Improvements in Compensating Pendulums.
Year: 1890

page_text: Date of Application, 16th Sept., 1890-Accepted, 10th Jan., 1891
COMPLETE SPECIFICATION.
Improvements in Compensating Pendulums.
I, CHARLES E. EMERY, of 370 Greene Avenue, Brooklyn, in the County of Kings
and State of New York, United States of America, Engineer, 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 :-
These improvements relate to that class of pendulums in which the compensation
is secured by the use of a compound rod made of materiais possessing different degrees
of expansibility by heat and in which the connection between such rod and the ball of
the pendulum is made through a lever or system of levers. In such pendulums, as
ordinarily constructed, pivots and journals are required, and these, however well
constructed, have more or less friction which interferes with, or prevents, the prompt
movement of the parts required to secure accurate compensation for slight changes of
temperature. In consequence thereof, motion takes place with a minute jump after
the difference of temperature has become sufficiently great to overcome such friction,
and this movement is often so great, even in the best of such pendulums, that they
frequently acquire a gaining or losing rate of several seconds a day after a change of
temperature sufficient to change the compensation, and then, if the temperature varies
only a few degrees, such erroneous rate will be maintained until the temperature
changes sufficiently to again change the compensation when the erroneous rate is
reversed and remains so until another considerable change of temperature occurs.
It will thus be seen that it is practically impossible with such pendulums to secure
accurate compensation for slight changes of temperature, and the primary object of
my invention is to overcome the defects referred to and to produce a pendulum in
which any change of temperature great or small will produce an accurate and
corresponding change in the compensation of the pendulum. To this end, my
invention consists, in general terms, of the combination, with the various parts of a
pendulum of the description above referred to, of flexible metal or spring joints
whereby friction in the ordinary sense of the term is absolutely prevented and it
consists further in the details of construction and arrangement and combination of
parts hereinafter set forth and specificially pointed out in the claims.
Reference is to be had to the accompanying drawings forming part of this
specification, wherein
Figure 1 is an exterior side elevation of a half-seconds pendulum embodying the
distinguishing features of my invention.
Figure 2 is a plan view of the bridge piece connecting the upper portions of the
compound rod.
Figure 3 is a bottom view of the pendulum ball and connection.
Figure 4 is a side view of one of the plates forming the main rod.
Figure 5 is an end view of the pendulum looking from right to left, some parts
being omitted to avoid confusion.
Figure 6 is a similar view thereof, partly in section and looking from left to right.
Figure 7 is an enlarged vertical transverse sectional view on a line drawn through
the centre of the lower part of the main rod A.
Figure 8 is an enlarged side view of the lower part of the main rod A.
Figure 9 is an enlarged side view of the lower part of the main rod A and section
of a portion of the pendulum ball, also shewing the main fulcrum joints in section.
Figure 10 is an enlarged plan, and Figure 11 an enlarged side view, of the upper.
end of the adjusting rod 9 and supporting tube h.
g
Figure 12 is a general front view of a modified construction provided with double
levers and adapted for a full seconds pendulum.

page_text: figure is an enlarged front view, and Figure 14 an enlarged side view of the
upper portion thereof.
Figure 15 is an enlarged front, and Figure 16 an enlarged side, view of the lower
portion of the pendulum.
Figure 17 is an enlarged top view of the upper connecting yoke.
Figure 18 is an enlarged top view of the levers shewn in Figure 15, and also shews
the general position of the upper connecting yoke, with some details omitted.
Figures 19 and 20 shew respectively an equivalent construction of the flexible joints
herein referred to, and
Figure 21 is a detail view shewing the manner in which the upper ends of the
members of the compound rod are connected.
In the construction shewn in Figures 1 to 11, the main rod A is preferably made
up of two plates of brass, or other material possessing a high degree of expansibility,
secured together by pillars or separators to form a frame and offset outwardly at the
bottom to receive the joint mechanism of the fulcrum, as hereinafter described.
