AN IMPROVED STEAM ENGINE
Year: 1838

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ERICSSON, of Berkeley Street, Connaught Square, 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
Westminster, the Sixteenth day of February, One thousand eight hundred
and thirty-eight, in the first year of Her reign, did, for Herself, Her beirs
and successors, give and grant unto me, the said John Ericsson, Her especial
license, full power, sole privilege and authority, that I, the said John Ericsson,
my exors, adñiors, and assigns, or such others as I, the said John Ericsson,
my exors, adñiors, 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, my Invention of "AN IMPROVED
STEAM ENGINE;" in which said Letters Patent is contained a proviso that I,
the said John Ericsson, shall cause a particular description of the nature of my
said Invention, and the manner in which the same is to be performed, 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 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 compliance with the said proviso, I, the said
John Ericsson, do hereby declare the nature of my said Invention to consist

page_text: in obtaining from the reciprocating motion of a reciprocating steam engine
piston a continuous rotary motion by means of two revolving toothed wheels
turning in opposite directions, to which a friction piece or clutch, connected
with the axis of the piston, is geared alternately, the said two toothed wheels
giving motion in one uniform direction to a third toothed wheel connecting
or communicating with the driving shaft; 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, reference being had to the
Drawing annexed, and to the figures and letters marked thereon, similar
letters of reference being used to denote similar parts in all the Figures, that
is to say:
Figure 1 represents partly a longitudinal elevation and partly a longi-
tudinal section of my improved steam engine. Figure 2, a transverse
section, Figure 3, an end view, and Figure 4 a plan. A is the working
or steam cylinder; B, B, B, is the driving shaft to which the piston M
is attached, which shaft is made hollow from 6 to b; C is a circular boss
of cast iron, which I call a friction plate, attached to the driving shaft
by means of steel keys c, c, which keys are fixed to the friction plate, and
pass through elongated holes made in the driving shaft, admitting of a longi-
tudinal sliding of the friction plate upon the shaft; D is a steel rod working
within the driving shaft, and fixed to friction plate by the keys c, c.
It is pro-
vided with a square hole, through which a lever E passes, the fulcrum of which
lever consists of a steel pin e fixed on the driving shaft. This lever is moved by
a double lever F, a side view of which is separately given in Figure 5; a square
collar works on the central bearing of the double lever F, and is made to slide
up and down in the top part of the lever E during the motion thereof; G is a
loose ring on the driving shaft, which is connected to the double lever F by
means of its ears 9,9, and links h, h; H, I, are two conical wheels working
freely on the driving shaft. These wheels are provided with large bosses i, i, i, i,
which are made to press against the friction plate at its circumference; p, p, is
a collar fixed on the driving shaft; and J is a loose collar by which (by means
of a key ;) the bosses of the conical wheels may be brought in contact with
the friction plate; K is a small steam cylinder attached to the side of the
working cylinder A; L is the piston of the small cylinder K, and the piston
rod thereof, which works through the stuffing box k; M is the piston of the
working cylinder, and m its metallic packing; N, the abutment piece, and
n the metallic packing for making a steam-tight joint with the driving shaft;
O is the eduction pipe or channel for carrying away the steam; P is the
induction pipe; Q, the slide box, and R the slide valve, which is worked

page_text: by the tooth fixed in the spindle r; S and T are the steam passages of
the working cylinder A; s is a small channel or steam passage communicating
with the steam passage S; and t a channel between the small steam cylinder K,
before described, and the steam passage T; U is a cock provided with two
holes and two cross passages, as shewn separately in Figure 6. W; Figure 3,
is a quadrant fixed to the end of the driving shaft. To this quadrant two
tappets w, v, are attached, which tappets are intended to work the slide
valve R by striking the spring levers X, x, which are fixed to the spindle r;
Z, (Figure 4), is a lever by which the motion of the piston rod is commu-
nicated to the ring G, and ultimately to the friction plate. This lever is made
in the form of a fork at both ends; the smaller fork z being placed between
the collars of the small piston rod 1, and the larger fork working in the groove
of the ring G; V is a conical wheel attached to the machinery to be worked,
and which conical wheel works into the conical wheels H, I.
Having thus described the construction of my improved engine I will now
proceed to describe the manner in which the same is to be put into operation.
Steam being admitted into the slide box the piston M moves to the left, in
the direction of the arrow (Figure 2), and when it approaches the abutment
piece N (Figure 2) the tappet w strikes the spring lever a, by which the
position of the slide valve is changed and the steam made to enter the
cylinder from the opposite side so as to force the piston back. On arriving
again at the opposite side of the abutment piece, the tappet v strikes the
spring lever X, by which the slide valve is brought back to the position shewn
in Figure 2. A reciprocating motion is thus at one and the same time given
to the piston, and to the driving shaft, and to the friction plate. I have before
stated that there is a small channel t communicating between the steam
passage T of the working cylinder A, and the small cylinder K. Now, the
pressure of the steam against the small piston L, of the small cylinder K,
pulls the rod to the left, and by means of the levers, links, and rods before
described, the friction plate C is also pulled in the same direction, as indicated
by the arrow, Figure 1, and thereby brought in contact with the cog
wheel H, which thus becomes locked, when of necessity the driving wheel V
commences revolving to the left and the cog wheel to the right. The
small channel & communicating with the steam passage S, it follows that when
the piston M has completed its motion to the left, the slide valve is pushed to
the right, by which means the cog wheel I becomes in its turn locked, and is
made by the power of the piston to revolve to the right, which is in the same
direction in which it was previously moved by the driving wheel V. Hence a

page_text: continued rotary motion is given to all the wheels in the directions indicated
by the arrows. I have now to state, that by giving one quarter of a turn to
the grooved cock U, I am enabled to reverse the motion of the driving
wheel V, for by so far changing the position of the cock the small steam
channel t is made to communicate with the steam passage S instead of T, and
the small channels is made to communicate with the steam passage T instead
of S, so that the cog wheel I becomes locked to the friction plate, when the
piston M moves to the left, and the cog wheel H is locked when the piston
moves to the right, from all which it follows that the driving wheel V must
move to the right instead of moving to the left. Now, whereas, it is evident
that the extra piston and rod which move the lever acting upon the friction
piece or clutch may be placed inside the main cylinder, as shewn at Figure 7,
as well as outside, as shewn in the other Figures.
And having now particularly described the nature of my said Invention, and
in what manner the same is to be performed, I hereby declare that I do not
claim a cylinder with a reciprocating piston alone, as any part of my said
Invention. But I hereby claim as my Invention the improved steam engine,
herein-before described, whereby I obtain from the reciprocating motion of
the steam engine piston a continuous rotary motion through the medium of two
cogged wheels turning in opposite directions, and acting upon a third cogged
wheel on the driving shaft, or connected or communicating with it, such two
cogged wheels being acted upon alternately by the friction piece or clutch
(for the said clutch may act with teeth or bosses instead of by friction), as
herein-before described. 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 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 John Ericsson, have hereunto set my
hand and seal, this Sixteenth day of August, One thousand eight
hundred and thirty-eight.
JOHN (L.B.) ERICSSON.

page_text: AND BE IT REMEMBERED, that on the Sixteenth day of August,
in the year of our Lord 1838, the aforesaid John Ericsson came before
our said Lady the Queen in Her Chancery, and acknowledged the Specifi-
cation aforesaid, and all and every thing therein contained and specified,
in form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Inrolled the Sixteenth day of August, in the year of our Lord One thou-
sand eight hundred and thirty-eight.