The entire power of such an escape wheel is devoted to giving
impulse to the balance.
The extent of angular motion of the balance during such impulse is, as
previously stated, termed the "lifting angle." This "lifting angle" is
by horological writers again divided into real and apparent lifts. This
last division is only an imaginary one, as the real lift is the one to
be studied and expresses the arc through which the impulse face of the
tooth impels the balance during the act of escaping, and so, as we shall
subsequently show, should no more be counted than in the detached lever
escapement, where a precisely similar condition exists, but is never
considered or discussed.
We shall for the present take no note of this lifting angle, but confine
ourselves to the problem just named, of so arranging and designing our
escape-wheel teeth and cylinder that each half of the tooth space shall
give equal impulses to the balance with the minimum of drop. To do this
we will make a careful drawing of an escape-wheel tooth and cylinder on
an enlarged scale; our method of making such drawings will be on a new
and original system, which is very simple yet complete.
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