IMPROVEMENTS IN ROTARY ENGINES AND PUMPS
Year: 1877

page_text: LETTERS PATENT to Cyrus Avery, of Little Cross Street, Islington, in the
County of Middlesex, Engineer, for the Invention of. "IMPROVEMENTS IN
ROTARY ENGINES AND PUMPS."
Sealed the 4th January 1878, and dated the 11th July 1877.
PROVISIONAL SPECIFICATION left by the said Cyrus Avery at the Office
of the Commissioners of Patents on the 11th July 1877.
CYRUS AVERY, of Little Cross Street, Islington, in the County of Middlesex,.
Engineer. "IMPROVEMENTS IN ROTARY ENGINES AND PUMPS."
My Invention relates to rotary engines to be driven by steam, air, water, or other
fluid, and it has reference to that class in which the fluid is caused to act upon a
piston concentric with the bore or internal periphery of the cylinder, and of less
diameter than the same, except at one point where it is provided with a projection
in contact with the said bore or internal periphery and forming the acting surface
of the piston, the fluid being admitted to the cylinder on one side of a partition
(which is moveable for the passage of the projection of the piston) and exhausted
from the other side after having done its duty in the cylinder.
My Invention consists of various improvements in rotary engines of this description,
having for their object, simplifying their construction, whilst at the same time
increasing their efficiency by utilizing to the maximum degree admissible the power
of the motive fluid expended in driving the engine.
In carrying out my Invention in order to effect this object, I construct the movable
partition (which slides across the annular cylinder chamber in a plane parallel with
that of the main shaft on which the piston is mounted) of a recessed form at its
centre, so that the projection (herein-after termed the piston) will pass when the
partition is in its intermediate position, whilst, when it is in either of two extremo
The
positions, the solid portion will separate the two ports the one from the other.
partition is actuated at the requisite periods by means of a cam fast on the main
shaft, and having two circumferential grooves in its periphery, which, for a portion
of their length, are spiral or inclined in a right and left hand direction respectively.
so as to intersect each other. In these grooves is fitted a jointed or flexible
elongated button or worm to which the moveable partition is attached by suitable

page_text: connections, and which button or worm is traversed first by one groove and then by
the continued revolution of the cam, by the return groove, so as to impart the
to-and-fro reciprocating motion to the partition with the least amount of friction
and concussion practicable.
The connection of the worm with the moveable partition may be arranged in the
following manner-For example, the worm may be attached to a cross head sliding
along guides and connected by a rod to the moveable partition. Or the cross head
and guides may be dispensed with, and the head of the connecting rod of the
moveable partition to which the worm is attached may have pivotted thereto two
segments (one on each side) having one or more teeth or indentations capable of
engaging with a similar number of recesses or teeth formed in or on corresponding
side guide bars, so that as the rod is reciprocated, the segments will oscillate upon
their pivots and in contact with the guide bars, and the parallelism of the motion
will thus be ensured. Or in lieu of the preceding arrangements, any equivalent
modification thereof may be employed for transmitting a parallel motion with a
minimum amount of friction.
The engine operates in the following manner:-Steam, for example, is admitted
through a rotary valve mounted on the main shaft, and thence through the cylinder
head to the rear of the piston, the partition being, say, for example, in its inner
extreme position, closing the passage between the two ports, and the worm being
in the left-hand groove of the cam. Motion is thus imparted to the piston by the
steam acting thereon, which motion is transmitted through the shaft to the cam and
the valve, the latter cutting off the steam at any required period, and the former
(the cam) moving the partition at the requisite intervals. By the time the piston
has arrived at the partition, the steam will have been exhausted and the partition
will have been moved outwards so as to bring its recess opposite the piston to admit
of its unobstructed passage, the worm being then in the right-hand groove of the
cam, after which the outward motion of the partition is continued so as to imme-
diately bring its inner solid portion into the position for separating the ports when
a fresh supply of steam is admitted behind the piston. When the piston again
arrives at the place of the partition, the latter will have been moved inwards for
the passage of the piston, the worm being then situate in the left-hand groove of
the cam, and by the continued motion of the piston and consequently of the worm,
the inward motion of the partition will be prolonged until its outer extreme portion
is moved into the position for separating the ports, when the former operations will
be repeated, and so on in succession.
