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:
May. 30, 1978
Filed:
Mar. 16, 1977
Masahiro Yanagi, Hirakata, JA;
Matsushita Electric Industrial Co., Ltd., Kadoma, JA;
Abstract
The present invention is an apparatus for detecting the breaking of a glass plate. The invention uses a piezoelectric element, a signal separating circuit and a gate circuit. The piezoelectric element converts the vibrations of the glass plate into an electrical signal. The signal separation circuit separates the electrical signal into two signal signal components. The first signal component has a frequency range of less than 50 kHz. The second signal component has a frequency component higher than 100 kHz. The gate circuit produces an output signal only when both of the signal components have a signal level higher than their respective predetermined levels. By simultaneous detection of both of the first and second signal components, erroneous indication of the breaking of a glass plate can be prevented.