Improvements in Rotary Engines or Pumps.
Year: 1897

page_text: Date of Application, 20th July, 1897--Accepted, 2nd Oct., 1897
COMPLETE SPECIFICATION.
Improvements in Rotary Engines or Pumps.
I, GEORGE BOHAN SHEPARD, of Ogdensburg, in the County of St. Lawrence, State
of New York, United States of America, Attorney at Law, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
My invention relates to that class of rotary devices adapted to be used either as a
motor by the force of any fluid under pressure; or, when rotated by outside force,
as a pump (both suction and force) for air, gas, water, or any fluid; or for a meter
for gas, water or any other fluid; and the objects of my invention are to provide a
motor, or pump, or meter that can be cheaply and easily made and repaired, run at
high speed with the smallest amount of wear or vibration, and readily reversed, and
that will be positive in its action, and economical in its operation, and at the same
time simple and compact in construction.
My invention consists first in the combination in a rotary device of two parts, one
encircling the other, one of which is adapted to revolve with reference to the other,
and one of which parts is provided with a cam surface having portions concentric
with the axis of rotation but at different distances therefrom and inclined portions
connecting the concentric portions, all of these portions together forming a cam
surface upon which the bearing surfaces at or near the ends of the gates bear and
ride, and the other part having a surface in part or in whole concentric with the
axis of rotation so as to fit closely against the raised part of the cam surface above
described and thus form pockets between the two parts of the device, and a double
headed gate having bearing surfaces at or near both ends, the gate being so constructed
and arranged that the ends of the gate will be in contact with the cam surface
substantially all of the time so that the cam surface will move the gates back and
forth, whereby both ends of the gate are successively brought into operation and
made to form a part of the walls of the working chamber in which the pressure is
exerted which gives to the device the rotary motion. Instead of providing the cam
surface with inclined portions, the inclines may be formed on the ends of the gate,
and the concentric portions of the cam surface may be connected by a straight radial
In both
surface forming a square shoulder or by any suitable kind of surface.
cases the gates are moved back and forth by the action of the cam surface
bearing against the ends of the gate. There must be an inclined surface on
one or the other, so as to cause a gradual movement of the gate back and forth.
prefer to provide the cam surface with an inclined connecting portion.
I
My invention also consists in the combination with the other parts, above
mentioned of a plurality of double-headed gates such as above described whereby
the rotating part is balanced on its axis and is relieved from sidewise twist or
strain.
My invention also consists in making all the portions of the cam surface which
are concentric with the axis of rotation, including both the raised concentric
portions, and the depressed concentric portions, of substantially equal arc, and at an
equal distance from one another, whereby the pockets are made more symmetrical,
and the operation of the device is more steady and uniform and an extended steam

page_text: or fluid joint is secured between the raised portion of the cam surface and the other
part of the device.
My invention also consists in making the inclined connecting portions of the cam
Burface of substantially equal arc with the concentric portions; it also consists in
making these inclined portions of a uniform curve, that is, a curve described with
the same radius.
My invention also consists in arranging the gates so that they are at an equal
distance from each other, and in employing the same number of gates as there are
raised concentric portions on the cam surface.
My invention also consists in providing the part of the device which does not
carry or support the cam surface, with interior slots, that is, slots which are on the
interior of the device as distinguished from slots or openings that extend through
the wall or casing to the exterior, the said interior slots being adapted to hold and
guide the double-headed gates and to permit them to be moved back and forth by
the action of the cam surface, whereby a self-contained device is secured which is
simpler in construction and better in other respects than those rotary devices
heretofore in use in which the gates were moved back and forth through openings
in the shell or casing of the engine provided with packings and were supported and
operated by means on the exterior of the engine.
My invention also consists broadly in the combination of two parts, one encircling
the other, and one revolving with reference to the other, and one provided with a
suitable cam surface, of a double headed curved gate having bearing surfaces at or
near both ends, the gate being so constructed and arranged as to bring both ends
successively into operation in the manner above explained, whereby the friction
upon the gate is reduced, and the power of the device correspondingly increased.
My invention also consists in making the double-headed gate in two parts, and
connecting these parts by a suitable spring device.
