Welding apparatus

Claim 1

A STEP WELDER COMPRISING A FIRST GUIDE, A CARRIER MOVABLE ON SAID GUIDE, A PAIR OF GUIDE MEANS ON THE CARRIER, ARMS OPPOSITELY MOVABLE ON SAID GUIDE MEANS, EACH OF SAID ARMS BEING ADAPTED TO CARRY AN ELECTRODE DEVICE TO AND FROM WORK TO BE WELDED, A COMPENSATING DEVICE ON SAID CARRIER HAVING MEANS ARTICULATED WITH SAID ARMS RESPECTIVELY TO EFFECT OPPOSITE RELATIVE MOVEMENTS THEREOF WHEN THE CARRIER IS ADVANCED ON SAID FIRST GUIDE AND ONE OF THE ELECTRODE DEVICES CONTACTS A PORTION OF WORK IN ONE PLANE, WHEREBY THE OTHER ELECTRODE DEVICE ADVANCES TO CONTACT A PORTION OF WORK IN ANOTHER PLANE, EXPANSIBLE FLUID CHAMBER MEANS HAVING RELATIVLEY MOVABLE FIRST AND SECOND PARTS, THE FIRST OF WHICH IS CONNECTED TO THE CARRIER TO MOVE IT TOWARD ENGAGEMENT OF THE ELECTRODE DEVICES WITH THE WORK, THE SECOND OF WHICH PARTS IS ARTICULATED WITH A REACTION MEMBER TO BE HELD BY IT AND TO MOVE IT, MEANS BIASING THE REACTION MEMBER NORMALLY TO PREVENT SUCH MOVEMENT, MEANS FOR FORCING FLUID INTO THE CHAMBER OF SAID EXPANSIBLE CHAMBER MEANS FIRST TO MOVE SAID FIRST PART FOR ENGAGEMENT OF THE ELECTRODE DEVICES WITH THE WORK AND THEN BY REACTION TO MOVE SAID SECOND PART TO ACTUATE THE REACTION MEMBER, AN ELECTRIC CIRCUIT INCLUDING THE ELECTRODE DEVICE AND THE WORK, A SWITCH IN THE CIRCUIT, AND MEANS CONNECTING THE REACTION MEMBER AND THE SWITCH TO CLOSE THE CIRCUIT WHEN THE REACTION MEMBER IS ACTUATED A CERTAIN AMOUNT IN ACCORDANCE WITH CONTACT REACTION PRESSURE BETWEEN THE ELECTRODE DEVICES AND THE WORK.