AN IMPROVED ROTARY ENGINE
Year: 1878

page_text: LETTERS PATENT to Emanuel Genty and Jules Deschamps, of Rouen (France)
for the Invention of "AN IMPROVED ROTARY ENGINE."
Seeled the 12th December 1910 and dated the 20th Tu 1070
PROVISIONAL SPECIFICATION left by the said Emmanuel Genty and
Jules Deschamps at the Office of the Commissioners of Patents on the 29th
June 1878.
EMMANUEL GENTY and JULES DESCHAMPS, of Rouen (France). "AN IMPROVED
ROTARY ENGINE."
The machine or rotary engine is composed of a cylindrical box or casing firmly
secured to a base or table in any convenient position.
Within the centre of the casing is a drum or central piece having a partition
projecting from its rim or periphery, which partition serves as a piston for the steam
or other motive agent to act against the piston occupying the space or steam way
between the casing and the central piece. The piston has on one face four or other
number of small plates of copper with the edges turned to bear against the side
faces and the inner periphery of the casing to ensure a steam-tight joint, the steam
pressure acting against the copper plates, which are springy for the purpose.
Diameterically opposite each other on the casing are hollow projections, within
which plates are free to slide to and fro. The inner ends of these plates bear
against the periphery of the central piece, and they alternately serve as abutment
plates or bottoms of the cylinder. The central piece is pierced at right angles to
form a steam passage from one of its arms, two of which serve as the main shaft,
and pass through stuffing boxes at each end of the casing. The steam passage
leads from an outer chamber formed by a box fitted steam-tight over one end of
the shaft; the opposite end of the shaft carries a driving pulley or other appliance
from which other machines or apparatus may be moved.

page_text: The main shaft is supported by uprights or bearings, and it has on each side of
the same a cam which govern, by means of rods and cross heads, the to-and-fro
movements of the sliding plates while the piston and central piece rotate. Apertures
are made in the casing for the escape of the spent steam, if steam be used; these
being covered and uncovered by plates or tongues which move to-and-fro under the
action of rods on the main shaft, striking levers arranged within their reach as the
rods are carried round by the shaft.
The sliding plates are each furnished underneath, with small copper plates
forming joints at grooves, which are made in the bottoms. Each sliding plate has
a longitudinal groove which admits steam into the hollow projections of the casing,
so as to have the same pressure of steam on each end, whereby little power is required
to move the plates.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Emmanuel Genty and Jules Deschamps in the Great Seal Patont
Office on the 27th December 1878.
EMMANUEL GENTY and JULES DESCHAMPS, of Rouen (France). "AN IMPROVED
ROTARY ENGINE."
Rotary engines possess theoretically possess a working superior to that of engines
with reciprocating motion, such as beam engines and others, the piston being actuated
by a continuous movement, the loss arising from the change of direction of move-
ment is avoided, and the friction occasioned by the bean, the connecting rod, the
crank, and the like being also suppressed.
In order that rotary engines should practically be really superior to ordinary
ongines it is necessary that the action of the steam should take effect without
escape, whether around the rotary piston or at any other point.
We have arrived at this result by arranging the cylinder in the form of a hollow
or ring in which the piston turns; this cylinder, which has the same thickness
throughout, is furnished at two points, diametrically opposite, with a partition or
moveable bottom, so that the steam is admitted between the moveable piston and
one of these bottoms. When a piston comes against one bottom such bottom is
disengaged to allow the piston to pass, and it closes as soon as the steam acts
between this partition and the piston.
Having thus set forth the principle on which our machine is based we proceed to
describe, with reference to the annexed Drawings, its construction; we would lay
stress to the following points :-
1st. The mechanism for deterinining at a desired time the exit and tho re-
entrance of the moveable bottoms.
2nd. That of the slide valves and parts for the inlet and exhaust of the steam.
3rd. The combination of an apparatus for reversing motion, permitting the engine
to revolve in one direction or the other.
4th. The working of the machine with a cut-off or expansion, the steam being
admitted or exhausted at the centre, the moveable part, or at the circumference,
the fixed part.
5th. The regulating of the introduction of the steam by the governor.
6th. The optional arrangement of the machine with two cylinders combined,
placed end to end, so that their pistons be fixed on the saine rod, the steam admitted
at full pressure in the first cylinder being exhausted in the second with greater
volume wherein it is expanded or cut off.
These several points, likewise the details of construction of our rotary engine, will
be well understood from the annexed Drawings.
Figure 1 is a horizontal section of the engine.
Figure 2 is a vertical section of the outer mechanism of the cylinder.
Figure 3 is a transverse section of the cylinder.
The cylinder is composed of two cheeks A, bolted on the outer cylinder B, and
each being connected with a cylinder C; these two cylinders C have between them
a very restricted space, in which works the plate D fixed on the shaft M, and which
carries the piston P. The piston is displaced under the action of the steam in the
annular space reserved between the cylinder B and the inner cylinder C.
The machine is mounted on a framework of any suitable arrangement.
The plate D must form an air-tight joint with the two edges of the inner
cylinder C, so that the steam cannot escape in the annular box in the interior of
the cylinder C; this joint is obtained by means of three well-filled circles, two of
which, a, b, are placed opposite the other, both of which rests on the plate D, and
the circle c, which forms a cover. A space d left between them permits the steam
to enter and to act as a spring, but this space could be filled by packing.
The shaft M is provided with two conduits, which serve for the admission and

