Welding apparatus

Claim 1

A WELDING HEAD FOR WELDING AN ENCLOSED UNIT HAVING A FLANGED HEADER ASSEMBLY AND A CORRESPONDINGLY FLANGED ENCLOSURE CAN AT THEIR RESPECTIVE ANGLES COMPRISING IN COMBINATION: A SUPPORT MEANS; A FIRST ELECTRODE AND A SECOND ELECTRODE ALIGNED AND ENGAGEABLE WITH EACH OTHER, SAID FIRST ELECTRODE RECIPROCALLY MOUNTED TO SAID SUPPORT MEANS AND COMPRISING A BASE PORTION WITH A CIRCULAR SHAPED CENTER PORTION HAVING A FREE END EXTENDING THEREFROM, SAID CENTER PORTION INCLUDING A DEPRESSION COMMENCING AT SAID FREE END AND A FACE PLATE MEMBER, SAID FACE PLATE MEMBER HAVING AN APERTURE LOCATED SUBSTANTIALLY CONCENTRIC WITH SAID DEPRESSION TO RECEIVE SAID HEADER ASSEMBLY AND SUPPORT SAID FLANGE THEREOF, SAID SECOND ELECTRODE FIXED TO SAID SUPPORT MEANS AND HAVING A CIRCULAR SHAPED PERIPHERY, A FLAT TOP SURFACE, AND HAWVING A NETWORK OF AIR PASSAGEWAYS EXTENDING THERETHROUGH, SAID TOP SURFACE INCLUDING A FIRST APERTURE LOCATED IN THE CENTER THEREOF AND A SET OF APERTURES LEADING INTO SAID NETWORK OF PASSAGEWAYS, SAID SET BEING SPACED EQUAL DISTANCE APART AND CONCENTRIC WITH SAID FIRST APERTURE; MEANS FIXED WITHIN AND RECEIVED BY SAID FIRST APERTURE TO RECEIVE SAID ENCLOSURE CAN AND SUPPORT SAID FLANGE THEREOF; A FLEXIBLE CIRCULAR WALL ENGAGEABLE WITH SAID SECOND ELECTRODE AND HAVING TWO ENDS, ONE END BEING FIXED TO SAID BASE PORTION AND THE OTHER END BEING FREE, A COMPRESSIBLE SECTION OF BELLOWS, AND A FLANGE, SAID FLANGE INCLUDING A WEDGE WITH A TAPERED CROSS-SECTION TO PROVIDE FLEXIBILITY AND A SEAL BETWEEN SAID WALL AND SAID SECOND ELECTRODE UPON BEING ENGAGED TO THEREBY FORM AN ENCLOSED CHAMBER ABOUT SAID FIRST ELECTRODE AND SAID TOP SURFACE, DRIVING MEANS SUPPORTED BY SAID SUPPORT MEANS AND OPERATIVELY CONNECTED TO SAID BASE PORTION TO MOVE SAID CIRCULAR WALL INTO ENGAGEMENT WITH SAID TOP SURFACE AND TO MOVE SAID FIRST ELECTRODE INTO WELDING ENGAGEMENT WITH RESPECT TO SAID SECOND ELECTRODE AND TO RESTORE THE SAME, EVACUATION MEANS COUPLED TO SID NETWORK PASSAGEWAYS FOR EVACUATING AIR FROM SAID CHAMBER, AND ENERGIZING MEANS TO ENERGIZE SAID ELECTRODES AND WELD SAID FLANGES TOGETHER AFTER SAID ELECTRODES MOVE INTO WELDING ENGAGEMENT.