IMPROVEMENTS IN APPARATUS FOR OBTAINING ISOCHRONOUS MOVEMENTS APPLIED TO CLOCKS AND OTHER TIMEKEEPERS
Year: 1867

page_text: PROVISIONAL SPECIFICATON left by William Clark at the Office of the
Commissioners of Patents, with his Petition, on the 12th April 1867.-
A communication from abroad by Joseph Pizzocheri, Clock Maker to
the Royal Family of Italy, of 29, Boulevart St. Martin, Paris.
I, WILLIAM CLARK, of 58, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN APPARATUS FOR OBTAINING ISOCHRONOUS MOVEMENTS
APPLIED TO CLOCKS AND OTHER TIMEKEEPERS," to be as follows:-
This Invention relates to an improved escapement for regulators and other
large timekeepers; this escapement is rendered isochronous in its action by
the aid of pendulums, which regulate the time without the aid either direct
or indirect of the clock motion, except that the power of the same is
accumulated in springs, by the aid of which the isochronism is obtained.
Whatever may be the system of escapement employed perfect isochronism can
only be obtained with the pendulum completely at liberty on the old systems.
The pendulum during its double oscillation effects contact at least three times,
producing so many causes of friction, that is to say, so many causes of
irregularity, while, according to these improvements, by employing two
pendulums working reciprocally and with neutral movements, there is only
one slight contact during the double oscillation.
By the arrangements of this Invention which are illustrated in the

page_text: accompanying Drawings the pendulum is allowed perfect freedom, the
invariability of the oscillations ensuring perfect isochronism and each
oscillation being mathematically equal to the preceding or following one.
Figure 1 of the Drawings shows a partial plan of the arrangement;
Figure 2, a partial elevation; Figure 3, a partial elevation to the left of
Figures 1 and 2; Figure 4 a similar view to the right of Figures 1 and 2 ;
Figure 5 is a section of the spindle b on the line 1, 2, Figure 1; Figure 6, a
similar section on line 3, 4, Figure 1; Figure 7 is a similar section on the
line 5, 6; the same letters serve for all the Figures.
a, pinion for transmitting motion from the motor, which may either be a weight
or coiled spring; b, spindle or axis of pinion a on which it is mounted; c, tooth,
pallet, or eccentric formed on spindle b, Figure 6 showing a section of the same;
d, similar tooth, but disposed on the opposite side of axis b, Figure 7 showing
its form in section; e, two pins mounted eccentrically on axis b, also shown in
section, Figure 5; f, oscillating lever; g, link connecting lever f with the tail
end of a lever h, the motion of which is limited by a stop q; i, two bent arms
cach mounted on a part j and working on axes ; k arms for stopping the
clock motion mounted on axis ; l, stopping arm of the pendulum; m, stop
mounted on axis n and carrying the arm 1; n, axis of the second detent; o,
spring bearing on a lever p mounted on axis n; when in a state of rest the
spring o bears on the stop picce m. r, projection acted on by a suitable
springs and serving as a stop for the clock arm k; t, axis of the first detent
carrying the two bent arms i as also the lever r; u, flyer mounted on
axis b which by the pressure of the spring arms is brought in frictional contact
with the arms k of axis b; this pressure is regulated by a pin passing through
the axis ; v, disengaging arın; a, arm for regulating the position of the
pendulum at starting in relation with the toothed end of arm i; y, pendulum
arm; the distance of the arms v, y, from arm is regulated by the adjusting
screws 8 bearing on its upper part, said part x is
also fixed to the pendulum;
9, springs imparting a certain amount of elasticity to arms v and y, in order to
bring them back to position, they being mounted on axes 10 of the pendulums
or balances 11. 12, tappets mounted on arms v forked at their ends as seen in
plan at Figure 1, in elevation at Figure 2, and laterally at Figure 3; 13, arm
serving to bring back the tappet 12 to the vertical position occupied in Figure 2.
The two pendulums or balances being placed in a vertical position I first
move the binder pendulum to the right and then release it when it
immediately returns to the left and effects its one contact, so producing what
1 terin the first preparation, as seen in Figure 2 where the hinder pendulum
is shown in gear. This preparation is effected as a'ready mentioned by

page_text: acting on the pallet of the second detent, which causes the first to escape
instantaneously, whence results the depression of the tappet, on which the
pendulum will naturally become freed simultaneously with the freedom
imparted to the clock motion, which latter, before returning the first detent
to position by the aid of the eccentric pins e liberates the pendulum which bas
already passed the pallet of the second detent freely, so that the tappet is
not subjected to any contact while moving from right to left and effects but
one contact in passing from left to right; the other movements of the various
parts take place uniformly one after the other. The front pendulum is
moved in a similar manner to the first mentioned to the right hand, which
when released returns to the left and effects its one contact. From this
results the same preparation as before, there being a simultaneous release
of the clockwork and pendulum, which latter is free to measure the time and
in passing from this to a neutral movement it is prepared to again become
freed, and so on, the measure of time is thus rendered invariable.
The Invention thus consists in an improved escapement with two reciprocating
pendulums, which have never hitherto been employed. In all so called
detached escapements the motive wheel is in all cases in connection with the
pendulum while it is describing an arc of a circle of greater or less extent.
The same is the case with constant acting pendulums which effect contact at
three points during each double oscillation, while according to the arrangement
of two pendulums of this Invention there is only one very slight contact which
is without influence on the regularity or the motion, and by which invariabilty
in the measurement of time is obtained.