page_text: escape of the steam; both these conduits open on each of the faces
piston P.
01 the
The cylinder B comprises two side valves E, which act as bottoms to the cylinder,
and become disengaged to allow the piston P to pass on which the steam acts. In
each slide valve is a small piece d', which is pressed by a spring e, serving to
deaden the shock of the slide valve against the disc D and forms the joint.
When the slide valves E nove backward they enter the boxes F, the edges of
which are furnished with grooves in which the slide valves slide; these grooves
extend into the cylinders B and C, so that the slide valves E are always supported
and resist the pressure of the steam and form a tight joint; besides, two recessos G,
contrived in the slide valves, permit the steam to circulate freely in their boxes.
The rod of each slide valve E is connected to a cross piece H, worked by two con-
necting rods.I, the pins or studs are provided with friction rollers, and are
engaged in the grooves of suitable curve of the cams J, keyed on the shaft M.
These cams are of determined form to produce at the desired time the opening and
the closing of the slide valves E.
Outwardly of the cylinder the shaft M is connected with a tube K, terminating
in a fork, and opening into the steam chest L. The exhaust steam escapes by the
box L' and the passage or conduit K¹.
On the right of the steam chest L the tubo K is surrounded by a socket N which
turns with it; it is perforated with two orifices f, f¹, which allow the steam to
pass into the passages and act as inlet ports, permitting the steam to be sent
through such or such tube, according as the one or the other of these ports is
opposite the one of the two steam passages or conduits. This socket N is connected
to the cross head g, jointed to the end of the rod n, which is also connected to the
lever X. By means of this lever the socket is displaced on the shaft, so that the
steam is admitted through the passage for through the passage f', that is to say,
on one side or the other of the piston P; but the samo moveinent should at the
same time reverse the exhaust, for this the rod n is connected by the rod o with a
second socket N', arranged in the exhaust box L'; this socket has also two orifices
p and p', which allow the steain to escape on one side or on the other of the piston,
according to the direction of rotation to be realized. In this manner when one
passage is open for the admission the other is open for the exhaust, and alternately.
This mechanisin permits of the instantaneous change of direction of movement of
the engine.
Our engine is also provided with a cut-off or expansion gear; it is composed of
the socket O, superposed on the socket N of the admission, and opens two large
channels or recesses, but this socket is fixed and connected by a rod to the
governor R. The passages for f¹ in passing under this socket are at certain
moments of the stroke hidden by the advanced part of the socket O, so that the
cut-off or expansion varies according as this socket, moveable by the governor, is
more or less advanced on the socket N.
The steam; instead of being admitted is exhausted by the driving shaft, and can
enter and escape through the cylinder, as shewn in the Drawings on a smaller scale
at Figure 4.
The engine, instead of having only one cylinder, can, as shewn in longitudinal
section, Figure 5, have two cylinders placed end to end. The steam may enter in
the small cylinder Q, at full pressure, through the circumference or through the
centre, as on the Drawing, from thence to escape into the large cylinder S where it
becomes expanded. In this case, as in the case with the single cylinder, the
machine comprising a distributing apparatus and a reversing (gear) apparatus as
herein-before described.
In our engine the piston P, shown detached in plan, Figure 6, and in transverse
section, Figure 7, is composed of moveable plates ?, ?, which form a joint on the
whole circumference; they are placed between two plates u, perfectly smooth, and
are pressed outwardly by coiled springs 8, so that the steam cannot pass from one
side of the piston to the other. Each moveable plate r is perforated by two holes t, into

page_text: which passes a screw secured to the two fixed plates u of the piston. These screws,
while permitting the free working of the plates, serve to keep the piston in place.
We have explained with reference to Figure 3 the working of the slide valves
acting as the cylinder bottoms by the cams J; Figure 8 shows on a smaller scale a
modification of this working, the slide valves being worked by means of a
lever S.
In Figure 9 the working is effected by a set bolt v, fixed on the shaft M.
We said previously that the steam could be admitted through the shaft or through
the circumference of the cylinders; we can also effect the admission and the exhaust
through the cheeks, as shewn in section at Figure 10. In this case, as in those
preceding, we can employ the steam chest already described, or it can be arranged
as seen in the Drawing. It is a disc y, keyed on the shaft M, which, in its revolu-
tion, closes, at a suitable time, the inlet passages f, f¹; for this purpose (sec
Figure 11) the disc y is furnished with orifices more or less extended, according to
the duration of admission to be effected. In this arrangement of admission of the
steam through the cheeks the inlet passage must be closed during the passage of the
piston; for this we arrange a small slide valve 2, moved by an eccentric fixed to the
driving eccentric of the slide valves E.
In these several contrivances we can arrange the steam chest inside the cylinder
as well as on the outside. We can also vary the number of pistons and slide valves
acting as bottoms of the cylinder.
Having now described the nature of our said Invention, and in what manner the
same is to be performed, we declare that we claim,―
First. The arrangement of the cylinder of the piston and of the slide valves
according to the conditions described.
Secondly. The mechanism or gear for reversing the motion, and the variable
expansion gear or cut-off by the governor.
Thirdly. The admission and exhaust of the steam through the shaft, or through
the circumference, or through the cheeks of the cylinders.
Fourthly. The combination of two cylinders joined together, the steam which is
exhausted in the first and smaller one being admitted into the second and larger
with great volume where it expands.
Fifthly. The several arrangements of cams to work the slide valves acting as
bottoms of the cylinder, according to the conditions described.
Sixthly. The several details and the whole of our engine, as herein described and
shewn.
It is optional to us to construct our rotary engine for all powers, and to vary
forms, materials, sizes of its constituent parts, &c.
In witness whereof, we, the said Emmanuel Genty and Jules Deschamps, have
hereunto set our hands and seals, this Twentieth day of December, in the
year of our Lord One thousand eight hundred and seventy-eight.
Witness,
J. ARMENGAUD, Jeune,
of Paris,
Boulevard de Strasbourg, 23,
Engineer.
EMMANUEL GENTY.
(L.S.)
JULES DESCHAMPS. (L.S.)