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:
Nov. 15, 1977
Filed:
Jul. 16, 1976
James C Durand, Peoria, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
To detect and record the highest operating temperature range which occurs in an engine, transmission, implement hydraulic system or the like during an extended period of time, an indicator device is adapted to be mounted in thermal contact with a liquid coolant flow, lubricant flow or the like of the apparatus. The device has a housing containing a plurality of electrical resistor segments connected in series between an external electrode and the housing. A plurality of temperature-sensitive switches are arranged to short out successive ones of the resistor segments upon the occurrence of successively higher predetermined temperatures. The maximum temperature range which has been reached over an extended period of operating time may then be determined by using an ohmmeter to measure the electrical resistance between the electrode and the housing since the shorting out of successive ones of the resistor segments, upon the occurrence of successively higher temperature ranges, progressively reduces the electrical resistance in the circuit. The temperature-sensitiveswitches may be a series of springs each initially held in a compressed state by a body of wax wherein the spring expands to short out the associated one of the resistor segments upon melting of the wax and wherein the wax bodies associated with successive ones of the springs melt at progressively higher temperatures.