AN IMPROVED ENGINE PARTICULARLY APPLICABLE TO LOCOMOTIVE PURPOSES AND STEAM NAVIGATION
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ERICSSON, of Cambridge Terrace, Edgeware Road, in the County of Middlesex,
Civil 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 Sixth day of July, in the third year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said John
Ericsson, Her especial licence, that I, the said John Ericsson, my exors, admors,
and assigns, or such others as I, the said John Ericsson, my exors, admors,
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 law-
fully might make, use, exercise, and vend, within England, Wales, and the
Town of Berwick upon Tweed, my Invention of "AN IMPROVED ENGINE
PARTICULARLY APPLICABLE TO LOCOMOTIVE PURPOSES AND STEAM NAVIGATION;" in
which said Letters Patent is contained a proviso, obliging me, the said John
Ericsson, by an instrument in writing under my hand and seal, particularly to
describe and ascertain the nature of my said Invention, and in what manner
the same is to be performed, and to cause the same to be enrolled in Her said
Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said recited Letters Patent, as in and by
the same, reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Ericsson, do hereby declare the nature of my said Invention as applied
particularly to locomotive purposes, (that is, for giving motion to the driving
wheels of the locomotive carriage,) to consist of two radial pistons, perform-
ing partial rotary and reciprocating movements within two half cylindrical
chambers, placed horizontally and transversely on the carriage, and being
attached to each other, the axes or shafts to which the said pistons are fixed
(and which form their centre of motion) being made to pass through stuffing
boxes in the covers of the said half cylinders, and extending in opposite
directions beyond the outside frame of the carriage, the ends of these shafts
being provided with crank levers, which by means of connecting rods and pins
are connected to circular discs or cranks fixed on the outer ends of the axis of
the driving wheels. And as applied particularly to steam navigation, (that is,
for giving motion to the ordinary paddle wheels or to any rotary stern pro-
pellers,) my improved engine consists of similar radial pistons, axes, levers,
and connecting rods, performing similar reciprocating and partial rotary move-
ments, and working within half cylinders, placed either transversely or longitu-
dinally in the vessel and attached to each other. And in further compliance
with the said proviso, I, the said John Ericsson, do hereby describe the manner
in which my said Invention is to be performed by the following statement
thereof, reference being had to the Drawings annexed, and to the figures and
letters marked thereon, that is to say :-
DESCRIPTION OF THE DRAWINGS.
Figure 1 represents a side elevation, and Figure 2 a plan, of a locomotive
carriage with my improved engine applied, drawn to a scale of half an inch
to a foot. Figure 3, which is drawn to a scale of two inches to a foot, repre-
sents a transverse section of the two half cylinders and pistons. I will first
proceed to describe this Figure. A and B are two half cylinders, secured by
screws to a bridge or abutment piece C, made of cast iron; D, d, are axes or
shafts passing through stuffing boxes in the covers of the cylinders, and to which
shafts radial pistons E, E, are attached; the said stuffing boxes as well as the
packings of the pistons will be hereafter described. F, F, are square metallic
rods inserted into grooves made in the abutment piece; these rods are made
to press against the piston shaft by means of springs, in order to prevent any
steam from escaping round the same. G is an ordinary slide valve for
admitting the steam through the passages a, a, alternately on opposite sides
of the piston of the cylinder A. Behind the valve G is a similar valve, placed
within the common slide box H, which slide through passages similar to A.

page_text: A admits the steam alternately on opposite sides of piston of the cylinder B.
I is a cavity made in the abutment piece, into which and through the eduction
pipe J the steam escapes into the chimney and ultimately into the atmosphere.
K is the induction pipe admitting steam into the slide box H; L is a spindle
and lever for giving motion to the slide valve. I will now proceed to describe
Figures 1 and 2, in which similar letters of reference denote similar parts as
in Figure 3. A and B are the half cylinders, and M, M, the stuffing boxes
in the cylinder covers, through which the piston shafts or axes D and d pass;
N and O are crank levers, placed at right angles to the pistons, and firmly
fixed at the opposite ends of the piston shafts D and d; n, o, are crank pins
fixed in the said levers; P and Q are circular plates or dises firmly fixed to
the ends of the axle of the driving wheels R, R; p an 9 are what are
commonly called crank pins (of a globular form) fixed at right angles to each
other in the circular plates. The crank pins n and p, and the crank pins
o and q, are connected by means of ordinary connecting rods, the centre lines
of which are marked in red lines. S, S, are bearing brasses fixed in the outside
framing of the carriage for supporting the piston shafts D and d; s, s, are
keys for adjusting the same; T, T, are eccentric circular bosses on the inside
of the circular plates, to which ordinary straps and slide gear is attached for
giving motion to the two slide valve spindles; (one of these spindles L is
shewn on the elevation.) V is a lever attached to the piston shaft D for
working a force pump for supplying the boiler. I have now to state that tho
position of the eccentric bosses T, T, with regard to the crank pins p, q, should
be similar to the eccentrics of ordinary steam engines, and likewise the gear
work for communicating the motion of the eccentric bosses to the slide valves
G. With regard to the operation or motion of the engine, it becomes evident
that when steam is admitted into the slide box H, and the alternate move-
ment given to the slide valves, a reciprocating and partly rotary motion will
be given to the pistons and their shafts, and thereby a vibrating motion to the
crank levers N and O. These crank levers being connected to the pins p and q,
which are placed at right angles to each other, it follows that a continuous
rotary motion will be given to the driving wheels of the carriage.
Having thus described my improved engine as applied particularly to
locomotive purposes, I will now procced to describe the same as applied
particularly to steam navigation.
Figure 4, which is drawn to a scale of half an inch to a foot, represents the
transverse section of a steam vessel with a front view of my improved engine;
and Figure 5, which is drawn to a scale of three-sixteenth parts of an inch to
the foot, represents the longitudinal section of a steam vessel with a side eleva-

