IMPROVEMENTS IN THE MODES OF OBTAINING MOTIVE POWER BY A ROTARY OR CIRCULAR MOVE- MENT, AND OF APPLYING IT
Year: 1855

page_text: LETTERS PATENT to James Nasmyth, Civil Engineer, residing at St.
Germain in Laye, in France, for the Invention of "IMPROVEMENTS IN
THE MODES OF OBTAINING MOTIVE POWER BY A ROTARY OR CIRCULAR MOVE-
MENT, AND OF APPLYING IT."
Sealed the 20th March 1856, and dated the 26th September 1855.
PROVISIONAL SPECIFICATION left by the said James Nasmyth, at the
Office of the Commissioners of Patents, with his Petition, on the 26th
September 1855.
I, JAMES NASMYTH, Civil Engineer, residing at St. Germain in Laye, in
France, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MODES OF OBTAINING MOTIVE POWER BY A ROTARY OR CIRCULAR MOVEMENT,
AND OF APPLYING IT," to be as follows:-
I place a piston in a circular tube, in which there is a slit or an opening.
On the piston is fixed a metallic plate, which passes through the opening and
is joined to another metallic plate, which is fixed in the centre of a wheel of
suitable dimension, moving horizontally on a pivot.
The tube being in vacuo, the piston is propelled by the admission of air or
steam on one of its surfaces, by which motive power is obtained by a rotary or
circular motion.
In order to obtain the same object by another method, I make use of a.

page_text: Nasmyth's Im
locomotive engine instead of a circular tube placed at one
which the other end is fixed in a wheel moving on a pivot,
of a rod, of
through which it is
mmunication with a steam boiler, or a condensing or exhausted cistern,
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed 5
by the said James Nasmyth in the Great Seal Patent Office on the
26th March 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
NASMYTH, Civil Engineer, residing at Saint Germain in Laye, in France,
send greeting.
year of our
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of September, in the
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 James Nasmyth, Her special license that I, the said James Nasmyth,
my executors, administrators, and assigns, or such others as I, the said James
Nasmyth, 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 "IMPROVEMENTS IN THE
MODES OF OBTAINING MOTIVE POWER BY A ROTARY OR CIRCULAR MOVEMENT, AND OF
APPLYING IT," upon the condition (amongst others) that I, the said James
Nasmyth, by an instrument in writing under my hand and seal, should parti-
cularly 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.wo
NOW KNOW YE, that I, the said James Nasmyth, do hereby declare the
nature of my said Invention, and in what manner the same is to be per
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed, and t
the letters and figures marked thereon (that is to say): is
My Invention of improvements in obtaining motive power by rotary
circular movements, and in the application of the same to useful purpose
consists in placing a piston within a circular or annular tube, in which there
1

page_text: an annular slit or opening, through which opening an arm fixed to the piston
projects, and is made to act against another arm projecting from a vertical
or main shaft, from which shaft motion may be transmitted to machinery
by means of bands, pullies, or toothed gearing in the usual way. The arm
5 projecting from the piston before mentioned passes through a circular steam-
tight valve that covers the annular slit or opening, and which valve is caused
to travel with the piston as the latter performs its circular course in the
annular tube.
In order that my Invention may be clearly understood, I have annexed
hereto several Sheets of Drawings; in which Fig. 1 is a plan view of a rotary
steam engine constructed according to my improvements, part of the circular
valve being removed for the purpose of shewing the slit or annular opening
beneath; Fig. 2 is a transverse vertical section of the same; Fig. 3 is a section
taken horizontally; and Figures 4 and 5 are detached views of the piston.
a is the circular or annular steam tube or hollow ring in which the piston
works; b is the piston which circulates in the tube a; c is the annular slit or
opening, which is covered and closed by the circulating circular valve d, which
valve is attached to the piston and is moved by it. The construction of this
valve will be best understood upon referring to the sectional view, Fig. 2, and
the detached view, Fig. 4. This circular or annular valve is made in two
parts, and consists of a flat plate, which covers the slit or opening in the tube a,
and is provided at its edges with two T-shaped flanges, which run in grooves
bolted to the annular steam tube, as shewn in the cross section, and by their
peculiar form will make the valve steam-tight; and the more pressure is
exerted against the under side of the flat plate of the valve, the tighter the
T flanges will be pressed against the grooves, and prevent the escape of
steam through the annular slit or opening. e is a flat metallic plate or arm,
fixed vertically in the piston, and passing through the annular slit c and the
circulating circular valve d. l is a lever arm, one end of which is fixed on
a working shaft m, and the other end of this lever is placed before the flat
metallic plate or arm e projecting from the piston b. h and i are division
valves, which divide the tube a into two parts.
These division valves are opened by the piston b as it travels round, and
after it has passed these valves are shut and kept shut by springs k pressing
against their backs. When convenient, instead of these spring division valves
horizontal slide valves may be employed and worked by movements from the
shaft in the usual way. f and f¹ are the inlet valves to admit steam agains
the piston b. g and g' are two outlet valves for the steam to blow off, o
which may be made to open into pipes leading into condensing cisterns.

