IMPROVEMENTS IN ROTARY ENGINES TO BE WORKED BY STEAM OR OTHER FLUID
Year: 1853

page_text: LETTERS PATENT to Thomas Walker, of Birmingham, in the
County of Warwick, Engineer, for the Invention of "IMPROVE-
Scaled the 18th February 1854, and dated the 3rd September 1858.
PROVISIONAL SPECIFICATION left by the said Thomas Walker
at the Office of the Commissioners of Patents, with his Petition,
on the 3rd September 1853.
I, THOMAS WALKER, of Birmingham, in the County of Warwick,
Engineer, do hereby declare the nature of the said Invention for
IMPROVEMENTS IN ROTARY ENGINES TO BE WORKED BY STEAM OR OTHER
FLUID to be as follows:-
The improvements relate, firstly, to that description of rotary engine
where the piston is cylindrical, and rotates eccentrically within its case;
and consist in combining with such engine a sliding stop or abutment,
whose thickness is not less or not much less than twice the distance
from the centre of the piston to the centre of the case in which it,
revolves, or whose thickness is not less or not much less than the
distance it has to travel, and in causing such sliding stop to be forced
up to the piston by steam or fluid pressure; also in causing the sliding
abutment, with its passages, to act as a valve; also to forming the

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Walker in the Great Seal Patent
Office on the 3rd March 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS WALKER, of Birmingham, in the County of Warwick, Engineer,
send greeting.
+
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of September, in the year
of our Lord One thousand eight hundred and fifty-three, in the
seventeenth year of Her reign, did, for Herself. Her heirs and suc-
cessors, give and grant unto me, the said Thomas Walker, Her
special licence that I, the said Thomas Walker, my executors,
adniinistrators, and assigns, or- such others as, I, the said Thomas
Walker, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 ROTARY ENGINES TO BE WORKED BY STEAM OR OTHER
FLUID," upon the condition (amongst others) that I, the said Thomas,
Walker, by an instrument in writing under my hand and seal, should
particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the saine
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Walker, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof (that is to say):
The improvements relate to that description of rotary engine where
the piston is cylindrical, and rotates excentrically within its case, and in
part they consist in means of combining with such engine a sliding

page_text: stop or abutment, whose thickness is not less or not much less than
twice the distance from the centre of the piston to the centre of the
case in which it revolves, or whose thickness is not less or not much
less than the distance it has to travel; such sliding stop or abutment
being forced up to the piston by steam pressure, when the engine is
being worked by steam; but when the pressure or force of other fluid
is employed, then such sliding stop or abutment is forced up by the
pressure of such other fluid. Heretofore in the construction of rotary
engines with sliding abutments, which act in each case with one edge
or end against the piston used, the abutment so used have, to the best
of my belief, been formed comparatively thin, that is to say, in thick,
ness very considerably less than equal to the distance which the
abutment lias to travel in the rotation of the piston. I would, however,
state, that in the Specification of a former Patent granted to me on
or about the Twenty-third day of February, One thousand eight hun
dred and fifty-two, I showed, as a means of working two cylindrical
pistons excentrically together on different shafts, a sliding abutment
between them of a relative thickness equal to that according to my
present improvement; but such was a divided abutment, and the
increased thickness thereof was in order that the length of abutment
between the two pistons might be uniform at all times of the revolu-
tion of the pistons, in place of employing an abutment capable of
expansion and contraction, as would have been necessary with a much
thinner abutment. I do not, therefore, in the present case, claim the use
of such abutments when used to act between two like rotating excen-
tric pistons on separate shafts, but confine myself to the adaptation of
solid abutments of a relative thickness described to work each in con-
nection with one piston only, the piston used being cylindrical, but
travelling excentrically in its case. But that the nature of the Inven-
tion, and the means by which I carry the same into effect, may be fully
understood, I will proceed to explain the Drawings annexed.

