AN IMPROVEMENT IN THE MANUFACTURE OF ESCAPEMENTS FOR CHRONOMETERS, CLOCKS, AND WATCHES
Year: 1838

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JosErit
EDEN MACDOWALL, of No. 257, High Street, Borough, Watch Maker, send
greeting.
WHEREAS Her present most Gracious Majesty Queen Victoria, by Iler
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fifteenth day of November, in the second year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said Joseph
Eden Macdowall, Her especial license, full power, sole privilege and autho:ity,
that I, the said Joseph Eden Macdowall, my exors, admors, and assigns, or
such others as I, the said Joseph Eden Macdowall, my exors, adors, or
assigns, should at any time agree with, and no others, from time to time and at
all times during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of Berwick-
upon-Tweed, my Invention of "AN IMPROVEMENT IN THE MANUFACTURE OF
ESCAPEMENTS FOR CHRONOMETERS, CLOCKS, AND WATCHES;" in which said Letters
Patent is contained a proviso, that I, the said Joseph Eden Macdowall, shall
cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, to be inrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Joseph Eden Macdowall, do hereby declare the nature of my said Invention,
and the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawing hereunto annexed, and to the figures and letters marked thereon,
that is to say :-
According to the ordinary modes of constructing an escapement there is
a wheel of several teeth employed, and one tooth is allowed to escape at a
time, as is well understood, and on the accuracy of forming each of the said
teeth the going of the watch, chronometer, or clock depends; hence, the
greater the number of teeth of such escapement wheel must materially cause
a greater difficulty in making the same with that accuracy which is desirable.
Now, the object of my Invention is to reduce the number of impulses by
which the escapement axis is caused to make a revolution, and by means of
my Invention such impulses may be reduced to one for each complete revolution
of the escapement axis, and in no modification can an escapement according
to my Invention with advantage exceed three impulses for each complete
revolution of the escapement axis. I would remark, that the great object of
my Invention is to reduce the number of impulses to obtain a revolution of the
escapement axis, and a very important difference exists in any escapement
made according to my Invention over those previously resorted to,, inasmuch
as the escapement according to my Invention has a constant movement for a
considerable portion of the escapement axis, and in some cases, where only
one impulse is given for one revolution of the escapement axis, it is at all times
in action during the complete revolution of such escapement axis, whilst in
other cases the action is continuous over a half or one-third of the revolution
of the escapement axis, according to whether the escapement axis completes
a revolution by one, two, or three impulses; all which will readily be under-
stood on examining the Drawings hereunto annexed, aided by the following
description:-
:-
Description of the Drawing of improvement of escapements of watches,
clocks, and other timekeepers.-A, balance; B, balance axis; C, the cylinder;
D, ruby fixed upon the axis; E, the inclined plane, which passes around the
axis, as shewn in the Drawing; F, screw axis; G, projecting flange of the screw,,
which is continued nearly once round its axis; I, locking piece, fixed fast upon
the hollow pinion II, and made fast upon the screw axis, so as to admit of
being turned right or left; K, a bird's-eye view of the same. 1, 2, 3, 4,
supposed parts of contact when the screw, and the inclined plane are brought

page_text: into contact with each other, as in Figure. 2, which shews the correct position
when-working.
Figure 2. Suppose 'ar power to be pressing- upon the pinion H, suppose
also the lever I- to be locked upon the ruby D, the moment it unlocks,
the flange G of the screw. F will roll itself down the inclined plane E, which
is made fast upon the cylinder C; and consequently impel the balance forward
and -lock again upon the ruby D; the lever I having made one revolution in
the same space of time that the screw rolled down the inclined plane. It must
be observed, that three diameters, or nearly so, is the space of contact upon the
cylinder which is to be passed over by the screw. The number of degrees of
impulse will depend upon the quantity of space which the inclined plane
extends over on the cylinder, thus any number of degrees of vibration may be
obtained by the number of degrees of impulse, and this again will depend upon
the diameter of the revolving lever F; G. A screw with one turn in the eighth
of an inch may be made to perform as well as a screw with one turn in one
inch, if the proper angles of the impeller and the impelled be nicely associated;
any alteration in the length of the screw will directly alter the inclination of
the plane.
Figure 3, showing the action of the double screw.-A, balance, by which
the escapement axis is caused to make a complete revolution by two
impulses; B, axis; C, the cylinder; D, ruby; E, inclined plane; F, M, G, a
double screw; I, L, the double locking piece; H, the hollow pinion, made fast,
as in Figures 1 and 2; K, L, bird's-eye view of the locking I, L. The dif
ference between the single and the double screw is that the latter can be made
half as flat again as the single one and yet retain the same angle, the double
screw making two impulses in its revolution and the single screw only one;
thus it will be seen that the same principle is maintained in Figure 3 as exists
in Figures 1 and 2, the locking and screws differing only in numbers. Figure 4,
bird's-eye view of the cylinder C.
Figure 5, the application of the principle to the propelling of a pen-
dulum, as in a clock. The screw is made to extend across the frames,
in order to exhibit the principle correctly.-A, verge; B, C, inclined plane,
which is impelled by the screw and made fast upon the verge; E, the screw
lever for locking; L, hollow pinion, made fast on the screw; D, F, G, wheel
and pinion of the train, supposed to be propelled by the ordinary weight
or spring; M, the locking end of the verge that receives the lever E every
beat, this lever is made fast to the screw D, one end of which comes through
the plate; K, the crutch which propels the pendulum H.

