Abstract: An industrial robot having a hollow arm rotatable in a plane perpendicular to the longitudinal axis of a spindle of a machine tool, a wrist mechanism attached for rotation at one end of the arm, the wrist mechanism having a rotary shaft, and a gripper connected to the rotary shaft of the wrist mechanism for being rotated thereby. There are provided first and second air cylinders colinearly disposed within the arm, the first cylinder being fixed and the second cylinder being movable longitudinally of the arm. A piston rod interconnects the first and second air cylinders, the piston rod having a first piston at one end received in the first cylinder and a second piston at the other end received in the second cylinder. The piston rod is moved longitudinally of the arm by introducing air selectively into the first and second air cylinders. A pulley is affixed to the first cylinder, and a tension member such as a wire or belt is connected between the rotary shaft of the wrist mechanism and the pulley.

Abstract: A three-dimensional tracer control system which is provided with an integration circuit for integrating the difference between a Z-axis direction displacement signal and a reference displacement signal and an adder for adding together the above-mentioned difference and the output from the integration circuit. The trace velocity in the Z-axis direction is controlled by the output from the adder, by which it is possible to perform tracing, with the Z-axis direction displacement signal and the reference displacement signal held nearly equal to each other; consequently, machining accuracy is increased.

Abstract: A method and apparatus for numerically controlling a machine tool having at least two tools which are arranged to move in unison with a constant position relationship with respect to one another, the tools being moved relative to a workpiece in accordance with absolute commands to machine a workpiece in a prescribed manner. A single current position register, comprising a section for storing X coordinates and a section for storing Z coordinates, is provided to store the current position of a first tool. Further provided are arithmetic means, responsive to a command for setting coordinates, for computing the current position of a second tool, as well as pulse distribution means.

Abstract: A gripping device on an industrial robot is provided with a plurality of light-emitting members for generating a plurality of light beams that intersect at predetermined angles, and with a plurality of light-receiving elements for receiving the light beams. When the gripping device moves relative to an object that is to be gripped, the object intercepts the light beams, on the basis of which the position of the object relative to the gripping device is detected. This permits even an object which is not precisely located at a predetermined position to be gripped accurately by the gripping device following detection of the object position.

Abstract: A wire-cut, electric discharge machine in which a pair of rollers are provided in the vicinity of each of the upper and lower guides of a wire running system for gripping therebetween a wire with constant pressure. When the wire breaks, the pairs of rollers hold the wire to prevent it from coming off the running system.

Abstract: A programmable sequence controller which need not be equipped with a tape reader for reading a paper tape bearing a punched sequence program or the like. A prepared sequence program or the like is punched in a paper tape in accordance with the standards of a paper tape reader which is provided in a numerical control device, and then is transferred from the numerical control device to a random access memory in the programmable sequence controller. The sequence program is read from the random access memory to permit the execution of sequential operations by processing the program.

Abstract: During a tracing operation of a tracer head for detecting the surface configuration of a model, the current position of the tracer head in the Z-axis direction is detected and a maximum value of the detected tracer head positions is stored in a memory means. When the tracer head is returned from a trace terminating end to a trace starting end, it is quickly returned to a position corresponding to the sum of the stored maximum value and a constant value.

Abstract: In a closed loop type numerical-controlled machine tool in which position control of a mechanical moving part is performed in accordance with a position error variable obtained by making a comparison between commanded positional information and detected positional information from a position detector mounted on the mechanical moving part, deteriorated performance resulting from the inclusion of the mechanical moving part in the closed loop is improved by using correcting means incorporated in the numerical-controlled machine tool.

Abstract: A tool breakdown detecting system having at least one predicted standard pattern of change in the cutting resistance of a tool corresponding to a possible breakdown is prestored in a memory and compared with an actual change pattern of the cutting resistance of the tool monitored during working. When a coincidence is found between the prestored change pattern and the actual change pattern of the tool this indicates a breakdown of tool an alarm signal is generated. The alarm signal can activate a visual or audible alarm as well as regulate the further movement of the tool.

Abstract: A bus connection system in which data transmission and reception between a central processing unit and a memory, an input/output control circuit or like peripheral circuit is performed via a bus. A plurality of buses are each connected to the central processing unit via a driver and a receiver, and the driver and the receiver are controlled by the central processing unit.