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:
Mar. 27, 1990
Filed:
Sep. 29, 1988
Bruce Kamens, Thomaston, CT (US);
Timex Corporation, Waterbury, CT (US);
Abstract
An improved drive circuit for a quartz analog wristwatch having a bipole stepping motor with a drive coil, a power supply, a gear train having a plurality of gears driven by the rotor, a plurality of output members with hands rotatably driven by said gears, the rotor, gears, output members and hands together comprising a rotating system, wherein the improvement comprises a low impedance drive coil, first circuit means arrange to generate periodic pulses of alternating polarity at a normal timekeeping frequency, second circuit means arranged to supply successive drive pulses of alternating polarity to the coil at an intermediate frequency on the order of 300 to 600 pulses per second selected to sustain and synchronize the rotating system at a substantially constant angular velocity, and third circuit means arranged to modulate the periodic pulses generated by the first circuit means so as to chop them at a high frequency on the order of 4 kilohertz at a 25 to 50 percent duty cycle selected with regard to the low impedance coil, so that energy which would otherwise be consumed by the coil is reduced during normal timekeeping. A braking pulse of 22 to 30 milliseconds in duration is applied to stop the high speed rotating system at the conclusion of time setting.