IMPROVED AUTOMATIC COMPENSATING MECHANISM FOR THE GOVERNORS OF MOTIVE POWER ENGINES
Year: 1871

page_text: ¡ETTERS PATENT to William Robert Lake, of the Firm of Haseltine,
Lake, & Co., Patent Agents, Southampton Buildings, London, for
the Invention of "IMPROVED AUTOMATIC COMPENSATING MECHANISM FOR
THE GOVERNORS OF MOTIVE POWER ENGINES."-A communication from
abroad by Gustave Denis, of No. 13, Boulevard St. Martin, Paris,
France, Manufacturer.
Sealed the 12th December 1871, and dated the 20th July 1871.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition,
on the 20th July 1871.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "IMPROVED AUTOMATIC COMPENSATING
MECHANISM FOR THE GOVERNORS OF MOTIVE POWER ENGINES," a communication,
to be as follows:-
The governors ordinarily employed for regulating steam and other
engines have usually the disadvantage of being connected unadjustably
to the throttle valve or the expansion gear, so that they themselves

page_text: require regulating by the engine driver every time the conditions of
pressure or resistance are changed to any considerable extent. It has
been sought in many ways to obviate this inconvenience, amongst others
by causing the pendulum balls to describe a parabolic curve or arcs of a
circle approximating to a parabola, but although great advantages have
been thereby realized there is not, to my knowledge, in practical use a
governor which has not itself to be regulated from time to time by
the hand of the engine driver. I have therefore sought to discover a
simple and certain means for automatically regulating governors while
preserving all the freedom and "sensitiveness" which are indispensable
and the necessity for which has hitherto caused a preference to exist
for the centrifugal governor over all others in spite of its defects.
To arrive at the desired result it has been necessary to analyse the
circumstances which arise every time the engine departing from its
normal speed has to be brought back thereto by the governor. Let us
take, for example, an engine working at 25 horses' power; at a given
moment the resistance diminished by the disconnection of one or a
number of machines driven by the said engine is reduced to 15 horses'
power. The speed of the engine is immediately accelerated and the
governor closes the throttle valve or increases the expansion, as the
case may be, but the engine having to work with only a force of
15 horses' power instead of 25, it follows that the lever of the throttle
valve or of the expansion valve must occupy a different position to that
which it occupied for the 25 horses' power. Therefore, if the said lever
is connected without a capability of adjustment to the governor, the
position of the latter must also be different to that which it first
occupied, a state of things indicating positively a change in the speed
of the engine. The effect is the same if the resistance remains
unchanged and a variation occurs in the power, that is to say, in the
This inconvenience it will be seen arises from
pressure of the steam.
the unadjustability of the connexions between the governor and the
throttle or expansion valve, and to obviate the same it will only be
necessary to vary one or more of the parts of such connection in such
manner as to exactly compensate for the effect produced by the
variations in the power or the resistance, always observing the indis
pensable condition of preserving in the governor its freedom and
sensitiveness. The realisation of these two conditions, namely, the
adjustability of the aforesaid connections and the preservation of the

