Year: 1887

page_text: 1 HEZEKIAH CONANT of 69 Clay Street Pawtucket in the County of Providence
and State of Rhode Island United States of America Manufacturer; 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 provide a new and improved time-measuring
instrument which is practically isochronal.
The invention consists of two or more independent escapements connected with a
single clock train in such a manner as to indicate or shew on a main dial, the average
time of the several associated escapements.
The Invention also consists in the construction and arrangement of various parts
and details and combinations of the same, as will be fully described hereinafter, and
then pointed out in the claims.
Reference is to be had to the accompanying drawings forming a part of this
specification, in which similar letters of reference indicate corresponding parts in all
the figures.
Figure 1 is a front elevation of my improvement.
Figure 2 is an enlarged front elevation of the dial plate, parts being broken out.
Figure 3 is a front elevation of the clock movement with the dial plate removed.
Figure 4 is a vertical cross section of my improvement on the line - of
Figure 3.
Figure 5 is a sectional plan view of the same on the line y-y of Figure 3; and
Figure 6 is a central section of part of my improvement on the lines - of
Figure 5.
It is a well known fact that two or more independent escapements, however well
regulated, differ, in indicating the time. The object of my invention is to make use
of this difference between two or more independent escapements, and to transmit this
difference by the mechanism presently to be described, to a main shaft indicating an

page_text: average time of several associated escapements, thus reducing the incorrectness of the
several escapements to a minimum.
My improvement is based on the idea that the average of four nicely adjusted
movements would show a variation of only one-sixteenth of what any one of them
would show in the same time, as some of the errors would offset other errors, so that
if one is a trifle too slow and another too fast the average will be correct time. The
escapements are so combined and impelled that they are substantially independent of
each other and one will run whether the others are idle or not.
In carrying out my invention in practice, I can employ escapements_of any approved
construction, either pendulum balance wheel or other escapements. In the drawings
and the following description, I show and refer to pendulum escapements, but it is
understood that any escapement may be used.
My improvement is mounted in the casing A, which supports the clock frame B,
in which is journaled the driving shaft C carrying the usual drum C¹ which may be
rotated in any suitable manner, either by springs or weights.
The driving shaft C is connected by a train of gear wheels D with the second
shaft E, carrying on its outer end the seconds hand E¹ indicating seconds on the
dial F which is divided into twelve hours and sub-divisions. The shaft E is also
connected in the usual manner, by a train of gear wheels, with the sleeve G carrying
the minute hand G¹ indicating the minutes on the dial F, and the said shaft is, in a
similar manner, connected with the sleeve I carrying the hour hand H³, indicating
the hours on the said dial F. The several connections as outlined above, are common
to almost all clocks, and a detailed description is deemed superfluous.
On the shaft E is secured the gear wheel I, which meshes into the gear wheel I'
secured to the shaft 12 mounted in suitable bearings in the clock frame B. In the
web of this gear wheel I' is mounted a shaft I3 standing in radial line with the axis of
the shaft. I and carrying the beveled planetary gear wheel J meshing on one side
into the beveled gear wheel K mounted loosely on the shaft I2, and the beveled gear
wheel J meshes on its other side into a beveled gear wheel L also mounted loosely on
the said shaft I², see Figure 6.
On the beveled gear wheels K and L are formed the spur wheels K¹ and L'
respectively, and the spur wheel K' meshes at its left side into an intermediate gear
wheel K², which meshes into the gear wheel N secured to the shaft N¹ mounted in
suitable bearings in the clock frame B. On the gear wheel N is mounted, on a radial
shaft, a beveled planetary gear wheel O, which meshes on one side into the beveled
gear wheel P turning loosely on the said shaft N', and the other side of the planetary
gear wheel O meshes into the beveled gear wheel Q also loosely mounted on the
shaft N¹.
On the beveled gear wheels P and Q are formed the spur wheels P¹ and Q¹
respectively, of which the spur wheel P¹ meshes into the pinion P² secured to the
escape wheel shaft P3 carrying the escape wheel P4 actuating the one second
pendulum P of any approved construction. The outer end of the escape wheel
shaft P3 carries the second hand Pe indicating on the seconds' dial P' located below
the dial F to the extreme left.
The other spur wheel Q¹ meshes into the pinion Q2 secured to the escape wheel
shaft Q3 carrying the escape wheel Q actuating the one second pendulum Q³ of any
approved construction. The outer end of the shaft Q³ carries the second hand Q
indicating on the seconds' dial Q7 located to the right of the dial P' below the dial F.
The arrangement on the right hand side of the gear wheel I' is the exact counter-
part of the mechanism above described on the left hand side of the gear wheel I¹,
inasmuch as the gear wheel L'.meshes into the intermediate gear wheel L2, which
meshes into the gear wheel R carrying a planetary beveled gear wheel S meshing
into the beveled gear wheels T and Ŭ respectively, and on which are formed the spur
wheels T¹ and U₁ respectively. The spur wheels T¹ and U mesh respectively into the
pinions T2 and U2 secured to the respective escape wheel shafts, T3 and U³, carrying
the escape wheels T* and U, actuating the one second pendulums T5 and U
respectively.

page_text: The escape wheel shaft T3 carries on its outer end the seconds' hand T indicating
on the seconds' dial T located to the right of the dial Q On the other shaft U³ is
also secured a seconds hand U indicating on the dial U³ placed to the right of the
dial T.
The operation is as follows:
The rotary motion of the shaft E is regulated by the average speed of the four
escapement wheel shafts P³, Q³, T3 and U³, each of which makes a revolution once in
every minute and indicates each beat of the pendulum in seconds by its respective
hand on the respective dial P, Q, T, U. The difference in motion between the four
escapement wheel shafts is very slight, but the difference, whatever it may be, is
diminished to one-sixteenth on the shaft E, which, when all the escapements are
going, travels at the rate of one minute for every revolution. But when one of the
pendulums and its escape wheel shaft is stopped, then the result on the shaft E is only
three-fourths of a revolution in a minute, and if two pendulums are stopped, the main
shaft E and its hand E will go at half rate, and if only one pendulum is allowed to
run, this hand E' on the main shaft E will record one minute in four minutes time,
thus showing that the variation of any pendulum effects the main movement only one-
quarter of such error.
Each escapement has a seconds' hand of its own to show its own rate, and thus can
be properly regulated so that if one loses more time than it ought, then it is regulated
to keep to its proper speed. The main shaft E imparts, by means of the gear wheel I,
motion to the gear wheel I', which carries with it in its rotation the planetary beveled
gear wheel J.
The latter, by being carried by the rotating gear wheel 1', imparts rotary motion
at the same time to both double gear wheels, K, K1, and L, L'. Each of the gear
wheels K, K and I, L', imparts, by means of the respective intermediate gear
wheels K2 and L³, a rotary motion to the gear wheels N and R respectively. As
each of the latter carries a beveled planetary wheel which acts on two double beveled
gear wheels in the same manner as above described in reference to the beveled
planetary gear,
J, it will be seen that a rotary motion is imparted to the respective
escape wheel shafts with which the said beveled gear wheels are directly
connected.
Now, as the motion of each escape wheel shaft is regulated by its respective
escapement and each motion differs however slightly, from the other, it follows that
this difference in speed is transmitted to the respective two sets of double gear
wheels, P, P, Q, Q and T, T, U, U. The average speed between the two beveled
gear wheels of each set is imparted to the beveled planetary gear wheels and S
respectively, which turn on their respective axes, and, on account of being held in the
gear wheels N and R, impart their average motion derived from the respective seis
of beveled gear wheels to the said gear wheels N and R.
Thus, it will be seen that the gear wheels N and R travel at the average speed of
their respective sets of double gear wheels. The gear wheels N and R being connected
by the intermediate gear wheels K and L2 respectively with the set of double gear
wheels K, K¹ and L, L', impart to the latter their respective average motion. The
difference of speed, however small it may be, between these two sets of double gear
wheels is imparted to the beveled planetary gear wheel J, which imparts its average
motion derived from the said set of double gear wheels K, K' and L, L' to the gear
wheel I', with which it turns. As the latter gears directly into the gear wheel I, it
will be seen that the shaft E carrying the latter gear wheel I, travels at the rate of
one second inotion subject to the average speeds of the four escape wheel shafts P³, Q³, T³
and U, the independent motion of each of the latter being indicated on the
dials P, Q, T, and U7, while the average motion of the four is indicated on the
dial E in seconds, minutes and hours.
It will be seen that if the two wheels L, L, and K, K' receive an impulse from
the wheel I' through the medium of the planetary wheel J, see Figure 6, then the
wheel I carrying the said planetary wheel J, must, in the first instance, be supplied

page_text: by a power equal to the power required to propel the two escapements, connected
with the beveled gear wheels L, L' and K, K', and at the same time the wheel 'I' will
move forward at an average speed of the two beveled gear wheels L, L' and K, K
connected with the escape wheel shafts. It is evident from this that the power
applied to the main shaft E must be sufficient to propel the four escapements, and
consequently will be acted upon with a force having fourfold the power of the ordinary
one, and is hence, less liable to be affected by imperfection in the mechanism operating
on the said main shaft E. Thus, this extra power given to the main shaft E over-
cones any slight frictional obstructions, whereby the resultant of the arrangement
is a strong motion without danger of increasing the abrasion at points of the
escapement.
G
To illustrate the action of this instrument more clearly, it is supposed that the
pendulums are at rest, and the second hands P, Q, T and U of the escapements and
the second hand E¹ on the main shaft E all point exactly alike, at zero on their
respective dials. Now, if one pendulum is started alone, the second hand on its
escapement shaft will mark seconds on its dial while the second hand on the main
dial, although responsive to the same and moving synchronally with it will move only
one-fourth of a second at each beat, and will make one revolution, while the former
has made four. Now let a second pendulum be started and the effect will be that the
respective escapement gear wheel will move the second hand on the main dial at each
beat one-fourth of a second, so that as the other going pendulum moves the second
hand on the minute dial also one-fourth of a second at each beat, the effect will be that
the speed of the second hand on the main dial will be double, that is one-half of a second
at each beat of the two pendulums; three pendulums moving will triple it, and when
the four pendulums are in action the main train is at full speed, and the speed of the
main second hand is exactly the average of the combined speed of the four escape-
ments. Thus it will be seen that the variation of speed or error in time of one
escapement affects the movement of the main frame only one-fourth of such error,
and as it is not likely that the same errors would occur in different escapements
simultaneously and be of the same character as well, it is safe to say that this associa-
tion of the escapements with a single clock train will reduce the errors to a fraction
indicated by the square of the number of pendulums and escapements employed; thus
if two pendulums or escapements were employed, it would reduce liability of error to
one-fourth or four to one-sixteenth, and eight to one-sixty-fourth, and so on, by
reason of the chances of one error off-setting another, and also by the increased power
of the main train rendered necessary by the multiplicity of the escapements.
Having now particularly described and ascertained the nature of the said Invention
and in what manner the same is to be performed, I declare that what I claim is :
1. In an isochronal clock the combination with two or more escapements, of a main
shaft and a clock train connecting the said escapements with the said main shaft in
such a manner that the main shaft indicates the average time of the said escapements,
substantially as shown and described.
2. In an isochronal clock, the combination with a main shaft, of independent escape-
ments and a differential mechanism, substantially as described, for transmitting the
average motion of the said escapements to the said main shaft as set forth.
3. In an isochronal clock, the combination with a main shaft actuated by suitable
clock work, of independent escapements actuated from the said main shaft, and a
differential mechanism, substantially as described, for transmitting the average
motion of the said escapements to the said main shaft, substantially as shown and
described.
4. In an isochronal clock, a main shaft actuated by suitable clock work, a hand
held on the said shaft and a dial on which indicates the said hand, in combination with
independent escapements actuated from the said main shaft, a hand operated by each
escapement, dials on which indicate the said escapement hands, and an intermediate
differential mechanism, substantially as described, for transmitting the average motion

page_text: of the several escapements to the said main shaft, so that the latter, by its hand,
indicates the average time of the said escapements and their hands, as set forth.
5. In an isochronal clock, a shaft, a gear wheel secured on the said shaft and a
beveled planetary gear wheel held on the said gear wheel, in combination with two
beveled gear wheels held loosely on the said shaft and meshing into the said beveled
planetary gear wheel and escapements connected by suitable means with the said
beveled gear wheels, substantially as shown and described.
6. In an isochronal clock, a main shaft actuated by suitable clockwork, a pinion
secured on the said shaft, a gear wheel meshing into the said pinion, a shaft ou
which the said gear wheel is secured, and a beveled planetary gear wheel held on the
said gear wheel, in combination with two beveled gear wheels meshing into the said
beveled planetary gear wheel and being held loosely on the said shaft, and independent
escapements connected by suitable means with the said beveled gear wheels, substan-
tially as described.
H. CONANT.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.