IMPROVEMENTS IN LEVER ESCAPEMENTS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by the said James Rattray at the Office
of the Commissioners of Patents on the 22nd September 1880.
JAMES RATTRAY, of Dundee, in the County of Forfar. "IMPROVEMENTS IN
LEVER ESCAPEMENTS."
My Invention of improvements in lever escapements consists mainly of a single
arm or lever with an impulse pin or "pallet" and two escape wheels arranged in
the following manner :-
The lever is mounted on an axle or "staff" in the usual way; the impulse pin, a
ruby of a triangular form is fixed in the arm on either side of the axle, at pleasure;
the two escape wheels are placed one on each side of the arm, and having the
impulse pin between them, and as nearly as possible in the line of centres. The
wheels act on the impulse pin alternately, it vibrating between them. The motion
is given off in the usual manner by the lever. This escapement is equally applicable
to watches and clocks.
For this lever escapement the following advantages are claimed-Simplicity of
construction, ensuring mathematically correct manipulation in making, so that the
two wheels act with equal power, thereby giving equal impulse to the balance or
pendulum.
By reason of the direction given to the wheels the impulse increases in power as
the tooth passes along the impulse pin, a peculiar property of much importance, as
all watchmakers will admit. There are no difficult points, and liability to
derangement is avoided or minimised. It will make both a better time keeper
and a cheaper watch than heretofore. For a working man's watch or a railway
guard's time keeper it will be of the greatest service.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Rattray in the Great Seal Patent Office on the 22nd March
1881.
James Rattray, of Dundee, in the County of Forfar. “IMPROVEMENTS IN
LEVER ESCAPEMENTS."
My Invention of improvements in lever escapements consists of a single arm or
lever with an impulse pin or pallet and two escape wheels arranged in the
following manner:-The lever.is mounted on an axle or staff in the usual way;
the impulse pin, a ruby of a triangular form, is fixed in the arm on either side of
the axle, at pleasure; the two escape wheels are placed one on each side of the arm,
and having the impulse pin between them, and as nearly as possible in the line of
centres. The wheels act on the impulse pin alternately, it vibrating between them.
The motion is given off in the usual manner by the lever. This escapement is
equally applicable to watches and clocks. For this lever escapement the following
advantages are claimed:-Simplicity of construction, ensuring mathematically
correct manipulation in making, so that the two wheels act with equal power,
thereby giving-equal-impulse-to-the-balance-or-pendulum.--By-reason-of-the
direction given to the wheels the impulse increases in power as the tooth passes
along the impulse pin, a peculiar property of much importance, which will doubtless
-be-recognised by watchmakers. There are no difficult points, and liability to
_derangement-is-avoided-or-minimized-It-will-make-both-a-better-time-keeper-
and a cheaper watch than heretofore. For a working man's watch or a railway
guard's time keeper it will be of the greatest service.
Having thus far described the nature of the said Invention I will now proceed,
by reference to the accompanying Drawings, to further describe in what manner
the same is to be performed or carried out in practice.