IMPROVEMENTS IN MOTIVE-POWER ENGINES, ALSO APPLICABLE TO PUMPS OR MEASURES FOR AIR, GASES, OR LIQUIDS
Year: 1875

page_text: LETTERS PATENT to Edward Cory, of Cardiff, in the County of
Glamorgan, Civil Engineer, for the Invention of "IMPROVEMENTS IN
MOTIVE-POWER ENGINES, ALSO APPLICABLE TO PUMPS OR MEASURES FOR AIR,
GASES, OR LIQUIDS."
Scaled the 4th May 1875, and dated the 25th January 1875.
PROVISIONAL SPECIFICATION left by the said Edward Cory at
the Office of the Commissioners of Patents, with his Petition, on
the 25th January 1875.
I, EDWARD CORY, of Cardiff, in the County of Glamorgan, Civil
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN MOTIVE-POWER ENGINES, ALSO APPLICABLE TO PUMPS, OR
MEASURES FOR AIR, GASES, OR LIQUIDS," to be as follows:-
My Invention consists of two or more revolving pistons working in a
casing or cylinder and actuated by eccentric wheels or gearing, which
at certain parts of the revolution and while passing the steam inlet or
port cause the area of the relative leading piston upon which the steam

page_text: acts to travel faster than the area of the piston immediately following,
upon which the steam presses with equal force. The steam thus acts
upon the area of the relative leading and following pistons with equal
pressure, but the difference of leverage from the eccentric gearing
compels the pistons to revolve in continuous rotation, obtaining the full
power of the steam together with the momentum of the moving parts.
A reverse action takes place upon the area of the pistons while passing
the exhaust or steam outlet.
The same Invention can be applied as a water-power engine, and if
driven from the exterior will act as a pump or exhauster for air, gases,
or liquids, and with the addition of an index to register the number of
revolutions; it may also be applied as a meter or measurer of gases or
liquids.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Cory in the Great Seal Patent Office 1
on the 24th July 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
CORY, of Cardiff, in the County of Glamorgan, Civil Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 2
Letters Patent, bearing date the Twenty-fifth day of January, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
cighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Edward Cory, Her special licence,
that I, the said Edward Cory, my executors, administrators, and 2
assigns, or such others as I, the said Edward Cory, 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 a
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
MOTIVE-POWER ENGINES, ALSO APPLICABLE TO PUMPS OR MEASURERS FOR AIR,
GASES, OR LIQUIDS," upon the condition (amongst others) that I, the
said Edward Cory, my executors or administrators, by an instrument

page_text: 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 I, the said Edward Cory, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement :-
Mainly the object of this Invention is to avoid retrograde motion in
engines, whether moved by steam or otherwise, which destroys
momentum; and to construct an engine that will travel at a high speed
and have all its parts continually moving forwards; and my said In-
vention consists of two or more revolving pistons working in a casing or
cylinder and actuated by eccentric wheels or gearing, which at certain
parts of the revolution, and while passing the steam inlet or port, cause
the area of the relative leading piston upon which the steam acts to
travel faster than the area of the piston immediately following, upon
which the steam presses with equal force. The steam thus acts upon
the area of the relative leading and following pistons with equal
pressure, and by the difference of leverage from the eccentric gearing
compels the pistons to revolve in continuous rotation, obtaining the
full power of the steam together with the momentum of the moving
parts. A reverse action takes place upon the area of the pistons while
passing the exhaust port or steam outlet.
The same Invention can be applied as a water-power engine, and if
driven from the exterior will act as a pump and exhauster for air, gases,
cr liquids, and with the addition of an index to register the number of
revolutions, it may also be applied as a meter or measurer of gases or
liquids.
The engine is constructed as hereafter described, with reference to the
accompanying Drawings. A, A, Figs. 1 and 2, is the cylinder with
covers and stuffing boxes B, B. Steam is admitted through the
passage C, C, and exhausted through the passage D, D; E, F, are two
pistons, each occupying the full depth of the cylinder but notched on to

page_text: cach other at the boss (see Fig. 4). To the piston E is attached the
shaft G, and to the piston F the shaft H, thus making the pistons
independent of each other. On the shaft G is fixed the wheel I, and on
shaft the wheel J. Geared into these wheels are the wheels K and L
on the shaft M, which thus connect the pistons. The wheels I, J, K,
and L, however, are toothed eccentric wheels, and their action is such,
that they cause the steam space between the pistons to enlarge while
passing the steam passage C and close while opposite the exhaust
passage D.
When each piston occupies one third of the cylinder, the eccentricity
should be as 2 to 1, but this size is not arbitrary, though a different
eccentricity will require different sized pistons. The wheels K, L, may
be the same size as the wheels I, J, when they are of the same form,
but if larger they must be so constructed that the radii of each pair
are at all times equal; the shaft M will then revolve steadily.
The steam passage C, by shortening its length, may be formed so as
to cut off the steam at any required period of the revolution, when the
engine will work expansively. This may be either permanent in the
casting or effected by means of valves or cocks inserted in the passage C
(Fig. 1). A means of doing this is shown at Fig. 7, where a moveable
flap valve closes the passage at a fixed portion of the revolution; several
of these valves may be inserted in the passage, and opened or shut from
the outside either by hand or by the governor.
The steam passage C may also be formed with gridiron openings to
the interior of the cylinder, and a gridiron slide valve working in the
passage. If the openings are of unequal width, the valve by being
drawn over them can be made to gradually close them from one end of
the passage C to the other. A solid partition entirely filling the area of
the passage C and drawn from one end to the other has the same effect,
or an expansion valve may be applied to the steam pipe.
A four-way cock or any other suitable arrangement may be attached
to the pipes, whereby the steam is admitted through the passage D, D,
and exhausted through C, C, when the engine will run the reverse way.
The pistons should also be packed to prevent the steam from passing
from one side of the pistons to the other, and to prevent any leakage of
steam to the exhaust port. I prefer metallic packing for the purpose