page_text: this Invention.
Let us take as an example the arrangement illustrated in the diagram,
Figure A, to which simple form nearly all the arrangements used may
be reduced; in this diagram the lever Lacts on the throttle valve or
expansion valve, and it will be observed that the compensation may be
effected by varying in the desired proportion either the distance a or
the distance b. I may therefore adopt two arrangements based on the
same principle, one of which is best adapted for beam engines and the
other for horizontal engines, although either may be used for any kind
of engine.
I call the first a differential motion automatic compensator. It has
for its object the variation of the distance a on the aforesaid diagram.
The second arrangement I call an inverse motion automatic com-
pensator, its object being to vary the distance b on the said diagram.
The first arrangement is illustrated in Figures 1, 2, and 3, of which
Figure 1 represents the ordinary pendulum governor. The collar D,
to which are connected the two rods B, B¹, is provided with two rods &
that instead of being connected unadjustably in the ordinary manner
to the throat which receives the fork for operating the throttle valve
are connected to a small metal collar C in two pieces. Figure 2 is a
vertical section of the compensator; Figure 3 is a horizontal section of
the same, on the line z, z, Figure 2. The collar C embraces a throat
formed in a brass nut carried by the screw F, also preferably formed of
brass. This screw, which is fitted to slide vertically upon the shaft A
with the other parts of the arrangement), is caused by a key fixed in
the shaft to follow the rotation of the pendulums. It has at the upper
end a throat G for the reception of the fork K. It will be understood
that so long as the screw and its nut turn around the shaft A with the
same velocity the action is the same as that of an ordinary governor,
and the reciprocating movement of the throat G will be identically
the same as those of the collar D, Figure 1, which is influenced directly
by the action of the balls; but if the speed of the nut becomes at any
given moment greater or less than that of the screw the said screw
will rise or descend, the collar D being allowed at the same time to
occupy one invariable position upon the shaft A.
I will now describe the part of the apparatus intended to vary the
speed of the nut within the required limits. The shaft A just below

page_text: the joint T of the two pendulum arms carries a metal piece composed
of a nave keyed upon the shaft and a ring connected by arms to the
said nave. Upon this ring rest two gear wheels R', R¹¹, the wheel R¹
having 102 teeth and the wheel R 106 teeth. A small shaft I, whose
support may be fixed upon any convenient part of the engine, is provided 5
with two pinions P1, P", whereby it governs the said wheels, the pinion P¹
having 26 teeth and the pinion P" 24 teeth. The shaft I is controlled
by the shaft A through the medium of the wheel R with 104 teeth
which operates the pinion P with 25 teeth. The metal ring of the
piece M.carries three screws H whose ends enter a circular groove o so ]
as to prevent the vertical displacement of the wheel R". For a like
purpose three small steel or iron plates fixed by screws
wheel R" enter the circular groove N and hold the wheel R¹.
upon the
It will be seen from the above description that if the speed of the
shaft A should be 50 revolutions per minute the wheel R" will make 1
= 47.09, and the wheel R' will make
104 x 24
in the same time 50 × 106 × 25
104
50 X * 26=53-02.
102 × 25
Figure 2, in which the pendulums are supposed to be in a medium
position or in the position they occupy when the engine is running at its
normal velocity, shows that the flange of the nut E is then precisely at 1
the centre of the height of the cylinder formed by the two wheels R¹, R",
which surround it. Each of these two wheels has at its inner circum-
ference a tooth or number of teeth (according to the speed of the
pendulums) which do not occupy the entire height of the wheels and
leave in the middle of the cylinder a vacant space equal to the thickness
of the brass nut. The latter has a tooth Q which occupies the entire
height of the flange. So long as the engine maintains its normal velocity
the nut will retain its medium position and the tooth Q will turn
without coming in contact with either of the teeth Q', Q", and this nut
moved by the collar C and by the screw F will turn at the same speed
as the latter, but as soon as the speed diminishes the balls drop and
depress the screw and nut, the forked lever will be equally moved and
will open more fully the throttle valve; at the same time the flange of
the nut no longer occupying the medium position its tooth will come in
contact with that of the wheel R", and the nut instead of making 50
revolutions with the screw F will only make 47.09 with the wheel R".
The result will be that in the space of one minute, for example, the
nut will have made 2.91 revolutions less than the screw, and that

