SAFETY INTERLOCK SYSTEM FOR MICROWAVE OVENS

• US 3,816,688 A
• Filed: 03/01/1973
• Issued: 06/11/1974
• Est. Priority Date: 04/03/1972
• Status: Expired due to Term

• Current Assignee: Rex E. Fritts
• Original Assignee: Rex E. Fritts
• Inventors: Fritts, Rex E.
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Jaeger, Hugh D.
• Application Number:
  US05/337,256
• Time in Patent Office: 467 Days
• Field of Search: 219/10.55 317/4R,4A,16 340/275,421,274 335/160
• US Class Current: 219/723
• CPC Class Codes: H01H 47/002 Monitoring or fail-safe circuits
• CPC Class Codes: H05B 6/6417 Door interlocks of the microwave heating apparatus and related circuits

Abstract

A safety interlock system is disclosed for microwave ovens or other high voltage electrical apparatus incorporating sensor means for detecting any malfunction. Means are provided for interrupting line input power or actuating a failure indicating device or a combination of both. Thermally actuated means, such as bimetallic or meltable elements, as well as circuit breakers, relays and fuses are described. The sensor means are associated with each of the interlocks and do not carry regular equipment load current until such time as a malfunction of the companion interlock occurs. Replacement of the faulty equipment by authorized personnel and manual resetting of the interrupt or indicating means before the oven is energized again reduce the risk of accidental radiation, electrical shock or damage to the apparatus.

Claims

1. Microwave oven apparatus comprising:

a conductive enclosure having an access opening;

a door closing said access opening;

a microwave energy generator;

an electrical circuit for energizing said generator including safety interlock switch means;

said circuit including a voltage source;

sensor means for detecting the malfunction of said interlock switch with said interlock switch means normally closed and said sensor means normally open when said apparatus is operative; and

means operatively associated with said sensor means to deenergize said generator upon detection of an unsafe operating condition with both said interlock switch and sensor means in closed positions.

2. Microwave oven apparatus according to claim 1 and warning means for indicating the occurrence of said unsafe interlock switch and sensor means condition.