IMPROVE- MENTS IN LEVER ESCAPEMENTS FOR WATCHES AND OTHER TIMEKEEPERS
Year: 1870

page_text: LETTERS PATENT to Adolphe Nicole, of Soho Square, in the County
of Middlesex, Watch Manufacturer, for the Invention of "IMPROVE-
MENTS IN LEVER ESCAPEMENTS FOR WATCHES AND OTHER TIMEKEEPERS."
Scaled the 15th September 1870, and dated the 28th March 1870.
PROVISIONAL SPECIFICATION left by the said Adolphe Nicole at the
Office of the Commissioners of Patents, with his Petition, on the
28th March 1870.
I, ADOLPHE NICOLE, of Soho Square, in the County of Middlesex,
Watch Manufacturer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN LEVER ESCAPEMENTS FOR WATCHES AND OTHER TIME-
KEEPERS," to be as follows:-
It is well known by those skilled in the manufacture of watches that
the ordinary lever escapement though so generally used has certain
inherent defects which impair the durability of the mechanism and the
accuracy of the watch. The chief of these objectionable features arises
from the necessity of "banking." The method of banking most com-
monly used is that in which two pins are placed at the sides of the lever

page_text: in the proper position to limit the oscillations thereof to the desired
distance in both directions. But this means of equalizing the motion of
the lever though generally adopted is objectionable for the following
reasons: A sudden or violent disturbance of the watch such as
frequently occurs in carrying or winding up the same will have the
effect of causing the balance wheel to turn or swing far beyond its
proper regular distance, and as a consequence of this exessive motion
the impulse pin strikes the outside of the lever fork and throws the
lever against one of the banking pins with sufficient force in some cases
to injure the pivots or journals of the lever or balance wheel, causing
also a sensible acceleration of speed and a proportionate error in the
time. These pins moreover are very easily bent or broken in cleaning
the watch, as they are of necessity made of small diameter, so that they
may not be perfectly rigid but may be sufficiently elastic to reduce to
some extent the ill effects of the concussion to which the lever is
subjected at each oscillation.
To obviate the above and other disadvantages connected with the
ordinary detached lever escapement I construct the teeth of my improved
escape wheel of such a form as to effect by the wheel itself the object
desired to be obtained by the banking, and thereby obviate the
necessity for the banking pins or other like means for limiting the
motion of the lever and pallet within the proper distance. I also am
enabled to dispense with the safety action, as with my improved form of
escape wheel if the pallet should be caused by any accidental disturbance
to leave its position of rest while the impulse pin is out of the fork it
will not cause a stoppage of the mechanism or injure the pivots, or
journals, or other portions of the mechanism.
I make my improved escape wheel with a notch or V-shaped recess at
the outer extremity of each tooth; one side of this recess forms the
locking surface, while the other side limits the motion of the pallet when
the same is working regularly. From the bottom of the locking surface
the tooth is curved or bevelled forward towards the ring of the wheel so
as to present a surface which if the pallet passes down beyond the
locking surface will act upon it in such a manner as to cause a recoil
thereof, and so without any blow or concussion return the lever to its
proper position. The lever has no horns but a simple notch, the
extremity of the lever outside the said notch being bevelled or inclined
backward, and when the impulse pin strikes the outside of this lever it

page_text: slides over the bevelled or inclined surface, and enters the notch, and
the working is uninterrupted.
I am aware that it has already been proposed to construct the escape
wheel with teeth of such a form as will produce this recoil or lifting
action upon the pallet, but no efficient escapement has yet been con-
structed upon this principle. In all cases where two surfaces work
together or in contact with cach other it is very important to prevent
the accumulation of coagulated or thick oil or other matter, which
would cause adhesion between the working parts, and a consequent
inequality of action, and this object I accomplish by forming my
improved teeth with the aforesaid recess or notch, so that no oil or dirt
can lodge on the locking surface, and consequently the unlocking is
always performed with the same regular amount of force. It is also
essential to the correct action of a lever escapement that the lever
should vibrate to equal distance on each side of the centre line of its
motion, and that the lifting action should be equal on cach pallet arm.
The inner side of the notch or recess of the teeth forms a shoulder or
projection, which in the regular working of the mechanism stops the
pallet at each locking. The second pallet arm or that nearest the
balance wheel is shorter than the first arm, but has its lifting surface so
inclined as to compensate for the difference of length; this different
inclination also prevents its entering the notch of the tooth so deeply in
locking as the first arm. Thus it will be seen that the length, radial
distance, and angle of the lifting surfaces are so proportioned that the
oscillations of the lever are equal, and an equal lifting force is exerted
on both arms.
The arbors or spindles of the escapement mechanism have herc-before
been made parallel or cylinderical down to the plate, where they have
a shoulder, below which is the pivot or journal of greatly reduced
diameter; consequently they are rigid and liable to break when
subjected to any sudden strain such as frequently occurs from the above
mentioned causes. To avoid this difficulty I make the arbors for my
improved mechanism taper or conical with a gradual inclination from
about the middle of the arbor to the end of the pivot or step, and by this
means still further increase the durability of my improved mechanism.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Adolphe Nicole in the Great Seal Patent Office
on the 27th September 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ADOLPHE
NICOLE, of Soho Square, in the County of Middlesex, Watch Manu-
facturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of March, in the
year of our Lord One thousand eight hundred and seventy, in the thirty-
third year of Ier reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Adolphe Nicole, Her special licence that
I, the said Adolphe Nicole, my executors, administrators, and assigns,
or such others as I, the said Adolphe Nicole, my executors, adminis-
trators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN LEVER
ESCAPEMENTS FOR WATCHES AND OTHER TIMEKEEPERS," upon the condition
(amongst others) that I, the said Adolphe Nicole, my executors or
administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Scal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Adolphe Nicole, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawing
forming a part of this Specification :-
It is well known by those skilled in the manufacture of watches that
the ordinary lever escapement, though so generally used, has certain
inherent defects which impair the durability of the mechanism and the
accuracy of the watch. The chief of these objectionable features arises
from the necessity of banking. The method of banking most com-

