IMPROVE- IN GOVERNING APPARATUS
Year: 1862

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County
of Middlesex, Engineer and Patent Agent, for the Invention of "IMPROVE-
IN GOVERNING APPARATUS."-A communication from abroad by
Mr. Léon Foucault, of 29, Boulevart St. Martin, Paris.
Sealed the 12th June 1863, and dated the 30th December 1862.
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the 30th
December 1862.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN GOVERNING APPARATUS," to be as follows:-
This Invention relates to an improved isochronous centrifugal apparatus
for regulating the speed of machines with continuous motion.
The general arrangement is similar to Watt's governor, and is represented.at
Fig. 1 of the annexed Drawing. The vertical shaft S B receives motion in any
suitable manner, and turns on pivots carrying with it the arms SM, S M¹,
which are forked at the upper part, and suspended from a part mounted trans-,
versely to the axis. At the centres of each of these arms are jointed the
extremities of two equal sides completing the parallelogram, the two other
forked ends being jointed together at D, so as to converge similarly to the

page_text: two branches from the same point on the axis. The apex of the parallelogram
carries with it in its movements the hollow tube or coupling C, D, which slides
freely on the shaft, and terminates at the lower part by a projecting rim. The
connection between the various parts is represented at Figs. 2 and 3; Fig. 4
shows details of socket D.
I will now proceed to describe the parts producing the isochronism. If from
the point S, which is the centre of suspension of the arms, I take a length of
the shaft equal to two sides of the parallelogram, added to the part C, D, of
the movable socket, I determine a point B corresponding to the geometrical
limit of the motion of the lower edge of said socket. This point being
determined, I take at the same level a fixed point as the centre of motion of
a rod O, B. On the other hand I take a second fixed point at F, serving as
This lever is jointed at its
the centre of motion of an elbowed lever A, F.
upper end to a bar A, C, connected at its centre with a rod O, B. The
bar A, C, is of any suitable length, but which for greater clearness is repre-
sented in the Fig. as equal to S, M, and being jointed in the manner
described it results that, while its extremity A moves in a horizontal or nearly
horizontal direction, the other end C moves in a vertical direction. This
extremity C is furnished with a pin, see Fig. 2, which bears in its up-and-
down motion on the rim of the socket before mentioned. Lastly, to the lower
part of this elbowed lever is fixed a mass u, the weight and position of which
is regulated so as to exert a variable pressure on A by means of A, C, which
is determined according to the weight of the masses M, M, and the angle
formed by the horizontal bar A, C. These conditions being complied with,
the system will have a speed of revolution, which, instead of accelerating with
the expansion of the weights, as in Watt's governor, will maintain a uniform
speed, whatever may be the angles of arms SM, SM, to the vertical.
Whatever may be the length of the straight line A, C, the force applied at its
base perpendicular to the axis should equal the weight of the masses multi-
plied by the horizontal projection of said straight line in proportion to the
length of the arms. This pressure, see Fig. 1, is communicated by the
elbowed lever A, F, which transmits a variable portion of the weight fixed to
the oblique arm.
This apparatus, as above mentioned, may be applied to any machine in
order to regulate its power or resistance. It may also be applied as a regu
lator for clocks, or steam engines, or other motors, whatever may be their
nature. I may also apply it in combination with a train of wheels for com
municating motion to instruments for taking observations, as notwithstanding

page_text: the variable resistance and the irregularity of the motive power, it may be
used for obtaining motion exempt from any sensible variation in speed.
. Figs. 5, 6, 7, and 8 of the annexed Drawing represent this improved
governor as applied to clock mechanism, which may also serve as an example
for other similar applications on the same principle. In this apparatus the
variable resistance intended to overcome the excess of motive power, is fur-
nished by means of a fan V. of small dimensions, the orifices of which are
opened and closed by the action of the regulator itself.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by. the said William Clark in the Great Seal Patent Office on the 29th
June 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of December, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Clark, Her special licence, that I, the said William Clark,
my executors, administrators, and assigns, or such others as I, the said William
Clark, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN GOVERNING
APPARATUS," a communication to me from abroad by Mr. Léon Foucault,
of 29, Boulevart St. Martin, Paris, upon the condition (amongst others) that
I, the said William Clark, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and im-
mediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Clark, do hereby declare the
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement,

