Apparatus for making a transformer core of non-circular cross-section

Apparatus for making a transformer core having a quadrilateral cross-section, comprising:

• means for forming a packet of amorphous metal core strips,
• a stationary, collapsible mandrel having a cross-sectional perimeter of quadrilateral shape with curved corner regions,
• means for locating the packet beneath said mandrel,
• wrapping means for wrapping packets of amorphous metal core strips comprising:
• means for lifting the packet against a bottom of the mandrel,
• a pair of rollers yieldably biased to a neutral position suitable for engaging an underside of the packet,
• means for raising said rollers from a lower position to an upper position whereby said rollers follow the contour of said mandrel periphery to wrap the packet therearound so that opposite ends of the packet form a joint,
• holding mean having pressure pads movable into engagement with the wrapped packet to hold the packet against the mandrel, said holding means including pressure pads with concavely curved pressing surfaces for pressing against at least two corner regions of the wrapped packet,
• means for returning said rollers to said lower portion to receive successive packets, and
• retracting means for momentarily retracting said pressure pads to permit said return travel of said rollers to said lower position, and
• collapsing means for collapsing said mandrel to facilitate the removal of a core which has attained a desired thickness.