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US 3,937,003 AGranted
Electric clock
AssigneeVDO Adolf Schindling AG
InventorsDieter Busch, Roland Sudler
Life of this patent
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Abstract
The invention relates to an electric clock with an oscillator, especially a quartz oscillator, a frequency divider connected thereto, and a control stage connected to the output of the frequency divider either directly or via a pulse shaper stage. Through the control stage, a stepper motor, preferably a single-phase stepper motor, connected to the hand mechanism is acted upon by square-wave pulses of identical or alternating polarity.
Claims8
In an electric clock comprising:
- A. oscillator means (1) for providing a substantially fixed frequency oscillating electrical signal,
- B. frequency-divider means (2) responsive to the fixed frequency oscillating electrical signal for providing a reduced frequency oscillating electrical signal,
- C. a stepper motor (7) for driving hands of the clock, and
- D. control means responsive to the reduced frequency oscillating electrical signal for driving the stepper motor,
- the improvement wherein the control means comprises:
- E. pulse generating means responsive to the reduced frequency signal for generating a train of pulses at said reduced frequency, and
- F. decay-time means (20, 21, 31) for lengthening the decay-time of the trailing edge of each pulse in said train of pulses.
4 more elements
Dependencies are inferred from the claim text.