IMPROVEMENTS IN APPARATUS FOR REGULATING THE SPEED OF ENGINES
Year: 1881

page_text: LETTERS PATENT to William Wallace Girdwood, of No. 9, Lea Cottages, East
India Dock Road, Poplar, in the County of Middlesex, Engineer, for an
Invention of "IMPROVEMENTS IN APPARATUS FOR REGULATING THE SPEED
OF ENGINES."
PROVISIONAL SPECIFICATION left by the said William Wallace Girdwood
at the Office of the Commissioners of Patents on the 26th November 1881.
WILLIAM WALLACE GIRDWOOD, of No. 9, Lea Cottages, East India Dock Road,
Poplar, in the County of Middlesex, Engineer. "IMPROVEMENTS IN APPARATUS
FOR REGULATING THE SPEED OF ENGINES."
My Invention has for object improvements in apparatus for regulating the speed
of engines. Now according to my Invention a hollow wheel containing liquid is
mounted upon suitable bearings, and has one of its journals extending through one
of its bearings, to which journal is attached a disc having a pin fixed at right
angles to it; I will hearafter call this disc and pin a crank disc; I next have a driving
pulley, which is also mounted upon suitable bearings, and is in the same axial line
as the hollow wheel. One of the journals of tho driving pulley extends through
its bearing nearest the wheel and has a disc attached to it. Further, conceive a
spindle passing through the centre of the driving pulley, and free to move in any
circular direction, and upon its extremity nearest the wheel a small pinion is fixed.
This spindle and its pinion must be imagined to remain stationary untill
particular occasions, when it has a slight rotary motion given to it; upon the disc
of the driving pulley is fitted a pin at right angles to it, and to the pin I attach
the central portion of a volute spring, which is wound to a certain tension and is
then enveloped by a metallic drum, which is capable of rotating upon its own axis,
and thereby convolving the spring; upon the drum is fixed a cog wheel which
gears into and rotates round the small pinion and spindle before mentioned; the
crank disc of the hollow wheel is next attached to the periphery of the drum by
suitable connections, such as a steel band or flexible chain. If the driving pulley

page_text: which is driven by the engine to be controlled be now put in motion, and so long
as that motion is uniform and steady, the drum with its cog wheel will simply
describe its orbit round the central small pinion and spindle which passes through
the driving pulley without affecting in any degree whatever the said pinion and
spindle. But should the pulley receive increments of speed, they are not trans-
mitted directly to the hollow wheel, but impart first an episcycloidal motion to the
drum and its cog-wheel, which in its turn rotates the central pinion and its spindle ;
this spindle projects beyond the other extremity of the driving pulley and has a
lever fixed to it, from the angular motion of which I derive action for opening or
closing the steam valvo, either by direct communication or by the assistance of an
auxiliary steam cylinder, in which latter caso it would be connected to the small
slide valve thereof; when the speed of the driving pulley was increased we should
have found that owing to the episcycloidal movement of the drum a further con-
volution of the contained spring resulted, but when the speed decreases an
evolution of the spring results, and hence a reverse movement in the lever of the
central spindle; the pin upon which the central portion of the spring drum is fixed
passes through the disc of the driving pulley and is connected to a ratchet and
pawl arrangement for increasing the tension of the spring at pleasure; upon the
proper adjustment of the spring uniformity of motion is guaranteed to the engine
being governed by this apparatus.
The mechanism I have described is what I use for very accurate and steady
working, but I may also use in conjunction with the hollow wheel containing
liquid the samo mechanism as was described in the Specification of Patont granted
to me 11th September, A.D. 1880, No. 3706.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Wallace Girdwood in the Great Seal Patent Office on the
25th May 1882.
WILLIAM WALLACE GIRDWOOD, of 9, Lea Cottages, East India Dock Rd.,
Poplar, London, E., in the County of Middlesex, Engineer. "IMPROVEMENTS IN
APPARATUS FOR REGULATING THE SPEED OF ENGINES."
My Invention has for object improvements in apparatus for regulating the speed
of engines. According to my Invention a hollow wheel containing liquid is
mounted upon suitable bearings and has one of its journals extending through one
of its bearings, to which journal is attached a disc having a pin fitted at right
angles and excentrically to it. I will refer to this disc and pin as a crank disc.
I next have a driving pulley which is also mounted upon suitable bearings, and is
in the same axial line as the hollow wheel. One of the journals of the driving
pulley extends through its bearing nearest the hollow wheel, and has a disc
attached to it. Further, I have a spindle passing through the centre of the driving
pulley and free to move in any circular direction, and upon its extremity nearest
the hollow wheel a small pinion is fixed; this small pinion and spindle must be
imagined to remain stationary until an acceleration in the speed of the engine to
be controlled occurs, when it has a slight rotary motion given to it. Upon tho
disc of the pulley is fitted a pin at right angles, and excentrically to it and to the
pin I attach the central portion of a volute spring, which is wound to a certain
tension and is then enveloped with a metallic drum, which is capable of rotation
upon its own axis. The circumference of this drum assumes the form of a cog
wheel, which gears into and rotates round the central small pinion and spindle
before mentioned as passing through the driving pulley. The crank disc of the
hollow wheel is next attached to the periphery of the drum, either by a flexible
chain, steel tape, or solid connecting rod. The pin upon which the spring drum is
fixed, passes through the disc of the driving pulley, and is connected to a ratchet
and pawl arrangement for increasing the tension of the spring when the apparatus
is at rest. If the driving pulley, which is driven by the engine to be controlled,
be now put in motion, and so long as that motion is uniform and steady, the spring
drum with its cog wheel will describe its orbit round the central small pinion and
spindle, which passes through the driving pulley without affecting it in any degree
whatever, but should the pulley receive increments of speed, they are not
transmitted directly to the hollow wheel, but impart, first, an episcycloidal motion
to the spring drum and its cog wheel, which in its turn rotates the central small
pinion and spindle. Upon the other extremity of this central spindle is fixed a
lever, from the angular motion of which I derive action for either opening or
closing the steam valve of the engine to be controlled. The angular motion of this
lever is opposed by a spiral spring which is capable of delicate adjustment. When
the speed of the driving pulley increased, then the episcycloidal movement of the
spring drum caused a further convolution of the contained spring, but when the
speed decreases an evolution of the spring occurs, and hence a reverse movement
in the lever of the central spindle results, which is further assisted by the spiral
spring. The hollow wheel containing liquid must be very light and weight inust
be annihilated (if possible); it may be made of metal, wood, glass, or any other
known material. If the wheel is composed of iron, brass, or wood, then it should
contain oil or water, but if of glass then it should contain mercury. I do not