My invention also consists in the combination with some or all of the parts
already mentioned of a secondary drum and shell and gates similarly constructed
and arranged, the inlet port of the secondary part being connected in axial line with
the outlet port of the primary part or substantially in this way whereby the corre-
sponding parts of the secondary device are advanced somewhat around the axis or
shaft, and the combined action of the two parts of the device produces a steadier
and more uniform motion and speed.
My invention also consists in certain other features of construction and
combinations of parts hereinafter described and claimed.
My invention is specifically illustrated in the accompanying drawings, in which
Fig. 1 is a sectional view on the line x x of Fig. 2 looking from left to right;
Fig. 2 is an end view with one of the face plates removed and showing a section of
the lower gate; Fig. 3 is a perspective view of one of the double-headed gates;
Fig. 4 is a sectional view of a compound arrangement on the lines y
and z of
Fig. 5, looking from left to right, the primary being sectionalized on the line y y
of Fig. 5 and the secondary being sectionalized on the line y z of Fig. 5, looking
from left to right; Fig. 5 is an end view of Fig. 4 with one of the face plates
removed, showing the lower gate in section the dotted lines showing the relative
position of the compound; Fig. 6 is a sectional view of another form of my invention,
made on the line z z of Fig. 7; Fig. 7 is a sectional view on the line ww, of
Fig. 6, the left hand gate and the drum being shown in full and the right hand
gate being shown in section. Fig. 8 is a perspective view of the form of gate
shown in Figs. 6 and 7; Fig. 9 is a sectional view of a modification of my invention
provided with cut-offs; Fig. 10 is a perspective view of the form of gate shown in
Fig. 9; Fig. 11 is a side view of a double-headed gate in which the inclines are
placed on the gate-head; Fig. 12 is a bottom or plan view of the gate shown in
Fig. 11 looking from below; Fig. 13 is a vertical sectional view of the rotary device
having gates like that shown in Figs. 11 and 12, with the inclines on the gate-heads;
Fig. 14 is a view similar to Fig. 12, showing the inlet and outlet ports in the
gate-heads; Fig. 15 is a sectional view of such a rotary device, made on an axial

page_text: plane but showing the ports passing through the shaft and drum instead of through
the shell and gate-heads; Fig. 16 is a vertical sectional view of the form shown
in Fig. 15 made on a line perpendicular to the axis.
Similar numbers and letters indicate similar parts in the different figures.
Referring now to the simple form shown in Figs. 1, 2, and 3, 1 represents the
shaft and 2 a drum or disc secured thereto so as to revolve therewith, and 3, 3,
the face plates and 4 a ring provided with a cam surface. The face plates and the
ring together surround the said revolving drum, forming an encircling shell or casing
therefor. The said ring is located upon said face plates by means of an annular
groove or shoulder formed on said face plates, and the parts are held firmly in place
by means of the bolts 5, which are carried through holes arranged in the rim of said
face plate at suitable distances apart and provided with the nuts shown at either
end, by use of which the said face plates can be held rigidly against the ends of said
ring 4.
The face plates 3, 3, may be provided with a central projection having an internal
thread into which are screwed the shaft journal bearings 6, 6, in the usual manner,
and they may also be provided with radial ribs 7, 7, as shown to strengthen them
against outward thrust.
On each end of the drum 2 are cut two uniformly curved channels, as shown at 8 in
Figs. 1 and 2, exactly opposite each other, those cut on one end of the drum being
parallel with those on the other end thereof; and for a part of their length from each
end the said channels are connected by an axial cross-channel 12, cut entirely through
said drum from end to end. These channels and cross channels together. form slots
for the purpose of holding within said drum double-headed gates 9, one of which is
shown in Fig. 3. These slots hold and guide the gates as they are moved back and
forth. Each gate is cut away in the center to embrace the solid portion of the
drum left between said side channels and cross channels, and in the best form of
my invention is divided in the middle as shown in Fig. 3. Holes are bored into the
end of each of the parts and the spiral springs 10, 10, placed therein to make up for
wear and to force the ends of said gates into any irregularities in the cam surface
hereinafter described.
