[54] INDUCTION HEATING COIL
[75] Inventor: Mitsuyuki Kiuchi, Minoo, Japan
[73] Assignee: Matsushita Electric Industrial Co., Ltd., Kadoma, Japan
[21] Appl. No.: 133,685
[22] Filed: Mar. 25, 1980
[30] Foreign Application Priority Data
Apr. 4, 1979 [JP] Japan 54/44205(U]
[51] Int. CI.' H05B 5/04
[52] U.S. CI 219/10.49 R; 219/10.79;
336/232
[58] Field of Search 219/10.49 R, 10.79,
219/10.75, 10.77, 464; 336/84 R, 205, 223, 232,
60; 13/26
[56] References Cited
U.S. PATENT DOCUMENTS
3,704,357 11/1972 Mouein 219/10.79
3.781.503 12/1973 Harnden et al 210/10.49
3.781.504 12/1973 Harnden, Jr 219/10.49
3,786,219 1/1974 Kornrumpf et al 219/10.49
3,786,220 1/1974 Harnden, Jr 219/10.49
3,809,846 5/1974 Baumgartner et al 219/10.79
3,814,888 6/1974 Bowers et al 219/10.49
4,029,926 6/1977 Austiw 219/10.49
4,092,511 5/1978 Austiw 219/10.49 R
Primary Examiner—Volodymyr Y. Mayewsky Attorney, Agent, or Firm—Wenderoth, Lind & Ponack
[57] ABSTRACT
An improved flat induction heating coil for a cooking apparatus of the type in which an electrically conductive cooking utensil is heated according to the principle of electromagnetic induction. To provide a substantially uniform magnetic flux density distribution in the induction coil constituting a part of the cooking apparatus and, hence, a uniform temperature distribution across the bottom of the cooking utensil, a refractory insulating material is wound adjacent inner turns of the coil to provide a comparatively larger winding pitch for said inner turns than for outer turns. This arrangement makes for a flattened temperature profile and eliminates an uneven cooking of food.
4 Claims, 6 Drawing Figures
