The Craftmans Shop > General Crafts
Clocks & Pocket Watches
Darren:
Ah, so you mean it's the time between swinging from left to right that regulates time.
How is that controlled to alter the rate, thus accuracy?
raynerd:
--- Quote from: Darren on November 06, 2009, 07:49:39 AM ---Thanks Chris,
I suppose it's the energy of the falling weight that keeps the pendulums momentum from coming to a halt.
But what regulates each release of movement (time wise) :scratch:
--- End quote ---
The escape wheel teeth are cut cleverly to give the pendulum a little "push" as it releases the wheel! It is really clever, if it didn`t, friction would eventually grind it to a halt. As the pallet disengages with the escape wheel, the "power" or drive from the motion train gives the pallet a little push which in turn keeps the pendulm moving.
--- Quote ---What regulates the movement
--- End quote ---
- as the pendulum goes to one side, the pallet releases a tooth and moves around a little, the pendulum swings back and engages the pallet back and stops the escape wheel. And so it continues. The rate at which the pendulum swings dictates the release of the escape wheel and timing of the clock. Since the equation for the period of pendulum only really involve length and not mass, the wheel ratio is based on the length of the pendulum as this is going to ultimately dictate the release of the escape wheel and hence the time.
Chris
raynerd:
--- Quote from: Darren on November 06, 2009, 07:51:35 AM ---Ah, so you mean it's the time between swinging from left to right that regulates time.
How is that controlled to alter the rate, thus accuracy?
--- End quote ---
There are few ways of regulating the clock but really it is due to the length of the pendulum. And we are talking about small amounts. The pendulum can be moved slightly up and down on the clock to change the period and therefore the time. Thats is why before I said that you need to take into account the gear ration when selecting the pendulum length or vice versa! Say you want gear ratio X for your mantle clock but that requires a 1m long pendulum, it is no use but in a longcase clock it would be fine for the gear train! The gear ratio needs to be selected to suit to pendulum length OR you can add to the motion train to gear the ratio down to suit. But this adds more wheels, more friction etc etc.
There are tables which say the ideals or suggestions and many clock use similar motion trains and ratios.
Chris
Darren:
So to adjust the speed you adjust the length of the pendulum?
raynerd:
yes, because the pendulum is attached to the pallets, the pallet regulates how fast the escape wheel turns and in turn these dictates how fast the wheels turn and consequently how fast the hands turn since the wheels are ultimately attached to these!
Pretty clever stuff!
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