It is apparent however that the gate may be made in one piece and the part of the
drum on the outer side of the gate may be temporarily detached from the body of
said drum to enable the gate to be placed in position.
The gates may be provided at their bearing surfaces or ends with rocking shoe
pieces 11, fitted into grooves in the gates and adapted to turn or rock therein and
to bear at all times against and to be in constant contact with the cam surface on
the ring 4, as shown in Fig. 2, and to form a substantially tight steam or fluid joint
therewith. It is however apparent that the gates may be used without shoe pieces,
the gates being made long enough so that their ends bear directly against the cam
surface; but in that case all wear would come upon said ends and the gates would
have to be more frequently renewed, while otherwise the wear comes upon the shoe
pieces which are easily renewed by simply removing one of the face plates herein-
before described. The gates are formed to closely fit within the slots formed in the
drum, but with sufficient endwise motion to enable either end to be pushed back
within said drum, but of sufficient width to closely fill the said slots and form a
substantially tight steam or fluid joint therewith and with the inside surfaces of the
face plates and they are of sufficient length so that their outer ends shall at all times
bear upon the can surface of the ring 4 as hereinafter described.
The cam surface on the ring 4 consists of eight distinct portions. There are two
raised portions 13, 13, which are concentric with the axis of rotation, and at such a
distance therefrom that they at all times bear against the circumference of the drum 2
and form a steam or fluid tight joint therewith. They are exactly opposite each
other and are 45° in length, that is to say, the arc of each one is equal to the eighth
part of its circle. There are two depressed portions 14, 14, which are also concentric
with the axis of rotation and exactly opposite each other, and of the same length of
that is to say, each of these portions is 45° in length or the eighth part of its
arc,

page_text: circle. The portions 14, 14, are at a greater distance from the axis of rotation than
the portions 13, as a result of which pockets are formed between these portions 14, 14
and the drum 2. The portions .13, 13, are connected with the portions 14, 14, by
the inclined portions 15, 15. These portions 15 are made with a uniformly curved
surface such as would be struck from a center the radius of which is the mean
between the two radii from which the surfaces 13, 13 and 14, 14, are struck
respectively. They are of the same length as the concentric portions, that is, each
inclined portion 15 extends 45°, measured on a line concentric with the axis of
rotation, occupying therefore one-eighth part of the circle of rotation. The ends of
the gates or their bearing surfaces are formed to fit, at all points of their revolution,
and to bear closely against the cam surface, so as to form a steam or fluid tight joint
therewith. The drum 2 is made with a surface in part or in whole concentric with
the axis of rotation. I prefer to make its entire surface concentric as shown, but
it is manifest that some portions of its surface might be cut away without preventing
the operation of the device.
It will be observed that this form of construction at all times maintains the same
distance between points of said cam surface 90° distant from each other when
measured on radial lines from the axis of said drum; so that, as the said surface
approaches said axis at one point, its surface at a point 90° distant therefrom corre-
spondingly retreats from said axis. Therefore the distance between the said points
along the line of the gates will always be the same, and consequently the ends of
said gates will always bear against the cam surface during their entire revolution with
said drum.
It is apparent that this method of construction forms a series of pockets in the
encircling shell, between the raised concentric portions 13, 13, which pockets consist
first of an expanding inclined curve 15, a depressed concentric portion 14, and a
contracting inclined curve 15; and that any desired number of such pockets may be
formed in the said shell, if the above described relative proportions of the parts be
maintained as above explained, so that both ends or bearing surfaces of said gates
shall at all times bear upon the cam surface. In the best form of my invention it is
essential that such pockets shall be two or more in number and equidistant circum-
ferentially of said drum; or otherwise, when steam or other propulsive force is admitted
into said pockets as hereinafter described, the balance of said drum would be
destroyed and excessive friction against its rotation be caused. All of which I avoid
by the construction already described.
