Light sensitive control for toaster
AssigneeBlack & Decker Inc.
InventorDuc Hoang Tran
Life of this patent
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Abstract
In a toaster, a system is constructed to vary the duration of the toasting cycle. An RC network provides an oscillating signal to a counter, which upon the required number of oscillations being counted, triggers a transistor switch. The switch energizes the main solenoid switch which in turn deactivates the heating elements of the toaster. The RC network of the system comprises a variable resistor which may be manually operated, a heat sensitive resistor, and a light sensitive resistor.
Claims7
In an appliance for toasting bread or other pastries by the energization of heater elements within a toasting compartment, a control system for controlling the duration of the toasting cycle comprising:
- a power supply for converting line voltage to a low voltage suitable for providing power to the components of the control system;
- an RC network connected to the power supply for generating an oscillating signal used to time the duration of the toasting cycle;
- a counter connected to receive the oscillating signal and to generate a switching signal upon counting a predetermined number of oscillations;
- a transistor switch connected to turn off the toasting cycle in response to the switching signal;
- said RC network having a compensating circuit for varying the frequency of the oscillating signal further comprising:
- a manually adjustable resistor for setting the duration of the toasting cycle by the operator;
- a heat sensitive resistor responsive to the heat present in the toast compartment to increase the frequency of the oscillating signal;
- a light sensitive resistor responsive to the light emitted from the energized heater elements to increase the frequency of the oscillating signal;
- and
- means operatively associated with the heater elements to collect light emitted thereby and transmit said light to the light sensitive resistor.
A method of controlling the duration of the toasting cycle of an electric toaster having heating elements within a toasting compartment and wherein the time is set by the frequency of the output signal of an RC network comprising the steps of:
- establishing an initial toasting cycle through manual adjustment of the resistance of the RC network;
- varying the frequency of the output signal of the RC network in response to the heat in the toasting compartment through the use of a heat sensitive resistor;
- and
- varying the frequency of the output signal of the RC network in response to the intensity of the light emitted from the heating elements.
Dependencies are inferred from the claim text.