page_text: supposing the position of the balls has not been changed, the throat
receiving the fork will descend a space equal to 2.91 times the pitch of
the screw.
This effect will continue till the throttle valve is sufficiently
open to re-establish the normal velocity, the balls then returning to
their medium position the tooth of the disc no longer comes in contact
with that of the wheel R, and the nut will be moved at the same speed
as the screw. The same effect is produced in an inverse direction when
the speed becomes too great. Then the tooth of the wheel R' meets
that of the disc and moves it at a velocity of 53.02 revolutions while
the screw makes one 50. This effect ceases as soon as the throttle
valve is closed sufficiently to re-establish the normal velocity, the balls
and the disc then regaining their medium position. The length of the
screw F and the position of the wheel R are so calculated that the travel
of the screw being limited above by the wheel R and below by the
shoulder of the joint T, the throttle valve will be completely closed
when the upper part of the screw comes in contact with the boss of the
wheel R, and fully opened when the screw rests upon the shoulder of
the said joint.
Figure 1 represents the governor at rest, it being supposed that the
throttle valve is fully opened; Figure 2 represents the apparatus as it is
when the engine is running at its normal velocity.
The apparatus is so constructed that if under peculiar circumstances
the normal speed of the engine is prolonged when the throttle valve is.
at the end of its motion the screw E moved by one of the wheels R', R",
and turning upon the screw F can lower or raise the balls till they are
in the vacant space between the teeth Q' and Q". This will happen,
for example, when the engine is stopped, the balls then are. suspended
as indicated in Figure 1, and their weight is borne by the shoulder of
the joint T through the medium of the screw F and nut E which then
support the governor entirely.
In the preceding description it is assumed that the governor controls
a throttle valve or admission valve, but no change in the compensating
mechanism would be needed to adapt it to expansion gear.
The apparatus above described is applicable to an engine in which
the fork lever for transmitting motion to the throttle valve is placed
above the governor. To apply it to engines where this lever would be
below the governor only a very slight modification will be required

page_text: The compensating mechanism represented in Figure 2 would then be
reversed with the exception of the wheels R', R", which must always
be placed in the same position. The piece M must be replaced by a
support bolted upon one of the fixed parts of the machine and carrying
a ring similar to that of the piece M for receiving the two wheels R¹
and R".
In the modification of my Invention which I call the automatic
inverse motion compensator, the differential arrangement is replaced by
two wheels turning in opposite directions as indicated in Figures 4, 5,
and 6, of which Figure 4 is a vertical elevation of the said compensator;
Figure 5 is a vertical section of the same on the line y, y, Figure 4;
Figure 6 is a horizontal section on the line z, z, Figure 5.
The rod A is screwed at its lower extremity to receive thereon a
nut E and is connected by two links to the lever of the throttle valve
or expansion gear. Its upper extremity is fitted to turn freely in a
socket which oscillates in a small fork jointed to one extremity of the
lever which transmits the oscillations of the governor. The said rod
therefore connects the throttle valve or expansion gear with the governor,
and by varying the distance between the nut and the jointed fork the
automatic compensation will be obtained. To produce this variation I
give the said rod a rotating movement, which according to its direction
will move the nut in or out upon the said rod. For this purpose I pass
the rod A through the centre of the two bevil wheels R, R'. These
two wheels are carried by small iron rings C, C¹, bolted upon the
bracket S, the said wheels are driven by the pinion P keyed on the
shaft F which receives motion from any convenient rotating part of
the engine. The bracket S is secured upon one of the fixed parts of the
engine or upon a shelf T secured thereto. The wheels R, R', are both
driven by the pinion P, and consequently turn in opposite directions,
each wheel carries an interior cog or tooth L, L, made of steel and
dovetailed inside its boss. Upon the rod A is a small steel ring secured
by a pin and formed with a tooth. The height of this ring is slightly
less than the vacant space between the wheels R, R³, and it occupies
a position corresponding with this space when the governor is in its
normal position. When the governor changes its position the ring B
engages in the boss of one of these wheels which then moves the rod A,
the nut E being consequently raised or lowered in such manner as to
actuate the throttle valve in the same direction as the governor. For