For the purpose of supplying propulsive force to rotate said drum I provide inlet
ports 16, 16, through said ring at about the middle of said expanding incline on said
cam surface, and outlet ports 17, 17, similarly situated on the incline at the other
end of the pocket, and cut channels 42 from said ports in both directions as shown, to
prevent a vacuum being formed between the raised portions 13 and the ends of said
gates as they revolve. While it is desirable to have the outlet ports somewhat larger
than the inlet ports, they may be constructed of the same size as herein illustrated
and used interchangeably for the purpose of reversing the direction of rotation of
said drum. Or, instead of being cut through the face plate as shown, said ports or
either of them may be cut directly through the ring 4.
In the best form of my invention, series of channels extending entirely across the
ring are employed to connect the ports with the interior of the shell; and the
channels on one side of the device are alternated or staggered with those on
the opposite side of the device, so that the intervening walls between the channels
on one side will be exactly opposite the channels on the other side. The object of
this is to prevent the uneven wear upon the face of the drum and shoe pieces which
would result from having the channels opposite one another and the intervening
walls opposite one another.
In Figs. 4 and 5, my invention is shown as applied to a compound rotary engine
or device. In this case there is a secondary drum 19 on the same shaft, with similar
gates 20, 20, and a secondary shell on ring 21, provided with a cam surface having
similar raised concentric portions 22, depressed concentric portions 23, and inclined

page_text: connecting portions 24, and secondary inlet ports 25, 25, and outlet ports 26, 26.
The secondary shell and drum are advanced in position around the axis of rotation
relatively to the primary shell and drum so that the inlet ports of the secondary
shell are connected in axial line with the outlet ports of the primary shell, the
same relative positions of shell, drum, gates and ports being preserved in the secondary
device as in the primary device.
In Fig. 5, the cam surface, the gates and the ports of the secondary part are
indicated in dotted lines, the full lines showing the corresponding devices of the
primary. The relative positions of the corresponding devices in the two parts are
thus clearly shown.
It will be readily seen that this last device forms what is commonly termed a dry
compound engine when steam is used. The relative proportions of the primary and
secondary pockets can be varied as desired to obtain the best results, and additional
drums, shells and gates, may be added without destroying the principle of its
operation.
Supports in any form may be attached to the shell or casing to hold it in place, as
represented in Fig. 2, or the casing may be provided with a pulley surface and the
inlet and outlet ports led into said pockets through a hollow shaft and openings in
said drum on each side of the gate ends as heretofore done in rotary engines having
radially moving gates, and the shaft and drum held rigidly in place; when said
casing would rotate instead of said drum and shaft.
In operation, the parts being assembled as hereinbefore described, and steam or
other force being admitted through the inlet ports 16, and being confined between
the opposite surfaces of the face plates, it fills said pockets until at one end thereof
it presses against the raised concentric portion 13 of the cam surface and can go no
further in that direction, and in the opposite direction presses against the end of the
gate 9, with its shoe bearing tightly against the cam surface and filling the space
between the walls of said pocket and the circumference of the drum, and constituting
one of the walls of the said pocket or working chamber, so that it can go no further
in that direction except by forcing forward the end of said gate toward the outlet
port in said pocket, which it consequently does. But before the said gate reaches
said outlet port, the other end of said gate is interposed between said inlet and outlet
ports by the action of the rotation of said drum in which said gates are seated, and
by the positive action of the inclined surface of the further side of said pocket bearing
against the advance end of said gate as heretofore shown. The end of the second
gate is then interposed in similar manner and so on as long as the supply of steam
or other force is continued.
It will be seen that the double-headed gate is so arranged that the portions of the
gate at or near both ends successively constitute one of the walls of the working
pocket or chamber and are positively moved into operative position for that purpose
by the action of the inclined portion of the cam surface upon the bearing surface at
or near the other end of the gate. In the best form of my invention, such as is
shown in Figs. 1 and 2, the end of the gate is not only moved into such operative position
by the action of the cam surface on the other end of the gate, but it is held positively
in that position in the same way during all the time it is travelling along the
depressed concentric portion 14. It would be possible, however, to cut away some
part of the raised concentric portion 13, for example, at the middle part thereof,
without destroying the operation of the device. But this form would be inferior.
