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:
Dec. 29, 1992
Filed:
Jan. 18, 1990
James McKeefery, Milpitas, CA (US);
James Sachs, Menlo Park, CA (US);
Richard Wotiz, Cupertino, CA (US);
Other;
Abstract
In accordance with the method, first and second substantially parallel conductors are placed along a pathway and coupled to a controller in a manner so that each may carry a current independently controllable by the controller. A sensing coil is placed in a vehicle having a coil axis approximately perpendicular to the plane of the conductors so as to sense the varying magnetic field caused by varying currents through the two conductors. The controller repetitively provides a half-cycle of current of a given frequency in one of the two wires, immediately followed by another half-cycle of current of the opposite polarity or direction in the other of the two wires. The sensing coil on the vehicle senses the magnetic field caused by these varying currents in a manner dependent upon its proximity to each of the two wires, and controls the vehicle steering responsive thereto, sensing a substantially balanced wave when centered between the two wires, a positively distorted wave when closed to one of the wires and a negatively distorted wave when closer to the other of the two wires. Modulation of the frequency of the current in the two wires provides communication capability from the controller to the vehicle for remote steering and speed control. Apparatus for carrying out the method and alternative embodiments are disclosed.