Improvements in Rotary Gas and Oil Engines.
Year: 1896

page_text: Date of Application, 3rd Nov., 1896-Accepted, 16th Jan., 1397
COMPLETE SPECIFICATION.
Improvements in Rotary Gas and Oil Engines.
I, LOUIS GATHMANN, of 44 Lincoln Avenue Chicago, in the County of Cook
and State of Illinois, United States of America, Mechanical Engineer, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to a novel construction in a rotary gas engine of that class
employing an explosive charge as the source of power and propelling medium, as
distinguished from engines wherein compressed air, steam and analogous gases are
employed as the propelling medium, namely such gases exerting power by
expansion due to the release of pressure thereon. The object of my invention is
to provide an engine of the kind above pointed out which combines certain features
which simplify the construction and produce an effective engine.
The invention consists in the features of construction and combination of parts
hereinafter fully described and specifically claimed.
In the accompanying drawings illustrating my invention,
Figure 1 is a side elevation of an engine constructed in accordance with my
invention, with certain parts omitted for convenience of illustration.
Figure 2 is a side elevation taken from the opposite side, with certain parts
omitted for convenience of illustration.
Figure 3 is a vertical longitudinal section, taken on the line 3-3 of Figure 5.
Figure 4 is an elevation, on an enlarged scale, of the governor for controlling
the supply of oil or gas.
Figure 5 is a horizontal transverse section taken on the indirect line 5-5 of
Figure 3.
Figure 6 is a vertical longitudinal section of a modified construction embodying
my invention, and illustrating the engine constructed with a single valve.
Figure 7 is a side elevation of another modified construction embodying my
invention, wherein the valves are carried by the rotating piston.
Figure 8 is a vertical longitudinal section of the same.
Figure 9 is a fragmentary section of the valve and valve seat taken on the
line 9-9 of Figure 6, and
Figure 10 is a detail top plan view of the projecting block at the left of Figure 3, .
in which the air and oil supply passages are situated.
As before stated it is the object of my invention to simplify the construction of a
rotary gas engine and at the same time to provide for obtaining the maximum of
energy from the propelling medium. The invention relates and is confined as above
pointed out to rotary engines in which an explosive charge is employed as the
source of power, and is operated by a continuous series of explosions, and is
therefore distinctly of a different class from engines which employ air, steam or
gas acting by expansion after pressure is relieved, for my engine acts upon
a different principle, and the same conditions do not apply to both classes of
engines. By certain novel features of construction in a rotary gas engine acting
under this principle, namely, series of explosions, I am enabled to combine in a
small compass an effective and powerful engine. To attain this result I have
provided a cylinder and a revoluble piston situated within the same and between
which the chamber or channel wherein the explosive force of the' gas exerts

page_text: itself is situated. The piston is supported by a shaft mounted in bearings
outside of the cylinder and does not come in contact with the cylinder. The
said piston is set within the cylinder and fits nicely therein with a small space
intervening between the relatively movable parts to avoid friction, while the
bearings for the piston 'shaft are arranged in the curved side arms hereinafter
described. The curvature of said side arms provides for sufficient elasticity to
compensate for the expansion of the working parts of the engine caused by the
variations in temperature therein.
I also provide a construction whereby the explosion of the gas is made as
effective as possible, that is to say, I provide for the cleansing of the chamber or
channel between the cylinder and piston after each explosion, to remove all spent
and inert gases entirely before a new explosive charge is admitted, so that in each
explosion the full force of the explosive medium is obtained. By combining in a
rotary gas engine these and other features, all of which are specifically described
hereinafter, I am enabled to provide a simple and powerful device.
Referring now to said drawings, 1 indicates the base plate, and 2 and 3 upright
side plates extending upwardly from said base plate and which support the
cylinder 4 of the engine. Within said cylinder a piston 5 is situated and is carried
by a shaft 6 that extends on both sides and is mounted in bearings 7. These
bearings 7 Figures 4 and 5 are supported by curved arms 8 rigidly secured to the
side plates 2 and 3 and to said bearings 7. The piston 5 is about the same width
as the cylinder and its diameter is slightly less than the cylinder so that it can
revolve freely therein, that is to say, the adjacent faces of the piston and cylinder
do not come in contact with each other, and therefore, when the engine is working
the friction ordinarily generated between these two principal working parts is
obviated entirely and it is obvious that there is less loss of power in the engine.