It is apparent that a valve of ordinary construction may be interposed in the
supply pipes and operated by an eccentric attached to the shaft in the usual manner to
cut off the said supply of steam at any desired point so as to use the saine expansively,
as is now done in steam engines of different forms. Or, if it is desired to operate
my improved device by vacuum, that can be done by opening the supply pipe to the
air and attaching the exhaust pipe to exhausting apparatus, when the operation of
the device would be similar to that above described. Or, if the supply pipe be
attached to any fluid supply and the outlet pipe attached to a reservoir, and the said

page_text: shaft and drums rotated by outside force, it is apparent that my said motor will act
as a lifting or force pump for any fluid desired.
My invention may also be used as a meter for measuring gas or any other fluid,
by providing it with suitable registering devices to record the number of revolutions,
the size of the pockets being known and it being, therefore, possible to accurately
estimate the amount of gas or fluid passing through it, if the number of revolutions
is known.
In Figs. 6-8, a modification of my invention is shown, in which the cam surface is
formed upon the drum and the gates are supported in the shell or casing. 27, is the
drum; 28, 28, the face plates; 29, the ring; 30, 30, the channels in the face plates
in which the gates slide; 31, 31, the cross channels in which the ends of the gates
are held and slide; 32, 32, the gates, provided with springs 33 to connect their parts
together; 34, the shoe pieces; 35, 35, the raised concentric portions of the cam
surface on the drum; 36, 36, the depressed concentric portions; 37, 37, the inclined
connecting portions; 38, 38, the inlet ports, and 39, 39, the outlet ports.
The cam surface is provided with six raised concentric portions adapted to bear
closely against the concentric surface on the shell, so as to make a substantially
tight steam or fluid joint therewith, instead of having only two such portions as in
the form shown in Figs. 1 and 2. As a result of this each gate is moved back and
forth six times for each revolution of the device. As there are only four inlet ports,
the pockets will at times be simply dead spaces full of steam or fluid, but not
operative in the production of power. The gates, instead of having bearing surfaces
at their extreme ends, are formed with bearing surfaces or shoes near their ends and
at the ends of their middle slots or openings which are adapted to receive and enclose
the drum, as clearly shown in Fig. 8. These ends are preferably grooved, as already
explained, to receive and hold rocking shoes as shown; and these bearing surfaces of
the gates bear against the cam surface on the drum. 40, 40, are projecting parts on
the exterior of the shell in which are contained the cross channels 31, forming a part
of the interior slots in which the gates move back and forth and also the inlet and
outlet ports. The cross channels extend entirely across the inner face of the ring
and join the side channels 30, which are formed on the interior of the face
plates.
The spring 33 is a tension spring secured at its ends to the two parts of the gate
and operating to draw the parts of the gate together and thereby to keep the bearing
surfaces in contact with the cam surface.
The several concentric portions of the cam surface, as well as the inclined connecting
portions, are made of equal arc, and the inclined portions are uniformly curved as
already explained.
The operation of this form of my invention is substantially the same as that of
the form shown in Figs. 1 and 2. After a raised concentric portion of the cam
surface has passed an inlet port, the steam or other fluid enters the pocket between
the said concentric portion and the gate and forces them apart which causes rotation
of the movable part. Either the drum or the shell can be constructed so as to
revolve, or both might revolve.
In Fig. 9 a form is shown similar to that of Fig. 7, except that the drum has but
two raised concentric portions instead of six, and the ports are provided with cut-offs.
These cut-offs are formed by making pockets 41 in the faces of the ends of the gates as
clearly shown in Figs. 9 and 10. The pocket on one side is connected with the inlet
port and the pocket on the other side is connected with the outlet port. These
pockets are so arranged that the moving of the gate out into the case by the
advancement of the inclined portion of the cam surface cuts off both the inlet and
the outlet ports from communication with the working chamber before the end of the
gate is entirely moved out, so that the inlet and outlet ports will not be in
communication simultaneously with the same chamber.