The worm is made in parts, fitted together by joints, or otherwise constructed in
such a manner as to admit of its yielding to the sinuosities of the cam grooves, so
that when it has been acted upon by one groove during one revolution of the cam,
on the point of intersection of the two grooves being reached, it will readily
yield to the other groove which then passes over it, and so on in succession, both
grooves traversing alternately over the worm and transmitting the requisite move-
ments through it to the moveable partition.
The valve may be constructed in the form of a segment of a ring with its
two ends connected by a spring so as to be self adjusting under variations of
temperature.
If desired, two cylinders may be combined in one engine, their pistons being
mounted on one and the same shaft, and the valve mechanism operated by a single
cam common to the two.
The central shaft may be provided with driving pullies or other ordinary appliances
for transmitting the motion or power.
It is obvious that by driving the apparatus by a prime mover, it may be utilized
as a pump without any, or with but slight modifications in its details.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Cyrus Avery in the Great Seal Patent Office on the 10th January
1878.
CYRUS AVERY, of Little Cross Street, Islington, in the County of Middlesex.
"IMPROVEMENTS IN ROTARY ENGINES AND PUMPS."
My said Invention relates to rotary engines to be driven by steam, air, water, or
other fluid, and it has reference to that class in which the fluid is caused to act upon
a piston concentric with the bore or internal periphery of the cylinder, and of less
diameter than the same, except at one point, where it is provided with a projection
in contact with the said bore or internal periphery, and forming the acting surface
of the piston, the fluid being admitted to the cylinder on one side of a partition
(which is movable for the passage of the projection of the piston), and exhausted
from the other side after having done its duty in the cylinder.
My Invention consists of various improvements in rotary engines of this descrip-
tion, having for their object simplifying their construction, whilst at the same time
increasing their efficiency by utilising to the maximum degree admissible the power
of the motive fluid expended in driving the engine.
In carrying out my said Invention in order to effect this object I construct the
movable partition (which slides across the annular cylinder chamber in a plane
parallel with that of the main shaft on which the piston is mounted) of a recessed
form at its centre, so that the projection (hereinafter termed the piston) will pass
when the partition is in its intermediate position, whilst when it is in either of two
extreme positions the solid portion will separate the two ports, the one from the
other. The partition is actuated at the requisite periods by 'means of a double cam
fast on the main shaft, and having two circumferential grooves in its periphery
which for a portion of their length constituting the cams proper are spiral or
inclined in a right and left hand direction respectively so as to intersect each other.
In these grooves is fitted a jointed or flexible elongated button or worm, to which
the movable partition is attached by suitable connections, and which button or
worm is traversed first by one groove and then by the continued revolution of the
cam by the return groove so as to impart the to-and-fro reciprocating motion to the
partition with the least amount of friction and concussion practicable, or the con-
verse arrangement may be adopted, the button or worm being grooved, and the cam
guides consisting of projections which are clipped or embraced by the said button or
worn.
My said Invention is also applicable to pumps of a like description.
And in order that iny said Invention may be fully understood I shall now proceed
more particularly to describe the same, and for that purpose shall refer to the several
Figures on the annexed sheet of Drawings, the same letters of reference indicating
corresponding parts in all the Figures.
Figure 1 of my Drawings represents a longitudinal sectional elevation taken along
the line 1, 2, Figure 2, of an engine constructed according to my said Invention;
Figure 2 is a transverse sectional elevation of the same taken along the line 3, 4,
Figure 1.
Figure 3 represents a detail plan of the button or worm, and the moveable
partition.
Figures 4 and 5 are views similar to Figure 1 of a portion of the engine, but
shewing different relative positions of the parts; and Figure 6 is a detail of the
piston.
Figure 7 is an under plan view illustrating a modification of the cam wheel and
worm, and Figure 8 is a detail of the worm.
Figure 9 is a sectional view illustrating another modification of cam and worm.
A is the cylinder made in two parts A1, A2, one of which, videlicet, the part A', forins
a portion of the supporting frame of the engine, whilst the other part A³ is attached
--
1.4.