page_text: of either a triangular or a square section, and acted upon by springs and
V picces or the elastic force of the steam.
For the pistons I sometimes use packing as shown at Fig. 8, where A,
A, A, are sections of triangular strips of metal, the bottom one being
5 acted upon by springs B which force the two upper strips upwards and
outwards against the cylinder, the ends being either mitred or made
tight with V picces and springs. For the bosses of the pistons, rings,
as shewn at C, may be used, the sections D, D, being triangular. A
disc may also be attached to each piston equal to the full area of the
) cylinder, and the steam admitted behind them, thus forming a steam
jacket; or the two discs may be fixed to one piston and the other
allowed to work between them.
The action of the steam on the pistons, when admitted through the
passage C, is as follows:-At the point N, Fig. 1, the surfaces of the
pistons E and F are together, but as the steam enters between them
the leading piston travels faster than the follower, and continues to do
so until the steam is cut off by the following piston. The pressure
during the time is equal on each surface, but the mean leverage on the
leading piston is double that of the follower, and the latter is therefore
› compelled to revolve.. There is, however, no loss of power by this action
as the area of the leading piston has in the meantime traversed a portion
of the revolution equal to double the cubic capacity of the steam used.
This action therefore is continually repeated as the spaces between the
pistons are alternately brought opposite the steam passage C, C, that is,
the steam space continually increases in capacity while passing the
steam passage C, C, and decreases while passing the exhaust passage D, D;
and although the normal pressure is equal on each piston, the leverage
from the eccentric wheels is such, that one piston is compelled
alternately to follow the other without loss of power. To actuate the
pistons in a similar manner they may be geared togetlier by means of
levers when the wheels can be dispensed with. An example of this is
shown at Figs. 5 and 6. In Fig. 5 the axle or shaft of each piston
forms a hollow trunk A, to which is attached a crank pin B working in a
guide block. This guide block slides in the slotted crank C which is
attached to the main shaft D, whose centre does not coincide with the
centre of motion of the crank pin B. A similar arrangement for the
other piston is on the opposite side of the cylinder, the shaft D being

page_text: continued through the trunk A. In Figure 6, the two piston shafts are
made to protrude on the same, side of the cylinder, one of them being
hollow. To each of these are attached the crank A and B with their
respective crank pins and guide blocks C and D. These work in the
double crank E, whose shaft F is also out of centre with the centre of t
motion of the piston cranks. When this double crank is in a vertical
position it is obvious the upper piston crank has the advantage in the
leaverage over the lower one.
Another way of gearing the pistons together is as follows:-The main
shaft being out of centre with the centre of the cylinder, as in Figs. 5 1
and 6, the interior part of each piston is made hollow and open to the
trunk, and two cranks at angles of 180° upon the main shaft protrude
into the hollow of their respective pistons connected thereto by short
links, one end of each link being connected to the end of its crank and
the other to the piston; when arranged in this manner the trunk may 1
be closed at each end, the main shaft only protruding through the covers
and steam admitted to the interior of the pistons and trunk.
Similar arrangements may also be used for a pump, water-power
engine, air pump, or exhauster, or measurer of fluids or gases, in which
latter case an index of revolutions would be attached. For the same
purposes three or more pistons may be used instead of two, each
being attached by wheels or gearing, the conditions being, that in
passing the steam port the area of the leading piston, acted upon by the
steam, shall travel faster than the one immediately following, and in
passing the exhaust port a reverse motion shall take place.
Having now particularly described and ascertained the nature of my
said Invention, and in what manner the same is to be performed or
carried out in practice, I hereby declare that I claim the said Invention
of "Improvements in Motive-power Engines, also Applicable to Pumps
or Measurers for Air, Gases, or Liquids," wherein the action of the steam
upon revolving pistons, whereby the leading piston while passing the
induction port has a greater leverage upon the main shaft than
the following piston, the reverse action taking place while passing the
eduction port, are peculiar and important features; as by this means I
gain the full benefit of the momentum of all the moving parts of the
machine, as there is no retrograde motion; I also consider an important

page_text: and peculiar feature the above described means of regulating the
expansion.
In witness whereof, I, the said Edward Cory, have hereunto set
my hand and seal, this Twenty-second day of July, in the year of
our Lord One thousand eight hundred and seventy-five.
EDW³. CORY. (L.S.)