In. Figs. 11 to 14 a form is shown in which the inclines are placed on the ends
of the gates or gate-heads and the ports are formed in the gate-heads. similar
form is shown in Figs. 15 and 16, except that in this case the ports pass through

page_text: the shaft and drum. Referring to these drawings, a represents a shaft and ba
drum or disc secured thereto so as to revolve therewith; c, c, are face plates, and d
is a ring provided with an interior surface which is partly concentric with the axis
of rotation. The face plates and the ring together surround the said revolving
drum, forming an encircling shell or casing therefor. The ring is fastened to the
face plates in any suitable way, as by an annular groove or shoulder formed on the
said face plates, as clearly shown in Fig. 15, and the parts are held firmly in place
by means of the bolts e, which are carried through the holes arranged in the rim of
said face plates at suitable distances apart and provided with nuts at their ends
whereby the said face plates can be held rigidly against the ends of said ring, as
shown in Fig. 15. The shaft a is journaled in the face plates in any suitable
manner.
On the inner face of each face plate are cut two uniformly curved channels, as
shown at f in Figs. 13 and 16, exactly opposite each other, those cut on one face plate
being parallel respectively with those on the other face plate. The said channels are
connected by cross-channels m extending from one face plate to the other, and
forined by the projecting portions of the ring d. These channels and cross-
channels together forin slots for the purpose of holding and guiding within the
casing the double-headed gates, one of which is shown in Fig. 11. These slots hold
and guide the gates as they are moved back and forth, and the gates are in this way
carried by the shell. Each gate consists of the uniformly curved side pieces g g
and the gate-heads h h; these parts are either made solid or are fastened together
in any suitable manner. The gate-heads are provided with bearing surfaces k on
their inner faces and inclined surfaces i; the ends of the gate-head are curved as
shown, to conform to the curved surface of the wall of the cross-channel m, and the
ends and sides of the gate-head are made to closely fit against the walls of the
cross-slot m so as to make a substantially fluid-tight joint therewith; the side pieces
of the gate are also made to closely fit the channels f in the face plates, so as to inake
a substantially fluid tight joint therewith; the channels and the cross-channels m
are made long enough to give sufficient endwise motion to enable either end of the
gate to be pushed out into the projection of the shell. As already stated, the gates
are formed to closely fit within the slots and have a substantially fluid-tight joint
therewith and with the end of the drum, and they are of such length that their
bearing surfaces or inclines, or some part thereof, shall at all times bear upon the
surface of the drum as hereinafter more fully described.
In the form shown in these figures the surface of the drum consists of four distinct
portions; there are two raised portions n n, which are concentric with the axis of
rotation, and at such a distance therefrom that they bear against the concentric
portions of the surface of the ring d and form a substantially fluid-tight joint
therewith; they are exactly opposite each other and are about 45 degrees in length,
that is to say, the length of each one is equal to about one-eighth part of its circle;
there are two depressed portions oo, which are also concentric with the axis of
rotation and exactly opposite each other. Each of these depressed portions, in the
forin shown, is about 135 degrees in length, or three-eighths of its circle. The
portions n n are at a greater distance from the axis of rotation than the portions o o,
as a result of which pockets are formed between these portions oo and the ring d.
In the form shown the portions n n are connected with the portions oo by the
straight surfaces or shoulders p, but it will be apparent that these connecting
portions might be considerably changed so as to be inclined or curved in either
direction without interfering with the operation of the device. The bearing surfaces
of the gates, including the inclined portions, are so constructed and arranged that
some part of said bearing surfaces fits or bears closely against the surface of the drum
at all points of its revolution so as to form a substantially tight steam or fluid joint
therewith.
It will be observed that in this form of construction when the raised concentric
portion of the drum is in contact with the bearing surface k of one of the heads of
the gate, the depressed concentric portion o of the drum is in contact with the

page_text: bearing surface of the other head of the gate, and that when the edge formed by
the intersection of the surface n with the surface p is in contact with the inclined
surface i of one of the heads of the gate, another edge forined by the intersection of
a portion n with the adjoining surface p, is in contact with one of the inclined
surfaces of the other head of the gate.
