Comments:
Variable-speed hands
I was thinking about the Japanese-style timekeeping over on the AHCI forum: http://ahci.watchprosite.com/show-forumpost/fi-16/pi-5569348/ti-824593/s-0/
He's implementing the variable-length hours in the obvious way, with a 24-hour face and hour indicator blocks that move around to synchronize with the seasonal hour length, since a day is always 24 hours. I was wondering how hard it would be to have a more normal 12 hour face, with fixed indexes and hands that moved at variable speed. So in the dead of winter the hands move really quickly from sunrise-to-sunset, and then much slower at night.
Such a watch would require 2 major complications, sunrise/sunset calculations AND the variable hand speed. I know we can do the first one, but I don't know about the variable speed. The naive way to do it, at least to my mind would be essentially to have a stack of horizontally-coupled chronograph trains, each with slightly different gearing and a cam set that engaged and disengaged them as needed, maybe only 12, an average speed for each month. You'd have to cheat some so that the 12 were in 6 pairs of matched speeds to get the day and night to align. There has to be a better way, but I can't figure out how to jam a CVT into a watch....
A
In love with your idea!
without having the faintest clue, except for the cam, of how to realize it technically.
That could bring me into the habit of wearing two watches per day (or night) one on either wrist for the normal and one for traditional Japanese timekeeping.
The monks in their cells must have been awakened at, for most of us, a very early hour for chanting and meditating - before starting their daily work routine and practise. With a variable time indicator that would place them within the natural cycle of (sun) time and seasons where light and dark flow from one into the other. Perhaps for us too!
As a wrist watch, I would surely welcome it.
Just don't make it overly complicated!
Cheers,
amerix
A very interesting idea...
... in the 18th to early 19th century, there was a "Clock Man" in the Castle and he changed the placement of the weight (distance from the center) on the balance wheel in the clock so that the speed of the hand changed. So, there may be an answer in the "variable inertia moment" so that the the vibration/ beat changes everyday..... Interesting!
Ken
Ken
Still thinking.......
As you said, how to stick a CVT in a watch (and change the ratio twice a day) .
Everything I have thought of up 'til now would just take too much power.
So I keep thinking...............................................
Makes an interesting way to keep the gray cells from going belly up during meetings at work.
Don
Everything I have thought of up 'til now would just take too much power.
So I keep thinking...............................................
Makes an interesting way to keep the gray cells from going belly up during meetings at work.
Don
I was thinking last night..
and think that if we have an hour-only watch with a jumping hour, there's a way to do it. Build a stack of 3 cams, a usual jump-hour snail (rotating once per hour), a 12 hour wheel, jumps one position to increment the hour and a 1 year wheel which indicates the "length" of an hour in the current timeframe, higher for longer hours. every day/night change, the 1 year wheel rotates 180.5 degrees, from the "short" side to the "long" side, and a tiny bit of increment.
The jumping works such that when the height of the usual snail matches the height of the 1 year wheel, the hour jumps ahead (1 step of the 12 hour wheel) and and snail resets to the beginning.
I think all of that works, I'd draw it, but my 3d-rendering is worse then my textual description!
A
The jumping works such that when the height of the usual snail matches the height of the 1 year wheel, the hour jumps ahead (1 step of the 12 hour wheel) and and snail resets to the beginning.
I think all of that works, I'd draw it, but my 3d-rendering is worse then my textual description!
A
Perhaps we could complicate this a bit more?
Can I restate the problem to see if I understand it?
Your challenge is this - build a time keeping device where the 12 Hours (or 720 minutes or 8640 seconds) at night are longer or shorter than the 12 hours (etc) in the daytime. The time variation is determined by the seasons. Right?
If you have a fixed location or a country with smallish latitudinal (vertical) dimension like Japan (roughly 30° to 45°) I can see how you could calculate (or estimate) average changes, but if the country is like the US, with a range from 18° (Hawaii) to 71° (Alaska), the day/night length changes are unreasonable to calculate. You have too much variation, I think.
Of course if you are on the equator, seasonal change is minimal. Only a few minutes day/night variation across a year.
Maybe that fancy "Key of Time" Hublot watch with the faster-slower buttons could provide us some clues?
PS - Variable speed mechanisms might resolve the problem experienced on a ship, when you travel through time zones - say New York to London or vice versa. Since the day is effectively slower or faster by about one time zone per 24 hours of sailing, and the direction of time variation is dependent on sailing speed and direction, this is just a faster change than the seasons, but conceptually it's a similar challenge.
(I believe the precedent is for the captain to designate "shipboard time" and tell passengers the correct time each day, or to designate when the ship goes through time zones.)
Basically...
Though I was assuming this would be tied to a specific longitude and latitude, since it would have to know the time of sunrise and sunset to work at all.
A
A