page_text: guiding the rod A. the wheel R¹ carries at its lower part a brass plate
perforated with a hole slightly larger in diameter than the rod.
The following are the necessary indications for determining the
direction of the thread of the screw and of the rotation of the wheels.
If the governor is so arranged as to raise the rod A when the engine
is not moving quickly enough the wheel R must turn in such a direction
that the rod A screws itself into the nut E and is thus practically
shortened. In the contrary case the action is reversed. It will be
necessary to arrange two stops for limiting the travel of the lever I,
the aforesaid brass plate may serve for the upper stop.
In some cases the throttle valve lever is replaced by a worm wheel
gearing with a screw carried by the rod A.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 12th January 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of July, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Robert Lake, Her special licence
that I, the said William Robert Lake, my executors, administrators,
and assigns, or such others as I, the said William Robert. Lake, 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 “IMPROVED
AUTOMATIC COMPENSATING MECHANISM FOR THE GOVERNORS OF MOTIVE POWER
ENGINES," a communication to me from abroad by Gustave Denis, of
No. 13, Boulevard St. Martin, Paris, France, Manufacturer, upon
the condition (amongst others) that I, the said William Robert Lake,
my exccutors or administrators, by an instrument in writing under my,

page_text: 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Robert Lake, 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, reference being had to the accompanying
Drawing forming a part of this Specification.
A
The governors ordinarily employed for regulating steam and other
engines have usually the disadvantage of being connected unadjustably
to the throttle valve or the expansion gear, so that they themselves
require regulating by the engine driver every time the conditions of
pressure or resistance are changed to any considerable extent. It has
been sought in many ways to obviate this inconvenience, such as by
causing the pendulum balls to describe a parabolic curve or arcs of a
circle approximating to a parabola, but although great advantages have
been thereby realized there is not, to my knowledge, in practical use a
governor which has not itself to be regulated from time to time by the
hand of the engine driver. I have therefore sought to discover a simple
and certain means for automatically regulating governors, while pre-
serving all the freedom and instantaneous action which are indispensable,
and the necessity for which has hitherto caused a preference to exist for
the centrifugal governor over all others in spite of its defects.
To arrive at the desired result it has been necessary to analyse the cir-
cumstances which arise every time the engine departing from its normal
speed has to be brought back thereto by the governor. Let us take, for
example, an engine working at 25 horses power at a given moment, the
resistance diminished by the disconnection of one or a number of
machines driven by the said engine is reduced to 15 horses power.
The
speed of the engine is immediately accelerated and the governor closes
the throttle valve or increases the expansion as the case may be, but the
engine having to work with only a force of 15 horses power instead of
25 it follows that the lever of the throttle valve or of the expansion
valve must occupy a different position to that which it occupied for the
25 horses power.
Therefore if the said lever is connected without a
capability of adjustment to the governor, the position of the latter must

page_text: also be different to that which it first occupied. This indicates
positively a change in the speed of the engine. The effect is the same
if the resistance remains unchanged, and a variation occurs in the
power, that is to say, in the pressure of the steam. This inconvenience,
it will be seen, arises from the unadjustability of the connections
between the governor and the throttle or expansion valve, and to
obviate the same it will only be necessary to vary one or more of the
parts of such connections in such manner as to exactly compensate for
the effect produced by the variations in the power or the resistance,
always observing the indispensable condition of preserving in the
governor its freedom and instantaniety of action. The realization of
these two conditions, namely, the adjustability of the aforesaid con-
nection and the preservation of the freedom and instantaneous action of
the governor is the characteristic feature of this Invention.
Let us take as an example the arrangement illustrated in the diagram,
Figure A, to which simple form nearly all the arrangements used may
be reduced. In this diagram the lever L acts on the throttle valve or
expansion valve.
It will be observed that the compensation may be effected by varying
in the desired proportion either the distance a or the distance b. I may
therefore adopt two arrangements based on the same principle, one of
which is best adapted for beam engines and the other for horizontal
engines, although either may be used for any kind of engine. I call the
first a differential motion automatic compensator. It has for its object
the variation of the distance a on the aforesaid diagram, and is par-
ticularly applicable to beam engines. The second arrangement I call
an inverse motion automatic compensator, its object being to vary the
distance b on the said diagram, and it is particularly applicable to
horizontal engines.
The first arrangement is illustrated in Figures 1, 2, and 3, of which
Figure 1 represents the ordinary pendulum governor. The collar D to
which are connected the two links B, B', is provided with two rods S
that instead of being connected unadjustably in the ordinary manner to
the throat which receives the fork for operating the throttle valve are
connected to a small metal collar C in two pieces. Two small pins x, x,
screwed at each side into the boss of the piece M, and projecting about
five-eighths of an inch serve to guide the rods S, S', and keep them

