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:
Oct. 14, 1986
Filed:
Aug. 08, 1984
John C Paine, Chardon, OH (US);
Caterpillar Industrial Inc., Mentor, OH (US);
Abstract
Electronic hourmeter devices having non-volatile memories are useful, for example, in industrial vehicles. Advantageously, such non-volatile memories should be free from a need for battery back-up systems and should minimize the number of changes of the internal memory registers. The subject electronic hourmeter apparatus includes both a dynamic memory device and a non-volatile memory device. Data is maintained in each of the memory devices and memory bit changes are minimized by utilizing a gray coded binary representation of a portion of the data and by systematically altering the addressed memory location of a portion of the data in response to one of the stored data values. Data storage occurs both periodically and in response to disconnection of the vehicle battery. Thus, the disclosed electronic hourmeter apparatus 10 advantageously maintains the integrity of the stored data, minimizes the number of bit changes that occur in the non-volatile memory device, and avoids the need for a battery back-up.