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:
Apr. 24, 2007
Filed:
Mar. 18, 2005
Robert Urman, Schaumburg, IL (US);
James W. Citta, Lombard, IL (US);
Robert Urman, Schaumburg, IL (US);
James W. Citta, Lombard, IL (US);
Wabtec Holding Corp., Wilmerding, PA (US);
Abstract
A capacitance based switch device employs an electric field imaging device electrically coupled via an electrical conductor to a conductive electrode member that is attached to the door or any other suitable surface. Such electric field imaging device generates a sine wave which is transmitted to the conductive electrode member and produces a surrounding electrical field. Any human body part which enters such electrical field will create a capacitance load due to the body being grounded to a surface. Reduction in distance between the body part and the conductive electrode will increase the capacitance and will decrease the voltage intermediate the resistor and conductive electrode which is an inverse function of the capacitance. Such change in voltage will be detected by a microcontroller by comparing voltages at each end of the resistor and the change exceeding a predetermined threshold will be associated with an output control signal.