CERTAIN NEW METHODS OF APPLYING THE VIBRATING OR RECIPRO- CATING MOTION OF STEAM OR FIRE ENGINES TO PRODUCE A CONTINUED ROTATIVE OR CIRCULAR MOTION ROUND AN AXIS OR CENTRE, AND THEREBY TO GIVE MOTION TO THE WHEELS OF MILLS OR OTHER MACHINES
Year: 1781

page_text: of Birmingham, in the County of Warwick, Engineer, send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-fifth day of October, in the twenty-second year of His
reign, did give and grant unto me, the said James Watt, my exors, adñiors,
and assigns, His especial licence, full power, sole priviledge and authority,
that I, the said James Watt, my exors, adññiors, and assigns, should and
lawfully might, during the term of years therein expressed, make, use, exercise,
and vend, within that part of His Majesty's Kingdom of Great Britain called
England, His Dominion of Wales, and Town of Berwick upon Tweed, my
Invention of "CERTAIN NEW METHODS OF APPLYING THE VIBRATING OR RECIPRO-
CATING MOTION OF STEAM OR FIRE ENGINES TO PRODUCE A CONTINUED ROTATIVE
OR CIRCULAR MOTION ROUND AN AXIS OR CENTRE, AND THEREBY TO GIVE MOTION
TO THE WHEELS OF MILLS OR OTHER MACHINES;" in which said recited Letters
Patent is contained a proviso obliging me, the said James Watt, by an instru-
ment in writing under my hand and seal, to 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 His Majesty's High Court of Chancery within four
calendar months next and immediately after the dateof the said Letters Patent,
ás in and by the said Letters Patent, relation being thereunto had, may more
at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
James Watt, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described
and ascertained in manner and form following (that is to say):-
The fire or steam engines whose vibrating or reciprocating motions are to
be converted into rotative motions by any. or all of the five methods herein-
after described, may be constructed either upon the principles of the steam
engines called Newcomen's fire or steam engines, (which have been hitherto
most commonly used,) or more advantageously upon the principles of those
newly improved steam or fire engines of my Invention, (the sole use and
property of which was granted to.me by His present Majesty's Royal Letters
Patent, dated in the ninth year, and by an Act of Parliament made and passed
in the fifteenth year of His reign); or the said engines may be constructed in
any other manner or mode wherein a piston or any other part of the said steam
or fire engine has a vibrating, alternating, or reciprocating motion; therefore,
as for the aforesaid purpose no peculiar construction is required in those parts
of the steam or fire engines which concur in and are necessary for the
producing the power or active force of the engine and its vibratory or recipro-
cating motion, and as steam or fire engines are common and well known
machines, it is not necessary to enter into any description of them, I proceed
explain my newly invented methods of applying the vibrating or reciprocating
motions of steam or fire engines to produce a continued rotative or circular
motion round an axis or centre, and thereby to give motion to the wheels of
mills and other machines, which methods are five in number, and are described
as followeth :-
In the first of these methods I employ the power of the steam engine
either directly or by the intervention of a lever or levers, to pull, push, or
press a friction wheel or pulley against the lateral surface of a wheel fixed
obliquely upon the primary axis, shaft, or wheel which is to receive the rotative
motion, which lateral surface of the said oblique or inclined wheel is repre-
sented by the section of a hollow cylinder (A, B, C.) in the Drawing, No. 1,
Fig. 1st), cut or sawn off at the angle of sixty-five degrees to its axis, or at
any other angle which may be convenient or useful; and the said friction
wheel or pulley (J) is impelled or pulled by the power of the steam engine
against the said lateral surface of the inclined wheel (A, C,) in a direction
which is in one way parallel to the said primary axis or shaft (D, E,) of the
said obliquely cut cylinder or inclined wheel (A, C); therefore, the friction
wheel (J), commencing its motion at the lowest or nearest part (C) of the said

