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US 6,297,477 B1Granted
Electric cooking and toasting apparatus and electric elements therefor
AssigneeDualit Limited
InventorsLeslie Alexander Gort-Barten, Brian Milton
Life of this patent
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AssigneeDualit Limited
InventorsLeslie Alexander Gort-Barten, Brian Milton
Estimating the term…
An electric heating element (11) in which electrically conductive tape (23) is wound on a non-electrically conductive former (12) and the tape is completely covered by covers (30) of electrically non-conductive but heat conductive material secured to the former. Preferably the covers and former are of Mica or Micanite. The covers are secured to the former by channel sectioned strips (31) along opposite side edges and by fastening eyelets (26) extending through the covers and former intermediate the edges. For use in an upright toaster the tape is wound continuously round the former with each run thereof extending between the grooves in the opposite side edges of the former, the grooves in the upper portion being spaced from one another by 4.6 to 7 mm while the grooves in the lower portion of the former are spaced by a smaller distance in the range 3.6 to 5 mm. For use in a conveyor toaster the runs adjacent the sides of the conveyor are more closely spaced than those in the center. The invention extends to toasters and other cooking or heating apparatus incorporating such elements.
An electric heating element (11) in which electrically conductive tape (23) is wound on a non-electrically conductive former (12) and the tape is completely covered by a cover or covers (30) of electrically non-conductive but heat conductive material secured to the former by channel sectioned strips (31) extending over the edges of the former and cover or covers on at least two opposite sides (13, 14) and by fastening means (26) extending through the cover or covers at at least two positions intermediate those sides and not contacting the tape.
An electric element for a toaster comprising a former (12) of electrically insulating but heat conductive material and electrically conductive tape (23) wound spirally on the former in a plurality of runs extending between grooves (15) in opposite side edges (13, 44, 59) of the former or parts (52, 53) of the former, the runs in the upper portion being spaced from one another by a distance in the range 4.6 to 14 mm while the runs in the lower portion of the former are spaced from one another by a smaller distance in the range 3.6 to 10 mm, the length of the tape being in the range 5 to 10 meters and the tape being selected to give a watt density equal to or less than 3 watts per centimeter2.
A method of manufacturing an element comprising a former wound with conductive tape, on or both sides of which former are covered by a cover of electrically non-conductive but heat conductive material, the former being assembled from two parts (52, 53), which comprises:
Dependencies are inferred from the claim text.