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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 by Anonymous
page 22 of 243 (09%)
the lever escapement in that notable concern.

If a horological student should construct a large model on the lines
laid down in Mr. Grossmann's work, the entrance pallet would be faulty
in form and would not properly perform its functions. Why? perhaps says
our reader. In reply let us analyze the action of the tooth _B_ as it
rests on the pallet _A_. Now, if we move this pallet through an angular
motion of one and one-half degrees on the center _g_ (which also
represents the center of the pallet staff), the tooth _B_ is disengaged
from the locking face and commences to slide along the impulse face of
the pallet and "drops," that is, falls from the pallet, when the inner
angle of the pallet is reached.

[Illustration: Fig. 16]

This inner angle, as located by Mr. Grossmann, is at the intersection of
the short arc _i_ with the line _g n_, which limits the ten-degree
angular motion of the pallets. If we carefully study the drawing, we
will see the pallet has only to move through eight degrees of angular
motion of the pallet staff for the tooth to escape, _because the tooth
certainly must be disengaged when the inner angle of the pallet reaches
the peripheral line a_. The true way to locate the position of the inner
angle of the pallet, is to measure down on the arc _i_ ten degrees from
its intersection with the peripheral line _a_ and locate a point to
which a line is drawn from the intersection of the line _g m_ with the
radial line _a c_, thus defining the inner angle of the entrance pallet.
We will name this point the point _x_.

It may not be amiss to say the arc _i_ is swept from the center _g_
through the point _u_, said point being located ten degrees from the
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