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:
Dec. 20, 1994
Filed:
Sep. 29, 1992
Jeffrey P Bledsoe, Weatherford, TX (US);
William M Carra, Fort Worth, TX (US);
General Dynamics Corporation, Fort Worth, TX (US);
Abstract
A fail-safe circuit for preventing an inadvertent communication of a signal from an input terminal to an output terminal includes a series switching network electrically connected between the input terminal and the output terminal. The series switching network contains two switching circuits electrically connected in series. One switching circuit is an electrical switching circuit and the other is an electromechanical switching circuit. The switching circuits are chosen such that defects causing the electrical switching circuit to short circuit do not affect the electromechanical switching circuit and defects causing the electromechanical switching circuit to short circuit do not affect the electrical switching circuit. The fail-safe circuit also includes circuitry for preventing inadvertent communication of the signal from the input terminal through the series switching network to the output terminal when one of the switching circuits is in a short circuited state or condition. This circuitry includes a circuit system for detecting a short circuit condition in the series switching network. Also included is another circuit system that is responsive to a short circuit condition within the series switching network for preventing the closing of the switching network to prevent communication of the signal from the input terminal through the series switching network to the output terminal.