The other member a of the compound rod is made of iron, or some other suitable
material possessing a lower degree of expansibility by heat than the member A. The
pendulum ball B is secured to the lower end of the rod a and the upper end of said
rod is supported by the bridge piece b which connects the two plates forming the
main rod A, at their upper ends. The rod a is connected to the pendulum ball Bat
a point between the centre of the ball and the fulcrum C by a flexible joint, so that a
lever is formed within the ball itself. As the ball is supported between its centre and
the fulcrum by the rod a of low expansibility and as the fulcrum is held down at the
outer edge of the ball by the main rod A of greater expansibility, the effect is that as
the temperature increases the main body of the rod A expands more than the central
rod a thereby carrying down the outer or fulcrum end of the lever formed in the
ball B and lifting the centre of the latter so as to compensate the pendulum for
temperature; the reverse action being produced by a reduction of temperature. The
lower separated ends of the plates AA are connected together rigidly by a pillar c,
shewn most distinctly in Figure 7 which pillar, near its ends and preferably inside
the plates A A, receives, in suitable slots, the lower ends of two thin springs s s
secured by rivets, the upper ends of the springs s s are similarly secured to a bar d
resembling in appearance the pillar c but reduced in diameter at its ends d' which
extend loosely into holes in the plates A A, the intention being that such reduced
ends shall not touch the plates except under conditions of unusual strain or jar when
they will operate to prevent the springs ss from being bent sufficiently to become
distorted or injured. The bar d lies in a transverse groove in an arm O formed upon
the ball B of the pendulum and is secured thereto by a screw e, the effect of the whole
arrangement being that the weight of the ball (which is supported, in a way yet to be
· described, between its centre and the fulcrum) tends to lift the outer end at fulcrum C
and, through the screw e and bar d, brings tension upon the springs s 8, which is
transmitted to the outer plates A A of the rod through the pillar c. The upward
strain thus produced is carried to the upper end of the plates A A forming the main
body of the rod and the piece b secured between such plates receives the upper end of
the central rod a which supports the ball at a point between the centre of weight and
the fulcrum, thereby completing the couple and attaching the ball B to the main body
of the rod A. The lower end of the central rod a is preferably secured in a socket f,
Figure 9, and receives in a suitable slot a spring t the lower end of which is secured
in a corresponding slot of an adjusting rod g (Figures 9 and 11) which enters a guide.
tube h secured to a plate i, Figure 1. The plate i rests on a suitable bearing formed
near the bottom of the pendulum ball B and is secured to the latter-through slots in
the plate by screws, as shewn. The lower end of the adjusting rod g is threaded
and carries an adjusting screw; by operating which the centre of the pendulum
may be swung around the fulcrum (thereby changing the relative lengths of
the two elements of the compound bar and at the same time altering the effective
length of the pendulum and regulating the rate of the clock. The upper end
of the rod a is ordinarily threaded and is provided with a nut of which the

page_text: With the
lower part is hemispherical or in the form of an inverted cone and which
enters a hole in the piece b secured to and between the plates A A near the tops
of the same. This hole is of such size that the inclined sides of the base of the
nut will rest on the edges thereof and always he brought to a definite bearing. This
is a very important improvement over the common and extremely unsatisfactory
method of arranging a pendulum rod in a loose hole and so that the nut on same
will bear on a surface not made accurately at right angles to the rod, whereby when
the nut is turned slightly for close adjustments the effective length of pendulum may
be varied more by change of position than by the movement on the thread and
perhaps the desired adjustment be doubled or even reversed in direction.
conical or ball joint above shewn, the parts are always brought to a definite bearing
and even if the angle be slightly changed no variation in length will take place
with a ball-joint and practically none with a cone-joint. When it is desired to
regulate the clock from the top, the nut k is made loose on the thread on central rod a
and provided with a large milled head. To prevent the rods a and g from turning,
the tube h, as shewn in Figures 10 and 11, is provided with a slot on one side at
least, in which slides a pin secured in adjusting rod g at such angle as to cause the
spring to lie in a transverse direction. One of the plates A of main frame is
constructed with two arms having eyes and m, Figure 4, at their ends to which
it is secured (by screws, nuts, and spring washers, shewn in side view Figure 5) a
beat arm E provided at the top with a forked hook engaging with a pin secured to
the lower portion of the pendulum suspending spring n which is secured at its upper
end to a fixed stud o forming part of, or attached to, a cock or frame in any
customary manner. There is a slotted hole in the beat arm E opposite eye m, which
permits the arm to be swung laterally upon a screw in upper eye as a fulcrum but
subject to the resistance of the spring washers previously mentioned. The lower end
of beat arm E is provided with a slotted opening p which receives the crutch wire
connected with the anchor staff of the clock, the end of which is to be bent laterally
for the purpose. As shown in Figure 5, the beat arm E is bent so as to throw the
hook and the portion provided with the slot p on the centre line of the pendulum.