page_text: The operation of the several parts is as
to be
in the position shewn in Fig. 3, I open the inlet valve f to admit the steam
against it. The pressure of the steam drives the piston forward through the
division valve i. I then open the inlet valve f¹, and shut the inlet valve f and
open the outlet valve g; the steam passing through the inlet valve f¹ drives 5.
the piston 6 forward and through the division valve h, the part a¹ of the steam
tube from the outlet valve g to the division valve i having been cleared of
I then shut the inlet valve f¹ and the
steam by opening the outlet valve g.
outlet valve g, and open the inlet valve f and the outlet valve gl. The steam
passing through the inlet valve f drives the piston forward through the division 1
valve i, the part a² of the steam tube from the inlet valve f¹ to the division
valve h, having been cleared of steam by opening the outlet valve g¹. As the
piston 6 thus travels round, the arm e (projecting from it) will press against the
lever arm 1 of the vertical shaft m, which is thus caused to rotate, and by
means of bands or toothed gearing, to impart motion to other machinery, as
may be desired. The steam may either blow off through the outlet valves g
and g', or be conducted through pipes into condensing cisterns.
I have not considered it necessary to show any.particular contrivance for
working the inlet and outlet valves, as the mode of working these parts does
not form any part of my Invention, and those operations may be effected in
many ways that will readily suggest themselves to any intelligent mechanic; I
will, therefore, leave the arrangement of these parts to the discretion of the
mechanic or engineer, who may apply such mechanical contrivances as he may
deem most suitable for the purpose.
In Figures 6 and 7 I have shewn another method of obtaining motive
power by means of a rotary or circular movement, the impelling agent being in
this case the ordinary pressure of the atmosphere acting on one side of the
piston, while the other side of the said piston is in a state of vacuum.
It will be seen that the arrangement of the several parts of this rotary
atmospheric engine is in many respects the same as in the steam engine above
described; the same letters will therefore serve to indicate like parts in the twe
arrangements, so far as they correspond. The circulating circular valve d (i
should be understood) is in this case so made as to resist the external pressure
of the atmosphere, and prevent it from forcing its way into the annular tube
when the same is under exhaustion. It will be seen, by reference to Fig. 7, tha
there are narrow ribs or rings
which run in grooves or channels. These grooves or channels are filled wit
projecting perpendicularly downwards, an
grease or other materials, for the purpose of keeping the circulating circula
valve d perfectly lubricated. gibal

page_text: n and
y
are twO
cylinders, whose pistons are worked from the shaft
m, and at the bottom of these cylinders are valves 1 and 2 to let out the air.
and a are two small cylinders in juxtaposition with the vacuum cylinders n
and o, and the rods of the pistons of these cylinders y and x are connected with
the same beams that work the vacuum cylinders n and o.
The cylinders y and x have no valves. The cylinders n and o are worked in
the following manner :-
up
The piston t being at the bottom of the vacuum cylinder n, it is to be drawn
and a vacuum created under it, and on opening the valve v² in the pipe v,
the air which is in the part a¹ of the annular tube a passes into the vacuum
cylinder n, and is driven out of this cylinder through the valve 2 by the
pressure of the air on the piston in the cylinder a, under which a vacuum was
maintained on its being drawn up at the same time, by the same motion, and
by the same beam as the piston in the vacuum cylinder n.
The vacuum cylinder o is worked in the same manner. To put this engine
in motion (assuming the piston to be in the position shewn in Fig. 6), I
exhaust the part of the annular tube, marked a¹, by means of a small air-pump
or any other convenient contrivance; I then open the inlet valve f to admit
the pressure of the air on or against the piston b, which drives it round in the
direction of the arrows; and the vertical arm e of the piston b, acting upon the
lever arm l, as before noticed, causes the shaft m to rotate, which makes
the tappets p and q act upon the lever p* and q*, which will raise the rods
of the pistons of the vacuum cylinders o, thereby creating a vacuum underneath
their pistons, and into which vacuum the air enters through the valves v¹ and v³
When the piston has
in the pipe w from the part a² of the annular tube a.
passed the division valve g, I shut the inlet valve f and open the inlet valve f¹,
and the valves v¹ and v3 being closed in the pipe w, I exhaust the part a¹ of
the tube by the vacuum cylinders n, as before described, by the tappets p and q
acting upon the levers r and s while the piston is travelling from the inlet
valve f¹ to the division valve g¹ in the direction of the arrows, thus producing
a continuous circulating motion.
I would here observe that, if preferred, air pumps and vacuum chamber
may be employed instead of the large vacuum cylinders n and o, in which cas
the air pumps must be kept continually at work while the circulating piston
is moving round in the annular tube.
Having now described my Invention of improvements in obtaining moti
power by rotary or circular movements, and the means of applying the san
to useful purposes, I would observe, that although I have described the be
means in my power for carrying the said improvements into effect, I do

page_text: mean or intend to confine myself rigidly thereto, as they may, doubtless, ho
varied without departing from the nature and object of my Invention; I
therefore claim the use and application of a circular or annular tube, in
which a piston is made to travel, as above described, and which by means of
an annular slit or opening admits of an arm (projecting from the piston)
acting against and propelling another arm attached to a shaft, which will
communicate motion to any machinery by means of ordinary gearing.
I also claim the use of the vacuum cylinders n and o of the air engine, as
well as the small pumps which work them, and also the use and mode of con-
structing and working the travelling circular valves (attached to the pistons,
and forming part of the pistons,) which valves close the slit or opening in
the annular steam or air tubes, as above shewn and described.
In witness whereof, I, the said James Nasmyth, have hereunto set my
hand and seal, the Twenty-first day of March, in the year of ou
onbyte Lord One thousand eight hundred and fifty-six.io
di
THOMAS NASMYTH,
No. 5, Rue d'Amiens, Lille, France,
21 March 1856.
JAMES NASMYTH. (L.S.)