CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1855

page_text: LETTERS PATENT to Christopher Jelinger Symons, of Hereford, in the
County of Hereford, Captain in the Bombay Army, for the Invention of
CERTAIN IMPROVEMENTS IN STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said Christopher Jelinger Symons
at the Office of the Commissioners of Patents, with his Petition, on the
28th June 1855...
I, CHRISTOPHER JELINGER SYMONS, do hereby declare the nature of the said
Invention for "CERTAIN. IMPROVEMENTS IN STEAM ENGINES" to be as follows:-
The Invention consists of novel methods or arrangements of machinery for
deriving propelling power from the action of steam in a cylinder, in some of
which the cylinder itself is caused to move in a vertical and in others in a
horizontal or inclined direction; the piston in either case being stationary. The
principal features relate to.the manner in which the piston is firmly maintained
in its position, with a view to obviate as much as possible friction caused by
its weight bearing on the lower part of the cylinder; also the means of moving.
the massive cylinder with. the least friction, combined with steadiness and,
security; the arrangements for applying connecting rods of great length in
proportion to the space occupied by the engine, and the methods of supplying
the cylinder with steam, and causing the steam to pass off to the condenser.
4

page_text: In one form of engine, constructed according to my Invention, the cylinder
is placed horizontally, and moves backwards and forwards while the piston
remains stationary.
The piston has two piston rods, placed one above? the other, and passing
through two stuffing boxes in the end or cover of the cylinder, and firmly fixed
to a block or support. The weight of the piston is thus supported. The
cylinder has two trunnions at the sides, on which are placed two large wheels,
which run upon horizontal rails and carry the weight of the cylinder. A
bracket or brackets-is-or-are-fixed-to-the-cylinder-cover, and the end of the
bracket is supported by a horizontal guide parallel to the axis of the cylinder.
From the end of this bracket the connecting rod or rods proceed to the crank
or cranks on the main shaft of the engine. The valves and valve box are
mounted on the cylinder, and the connections with the boiler and condenser
are made by means of pipes placed parallel to the axis of the cylinder, and
sliding in larger fixed pipes through stuffing boxes at their ends. The valves
may be worked by tappets, cams, or eccentrics: The cylinder may be guided
by other guides; while its weight is supported entirely or principally by the
wheels. This engine may be arranged in a vertical position in lieu of hori-
zontal, and the wheels, may then be dispensed with, and ordinary guides
employed, the connections with the boiler and condenser remaining as before.
The engine may also be placed -in-an inclined position if desired, and the
power may in either case be communicated directly to the main shaft, or
with the intervention of side levers or beams... The side levers or beams may
be,driven by studs on the cylinder entering slots in the side levers or beams,
while the other end or ends of the side levers or beams communicate the
the motion to the crank or cranks by a connecting rod. or rods. Two or
more of these engines acting upon cranks at angles to each other may be
employed, as is usual when employing other descriptions of engines for
propelling vessels. These engines may be made double acting or single
acting, that is to say, they may receive the steam at both ends alternately
or only at one end. In constructing single-acting engines with vertical
cylinders, I make the cylinder closed at the top and open at the bottom, and
I place it over a fixed inner cylinder, upon which it slides up and down
with the intervention of suitable packing. The inner cylinder is divided into
two compartments by a vertical partition, and is closed at the top by a valve
box and valve, which alternately puts the cylinder in communication with the
one compartment which is supplied with steam from the boiler, or with the
other compartment, which communicates with the condenser. The passage or
aperture which communicates with the cylinder is placed in the centre, so that