page_text: inclined wheel (A, C,) continues to move in the aforesaid direction nearly
parallel in one way to the primary shaft or axis (D, E,) and thereby obliges
the inclined wheel (A, C,) and the primary axis (D, E,) to turn round or
revolve on their centre until the highest or most distant part (A) of the said
oblique surface of the inclined wheel (A, C,) comes into contact with the
said friction wheel (J), at which point or time the working beam (P, P,) or
other moving part of the steam engine has moved the length of its stroke,
and is disposed to return by the common or other machinery used for that
purpose, and the inclined wheel or obliquely cut cylinder (A, B, C,) has made
one half of a revolution on its axis; and the rotative motion of the said
inclined wheel (A, B, C,) is continued in the same direction through the other
half revolution by means of the descent of the heavy arch (G) which was
raised by the power of the steam engine at the same time with the friction
wheel (J), and which during the returning motion of the working beam of the
steam engine acts upon the inclined wheel (A, C,) on the opposite side of the
primary axis (D, E,) by means of a second friction wheel (H), which is carried
by a double lever or carriage (G, F,) whose center of motion is at (K), and to
the one end of which the heavy arch (G) or any other weight is attached or
suspended, and the velocity which the matter of the wheel or cylinder (A, B, C,)
has acquired serves to continue its rotative motion past the points (A and C)
where neither the steam engine nor the weight (G) have much action upon it,
and when the point (C) has again come into contact with or has passed the
friction wheel (J), the steam engine again commences its action, and the motion
is continued as has been recited; and the mill-work or other machinery which
is required to be wrought by this machine is put in motion by the said primary
axis, or by the oblique or inclined wheel, or by means of wheels connected
with them in the usual manner. This method of producing a rotative motion
by means of a friction wheel acting against the lateral surface of a wheel
inclined to its axis, admits of many varieties in its mode of application, for
I fix the primary axis or shaft either perpendicular or horizontal, or at any
other angle of inclination to the horizon which may be required, and I use one
or more friction wheels, and I increase or diminish the angle of inclination of
the oblique wheel to the primary axis, as the case may require. As therefore I
cannot herein represent all those varieties, I have hereunto annexed a Drawing
or delineation and description of one of the best (which is applicable to the
moving of corn and other similar mills), which Drawing is delineated in its
true proportions, according to a scale of one-fourth of an inch for each foot of
the real machine, being one forty-eighth part of the real 'size'; but it must be

page_text: remembered that I make the machines larger or lesser, and vary the pro-
portions of their parts, as their uses may require. To shew the easiest method
of connecting the said new machinery with the piston of the steam or fire
engine, on whatever principle it may be otherwise constructed, I bave delineated
in red the piston and cylinder of a Newcomen's steam engine (as being the most
commonly used). And as the same mode of connection serves equally for all
the four following methods herein described, I have not repeated the Drawing
of the said steam engine, but have only delineated the parts which in these
methods connect the new machinery with the old.
My second method of producing the aforesaid rotative motion consists in
applying the power of the steam engine to pull, push, or press a friction wheel
or wheels against the external or internal circumference of a circular, oval, or
double spiral wheel fixed upon an axis or shaft, in such manner that the said
axis or shaft shall not pass through the center of the said circular, oval, or
double spiral wheel, but shall be fixed nearer to one side of the circumference
than to the other, which, therefore, I denominate an excentric wheel, and the
said action of the steam engine and of the said friction wheel or wheels upon or
against the circumference of the said excentric wheel causes it to make one
half of a revolution, and its motion is continued through the other half revolution
by the descent of a weight fixed to or acting upon the said excentric wheel or its
shaft, or acting upon another excentric wheel (fixed to the same shaft) by
means of a friction wheel or wheels. This second method also admits of several
varieties in its application, of which I have hereunto annexed a delineation of
two of the best, shewing the action of the steam engine on the external and
also on the internal circumference of excentric wheels, which Drawings are
delineated and set forth according to their true proportions by a scale of one-
fourth of an inch for each foot of their real size; but the said machines are
also made larger or lesser, and the proportions of there parts varied according
to the uses for which they are required. The excentric wheel whose external
circumference is acted upon by the steam engine by means of friction wheels
is moved as follows (sce the Drawing No. 2, Fig. 1st):-The steam engine
pulls up the frame (H, D, L,) with the friction wheel (F, G,) against the external
circumference of. the excentric wheel A, B, which causes it to revolve on its
axis towards D, until the point A of the excentric wheel comes to be in the
middle between the points of contact of two friction wheels F, G, (with the
excentric wheel, and the point B has attained the summit of its motion, then
the steam engine ceases to act, and the velocity acquired by the excentric
wheel A, B, carries its point B beyond the summit, and the gravity of the.
;

