Robot welding toolholder

Industrial Robot

ISSN: 0143-991x

Article publication date: 1 February 2000



(2000), "Robot welding toolholder", Industrial Robot, Vol. 27 No. 1.



Emerald Group Publishing Limited

Copyright © 2000, MCB UP Limited

Robot welding toolholder

Robot welding toolholder

Keywords: Robots, Welding, Spotwelding, Grippers

Applicant: ASEA Brown Boveri (SE)Patent Number: US5931047Publication date: 3 August 1999Title: Industrial robot

The patent describes an invention to prevent leakage of electric current from a spotwelding gun through the robot. Such leakage currents may damage particularly the bearings for the movable arms of the robot, the damage appearing as craters in the bearing races. To insulate a welding gun it should be attached to the toolholder via blocks and/or plates of an insulating material which is resistant to deformation. However, the mechanical joint must withstand great loads. The object of the invention is to produce an industrial robot with a toolholder which eliminates these disadvantages. The toolholder is to exhibit an electrical insulation between the toolholder and the robot. The robot is to offer the user a toolholder to which tools of various kinds, and in particular a spotwelding gun, can be applied in a simple manner. This is achieved according to the invention by a robot with a toolholder which is characterized in that its turning disc is electrically insulated from the robot and by a method with the characteristic features including arranging the turning disc to be electrically insulated from the robot. A toolholder comprises a gear and a turning disc fixed to the output shaft of the gear. According to the invention a thin insulating layer is applied between the output shaft and the turning disc. The disc is fixed to the output shaft with a screw joint. The screws are threaded in the shaft journal and lock the disc to the shaft by means of insulating washers. Guide means of insulating material are applied in the screw holes through the disc so that the screws are kept isolated from the disc.

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