Welding of strips

Claim 1

MEHTOD FOR WELDING AN ELONGATED EDGE OF ONE METAL PORTION TO AN ELONGATED EDGE OF ANOTHER METAL PORTION, WHICH COMPRISES: CLAMPING SAID PORTIONS RESPECTIVELY IN POSITION WITH SAID EDGES IN SUBSTANTIALLY PARALLEL CLOSELY-SPACED RELATION; CONDUCTING HEATING CURRENT FROM A SOURCE THEREOF HAVING A FREQUENCY OF THE ORDER OF 100,000 CYCLES PER SECOND OR HIGHER ONTO THE ELONGATED EDGE OF THE FIRST OF SAID PORTIONS TO FLOW THEREALONG; THENCE CONDUCTING SUCH CURRENT OVER TO THE OTHER OF SAID ELONATED EDGES AND BACK THEREALONG AND THENCE BACK TO THE SOURCE; CAUSING SAID CURRENT TO BE CONCENTRATED TO SUBSTANTIALLY A UNIFORM DEGREE ALONG SAID EDGE AND AVOIDING THE TENDENCY OF THE CURRENT TO DISTRIBUTE ITSELF FURTHER AWAY FROM THE MID-PORTION OF SAID EDGES THAN AT OTHER PORTIONS, BY PLACING MAGNETIC MASSES HAVING A LOW LOSS FACTOR AND HIGH VOLUME RESISTIVITY IN POSITION CLOSELY SPACED FROM SAID MEMBER AND SOMEWHAT SPACED BACK AWAY FROM SAID EDGES RESPECTIVELY, THEREBY TO INCREASE THE IMPEDANCE TO THE CURRENT FLOWING AT SAID FREQUANTLY ALONG PATHS SPACED BACK AWAY FROM THE EDGES AND HENCE CAUSING SUCH CURRENT TO BE CONCENTRATED ON THE EDGES AS AFORESAID; DISCOUNTINUING THE CURRENT FLOW WHEN THE OPPOSED SURFACES OF SAID EDGES BECOME HEATED TO WELDING TEMPERATURE; AND FORCING AT LEAST THE ADJACENT PARTS OF SAID METAL PORTIONS INTO RELATIVE POSITIONS TO BRING THE THUS-HEATED OPPOSED SURFACES INTO CONTACT FOR WELDING SAME TOGETHER WHILE APPLYING CONFINING PRESSURE TO THE OPPOSITE SURFACES OF SAID PORTIONS RESPECTIVELY ALONG THE ZONE OF THE WELD.