Improved Anchor for Lever Escapement in Time Pieces.
Year: 1893

page_text: Date of Application, 22nd Sept., 1893-Accepted, 28th Oct., 1893
COMPLETE SPECIFICATION.
Improved Anchor for Lever Escapement in Time Pieces.
1, JOHN HENRY LANGHORST, of Jackson, County of Amador, State of
California, U.S.A., Mechanical Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
My invention relates to the class of time pieces, and particularly to the class
of anchors for detached lever escapements for watches, clocks and time pieces
generally.
My invention consists in the novel construction of the acting faces of the receiving
and leaving pallets of the anchor, as I shall hereinafter fully describe and
specifically claim.
The object of my invention will hereinafter fully appear.
Referring to the accompanying drawings for a more complete explanation of my
invention,
Figure 1 is a side elevation of a lever escapement in which the escape wheel is
of the type known as "ratchet wheel."
Figure 2 is a side elevation in which the escape wheel is of the type known as
"club wheel."
In both figures my improved anchor is shown.
A is the anchor having a receiving or entering pallet E and a leaving pallet L.
These pallets may be formed integral with the anchor, as shown in Figure 1, or
may be separate pieces inserted therein, as shown in Figure 2, both of which
constructions are usual.
The acting face of the receiving or entering pallet is represented by the a b, and
it will be seen that this is a convex curve.
The acting face of the leaving pallet L is represented by c d and this, it will be
seen, is a straight line.
C is the escape wheel. It can be demonstrated that the allied impulse and
resistance in anchor motion caused by the hair spring power is not equal on the
entering and leaving pallet.
The impulse of the hair spring acts during the first half of each impulse, and is
greatest at the entering points a, e, and is least at the middle of the acting faces of
the pallets.
The resistance of the hair spring acts during the latter half of each impulse,
being greatest at the leaving points b, d, and least at the middle of each
pallet.
It can also be demonstrated that the force of momentum of the running power,
transmitted by the escape wheel to the anchor pallets, is greatest at the point a
of the entering pallet, and the point d of the leaving pallet, and is least at the
point 6 of the entering pallet, and the point c of the leaving pallet, and this is on
account of the different length of radii; that is the outer aud inner radius of
anchor pallet from centre.
It follows that at the point a on the entering pallet E, the greatest momentum
of the running power is allied with the largest hair spring power, and that at the
point b, the smallest momentum of force is allied to the larger hair spring resistance,
which causes an unfavorable, uneven impulse.
On the other hand, on the leaving pallet at e, the smaller momentum of force of
the running power is allied with the larger hair spring power, and at d the larger
momentum of force of the running power is allied with the larger resistance of the
hair spring power which causes a favorable and even impulse. I, therefore,
change the incline of the pallet face on the entering pallet E to a convex

page_text: curve, as shown, which permits more anchor motion during the first half of the
impulse, and allows less anchor motion during the latter half of the impulse.
The impulse power lost at the first half of the impulse is gained at the latter
half, thereby approximately equalizing the impulse on the entering pallet E and on
the leaving pallet L.
The construction which I have herein shown permits another advantage when the
club wheel, as shown in Figure 2, is used; that is the incline on the wheel tooth
can be given the proper proportion, without the faces of the wheel teeth being
chafed or gouged by the entering pallet corner at a.
On the leaving pallet corner at the wheel teeth have ample clearance. I, there-
fore, bring the convex pallet face a-b approximately to the same condition as the
straight pallet face e-d of the leaving pallet, with respect to the angle of incline
of pallet face with its respective tangents of the wheel circle.
This improved construction of the anchor, when used with the ratchet wheel,
permits no less transmission of impulse than any other, and has less resistance of
force when in motion. It is, therefore, less liable to stoppage.
With the club wheel, it has the same advantage, and transmits decidedly more
impulse.
The particular anchor for either wheel can be accurately calculated.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is-
An anchor for a lever escapement for time pieces in which the acting line
for impulse on the lifting face of the receiving or entering pallet is a convex
curve, and the acting line for impulse on the leaving pallet is a straight line,
whereby the lifting power transmitted by the escape wheel is approximately the
same on the entering or receiving pallet and on the leaving pallet, substantially as
herein described.
Dated this 21st day of September 1893.
GEORGE BARKER,
77, Colmore Row, Birmingham, Agent for Applicant.