Winding your watch while its operating

A watch in a way is like a very complicated clockwork toy/wind up toy.



From my understanding, the mainspring when wounded, has a lot of elastic potential energy.



As it unwinds; say in a clockwork toy, that stored up elastic potential energy gets converted into kinetic energy and the toy moves. Once the spring reaches its fully unwound state, the toy stops. Most of the time, this release of energy isn't linear and we would see the toy start off by moving really fast and slow down a little and remain in constant speed before slowing down to a complete stop.



In a watch, this is non ideal and as such, we have terms like isochronism where the release of stored up elastic potential energy into kinetic is pretty consistent. Modern day mechanical watches utilize a mainspring that is shaped in such a way that it evens out the release of energy from fully wound to completely unwound. What they did was to have several tight coils at the beginning of the spring which then tapers to a straight mid section followed by a curved end section that is curved in the opposite direction as the beginning section.



So to sum it up, a watch would have a means of storing energy (the mainspring), a means of transporting that energy (the gears and stuff), a means of measuring the rate of dispense of energy (the dial) and finally a means to regulate the rate at which energy is released (escapement wheel).



This is why a watch can keep running for extended periods of up to a few days as compared to that of a clockwork toy.



That pretty much sums up my understanding of how a basic automatic watch works.



There is however one thing that I'm not quite sure about. In a Clockwork toy, when its running, you can see the winding key spinning. So if you try to wind it up, the toy will stop moving as you wind the key and continue moving when one releases it.



Whereas in a watch, it's always ticking even when you're winding it. How does that work?



I understand how bi-directional winding rotors work by means of an eccentric off center axle and two elongated claw like pawls with a push-pull action but I've never really quite understood how a watch can continue to tell time actually when you're winding it.



Wouldn't the rate of release of the stored up energy be affected when you're winding it?



So yeah, my question is, how is it that the watch can continue to operate, seemingly unaffected while one is winding it?

I not entirely sure but it might be the slipping clutch. It's like when you cycle, when you stop pedaling, the bicycle still moves. Of course I may just be over simplifying it.





Via a mobile device

Hmm, wikipedia has an article about how mainspring works.



Link: http://en.wikipedia.org/wiki/Mainspring



From my understanding, in the older days the inner end of the spring is hooked onto an axle (the pole in the dead center of the mainspring) and the outer end of the spring is hooked up to a stationary pole. When one handwinds the spring, the mainspring stops temporarily.



Modern watches using "going barrel", the outer end of the spring now being hooked up to the mainspring barrel, and the barrel itself is a gear on its own which is free to turn. So when one winds the mainspring the barrel still continues to turn.