page_text: tion of my improved engine. In order more clearly to exhibit the various
parts, it will be seen that in Figure 4 the exterior view of one half of the
engine is shewn whilst the other half is shewn in section. A and B are two
half cylinders, provided with flanges, which are attached to cast-iron frames
C, C; these frames being divided at c, c, each half serving the purpose of end
cover to the cylinders, and firmly bolted together at c, c. These frames or end
covers C, C, are firmly bolted to timbers placed longitudinally at the bottom
of the vessel. D and E are the piston shafts, to which the radial vibrating
pistons,. as before described, are attached, e being the piston attached to the
shaft E. a, a, are plummer blocks or bearings in the frames C, C, for carrying
the piston shafts, and k, k, are keys for adjusting these bearings; F, F, are
the top covers of the cylinders, and f is one of the metallic rods for
preventing any escape of steam round the shaft; G is a double acting air
pump, constructed upon the same principle as the steam cylinders, with
a similar vibrating radial piston, as shewn by dotted lines on the Draw-
ing; H is a condensor with a rose jet h, similar to those used in common
condensing engines; I is the suction valve, and the valve communi-
cating to the hot well J; g is a crank lever attached to the piston shaft of
the air pump, and d is another crank lever attached to the end of the piston
shaft D. These crank levers give motion to the piston of the air pump by
means of a connecting rod K. 1, 1, are the steam passages; and L, the
eduction valve, by which the steam is alternately let into the conderser. This
valve, as well as the induction valve, is worked by ordinary gear communi-
cating with the main shaft. The steam passages communicating between the
induction valve and the cylinder are placed behind the passages 1, 1, and simi-
larly constructed, as will be seen in Figure 5. The induction valve itself may
be constructed either upon the principle of the ordinary slide valve, or like the
eduction valve L. M and N (shewn by dotted lines in Figure 4) are crank
levers fixed to the ends of the piston shafts; the extent of the motion of these
crank levers is marked by red lines in Figure 4. O is the main shaft of the
engine, and the continuation thereof is a paddle shaft, which passes through
the stern of the vessel, for the purpose of giving motion to either a wheel
constructed with spiral plates, or to a screw, or to any other rotary propeller.
R, R, are brass bearings fitted into the lower part of the frames C, C, for
carrying the main shaft O. 1, r, are the caps for securing the said brass
bearings. S is a circular plate of iron firmly attached to the main shaft. s is
a double crank pin fixed in this circular plate, and which pin, by means of
connecting rods U and V, is connected to the pins m and n of the crank levers
M and N. I have here to observe that the relative position of the cylinders

page_text: and the centre of the main shaft should be such, that straight lines drawn
through the extreme points of motion of the centres X and Y of the crank
pins m and n should intersect each other at right angles in the centre of the
main shaft, as shewn by the red lines in Figure 4. 'Figure 6 represents the
side view of one of the radial pistons, and shows the mode in which they are
made to form steam-tight joints with the cylinders, as well as the mode of
preventing the steam from escaping at the places where the piston shafts pass
through the end covers. A is the piston shaft; and B, the piston. The dotted
lines marked round it shew the form of the metallic rods and angle pieces
inserted between the slide plates of the piston (better seen at Z in Figure 4).
These angle pieces are pressed towards the side of the cylinder by springs
similar to those used in ordinary metallic pistons. C is a ring of gun metal,
which, by means of common hemp packing and a packing ring or gland D, is
pressed against the shoulder of the shaft at c, c, thereby preventing any escape
of steam. With regard to the operation or motion of the engine, I have only
to state that, by the steam being admitted alternately on opposite sides of the
pistons, and alternately let into the conderser in the usual manner, a continuous
rotary motion will be given, to the circular plate S by means of the crank
levers, pins, and connecting rods, before described; for it is evident that when
one connecting rod is in a direct line with the centre of the crank pins and
the centre of the main shaft, the other connecting rod will be placed nearly
at right angles to the crank pin and the centre of the main shaft, thereby
promoting the desired continuous rotary motion.
Now, whereas it is evident that by changing the position of the crank levers
attached to the piston shafts the main shaft O may be placed above the centre
of the half steam cylinders as much as it is placed below the same in Figure 4,
and it is evident that by placing the cylinders transversley in the vessel instead
of longitudinally, motion may be given to a common paddle shaft in the
manner before described, whether the cylinders are placed above the shaft, as
in Figure 4, or below the same to an equal degree, as shewn in Figure 7, in
which latter Figure similar letters of reference denote similar parts as in
Figure 4: and whereas I claim as my Invention the improved engine herein-
before separately described in its application to locomotive purposes and to
steam navigation, and such my Invention 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, 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