page_text: Figure 6 shews a method of making watches extremely flat on the same
principle. A, an expanding lever, whose beginning of impulse is at the
figure 0, and which continues to expand and propel the balance, as shewn
by numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, and concludes at figure 10, leaves the
roller revolving in the direction of the arrow; G, C, is a lever projecting
from the axis of the balance D, having been made fast so as to be moved right
or left; B, a small roller, fixed so as to move freely in the lever C, and to
revolve upon its own axis. Suppose a power to be applied to the axis of
the expanding lever A, it will cause it to move and to begin the contact
at the figure (0) upon the roller B, fixed in the lever C, and consequently
push the balance forward to the right until the point (10) of A, as seen by
the dotted circle F, and will have arrived at its quiescent position as at
present drawn, the locking lever falling upon the ruby cylinder, as described
in plan the first figures (1), (2), and (3). The balance baving received its
impulse will vibrate to the right, return to the left, move again to the right,
unlock and receive the power from the expanding lever A, and so continue
its vibrations.
Figure 7 shews a side view of Figure 6.-A, an expanding lever, made fast
upon the axis H; F, F, two views of the lockings fixed fast upon the
pinion G; D, the balance; K, balance axis; C, the impelled lever; B, the
roller; I, the pinion before the locking piece is made fast upon it. The
revolving lever A is pressed tight on at H, so as to be moved to the right or
left. In arranging the escapement, suppose the fifth wheel of the train to
impel the pinion G, the same effect will be accomplished as described in
Figure 6.
Figure 10 shows a clock on the same principle.-A, the expanding lever;
F, the locking lever; E, the cylinder that receives the locking lever; B, the
friction roller; C, the lever which is connected with the crutch that impels
the pendulum, as in Figure 5, thus it will be seen that any length of lever
can be obtained for a clock, and the friction in proportion reduced. A
double lever may be made upon the same principle, keeping in mind the
proper curve, which must gradually expand from the centre and the locking,
which must be double.
Figure 11 shows the method of locking the clocks for the royal pendulum,
or longer ones, requiring less vibration.-A, the lever made fast upon the same
axis as the impelled lever is fixed upon, having a little notch cut in its centre,
as at C, in order to let the locking lever B pass from a state of rest.
Figure 12 is another arrangement for propelling pendulums and balances

page_text: upon the same theory, making one or two revolutions every time the propelling
lever strikes the balance or pendulum. A, the verge; B, the last pinion of the
train, one end of which comes through the back plates, as at C; D, the pin
that propels the lever E; F, the clutch, as in common clocks; the letters
E, D, and C, a front view of the same parts.
Figure 13 shows the application of this method to a watch.-B, the
circle made fast upon the axis of the balance A; H, the ruby pin, pro-
pelled by the long end of the lever F; E, the other end of the lever, where the
pallets are formed as in Figure 12, only differing in their distance from the
centre of motion; D, the pin made fast in the small wheel C. The power
applied giving motion to the wheel C, the method for propelling the balance is
the same as the one now in use called the detached lever escapement; and I
would remark, that the inclination of the screw may be to the right or left,
only the inclined plane in the cylinder must be arranged as I have described
in the Drawing. The train must be greater in number than other chronometers,
watches, clocks, &c., in consequence of the quicker motion in the train between
the fourth wheel and the revolving lever; suppose the fourth wheel to be
ninety, the fifth wheel pinion six, the wheel sixty, pinion six, which is fixed upon
the revolving lever, 15 x 20, three hundred beats per minutes. Supposing the
the fourth wheel marking seconds, when the revolving lever is double the train
will be lower in number. The locking I do not claim as mine, it is the same
as the duplex watch, being the one I have placed in the Drawings, any lockings"
may be used, as the maker may think proper.
Having thus described my Invention, I would remark that the great object
of my Invention has been to attain a complete revolution of the escapement
axis for each impulse. At the same time, as the peculiar properties of my In-
vention offer advantages over the previously used escapements when extended
to two impulses for one revolution of the escapement axis, I have shown the
Invention as arranged for accomplishing with two impulses for one revolution;
and it will be evident that the Invention might be still farther extended to
three impulses for each revolution, and yet be superior to the ordinary escape-
ments now used; but I consider that any departure beyond two impulses for
each revolution of the escapement axis is to the prejudice of my Invention, the
main object and advantage of which is the dispensing with the escapement
wheel of many teenth heretofore employed, and applying a suitable instrument
to the escapement axis, in order to obtain a complete revolution of such axis
for each impulse, by which I not only decrease the possibility of the work-
man's errors of workmanship, but also have the further advantage over the

page_text: naking of the escapements now..employed, inasmuch as a workmans of much
ess ability may make escapements according to my Invention, and produce
resultisuperior. for correctness over the escapements now employed, which
equire the skill, of.first-rate workmen.
In witness whereof, I, the said Joseph Eden Macdowall, have hereunto
set my hand and seal, this Fifteenth day of May, in the year of our
Lord One thousand eight hundred and thirty-nine.