The piston is guided laterally by two rings or gaskets 9, Figure 5, secured to the
cylinder and overlapping the outer edge of the piston. It will be understood, of
course, that in an engine of this kind heat is generated, also that the temperature
varies, and, consequently the size of the parts varies slightly. In view of this fact
and to preserve strictly the position of the piston within the cylinder, that is to
say, to prevent the piston from binding and causing friction, I employ the curved
arms 8 for carrying the bearings 7. These arms are of equal length and size and
are sufficiently elastic to compensate for the expansion and contraction of the
working parts of the engine, and thus under all circumstances to maintain the
bearings in their proper position concentric with the cylinder. The cylinder is, of
course, provided with induction and exhaust ports, described hereinafter, and
between the cylinder and piston a chamber or channel is formed wherein the
exploded gas is confined. This chamber can be formed by making a groove in the
face of either the cylinder or the piston and mounting the valves on either of these
parts, as shown. Across the groove extend the abutments for forming these power
Ichambers, while the side walls of the grooves are inclined or bevelled, as shown in
Figure 5, to receive the bevelled valve, all as described hereinafter.
Referring now to Figures 1 to 5 of the drawings, the said cylinder 4 is provided
at diametrically opposite points with induction ports 10 to admit the propelling
medium to the cylinder. The said ports 10 communicate with a suitable source
of supply, which in the instances illustrated consists of air pipes 11 and gas or oil
pipes 12, and the admixture of gas and air is adapted to enter the cylinder and to be
there exploded by any suitable means of ignition coming from a suitable ignition
recess. A constant supply of air under constant pressure is admitted to the air
pipes 11, and this supply of air should be in excess of the theoretical requirements of
the engine, and it can be attained by the employment of a double acting air pump
or from any other efficient source of supply. The said piston 5 and shaft 6 are
hollow Figures 3, 5 and 6 and in the sides of said piston are a series of
perforations 13,while the hollow shaft within the piston has a series of perforations 14,
Figure 3, so that a cooling medium can be forced through the shalt and piston to
cool the former.

page_text: Aa before stated the said piston fits within the cylinder and is held in place by
the rings 9 and the shafts anil bearings, and I have, provided on the face of said
piston a valve seat or groove having inclined or bevelled walls converging: toward
the centre of the piston, and at diametrically opposite points I arrange transverse
abutments 15 which divide this valve seat into two chambers 16. I make the
transverse abutments 15 wider than the induction ports 10. In this way, while the
abutments are passing the induction ports the said ports will be closed for a
moment and the mixture is confined to the mixing chamber. The admixture will
thereby be more complete, the area of possible leakage much reduced, while at
the same time the pressure within the mixing chamber is mo nentarily increased,
so that when the charge is admitted to the explosion chamber after the passage of
the abutments the desired pressure and resulting force of the explosion will be
more uniformly and economically maintained. Although in this description
I refer to two diametrically oppositely located induction ports, abutments, valves
and eduction ports, yet it will be understood that the number can vary as found
most efficient.
In the rear of the induction ports 10 are the eduction or exhaust ports 17.
Located between the ports 10 and 17 are the valve openings 18 formed in the
cylinder and through which the valves 19 extend and enter the valve seat or
chambers 16 in the face of the piston 9. The end portions of said valves entering
said valve seats or chambers 16 are bevelled on their sides to conform to the
contour of the inclined sides of said valve seat. It will be noted also that said
valves do not come in contact with the valve seats, but that a slight space intervenes
that prevents friction between these parts, as between the cylinder and the piston
abore described.
By thus arranging the principal parts so that they work without friction I am
enabled to save a great amount of power usually lost due to this cause, and
therefore make the engine more effective. Although there is a slight space
between the cylinder and piston and between the valves and piston in Figures 1
to 6, and between valves and cylinder in Figures 7 and S, or stated broadly between
the valves and the part between which and the valve there is relative rotation, yet
the space is so small that there is as has been demonstrated, no appreciable escape
of the products of the explosion, or such as to diminish the effective force of the
explosion.
