CERTAIN IMPROVEMENTS IN ROTATORY STEAM ENGINES
Year: 1855

page_text: LETTERS PATENT to Rudolph Bodmer, of 2, Thavies Inn, Holborn, in the
City of London, for the Invention of "CERTAIN IMPROVEMENTS IN ROTATORY
STEAM ENGINES."-A communication from Mr. Grainicher, of Natchez,
Mississippi, United States of America.
Sealed the 30th October 1855, and dated the 2nd August 1855.
PROVISIONAL SPECIFICATION left by the said Rudolph Bodmer at
the Office of the Commissioners of Patents, with his Petition, on the
2nd August 1855.
I, RUDOLPH BODNER, of 2, Thavies Inn, Holborn, in the City of London, do
hereby declare the nature of the said Invention for "CERTAIN IMPROVEMENTS
IN ROTATORY STEAM ENGINES," (a communication,) to be as follows:-
The improvements which have been communicated to me relate to certain
contrivances having for their object to allow the piston of that kind of rotatory
steam engine in which the piston barrel is concentric with the cylinder, to
perform a complete revolution without prejudice to the proper and regular
working of the engine. One of these contrivances consists of a shaft (which for
greater facility of description I shall call A) working in suitable bearings at
cach end, and which is provided longitudinally with six ribs, wings, or feathers,
reaching internally from one end of the steam cylinder to the other. Two of
these feathers, placed diametrically opposite to each other, are each fitted with
two packing bars, similar to those described in the Provisional Specification

page_text: accompanying the Petition of Samuel Grainicher for Letters Patent, No. 1048,
and dated the 9th day of May 1855, one set of which packing bars rest upon
and press against the cylindrical barrel to which the piston is affixed, (and
which also is placed upon a shaft working in bearings at each end outside the
cylinder), thus dividing that portion of the cylinder into which the steam enters
from that whence it escapes through the off-steam port. Every time the piston
has arrived within a short distance of the termination of its course, the shaft A
is, by means of cams, excentrics, or other similar mechanical contrivances in
connection with rods, levers, or cranks and stops, which receive their motion
from the piston barrel shaft, made to perform one half of a revolution; and
whilst it does so the piston passes through the space between the feathers on
the shaft A, by which time the steam valves, which may be of the ordinary
construction, will have allowed the steam on the exhaust side to escape into
the atmosphere or condenser, and be in a position to admit a fresh supply of
steam to the opposite side of the piston. The feathers on the shaft A are
accurately turned on the circumference, and fit into a cylindrical steam chamber
immediately over the piston barrel; and the two feathers which are placed on
each side of that which is fitted with the packing bars are each pressed upon
by a packing bar fixed to the upper portion of the steam chamber near the
steam ports, so as to prevent all communication between the admission and
exhaust side of the steam cylinder, except during the very short space of time
that the shaft A perform its half turn. Another and more simple contri-
vance for effecting the same purpose consists in a moveable partition or
slide plate, which divides that portion of the steam cylinder into which the
steam enters from the one from which it escapes through the off-steam port.
When the piston has nearly completed its revolution, this slide plate is made
to withdraw so as to allow the piston to pass, and immediately after it has
passed the slide plate advances again into its former position. The slide
plate may be moved by means of cams or excentrics of the required lift,
receiving their motion from a wheel segment cast or fixed on the ends of the
piston barrel, or by cams or excentrics connected with levers or rods, or by
other similar well-known mechanical means.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Rudolph Bodmer in the Great Seal Patent Office on the
2nd February 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RUDOLPH
BODMER, of 2, Thavies Inn, Holborn, in the City of London, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of August, in the year of our 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 Rudolph Bodmer, Her special licence that I, the said Rudolph Bodmer,
my executors, administrators, and assigns, or such others as I, the said Rudolph
Bodmer, 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 "CERTAIN IMPROVEMENTS IN ROTATORY
STEAM ENGINES," (a communication from Mr. Grainicher, of Natchez, Missis-
sippe, United States of America,) upon the condition (amongst others) that I,
the said Rudolph Bodmer, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly 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.
NOW KNOW YE, that I, the said Rudolph Bodmer, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement (that is to say):-
The improvements which have been communicated to me relate to certain
contrivances having for their object to allow the piston of that kind of rotatory
steam engine in which the piston barrel is concentric with the cylinder, to per-
form a complete revolution without prejudice to the proper and regular working
of the engine.
In order that this Invention may be better understood, and more readily
carried into effect, I will proceed to describe the same, reference being had to
the annexed Sheet of Drawings, and to the letters and figures of reference
marked thereon.
Fig. 1 is an end view, Fig. 2 a transverse section, and Fig. 3 a longitu-
dinal section, of a rotatory steam engine, to which one of these contrivances
is applied. This consists of a shaft A, working in suitable bearings at each
end, with two bushes B fixed upon it, which pass through stuffing boxes (see
Fig. 3). The shaft A is furnished with six ribs or feathers A', A2, A3, A4, A5, A6,
reaching internally from one end of the steam cylinder to the other, being
accurately turned on the periphery, and fitting into a cylindrical steam chamber