The lower portion of beat arm E is extended down and bent in the form shewn at
which answers the double purpose of preventing the pendulum ball B when being
handled from rising an extreme distance as its edge will come in contact with the
bend and the portion g' of the beat arm extending over and in front of the
pendulum ball can be manipulated when the pendulum is hung in position to shift
the beat arm E and with it the slot p and crutch wire engaging therewith in
relation to the main rod of the pendulum so as to put the clock "in beat," the spring
washers on arms and m serving to retain the beat arm E in the position to which
it may be moved. To the bottom of the pendulum ball a small plate u is attached to
receive weights for close regulation and at the top of the rod a cup v is also secured
to receive weights when it is desirable to make the regulation at the top. A small
weight in cup v located above the centre of suspension to the relative extent shewn,
will slow the clock substantially the same as a similar weight laid upon the table u
at the bottom of the pendulum.
In Figures 12, 13, and 14, o is the cock and n the suspending spring the same as
before. The upper portion of the rod w connects to the spring either rigidly or with
a hook, as in the other case, and is extended below the face of the clock and provided
with any adequate means for engagement with, and adjustment of, the clutch rod a
connected to anchor staff y so that the clock can be put "in beat." One plan is
shewn arranged in the widened part z which is provided with means for connection
to the head F of the pendulum rod. The lower part of this head is connected at the
centre to a rod G of iron or other metal of low expansibility by heat and at the sides
connects to two rods or tubes H H of brass or other material of high degree of
expansibility which support the plates J J (Figures 15 and 16). These plates are
separated by the pillars II to which the lower ends of the rods H are connected. The
outer ends of the plates J J are bent down and receive the pillars c c constructed
like those shown in Figures 7, 8, and 9. Springs ss connect the pillars c c and

page_text: cross-bars d d in a manner similar to that shewn in the said Figures 7, 8, and 9. The
cross-bars d are connected to the outer ends of the inwardly turning bent levers KK
by means of screws e e and the inner ends of such levers K K are connected by
screws e¹ e to cross bars d' d¹ which through springs s¹ s¹ are connected to pillars c¹ c
fixed rigidly between two plates forming the sides of a fork L which is secured to
suspending rod M carrying the pendulum ball B. At an intermediate position in
the top of each of the levers K K within a groove is secured a bar d² like d shewn
in Figure 7 and this is connected to a pillar c² by a spring s². The pillars con
either side are secured in the pendent arms of a frame N secured together by a
suitable number of pillars, which frame is, through a central pillar, secured to the
lower end of the central rod G. The result is the same as in the previous case;
the intermediate pins of the levers connected to rod G of low expansibility sink less
under high temperature than the fulcrums connected to the rods H H of a higher
degree of expansibility the effect of which is to raise the inner ends of the levers
connected to the fork L and with the latter the ball B and thereby compensate for
temperature. At each of the three sets of joints in the two levers K the springs are
protected by causing the ends of the several bars d d¹ d² to extend loosely within
openings in the side plates of the several frames J, L, and N, so that while the
projecting ends are entirely free in the ordinary operation of the pendulum and the
whole weight hangs on the springs, any jars due to handling or transportation will be
transmitted by the ends of the bars directly to the frames themselves and the springs
thus protected from overstrain and injury. Any arrangement of levers common in
this class of pendulums may be employed instead of those shewn in the two types
herewith presented, so long as provision be made for the use of springs at the joints.
The proportions of the pendulums are to be so adjusted that when the clock is
running to mean time the centre of the ball (Figure 1) and the centre of the
springs t and s will be in the same horizontal line or nearly so and so that the centres
of all the springs in the full second type (Figure 12) will be in the same horizontal
line or nearly so.
