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. 01, 1993
Filed:
Jan. 03, 1992
George C Wright, Duvall, WA (US);
Intermec Corporation, Lynnwood, WA (US);
Abstract
A circuit for detecting the motion of an oscillating motor driving a mirror for causing a light beam to scan. The circuit is included in a laser scanner for illuminating and reading bar codes, and detects the presence of conditions which prevent the motor from moving, such as a broken wire in a winding. The motor has two windings which are driven by a logic device to cause the motor to oscillate between two extreme angular positions. Each winding has two legs. The voltage on at least one of the legs is monitored when the leg is not being driven by the logic device, to detect the presence of an electromotive force voltage produced by motion of the motor. The monitored voltage is conditioned and transmitted to the logic device. In one embodiment, the monitored voltage is sampled twice and the two samples compared to provide an indication whether the motor is moving.