CER- TAIN IMPROVEMENTS IN ENGINES FOR OBTAINING AND APPLYING MOTIVE POWER
Year: 1847

page_text: SCOTTHORN'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
SCOTTHORN, of Somers Town, in the County of Middlesex, Engineer, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her.
Royal Letters Patent under the Great Seal of the United Kingdom of
Great Britain and Ireland, bearing date at Westminster, the Seventeenth
day of March, One thousand eight hundred and forty-seven, in the tenth
year of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Robert Scotthorn, my exors, adñiors, and assigns, Her
especial licence, full power, sole privilege and authority, that I, the said
Robert Scotthorn, my exors, admiors, and assigns, or such others as I, the
soid Robert Scotthorn, my exors, adiñors, or assigns, should at any time agree
with, and no others, from time to time and at all times thereafter 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
in all Her Majesty's Colonies and Plantations abroad, and also in the
Islands of Jersey, Guernsey, Alderney, Sark, and Man, my Invention of "CER-
TAIN IMPROVEMENTS IN ENGINES FOR OBTAINING AND APPLYING MOTIVE POWER;"
in which said Letters Patent is contained a proviso that I, the said Robert
Scotthorn, shall cause a particular description of the nature of my said
Invention, and in what manner the same is to be performed, by an instrument
in writing under my hand and seal, to be inrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately

page_text: 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
Robert Scotthorn, hereby declare that the nature of the said Invention, and
in what manner the same is to be performed, are fully described in and by the
present Specification thereof, reference being had to the Drawings hereunto
annexed, that is to say :-
My said improvements have relation to that class of engines in which the
expansive force of steam is applied directly to produce a rotary motion of the
main shaft of the engine without the intervention of piston rods, connecting
rods, and other contrivances, and are embodied in an engine of the construction
represented in the annexed Drawings.
Figures 1 and 2 of these Drawings are elevations of the opposite ends of
the engine; Figure 8, a sectional plan on the line a, b, of Figures 1 and 2;
and Figure 4 an end elevation of Figures 1 and 2, with the cover removed to
shew the internal arrangements. A, A, is a hollow metallic case, which
contains a central cylindrical chamber C, and two smaller side chambers
B, B, each of which is two thirds of a circle. The axial lines of all the
three chambers are in the same plane, parallel and equidistant, but the circle
represented by the central chamber is struck from a larger radius than the two
side chambers, which causes it to intersect and cut off portions of each of the
latter. The two side chambers B, B, have two steam abutment pieces
B¹, B, of exactly the same shape fitted into them, which form on the sides
where they are cut away (so to speak) portions of the solid sides of the central
chamber C. D is a hollow cylinder, which is fixed upon the main shaft E,
and is of exactly the same length as the two abutment pieces B¹, B. F is a
piston which projects from one side of this cylinder, and is fitted with a
metallic packing f, which forms a steam-tight joint with the inner surface of
the central chamber C, and those portions of the abutment pieces B', B',
which form part of the circumference of the cylinder C. X', X³, are axles or
spindles which are securely inserted into the abutment pieces B³, and B', so that
when these spindles are turned the abutment pieces must turn along with
them. G, G, are two covers which fit the ends of the case, and are provided
with stuffing boxes c, c, c, c, to prevent the escape of steam at the apertures
by which the main shaft and the spindles X', X³, are passed through the
covers G, G. The main shaft E (see sectional plan, Figure 3,) is made
hollow from each end to near the centre of the case, where the hollow spaces
d', e', turn off at an angle through the metal cylinder D, and form openings d³, e³,
into the cylinders C, one opening being on the one side of the projecting

page_text: piston F, and the other being on the reverse side, as indicated by the dotted
lines in Figure 4. The passage d' and opening e' serve for the induction
port, and the passage d and opening e² for the eduction port. H³, H³, aro
two cams affixed to the main shaft E, which press against four friction
pulleys J, J, J, J, which are mounted upon four levers K, K, K, K, which
are again affixed to the spindles X', X. The office of the cam wheel H¹ is
to bring the abutment pieces B³, B², into the position which B' is represented
as occupying in Figure 4. in which position it divides the space left between
the outer case A and the internal cylinder D into two compartments L³, L³.
These compartments are rendered steam-tight by the metallic packings f
and m, along the sides of the cylinder D, and at the ends by the covers G, G.
The office of the other cam H* is to bring the abutment pieces B', B³, into
the position occupied by B' in Figure 4. The mode of operation of the
engine is as follows:-Supposing steam to be admitted into the compartment
L', through the opening e', it presses against the piston F with a force equal
to that due to the pressure of steam in the boiler, but as the passage e³ is open
for the escape of air or steam from the compartment L², the cylinder D and
main shaft will consequently be turned round in the direction of the arrows.
When the projecting piston F has just cleared B³, and come to bear upon
the sides of the case or cylinder C, then the cam wheel H₁ causes the piece
B to assume the position in which B' is represented, and B at this instant
becomes the medium of resistance against which the steam is exerted, and
forms the division between the steam and exhaust sides of the cylinder C.
As the piston F approaches nearer to B', the cam wheel H* causes it to assume
the position in which B³ is represented in the Drawing, and so the action goes
on, the two cam wheels H' and H bringing the side pieces B¹ and B³ in
continuous succession into the different positions in which they are represented
in Figure 4, and thereby presenting a continuous succession of points of
resistance to the steam, and causing a rotation of the cylinder D and main
shaft E, from which the power may be applied to drive any kind of
machinery.
In the preceding description this engine has been exemplified as worked by
means of high-pressure steam. It may, however, be worked expansively,
by having an expansion valve attached to the steam pipe, or it may be
employed as a condensing engine, in which case the condenser would be
attached by means of a pipe to the aperture d³ in the main shaft E.
Again, instead of the cylindrical case (C) being made stationary, and the
shaft E to revolve, as before described, the shaft may be made stationary and
the cylindrical case to revolve, the power being applied to the working of

page_text: machinery through the medium of a toothed wheel bolted to the case. Or
both the case and the shaft might be made to revolve, but in opposite
directions, in which case the power obtained from them might be made
available by means of gearing common to both. An arrangement of gearing
suitable for this purpose is shewn in Figure 5.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that what I claim as the
improvements embodied in the direct action rotary engine and modifications
thereof, before described, and arising from the peculiar manner in which the
various parts of the said engine (as to which parts individually and separately
considered I make no claim) are arranged and combined as aforesaid.
In witness whereof, I, the said Robert Scotthorn, have hereunto-set
my hand and seal, this Seventeenth day of September, in the year
of our Lord One thousand eight hundred and forty-seven.
ROBERT (L.S.) SCOTTHORN.
AND BE IT REMEMBERED, that on the Seventeenth day of Sep-
tember, in the year of our Lord 1847, the aforesaid Robert Scotthorn came
before our said Lady the Queen in Her Chancery, and acknowledged the
Specification 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.
Enrolled the Seventeenth day of September, in the year of our Lord
One thousand eight hundred and forty-seven.
ROBERT (L.S.) SCOTTHORN.
AND BE IT REMEMBERED, that on the Seventeenth day of Sep-
tember, in the year of our Lord 1847, the aforesaid Robert Scottborn came
before our said Lady the Queen in Her Chancery, and acknowledged the
Specification 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.
Enrolled the Seventeenth day of September, in the year of our Lord
One thousand eight hundred and forty-seven.