Improvements in Escapements for Lever Watches and other Timekeepers.
Year: 1888

page_text: Date of Application, 24th Sept., 1888
Complete Specification Left, 24th July, 1889-Accepted, 24th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in Escapements for Lever Watches and other
Timekeepers.
I, RICHARD WHITTAKER of 40 and 41 Kirby Street, Hatton Garden, in the City of
London, Watchmaker, do hereby declare the nature of this invention to he as
follows:-
The object of my invention is to overcome the defects which are known by watch-
makers as the banking errors which take place when the wearer gives sudden move-
ments, and especially when the watch receives a slight rotary motion that is in the
plane of the balance. It is also produced in a going barrel watch by pressing the key
or pendant winding button after the watch is fully wound up. These and like causes
of disturbance make the balance to swing round till the impulse pin strikes the outside
of the lever. If this banking is slight it will cause the watch to gain on its rate; or
if violent it will break the balance staff pivots or ruby pin, or otherwise injure the
escapement.
According to my invention I form polished inclined planes on the wings of the lever
so that when the balance swings round beyond the normal distance, say 300 degrees
of motion the point of the ruby pin touches the bottom of the inclined plane and is
allowed by means of a spring, which I will presently describe, to press the lever and
travel over it. Immediately the ruby pin has passed over the depressed lever the
spring causes it to fly back to its normal position and it is ready to give the required
impulse to the balance on its return vibration.
Sometimes instead of making the lever resilient I make the ruby pin resilient by
fixing the ruby pin in a spring that is firmly attached to the rim of the balance the
balance staff passing through a small hole in the spring.
When the inotion of balance is increased sufficiently the point of the ruby travels
up the inclined planes on the wings of the lever and rises until it has passed over the
top of the incline the pin then flys back ready to receive impulse on its return.
I will now describe three different ways in which the resilient spring may be applied
to the lever to make the lever resilient, 1st I file down the steel lever from the
guard pin to the pallet staff until it becomes a thin blade and I then make it specially
thin near to the pallet staff, which is pivoted in the usual way. 2nd I fix a thin
blade of steel by one end to the lower plate of the watch and the other end covers the
lower hole of the pallet staff. The pallet staff pivots are made extra long with
abundant end shake. But the spring presses up the pallet staff to its normal position
and makes the end shake exactly right. When the ruby pin travels over the incline
planes on the wings of the lever in the manner referred to the spring yields which
allows the ruby pin to ride over the lever.
3rd. Under the lower hole of the pallet staff I form a cylindrical recess in which I
place the end stone and over it a spiral spring which is kept in its place by two jewel
screws projecting over the hole. When the ruby pin travels over the inclines of the
lever the spring yields and the bottom stone, pallet staff and lever all descend to allow
the ruby pin to pass.
Dated this 24th day of September 1888.

page_text: COMPLETE SPECIFICATION.
Improvements in Escapements for Lever Watches and other
Timekeepers.
I, RICHARD WHITTAKER late of 40 and 41 Kirby Street, Hatton Garden and now
of 25 Hatton Garden in the City of London Watchmaker, 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:-
The object of my invention is to overcome the defects which are known by watch-
makers, as the banking errors which often take place when the watch receives any
sudden movement, which causes the balance to revolve so far that the impulse pin
reaches the jaws of the lever a second time in one direction which generally produces
some disturbance of rate and possibly fracture. In resilient escapements as hitherto
made to avoid this result the lever is allowed to move further under such second action
of the impulse pin. In my invention the lever is made to yield in the direction at
right angles to the plane of motion, or else the impulse pin itself yields end ways.
I form polished inclined planes on the upper faces of the wings of the lever and
either that end of the lever or whole of it is male capable of yielding by a spring as
will be described presently, so that when the balance swings round far enough to
make the pin touch the lever again, it touches the bottom of the inclined plane and
depresses the lever, or that end of it and travels over part or the whole of that inclined
plane. If the pin travels over the whole of the plane, the lever end rises again and
the notch is ready to receive the pin on its return. If it does not travel so far the
lever simply rises again as the pin recedes.
Instead of making the lever resilient the ruby pin may be made resilient by fixing
it in a spring attached to the rim of the balance, the balance staff passing through a
small hole in the spring. In that case if the pin reaches an inclined plane, it rises
up the incline until it has passed over the whole or part of that plane and then
returns.
I will now describe three different ways in which the resilient spring may be applied
to the lever 1st I file down the lever from the inclined planes to the pallet staff, until
it becomes a thin spring capable of yielding to the pressure of the end of the pin as
above mentioned.
This arrangement is shewn in Figure 1 which is an underside view much
magnified.
I will first give a general description of this figure and then explain its novel
features.
a is the escapement wheel and a¹ its axis. is the pallet staff and c the anchor or
pallets fixed upon the pallet staff. The pallets are jewelled as usual with rubies c¹ c¹;
d is the balance staff on which is the balance. e is the roller also on the balance staff
and it carries the impulse pin of ruby f. The whole piece g. 9 &c. is the lever carried
by the pallet staff, it is fixed to the anchor by the pins gx gx. g¹ is the notch which
receives the ruby. gg are the wings or horns of the lever. h. h are banking pins
which limit the movement of the lever. is the guard pin fixed into the lever, it is
not in contact with the roller but so near to it as to prevent tripping, that is to say,
the lever can only move from side to side when the guard pin is opposite the crescent
made to receive it in the periphery of the roller. Now in the arrangement shown by
this figure the end of the lever g upon which the impulse pin acts, and on which the
wings are provided is not rigidly connected with the pallet staff but it is a spring, and
is capable of yielding in a direction at right angles to the plane in which the lever
normally vibrates.
The horns or wings 92 of the lever g are formed with inclines upon their upper
surfaces as is seen in Figure 2 which is an end view of the lever g. The action is as
follows if the balance staff rotates through more than its normal angie and so far as
to bring the impulse pin into contact with the end of one of the horns or wings of the

