[time-nuts] 1903 Self-setting / self-winding clock
brooke at pacific.net
Sat Nov 1 17:46:40 EDT 2014
There's a heart shaped cam that forces the hour, minute and if the clock has one the second hand to 12:00 and holds them
there until the sync pulse goes away.
Note the second hand only was used on clocks in radio stations so they could join the network. For that 1 second was
Mike Baker wrote:
> This particular 1903 Railroad self-setting/winding
> pendulum regulated clock needed only an hourly
> signal from a Western Union telegraph line to
> provide momentary closure of a relay contact.
> This supplied +3 VDC to rewind the spring and also
> reset the sweep seconds hand on the hour, every hour.
> From what I have learned about this, the resetting of
> the sweep seconds hand is mechanically coordinated
> to occur when the pendulum is at either end of its
> swing. It appears that is no way (that I know of) to
> guarantee that the "telegraphed" reset pulse would
> coincide with either end of the pendulum's travel.
> Apparently, the resetting of the sweep seconds hand
> will only occur within the time frame of any single
> pendulum swing. I suppose this means that the clock
> might be in error by as much as nearly one swing of
> the pendulum because it has to reach the end of its
> swing before the second hand is reset.
> Just guessing here, but I am thinking that all this
> clock needs is a 1-second long closure of a relay
> contact on the hour, every hour. I don't think
> that leap-seconds are an issue here as the clock
> can be manually adjusted for that whenever a leap
> second occurs. So-- it comes back to counting
> 3600 one-second pulses from a GPS clock...? Or
> am I missing something here...?
> Mike Baker
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