Quote:
Originally Posted by Station X
It might be worth looking up the patents mentioned on the label.
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Yes indeed
https://patents.google.com/
us2724233
Device for correcting clocks for errors of more than one hour
us2724232
Clock correcting means of more than one hour range
us2700231
Synchronous motor controlled secondary clock synchronizing device.
The present invention relates to timekeeping apparatus and, more particularly, to secondary clocks and similar timekeeping units of the type normally driven by individual driving motors, as for example, synchronous alternating current motors which are automatically regulated at selected intervals in response to time signals transmitted from a source of correct or standard time. The invention is designed as an improvement over the structure shown and described in Patent 2,569,815 to C. E. Larrabee which was issued on October 2, 1951.
In the patent above referred to the clock mechanism is adapted to be uniformly and continuously driven by means of a synchronous alternating current motor which receives its impulses from the commercial 60-cycle power line. Means are also provided whereby an electrical signal is transmitted to .the secondary clock over the regular power line at a moment which occurs slightly before the fifty-ninth minute of each standard time hour and which terminates at the fifty-ninth minute of the hour, such an impulse serving to initiate a correction cycle whereby,
if the secondary clock is running slow with respect to standard time at the fifty-ninth minute of the hour, it will be brought up to the correct :time during the sixtieth minute of the hour so that when the sixtieth minute is completed and the first minute ,of the next succeeding hour commences, the clock will be accurately synchronized with the standard time source[...]
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