page_text: immediately over the cylinder. The feathers A & A are placed diametri-
cally opposite to each other, and each is fitted with a pair of packing bars a,
similar to those described in the Specification of Letters Patent, No. 1048,
and dated the 9th day of May 1855. During the time that the piston C'
passes from the position indicated by the dotted line 1, Fig. 2, in the direction
of the arrow, to the position indicated by the dotted line 2, the packing bars
attached to the feather A¹ rest upon and press against the piston barrel C,
which is also fixed upon a shaft C, working in suitable bearings at each end.
At the same time the feathers A & A are pressed upon by packing bars a,
fixed to the segment D (sce Fig. 2), and thus that portion of the cylinder into
which the steam enters is completely separated from that whence it escapes
through the off-steam port.
Every time the piston passes from the position 2 to the position 1, the shaft
A is, by a mechanism which will be hereafter described, caused to perform one
half of a revolution. By the time that the first quarter of a turn has been
performed, the ribs A¹ & A will be in a horizontal position, and completely
cut off all communication between the steam ports and the steam cylinder.
At the same time room will have been made for the piston to pass through
the space between the ribs A* & A'; and on the piston again arriving at the
position 1, the feathers A' & A will have changed places; the steam on the
exhaust side of the piston will have escaped through the port 3, and the valves
will be in a position to admit a fresh supply of steam through the steam port 4.
The curved plate E serves the purpose of compelling the steam to press upon
the outer surface of the packing bars a, on the segment D.
The mechanism by means of which the shaft A receives its motion is as
follows: On the piston barrel shaft Ca disk F is keyed (see Figs. 1 & 3),
a portion of whose circumference is armed with four teeth F', and every time
the piston arrives in the position indicated by the dotted line 2, the teeth F
take into the pinion G of eight teeth keyed on the shaft A, which is thereby
compelled to make one half of a revolution, as already explained. In order
that during the passage of the piston from position I to position 2, the shaft A
may be kept stationary, a disk H is further keyed on the end of the shaft A,
beyond the pinion G. The disk H is furnished with two notches 5 & 6, placed
diametrically opposite to each other. Whilst the shaft A has to remain in the
position in which it is represented in Fig. 2, the head J' of the stud J, which
passes through and is fixed to the guide bar K, takes into the notch 5 (see
Figs. 1 & 3). This bar K is guided by the eye-bolts L, and at its lower extremity
it is provided with a guide pin M, which takes into the groove 7 of the cam N,
which is keyed on the piston barrel shaft C², its centre line corresponding with