page_text: reference being had to the Sheet of Drawings hereunto annexed, and to the
letters and figures marked thereon (that is to say) :-
The object of this Invention is to provide science and the industrial arts
with a means of regulating with precision, the speed of machinery having con-
tinuous motion. I adopt generally the arrangement of Watt's governor, shown
at Fig. 1 of the Drawings annexed. The vertical shaft S, B, receives motion
in any suitable manner by means of gearing, belts, or otherwise, and turns
between pin bearings, and carries with it in its revolution the arms S M, S M',
which are forked at their upper part and suspended from a part set cross-
wise upon the axis. At the centre of each arm are jointed the ends of rods H,
of equal length, which complete the parallelogram, the other forked ends of
rods, Hare jointed together at D, so as to converge at same point upon the
axis of shaft S, B. The apex D of the parallelogram carries with it in its
motion the hollow tube or coupling C, D, sliding freely upon the shaft S, B,
and terminating at the lower part in a projecting rim d. The junction of
the various parts is represented in end view at Fig. 2; and partly in plan at
Fig. 6, while Fig. 7 represents a modified arrangement of same. I will
now enumerate the parts which contribute to produce isochronism. If
from the point S, Fig. 1, or centre of suspension of the arms of the governor,
I take a length of the shaft equal to two sides of the parallelogram, plus the
part C, D, of the movable socket, a point of the axis will be determined
corresponding to the geometrical limit of the course traversed by the lower
rim of said socket. This point being determined, a fixed point, B, is taken on
the same level as the centre of motion of the rod O, B. On the other hand,
a second fixed point is taken at F to form the centre of motion of a bent
lever A, F, . This lever is jointed at its upper end to a small bar or rod, A, C,
jointed at its centre to the rod O, B. The bar A, C, may be of any suitable
length, but it is supposed in the Figures to be equal to S, M, and from the
mode in which it is jointed it results that while its end A moves in a slightly
horizontal direction, the other end C moves in a slightly vertical direction.
Now this end Ċ is provided with a pin which bears on the under part of the
rim of the coupling. Lastly, at the lower part of the bent lever a mass
is fixed, the weight and position of which are determined so as to exert at A,
and through A, C, a pressure equal to P cos 4, P representing the united
weight of the two balls M and M', and the angle of bar A, C with the
horizontal A, B. These conditions being fulfilled the apparatus. will revolve
at a speed which instead of accelerating on the expansion of the balls, as in
Watt's governor, will, as herein-after described, be always maintained at the
same rate of speed for all variations or degrees of the angle a.
Like the

page_text: ordinary circular pendulum Watt's governor, having one point of suspension,
completes its whole revolution within a time expressed by
isochronism is realized. Now if g be multiplied by cos a, practically a portion
of the weight of the balls will be supported equal to
P (1 cos a) (1).
-
There now only remains to demonstrate that the mechanism before described
leads to such result. Taking AC=BS=SM=l, the angle B, A, C, being
indicated by , A B will become cos, still continuing to term P the total
weight of the balls M and M'. The sides of the parallelogram being all equal
half 1, the three points M, M', C, will remain in the same horizontal plane
whatever may be the position of the parts. Hence it results that power applied
at C, and acting in an upward direction, will be transmitted entirely to
the balls M, M¹. Supposing now that a power P equal to the weight of the
balls be applied on the straight line A C, so as to act in the direction of
Said line, the force or power neutralized by the resistance which it meets with
perpendicularly to the axis B S will furnish a vertical ascending component
equal to
Psin = P(1 cos a).
-
Such is the force which acts vertically on the point C, and which likewise
acting upon the weights M, M', fulfils the condition (1) required for realizing
isochronism. But in order that the straight line A C may be acted on by
a constant force P, and according to the variable direction A, C, the point A
must necessarily be acted on in the constant direction A, B, by the variable
force P cos, if the straight line A C be of a length U, different from it
would still be found that the force annlied at A should represent

page_text: lever A, F, μ, which transmits a variable part of the weight attached on the
oblique arm. I will now proceed to determine the proportions of these
parts. First, the arms of the governor are inclined at an angle of 45 degrees
which is practically the most favorable position for regulating the motion of
machinery, I then take a fixed point F, vertical to the point A, from which I
draw a straight line to B, which gives an angle w=A, F, B, determining the
inclination to be given to the oblique arm F, p. Lastly, and 1%, being the
length of the two arms F, A, and F, μ, of the bent lever, and a weight
and this component, transmitted to point A, becomes, on account of the inequa-
lity of the two arms,
Cos
+)
=P cos .
Finally, therefore, the weight μ, acting through the medium of the jointed
system imparts to the balls M and M³ an upward pressure which has exactly
the desired value (1) P 1 cos a, and fulfils the conditions of the problem.
However, this result is only perfectly obtained at the limit of the variations of
the angle w, and when the arc described from point a may be merged into the
horizontal line A, B, but if there be any error from this cause it is very trifling
and may be of inappreciable value.
Such are the data from which I have been enabled to produce with certainty
from a Watt's governor a perfectly isochronous apparatus which is readily
applicable for regulating the motion of all kinds of steam engines and other
machinery. In fact, when Watt's governor has once been modified as above
stated it constitutes a very exact indicator of the least variation of power
acting thereon, and in order that it may serve as the regulator of a machine
it suffices to connect the lever arm A, F, with parts repressive of the power or
resistance. It may be likewise employed for regulating clocks, steam engines,
or other motor, whatever may be its nature.
Apparatus according to this Invention is also applicable in connection with
spring wheelwork intended to impart motion to observatory instruments. It
will be understood that the object desired to be obtained is to generate a

