Abstract: An apparatus for receiving and holding tools, specifically resistance welding units, carried by a robot programmed to execute certain movements including the placing of these tools at a specific location, including a base, for a vertical frame having a series of radial supports which can be rotated about a vertical axis and immobilized in positions in which the radial supports are disposed opposite various work stations, and respective mechanisms for decoupling a tool from the robot and for coupling a tool to the robot, so that at any one time the robot only carries one tool while other tools which may be used by the robot are freely available for repair and maintenance without interrupting the operation of the robot.

Abstract: A welding apparatus includes an improved transformer having a U-shaped secondary winding movable therein and guided by means external to the transformer. One leg of the U-shaped winding is flexibly connected to a first welding electrode carried by the piston rod of a jack having a jack body and piston adapted for movement relative to one another. The other leg of the winding is rigidly connected to a second welding electrode which is also rigidly secured to the jack body. The jack is movably mounted on guide means external to the transformer. Thus, as the second electrode is moved during a welding operation, the secondary winding is guided within the transformer by the movement thereof.A method of welding includes moving the first electrode toward a workpiece so as to contact the same and thereafter moving the second electrode to clamp the workpiece for welding, the secondary winding being guided by the movement of the second electrode.

Abstract: A scissors-type electric welding apparatus is provided which has a transformer, a pair of electrodes, a pair of first arms movably mounted on the transformer, an electrically insulated articulation shaft, and a pneumatic jack. A pair of second arms are pivotably connected to the articulation shaft. The second arms support the electrodes on one end and are connected to the jack on the other end in order to move the electrodes apart to position the electrodes for welding workpieces. The electrodes are electrically connected to the first arms through the second arms. Each second arm includes a contact member mounted on the articulation shaft. Each first arm includes a free end which carries a contact shoe for interacting with a contact member. A biasing member is provided for urging the contact shoes against the contact members.

Abstract: Interposing a coating-compatible strip material between a coated plate to be welded and a welding electrode that contacts that plate during the welding operation so that a coating-compatible film is applied to the plate during the welding process to prevent the removal of the protective coating of the plate. A device for performing the process includes support means for supporting a supply of strip material and guides for interposing the strip material between the plate and the welding electrode that contacts that plate during the welding operation. The strip material may be contained in a cassette which is adapted to be attached to the device.