IMPROVEMENTS . IN CENTRIFUGAL GOVERNORS AND MEANS OF GOVERNING STEAM AND OTHER ENGINES
Year: 1867

page_text: LETTERS PATENT to Henry Davey and David Davy, both of Sheffield,
in the County of York, Engineers, for the Invention of "IMPROVEMENTS
. IN CENTRIFUGAL GOVERNORS AND MEANS OF GOVERNING STEAM AND OTHER
ENGINES."
Sealed the 17th December 1867, and dated the 3rd July 1867.
PROVISIONAL SPECIFICATION left by the said Henry Davey and David
Davy at the Office of the Commissioners of Patents, with their Petition,
on the 3rd July 1867.
We, HENRY DAVEY and DAVID DAVY, both of Sheffield, in the County of
York, Engineers, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN CENTRIFUGAL GOVERNORS AND MEANS OF GOVERNING STEAM AND
OTHER ENGINES," to be as follows:--
This Invention has for its object the more perfect governing the speed of
steam and other engines, and consists, first, in a means by which the balls or
pendulums of the centrifugal governor are made to move in a true or approxi-
mate parabolic curve when moving from one plane of rotation to another; also
in a means by which the pendulums are made to give motion to the valve,
valves, or gear, so that when moving from one plane of rotation to another
shall in moving through equal lengths of the curve which they describe pro-
duce truly or approximately equal results; and also in the mode by which the
throttle or governing valve is attached to the gear of the governor, so that
when the balls are at rest, or in their lowest plane of rotation, the throttle or
governing valve is closed: The spindle around which the pendulums revolve
is according to this Invention provided with a curved horn or horns. The arm

page_text: by which the weight is suspended forming the pendulum is made of a flexible
material, by preference steel, and is secured to the horn at or near the
extremity in such a manner that the arm forms a tangent to the curve of the
horn from which it is suspended, which curve can be made of such a form that
the pendulum in moving from one plane of rotation to another is caused to move
in a true or approximate parabolic curve. The pendulum in moving from one
plane of rotation to another move between forked arms (or on arms not forked)
of a piece of metal sliding on the spindle of the governor. The arms last named
are provided with curved slots, in which pins which are attached to the balls
or weights of the pendulums are made to slide, or the arms may be solid, but
the slots or arms are so curved that equal lengths of the curve described by
the pendulums produce true or approximately equal results with the gear
acted on. The pendulums may be employed though with any other convenient
arrangement in the place of that last described. The throttle or governing
valve may be made of any convenient form provided with a port or ports, but
according to this Invention it is so connected to the pundulums that when in
their lowest position, or nearest to the centre of rotation, the port.shall be closed
or nearly so, as desired, to obtain which the slot in the arms or between which
the weights move may be made parallel to the axis of rotation at the extremity
nearest the centre of rotation. In place of the lever ordinarily employed for
throttle valves we place on the spindle a quadrent provided with notches of
any convenient form on its edge, and on one side of the quadrent we provide
an ordinary lever moving loose on the spindle. On the lever we place two
catches kept down on the quadrent by means of springs, and so, arranged that
on moving the lever in one direction or the other from a fixed point the
quadrent is also moved simultaneously. Pins or projections are placed on the
two catches which rest on a fixed piece of metal of such a form that the catch
opposite to the direction of the motion of the lever is lifted out of the notches
of the quadrent when moving from the fixed point above mentioned, and is
maintained in that position until the lever returns again to that point.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Davey and David Davy in the Great Seal Patent
Office on the 3rd January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HENRY
DAVEY and DAVID DAVY, both of Sheffield, in the County of York, Engineers,
send greeting..