page_text: the steam in rushing into the cylinder may impinge with its full force against
the top end or cover of the cylinder, and thus act by its impinging force as well
as by its expansive force.
In applying these single-acting engines, I prefer to employ three or more
acting upon cranks at angles to each other, but in each case the number of
engines employed together may be varied, or they may be used singly if
required, and they may be placed in vertical, horizontal, or inclined positions,
and the power may be communicated directly to the crank shaft or through
the intervention of side levers or beams. When engines are made with con-
necting rods and cranks as above mentioned, they are adapted for producing
one revolution of the main shaft by a double stroke of the engine; but when a
greater speed is required, I employ an additional apparatus in lieu of the con-
necting rods and cranks, by which I obtain one revolution of the main shaft
for each single stroke of the engine. This is effected by causing the moving part
of the engine (whether cylinder or piston) to work in a guide and to be con-
nected to a band passing round two pulleys or drums whose circumference is
equal to the stroke of the engine. One of these drums drives an equal drum
running loose upon the main shaft, and which may be called A, by an open band
or bands, and another similar drum B, by means of two crossed bands. These
bands are not endless bands, but are wound upon the drums to which their ends
are fixed. They thus wind and unwind upon the drums without interfering with
each other. By this arrangement, the drums A and B receive an alternating
rotary motion, but always in contrary directions. Each of the drums A and
B carries a small sliding block or catch, which acts like the click or paul of a
ratchet wheel, upon a spiral cam, which acts in a similar manner to a ratchet
wheel having only one tooth. Thus, when the drum A is driving its cam, the
drum B is running in the contrary direction, and is producing no effect; but
as soon as the motion is reversed, the 'drum B drives its cam, and the drum A
runs back without producing any effect on the shaft. The shaft on which the
cams are fixed is thus made to revolve constantly in the same direction, and
to make a whole revolution for each single stroke of the engine.

page_text: "
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of June; in the year of our Lord
One thousand eight hundred and fifty-five, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give, and grant unto me, the said
Christopher Jelinger Symons, Her special license that I, the said Christopher
Jelinger Symons, my executors, administrators, and assigns, or such others as
I, the said Christopher Jelinger Symons, 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 Channel Islands, and Isle of Man, an Invention for
"CERTAIN IMPROVEMENTS IN STEAM ENGINES," upon the condition (amongst
others) that I, the said Christopher Jelinger Symons, my executors or
administrators, by an instrument in writing under my, or their, or one of
their hands and scals, 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 Christopher Jelinger. Symons, do hereby
declare the nature of the said Invention, and in what manner. the same is to
be performed, to be particularly described and ascertained, in and by the
following statement thereof, reference being had to the, accompanying Draw-
ings, and to the figures and letters marked thereon (that is to say): :-
In one form of, engine constructed according to my Invention, and which I
call a "truck engine," the cylinder is placed horizontally, and moves backwards
and forwards while the piston remains, stationary.
Figure 1, Sheet; is a view of this engine taken sideways, and explaining
its action; Figure 2-is a cross section of the same, taken vertically through
the steam chest A and passages B and C, as well as the concentric pipes D
and E, by one of which D steam is admitted from the boiler, and passes off
by the other pipe E to the condenser. In this section- are shown a pair of
large wheels F, F, which support the weight of the moving cylinder G with
all its attachments, as well as the substantial pieces H; II, which are cast with
the cylinder for the purpose of holding the trunnions I, I, on which the wheels
F, F, are fixed, leaving ample room in the openings J, J, for the connecting
rods to pass through close to the cylinder. The piston has two piston rods
K, K, placed one above the other, and passing through two stuffing boxes in
the end or cover of the cylinder, and, firmly fixed to a block or support L, as
shewn in Figure 1. Or, in lieu of the two piston rods, one deep flat piston'

