Patent attributes
An automatic welding machine, comprising a supporting frame and a tensioning device for reversibly joining at least two opposing booms to one another and applying a tension force between these, having an open position in which the opposing booms are separated from one another by a gap and a closed position in which the opposing booms are joined to one another and braced with respect to one another. One boom is mounted in a torsion-proof manner on the tensioning device and is pivotable in relation to the other boom and can be moved out of the open position into the closed position by the pivoting of the tensioning device. The tension force is generated by way of a spring-loaded element disposed on the tensioning device, wherein the spring-loaded element, at one end, is rigidly connected to a supporting element of the tensioning device and, at the other end, is pivotably mounted on the supporting frame by way of a double swivel joint, and the spring-loaded element is tensioned by the pivoting of the double swivel joint out of the open position into the closed position, whereby a torque is applied onto the pivotable boom.