A MACHINE FOR EXPECTING AN ALTERNATING MOTION BETWEEN BODIES REVOLVING ABOUT A COMMON CENTRE OR AXIS OF MOTION; ALSO CERTAIN ADDITIONAL MACHINERY OR APPARATUS FOR APPLYING THE SAME TO MECHANICAL PURPOSES
Year: 1825

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOEL
LEAN, of Fish Pond House, near Bristol, Gentleman, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Thirtyeth day of July, One thousand eight hundred and
twenty-five, in the sixth year of His reign, did, for Himself, His heirs, and
successors, give and grant unto me, the said Joel Lean, His especial licence,
that I, the said Joel Lean, my exors, adñors, and assigns, or such others as I,
the said Joel Lean, 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 lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed,
and also in His said Majesty's Colonies and Plantations abroad, my
Invention of "A MACHINE FOR EXPECTING AN ALTERNATING MOTION BETWEEN
BODIES REVOLVING ABOUT A COMMON CENTRE OR AXIS OF MOTION; ALSO CERTAIN
ADDITIONAL MACHINERY OR APPARATUS FOR APPLYING THE SAME TO MECHANICAL
PURPOSES;" in which said Letters Patent is contained a proviso obliging me,
the said Joel Lean, 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
inrolled in His Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said in part recited Letters Patent,

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Joel Lean, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are particularly described
and ascertained in and by the Drawings hereunto annexed, and the following
description thereof (that is to say):
My said Invention consists,―
First, in certain machinery by the means of which any number of bodies
are made alternately to approach each other, and again to recede, while they
at the same time continually revolve about a common centre or axis of
motion; and,
Secondly, in certain machinery for applying the said compound motion to
some mechanical purposes.
Referring to the Drawing accompanying this Specification, Figs. 1
and 2 shew an arrangement of two elliptical and two circular wheels, or
of four elliptical wheels, for producing an alternating and revolving
motions. C, T, B, R, and B, G, A, Q, Fig. 1, are two ellipses or elliptical
wheels, having their respective centres of motion in the foci E and D;
and IT HR, H G F Q, are two circles or circular wheels, the centres
of which are E and D, and the diameters of which are equal to the transverse
axis C, B, and B, A, of the ellipses; also the wheels CT BR, I THR,
are firmly fixed on the same axis, while the wheels B, G, A, Q, and H, G, F, Q,
are unconnected with each other. This arrangement being made, let the
wheels be caused to revolve about their axes E and D, while their peripheries
are made to act on each other by the means of teeth or otherwise, and from
the properties of the ellipses it is known that the peripheries of the ellipses, as
well as those of the circles), will touch cach other throughout the whole of
the revolution, and that the point of contact will be always in some part of the
line C, A, passing through the foci. Those elliptical wheels will, therefore,
mutually act on each other with the same mechanical correctness as if they
had been circles; and by tracing the effects produced by the revolution, it will be
found that when the point of contact is in the semi-ellipse R, B, T, or Q, B, G,
the elliptical wheel B, G, A, Q, will revolve more slowly on its axis than the
circular wheel II, G, F, Q, and that when the point of contact is in the semi-
ellipse T, C, R, or G, A, Q, the elliptical wheel B, G, A, Q, will turn faster
round its axis than the circular wheel II, G, F, Q, and that when the points
T and G, or R and Q, (which are the extremitics of the conjugate axis of the
ellipses), are in contact, the wheels will all revolve will equal velocity; and if

