Microwave oven control system

• US 4,158,759 A
• Filed: 09/16/1977
• Issued: 06/19/1979
• Est. Priority Date: 09/16/1977
• Status: Expired due to Term

• Current Assignee: Ranco Incorporated of Delaware (Schneider Electric SE)
• Original Assignee: Teccor Electronics Incorporated (Teccor)
• Inventors: Mason, William B.
• Primary Examiner(s): Grimley, Arthur T.
• Application Number:
  US05/833,907
• Time in Patent Office: 641 Days
• Field of Search: 219/10.55 B, 219/10.55 R, 219/506, 340/366 G, 340/365 R, 340/365 A, 340/365 S, 126/197, 99/325
• US Class Current: 219/720
• CPC Class Codes: G05B 19/104 characterised by physical layout of switches; switches co-operating with display; use of switches in a special way
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G05D 23/20 with sensing elements having variation of electric or magnetic properties with change of temperature G05D23/13 takes precedence
• CPC Class Codes: H05B 6/666 Safety circuits emergency protective circuits in general H02H
• CPC Class Codes: H05B 6/687 for cooking

Abstract

An electronic display having a plurality of digit positions is employed in conjunction with a keyboard to enter data for controlling the operation of a microwave oven. Each digit position of the display is individually responsive to a corresponding key of the keyboard, whereby actuating such key causes its display digit to run repetitively through a numerical sequence without carrying over into other display digits. Upon stopping actuation of such key, its display digit stops on the numeral displayed at that moment. Other digits of the display may be similarly loaded with data, whereby the fully loaded display represents a control parameter, such as cooking time. Actuating a start key permits the oven to carry out a cooking program in accordance with the data thus entered into the display.

Claims

1. A microwave oven control system comprising:

a keyboard having a plurality of actuable keys for receiving user commands, the actuable keys including a plurality of digit entry keys for entering numerical operating data into the system,

an electronic display having a plurality of digit positions for displaying the numerical operating data, each digit position being capable of selectively displaying the ten decimal numerals in response to actuation of a corresponding digit entry key, each digit position being slewed through a count sequence of some or all of the ten decimal numerals as long as the corresponding digit entry key is held actuated, whereby numerical operating data is entered into the display by holding one or more of the digits entry keys actuated until the desired numerals are displayed by the digit positions of the display, and

control circuitry responsive to the commands from the keyboard for controlling the operation of the system and outputting data to the display.

2. The system of claim 1 further comprising a time register for storing a time setting entered into the display by separately slewing at least one digit position through a count sequence to a desired numeral.

3. The system of claim 2 wherein the digit positions of the display are four in number, each of which is slewed through a count sequence of all ten of the decimal numerals with continuous rollover and without carryover between digit positions upon actuation of the corresponding digit entry key, the two least significant digits representing seconds and the two most significant digits representing minutes.

4. The system of claim 1 further comprising a temperature register for storing a temperature setting entered into the display in degrees Fahrenheit, and means for detecting when a temperature probe is installed in a receptacle and thereupon causing the system to operate in a temperature mode.

5. The system of claim 4 further comprising means for entering a temperature setting during operation in the temperature mode, wherein the least significant digit position of the display is slewed through a sequence alternating between the numerals "0" and "5", wherein the next to least significant digit position of the display is slewed through a count sequence of all ten of the decimal numerals, and wherein a most significant digit is locked on the numeral "1", whereby a temperature setting between 100°

F. and 195°

F. in increments of 5°

F. can be entered.

6. The system of claim 1 further comprising a power-level register, and means for entering duty-cycle data into the power-level register.

7. The system of claim 6 wherein the least significant digit position of the display is locked on the numeral "0" and the next to least significant digit position of the display is slewed through a count sequence of all ten of the decimal numerals, whereby a percentage duty cycle can be entered into the power-level register in multiples of ten between zero and 100 percent.

8. The system of claim 6 wherein the control circuitry further comprises means for automatically switching the system to a reduced power level for holding an item in the oven warm for a predetermined period of time after completion of a cooking cycle.

9. The system of claim 1 wherein the actuable keys of the keyboard include a time/temp key, which when actuated in a time mode permits entry of a time setting into the display, and which when actuated in a temperature mode permits entry of a temperature setting into the display.

10. The system of claim 9 wherein the control circuitry includes means for detecting the presence or absence of a temperature probe in a receptacle and accordingly causing operation in either the temperature mode or the time mode.

11. The system of claim 1 wherein the control circuitry includes a time register and a power-level register, and wherein the actuable keys of the keyboard include a first key for entering a time setting into the time register, a second key for entering a duty-cycle setting into the power-level register, and a third key for starting a cooking cycle.

12. The system of claim 11 wherein the control circuitry further includes means in communication with the keyboard and the display for alternatively displaying the state of the time register upon actuation of the first key or the state of the power-level register upon actuation of the second key without modificaiton or interruption of the cooking cycle.

13. The system of claim 1 wherein the control circuitry includes a temperature register, and wherein the actuable keys of the keyboard include a first key for entering a temperature setting into the temperature register and a second key for starting a cooking cycle.

14. The system of claim 13 further comprising means in communication with the control circuitry for measuring the temperature of an item being cooked, and the control circuitry further includes means in communication with the keyboard and the display for alternatively displaying the state of the temperature register upon actuation of the first key or the measured temperature of the item being cooked upon actuation of the second key without modification or interruption of the cooking cycle.

15. The system of claim 1 wherein the actuable keys of the keyboard include a clear key for blanking the display and resetting registers of the control circuitry.

16. A method of controllably cooking an item in a microwave oven, comprising the steps:

(a) actuating a first control key to enable a storage register to receive data entry,

(b) separately slewing a plurality of digit positions of a display and simultaneously loading a control parameter corresponding thereto into the enabled storage register, and

(c) actuating a second control key to initiate a cooking cycle controlled in accordance with the stored control parameter.