Abstract: In a machining center provided with a mechanized tool magazine and with at least one movable tool-holding spindle capable of accessing the tool magazine, the tool is picked up from the tool-holding spindle and transferred to a tool replacement area by means of a dedicated, automatic transfer device that is independent of the tool magazine. After the replacement of the tool with a new tool in the transfer device, the new tool is returned to the tool-holding spindle by means of the transfer device.

Abstract: A workpiece-holding unit for installation on machining centers for connecting rods, comprising a crosspiece which is adapted to be rotatably supported about its axis in front of a machining head of the machining center and has internal, hydraulic longitudinal ducts which communicate with respective hydraulic outlets on the main faces of the crosspiece and are connected to hydraulic feed means. Several workpiece-holding tools are installable on the main faces of the crosspiece and are provided with positioning mechanisms and locking mechanisms for at least one connecting rod, which are hydraulically operated via respective hydraulic lines leading at positions aligned to said hydraulic outlets.

Abstract: A workpiece-gripping device for tool machines having a motorized chuck mounted on an operating head comprises a housing, a driving shaft journaled in the housing and provided with a shank engageable in the chuck, a locking member configured to engage a reaction member integral with the operating head when the shank engages the chuck, whereby the rotation of the device is prevented when the chuck is driven, and at least a pincer having jaws, of which at least one is movable and operatively connected via transmission means to said driving shaft for opening and closing.

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: The apparatus includes a frame supporting two fixtures, of which at least one is movable, and which have respective crescents adapted to be brought together to form a circular profile engageable with the big end of a connecting rod and separable by an opening device for fracturing the big end of the connecting rod. The opening device comprises a pusher device which has a sloping surface and is slidably supported with respect to one of the crescents to abut against the other crescent, and a driving member, which is slidable transversely to the pusher device under control of driving elements, and has a sloping surface that is adapted to cooperate with a camming action with the sloping surface of the pusher device.

Abstract: A frame (10) carries two fixtures (16, 20), of which at least one (20) is movable, and which have respective crescents (18, 22) adapted to be brought together to form a circular profile engageable with the big end of a connecting rod and separable by opening means for fracturing the big end of the connecting rod.

Abstract: A machining head (36) is drivable along a vertical axis and two horizontal axes with respect to a workpiece held on a workpiece-holding device, and has, at progressively lower levels along said vertical axis, one or two high-speed spindles (44), one or two low-speed spindles (46) and one or two feed-out spindles (48), all arranged at right angles to said vertical axis and driven by one or more motors (42) mounted on the head. The machining head can bring the high-speed spindles to cooperate with a tool-changing magazine (52). The workpiece-holding device (54; 154) is adapted to carry two sets of workpieces on respective supports (56, 58; 170), and to shift said supports in succession between a working position near the head and a tool-changing position remote from the head.

Abstract: A working head for numeric-control machine tools is adapted to be moved along two or three axes relative to one or two parts mounted on respective worktables which can rotate about respective parallel axes. According to the present invention, the head supports one or preferably two tool-supporting spindles which are pivoted about a common axis which is transverse to the axes of the spindles under the actuation of motor means which are rigidly coupled to the head and are controlled by a numeric control unit.

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.

Abstract: The machine includes a first central support, which is rotatably supported by the frame of the spindlehead, and a second planetary support, which eccentrically supports the spindle and is rotatably and eccentrically supported by the central support; the first and second supports are suitable for producing, by virtue of the combination of their mutual rotary motions, movements of the spindle in two mutually perpendicular directions; the spindlehead is in turn supported by a slider with the possibility of moving along a third direction which is perpendicular to the first two.