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:
Jan. 16, 1979
Filed:
May. 09, 1977
Kristupas Daugirdas, Wilmette, IL (US);
Samir Elguindy, Bensenville, IL (US);
Vapor Corporation, Chicago, IL (US);
Abstract
A pneumatic powered door operator including a pneumatic differential engine with an output shaft having a slide bar applying driving action through a roller to a multiplying lever wherein the multiplying lever is pivotally mounted at one end and provided with a roller at the other end and linkage means for interconnecting the multiplying lever to a slidable door. An electropneumatic control circuit controls the operation of the engine and includes a pneumatic spring arrangement which allows manual operation of the door during electrical failure with air available while being capable of maintaining the door in a closed position when not manually actuated.