page_text: unballanced part of the excentric wheel, which is made equal to half the power
of the steam engine, or greater or lesser as may be necessary, causes the
excentric wheel to perform the other half revolution, by which motion it pulls
down the frame E, D, L, and the end (J) of the steam engine's working beam,
and the point B having past its lowest place, the engine begins to act as before.
The action of the steam engine on the internal circumference of an excentric
wheel is described as follows:-When the engine pulls up the frame D, E,
(see the annexed Drawing, No. 2, Fig. 3d,) with the friction wheel.C, the
latter is pressed against the internal circumference of the excentric wheel at
H, by which means the wheel is turned round half a revolution, and the point
B becomes the vertex; then the engine ceases to act, and the weight of the
wheel descending causes it to continue to revolve in the same direction, and
compleats the rovolution in like manner as has just been described.
My third method of producing the said rotative motion is by means of a
rod or rods D, B, (see the Drawing No. 3, Fig. 1st,) one end (D) of which
is attached or suspended to the end of the working beam of the steam
engine, and the other end (B) to any point of a wheel (A, E, B, F,) of a
circular or any other form, which wheel is fixed at one end of a shaft or
axis (C), so that by the revolution of the said wheel and the said axis (C),
the said latter point of fixture or attachment (B) shall describe a circle
round the centre of the said axis, the diameter of which circle shall be
equal to the extent of the stroke of the point of the engine's working beam,
to which the end D is attached, and the said wheel (A, E, B, F,) is made so
much heavier on one side (E, B, F',) of the centre than upon the other
side (A) that the said unbalanced weight (E, B, F,) shall havo an action in
its descent equal to one half of the power of the steam engine which works
the machine, or more or less, as required; or, in place of putting the weight
in the wheel (A, B, F,) itself, it is put upon a lever or other wheel, fixed
to the said shaft (C, C,) in any other part, or is fixed in any other manner
which may serve to make the wheel continue its motion during the return
of the piston of the steam engine; and this machine is used as follows:-
When the point or pin (B) which connects the rod (D, B,) with the wheel
is a little on either side of the lowest part of its revolution, the steam engine
pulls the rod (D, B,) and thereby obliges the wheel to make one half of a
revolution, and the unbalanced weight (E, B, F,) of the wheel, or such other
weight as acts upon it during the return of the steam engine, makes the wheel
compleat its revolution, as has been already recited in the above methods.
This third method also admits of several varieties in the mode of exccution,

page_text: for the wheel is sometimes placed so as to turn vertically (as in the Drawing)
and sometimes to turn horizontally, and also at other inclinations to the horizon
and the balancing weight. is also placed in various situations. I have therefore
delineated only one of the most simple and perfect of these methods in the
Drawing No. 3 hereunto annexed,, which is laid down by the same scale with
the other Drawings of the preceding methods; but the size of the machine
must be greater or lesser, and the proportions of its parts varied according to
its use.
My fourth method of producing the aforesaid rotative motion consists in
employing two steam engines to produce a rotative motion in one and the same
axis or shaft by any of the aforesaid three preceding methods, or by that which
is herein-after described; and in applying these two steam engines in such
manner that the second engine shall begin to act when the first engine has
made the said shaft revolve upon its axis one-third part of a revolution or
thereabouts, and consequently by the action of both the engines the shaft
makes two-third parts of a revolution, and its motion is continued through the
remaining one-third part of the revolution, by the action of a weight properly
placed, by which means the rotative motion is maintained in a more equal
manner than can be done by a single steam engine. I also apply this method
to move two seperate or distinct shafts or axles, which are connected in their
action by wheel-work or otherwise, so that they both must revolve the same
number of turns in the same time. As this fourth method must admit
of many varieties in its application to any or all of the three preceding or the
following methods, all which may be easily understood by explaining its
application to one of them, I have only delineated in the Drawing No. 4
its application to the third method, as being the most simple, and I have
laid down the said Drawing according to the same scale with the others.
The motion of this machine is explained as under. The pin (G) of the con-
necting rod B, G, (see Drawing No. 4, Fig. 2d,) having past its lowest point,
the working beam B ascends by the power of the steam engine to which it
belongs, and by its action on the pin G, through the rod B, G, causes
both the wheels and their common axis to revolve until the end of the rod
B, G, arrives at the point (C), at which time the end of the rod (A, C,)
(which is attached to the further wheel) is arrived at the point K, (that is, a
point of the further wheel directly behind K in this view,) and the centre of
gravity of the weight or heavy sides of the wheels G, J, C, has passed its
vertex or highest part at F, and begins to descend towards K, the rod B, G,
continues to act upon the wheels until it arrives at F, where it ceases to

