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:
Jun. 28, 1994
Filed:
Apr. 06, 1992
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A device for detecting a change in internal pressure of a cylinder includes a cylinder head, an ignition plug threadingly fitted into a plug insertion hole of the cylinder head. An annular piezoelectric sensor is secured in the plug insertion hole by screwing the plug into the insertion hole. The sensor has such an outer periphery that, when the ignition plug is screwed into the plug hole, a part of the outer periphery of the sensor placed is brought into engagement with an inside periphery of the plug hole and is thereby prevented from being further rotated in the screwing direction. By using a gasket having the same relative shape to the periphery of the plug insertion hole as that of the above sensor, rotation of the sensor can be prevented even when the sensor does not have such a relative shape.