I employ a mechanism, of course, for moving the valves out of the path of the
abutments as the latter approach the valves and to move said valves inwardly after
said abutments pass by, and the said valves 19 are located and arranged so that
the back pressure of the propelling medium comes against the end of the valve and
the strain or pressure thereon is not against the piston but upon the pivot of the
valve itself, and in the instance shown this is accomplished by arranging the
valve approximately tangential to the piston so that the pressure is received by
the pivot, and in this manner the piston is relieved of pressure. I thus avoid
the friction that usually takes place between the valves or movable abutments
and cylinder or piston. Consequently, by obviating this friction I am enabled
to save a large amount of power as well as prolong the life of the parts of the
engine.
Communicating with the induction ports 10 are the passages 20 for admitting the
propelling medium. These passages 20 communicate with the air supply pipe 11
through openings 21 controlled by check valves 22, while the oil or gas supply
pipe 12 communicates with the passage 20 through an opening 23 controlled by a
valve 24 operated at intervals by the engine.
The valves 19 are hung on pivots 25 extending between the upright plates of
be engine, and these pivots 25 extend through the side plate 2 and are provided
with arms or levers 26 whose free ends are located in the path of projections or
arms 27 fastened to the piston, as shown in Figure 1. The valves are normally
held at the inward limit of their movement, and resting in their seats 16, and the .
rojections 27 are so located with reference to the abutments 15 that they engage

page_text: the levers 26 to move the valves outwardly when the abutments approach the same
and to allow them to resent after the abutments pass by."
It will be seen that the ends of arms 27 strike the ends of arms 26 and turn the
pivots 25 to move the valves outwardly, and that the' valves are returned to
their normal position by springs 26 that press against feet 26 secured to the
arms 26.
The supply of air is controlled automatically in accordance with the relative
pressure on opposite sides of the check valves 22, but the supply of oil is regulated
by the movement of the piston and controlled by a governor carried thereby, as
will now be described. The valves 24 are connected through the interme livey of
links with a vibrating lever 28 mounted upon plate 3 of the engine, and an arm 29
is fastened to said fever and projects downwardly in the path of a cam disk 30
carried by the piston. The cam disk 30 has two projections 31 so located that
they strike arm 29 at the moment it is desired to open the valves 24, while the cam
disk 30 is movable upon the hub 32 of the piston and upon which it is mounted.
The cam projections 31 are bevelled on their inner sides, so that while the disk
stands at the inner limit of its movement the arm 29 will be moved to the full
extent of the projection, yet when the disk is moved outwardly by the governor
the extent of movement of the arm 29 decreases proportionally to the inclination
or bevel of the cam projections 31, and thus opens the valves 24 to a less extent.
The said governor is mounted upon the hub 32 and consists of projections 33 upon
which are pivoted bell-crank levers 34 weighted at one end and at their other ends
engaging a groove 35 in a hub projection 36 of the cam disk. Springs 37 are held
by pins 38 mounted upon hub 32 and serve to hold the bell-crank levers 34 at the
inner limit of their movement. In this way it will be seen that the supply of oil
can be regulated and is controlled automatically, and that if the speed of the engine
becomes excessive, the governor will serve to open the valves to a less extent and
regain their former position as the speed approaches normal.
It will be understood that there is a constant supply of air controlled by the
pressure on check valves 22, and that although the oil is under pressure also, yet it
is controlled by the piston and is admitted while the air is on, and I put the oil
under greater pressure than the air so that a small quantity can be quickly injected
at the proper moment.
