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:
Jun. 14, 1977
Filed:
Oct. 06, 1975
Gerald W Mills, Ramsey, NJ (US);
Other;
Abstract
A safety system for automatically operated sliding panel doors, specifically elevator doors, having acoustic wave transmitters and receivers arranged in a row along the moving door's leading edge. Short bursts of acoustic energy are projected both in front of the door and to one or both sides so as to 'sweep' a three-dimensional space, in and near the door's path, representing a zone of potential danger to persons or objects therein. Reflected energy from persons or objects in the danger zone is usable if it is received, following each transmitted burst, during a prescribed time interval representing combinations of the doorway opening distance and other selected parameters, and usable reflections are converted to a control signal to stop and re-open the doors before they strike the endangered person or object.