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. 15, 1985
Filed:
Jun. 09, 1982
Rudiger F Stillfried, Barsinghausen, DE;
Gunter Seegers, West Bloomfield, MI (US);
Gunter Sebesta, Hemmingen, DE;
WABCO Fahrzeugbremsen GmbH, Hanover, DE;
Abstract
Pressurization of closing and opening chambers of a door operator is controlled by first and second magnet valves coupled to the source of air. These valves are alternately energized by a switching network, e.g., a flip-flop, when sequentially actuated to close and open the door. The second magnet valve is biased to its vent position but the first valve is operated to its vent position by air through a double check valve when the second magnet valve is energized. Emergency and choke valves are inserted in series in the air supply to the magnet valves and normally pass air without restriction. Operation of the emergency valve, e.g., door blocked, shuts off air from the magnet valves and diverts that air to inhibit all output from the switching network and, through the check valve in opposite position, to operate the first magnet valve to vent position. Door operation is halted in position. Shortly the choke valve, because of the venting of both magnet valves, shifts from non-choke to choke position to restrict flow of air when the emergency valve is restored to normal. Restoration of door operation, by switch network actuation at the end of the emergency, is thus initially at a restricted rate.