Abstract: A sensor detects an axial position of a rod controlling a tool-gripping collet in a tool-holding spindle whenever a tool is picked during a working session. The current obtained rod position value is compared with previous rod position value, which has been obtained and stored during the previous tool-picking and, if their deviation is larger than a predetermined threshold, the collet closure is notified as defective. The rod position is obtained as an average of a plurality of closely spaced readings, which are taken after a predetermined delay from the collet closure.

Abstract: A sensor detects an axial position of a rod controlling a tool-gripping collet in a tool-holding spindle whenever a tool is picked during a working session. The current obtained rod position value is compared with previous rod position value, which has been obtained and stored during the previous tool-picking and, if their deviation is larger than a predetermined threshold, the collet closure is notified as defective. The rod position is obtained as an average of a plurality of closely spaced readings, which are taken after a predetermined delay from the collet closure.

Abstract: A numerical control unit issues a sequence of instructions for causing a spindle of a cutter disk in a tool machine to perform successive straight displacements approximating a spiral of Archimedes, with a predetermined angle step from one point to the next, and issues one or more ADIS instructions for merging each of the straight displacements with the next. The spiral path is such that the cutter disk will progressively shave a chip of a predetermined thickness over several revolutions, until its cutting edge is near the intended groove bottom. The tool is then caused to follow a merging path leading to a final point lying on the intended groove bottom, and finally is caused to follow a full circular path coaxial to the bore starting from the final point.

Abstract: A numerical control unit issues a sequence of instructions for causing a spindle of a cutter disk in a tool machine to perform successive straight displacements approximating a spiral of Archimedes, with a predetermined angle step from one point to the next, and issues one or more ADIS instructions for merging each of the straight displacements with the next. The spiral path is such that the cutter disk will progressively shave a chip of a predetermined thickness over several revolutions, until its cutting edge is near the intended groove bottom. The tool is then caused to follow a merging path leading to a final point lying on the intended groove bottom, and finally is caused to follow a full circular path coaxial to the bore starting from the final point.

Abstract: According to the invention, parting of the cap of the connecting rod is achieved by engaging the eye of the big end of the connecting rod with two semicylindrical fixtures, respectively a fixed fixture and a movable fixture, which are actuated by a hydraulic actuator which is interposed between them and is adapted to expand the fixtures in a diametrical direction against the inner surface of the eye of the big end of the connecting rod, subjecting the piston of the actuator to the action of a hydraulic fluid fed into the respective actuation cylinder at an optional pre-loading pressure that is in any case lower than the pressure required to reach the yield point of the material of the connecting rod, and producing an instantaneous peak in the pressure of the fluid fed to the hydraulic actuator by means of an auxiliary piston that is subjected to the momentary action of a striking mass.