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Anonymous

"Watch and Clock Escapements A Complete Study in Theory and Practice of the Lever, Cylinder and Chronometer Escapements, Together with a Brief Account of the Origin and Evolution of the Escapement in Horology"

To the writer's mind this is not
just as it should be, and may lead to misunderstanding and bad
construction. We should always bear in mind the fact that the basis of a
locking face is a neutral plane placed at right angles to the line of
thrust, and the "draw" comes from a locking face placed at an angle to
such neutral plane. A careful study of the diagram at Fig. 88 will give
the reader correct ideas. If a tooth locks at the point _c_, the
tangential thrust would be on the line _c h'_, and a neutral locking
face would be on the line _A c_.

NEUTRAL LOCKINGS.
To aid in explanation, let us remove the pallet center to _D_; then the
line of thrust would be _c D_ and a neutral locking face would coincide
with the line _m m_, which is at right angles to the line _c D_. If we
should now make a locking face with a "draw" and at an angle to the line
_c D_, say, for illustration, to correspond to the line _c c'_ (leaving
the pallet center at _D_), we would have a strong draw and also a cruel
engaging friction.


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