Induction heating unit for heat bonding a lid having a metallic layer to a container.

摘要

This relates to an apparatus for heat bonding a lid having a metallic layer to a plastic container. The container, filled with a product, is seated in a nest and a lid is seated in place thereon. There is at least one corner on the lid and projecting from that corner is a pull tab. An induction heating unit is associated with the lid and presses it tightly against the container while inducing electrical energy under controlled conditions into the metal layer. The induction heating unit is provided with a specific arrangement of ferrite members for controlling the induction of current into the metallic layer. The ferrite parts in conjunction with the induction coil serve to concentrate the induced electrical energy into substantial alignment with the induction coil notwithstanding the fact that there is a corner and there is projecting from the corner of the lid a pull tab.