GB1226538A - - Google Patents

Abstract

1,226,538. Making transformer cores; bonding; removing finished work. TELCON METALS Ltd. 2 Jan., 1969 [7 Nov., 1967], No. 50596/67. -Headings B3A, B3E and B3W. [Also in Division H1] In a method of making a laminated magnetic core, a strip of metallic material 2 is wound around a mandrel 3 and a reference groove 4 is cut approximately on the diameter of the coil. The strip is then unwound in steps and at the end of each step it is marked by a marking head 5. The position of the mark relative to the groove 4 is controlled to provide the required joint configuration in the finished core. Preferably, two heads 5<SP>1</SP>, 5<SP>11</SP> are used and the mandrel is rotated 180 degrees at each step. The angle α determines the angle at which the ends of the core halves interleave, the form of the joint being a cross. Three or more marking heads may be used where complex non-linear forms of interleave are required. The strip is then fed through straightening rolls 7, if necessary, and is cut by a guillotine tool 6. Individual strips are fed alternately into two stacks 9a, 9b by a divider 8. They are aligned on a vibrating bed, having a raised bead on one face which engages in the reference grooves. The stacks 9a, 9b are placed on a press 10 and pushed by a ram actuated block 11 into a tube 12 of rectangular cross-section, several pairs of stacks being pressed successively into the tube. The tube with the formed half cores and the blocks 11, which are detachable from the ram, are then heated to stress relieve the half cores. After heat treatment the half cores are pushed through the tube so that the back limbs of the lowermost pair of stacks protrude therefrom. The protruding parts are coated with adhesive by dipping in a tank 14, painting or spraying and when the adhesive has set, they are ejected from the tube, with the next pair similarly protruding. The blocks 11 are removed from the bonded half cores and any burrs removed. The strips are then lightly oiled and assembled into cores, normally by hand. A mating insert 16 and slot 17 may be provided in the core halves, in which case a third marking head will be required for marking the slot and insert.