David Walter
250
The concept of............
The maintaining spring as invented by John Harrison is to provide equal energy during winding.
When a weight driven or fusee clock does not have a maintaining ratchet the train will reverse during winding thus making a mokery of timekeeping.
The purpose of the maintaing spring is to provide equal energy during winding which will take aproximatly 20 seconds, however once the maintaing ratchet is engaged the spring will typically have enough energy to drive the clock for about 10 minutes.
If the spring is too weak the train will reverse during winding and the time shown will now be wrong.
If the spring is too strong it will exert more pressure (energy) at the escapement giving the pallets a stronger impulse and thus increasing the arc of the pendulum. An increase in the pendulum arc (at any time) will cause a loosing rate as well interfere with the stability of the pendulum which may well take hours to re-stabilize and the time indicated will be wrong.
It is clear that the maintaining spring must be matched to the mass of the driving weight to maintain precision timekeeping, the actual act of winding is in itself enough unavoidable interference to a high precision clock.
David
A David Walter Double Pendulum Clock – Part 2, Making the Barrel
This is good stuff...Thanks David, Thanks Don.
Wonderful to see how the parts are ...
Torque = Force x Radius?
The concept of............
Matched pair of springs