page_text: that of the piston. By the time therefore that the piston will have arrived in
the position indicated by the dotted line 2, the head J' will have been released
from the notch 5; and on the shaft A having completed its half turn, the
notch 6 will have changed places with the notch 5, and the head J' will have
dropped into it, thus again securing the shaft A in its normal position. For a
detached view of the disk H, and guide bar K, see Fig. 4. To admit of the
passage of the ends of the shaft A, the guide bar K is provided with a slot, as
seen in Fig. 1. Simultaneously with the motion of the guide bar K, just
described, the valve O is, during the passage of the piston from the position 2
to the position 1, caused to close the port 8, by means of the rod P, and the
bell-crank lever Q, the arm Q¹ of which is provided with a slot, into which the
end of the stud J takes, for the purpose of removing the steam pressure from
the shaft A. It will be observed, on reference to Fig. 3, that the mechanism
above described is symmetrically applied to both sides of the engine.
Fig. 5 is an end view, Fig. 6 a longitudinal section, and Fig. 7 a trans-
verse section, of parts of a rotatory steam engine, to which another contrivance
for effecting the same purpose is applied. To the piston barrel shaft C² (sec
Figs. 5 & 7) a disk F is keyed, a portion of whose circumference is armed
with eight teeth F¹, and every time the piston arrives in the position indicated
by the dotted line 2, the teeth F take into the pinion G, which also is fur-
nished with eight teeth. During the time therefore that the piston moves from
the position 2 to the position 1, the pinion F will be compelled to perform
a whole revolution. And as the shaft of the pinion F is furnished with a
short crank H, which is connected with the slide plate J (see Figs. 6 & 7), by
means of the standard K, the link L, and the studs L' & L, the slide plate J
will, during the first half turn of the pinion F, be raised, so as to allow the
piston C' to pass (see Fig. 6), and then again lowered into its former position
(see Fig. 7). The slide plate J may also be provided with packing bars a, by
means of which it is kept steam-tight. It will be seen, on reference to Fig. 6,
that this mechanism also is symmetrically applied on each side of the cylinder,
as in the former case. Other combinations of mechanism, such as levers and
canis, may be used instead of the wheel segment and pinion for actuating the
shaft A, described with reference to Figs. 1, 2, & 3, and the slide plate J,
described with reference to Figs. 5, 6, & 7. The slide valve and the mode of
working it forming no part of the improvements, I have omitted all descrip-
tion of it; nor have I, for the same reason, shewn it at all in Figs. 5, 6, & 7
of the Drawings. The framing of the engine has likewise been omitted as not
essential.
Figs. 8, 9, & 10 represent respectively, in side view, end view, and top view,

page_text: how, in the engine described with reference to Figs. 1, 2, & 3, the packings a
are applied to the piston barrel C, so as to ensure its tightness against the ends,
and against the internal surface of the cylinder, and also against the piston
barrel shaft C². The piston barrel C is partly hollowed out at x, x, on both sides
in a direction corresponding with the centre line of the piston C¹, in such a
manner that that portion of the metal which is left assumes a shape similar to
the upper part of the piston, forming two inclined planes, to which the packing
bars a are attached in a similar manner as to the piston itself.
Figs. 11 & 12 are detached views of one end of the cylinder, shewing the
packing bars a as applied to effect a steam-tight fit between the piston barrel
and the cylinder ends in a line with the packing bars of the feathers A¹ or A².
A triangular bar of metal is screwed into the recess x, x, (see Fig. 12,) of
the cylinder end; the packing bars a are fixed to it, as in the cases already
described, and press against the piston barrel.
Having thus stated the nature of the Invention intended to be secured
to me by the before-mentioned Letters Patent, I wish it to be understood
that I claim,-
Firstly, the application of the shaft A, and of the slide plate J, for the
purpose of affording a periodical passage to the piston, and at the same time
separating that portion of the cylinder into which the steam is admitted from
that by which it is allowed to escape, substantially as described with reference
to Figs. 1, 2, & 3, and with reference to Figs. 5, 6, & 7 of Drawings.
Secondly, the combination of the shaft A with the steam valve O, by means
of the cam N, the guide rod K, the bell-crank lever Q, and the rod P, for the
purposes described with reference to Figs. 1, 2, & 3 of Drawings.
And, thirdly, the application of the packing bars, described in the Specifi-
cation of Letters Patent No. 1048, and dated the 9th day of May 1855, to
rotatory steam engines.
In witness whereof, I, the said Rudolph Bodmer, have hereunto set my
hand and seal, this Second day of February, in the year of our Lord
One thousand eight hundred and fifty-six.
RUDOLPH BODMER.
(L.S.)