MOUNTING A BORING BAR ADAPTED TO BE ADJUSTED FOR DIFFERENT BORING RADII, THE BORING HEAD HAVING A ROTATABLE LEAD SCREW MOUNTING A TRAVELING NUT FOR RADIALLY POSITIONING THE BORING BAR AND MEANS FOR LIMITING THE TOTAL TRAVEL OF THE NUT, MEANS FOR ROTATING SAID BORING SHAFT, A CONTRAL SHAFT COAXIALLY MOUNTED WITHIN SAID BORING SHAFT TO BE ROTATABLE THEREWITH AND HAVING A DRIVING CONNECTION WITH SAID LEAD SCREW FOR CONTROLLING THE POSITION OF SAID BORING BAR UPON ACTUATION THEREOF, SAID CONTROL SHAFT MOUNTING AN INCREMENTAL POSITION TRANSDUCER ADJACENT SAID LEAD SCREW FOR ROTATION THEREWITH TO SENSE THE INCREMENTAL CHANGES IN THE POSITION OF THE CONTROL SHAFT AND PROVIDING AN ELECTRICAL OUTPUT INDICATION FOR EACH PRESELECTED INCREMENTAL CHANGE IN POSITION, A CONTROL MOTOR MOUNTED IN SAID BORING SHAFT FOR DRIVING SAID CONTROL SHAFT UPON ENERGIZATION THEREOF, COUPLING MEANS INCLUDING SPEED REDUCING MEANS MOUNTED IN SAID SHAFT AND CONNECTED BETWEEN SAID MOTOR AND SAID CONTROL SHAFT FOR DRIVING THE LATTER, TACHOMETER MEANS MOUNTED ON SAID CONTROL SHAFT TO BE DIRECTLY DRIVEN BY SAID CONTROL MOTOR, A FOUR AXIS DIGITAL CONTROL CIRCUIT MEANS INCLUDING ELECTRICAL CONNECTIONS TO SAID TRANSDUCER, SAID CONTROL MOTOR, AND SAID TACHOMETER FOR COMMANDING THE ENERGIZATION AND DE-ENERGIZATION OF SAID CONTROL MOTOR WHILE THE BORING SHAFT IS ROTATING AND THE BORING BAR AND THE WORKPIECE HAVE BEEN POSITIONED INTO CUTTING POSITION, DYNAMIC COUPLING MEANS HAVING ROTARY PORTIONS MOUNTED FOR ROTATION WITH SAID BORING SHAFT AND ELECTRICALLY AND INDIVIDUALLY CONNECTED TO SAID TRANSDUCER, CONTROL MOTOR, AND TACHOMETER AND HAVING A STATIONARY PORTION INDIVIDUALLY COUPLED TO THE ROTARY PORTIONS AND SEPARATELY CONNECTED WITH SAID CONTROL CIRCUIT, SAID CONTROL CIRCUIT MEANS INCLUDING A REGISTER FOR STORING SIGNALS INDICATIVE OF THE DESIRED BORING RADIUS FROM THE LIMITING MEANS, AND A SOURCE OF NUMERICAL COMMANDS CONNECTABLE TO SAID CONTROL CIRCUIT MEANS FOR CONTROLLING THE RELATIVE POSITION OF THE BORING HEAD AND THE WORKPIECE IN ACCORDANCE WITH THE CONVENTIONAL THREE AXES AND FOR PLACING THE NUMERICAL SIGNAL REPRESENTATIVE OF THE DESIRED BORING RADIUS IN THE REGISTER, THE CONTROL CIRCUIT INCLUDING MEANS FOR CONTROLLING THE EXCITATION OF THE CONTROL MOTOR IN ACCORDANCE WITH THE NUMERICAL SIGNALS IN SAID REGISTER.