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:
Feb. 19, 1991
Filed:
Jul. 14, 1989
David W Vrona, Glen Ellyn, IL (US);
Manley S Keeler, Naperville, IL (US);
Ohio Mattress Company Licensing & Components, Chicago, IL (US);
Abstract
A protection device for a waterbed protects the water bladder and water heater from damage due to overheating when a dangerous condition, such as an insufficient level of water within the bladder or an element of the waterbed surroundings interposed between the bladder and the water heater, arises. The protection device employs a detector in the form of two capacitance plates placed adjacent to the water bladder and connected to a circuit which is operative to prevent power from being supplied to the water heater upon detection of a dangerous condition. The capacitance of the detector plates varies with the level of the water within the bladder and with the presence of a surrounding element between the bladder and heater.