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:
May. 30, 2000
Filed:
Oct. 29, 1998
Thomas G Osborne, Highland Village, TX (US);
Optek Technology, Inc., Carrollton, TX (US);
Abstract
A lock for an automobile ignition system includes a sleeve having a cylindrical inner surface. A lock cylinder is provided which is rotatably mounted within the sleeve and has a cylindrical outer surface defining a cylindrical interface with the inner surface of the sleeve. The cylinder includes a keyway adapted for receiving a key used to rotate the cylinder between an off and start position. A differential magnetic comparator having a pair of magnetically sensitive areas is mounted on the sleeve for detecting when the cylinder is rotated to the start position to generate an ignition signal. A magnet is mounted to the cylinder interface for generating a magnetic flux and for activating the comparator when the cylinder is rotated to the start position. A difference in the magnetic flux density present on the pair of magnetically sensitive areas causes the comparator to generate the ignition signal. However, in the presence of a magnet external to the lock, the magnetically sensitive areas detect no difference in magnetic flux density which prevents the comparator from generating the ignition signal.