page_text: in a vertical line; Figure 2 is a vertical section of the compensator;
Figure 3 is a horizontal section of the same on the line y, y, Figure 2.
The collar C embraces a throat formed in a brass nut E carried by the
screw F, also preferably formed of brass. This screw which is fitted to
slide vertically upon the shaft A is (with the other parts of the arrange-
ment) caused by a key fixed in the shaft to follow the rotation of the
pendulums. It has at the upper end a throat G for the reception of the
fork K.
It will be understood that so long as the screw and its nut turn with
the same velocity the action is the same as that of an ordinary governor,
and the reciprocating movements of the throat G will be identically the
same as those of the collar D, Figure 1, which is influenced directly by
the action of the balls; but if the speed of the nut becomes at any given
moment greater or less than that of the screw, the said screw will rise
or descend, the collar D being allowed at the same time to occupy one
invariable position upon the shaft A.
I will now describe the part of the apparatus intended to vary the
speed of the nut within the required limits.
The shaft A, just below the joint T of the two pendulum arms, carries
a metal piece composed of a nave keyed upon the shaft, and a ring
connected by four arms to the said nave. Upon this ring rest two gear
wheels R', R", the wheel R¹ having 102 teeth and the wheel R" 106
teeth. A small shaft I, whose support may be fixed upon any con-
venient part of the engine, is provided with two pinions P¹, P", whereby
it governs the said wheels, the pinion P¹ having 26 teeth and the
pinion P 24 teeth. The shaft I is controlled by the shaft A through
the medium of the wheel R with 104 teeth which operates the pinion P
with 25 teeth. The cast-iron ring of the piece M carries three screws H
whose ends enter a circular groove O, so as to prevent the vertical
displacement of the wheel R". For a like purpose three small steel
or iron plates fixed by screws upon the wheel R" enter the circular
groove N, and hold the wheel R¹.
L
It will be seen from the above description that if the speed of the
shaft A should be 50 revolutions per minute, the wheel R" will make
in the same time 50 ×
104 × 24
ነሰር
= 47.09, and the wheel R' will make

page_text: Figure 2, in which the pendulums are supposed to be in a medium
position or in the position they occupy when the engine is running at
its normal velocity, shows that the flange or disc of the nut E is then
precisely at the centre of the height of the cylinder formed by the two
wheels R, R", which surround it. Each of these two wheels has at its
inner circumference a tooth or number of teeth (according to the speed
of the pendulums) which do not occupy the entire height of the wheels,
and leave in the middle of the cylinder a vacant space equal to the
thickness of the flange of the brass nut. The latter has a tooth Q which
occupies the entire height of the flange.
So long as the engine maintains its normal velocity the nut will
retain its medium position, and the tooth Q will turn without coming
in contact with either of the teeth Q, Q", and this nut moved by the
collar C and by the screw F will turn at the same speed as the latter ;
but as soon as the speed diminishes the balls drop and depress the screw
and nut; the forked lever will be equally moved, and will open more
fully the throttle valve; at the same time as the flange of the nut
no longer occupies the medium position its tooth will come in contact
with that of the wheel R", and the nut instead of making 50 revolutions
with the screw F will only make 47.09 with the wheel R". The result
will be that in the space of one minute, for example, the nut will have
made 2.91 revolutions less than the screw, and that supposing the
position of the balls has not been changed the throat receiving the
fork will descend a space equal to 2.91 times the pitch of the screw.
This effect will continue till the throttle valve is sufficiently open to
re-establish the normal velocity; the balls then returning to their
medium position the tooth of the disc no longer comes in contact with
that of the wheel R", and the nut will be moved at the same speed as
the screw.
The same effect is produced in an inverse direction when the speed
becomes too great. Then the tooth of the wheel R' meets that of the
disc or flange, and moves it at a velocity of 53-02 revolutions, while the
screw makes only 50. This effect ceases as soon as the throttle valve is
closed sufficiently to re-establish the normal velocity, the balls and the
dise then regaining their medium position.
The length of the screw F and the position of the wheel R are so
calculated that this travel of the screw being limited above by the
wheel R and below by the shoulder of the joint T, the throttle valve will