page_text: The
to the part A¹ by bolts and nuts a. B is the annular chamber of the cylinder, in
which is fitted and works a projection C, from the main piston body C¹, mounted
fast on the shaft D. This projection, which constitutes the piston proper, consists
of a body b, carrying packing plates c, c, which are maintained apart so as to be in
contact with the sides of the annular chamber B by means of springs d, d.
main piston body C is also maintained in contact with the face of the part A² of
the cylinder, against which it works by means of springs d¹ and a packing ring d².
The shaft D is mounted (concentric with the annular chamber B) in bearings e, e¹,
the one being carried by the head E constituting a portion of the supporting frame
of the engine; and the other formed in an attachment E¹ to the part A² of the
cylinder. On the shaft D is secured, in addition to the piston body C¹, a rotary
valve F for regulating the supply of steam (for example) to the annular chamber B,
and also a cam wheel G for actuating the movable partition H, which forms the
abutment to receive the pressure of the steam when the same is acting upon the
piston. The valve F may be constructed and arranged in various ways. In the
example illustrated in the Drawings it consists of a ring f carried upon arm f¹ from
a boss f, fast upon the shaft D. The steam introduced by the passage I enters the
interior of the ring, and when an opening g formed in the latter is by the rotary
motion of the shaft D brought opposite to the port I, the steam passes into the
annular chamber B, the supply to the chamber being again cut off as soon as the
opening has passed the port I'. The ring f may be removed and another having
an opening g of a different length substituted when it is required to vary the degree
of expansion.
The cam wheel G, movable partition H, and their connections, which together
form the essential feature of my Invention, are constructed and arranged in the
following mauner,-
Referring to the partition H a sheath K is provided, projecting from opposite
sides of the cylinder in a plane parallel with the shaft D, within which sheath and
across the annular chamber B the partition H slides. The partition consists of a
plate recessed or cut away at its centre at h so as to provide space for the passage
of the piston C when the partition is in a position intermediate between two
extreme points, the end portions or leaves h¹, h², forming divisions or abutments
separating the steam port I from the exhaust port 12 when the partition is in the
respective extreme positions. The plate is fast upon a sliding rod or spindle L, to
which the requisite reciprocating motion is imparted by means of the cam wheel G,
through the intervention of a jointed or flexible elongated button or worm M
working in or on the cams of the wheel G, to which button or worm the rod or
spindle L is attached.
The cam wheel G is formed or fitted in or on its periphery, with two circum-
ferential guideways G², G², for the button or worm M, which guideways for a por-
tion of their length are spiral or inclined in a right and left hand direction
respectively, as shewn at G3, G4, so as to intersect each other, such spiral or inclined
portions forming the cams proper. The guideways G1, G2, may be either raised as
shewn in Figure 1, or sunk, as indicated in the modifications, Figures 7 and 9, the
button or worm being made of a counterpart form so as to work on or in the guide-
way, as the case may be. In the arrangement shewn in Figures 1 and 2 the button
or worm consists of two clips i, i, which embrace the cam, and are pivotted at 1, 1,
so as to be free to turn to a cross head k, which is jointed at 2 to the rod or spindle
L. The pivots 1, 1, carry rollers 1, l, which are adapted to guides m, m, supported
by the heads E, E², of a casing enclosing the cam wheel G, and to the head E³ of
which one end of the sheath K is secured, the said guides m, m, and rollers 1, 1,
insuring the rectilineal motion of the rod or spindle L, under the action of the
In the modification illustrated by Figures 7 and 8, in which grooved cams
are employed, the worm is composed of jointed links i, i, pivotted to the cross head
l, which is formed with eyes l, l, adapted to slide along guide rods m, m, carried
by the frame, whereby the parallelism of the motion of the spindle L is secured.
cams.

page_text: The modification illustrated in Figure 9 is simply the converse of the arrange-
ment of cam and button or worm shown in Figures 1 and 2, and will be understood
without further description.
If desired, in lieu of the arrangements of cross head and guides, herein-before
described, any equivalent modification thereof may be employed for transmitting a
parallel motion with a minimum amount of friction, as for example the head of the
rod or spindle L may have pivotted thereto two segments (one on each side), having
one or more teeth or indentations capable of engaging with a similar number of
recesses or teeth formed in or on corresponding side guide bars, so that as the rod is
reciprocated the segments will oscillate upon their pivots and in contact with the
guide bars, and the parallelism of the motion will thus be ensured.