page_text: while two extremities of the conjugate axis are in contact any two coincident
lines be drawn from the centre of motion D, the one in the ellipse and the
other in the circle, those two lines will, while continually revolving about that
centre, alternately recede from and approach to each other, and yet one will
never pass beyond the other. If the line D, G, be drawn from the focus or
centre of motion to the extremity of the conjugate axis, the double of the
angle G, D, B, will be a measure of the angular space described by any radius
in the ellipse, while the point of contact is passing through the arc Q, B, G,
and the double of the angle G, D, A, will be a measure of the angular space
described by any radius in the circle during the same time, and the contrary
takes place while the point of contact is passing through G, A, Q. If instead
of the circles two ellipses W X V, W Y Z, be substituted, equal and
similar to the former, but lying in the opposite direction, like effects will be
produced, but to a greater degree. The doubles of the angles L, D, B, and
L, D, A, will then be the measures of the angular spaces described, K, L,
being perpendicular to the transverse from the other focus K. This latter
arrangement of four equal and similar elliptical wheels is represented in
Figure 2, where A and B are the two wheels fixed on the same axis, and the
axis of C passes through that of D. For the better understanding of the
proportions to be observed in constructing the wheels, I have supposed
F, F, F, &c., to be six equal arms fixed on the axis of the wheel C, and
G. G. G, &c., the same number fixed on the axis of the wheel D, the former of
which being, for the sake of distinction, bounded by parrallel lines, I shall call
vancs, and the latter, which for the like reason become smaller as they
approach the centre, I shall call sectors. If now the thickness of one
vane and one sector be equal to 24 degrees, measured on the periphery
of the circle F, G, F, G, and if the proportions of the wheels be such that
their tranverse axes are to the conjugate in the ratio of one hundred thousand
to ninety-nine thousand six hundred and eighty-nine, or about one thirtieth
part of an inch longer upon every foot, then, if the wheels be made to revolve
about their axes, the vanes and sectors will approach each other until they
are nearly in contact; and the revolution still continuing the same way, they
will again separate and approach those on the other side, thus passing over the
intermediate space twice in each revolution. From what has been said it will
be perceived that the eccentricity of the wheels must bear a certain proportion
to the number of vanes and sectors, and also to their thickness, in order that
each vane may approach within a proper distance of its adjacent sector.
The following table exhibits the proportions to be observed in certain cases,
the transverse axis being 1, and the breadth of one vain and one sector, with.

page_text: ,05255
,03935
,02995
,0229
Difference of diameters in inches, the transverse being one foot,-
,77712 about
,27396
,12672
+
"
"
}
,06648 " I'S
,03732
" 30
,02148
" 30
"
,0126
And in general divide forty-five degrees by the number of vanes, and from
the quotient subtract one eighth part of the breadth of one vane and one sector,
together with the space to be included as above expressed in degrees, one half
the natural tangent of the remainder will be the distances between the centre
of motion and the centre of the wheel, from which the conjugate diameter may
be easily found. On reference to the last column in the foregoing table it will
be seen that by increasing the number of vanes the eccentricity and difference of
the diameters of the wheels may be diminished to any degree we please, and
therefore if tho wheels be made circular, we may, by taking a sufficient number
of vanes and sectors, and placing the centres of motion of the wheels at a pro-
per distance from the centres of the wheels themselves, reduce the inaccuracy
arising from the circular shape to any degree required. It is also evident, that
although an arrangement of four wheels only is described above, yet a similar

page_text: effect may be produced by a greater number than four; but a particular
description of a machine with four wheels being given, the arrangement and
proportions to be observed in constructing a machine with more than four
may be thence found.
Having explained my method of giving to the same bodies a rotatory,
and at the same time a reciprocating or alternating motion, and how to find
the proportions to be observed in constructing elliptical wheels for that
purpose, I shall proceed to shew how the same may be applied to me-
chanical purposes. If the circle F, G, F, G, &c., Fig. 2, be supposed to be
the section of a cylinder, the whole extent of which, in length, is equal to the
length of the vanes and sectors in the same direction, it is evident that, by
causing the wheels to revolve, the contents of the cylinder will be twice dis-
charged in each revolution of the wheels, and therefore, by a proper adapta-
tion of pipes and valves, a current of water, or blast of air, or any other fluid
which the cylinder contains, would be produced. And, on the other hand, if
there be introduced into the cylinder water, steam, or other fluid, tending by
its pressure or expansive force to separate the vanes and sectors, a continued
rotatory motion of the wheels may be affected. Figures 3 to 12 inclusive are
different views and sections of a steam engine on this construction, the arrange-
ment of the several parts of which may be varied according to circumstances.
Fig. 3 is an elevation, as seen from the end next the wheels. Fig. 4, an
elevation from the end next the nozzle. Fig. 5, a side view. Fig. 6, a plan
or view from above. Fig. 7, the axis. Fig. 8, the vanes separated from the
axis. Fig. 10, a transverse section of the cylinder and sectors. Fig. 9, a
transverse section through the cylinder, the axis and vanes being in their place.
Fig. 11, a longitidinal section through the the whole engine. Fig. 12, a
section of the nozzle and regulating cock. The whole of the engine may be
enclosed in a steam case A, B, C, D, which is intended to be kept full of steam
from the boiler by means of the steam pipe E. If the case be not used the
steam pipe must be extended to that part of the nozzle where the regulating
cock h is placed. In all the Figures the same letters are made to refer to the
same parts. G is the cylinder, on one end of which is fixed the wheel a, and
consequently this wheel and the cylinder revolve together; the wheel b is fixed
on the axis, and the other two wheels are fixed on the shaft c, f. Within the
cylinder are fixed the sectors, as seen at Fig. 10, and the vanes are fastened
on the axis, as shewn at Fig. 9. The inside of the cylinder, as also the part
of the axis between the vanes, must be as smooth as possible, and the vanes
and sectors must be made to fit the cylinder steam-tight, which may be done
either by packing their edges in the manner of pistons, or by fitting them to