page_text: be completely closed when the upper part of the screw comes in contact.
with the boss of the wheel R, and fully opened when the screw rests
upon the shoulder of the said joint.
For the sake of clearness of illustration the screw F is shewn too
long in Figure 1, and (contrary to the Drawing) when the lower
extremity of the screw rests on the shoulder T, the throat G partly
disappears within the wheel R¹.
Figure 1 represents the governor at rest, it being supposed that the
throttle valve is fully opened.
Figure 2 represents the apparatus as it is when the engine is running
at its normal velocity.
The apparatus is so constructed that if under peculiar circumstances
the abnormal or irregular speed of the engine is prolonged when the
throttle valve is at the end of its motion, the nut E moved by one of
the wheels R¹, R", and turning upon the screw F can lower or raise the
balls till they are in the vacant space between the teeth Q¹ and Q".
This will happen, for example, when the engine is stopped; the balls
then are suspended as indicated in Figure 1, and their weight is borne
by the shoulder at the joint T through the medium of the screw F and
nut E which then support the governor entirely.
In the preceding description it is assumed that the governor controls
a throttle valve or admission valve, but no change in the compensating
mechanism would be needed to adapt it to expansion gear.
The apparatus above described is applicable to an engine in which
the fork lever for transmitting the motion to the throttle valve is placed
above the governor. To apply it to engines where this lever will be
below the governor, only a very slight modification will be required.
The compensating mechanism represented in Figure 2 would then be
reversed, with the exception of the wheels R¹, R", which must always
be placed in the same position. The piece N must be replaced by:
a support bolted upon one of the fixed parts of the machine, and
carrying a ring similar to that of the piece M for receiving the two
wheels R¹ and R". In the governor represented in Figures 1 and 2
the pendulums turn in the direction of this arrow
and by reason
of the arrangement of the wheels R', R", the thread of the screw is a
left-handed.
In the modification of my Invention, which I call the automatic
inverse motion compensator, the differential arrangement is replaced by

page_text: The
two wheels turning in opposite directions, as indicated in Figures 4, 5,
and 6, of which Figure 4 is a vertical elevation of the said compensator.
Figure 5 is a vertical section of the same on the line y, y, Figure 4;
Figure 6 is a horizontal section on the line z, z, Figure 5.
rod A is screwed at its lower extremity to receive thereon a nut E,
and is connected by two links to the lover of the throttle valve or.
expansion gear. Its upper extremity is fitted to turn freely in a socket
oscillating in a small fork, jointed to one extremity of the lever which
transmits the oscillations of the governor; the said rod therefore
connects the throttle valve or expansion gear with the governor, by
varying the distance between the nut and the jointed fork the automatic.
compensation will be obtained; and for varying the same I give the
said rod a rotating movement, which according to its direction will move
the nut in or out upon the said rod. To produce this movement I pass
the rod A through the centre of the two bevil wheels R, R¹. These
two wheels are carried by small iron rings C, C', bolted upon the
bracket S. The said wheels are driven by the pinion P keyed on
the shaft F, which receive motion through wheel gearing or bands
or belts from any convenient rotating part of the engine. The bracket S.
is secured upon one of the fixed parts of the engine, or upon a shelf T
secured thereto. In some instances the bracket S may be fixed on
the floor. The wheels R, R', are both driven by the pinion P, and
consequently turn in opposite directions; each wheel carries an interior
cog or tooth L, L', made of steel dovetailed inside its boss. Upon the
rod A. is a small steel ring secured by a pin and formed with a tooth.
The height of this ring is slightly less than the vacant space between
the wheels R, R¹, and it occupies a position corresponding with this
space when the governor is in its normal position. When the governor
changes its position the ring B engages in the boss of one of these
wheels which then moves the rod A, the nut E being consequently
raised or lowered in such manner as to actuate the throttle valve in the
same direction as the governor. For guiding the rod A the wheel R¹
carries at its lower part a brass plate D perforated with a hole slightly
larger in diameter than the rod.
The following are the necessary indications for determining the
direction of the thread of the screw, and of the rotation of the wheels.
If the governor is arranged to raise the rod A when the engine is not
moving quickly enough, the wheel R must turn in such a direction that

