The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 04, 1999
Filed:
Nov. 17, 1997
Richard Charles Scott, Stourport-on-Severn, GB;
Ceramaspeed Limited, , US;
Abstract
A method is described of processing an electrical signal output from a sensor coil located in an electric heater for use under a cook top in a cooking appliance. The sensor coil is employed to operate a switch to switch on and off a heating element in the heater in accordance with placement and removal of a cooking utensil on and from the cook top. The sensor coil is arranged in the heater within magnetic influence of the electrical heating element, the heating element comprising a material which is ferromagnetic below and substantially non-ferromagnetic above a predetermined temperature within an operating temperature range of the heater. The occurrence of an increase in output signal level from the sensor coil is detected and closure of the switch is effected. Subsequently, the occurrence of a decrease in output signal level from the sensor coil is detected and opening of the switch is effected. The switch is opened for a predetermined period and closure of the switch means is subsequently effected unless within the predetermined time period a further decrease in output signal level, consecutive with the previous decrease in output signal level, is detected.