CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF STEAM ENGINES, AND IN THE APPLICATION OF STEAM ENGINES TO PROPELLING SHIPS AND OTHER VESSELS
Year: 1840

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
SEAWARD, of the Canal Iron Works, Poplar, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Seventeenth day of March, in the third year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Samuel
Seaward, Her especial licence, full power, sole privilege, and authority, that I,
the said Samuel Seaward, my exors, adiñors, and assigns, or such others as
I, the said Samuel Seaward, my exors, adiñors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, and
also in all Her said Majesty's Colonies and Plantations abroad, my Invention of
"CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF STEAM ENGINES, AND IN THE
APPLICATION OF STEAM ENGINES TO PROPELLING SHIPS AND OTHER VESSELS;" in
which said Letters Patent is contained a proviso, that I, the said Samuel
Seaward, shall cause a particular description of the nature of my said Invention,
and in what manner the same is to be performed, to be inrolled in Her said
Majesty's High Court of Chancery within six calendar months next and imme-
diately after the date of the said in part recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that, in pursuance of the said proviso, I, the said
Samuel Seaward, do hereby declare that my said invented Improvements are
Six in number, and that the nature thereof, and the manner in which the

page_text: same are to be performed, are fully specified and set forth in the following
description thereof, reference being had to the several Drawings hereunto
annexed, that is to say :-
The first of my said improvements consists in attaching to the piston of
the steam cylinder two arms which project through the sides of the cylinder,
and work up and down therein through steam and air-tight grooves, and in
conveying by means of a connecting rod attached or jointed to the said arms
the motion of the piston directly to the beam or cranks of an engine, without
the intervention, as usual, of a piston rod and parallel motion, or any similar
contrivance.
Figures 1 and 2 are front and side elevations of the cylinder, and some other
parts of a steam engine on this improved plan of construction, in which the
power is communicated from the piston to cranks. Figures 3 and 4* are cross
sections of the cylinder.
Figure 5 is a vertical section of the cylinder and piston, and Figure 7 an
enlarged section, shewing, more distinctly than is done in the other Figures, the
construction of the grooves, and the manner in which the arms of the piston
are made to move up and down therein without any escape of steam or admis-
sion of air taking place. Figure 6ª is a side elevation of part of an engine,
in which the power is communicated from the piston to a beam; A in all the
figures is the steam cylinder; Z, Z, are the side grooves, which do not extend
the whole way from top to bottom, but are of a length only equal to the length
of stroke of the piston and one of the sliding blocks M, herein-after described.
These grooves s should coincide exactly with a straight line drawn across the centre
of the cylinder, and their faces should be planed or wrought perfectly with the
axis of the cylinder; Q, Q, are flanges which form external faces to the grooves
Z, Z, and which are cast with the cylinder; B is the piston, C, C, the arms of
the piston, which project through the sides of the cylinder, and work up and down
in the grooves Z, Z; M, M, are two oblong sliding blocks (shown separately
in Figure 8) with circular apertures in the centre, which are passed over the
arms C, C, and fit into the grooves Z, Z, the circular apertures and external
faces of the blocks being all planed and ground true, so that by the exact
fitting of the arms to the circular apertures, and of the external faces of the
blocks to the faces of the grooves Z, Z, any passage of steam from the upper
to the under side of the piston, or vice versa, may be prevented; I, I, are two
external slides, which are also passed over the arms C, C, and fit close to the
flanges Q, Q, of the grooves Z, Z, and work up and down with the arms C, C,
being of such greater length than the grooves Z, Z, as to close them completely
throughout each stroke of the piston. The faces of the flanges Q, Q, and of