page_text: my Invention. Figure 4, is a sectional plan view of the same, taken
through the centre of the engine. Figure 5, is a vertical cross sec-
tional view, also taken through the centre of the engine. Figure 6, is
a horizontal sectional view, taken through the line 1, 1, of Figures 2,
and 5, in order more clearly to show the passages for the steam.
Figure 7, is a longitudinal section. Figure 8, is an end view, taken
within the bearing for the axis, and with one of the covers shewn to be
removed. Figure 9, is a longitudinal view of part of the engine, with
some of the parts removed. Other views show the details separately.
a, a, is the bed or frame of the engine; and b, b, are standards affixed
thereto, with bearings to support the main shaft c, in order to take the
strain off the lids or ends d', of the case d. The case d, is cast in two
pieces, to facilitate the fitting of the parts when manufacturing the
same, and also to facilitate access to the interior of the engine, when
required and they are held together by nuts and screws d², d², as
shown. e, is the piston, which is formed cylindrical, but placed excen-
trically upon the main shaft or axis c, and it is fixed thereto by a key el.
f, is the inlet pipe, and g, the ontlet pipe, for the steam or other fluid
whose power is employed, and which is controlled in passing into thic
engine to act on one or the other side of the piston by means of the
reversing slide valve ; and the steam or other fluid is now shown to
be passing in the direction of the black arrows, whilst it is passing
away in the direction of the red arrows; but this may be reversed by
the sliding of the valve, as shown by dotted lines in Figure 6. The
piston is consequently supposed to be travelling in the direction of the
arrow e²; i, being the stop or abutment for the steam or other fluid in
moving the piston; and this stop or abutment, according to one part of
the Invention, is, as shewn in thickness from , to , equal to twice the
distance between the centre of the cylinder forming the piston c, and
the centre of the case, or of the axis of the piston, by which arrangement
the stop or abutment is at all times in the revolution of the piston
acting in a direct line towards the centre of the piston, or with its plano
of contact with the surface of the piston at a tangent to that surface;
and I cause this sliding stop or abutment to be forced up to the piston
by the pressure of the steam or other fluid used; and such steam or
other fluid is admitted to the back of the stop or abutment by the

page_text: pipe j, or by other convenient means; and such extended thickness of
abutnient offers an important advantage by giving an increased surface
from 7, to, for the steam or other fluid used to act upon in keeping
the abutment to the piston. The inlet and outlet passages for the
steam or other fluid employed open into the chamber in which the stop
or abutment i, slides; and the stop or abutment is hollowed out on each
side, by which channels i, are formed for the passage of the steam or
other fluid into or from the cylinder or case; and when the piston is in
that portion of its circuit when the stop is fully in its chamber the
parts,, of the stopi, act as valves in connection with the pack-
ings k, k, to close those passages. The packings k, k, are borne
towards the abutment i, by slight springs, as is well understood; or
they may be borne up simply by the pressure of the steam; and the
steam in entering tends to keep the sliding packing , on that side the
abutment close up to the abutment, whilst the steam escaping tends to
keep the sliding packing k, on the escape side off the abutment, which
is important, inasmuch as a lead is thereby given to the exit steam.
The piston e, is also provided with end packings or shifting ends &³, by
which, as those ends wear away, they may be extended by the appli-
cation of filling picces introduced between the parts e, and e³. A
packing e, is applied along or across the outer surface of the piston,
with extended sides e, corresponding with the thickness of the stop or
abutment i. The object of these extended portions e, is to facilitate
the piston passing the edges of the recess in which the stop or abutment
slides.
In the various Figures of these Drawings I have shewn the main
axis broken, but a fly wheel will be applied thereto, and means of
communicating motion, as required and as is well understood; and
when the engine is working singly, as shown, there should be a coun-
terbalance weight applied on one side of the shaft c, to counteract the
weight caused by the excentricity of the piston. In some cases, how-
ever, I form the engine with two or more chambers d, and pistons e,
on the same axis c, in which case the pistons are so placed, as respects
their excentricity on the axis c, as to balance each other, and thus pro-
duce greater uniformity of weight and regularity of power.

page_text: I have stated one part of my improvements to consist in forming
the sliding stop or abutment used with a cylindrical piston revolving
excentrically within its case in thickness not less or not much less than
twice the distance from the centre of the piston to the centre of the case
in which it revolves; such thickness of piston will therefore vary with
the relation existing between the diameter of the piston used and the
interior diameter of its case. But that this may be clearly understood 1
have at Figures 10, 11, and 12, shown diagrams of a case with different
diameters of pistons working therein, and abutments to each varying in
thickness from, to, and in depth from, to, suitable to each
piston. Figures 13, 14, and 15, shew surface views separately of the
respective pistons shown at Figures, 10, 11, & 12, with their packings.
Figures 16, and 17, show diagrams of the piston, Figure 10, in differ-
ent positions. In Figures 5, 7, and 8, the piston is shown in different
positions of its rotation. Figure 4, shows. the piston in the same
position as in Figure 5.
Having thus explained the nature of my said Invention, I would
have it understood that I do not confine myself to the precise details
herein shewn and described; but what I claim is the arrangement and
combination of parts of rotary engines to be worked by steam or other
fluid; as herein explained.
In witness whereof, I, the said Thomas Walker, have hereunto
set my hand and seal, this Third day of March, in the
our Lord One thousand eight hundred and fifty-four.
year of
Witness,
WILLIAM BROOKES,
⚫ Patent Agent,
78, Chancery Lane.--
THOS WALKER. (L.S.)