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:
Aug. 31, 2004
Filed:
Apr. 23, 2002
Phillip McCartney, Belvidere, IL (US);
Robert E. Dutka, Glen Ellyn, IL (US);
Andrew Gavel, Suffolk, NY (US);
William Chen, Queens, NY (US);
Robert J. Olmsted, Wood Dale, IL (US);
The Chamberlain Group, Inc., Elmhurst, IL (US);
Abstract
A cable tension sensing apparatus is mounted on a wall having a door opening. The jack shaft garage door operator includes a drive unit having an electric motor for driving a jack shaft mounted above a door opening. A pull-up cable drum is connected to the jack shaft and has a multi-strand steel pull-up cable that may be payed out to lower a door or wound up to raise the door. The cable tension sensing apparatus includes a cable guide to retain the cable a substantially fixed distance from the wall and a spring driven cable follower which urges against the cable extending between the drum periphery and the cable guide. An alerting switch is connected to the cable follower and sends a signal indicating loss of cable tension when the cable follower moves beyond a predetermined distance. Additionally, the movement of the cable follower moves a door blocking arrangement to a position to block movement of the door when being raised without use of the motor.