page_text: confine myself to use any particular substance for the composition of the wheel,
nor do I confine myself to use any particular liquid. The liquid must have a
definite proportion by weight to that of the wheel and its shaft; the weight of
liquid should predominate; the object of this is to entirely obliterate any momentum
that might be stored up in the revolving wheel. The level of the liquid must
allways be below the centre of tho wheel, and the summit of the wave lino
formed by its motion must not pass the centre line. In some cases I put a float
inside the wheel, covering as near as possible the surface of the liquid in order to
preserve its quiescence; above all, the wheel must not be full of liquid, because in
that case it would assume a circular notion by the rotation of the wheel, and its
presence there become nugatory as a means of offering resistance to the motion of
the wheel. By uscing a light wheel in which the weight of liquid predominates,
motion is weighed, and at various speeds the wheel offers various resistances, and
it is the refusal of the hollow wheel to receive increments of speed that causes the
episcycloidal movement of the spring drum, with the result before described. I am
aware that for the regulation of the speed of engines wheels containing liquid have
been revolved, as also fans have been revolved, in a casing containing liquid, and in
both these cases the results would be a little inaccurate, because, in the first
instance, the wheel possessed more weight than the liquid, and the inertia of the
revolving mass would not be compensated for by the insignificant resistance of the
contained liquid; and, in the other case, the inertia of the revolving fans and
the rotary motion of the liquid would form (in toto) a fly wheel, which I find to be
an inaccurate standard of resistance. Now my Invention consists in the con-
struction of apparatus wherein inertia, centrifugal force, and impact are extruded
as being antagonists of a perfect governor.
I will now by the aid of the accompanying Sheet of Drawings more particularly
describe the machine and its mode of action. Fig. 1 shows a transverse view of
the machine. A is the hollow wheel; B, the driving pulley; C is the central
spindle, and is shown in section with the lever b, b, being in connection with the
steam valve and spiral spring, which is enveloped with a graduated scale for
registering the pressure. Fig. 2 is a longitudinal elevation, the driving pulley B,
the crank disc, and shaft of the hollow wheel being shown in section, as also is the
hollow wheel itself shown in section, but being of a very light material can only be
depicted by a line; C is the central spindle, and is not shaded; D is the pinion
fixed upon its extremity near the wheel, and b, b, is the lever fixed upon the other
extremity; E is the spring drum with its cog wheel gearing into D, and capable of
rotating round it; F is the ratchet and pawl arrangement on the one side of the
driving pulley's disc at B', with the volute spring fixed upon the ratchet spindle on
the other side of the disc at 133. The spring drum E is shown connected by a steel
tape G to the crank disc H on the one extremity of the journal K, which is the shaft
of the hollow wheel; L is the liquid, with the float Al shown in section. Fig. 6
shows transverse view of the hollow wheel, with crank disc H. Fig. 5 is trans-
verse section of the hollow wheel, showing section and disposition of the float.
Fig. 4 is transverse view of driving pulley's disc at B', showing ratchet and pawl
arrangement for increasing the tension of the spring when the apparatus is at rest;
the central portion of the volute spring is attached to the ratchet spindle upon the
other side of the disc at B. Fig. 3 shows transverse view of driving pulley's disc
at B; E is the spring drum gearing into the pinion D of the central spindle C; G is
the steel tape connecting the spring drum and crank disc H of the hollow wheel;
the volute spring is represented by a number of concentric circles, and is attached
to the ratchet spindle F, which is shown in section. Now immediately there is
any attempt of the driving pulley, and hence of the spring drum, to travel faster
than the hollow wheel, the distance between H and E would increase, causing E
to revolve slightly, thus giving to the pinion D a rotary motion, also an angular
motion to the lever b, b, acting on the parts operating on the steam valve.
Having now described the said Invention of machine for regulating the speed of

page_text: engines, and the manner in which the same is or may be brought into practical
use,―
I claim, First. The light hollow wheel containing liquid, substantially as set forth
and for the purpose specified.
Secondly. The combination of mechanism and arrangement of parts forming
together with the light hollow wheel containing liquid a suitable regulator for the
working of steam engines.
In witness whereof, I, the said William Wallace Girdwood, have hereunto set
my hand and seal, this Twenty fifth day of May, in the year of our Lord
One thousand eight hundred and eighty two.
WILLIAM WALLACE GIRDWOOD. (L.S.)