page_text: •
the rou A screws itself into the nut E, and is thus practically shortened.
In the contrary case the action is reversed. It will be necessary to
arrange two stops for limiting the travel of the lever I; the aforesaid
brass plate may serve for the upper stop.
In the Drawing the rod A is supposed to be prolonged above the
arrangement of toothed wheels; this is necessary to enable the above-
described guiding devices to operate properly, otherwise these guiding
devices would have to be modified. The two wheels might occupy any
position beside that indicated in the Drawing; thus the rod A is
sometimes prolonged below the lever of the throttle valve or expansion
valve; this lever is then replaced by an endless screw or worm wheel,
geared with a square-threaded screw carried by the rod A; then the
compensating arrangement may be placed at any desired point on
the rod, and in this case it will be often advantageous to fix it on the
engine room floor. Experience has shewn that the two wheels R, R¹,
should form by their hollow bosses a cylinder having no other solution
of continuity than the play necessary to prevent the touching of the
two wheels; only the interior cogs or teeth L and L' should be cut in
such a manner that there will be at the centre of the height of the said
cylinder a free space equal to the thickness of the ring B. Furthermore
this ring B should carry four teeth instead of one, so as to form a
cross bar with four wings whose diameter will be a little less than the
internal diameter of the cylinder formed by the two wheels. In many
cases this cross bar will be sufficient for guiding the rod A, and
keeping it in the axis of the two wheels R, R¹.
By means of the automatic compensating mechanism, either with the
differential or the inverse movement, I can, at any time, convert an
ordinary governor into an excellent regulating governor, and thereby
solve the problem, which has so long occupied the attention of inventors.
Consequently the advantage possessed by this mechanism over those
governors called isochronous will be readily seen if it is remembered that
always when an isochronous governor is constructed it is soon manifest
that the apparatus has lost all stability, and as this quality is
indispensable for properly governing an engine, it becomes necessary,
by means of springs or counterweights to destroy, more or less, the
isochronism of the said governor to give it stability. Absolute
isochronism and stability are incompatible; so in practice it has only
hitherto been customary to use ordinary governors, and not "regula-

page_text: tors" in the strict sense of the word. The automatic compensator is
the only mechanism which permits the obtention of mathematical
regularity, while retaining in the regulating apparatus the stability,
freedom, and instantaniety of action.
Having thus fully described the said Invention as communicated to
me by my foreign correspondent, and the manner in which the same
is to be performed, I claim the above-described arrangement of the
automatic compensator for motive-power engines, having as its principle
the union of the two following conditions realized simultaneously,
namely,
-
First. The variability and consequently the automatic regulation of
the contrivances connecting the governor to the throttle valve or the
expansion gear.
And, Second. The preservation of the freedom, and the instantaniety
of action of the governor.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this Twelfth day of January, in
the year of our Lord One thousand eight hundred and seventy-
two.
Witness,
E. C. JACKSON.
WM. ROBT. LAKE. (L.S.)