page_text: movement which should be free of all perceptible variation in speed,
notwithstanding the accidental. and variable resistance offered to the motive'
power and the variations of the motive power itself.
I will now proceed to describe somewhat minutely the apparatus whereby
this difficult problem is solved, which will serve, with some slight variation, as
a standard of the various applications which may afterwards be worked out on
the same principle.
Description of the wheel mechanism with continuous motion and constant
speed for astronomical and chronographic operations.-This mechanism .or
wheelwork is intended to work in the open air, while the motive power is
variable, as also the work, and the machine must, in opposition to these varia-
tions, preserve a uniform motion; for this purpose it is necessary to apply an
auxiliary resistance equally variable, and always ready to take up the excess of
motive power.
In this improved apparatus such variable resistance is afforded by a rotary
fan apparatus V, Fig. 5, of small size, the orifices of which are opened and
closed by the action of the governor, all parts being so disposed that this action
may be fulfilled without causing any reaction which might disturb the
isochronism of the regulating apparatus. There is also in the arrangement of
the latter a peculiarity of construction which has for effect to eliminate the
action of passive resistances, and restore thereto the conditions of a free body.
This last improvement will be treated under a particular head, as it
constitutes an important point, whereby the new governor acquires a high
degree of precision. A powerful spring motor enclosed in a barrel B, Fig. 3,
imparts by a system of gearing the motion to the governor; the wheelwork also
extends beyond, so as to turn the fan wheel at a high speed (from 30 to 35
revolutions a second); this fan wheel is enclosed in a cylindrical case V, Figs.
& 5, which is furnished with twelve equidistant apertures alternating with solid
parts of same size, and enclosed in an external jacket suspended from a central
fulcrum pin, which jacket or cover has also the same number of apertures as
the cylindrical case. It suffices, therefore, for said jacket to turn one-twenty-
fourth of a revolution for all the orifices to be opened or closed at once, and
for the circulation of air to be established or intercepted. A light rod T, fitted
near the central point, Fig. 3, establishes the communication with the vertical
branch or arm of the bent lever connected with the governor, whereby the
changes of position of the balls, consequent on the least variations of the
motive power, are immediately attended with a change corresponding to the
resistance. As long as the orifices of the ventilator are neither completely
opened nor closed, the resistance which it opposes to the motion remains

page_text: completely dependent upon the evolutions of the governor, and as the latter is
isochronous, the machine and all the working parts must necessarily partake
of this uniform motion.
In this description I have hitherto made no reference to the passive resistances
inherent in the mode of construction of Watt's governor, and also of such as
are introduced with the parts tending to render it isochronous; these resistances
have, however, an influence which should not be overlooked; and which pre-
dominate in proportion as the other causes of error are overcome. If, therefore,
they are not prevented, the only benefit to be derived from the new construction
will be to ensure a medium speed, which would constantly vary more or less
concurrently with the variations corresponding to the influence of this very-
resistance. I have however found a means of obviating these defects, which.
consists in giving a peculiar form to the surface, by which relation is established
between the governor and the machinery from which it derives its isochronism.
This surface, which forms a flanch terminating the lower part of the socket
jointed to the parallelogram, is undulated at two points, as seen at Fig. 2 bis, so
as to pass twice alternately above and below the plane, which should coincide
with the uniform surface of revolution. This surface on sliding above the pin C,
Fig. 2, which bears upon it, imparts an alternating motion to all parts of the appa-
ratus, by means of which each of the parts of which it is composed, in oscillating
round its mean position will accurately transmit the smallest force which actuates.
it. In order to render it effective the undulations should not be too deep. In
the wheelwork described there is not above nds of an inch difference.of
level between the hollows and the projecting parts. The result is perfect, and,
notwithstanding the variations of the spring power and of the work, the wheel-
work will furnish from beginning to end a speed which will not vary 5000 part.
This Invention may be applied on all occasions where Watt's governor is
used, as, in addition thereto, this arrangement works with a precision never
heretofore attained. I wish it to be likewise understood that I claim the
same in all the applications that may be made thereof in clockwork, telegraphy,
and chronography.
Having described the nature of this Invention, and the manner of performing
the same, I may remark that the peculiar features of this Invention are the
mode of suspension of the branches of the governor, which are jointed at the
same point upon the axis at the lower ends of a parallelogram, as also the com-
bination of the bent lever of the oblique bar and the rod, also jointed to a fixed
point on the axis, and that what I claim as the Invention, and desire to secure
by the herein-before in part recited Letters Patent, is,―
First, the improved governor, which is rendered isochronous on the conditions.

page_text: and principles herein-before described and represented, to be applied for any
purpose desired.
Secondly, I claim the arrangement of isochronous governors, as also the
various modifications of the accessory parts, as described.
Thirdly, I claim the application of a practical means of eliminating the
influence of passive resistances, which consists in the employment of an
undulated surface intended to produce an oscillating motion in all parts of the
mechanism in connection with the governors.
Fourthly, I claim the description of fan, serving in small apparatus as a
variable resisting agent without producing any reaction upon the governor.
Fifthly, I claim the application of a spring and train mechanism or wheel-
work in connection with the isochronous governors and fan, as described.
In witness whereof, I, the said William Clark, have hereunto set my
hand and seal, this Twenty-seventh day of June, in the year of our Lord
One thousand eight hundred and sixty-three.
Witness,
W. G. E. SWINNOCK,
53, Chancery Lane,
London.
W. CLARK. (L.S.)