Abstract: An automatic device for changing an electric welding gun, operated by the arm (11) of a manipulator, in which two elements (10, 50), one carried by the manipulator arm and the other by the gun, can be connected together by the first element being made to approach and fit into the second; each element is provided with ducts (13) for passage of the liquid for cooling and controlling the opening of the electrodes (63); valve units (31) connect said ducts (13) to each other when the two elements (10, 50) are fitted together; the approach of the two elements is guided and checked, and hydraulically controlled hook portions (42, 71) lock together and separate the elements in accordance with the programming of the manipulator; each element is also provided with male cones (66) and female cones (16) provided on or in copper units (14) in order to fit into each other and establish electrical contact between the manipulator and gun.

Abstract: The electrical spot welding manipulator is assembled of a base, a rotary support on the base, an arm hinged to the support and rotatable at right angles to the support, a rotatable hollow member inside the arm, a column arranged inside the hollow arm for rotation about its axis, a working head mounted on the column and being rotatable about two secondary axes, movable welding grips mounted on the head, actuator elements, for activating respective movable members, and a welding transformer arranged in the arm and connected to the welding grips by flexible conductors.