For the purpose of supplying propulsive force to rotate said drum in the form
shown in Fig. 11-14, I provide inlet ports qq, through the heads of the gates and
the adjoining wall of the ring, and outlet ports similarly situated on the opposite
sides of the gate heads, as shown in Fig. 13. The arrangement of these ports in the
gate-head is also clearly shown in Fig. 14. These ports are so arranged that when
the gate-heads are moved into operative position so as to constitute one of the walls
of the working chamber, the ports are opened, the inlet port being connected with
the chamber on one side of the gate-head and the outlet port being connected with
the chamber on the other side of the gate-head, and when the gate-head is forced
back into the cross-channel m so as to be forced out of operative position, the ports
will be shut. The inlet ports 7 of one head are alternated or staggered with
reference to the inlet ports q of the adjoining head, and the outlet ports r of one
head are similarly alternated or staggered with reference to the outlet ports of
the adjoining head. The result of this is that the intervening walls between one
series of ports will be exactly opposite the port openings of the next series. The
object of this is to prevent the uneven wear upon the face of the drum which would
result from having the ports opposite one another or in line with one another, and
the intervening walls opposite one another or in line with one another.
Instead of arranging the ports as shown in Figs. 11-14, they may be arranged as
shown in Fig. 15 and Fig. 16, that is to say, both the inlet and the outlet ports may
be made to pass through the shaft and drum. In Figs. 15 and 16 ss are the inlet
ports, t t are the outlet ports, u is the main inlet or supply channel, and is the
main outlet or discharge channel.
In operation, the parts being assembled as herein before described, and as shown in
Figs. 11-14, and steam or other force being admitted through the inlet ports, and
being confined between the opposite surfaces of the face plates, it fills said pockets
until at one end thereof it presses against the end of the gate with its bearing surface
bearing tightly against the surface of the drum and constituting one of the walls of
the said pocket or working chamber and can go no further in that direction, and in
the opposite direction it presses against the raised concentric portion n of the
surface of the drum, so that it can go no further in that direction except by revolving
the druin, which it consequently does. Meanwhile, the adjoining outlet port just in
advance of the inlet port already described, is shut off, and before the said outlet port
is opened the said inlet port is closed by the action of the rotation of said drum and
by the positive action of the next succeeding raised concentric portion n of the drum
upon the incline i of the gate-head containing the said inlet port. When the outlet
port is opened, the steain or other substance filling the chamber. escapes there-
through. This operation is repeated and the drum continues to revolve.
In the form shown in Figs. 15 and 16 the operation is substantially the same,
except that the ports are never shut off but the inlet ports are separated from the
outlet ports, except for a very brief interval during the revolution of the drum, by
the intervention of the gate-heads bearing upon the depressed concentric portions o of
the drum.
In the best form of my invention the rotary device is constructed in all its parts of
the same material throughout, such as cast iron or brass, and consequently when
steam or fluid of varying temperature is used, all parts of the machine will expand in
like degree, thereby insuring uniformn fit of the working parts relatively to one
another, which in a rapidly moving machine is a very valuable quality.
I wish to call attention to the fact that my rotary device takes its propelling power
simultaneously at opposing equidistant points of the circumference, so that there is
caused no sidewise strain or twist upon the shaft,

page_text: If my device is used as a steam motor, the exhaust can be condeused, if desired, or
a vacuum pump can be used.
It will be apparent that many of the details of my rotary device can be varied or
altered.
Both the shell and drum may revolve, or one may revolve and the other may be
stationary.
The number of gates and the number of concentric portions of the cam surface may
be varied according to circumstances.
Some of the advantages secured by my invention are simplicity of construction,
certainty and uniformity of operation, positive action of the reciprocating gates,
protection of the different parts from wear and injury resulting in part from the fact.
that the operating parts of the engine are all contained within the shell, an accurate
balancing of the device relieving it from side wise strain, reduction of friction, and
economy in the production of power.
Having now particularly described and ascertained the nature of my Inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a rotary device, the combination of two parts, one encircling the other, and
one adapted to revolve with reference to the other, one part being provided with a
cam surface having raised portions concentric with the axis of rotation, and depressed
portions concentric with said axis, and the other part having a surface concentric in
part or in whole with the axis of rotation, and a double-headed gate carried by one
of the parts and having bearing surfaces at or near both ends, and inclined portions
either on the cam surface or on the ends of the gate, the ends of the gate being in
contact with the cam surface all of the time so that the cam surface moves the gate
back and forth, and suitable inlet and outlet ports, substantially as shown and
described.