page_text: their places by grinding as cocks, and for this purpose the inside of the
cylinder may be made conical, as is represented in Fig. 11. The ends of the
cylinder must also fit the axis so as to be steam-tight. Round the axis Fig. 7
are two channels m, n, which, when the axis is put into its place in the vanes,
Fig. 8, form two passages for the steam all round the axis, and admit it into
the cylinder on either side of the vanes. The axis at the end e terminates
conically as a cock, which fits steam-light into the nozzle g, in which cock are
two apertures o, r, Figs. 7 and 11, opening into two passages o, p, r, s, which
convey the steam to the channels m, n, from whence it passes into the cylinder.
These passages are seen in section Fig. 9, as also the channel n, and the aper-
tures by which the steam passes from it into the cylinder. The apertures from
the channel m admit the steam into the cylinder on the other side of the vanes.
On the edges of the vanes and sectors may be grooves, as seen in the different
sections, which, by means of the passage d, k, Fig. 11, may be kept always full
of oil. The regulating cock h, in the section Fig. 11, is shewn in the position in
which it is placed to stop the engine. By turning this cock either way one
quarter of a revolution, the steam will be admitted into the cylinder through
the end of the cock, and will pass off by the opposito end and through the
exhaustion pipe F. If condensation be used, and it be required to blow
through the engine, draw back the regulating cock by means of the screw i,
when the steam will pass through the exhaustion pipo F into the condenser in
the ordinary way. To set the engine to work after the vaccuum is formed; no
more is necessary than to turn the cock h one fourth part round, either to the
right or left hand, according to the direction in which the engine is required to
revolve. To stop the engine, put the regulating cock in the position shewn,
Fig. 11; to work backwards set the cock in the position opposite to that in
which it was before placed. A rotatory motion being thus given to the shaft
c, f, (which passes through a stuffing box in the side of the steam case, when
a steam case is used), the same motion is communicated by means of this shaft
to any other apparatus connected with it. By what was said above in explain-
ing the constructions of the wheels, it will be perceived that there are two
points in every revolution in which the engine is without power, and therefore
if but one cylinder is used, a fly wheel, or some other contrivance, will be
required to give the engine impetus; but in case of two cylinders being used,
they may be so connected with a common shaft as to make the action nearly
uniform. This arrangement is shewn in Fig. 13. -
In conclusion, I may add, that in the construction of an engine I do not limit
myself to the particular shape and arrangement of parts represented in the
Drawings accompanying this Specification, but that I claim under this Patent.

page_text: the exclusive right of making and using a rotatory engine, which may be worked
by the means of water, steam, gas, or other fluid, or by which a current or
stream of water, air, or other fluid may be effected, to the revolving parts of
which engine an alternating motion is given by the means of four or more
wheels, as herein-before described.
the exclusive right of making and using a rotatory engine, which may be worked
by the means of water, steam, gas, or other fluid, or by which a current or
stream of water, air, or other fluid may be effected, to the revolving parts of
which engine an alternating motion is given by the means of four or more
wheels, as herein-before described.
In witness whereof, I, the said Joel Lean, have hereunto set my hand
and seal, this 30th day of December, One thousand eight hundred