Abstract: The present invention is an industrial robot which has a feed screw that can be easily position in relation to the direct-acting guide. It has a power transmission device that can be removed from the supporting frame which the feed screw is left attached to the supporting frame, so that positioning of the feed screw is very easy. As a result if the simplicity in design machining is only required for the attaching surface for the direct-acting guide, the middle plate, the top plate, and the bottom plate, the cost of production is reduced.

Abstract: An arm drive device for an industrial robot comprises a first arm rotatably supported on a supporting body, a second arm rotatably supported at the first arm and, a ball screw having a base portion adapted for rotatably supporting the end portion of a screw element which is rotatably supported at the supporting body. A nut portion is rotatably connected to a member for driving the first arm or the second arm, and a drive motor is provided for rotationally driving the ball screw. The drive motor is disposed at a position shifted but parallel to the center axis of ball screw, and the drive motor and ball screw are connected by a torque transmission means. Accordingly, resonance with frequency in the lower frequency region is prevented, thus making it possible to maintain a high level of locus accuracy of the robot arm.

Abstract: A contact detector for movable objects comprises two opposite circular plates in which a plurality of cylindrical depressed portions are equidistantly opened on the same circumferences from a common center axis of the two circular plates, respectively, a plurality of steel balls, having a diameter larger than the diameter of each depressed portion, inserted into corresponding depressed portions of the two circular plates, and hardened layers formed on the portions in contact with the steel balls of the circular plates by pressurizing two circular plates from the opposite sides of respective depressed portions. A portion of the surface of each steel ball is depressed into each recessed portion, and the one circular plate and the steel balls are pressed into contact with the other circular plate by an elastic member.