Method of making a two-piece frame for dynamo-electric machines

Claim 1

IN METHOD OF FABRICATING A TWO-PIECE MAGNETIC FIELD MEMBER FOR A DYNAMO-ELECTRIC MACHINE CONSISTING OF TWO TELESCOPING CONCENTRIC TUBULAR MAGNETIC MEMBERS, INCLUDING AN INNER AND AN OUTER TUBULAR MEMBER, COMPRISING FABRICATING THE INNER SUPPORTING MEMBER FROM A FLAT CONTINUOUS STRIP OF RELATIVELY THIN MAGNETIC MATERIAL WHEREIN APERTURES ARE PUNCHED AT PREDETERMINED LOCATIONS, FORMING THE PUNCHED FLAT STRIP INTO TUBULAR CONFORMATION, WELDING THE CONFRONTING EDGES OF THE TUBULAR CONFORMATION OF FORM A LONGITUDINAL SEAM, CUTTING AN INNER TUBULAR FRAME MEMBER FROM THE TUBULAR CONFORMATION OF THE ROLLED UP STRIP, EXPANDING THE INNER DIAMETER OF SAID TUBULAR MEMBER TO A PREDETERMINED DIMENSION, FABRICATING THE OUTER MAGNETIC TUBULAR MEMBER FROM A RELATIVELY THICK FLAT STRIP OF MAGNETIC MATERIAL HAVING APERTURES PUNCHED THEREIN AT PREDETERMINED LOCATIONS, CUTTING A PREDETERMINED LENGTH OF SAID THICK STRIP AND ROLLING SAID SEVERED PORTION INTO TUBULAR CONFORMATION HAVING A PREDETERMINED DIAMETER RELATIVE TO THE INNER MEMBER WITH AN AIR GAP BETWEEN THE CONFRONTING ENDS TO FORM THE OUTER TUBULAR MEMBER, MOVING THE INNER AND OUTER MEMBERS LONGITUDINALLY TOGETHER INTO CONCENTRIC TOUCHING RELATION TO SLIGHTLY EXPAND THE OUTER MEMBER WITH SOME OF THE PREPUNCHED APERTURES IN THE TWO MEMBERS IN ALIGNMENT, AND PROVIDING HOLDING MEANS IN SOME OF THE ALIGNED APERTURES TO HOLD THE TWO MEMBERS TOGETHER.