Secondary circuit and timing device for appliance

Abstract

A circuit configuration is disclosed for use in an appliance includes a power switch configured to open and close a first group of electrical contacts, where the contacts while closed cause the appliance to energize upon a user initiating a use of the appliance. The circuit configuration also includes a primary timing device electrically connected to the first group of electrical contacts, the primary timing device being actuated upon energization of the appliance and the primary timing device being configured to de-energize the appliance after a first time period by opening the first group of electrical contacts. The circuit configuration also includes a secondary timing device electrically connected to the power switch by a second group of electrical contacts, where the secondary timing device is configured to de-energize the appliance after a second time period, where the second time period is set based on the first time period.

1 .- 20 . (canceled) 
     
     
         21 . A control system for an appliance comprising:
 a power circuit having a first power switch with a first set of electrical contacts that are closed to energizer the power circuit, the electrical contacts of the power switch also configured to selectively provide an electrical connection from the power circuit to energize a heating element;   a first timing circuit connected with the power circuit, the first timing circuit energized when the power circuit is energized and configured for controlling a heating time period of a food product, and the first timing circuit configured to send a timer signal for causing the power circuit to de-energize at an expiration of the heating time period; and   a second timing circuit connected with the power circuit in parallel with the first timing circuit, the second timing circuit energized when the first timing circuit is energized and configured for timing a secondary time period that is at least as long as the heating time period, and the second timing circuit configured to send a signal for causing the power circuit to de-energize at an expiration of the secondary heating time period.   
     
     
         22 . The control system of  claim 21 , wherein the first timing circuit and the second timing circuit each comprise an application specific integrated circuit. 
     
     
         23 . The control system of  claim 21 , wherein the heating time period is configurable by a user. 
     
     
         24 . The control system of  claim 21 , wherein the secondary heating time period is set to be a maximum time period setting of the appliance. 
     
     
         25 . The control system of  claim 21 , wherein the first timing circuit is operatively connected with the first power switch for de-energizing the power circuit by opening the first power switch. 
     
     
         26 . The control system of  claim 25 , wherein the second timing circuit is operatively connected with a second power switch that is connected in series with the first power switch for de-energizing the power circuit by opening the second power switch. 
     
     
         27 . The control system of  claim 21 , wherein the opening of either of the first and second power switches de-energizes the power circuit. 
     
     
         28 . The control system of  claim 21 , wherein the first timing circuit is selected from the group consisting of: a resistor-capacitor (RC) circuit, an application-specific integrated circuit, and a transistor based timing circuit. 
     
     
         29 . The control system of  claim 21 , wherein the second timing circuit is selected from the group consisting of: a resistor-capacitor (RC) timing circuit, an application-specific integrated timing circuit, and a transistor based timing circuit. 
     
     
         30 . A method for controlling a heating time period by an appliance, comprising:
 closing a power switch to energize an appliance by a power circuit, wherein energizing the power circuit includes energizing a heating element of the appliance;   activating two parallel timing circuits upon closing the power switch and energizing the power circuit, wherein the two parallel timing circuits are each connected to the power circuit, and wherein each timing circuit is configured to individually send a timing signal to de-energize the power circuit and thus the heating element; and   de-energizing the power circuit at the receipt of a timing signal from one of the two parallel timing circuits.   
     
     
         31 . The method of  claim 30 , wherein each timing circuit of the parallel timing circuits is selected from the group consisting of: a resistor-capacitor (RC) circuit, an application-specific integrated circuit, and a transistor based timing circuit. 
     
     
         32 . The method of  claim 30 , further including a step of setting a first time period by a user for a first timing circuit of two parallel timing circuits and for de-energizing the heating element at the expiration of the first time period. 
     
     
         33 . The method of  claim 32 , wherein the first time period is used to determine a second time period for a second timing circuit of the two parallel timing circuits. 
     
     
         34 . The method of  claim 33 , wherein the second time period is determined to be at least as long as the first time period. 
     
     
         35 . The method of  claim 34 , wherein the second time period is set to be a maximum time period setting of the appliance. 
     
     
         36 . The method of  claim 30 , wherein the step of de-energizing the power circuit comprises energizing a relay to break the power circuit from the heating element. 
     
     
         37 . The method of  claim 30 , wherein the step of closing the power switch comprises moving an element of the appliance to cause the power switch to close. 
     
     
         38 . The method of  claim 37 , wherein the moving element comprises a food holding carriage that is held in a heating position by an electromagnet that is also operatively connect with the power circuit.