2. In a rotary device, the combination of two parts, one encircling the other, and
one adapted to revolve with reference to the other, one part being provided with a
cam surface having raised portions concentric with the axis of rotation, and depressed
portions concentric with said axis, said concentric portions being of substantially
equal arc and at an equal distance from one another, and inclined portions connecting
the concentric portions, and the other part having a surface in part or in whole
concentric with the axis of rotation, and two or more double-headed gates having
bearing surfaces at or near both ends which are in contact with the cam surface all
of the time so that the cam surface moves the gate back and forth, and suitable
inlet and outlet ports, substantially as shown and described.
3. In the rotary device, the combination of two parts, one encircling the other and
one adapted to revolve with reference to the other, one part being provided with a
cam surface having raised portions concentric with the axis of rotation, and depressed
portions concentric with said axis, and the other part having a surface concentric in
part or in whole with the axis of rotation and provided with interior slots to hold and
guide the gates, and double-headed curved gates sliding in said slots and having
bearing surfaces at or near both ends, and inclined portions either on the cam
surface or on the ends of the gates, the ends of the gates being in contact with the
cam surface all of the time so that the cam surface moves the gates back and forth,
and suitable inlet and outlet ports, substantially as shown and described.
4. In a rotary device, the combination of two parts, one encircling the other, one
adapted to revolve with reference to the other, and a double-headed curved gate
carried by one of the parts, and having bearing surfaces at or near both ends adapted
to be at all times in contact with the surface of the other part, and suitable inlet and
outlet ports, substantially as set forth.
5. In a rotary device, the combination of a drum and an encircling shell one
adapted to revolve with reference to the other, the shell being provided with an
interior cam surface having raised portions concentric with the axis of rotation and
depressed portions concentric with said axis, and inclined portions connecting said
R

page_text: concentric portions, and the drum having a surface in part or in whole concentric with
the axis of rotation and provided with uniformly curved slots to hold and guide the
gates, and double-headed uniformly curved gates sliding in said slots and having
bearing surfaces at or near both ends adapted to be in contact all the time with the
cam surface, and suitable inlet and outlet ports, substantially as set forth.
.
6. In a rotary device, the combinatlon of a drum and an encircling shell one
adapted to revolve with reference to the other, one being provided-with a suitable
cam surface and the other having a surface in part or in whole concentric with the
axis of rotation and provided with interior uniformly curved slots to hold and guide
the gates and double-headed uniformly curved gates sliding in said slots and having
bearing surfaces at or near both ends adapted to be in contact all the time with
different parts of the cam surface, substantially as set forth.
7. In a rotary device, the combination of the drum 2 having a surface concentric
with the axis of rotation, the shell 3, 3, 4 having a cam surface as described, the
curved gates 9 adapted to bear at all times at both ends against the cam surface, the
inlet ports, 16, 16, and the outlet ports 17, 17, substantially as set forth.
8. In a compound rotary device, the combination of a primary consisting of two
parts, one encircling the other, one adapted to revolve with reference to the other,
one being provided with a cam surface having raised portions concentric with the axis
of rotation and depressed portions concentric with said axis, said concentric portions
being of substantially equal are and at an equal distance from one another, and
inclined portions connecting the concentric portions, and the other part having a
surface in part or in whole concentric with the axis of rotation, and two or more
double-headed curved gates having bearing surfaces at or near both ends adapted to
be in contact with the cam surface all of the time so that the cam surface moves the
gates back and forth, and suitable inlet and outlet ports, and a secondary consisting
of similar parts similarly constructed and arranged, the inlet port of the secondary
being connected in line with the outlet port of the primary, substantially as shown
and described.
9. In a rotary device, the combination of two parts, one encircling the other, one
adapted to revolve with reference to the other, and a double-headed, curved gate
carried by one of the parts and having bearing surfaces at or near both ends adapted
to be at all times in contact with the surface of the other part, and suitable inlet and
outlet ports staggered with reference to one another, substantially as set forth.
1007
GEORGE BOHAN SHEPARD.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant..