Abstract: A control system for a direct teaching/playback type robot, including a low spring constant member connected to a drive source for driving a robot element through a frictional coupling. The control system basically includes a first incremental position detector provided between the robot element and the frictional coupling for detecting the rotational position of the robot element, a second incremental position detector connected to the drive source for detecting the rotational position of the drive source, and a switch for selectively connecting the output terminals of the first and second position detectors to a drive source controller in teaching and playback modes of operation, respectively.

Abstract: A gravity offsetting device for offsetting the gravitational moment of a rocking arm, mounted between a fixed point located above a pivotal point of the rocking arm at a predetermined distance a and substantially in vertical alignment therewith, and an arbitrary point on the rocking arm, the gravity balancing device including: a compression spring having a spring constant k of a value corresponding to the load W at the arbitrary point as divided by the distance a, and a free length corresponding to the sum of the length l between the fixed and arbitrary points and the initial set length l.sub.s of the compression spring, and adapted to apply a counterbalancing tensile force varying in proportion to the distance between the fixed and arbitrary points.

Abstract: A multi-articulated arm mechanism including a first shaft rotatably mounted on a first base plate; a first arm mounted pivotally only in a plane extending through and parallel with the first shaft; a first positioning mechanism for determining the angle of the first arm with the first shaft; a second arm attached to the first arm and pivotable only in the first plane; a second positioning mechanism for determining the angle of the second arm with the first arm; a slide arm connecting a third fulcrum point on a second base plate located remote from the first plane to a second fixed fulcrum point on the second arm; and a third positioning mechanism for determining the length of the slide arm.

Abstract: Arm having a gravity-balancing function effective for use in welding robots as well as robots employed in a variety of industrial fields. Projectively provided over the fulcrum of an arm (1) is a rotary sheave (2), whose position is perpendicularly maintained regardless of the vertical swaying of the arm (1). A wire (6) is extended from an action point (A) on a line traced by the center of gravity of the arm (1), to the rotary sheave (2), and is connected to a spring mechanism (3) which may extend by the length of elongation equal to the distance between the action point (A) and the rotary sheave (2), whereby a moment due to the weight of the arm (1) is completely balanced to provide an arm with gravity-balancing.

Abstract: Billet milling equipment including first frames which are laid on a traveling path of a billet, a pair of upper and lower clamping frames which are movable so as to follow a deformation of the billet and which are installed on the first frames, and milling cutter units which normally follow a surface of the billet to be cut in correspondence with the deformation of the billet and which are installed on the clamping frames in a manner to be capable of advancing or retreating relative to the surface to-be-cut. On the basis of a signal from a flaw detector, a milling cutter of the milling cutter unit which is following the deformation of the billet is rotated in pressed contact with the surface to-be-cut of the billet, whereby a flaw is removed by the cutting.

Abstract: In a teach-in operation, the working procedure is memorized in an industrial robot in advance of the actual working operation, and the teaching is accomplished by manually guiding the tracing tip of the robot arm along a desired path. The teach-in method comprises the step of attaching, to the end of the arm, the tracing tip having at least a displacement pulse oscillator, which consists of a projector and a phototransistor, and a roller provided with gaps such as holes or slits, the projector and phototransistor being arranged in concentric positions with respect to the respective gaps of the roller so as to form an optical axis between the two optical elements. The tracing tip is then moved along a desired path, so that the location signal of the tracing tip may be obtained by the displacement pulse oscillator, whenever the roller is rotated a certain distance, as a result of the movement of the tracing tip, and such a location signal is memorized in a memory.