In Figure 1, the amount of compensation for temperature can be adjusted by
sliding the plate i horizontally on the bearing provided for it and securing the same
with the screws shewn by pressure on washers covering the slotted holes. As the
rod a and its spring joint t are moved nearer and nearer the fulcrum C the motion
due to the difference in the expansion of the main plates A and the central rod a is
increased and the adjustment for temperature correspondingly increased. Adjust-
ments can be made with the construction shewn in Figures 12 and 15 by providing
similar means for shifting the points of connection of the bars d' d² in frame N and
levers K K or by changing the lengths of the lever arms in any customary way. It
will be evident that the general arrangement and many of the details of the
pendulums herein described are equally applicable to other pendulums and particu-
larly to those compensated with levers articulated with ordinary joints.
It is not necessary that the spring joints be actually made of a thin strip or lamina
secured in slits, as shewn in the drawings. It will answer in many cases to merely
mill from the sides of a circular or square rod, metal cavities of a semi-circular or
equivalent section, as shewn in Figures 19 and 20, leaving the metal or other material
quite thin for a shorter or longer distance so that all the flexure will take place at
that point. This system is particularly well adapted for the intermediate joints in
Figures 1 and 9 as thereby the spring may be worked out of a single rod fg. Nor
would there be any difficulty in applying such springs instead of the plates at the
fulcrum, in which case the rods of which they are formed would run through and be
secured in the pillar cand bar d.
It will be observed that springs of either form when constructed so that each
is practically integral with the parts to which it is attached, have an additional
advantage compared with ordinary joints in securing the parts together so as to
permit them to swing without slack motion. In an ordinary bearing, on account of
the necessary slackness of the pivot or journal in the pivot-hole, the first motion of
the pivot or journal is to slightly roll up the incline formed by the bottom of the hole

page_text: or bearing which rolling action necessarily produces a microscopic change of the
length of parts connected by such bearings sufficient to change the rate of a delicate
piece of apparatus like a pendulum but which does not take place with the mechanism
provided for herein.
The compensating bars operating the levers need not necessarily form part of the
rod supporting the main pendulum ball and need not be arranged in a substantially
vertical position, as shewn. With this form of joint, any arrangement may be
employed which has been used in the construction of other pendulums, for instance
there may be a large ball supported by a rod and not compensated and an arrangement
substantially similar to that shewn attached thereto to effect the compensation with
an auxiliary ball; or compound bars operating to effect the compensation through
levers may be merely attached either in a vertical horizontal or other position to the
main rod so long as by difference in expansion they secure compensation through
joints of the kind herein described.
The extension of the frames A above the points of suspension accomplishes the
double purpose of increasing the effective lengths of the compound compensating
rods and of bringing the adjusting screw k and weight table to such a point that
they may be conveniently operated from the top in gallery clocks or others where
the top is more accessible than the bottom. It will be observed that the upper part
of the frame A is slotted nearly opposite the flexing point of the suspending spring n
below the stud o and into this slot projects a pin d secured rigidly to the rear frame
of the clock. There is sufficient space between the sides of the slot and the pin to
prevent contact between them during the normal swing of the pendulum, but should
the clock receive any sudden shock or movement the sides of the slot will engage
with the pin thus bringing upon the pin any abnormal strain and preventing
distortion of the spring n and in case the spring should break the weight of the
pendulum will come upon the pin d without causing other injury. It will be
observed also, that, when a clock is regulated from the top of the pendulum and the
pendulum is started by hand from that point, the pin d³ will receive any unusual
shock transmitted to the suspending spring in such operation, though, as stated, in
the ordinary operation of the pendulum the frame will swing entirely clear of
the pin.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is;
1. A compensating pendulum provided with flexible joints, substantially as
described.
2. In a pendulum, the combination, with the ball, of compound rods a com-
pensating lever or levers and flexible strips or springs forming connections between
said parts.
3. In a pendulum, the combination, with the ball, of a compensating lever or
levers and of a compound rod having a portion of the length of one or both members
thereof reduced in thickness so as to be flexible substantially as and for the purposes
set forth.
4. In a pendulum the combination, with the ball, of a compensating lever or levers
and of bars or rods of different degrees of expansibility by heat constructed with
flexible or spring sections, substantially as described.
5. In combination with a flexible strip or spring employed as joint one or more
stop pieces arranged in connection with the frame so as to resist shocks and strains
at the joiut, after the spring is flexed a limited distance.
6. In a pendulum, the combination, with a joint provided with a flexible strip or
spring arranged to swing freely a limited distance, of secondary journals or bearings
adjusted in the frame so as to limit the motion of the spring.
