Abstract: The plasma cutting device of the present invention comprises a plurality of release ports for releasing the work gas to prevent adverse influence on the cutting processing besides the exhaust port for jetting the gas toward the work. Accordingly the flow rate and velocity of the swirl flow are increased and the flow rate of the jet gas is still kept the same as that in the conventional device, resulting in stabilizing the plasma arc and performing superior cutting.

Abstract: A plasma arc workpiece cutting device having means for removing a deposited material deposited onto a nozzle of a plasma torch. During plasma arc cutting operation, molten spatters may be directed toward the plasma torch and may be adhered onto the nozzle. The deposited material is removed by way for removing the deposited material. At every proper intervals, the plasma torch is moved toward the removing structure, and the deposited material is brought into sliding contact therewith in order to frictionally remove the deposited material from the nozzle. A control system is provided for moving the plasma torch at every proper timings so as to perform the deposited material removing operation.

Abstract: A plasma-arc cutting apparatus having a plasma torch producing a plasma arc and cutting a workpiece with the plasma arc, the plasma torch including a nozzle from whcih the plasma arc is ejected toward the workpiece; a feed device moving the plasma torch relative to the workpiece; a magnetic-field forming device producing a magnetic filed, and applying the magnetic field to the plasma arc so as to intersect the plasma arc and thereby deflect the arc; a first control device numerically controlling the feed device according to cutting operation information, the cutting operation information including cutting path data representative of a predetermined curved cutting path along which the plasma torch is moved over the workpiece, the first control means providing torch position data representative of a current position of the plasma torch relative to the workpiece; and a second control device controlling the magnetic-field forming device according to the cutting operation information and the torch position data so

Abstract: In a plasma cutting apparatus for cutting a workpiece with a plasma arc, a cutting torch moves relative to the workpiece. The cutting torch produces plasma arc in accordance with a cutting current supplied thereto. To improve surface roughness of the cut facet of the workpiece, a pulsating current is superimposed on a D.C. current to provide the cutting current, wherein the frequency of the pulsating current is controlled in accordance with the moving speed of the cutting torch.

Abstract: A machine tool with a vertically reciprocating spindle head has an automatic tool changer including a rotatingly indexable tool support connected to the machine tool frame and vertically movable independently of the spindle head, a first cam-and-crank mechanism activated by spindle head vertical movement to move the tool support with the spindle head during a first portion of the tool changing operation and away from the spindle head during a second portion of the tool changing operation, a second cam-and-crank mechanism also activated by spindle head vertical movement for opening and closing a tool holder on the tool support during another portion of the tool changing operation, a tool holder with a pair of rotatably supported L-shaped fingers which hold a tool in a substantially perpendicular direction to the axes of finger rotation, a tool taking device for taking a tool out of a tool magazine, and a vertical stop for preventing vertical movement of the tool support with the spindle head into the machining