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of July, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first year of Her. reign,
did, for Herself; Her heirs and successors, give and grant unto us, the said
Henry Davey and David Davy, Her special licence that we, the said Henry
Davey and David Davy, our executors, administrators, and assigns; or such
others as we, the said Henry Davey and David Davy, our executors, adminis-
trators, 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 CENTRIFUGAL GOVERNORS AND MEANS
OF GOVERNING STEAM AND OTHER ENGINES," upon the condition (amongst others).
that we, the said Henry Davey and David Davy, our executors or adminis-
trators, by an instrument in writing under our, 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 immediately after the date of the said Letters Patent...
NOW KNOW YE, that we, the said Henry Davey and David Davy, do
hereby declare the nature of our 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 two Sheets of Drawings
hereunto annexed, and to the letters and figures marked thereon (that, is
to say):
:
Our Invention has for its object the more perfect governing the speed of
steam and other engines, and consists, first, in a means by which the balls.or
pendulums of the centrifugal governor are made to. move in a true or
approximate parabolic curve when moving. from one plane of: rotation. to
another; also in a means by which the pendulums are made to give motion
to the valve, valves, or gear, so that when moving from one plane of rotation
to another they shall in moving through equal lengths of the curve which
they describe produce truly or approximately equal results; and also in the
mode by which the throttle or governing valve is attached to the gear of the
governor; so that when the balls are at rest or in their lowest plane of rotation
the throttle or governing valve is closed. The spindle around which the
pendulums revolve is according to this Invention provided at top. with a
curved horn or horns:. The arm by which the weight is suspended forming
the pendulum is made of a flexible material, by preference steel, and is
'

page_text: secured to the horn at or near the extremity in such a manner that the arm
forms a tangent to the curve of the horn from which it is suspended, which
curve can be made of such a form that the pendulum in moving from one
plane. of rotation to another is caused to move in a true or approximate
parabolic curve. The pendulums in moving from one plane of rotation to
another move between forked arms (or on arms not forked) of a metal tube
or socket sliding on the spindle of the governor. The arms last mentioned are
provided with curved slots in which pins attached to the balls or weights of the
pendulums are made to slide, or the arms may be solid, but the slots or arms
so curved that equal lengths of the curve described by the pendulums produce
true or approximately equal results with the gear acted on. The pendulums
may be employed with any other convenient arrangements in the place of that
last described. The throttle or governing valve may be made of any con-
venient form provided with a port or ports, but according to this Invention it
is so connected to the pendulums that when in their lowest position or nearest
the centre of rotation the port or ports shall be closed or nearly so, as desired,
to obtain which the slot in the arms on or between which the weights move
may be made parallel to the axis of rotation at the extremity nearest the
centre of rotation. In place of the lever ordinarily employed for throttle
valves we place on the spindle a quadrant provided with ratchet teeth of any
convenient form on its periphery, and on one side of the quadrant we provide
an ordinary lever moving loose on the spindle. On the lever we provide two
pawls or catches kept in gear with the quadrant by means of springs, and so
arranged that on moving the lever in one direction or the other from a fixed
point the quadrant is also moved simultaneously. Pins or projections are
placed on the catches which rest on a fixed piece of metal of such a form that
the catch opposite the direction of the motion of the lever is lifted out of the
notches of the quadrant when moving from the fixed point above mentioned,
and is maintained in that position until the lever returns again to that point.
DESCRIPTION OF DRAWINGS.
Our Invention is illustrated in the accompanying Drawings, Figures 1
and 2 showing front and side elevations of a governor such as we employ.
A and B are the horns fixed on the top of a spindle C driven as usual,
around which the balls or pendulumis D, D, revolve; E, E, are the flexible
arms of the pendulums (made of any material, by preference steel,) by which
the balls or weights D are suspended from the curved horns A and B. A
curve for the horns is thus formed:-Construct the parabolic curve 7, 8, and
from any points in the curve draw lines at right angles to the centre line of