7. A combined spring and articulated joint arranged and operating so that
limited movements cause only flexure of the spring or lamina and extreme movements
and shocks are received by the articulations or bearings, substantially as described.

page_text: 8. In a pendulum, the combination of frames A A pillar one or more springs
and a swinging cross-bar d provided with projections d engaging loosely with
openings in the frame, substantially as and for the purpose specified.
9. A pendulum ball provided near the centre with a lateral lug for the attach-
ment of one member of a compound rod through a joint and with suitable points
of attachment to receive, through a joint, another member of a compound rod thereby
forming a lever in the construction of the ball itself, substantially as specified.
10. In combination with a pendulum ball provided with lever compensation and
a compound bar operating the same, a guide tube h adjustable rod and adjusting
nut adapted to change the relative lengths of the two elements of the compound
bar to regulate the rate of the clock, substantially as set forth.
11. In a pendulum with compensating lever, an adjustable piece i with guide-
tube hand adjusting rod g arranged to shift directly or indirectly through other
parts one of the joints of the lever to or from the other joint so as to change the
leverage and thereby the rate of the compensation, substantially as and for the
purpose specified.
12. In a pendulum, the rods ƒ and g connected by a joint or flexible portion t in
combination with a shifting plate i, substantially as and for the purpose specified.
13. In a pendulum, the rods f and 9 connected by a joint or flexible portion t in
combination with tube h shifting plate i and adjusting screw j.
14. In combination, rods fand 9 connected by a joint or flexible portion t guide
tube and a pin and slot or equivalent to keep the spring or lamina in proper
direction, substantially as and for the purpose specified.
15. A compound pendulum rod in which the element of the greatest expansibility
by heat is formed in the shape of a frame with double plates secured together by
pillars as in clock construction provided at one point with means of attachment to the
arm of a compensating lever at another point with means of attachment to the
portion of the compound bar of least expansibility by heat and at another with
means of attachment to the supporting spring substantially as and for the purpose
specified.
16. In combination, double plates A A suitable pillars connecting the same as in
the construction of clock movements a piece also connecting the plates and
provided with means to receive a central rod a, a lug for connection directly or
indirectly with a suspending spring and means of attachment to a weighted lever.
17. A beat arm E provided with a slot or other means of attachment to the crutch
and with an accessible end or handle g¹ combined and arranged with the rod of a
pendulum in such manner that the said beat arm may be used to shift the relation
of the crutch to the pendulum rod and put the clock "in beat," substantially as
specified.
18. A beat arm E provided with means of attachment to a pendulum rod and
means for engaging with a suspending spring, substantially as specified.
19. A beat arm of a pendulum in combination with the rod and with a pendulum
ball hinged thereto, such beat arın being provided with a projection or offset for
limiting the motion of the ball, substantially as and for the purpose specified.
20. In combination, a pendulum ball B connected by joints to, and combined with,
a compound rod composed of the double plate frames A A connected by pillars as in
the construction of clock movements and made of a material of superior expansibility
by heat, a central rod a of inferior expansibility by heat, and a means of attachment
directly or indirectly with the point of suspension of the pendulum, substantially as
described.
21. In combination, a pendulum ball B connected by joints to, and combined
with, a compound rod composed of the frames A A of superior expansibility by heat,
a rod a of inferior expansibility by heat, an adjustable beat arm E, and means of
attachment to the point of suspension of the pendulum, substantially as and for the
purpose specified.
22. A compensating pendulum provided with compound bars acting to produce
compensation for temperature in which the two elements of the compound bar are

page_text: extended and connect together above the point of suspension of the pendulum, to
obtain greater effective length of the compensating bars.
23. A table or plate for receiving regulating weights and connected to the rod
of the pendulum above the point of suspension, substantially as and for the purpose
specified.
24. In a pendulum compensated by compound bars and a compensating lever and
provided with a combined ball and integral lever, the combination and connection of
the element of least expansibility by heat with the ball between the centre of the
same and the fulcrum of the integral lever, substantially as and for the purposes
specified.
25. The combination of a pendulum rod with its point of attachment to another
portion of the pendulum, through a ball or conical piece bearing in an opening
adapted to receive the same, substantially as and for the purposes specified.
.
.
1000
C. E. EMERY.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.