page_text: lever, then the end of the pin will pass along the incline pressing down the wing
out of its way; and this may go on either until the impulse pin has passed entirely
over the horn or until the pin commences its return journey. Figure 3 is a side
elevation of the parts as they appear when operating normally. Figure 4 shows
them when the rotation of the balance staff is abnormal and the impulse pin comes
on to the incline of the horn or wing and thereby deflects the end of the lever.
b is a collar in the pallet staff which serves to protect the spring part of the
lever from accidental injury when the watch is being cleaned.
The crescent in the roller e must be a trifle larger than usual; it must be so large
that when the impulse pin, has by excessive motion ascended the incline plane, the
guard pin in the lever must be well within the crescent, so that if the motion of
the balance be arrested at this point, and the balance commence its return journey,
it cannot press the guard pin i against the edge of the roller.
The width of the wings of the lever should be not less than the diameter of the
impulse roller; these proportions are fairly shown in Figure 1.
I would remark that in the Figures 2, 3 and 4 the inclines upon the wings are
for greater clearness shown much steeper than they would be made in practice;
an incline of 7 or 8 degrees is sufficient and in a watch the distance which the
horns yield to allow the pin to pass over them need not much, if at all, exceed roo
of an inch.
Figures 3 and 4 show a lever and anchor of a somewhat different shape but
acting in all respects as already described.
The inclines should yield to the impulse pin freely so that if the energy of
the balance be exhausted whilst the end of the pin is upon the incline there may
be no risk of the impulse pin stopping on the incline but a certainty that it will be
drawn back down the incline by the pendulum spring.
There is as will be observed no dead point on which the impulse pin can jam
or set.
The form of escapement just described gives excellent results and is perhaps to
be preferred to the modifications which I will now explain.
A second way is shown by the Figures 5, 6 and 7. I fix a long spring by one
end to the lower plate of the watch and the other end covers the lower hole of the
pallett staff. The pallett staff pivots are made long enough to allow the staff to rise
and fall and the spring presses it up to its normal position whenever it is not yielding
to the pressure.
Figure 5 is a plan and Figures 6 and 7 are side elevations; the latter figure showing
the abnormal position when the impulse pin comes against the end of the horn or wing
of the lever and travels over the incline.
In this arrangement the lever is rigid and fast upon the pallet staff but the pallet
staff is capable of endwise movement.
m is a
k is the lower plate of the watch; in it the jewel is fixed in the usual way.
long spring fixed to the plate, its end covers the hole in the jewel. b is the pallet staff
and is its lower pivot, it is supported by the spring and so the pallet staff is held up
to its proper working position. But when the impulse pin strikes the horn or wing
of the lever, the lever and the pallet staff are pressed down by the operation of the
incline, the spring m yields, the pin passes over the horn and the parts assume the
position represented in Figure 7.
A third way is illustrated by Figure 8.
Under the lower hole of the pallet staff I form a cylindrical recess in which I place
the endstone and under it a spiral spring which is kept in its place by two jewel
screws projecting over the hole. When the pin travels over the inclines of the
lever the spring yields and the bottom stone, pallet staff and lever all descend to
allow the pin to pass.
Figure 8 is a section greatly magnified.
n is the lower plate of the watch. o is a perforated jewel fixed in it; this jewel
receives the lower pivot 6° of the pallet staff, p is an endstone supporting the pivot.
g is a coiled spring keeping the end stone in place and rare screws which serve to

page_text: secure the spring. The action is the same as in the arrangement shown by the
figures 5, 6 and 7.
In place of arranging that the lever shall be able to yield to the impulse pin, the
pin itself may in like-manner be made to yield to the lever and move end wise in order
to pass the wings or horns.
is the balance wheel fixed upon it.
Figures 9 and 10 show such arrangements.
d is the balance staff and
g is the lever, with
its wings and inclines as before but it is rigid upon the pallet staff b. The impulse
pin is carried by a spring arm d² fixed to the balance wheel so that the pin can
yield and pass when it comes against the incline on the wing or arm of the lever.
figure 9 the spring arm is long and the pallet staff passes through it. In Figure 10 a
shorter arm is used, which is simpler but the arm is less flexible.
In
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
1. Lever escapements arranged substantially as described in such manner that when
the impulse pin, after a vibration of undue amplitude strikes the horn or wing of the
lever, it may be able to pass, by a yielding either of the pin or lever or a part of the
lever in a direction at right angles to the plane of the movement of the lever so that
the impulse pin and the wing or horn of the lever pass in different planes.
2. A lever escapement with inclines upon the horns of the lever surfaces which are
inclined to the staff or axis and which are operated upon by the end of the impulse
pin and then cause a displacement of the parts permitting the impulse pin to pass the
horns.
3. Resilient escapements substantially as described and illustrated by the annexed
drawings.
R. WHITTAKER.