page_text: rotation, and from each of the points on the centre line thus formed set off on
that line the required height, and from the points 1, 1, 1", &c., on the curve
draw, lines through each of the points 2, 21, 23, &c., respectively; the inter-
section of those lines on the other side of the centre line will determine, the
form of the curve, or we may use an approximation to such a curve as desired.
G is a metal tube sliding on spindle C, and provided with forked arms H, H,
between which the weights D move, the pins, a, a, of said weights sliding, in
curved slots b,.b, of the forked arms H; we may also make the arms without
slots or solid, in such case we provide pins or projections. on the weights or
balls on one or both sides of the arms. The curve of the arms may thus be
set off:-Divide the curve described by the weight D when moving from one
extreme plane of rotation 4. to the other 5 into any number of equal parts, and
from the points thus obtained draw lines to the arms parallel to the centre
line of the spindle C of rotation, making the length of each line proportionate
either directly or inversely to its distance from the points. 4. or 5. We
use the curve thus formed or an approximation to it as desired. .K is a
chamber provided with a piston for regulating the action of the pendulums
on the throttle valve, the passage of air being regulated by the conical
plug k.
..
'
Figures 3 and 4 represent, our improvements as applied to an ordinary
arrangement of governer, Figure 3 being a sectional elevation of the, same,
and Figure 4 a view at right angles thereto. In this case the balls or
pendulums D are connected by links F to the sliding socket G in' the usual
way while they are attached to the curved horns A, B, above as before described.
The sliding socket G is also.connected to the valve gear as usual, except that
we provide a spring a fixed to a bracket at the upper part of the hollow
tube 6 enclosing the governor spindle C; this spring a is intended to act on
the bell-crank lever. c (forming the connection between..the weights D..and
the throttle valve) so as to keep the said lever and sliding socket G raised
sufficiently to prevent the valve closing when the engine. is working at the
proper speed, while in the case of the gearing d breaking from any cause the
weight of the balls will preponderate and overcome the pressure of the spring.
and so allow the steam to be shut off at the throttle valve. In, this arrange-
ment we regulate the action of the balls on the throttle valve by means of a
collar e fixed on the spindle C, over, which collar the socket G slides freely, and
being hollow and open at bottom on the socket rising a. partial vacuum is
produced above the collar causing the air to pass up around said collar, so
opposing a certain resistance to the rise of the balls and socket, while the
air contained above the collar will similarly regulate the downward motion

page_text: of the balls.
We also curve the arms or slots when necessary as in Figure 5,
which represents the relative positions of the pendulums D, D, and the
throttle valve O when the former are used in connection with the latter, that
is to say, the pendulums (or pendulum) are moved from the centre of rotation
when the valve is full open to a distance sufficient, that in falling towards the
centre of rotation to its extreme limit 6 it closes the valve, or approximately
so, to obtain which the slots 6", 6", in the arms H, on or between which the
weights D move, may be made parallel to the axis of rotation at the extremity
nearest the centre of rotation. We do not confine ourselves to the simple
connection between the valve and pendulums, as shown in the Drawing, but
any system of levers most suited to each particular case may be employed.
Further, in place of the lever ordinarily employed for working throttle valves
we place a toothed quadrant Q on the valve spindle R, as shown at Figure 6,
which is a side view, Figure 7 a plan, and Figure 8 a. transverse section of the
valve and parts. S is a lever fitted loose on the valve spindle R; d', d', pawls or
catches mounted on lever S, and kept in gear with the quadrant Q by means
of springs,e', e¹. . T is a fixed piece of metal serving to raise one or other of
the catches d from the quadrant Q when the lever S in connection with. the
governor and with it the quadrant Q is moved in one direction or the other
from a fixed point, and maintaining it in that position until the lever S returns
again to that point.
Having described the nature of our Invention, and the manner in which the
same may be efficiently performed, we have to state that we do not limit or
restrict ourselves to the precise details herein described or delineated, but that
what we declare that what we claim as our Invention to be protected by the
berein-before in part recited Letters Patent is,-
1st, the application of a curved horn (or horns) from which the pendulums
of centrifugal governors may be suspended, substantially as herein described.
2ndly, constructing the pendulum arms of a flexible material (by preference
steel), substantially as herein-before described.
3rdly, constructing the forked or other arms on or between which the
pendulums move of a curved form and substantially in the manner herein-
before described.
4thly, arranging the pendulums so as to obtain the relative positions described
with reference to the opening and closing of the throttle valve, substantially in
the manner herein-before described.
5thly, the arrangement of quadrant lever and catches applied for operating
the spindles of throttle valves, substantially in the manner herein described and
delineated.

page_text: We also claim the application of the various improvements herein described
ither separately or in combination.
In witness whereof, I, the said Henry Davey, for myself and on behalf
of the said David Davy, have hereunto set my hand and seal, this
First day of January, in the year of our Lord One thousand eight
hundred and sixty-eight.
HENRY DAVEY. (L.S.)