Gramaisc
Forum O. G.
Today, I finally got around to looking at an old battery clock that's been waiting for a while. It takes a D-cell and I was expecting it to be one of the usual early magnetic impulse things, giving a nudge to a balance wheel, as in a normal clockwork clock - but, it's not.
It's not immediately apparent in the still photograph, but it is running happily there, a good minute or two after the battery was removed...
I had noticed a whirring sound when I cleaned thing up and inserted the battery - what actually happens is that the clock is a fairly normal spring-driven mechanism, but the spring is topped up every few minutes by a small motor, driven by the battery.
I've never seen such a thing before.
Unfortunately, I can't see any identifying marks anywhere.
Edit - three minutes between each wind - the spring tension is monitored via a leaf-spring that connects the motor when the tension drops.
It's not immediately apparent in the still photograph, but it is running happily there, a good minute or two after the battery was removed...
I had noticed a whirring sound when I cleaned thing up and inserted the battery - what actually happens is that the clock is a fairly normal spring-driven mechanism, but the spring is topped up every few minutes by a small motor, driven by the battery.
I've never seen such a thing before.
Unfortunately, I can't see any identifying marks anywhere.
Edit - three minutes between each wind - the spring tension is monitored via a leaf-spring that connects the motor when the tension drops.
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