We are
aware this condition is, in a degree, necessary from the use of exposed
pallets. In many of the English lever watches with ratchet teeth, the
locking faces are made cylindrical, but with such watches the pallet
stones, as far as the writer has seen, are set "close"; that is, with
steel pallet arms extending above and below the stone.
There is another feature of the club-tooth lever escapement that next
demands our attention which we have never seen discussed. We refer to
arranging and disposing of the impulse of the escape wheel to meet the
resistance of the hairspring. Let us imagine the dotted line _A d_, Fig.
89, to represent the center of action of the fork. We can readily see
that the fork in a state of rest would stand half way between the two
banks from the action of the hairspring, and in the pallet action the
force of the escape wheel, one tooth of which rests on the impulse face
of a pallet, would be exerted against the elastic force of the
hairspring. If the force of the mainspring, as represented by the
escape-wheel tooth, is superior to the power of the hairspring, the
watch starts itself.
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