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:
Sep. 26, 1978
Filed:
Jun. 08, 1976
Jan Olov Appelquist, Norrkoping, SE;
Conny Holger Lindwall, Norrkoping, SE;
U.S. Philips Corporation, New York, NY (US);
Abstract
A safety interlock system for microwave ovens comprising first and second interconnected switches activated by the oven door. Each switch has make-and-break contacts. The first switch interrupts the current to the microwave source when the door is opened and the second switch monitors the operation of the first switch. The switches are connected in series with a fuse so that a malfunction of either of the switches makes the oven immediately unusable. A delay element is connected within one switch and the first switch is arranged to operate before the second switch when the door is initially opened. The delay element is a negative temperature coefficient (N.T.C) resistor.