page_text: rod of rectangular or elliptical or other similar. form may be used. The
weight of the piston, which admits of being made very shallow and light, is
thus supported. The cylinder has two trunnions, I, I, at the sides, on which
are placed the two large wheels F, F, which run upon horizontal rails M, M,
as shown in Figure 2,.. and carry the weight. of the cylinder. A bracket or
brackets N, Figure 1, is or are fixed to the extremity, of the cylinder G,
through which the connecting rods O pass, and the end of the bracket is
supported by a horizontal guide P, parallel to the axis of the cylinder. The
manner of connecting the end of the bracket N with the guide for the purpose
of causing the. connecting rod pin a to traverse steadily in both directions,
and likewise the contrivance for adjustment in case of wear, by means of a
wedge and an outside piece c to prevent the bracket from lifting, is shewn
in Figures 1 and 4. A horizontal section of the bracket, through the connect-
ing rod pin a, is shewn at Figure 5.
The horizontal wedge b is advanced by means of a vertical sliding piece d
which is advanced by a screw e. The bracket is prevented from rising by
means of the outside piece or clip c, which passes under the guide P, and is
adjusted by a screw and nut f, and secured. by other screws and nuts g,.g.
From the end of these brackets the connecting rod or rods O, Figure 1;
proceed through the openings J, J, between the wheels and cylinder, as
shown in Figure 2, to the crank or. cranks Q on the main..shaft R of the
engine, as seen in Figure 1. The valve S and valve box. A. are. mounted on
the cylinder, and the connections with the boiler and condenser are made by
means of pipes D and E, placed parallel to the axis of the cylinder, and sliding
in larger fixed pipes through stuffing boxes.at. their ends, as seen at D¹ in
Figure 1.
In
Figure 6 shows another arrangement of sliding pipes for connecting the
moving cylinder with the steam pipe and exhaust pipe. The pipe h is con-
nected by a socket i to the cylinder, and slides within the pipe j, which is jointed
or connected to the steam pipe or exhaust pipe by another socket k. The
pipe j has a stuffing box at the end, to prevent the escape of the steam.
this arrangement, the pressure of the steam has a tendency to lift the cylinder,
while the vacuum in the condenser has a tendency to draw down the cylinder.
This is prevented by the arrangement shewn in. Figure 7, in which the pipe: j
is closed at the upper end, and passes through a short pipe 7, having a stuffing
box. at each end, and connected with the cylinder by a socket i. The pipe j
is-perforated with several lateral-holes-at-the part-which is inclosed by the
pipe-
"
Figure 8. shows another arrangement of socket pipes, partly in section.

page_text: The pipe h is connected by a socket or joint i with the cylinder, and by the
socket m with the pipe j, which is connected by a socket at k with the .steam
or éxhaust pipe n. Figure 9 is a section of the end k of the pipe j...
The socket n has a cylindrical hole at each side; through. which passes the
cylindrical end.k of the pipe j, which has a shoulder o which bears.against one
side of the socket'; p is a flange, which is attached by screws to the closed end
of the pipe, which flange bears against the. other side of the socket. The
steam passes from the socket through perforations in the cylindrical end k of
the pipe. The pressure of the steam is thus balanced, and has no tendency to
force the pipe in either direction; friction is thus avoided: The joints m and i
are constructed in a similar manner..
" W
The Diagram, Figure 10, shews the positions of the pipes, corresponding to
the two extreme positions of the cylinder. One of these pipes is attached
to each side of the cylinder conveniently close to the steam chest, and they
communicate respectively with the boiler and condenser. When these socket
pipes are used, other guides will be fixed beneath the cylinder to retain it
steadily on the rails; independent of the guides applied for steadying the
brackets that.. carry the connecting rod pins. Should the steam be conveyed
by pipes, as in Figure 1, they will of themselves act as guides to steady thé
cylinder but other guides may be applied, while the weight of the cylinder is
supported entirely or principally by the wheels. The valves may be worked by
tappets, cams, or eccentrics.
Figure 3 is a plan of the steam passages and chest. This engine may be
arranged in a vertical position in lieu of a horizontal position; and the wheels
may then be dispensed with and ordinary guides employed, the connection
with the boiler and condenser remaining as before. Figure 11 is a horizontál
section of such an arrangement. The steam pipes D, E; act as guides on the
one side, while on the other side vertical guides TT, supported by suitable,
framework, are fitted to the cylinder G on the steam chest side, leaving
sufficient space for the vibration of the connecting rods O, O. The engine
may also be placed in an inclined position if desired, and the power may in
either case be communicated direct to the main shaft, or with the intervention
of side levers or beams... The side levers or beams may be driven by studs on
the cylinder entering slots in the side-levers.or beams, while the other end or
ends of the side levers or beams communicate- the motion to the crank or
cranks by a connecting rod or rods: Two or more of these engines acting
upon cranks at angles to each other may be employed, as is usual when
employing other descriptions of engines for propelling vessels. These engines
may be made double-acting or single-acting, that is to say, they may receive

page_text: the steam at both ends alternately, or only at one end. I also construct
single-acting engines with vertical cylinders, with the cylinder closed at the
top and open at the bottom, and I place it over a fixed inner cylinder; as seen
in Figure 12, upon which it slides up and down with the intervention of
suitable packing. The inner cylinder U has inserted within it a broad flat
steam pipe E, standing vertically in the centre, as seen in the plans, Figures 13
and 14, and secured by flanches and bolts to the double bottom 9. shewn in
plan in Figure 15, and in section in Figure 16. The upper end of this steam
pipe; round which the steam circulates on all sides, is covered in by a circular
plate r, shewn in Figures 12 and 14, which prevents the access of steam to
the working cylinder G otherwise than through the regular steam passage cut
in its centre. On the side next the boiler, or on the steam side of this broad
flat steam pipe, which is surrounded by steam for the purpose preventing
the inner cylinder from getting chilled by the external 'air, is placed the
valve Sand steam passages, which are clearly shewn in the section, Figure 12';
and it will be seen that the upper part of the broad flat steam pipe conveys the
elastic force to the outer or working cylinder G, and the lower part of the
same on the 'valve being shifted conveys the steam either to the condenser or
the open air. The passage or aperture which communicates with the cylinder
is placed in the centre, so that the steam on rushing into the cylinder may
impinge with its full force against the top end or cover of the cylinder," and
thus act by its impinging force as well as by its expansive force. I call
these engines "impinging engines" to distinguish them from the others. >
By a somewhat more complicated method, I construct cylinders on the
same principle, with the steam passages in a horizontal plate, and the valve
moving in a horizontal direction, as shewn in section in Figure 17, the valve S
moving steam-tight between two flat 'discs s, t, in which the steam passages
are cut. This valve, which is entirely open at 'the back or upper side, works
on the equilibrium principle, and is thus relieved from the pressure of the
steam. The upper side is furnished with a soft packing on its outer edge
next the steam, such as hemp, vulcanized india-rubber, or other packing, which
will last for a great length of time, as it has not to pass over any openings,
but merely moves up to the edges of the steam passage without passing over
them. This 'equilibrium valve will receive its motion from suitable levers and
rods attached to both sides thereof, working in the open spaces shewn at u, u,
in Figure 18, through which the steam passes upwards and surrounds the
valve ready to enter the cylinder:: The valve-in-Figure-12-moving vertically,
can be relieved of the steam pressure by fixing a plate across the back for it-
to rest against, having a soft packing, as in the other valve. There are two

page_text: methods of applying the packing ring in these engines; the one shewn in
Figure 12, and applied to the outer or working cylinder, and the other is
attached to the inner cylinder and remains stationary, as in Figure 17. The
former, though not so compact, is preferable, because no external air can enter
the working or outer, cylinder to chill it or alter its temperature. In Figure 17
there is a narrow space left for clearance to avoid friction, by the two large
surfaces moving constantly in contact with each other, and into this space
the external air would enter as the working cylinder descended; but as the
inner cylinder is always full of steam when the engine is in motion, the
air, would readily become heated as it entered this narrow space, and
the working cylinder would scarcely be affected by it. The plan of the
outer packing ring in Figure 12.admits of the working cylinders being
lubricated in the most perfect manner, as oil poured through the cylinder
cover would hang and circulate, round about the inner cylinder in the narrow
space left for clearance, and the packing ring (which in this engine repre-
sents the piston itself, and need be but very shallow,) would always be well
lubricated, thus reducing the friction of the working cylinder to the smallest
possible degree. On the outside, ring, bolted to the cylinder, for the purpose
of holding the packing ring, will be observed the piece V, in which the con-
necting rod pin is fixed and bolted firmly both to this ring and the cylinder;
as in Figure 19. Guides supported by suitable framework will be attached
to these cylinders to steady them in their action, whatever their working
position may be.
In applying these single-acting engines, I prefer to employ three or more
acting upon cranks at angles to each other, as indicated by, the Diagram,
Figure 20.; but in each case, the number of engines employed together may
be varied, or they may be used singly if required, and-they may be placed in-
vertical, horizontal, or inclined positions, and the power may be communicated
directly to the crank shaft, or, through the intervention of side levers or beams.
When engines are made with connecting rods and cranks, as above men-
tioned, they are adapted for making one revolution of the main shaft by a
double stroke of the engine; but when a greater speed is required, I employ
an additional apparatus in lieu of the connecting rods and cranks, by which I
obtain one revolution of the main shaft for each single stroke of the engine.
This is effected by causing the moving part of the engine (whether cylinder s
or piston) to work in a guide, and to be connected to a band passing round
two pulleys or drums A and B, whose circumference is equal to the stroke of
the engine, as seen by reference to the side view, Figure 21. A section or end
view of the guide N with the end of the piston rod G is shewn in Figure 22.
"
.

page_text: Figure 23 is a plan of the engine, which I call a "band engine." One of
these drums A drives an equal drum C, running loose upon the main shaft D
by an endless band E,: similar to that F, to which the piston rod G is attached';
and the same drum A which drives the loose drum, marked C, also from its
opposite end drives another loose drum. H, but causes it to move in the oppo-
site direction by means of two distinct unfolding bands I, J, whose action is
precisely similar to that of a cross band. These bands are not endless bands,
but are wound upon the drums to which their ends are fixed, as seen in
Figures 24 and 25. They thus wind and unwind upon the drums without
interfering with each other. In Figure 24 the drums are cut in the form of
a cam to allow the band to sink into them; and in Figure 25 the drums are
made, in an eccentric form, and the ends of the bands are gradually sloped off,
so as to present an even folding surface; but by the application of such a
band as shewn in Figure 26 (being the same as that used in Figure 23) it
is neither necessary to alter the circular form of the: drum or to slope off the
ends. of, the bands; as: this band' will fold itself to the full extent required
without any overlap taking place.
.
From its peculiar form it will be requisite that such a band be of metallic
construction, such; as iron or other wire; but the endless bands, and likewise
the plain unfolding bands, may be made either of leather, gutta percha, or
other suitable material, or they may. be wholly or partially made of iron
or other wire. Whether bands or chains be used, studs will be fixed in the
drums, and will enter holes in the endless bands. to prevent the possibility of
their slipping. By this arrangement, the. drums C and H receive an alter-
nating rotary motion, but always in contrary directions. Each of the drums
C and H carries a small sliding block or catch K, which acts like the click or
paul of a ratchet wheel, upon a spiral cam L, which acts in a similar manner
to a ratchet wheel having only one tooth. The one-toothed cam L, which is
keyed on to the main shaft D, and the click or paul K which acts upon it, are
shewn, in side view, attached to the drum in Figure 21. The click or paul
is inclosed in a box or case, the upper part of which contains either a spiral
spring or one of vulcanized india-rubber M, to cause it to fall with rapidity into
its seat. Thus, when the drum C is driving its' cam, the drum H is running
in the contrary direction, and is producing no effect; but as soon as the motion
is, reversed, the druin H drives its cam, and the drum C runs back without
producing any effect on the shaft. The shaft on which the cams are fixed is
thus made to revolve, constantly in the same direction, and to make a whole
revolution for each single stroke of the engine: The peculiar features of this
engine, are, that it is quiet in its action, that it has no dead point whatever, but on

page_text: the contrary, the piston rod pulls up dead at the end of the stroke, and starts
again at the most favorable point, that by the manner in which the piston rod is
held firmly down in the guide 'N as it traverses backwards and forwards, the
endless or main driving band F, to which it is firmly bolted, prevents it from
overrunning itself, as it is clear the band cannot lift the piston rod, nor can the
piston rod travel beyond the length of stroke without breaking the band itself,
the length of -stroke completely governing the distance that the two, outside
shafts must be from each other from their respective' centres: An additional
space; however, over and above the length of stroke is necessary in order to
have sufficient space for bolting the band' firmly. to the piston rod head. r 'As an
additional precaution against the piston "overrunning itself, there may be fixed
on both sides of the piston, springs that will alternately come in contact with
the inside of the cylinder cover and cylinder bottom, by which the thrust * will
be much eased, particularly when the piston is also well cushioned, by giving
the valve sufficient-lead; or these springs or aspad of india-rubber may be
attached to the cylinder cover and bottom in lieu of being attached to the
piston; or the cushions, pads, or springs may be placed at each end of the guide
on which the piston rod head works
Figure 27, Sheet II is a longitudinal 'section of an apparatus to be applied
to the band engine for checking and quickly reversing, the notion of the pistón
at each end of the stroke! The piston rod is prolonged and carried through
a stuffing box in the end of the cylinder of the engine, and this prolonged piston
rod carries a piston D, which enters two short cylinders A, A, at the two ends-
of its stroke. These cylinders are firmly fixed to the framing or foundation of
the engine. The air in these cylinders having, no outlet is compressed by the
piston; whose motion is thus quickly arrested: The compressed air by its
elasticity assists in starting the; piston again in the opposite direction. If-a
portion of the air should escape round the piston or through the stuffing box'a,
through which the piston rod passes, the consequence would be, that a partial
vacuum-would be produced in the cylinder, which would check tlie motion of
the piston. To prevent this effect, an aperture with a-valve b'opening inwards
is placed at the end of the cylinder. This valve admits air whenever the
pressure in the cylinder falls: below that of the atmosplierë......
...Figure 28; Sheet II: ista side view, 'partly in section, and Figure 28 bis is
a horizontal section, of an apparatus for-checking the motion of the piston at
the end of its stroke; which apparatus I term a "break." This apparatus
consists of a strong iron framework in two parts A and B, firmly bolted
together, with a broad circular groove C between them. "D is a solid iron
block which works in the groove C, and has two trunnions a, a, by which it'is
"

page_text: connected to the forked connecting rod E, which is jointed to the piston rod F.
This piston rod may pass out at the back of the cylinder of the engine shewn
in Figures 21 and 23. The block D travels backwards and forwards in the
groove C from d to d, stopping at those points known as dead points, when
the piston alternately reaches the ends of its stroke. The head of the piston
rod M. has a flat cross piece attached to it, which runs in a slide n, n, in order
to preserve its direction in a straight. line. In Figure 28 the piston has
carried the block D. to one end of the stroke, and has forced up a spring o
which is fixed above it, and which is. pressing strongly on the block, in order
to cause. it with the end of the connecting rod to fall immediately when the
direction of the piston is reversed by the action of the steam. Behind, and
secured to the block at g, is a spring of vulcanized india-rubber, which. tends
to steady it while reciprocating within the groove, and also, by yielding to the
pull or push of the piston. at the return of the stroke, enables the spring o
above the block to instantaneously force it below.the dead point, in which
action also the weight of the connecting rod will considerably assist: Instead
of the block D a. roller or wheel may be employed to diminish the friction,
and the groove C may be of elliptical or other suitable curvilinear form in lieu
of being circular.
.
Figures 35 and 36, Sheet II., are side views of another apparatus for
checking the motion of the piston at the end of its stroke. The dotted line
represents the course of the piston rod, the head of, which works in a guide
and carries a-pin D, which enters a slot in a lever C, which turns upon bearings
or trunnions at c. This lever carries two short strong arms, to which are
jointed the links H, H, whose ends are connected by other links I, I, with, the
pin D. ee, are two strong springs attached to the lower part of the lever C.
Figure 37-is a plan of the lower part of the lever C. When the piston is at
half-stroke the links H, I, assume the position.shewn in Figure 36, but when
the piston reaches the end of its stroke the links H, I, are brought into a
straight line, and the motion of the piston is thus arrested at the right point;
at the same time the: springs e, e, are compressed by the links H, H, coming
in contact with them. These springs immediately expand again, and force-the
links apart as the-piston commences its return stroke:
d
The unfolding bands, by which I reverse the motion of the drums, admit, of
an engine being constructed. of, very, great power on this principle, which could
not be done if a cross band was used, as..the stronger. the band the greater
would be the difficulty caused by friction in the edges grinding-heavily
against each other I likewise construct engines on this principle with two
toothed-wheels-driving each other-in-opposite directions- in lieu of unfolding.

page_text: bands. When I construct engines on this principle with the length of stroke
only equal to half the circumference of the drum, the- cam would have two
teeth, and the disposition of the drums would be entirely altered; the one,
which in Figure 21, Sheet I., stands farthest from the cylinder O, would change
places with the loose drums and main shaft, which would then be placed farthest
from the cylinder." In such engines I should use the unfolding bands in
preference to any other contrivance for reversing the drums. When this band
engine is intended to work both ways without the application of bevil wheels
and a clutch to reverse the motion, the cam L, shown in Figures 21 and 23, is
made double, as shewn at L, L', in Figures 29 and 30, Sheet I., and two clicks
or pauls are applied to the loose drums. .
Figure 31 is a section through the double cam L, L, and pauls K, K,
which drive it. Figure 32 is an end section through one of the pauls K (and of
which Figure 33 is the plan), showing the 'contrivance with which the engine
is reversed when stopped; wherein it will be seen that when one paul is driving
the other is out of gear, and raised clearly out of its seat, so as to enable the
tooth of the cam which is not in action to pass it without coming in-contact.
When the paul; represented by K in the several sections, is raised by means of
the rack wheel P and lever Q attached to it, the other paul K is down in its
seat, ready to drive the tooth of the cam Lin the direction of the arrow... The
lever Qattached to the rack wheel of the paul, which is inactive, is held
steadily down by a ring, which loops on the notch observed on the lever Q,
while the other lever Qattached to the toothed wheel P plays: backwards
and forwards as the paul rises and falls.
Figure 34 is a section, shewing a construction of slide valve S, adapted for
the truck engine and the band engine, and so arranged that the proper parts
are opened without the aid of levers. On the valve spindle v are attached
two adjustable rings or studs w, w, which come in contact with the abutting
piece x, fixed to the pedestal into which the piston rods are secured, and by
the cylinder itself moving, the studs cause the valve S to move-in the required
direction. In the band engine there is a long slotted rod attached to one side
of the piston rod head, and on the end of the valve spindle there is a stud or
button working freely in the slotted rod, which causes the valve to move
precisely in the same manner as in the truck engine.
These engines may all be worked on the expansion principle by cutting
off the steam at any required part of the stroke, and the weight of the
moving parts of the truck engines and. impinging engines facilitates the
carrying out of the expansion principle, and also causes them to work with
greater regularity as the weight of the moving parts acts, in a similar manner

page_text: to a fly wheel. The impinging engines are single-acting, but when employed
with a condenser the pressure of the atmosphere acts in the return stroke.
When placed upright the weight of the cylinder also acts in the return. By
proportioning the pressure of steam and the degree of expansion to the
vacuum in the condenser, these engines may be made to produce the same
amount of power on the crank in both strokes.
Having now described the nature of my Invention, and in what manner
the same is to be performed, I wish it to be understood that I do not
claim generally the constructing steam engines with fixed pistons and move-
able cylinders, nor do I confine myself to the precise details herein-before
described, as the same may be varied, provided the peculiar character of each
part of my Invention be retained; but what I claim is,―
Firstly, the constructing steam engines with a fixed piston and a moveable
horizontal cylinder, supported on a pair of wheels, and having attached to it a
bracket or brackets, guided by a guide or guides, and carrying a connecting rod
or rods, which communicate the motion to a crank or cranks, as herein-before
described under the name of "truck engines."
Secondly, the mode herein-before described of supporting the piston of the
"truck engine" by means of two piston rods, or one deep flat piston rod firmly
fixed to a pillar or support.
Thirdly, the constructing truck engines and engines with vertical or inclined
moveable cylinders and fixed pistons with sliding or jointed pipes for the
entrance and exit of the steam, as herein-before described.
Fourthly, the constructing single-acting engines as herein-before described
under the name of "impinging engines," having a moveable cylinder in-
closing and working upon an inner fixed cylinder, which is filled with steam,
and provided with a suitable valve or valves for the entrance and exit of the
steam which acts upon the outer cylinder.
Fifthly, the constructing engines as herein-before described under the name
of "band engines."
In witness whereof, I, the said Christopher Jelinger Symons, have
hereunto set my hand and seal, this Sixth day of December, in the
year of our Lord One thousand eight hundred and fifty-five.
CHRISTOPHER JELINGER SYMONS. (1