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:
Mar. 16, 1993
Filed:
Mar. 23, 1992
James A O'Brien, II, Burbank, CA (US);
Thomas Industries, Inc., Los Angeles, CA (US);
Abstract
A device for controlling swinging doors utilizing an externally powered motor to compress a spring during door opening to store energy in the spring. The motor is not used to open the door, but only to compress the spring, thereby utilizing a minimum amount of electrical energy and allowing for a very easy opening of the door. The motor acts as a generator during the closing of the door with generated electrical energy fed back to the motor to retard rotation of the rotor, providing a brake on the closing movement of the door. The feedback circuitry includes a switch for varying the braking during the final degrees of closing movement as well as a variable setting device allowing control of braking force.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile