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Discussion Starter · #1 ·
This is a simple question, but maybe a strange one.
Suppose that you have several Accutrons (specifically some mixture of 214s, 218s, & 219s) running at one time. Do you find that, if they are kept close together, in basically the same orientation, & in a situation which readily transmits vibrations ― for instance, dial-downward on a hard table surface ― or at least without any sound-deadening material, that they will keep closer to the same time than if they are separated? I am intrigued by the possibility that the communication of fork vibrations from one movement to another could help to hold the two in lock-step. Some preliminary observations of mine suggest that this may be so, but I only have three running Accutrons (two 219s, & one Citizen 218-equivalent), so I can't really study this topic with any thoroughness.
 

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I don't think it is such a strange question at all. I don't know the answer to give you but it is an interesting proposition.
 

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I think probably not. I've tried connecting two forks together at their base, pointing in opposite directions, hoping they would couple and give reduced positional dependence. There was no coupling apparent even with this direct mechanical connection.

I recall one of the early patents talks about fork shape, and how it was important to shape the fork in a way that minimized coupling motion to the pillar plate (to minimize wasting power). Clearly there is still some coupling, you can see it on the ammeter if you compare holding the movement in a soft hand vs. against a hard surface. And of course you can hear it on your headboard at night in a quiet room! But after my experiment I don't think it can really cause the effect you're wondering about.

Do you know about the chronometer with three 214 movements with forks pointing every 120 degrees? I don't think anyone here has actually determined for sure how they are coupled, but I expect it's electric and not mechanical at all.
 

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Discussion Starter · #4 · (Edited)
Do you know about the chronometer with three 214 movements with forks pointing every 120 degrees? I don't think anyone here has actually determined for sure how they are coupled, but I expect it's electric and not mechanical at all.
Egads! That sounds like a monstrosity, indeed. The ESA balanced tuning fork was definitely the better solution to the problem of positional variation!

If it was anything like the super-accurate pendulum clocks of the middle 20th century, the circuitry would probably have been arranged in a round-robin fashion, with the feedback pulse from one fork triggering the drive coil on the adjacent fork. The effect arrived at is a kind of phase-locked loop, in which the rates of the individual timing elements average out.
 

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I have a Swiss made Navigator MK II S that has three 214 movements and I understand that two are “slaves” to the main “master”movement which is the only one to have the electronics fitted.
I acquired mine from a watchmaker who bought it direct from Bulova UK when he attended a Accutron training course back in the day.
He told me that Bulova recalled these particular marine clocks from dealers due to the development of the Accuquartz based version that was significantly cheaper to produce as only needed one movement to achieve a similar degree of accuracy.

 

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Egads! That sounds like a monstrosity, indeed. The ESA balanced tuning fork was definitely the better solution to the problem of positional variation!

If it was anything like the super-accurate pendulum clocks of the middle 20th century, the circuitry would probably have been arranged in a round-robin fashion, with the feedback pulse from one fork triggering the drive coil on the adjacent fork. The effect arrived at is a kind of phase-locked loop, in which the rates of the individual timing elements average out.
Yes, and remembering that the Esa tuning fork was a development of the Accutron tuning fork principle, not an independent occurrence. Also the Esa fork is quite a bit more fragile than the Accutron forks, and often suffer damage due to heavy shocks. I have a box of forks that are way off frequency due to that. Unfortunately they are not readily re-tunable with inflicting nasty cosmetic damage to them.

Rob
 
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