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. 09, 1980
Filed:
May. 18, 1978
Applicant:
Inventor:
Michael G Smart, Sunbury on Thames, GB;
Assignee:
G. V. Planer Limited, Sunbury on Thames, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H / ; H03K / ;
U.S. Cl.
CPC ...
307360 ; 3072 / ; 307311 ; 340661 ; 361 90 ; 361187 ;
Abstract
A fail safe control circuit in which an input signal for initiating control of a potentially dangerous system is amplified only if it lies between given limits and also only if electrical power is being supplied to the system. The outputs of the amplifiers are monitored to check their correct operation, and two independent optical output signals obtained therefrom. The optical signals are arranged independently to operate switches in the system, such that both switches have to operate before the system can be actuated.