Induction heating core structure and method of heating
AssigneeIllinois Tool Works Inc.
InventorRobert Louis Zirk, Sr.
Life of this patent
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Abstract
An induction heating coil and core structure which provides two distinct magnetic circuits, with the materials to be heated also forming a part of the circuits so that juxtaposed workpieces can be joined together with a layer of heat activatable adhesive by a unitary core structure. A pair of nested U-shaped cores have a differing number of exciter coil turns with at least one common turn wrapped about each of the members to produce a greater amount of flux density in one core than the other to effect a different heat rate between the workpieces which complete each magnetic circuit.
Claims7
A composite core and coil structure for use in heating workpieces by induction, including a first generally U-shaped core and a second generally U-shaped core nestably associated with the first core, exciter coil means wrapped about portions of each core providing at least one turn which simultaneously encircles portions of both cores, the coil means providing a predetermined number of turns about the first core different than the number of turns about the second core, the length of the legs portions of the first core are greater than the length of the leg portions of the second core.
A method of adhesively securing a first metallic workpiece of predetermined volume to a second metallic workpiece of a greater total volume, including the steps of placing the first workpiece on the second workpiece with a layer of heat activable adhesive therebetween, heating by induction, both workpieces simultaneously from a single side so that the faying surface of each will reach a predetermined temperature substantially simultaneously, wherein the induction heat is provided by a pair of nested U-shaped cores with an exciter coil wound about their bight portions so that the outermost core has more windings than the inner core, the outermost core legs contacting the second workpiece while the inner core legs contact the first workpiece whereby the second workpiece will be subjected to a greater amount of heating flux than the first workpiece.
Dependencies are inferred from the claim text.