page_text: act, and the motion is continued only by the gravity of the heavy side of
the wheels or by any other properly disposed weight, until the point C of the
further wheel has past its lowest place and comes into the position directly
behind G, when the steam engine belonging to the rod A, C, begins to act
and continues the motion until it arrives again at C, when the revolution is
completed and the rod B acts as before; the heavy sides of the wheels or any.
other weight used to continue the motion ought to be equal to one-half of the
power of one of the engines, but may be greater or lesser as suits.
My fifth method of producing the aforesaid rotative motion delineated in
the Drawing No. 5, hereunto annexed) is performed by means of a toothed
wheel E (Fig. 1st), fixed upon the end of the shaft or axis F, which is to
receive the rotative motion, which wheel E is acted upon and made to revolve.
by means of a second toothed wheel D, of an equal or greater or lesser:
diameter, which is firmly fixed to or connected with a rod A, B, (the other end,
of which is attached or hung to the working beam B, C, of the steam engine:
or is otherwise connected with the piston of the said engine,) in such manner;
that the said wheel D cannot turn round on its own axis or centre, and by:
means of a pin A, which is fixed to or in the centre of the wheel D, and
enters into a groove or circular channell in the large wheel (G, G, or by any
other proper means) the wheel D is confined, so that it cannot recede from:
the wheel E, but can revolve or turn round the wheel E without turning on
its own axis or centre, and the motion is performed as follows:-The wheel D
being nearly in the position of the prick't circle H, H, and so that its centre
shall be a little towards either side of the perpendicular line passing through:
the centre F, the steam engine by means of the connecting rod-B, A; pulls the
wheel D upwards, and as its teeth are locked in the teeth of the wheel E, and-
it cannot turn on its own axis, it cannot rise upwards without causing the;
wheel E to turn round upon its axis F; when the wheel D is raised so high:
that its lower edge is come into contact with the upper edge of the wheel E,
the engine has compleated its stroke upwards, the piston of the engine is
disposed to return, and the wheel continuing to turn round in virtue of the
motion it had acquired, it carries the wheel D past the vertex or highest.
part, and the gravity of the wheel D, or of the connecting rod A, B, or of
any other weight connected with them; causes the wheel D to descend on; the
other side of the wheel E, and thereby continues the motion it had imprest
upon it, whereby the wheel D completes its revolution round E; and when the-
two wheels. D and E have equal numbers of teeth, the wheel E makes two
revolutions on its axis for each stroke of the engine; and in order that the,

page_text: said motion may be more regular, I fix to or upon the shaft or axis F, M, L
(Fig. 2d,) or to or upon some other wheel or shaft to which it gives motion, a
heavy wheel or flyer to receive and continue the motion communicated to it
by the primary movement.
And be it remembered, that in all cases were heavy wheels or swift motions
are not otherwise necessary to the uses to which any of the four preceding
methods herein described may be applied, a flyer or heavy rotative motion should
be applied to them to equalize their motion. In Fig. 3d & 4th, I have delineated
the application of this method to a wheel C, C, fixed upon the primary axis,
and having teeth upon its inside circumference which is acted upon by the
wheel E in the manner which has just been recited, but as the wheel E has
only half the number of teeth that the wheel C, C, has, the wheel C, C, will
make only one revolution for every two strokes of the engine. The Drawings
of this fifth method are also delineated according to a scale of one-fourth of
an inch for every foot of the real size of the machine. Fig. 1st and 2d
are adapted to a stroke of six feet long, and Fig. 3d and 4th to a stroke of
three feet long; but I make the machines larger or lesser, and also make such
variations in their structure as may serve to accomodate them to their use,
as I alter the proportional diameters of the two wheels, and I place the primary
axis either horizontally, perpendicularly, or inclined, and I make the wheels of
an eliptical, oval, or other form, and sometimes in place of the wheel D, I use
a straight row of teeth or pins fix't to the connecting rod A, B, which take
hold of the teeth of the said wheel E and cause it to revolve, some point of
the connecting rod being guided by a pin moving in a groove, so as to keep the
teeth or pins always engaged in the teeth of the wheel E, and also to keep
the teeth of the wheels always engaged in another; instead of the wheel G, G,
and its groove, I use a strap of leather, or a link of iron, or other proper
material (such as is drawn at J, K, which embraces the axis M or F, and
the pin A, and connects them together and keeps them at their proper distance
from each other, and I also make the two wheels E and D without any teeth,
that D turns E by the friction of their circum-
but with rough surfaces, so
ference alone.
Be it remembered, that though I have described all these motions as
derived or produced from the motion of the end of the working beam of the
steam engine, they may also be derived from the vibrating motion of any other
part of the steam or fire engine which is found convenient; the end of the
working beam appears at present to be the best adapted for that purpose; any
or all of these methods admit of the machines being moved with rotative

page_text: motions in either direction, that is, either right-hand ways or left-hand ways
about, according as the motion is commenced in either of these directions
respectively.
In witness whereof, I have hereunto set my hand and seal, the Thirteenth
day of February, in the year of our Lord One thousand seven hundred
and eighty-two.

page_text: g. An Edge new of the two Wheels & a longitudinal one of their Shaft or Axis
A. & B. parts of the Workang Beams of the two Steam Engines. C.D.F.G. Edge news of
the wheels. HH Thar common Aris supported at H.H. A.C B.G. Reds which con
-nest the wheels to the working Biams of thar respective Engines.
Fignd Front new of the Wheel F. G. the other wheel C.1) bang hid by FG in this new!
A. B. Part of the working Brams of the two Steam Engines.
of the further wheel C.D.
A. The unnecting Rea
B.G. The connecting Rod of the nearest Wheel J.E.G
H The center of the Wheels and of thar Shaft or Aus C.J.G. The hears side of both Wheel