page_text: the slides I, I, should be planed and ground so true as to fit very closely the
one to the other; L, L, are two strips of iron with bevilled faces, which,
for the sake of additional security against leakage, are screwed on the faces of
the flanges Q, Q, and bear against the sides of the two slides; E, (Figures 1ª
and 2) is a connecting rod with a cross head F, and two legs D, D,
which are attached to the piston arms C, C, by means of which forked con-
necting rod the motion of the piston is conveyed to the cranks G, G. Should
the sliding blocks M, M, and external slides I, I, work less true from use, or
should it be deemed advisable to provide against their being impaired by use,
they may be packed with hemp, by forming grooves on their faces, and filling
these grooves with ordinary hemp packing.
The second of my said improvements consists in certain new arrangements
of machinery by which the number of strokes of a marine steam engine and
the number of revolutions of the paddle-wheel shall be so adjusted in relation
the one to the other that each shall produce its greatest useful effect, and by
which also the relative rates of the stroke of the engine and paddle-wheel, or
other propeller, may be varied so as to suit the velocity of the vessel, whether
lightly or heavily laden, the speed of the engine thereby being maintained as
near as may be at a proper rate, or the engine and paddle-wheel may with
great facility be thrown altogether out of work whenever that may be found
expedient.
A transverse view of these new arrangements in their general combi-
nation is given in Figure 1b; A, A, A, is the line of main shafts of the engine,
which, instead of passing through the ships sides to the spring beams O, O,
terminate on each side at the bearings C, C, in the sides of the ship; D, D,
are the paddle shafts, placed parallel to the main line of shaft A, A, A, and at
some distance from it, (either before or abaft, above or below it, according as
circumstances may render advisable,) and extending from the bearings E, E,
on the spring beams 0, 0, to bearings F, F; on the main frames B, B, of the
engine on the line of main shafts, are affixed on each side three moveable
driving pinions 4, 5, and 6, which are of different diameters, and when in gear
work into three spur wheels 1, 2, 3, which are made fast to the paddle shaft;
x, y, z, are clutch handles by which the moveable pinions 4, 5, and 6 may be
thrown in or out of gear at pleasure. In this way I am enabled to drive the
paddle-wheels (P, P,) at three different rates of speed, according as one or other
of the pinions is in gear. When the immersion of a vessel and the state of the
weather are such that every stroke of the engines can produce a corresponding
revolution of the paddle-wheels, then the pinion 6 and wheels 3, which are
of equal diameters, are put into gear, and the engine and wheels work at

page_text: precisely the same speed, say, for example, twenty strokes each; but supposing
that, either from increased draught of water or from opposing winds, the
wheels cannot be kept up to the same speed as the engines, then the pinion
5 and wheel 2, which are in the proportions of seventeen to twenty, are
brought into gear and the others thrown out of gear, the effect of which is, that
while the engines continue to make their twenty strokes as before, the number
of revolutions of the wheel is reduced from twenty to seventeen. Should
the speed of the wheels become still further reduced by greater draught of
water or more adverse gales, recourse is then had to the pinion 4 and wheel 1,
which are in the proportion to one another of fourteen to twenty, by which means
the number of revolutions of the wheels are reduced in the same proportion.
By thus adjusting or proportioning the work to the power and protecting
the engines from the reacting influence of the encreasing resistance to the
rotation of the wheels, the maximum of useful effect of which they are
capable is obtained from them; that is to say, the engines continue to perform
always the same number of strokes nearly per minute, though the number
of revolutions of the wheels per minute may be diminished from twenty to
seventeen, and again from seventeen to fourteen, whereas but for the employ-
ment of gearing in the manner before described, not only would the encreasing
resistance to the rotation of the wheel have brought down the speed of the
engine, and that at times when it is of the utmost importance they should
possess their greatest effective power, but the revolutions of the wheel itself
would be reduced in number much lower than even the lowest of the numbers
represented by the driving pinions. The time occupied in throwing one set of
pinions out of gear and another into gear, need not exceed two or three
minutes. When it is desired to suspend the use of steam power altogether,
all that is required to be done, is to throw the whole of the pinions out of
gear. In adapting the machinery before described to the three different rates
of speed of twenty, seventeen, and fourteen revolutions of the wheels per
minute, I have considered that these are the rates most required to be pro-
vided for in the ordinary practice of steam navigation; but any other rates
of speed, and also any greater number of rates than three, may be provided
for by adopting different proportional diameters for the wheels and pinions,
and multiplying the number of pairs or sets employed. An inner side view
of the triple gearing represented in Figure 1b is given in Figure 2b, but does
not require any separate description.
The third of my said improvements consists in so constructing the pistons
of steam cylinders, that the stroke or range of the piston may be varied in
the same cylinder, without any attendant loss of steam either at the top or

page_text: by means of which the stroke of the piston may be lengthened (within the
limits of the cylinder) or shortened at pleasure, and the paddle-wheels or other
propellers may be promptly disconnected from the engines. I make use of
two cranks, one of which is immediately connected with the engine shaft and
the other with the paddle shaft; the former I call the main or driving crank,
the latter the paddle shaft or driven crank. Figures 1d to Figure 6d inclusive
represent these cranks and their appendages in as many different aspects as
A
seem to me requisite to make their manner of action clearly understood.
is the driving crank, and Y the driven crank; B is the main boss of the
driving crank, by which it is firmly keyed to the main shaft C of the engine;
D is a strong slide, which is fitted very exactly to the shank E of the driving
crank A, and has a projecting pin F, the toe of which, G, passes into a recess
provided for it in the crank Y, and forms the connection by which the driving
crank carries the driven crank round with it. On the slide D of the main
crank A is fixed a strong nut H, through which a strong screw, I, passes,
which works at one end into the body of the crank at P, and at the other into
the crank shank E; J is a projecting part by which this screw can be turned
round at pleasure, and L is a pin which goes through the groove K and holds
the screw in its place. From the manner in which this screw is connected
with the other parts of these crank arrangements it follows, that according as
it is turned to the right or to the left, the slide D and the crank pin F, with
its projecting toe G, must approach to or recede from the centre of the main
shaft C, and thereby cause the piston (through the medium of the usual
connecting rod) to shorten or lengthen its stroke in the same degree, while at
the same time the approximation of the slide and crank pin towards the centre
of the main shaft or recession from it causes the projecting toe G of the crank
pin to slide either too or fro within the cheeks or collar of the driven crank
Y, and so to produce a corresponding change in the throw of the driven crank.
To disconnect entirely the one crank from the other, and by that means the
paddle-wheels from the engines, all that is necessary is to turn the regulating
screw I until the driven crank pin F and its toe G are withdrawn entirely
from between the cheeks a, a, of the driven crank Y into the open space at Z,
as shown by the dotted lines, see Figures 1d and 3d, which they move freely
round without touching the driven crank Y, while on the other hand the
driven crank Y may revolve as freely without touching the driven crank A.
The fifth part of my said Improvements consists of another method repre-
sented in Figures 1° to Figure 5° inclusive, by which two cranks may be
disconnected at pleasure; A (Figure 1°) is the main or driving crank; B the
main shaft on which A revolves; C the crank pin with its projecting toe; D,

page_text: bottom. The means by which this is accomplished are represented in the
sectional elevation, Figure 1: A is the cylinder, N the piston, C, K, the piston
rod, and B the stuffing box. The piston, which I call an expanding piston,
consists of two distinct parts Z, Z, of the same superficial area as the cylinder,
each part having a separate packing (0, 0,) and of an intermediate or centre
piece E, which is firmly keyed to the piston rod C, K; F is one of three
screws which pass through the centre piece E, turning freely therein, and
held by collars and working into nuts G, G, in the upper and lower parts Z, Z,
of the piston. The upper end of each screw has a right-handed thread cut
upon it, and the lower a left-handed thread, so that according as the screws
are turned to the right or to the left, the upper and lower parts of the piston
are caused to approach to or recede from one another. The piston is repre-
sented in Figure 1° as expanded to the full extent of the screws, but when
the two parts are brought close together, they will be in the position indicated
by the dotted lines. Now, supposing that a piston of the common construc-
tion were employed and worked in the ordinary way, and that it were required
to make the longest stroke the length of the cylinder will admit of, its position
in the cylinder would be coincident with that of my expanding piston when
its upper and lower parts are brought close together, as represented by the
dotted lines in the Figure. But when for any reason it is deemed advisable
to shorten the length of the stroke, say for example six inches, there is a
space of three inches left above and below the piston more than is wanted for
clearance, and these spaces being filled with steam at each stroke, there is
just so much steam wasted. By the substitution however of my expanding
piston for the common piston, this source of loss is completely avoided, exactly
in the proportion in which the stroke is required to be shortened or lengthened;
the space occupied by the piston can be increased or diminished by causing
the top and bottom parts to recede from or approximate to one another, by the
means and in the manner before described.
The recess H (Figure 1) in the cylinder cover is one of three recesses left
for the reception of the top points of the regulating screws when the top and
bottom parts of the piston are brought close together; and M, M, are two of
four recesses left in the bottom of the cylinder for the reception of the bottom
parts of the said screws and of the end K of the piston rod. (See also
Figure 5.) Figure 2° is a bird's eye view of the cylinder top; Figures 3° and
4°, plans of the piston and the right and left handed screws; Figure 5º, a plan
of the cylinder bottom. The parts marked H, H, H, in Figures 2º, 3º, and
4°, last referred to, indicate the positions occupied by the three regulating screws.
The fourth of my said Improvements consists in certain additions to cranks

page_text: which is easily done by first slackening the nut K, and turning the head a
quarter round, and then tightening the nut again, it follows that the recess
L, L, can no longer coincide with the plane of rotation of the crank pin D,
which becomes therefore fixed in the recess, and so connects the driven crank
B firmly to the driving crank A for all purposes of propelling, whether forward
or backward. Whenever it is desired to disconnect the two cranks, all that is
required to be done is to slacken the nut K again, and restore the circular
head to its previous position, when the recess L, L, coinciding once more with
the plane of the crank pin, both cranks will move freely and independently of
each other. The toe pin D is flattened a little at the sides m, m, as shown in
Figure 4', in order to give greater clearance for the groove in the circular head
and the toe pin.
And having now fully described the whole of my said invented Improve-
ments in the construction of steam engines, and in the application of steam
engines for propelling ships and other vessels, I declare that what I claim as
new and of my Invention under each of the heads into which the said Improve-
ments are divided as aforesaid, is as follows:-
First, I claim the piston, with arms projecting through the sides of the
cylinder and working up and down in grooves therein, with a connecting rod
from which motion is communicated directly to the beam or crank of an
engine, without the intervention of a piston rod, parallel motion mover, or any
analogous contrivances, and also the method by which the said grooves are
made air and steam tight.
Second, I claim the method of reducing or augmenting the speed of
a paddle-wheel, whilst the engine is kept up at its maximum effective speed,
or nearly so, by attaching to the engine and paddle shafts three or more
sets of toothed wheels and pinions of different proportional diameters, and
transmitting the power of the engine through one or other of these sets of
gearing; and also the method of entirely disconnecting the paddle-wheels
from the steam engine, by throwing the whole of the said pinions out of gear.
Third, I claim the expanding piston of the construction herein-before parti-
cularly described, by which the stroke or range of the piston may be varied
in the same cylinder without any loss of steam taking place.
Fourth, I claim the employment for propelling purposes, and for driving
machinery in general wherever applicable, of two cranks in the manner before
described; one called the main or driving crank, having a sliding crank pin, and
the other called the driven crank, having oblong collars with parallel sides for
the reception of the said sliding pin, whereby I am enabled to alter at pleasure
the throw of the main or driving crank, and to disconnect entirely the one
crank from the other whenever that is found advisable.

page_text: which is flattened at its sides in order that it may have a greater bearing on
the jaw I presently herein-after described, and so be less liable to tear and
wear; E is the driven crank, and F the driven shaft on which it revolves; H is
a strong slide which is affixed to the shank G of the driven crank, having an
open jaw I with two parallel sides K, K (Figures 3 and 4°), the depth of which
jaw, clear of the shank G, that is, from L, L (Figures 1° and 2°), is such as to
correspond exactly with the length of the projecting toe D of the driving crank
pin C; M is a strong nut attached to the slide H, through which nut is passed
a screw N, the inner end of which is housed in the body of the driven crank
E at O, and the outer end in the shank thereof at P; Q is a small orifice in
the screw by passing the pin R, through which it is kept in its place (Figures
2 and 3); a wrench or spanner being applied to the end S of the screw N
and the screw turned, the open jaw J is caused to recede towards the centre of
the crank E till it attains the position T (Figure 1° and 2), when the
projecting toe D of the driving crank pin C becomes liberated from it, and the
driving crank and pin can revolve freely without touching the driven crank,
which on the other hand can revolve equally freely without interfering with
the driving crank.
The sixth and last of my said Improvements consists in a third method of
connecting and disconnecting at pleasure a driven crank from a driving crank,
as the same is represented in Figure 1'to Figure 4' inclusive. A is the driving
crank, B the driven crank, C the main crank pin, with its projecting toe D,
E the main or engine shaft, and F the driven shaft; G is a moveable circular
head, which is inserted in the boss H at the end of the driven crank, and
moves freely round in it within the limits herein-after specified. On the
inner end I of this moveable head a strong screw J, J, is cut, which takes into
a nut K at the back, by which means the head is firmly secured to the driven
crank B. In the boss H there are quarter circle grooves c, d, (Figure 3' and
4) formed, in which the stops a, b, attached to the circular head, move so as
to limit the movement to and fro of that head to a quarter of a circle; L, L, is
a recess of the form of the segment of the circle (Figure 3' and Figure 4), cut
out of the face of the circular head G for the reception of the projecting
toe D of the main crank pin, and corresponding with it in depth and diameter;
according to the position given to this recess by the moving partly round of
the circular head G, it may either coincide with or cross the plane of rotation
of the main crank pin. In Figure 3 it is shewn as coinciding with the plane
of rotation of the main crank pin, which allows the main crank to move
round freely without interfering with the driven crank. But suppose the
circular head G is turned round one quarter of a circle, as shewn in Figure 4',

page_text: Fifth, I claim the method of connecting and disconnecting two cranks by
attaching a strong slide and jaw to the driven crank, with a screw to move it
backwards or forwards, so that according as the screw is turned to the one
side or the other, the pin of the driving crank is either held firm within the
jaw of the slide or liberated from it, and the two cranks left free to revolve
independently the one of the other.
And sixth, I claim the method of connecting and disconnecting two cranks
by means of a circular moveable head, or a moveable head of any other suitable
form attached to the boss or end of the driven crank, and provided with a
recess in the face thereof for the reception of the toe of the crank pin of the
main or driving crank, by the turning of which circular head to one side or
the other the said recess is caused to coincide with, or cross the plane of rota-
tion of the main crank pin, whereby the said crank pin is either held firm in
the recess, or left free to move round without interfering with the driven crank.
And such my said invented Improvements being, to the best of my knowledge
and belief, entirely new and never before used within that part of Her said
Majesty's United Kingdom of Great Britain and Ireland called England, Her
said Dominion of Wales, or Town of Berwick-upon-Tweed, and Her said Colo-
nies and Plantations abroad, I do hereby declare this to be my Specification of
the same, and that I do verily believe this my said Specification doth comply in
all respects fully, and without reserve or disguise, with the proviso in the said
herein-before in part recited Letters Patent contained: Wherefore I do hereby
claim to maintain exclusive right and privilege to my said Invention.
In witness whereof, I, the said Samuel Seaward, have hereunto set
my hand and seal, this Seventeenth day of September, in the year of
our Lord One thousand eight hundred and forty.
SAMUEL (L.S.) SEAWARD.