page_text: monly used is that in which two pins are placed at the sides of the lever
in the proper position to limit the oscillations thereof to the desired
distance in both directions. But this method of equalizing the motions
of the lever, though generally adopted, is objectionable for the following
reasons: A sudden or violent disturbance of the watch, such as fre-
quently arises in carrying or winding-up the same, will have the effect
of causing the balance wheel to turn or swing far beyond its proper
regular distance, and as a consequence of this excess of motion the
impulse pin strikes the outside of the lever fork, and throws the lever
against one of the banking pins with sufficient force in some cases to
injure the pivots or journals of the lever or balance wheel, causing also
a sensible acceleration of speed and a proportionate error in the time.
These pins, morcover, are very casily bent or broken in cleaning the
watch, as they are of necessity made of small diameter, so that they may
not be perfectly rigid but may be sufficiently clastic to reduce to some
extent the ill effects of the concussion to which the lever is subjected at
cach oscillation.
To obviate the above and other disadvantages connected with the
ordinary detached lever escapement I construct the teeth of my improved
escape wheel in the form shewn in the Drawing, so as to effect by the
wheel itself the object desired to be obtained by the banking, and thereby
obviate the necessity for the banking pins or other like means for
limiting the motion of the lever and pallet within the proper distance.
I also am enabled to dispense with the safety action, as with my im-
proved form of escape wheel if the pallet should be caused by any
accidental disturbance to leave its position of rest while the impulse pin
is out of the fork it will not cause a stoppage of the mechanism or
injure the pivots or journals or other portions of the mechanism. If
desired, however, I may provide my improved escapement mechanism
with the ordinary safety action.
Figure 1 is a plan or top view of my improved escapement mechanism;
Figure 2 is an elevation of a detached portion of the same.
I make my improved escape wheel a with a notch or recess at the
outer extremity of each tooth c. One side 1 of this recess forms thic
locking surface, while the point 2 limits the motion of the pallet & when

page_text: "
the same is working regularly. From the point 2 the locking surface
of the tooth is curved or bevelled towards the ring e of the wheel, so as
to present a surface, which if the pallet passes down beyond the locking
surface 2 will act upon it in such a manner as to cause a recoil thereof,
and so without any blow or concussion return the leverf to its proper
position. The lever ƒ has no horns but a simple notch g, the extremity
of the lever outside the said notch being bevilled or inclined backward,
and when the impulse pin strikes the outside of this lever it slides over
the bevelled or inclined surface 3 and enters the notch g, so that the
working of the watch continues without interruption.
I am aware that it has already been proposed to construct the escape
wheel with teeth of such a form as will produce this recoil or lifting
action upon the pallet, but no efficient escapement has yet been con-
structed upon this principle, partly because of the accumulation of thick
oil on the tooth. In all cases where two surfaces work together or in
contact with each other it is very important to prevent the accumulation
of coagulated or thick oil or other matter which would cause adhesion
between the working parts and a consequent inequality of action; and
this object I accomplish by forming the aforesaid recess or notch b so
that no oil or dirt can lodge on the surfaces which come in contact with
the pallet, but if there should be any accumulation it will be entirely at
the bottom 4 of the recess, consequently the unlocking is always effected
with the same regular amount of force, and no stoppage will occur from
the failure in the action of this part of the mechanism. It is moreover
essential to the correct action of a lever escapement that the lever should
vibrate to equal distances on each side of the centre line of its motion,
and therefore the arms of the pallet must be so formed and arranged in
relation to the teeth of the escape wheel as to limit the vibration of the
arm to the proper distance. In my improved wheel the shoulder or
projection 2 in the regular working of the mechanism stops the pallet in
such a position as to equalize the motion of the lever fon cach side of
the line x, x. The central points 5 of the two pallet arms are at equal
distances from the centre 6 on which the lever foscillates. The point 7
of both of the arms h and i which comes in contact with the point 2 of
the wheel is one-third of the entire length of the surface 8, 9, from the
point 8, and the length, radial distance, and angle of the lifting surfaces
are so proportioned that the oscillations of the lever fare equal, and an
equal lifting force is exerted on both arms.

page_text: The balance staff or arbor of the escapement mechanism have here.
tofore been made parallel or cylindrical to the plates, where they have a
shoulder, beyond which are the pivots or journals of greatly reduced
diameter, consequently it is rigid and liable to break when subjected to
any sudden strain, such as frequently arises from the above-mentioned
causes. To avoid this difficulty I make the balance staff ; for my
improved mechanism taper or conical, with a gradual inclination from
a point as near the middle of the staff as practicable to the end, and by
this means render it elastic, and still farther increase the durability of
my improved mechanism.
Having thus fully described my said Invention I wish it understood
that I claim,
First. The escape wheel with the teeth formed as shewn operating in
combination with a pallet, both arms of which have an equal action, and
with an equally oscillating lever, which may have a simple notch and
bevelled surfaces to conduct the impulse pin into the said notch, as
shown, or may have the ordinary safety action, the construction and
operation of all of these parts being substantially as herein set forth for
the purposes specified.
Second. Making the balance staff of a lever escapement taper from
the central portion to the point for the purposes set forth.
In witness whereof, I, the said Adolphe Nicole, have hereunto set
my hand and seal, this Twenty-seventh day of September, in the
year of our Lord One thousand eight hundred and seventy.
Witness,
WM. ROBT. LAKE.
A. NICOLE. (L.S.)