-
The improved engine operates in the following manner :-Steam being introduced
through the passage I into the valve F, the latter is if necessary moved by turning
the shaft D by hand, so as to bring the opening g opposite the port 11, the piston
being then in the position indicated by dotted lines in Figure 2, and the partition
H, say in its extreme position with the leaf h³ closing the passage between the ports
11 and 12, and the worm M engaging with the left-hand cam G. Steam is thus
admitted through the port I' into the annular chamber B behind the piston C,
whereby the latter is moved in the direction of the arrow turning the shaft D,
which carries the valve F and the cam wheel G with it, the steam gradually
expanding as the piston advances. In the position in which the piston is represented
by the full lines in Figure 2, the worm and the cams will be in the relative position
indicated in Figure 1. When the piston arrives at the partition 'the steam will be
free to escape through the exhaust port 12 and the partition will have been moved
outwards into the position represented in Figure 4, bringing the recess h opposite
the piston to admit of its unobstructed passage, the button or worm M having been
moved under the action of the inclined portion G³ of the cams of the cam wheel
into the intermediate or central position shewn in that Figure.
By the continued motion of the cam wheel the worm will be carried on to the
right-hand cam G², as represented in Figure 5, thereby moving the partition H out-
wards, and bringing its leaf h' into position for separating the ports. A fresh
supply of steam is then admitted behind the piston by the opening g of the valve
being by the motion of the shaft D brought opposite the port I¹, and another
revolution is imparted to the piston. When the piston again arrives at the place of
the partition the latter will have been moved inwards for the passage of the piston,
the worm being then in its intermediate position on the inclined portion G, on its
way to the left-hand cam G¹, and by the continued motion of the piston and conse-
quently of the cam wheel, the worm will be brought on to the left-hand cam, and
the leaf h² of the partition will thus be moved into the position shewn in Figure 1
for separating the ports, when the former operations will be repeated, and so on in
succession.
The engine may be fitted with a governor and throttle valve for regulating the
supply of steam to the valve F, and also be provided with all other facilities usual
in steam engines, as for example, with pulleys, coupling, toothed gearing, or other
devices on the shaft D for transmitting the motion of the engine to machinery to
be driven, and with means for lubricating the bearings of the shaft. I have shewn
in Figure 1 of my Drawings an arrangement of lubricator which has been found
convenient in practice. It consists of a cup o into which the oil, for example, is
supplied, having a passage p leading into a chamber or reservoir q, whence the oil
passes through a passage r to the bearing to be lubricated, the ingress by the passage
p and the egress by the passager, being regulated by means of a valve 8 operated
by the aid of a handle t. Any other suitable arrangement of lubricator may
however be employed in substitution for that herein-before described and illustrated
in my Drawing.
If desired two cylinders may be combined in one engine, their pistons being
mounted on one and the same shaft and the valve mechanism operated by a single
cam wheel common to the two.

page_text: It is obvious that by driving the apparatus by a prime mover it may be utilized
as a pump without any or with but slight modifications in its details.
Having now described and particularly ascertained the nature of my said Inven-
tion and the manner in which the same is, or may be, used or carried into effect, I
would observe in conclusion, that what I consider to be novel and original and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,―
First. The application and use to and in rotary engines and pumps of the
description herein referred to of a duplex or recessed movable partition, arranged
and actuated so as to operate substantially in the manner and for the purpose
berein-before described.
Secondly. The employment of a duplex intersecting cam and a jointed or flexible
button or worm for actuating the movable partition, when the said parts are
arranged so as to operate substantially in the manner herein-before described.
Thirdly. The combination in a rotary engine or pump of a duplex or recessed
movable partition, and a duplex intersecting cam and jointed or flexible button or
worm for actuating the said partition, the whole constructed and arranged so as to
operate substantially in the manner and for the purpose herein-before described, and
as illustrated by my Drawings.
In witness whereof, I, the said Cyrus Avery, have to this my Specification set
my hand and seal, this Fifth day of January, One thousand eight hundred
and seventy-eight.