The operation of the engine is as follows: In Figure 3 the parts are shown in
about the position they occupy just after an explosion has taken place, and the
abutments 15 are travelling from the induction port 10 to the exhaust port 17,
that is to say, the valves controlling the air and oil supplies have opened
and closed, the oil valve 24 being closed by the mechanism heretofore described
and the air valves 22 being closed by the excess of pressure between the
cylinder and said valves. When the abutments 15 reach the exhaust ports 17
the active and useful force from the exploded gases has about ceased, and it
will be noted that when the abutments pass the exhaust ports the pressure
within the cylinder decreases considerably, owing to the opening of this port, and
therefore the pressure within the air pipe 11 being maintained will overcome the
pressure within the cylinder and therefore open the air valve 22 and permit a
charge of fresh air, or what I term a scavenger charge, to enter the cylinder, and
remove the inert and spent gases. This supply of fresh air continues until the
next explosion takes place, and therefore in the meantime it will be seen that when
the swinging valve 19 opens to permit the passage of the abutment, any of the
spent or inert gases remaining will be blown out through the valve opening 18, but
as soon as the abutment passes by the valve, and the valve closes, the fresh air is
then retained within the cylinder, and as soon as the abutment passes the induction
port 10 the supply of oil or gas is admitted and the admixture becomes ignited
from the ignition recess and thus supplies another propelling charge to the
cylinder, and so on. It will be seen from the foregoing description that by
expelling from the cylinder all the inert and spent gases, and cleaning the cylinder
BO to speak; the next charge has greater force and power than if these spent

page_text: gases remained and were admixed with the fresh charge, and therefore I am
enabled to obtain a given force and power from the engine in a more economical
manner than has heretofore been accomplished. Another advantage I obtain from
allowing this fresh charge of air. to pass through the cylinder after each explosion,
is that the piston, and cylinder are cooled off to a certain extent, that is to say,
the excessive beat usually present is reduced and equalized to a certain extent by
this charge of fresh air passing through the heated parts, and the premature
explosion of the mixed gas and air effectually prevented.
:
In Figure 6 I have shown a modified construction embodying my invention,
which consists in making the cylinder with one induction port, one exhaust. port
and one valve, and in making the piston with only one abutment...The construction
and operation of this form of the device will be obvious. I have also shown in
said Figure 6 a salety or relief valve for maintaining the supply of oil at an even
pressure, which consists of a valve chamber 39 situated between the pipe 12 and
the valve 24, 'while a passage 40 leads from said valve chamber 39 to the oil
passage 23.
Above the passage 40 a relief passage 41 leads from said valve
chamber 39, and within the valve chamber 39 a valve 42 is situated and carries a
stem 43 passing out through the upper end of the valve chamber and provided
with weights 44, which can be increased or diminished in accordance with the
pressure to be maintained. The normal pressure upon the oil is sufficient to lift
the valve 42 above the passage 40 and thus permit the oil to flow to the oil
passage 23, but it will be seen that under an abnormal pressure within the pipe 12,
the valve 42 will be raised still higher and above the relief passage 41 and thus
relieve the pressure by permitting the excess of oil to flow through passage 41
back to the oil tank. When the pressure again becomes normal the valve 42
recovers its former position, as will be seen. In this way it is apparent that &
regular pressure can be maintained to feed the oil in the desired quantity.
In connection with Figure 6 is illustrated a form of oil tank that could be
employed and consisting of a tank 47 communicating by means of passage 12 with
the engine. In this passage 12 is arranged a pump 49 for forcing the oil, and the
relief passage also flows into this tank as shown.
In Figures 7 and 8 I have shown still another modified construction embodying
my invention wherein the chambers to receive the propelling charge are formed
by making a groove in the inner face of the cylinder instead of in the outer face
of the piston as above described. In this construction the valves 19 are situated
and pivoted within the hollow piston and project through valve openings 18 therein
into the groove or chambers 16 of the piston, practically the reverse of that above
described. The pivots 25 of the valves project through the side wall of the piston
and are provided with arms 26 that engage projections 46 fastened to the side of
the cylinder to cause the valves to rock on their pivots when they approach and
retire from the abutments. In other particulars the construction is similar and the
engine works in the same manner as in the first described construction.
It will be seen therefore that I provide a rotary gas engine to be propelled by
successive explosions, wherein the rotating part or piston is entirely surrounded or
enclosed by a cylinder, and between which piston and cylinder the explosion
chamber is situated, but that the piston and cylinder are not in contact with each
other and rotate without friction.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a rotary gas engine, wherein explosive charges are employed as a source
of power, a cylinder, and a piston of less diameter than said cylinder situated and
supported within the same and capable of rotation therein without contact with the
said cylinder, substantially as described.
2. In a rotary gas engine, the combination with a cylinder having induction and
exhaust porte, of a piston rotatably mounted therein, valves pivotally mounted upon

page_text: one of said parts and adapted to enter valve seats, said valve seats being formed in
the other of said parts and having inclined side walls and transverse abutments,
and said valves having inclined ends adapted to enter said valve seats, with
devices for admitting the propelling charge and for operating the valves, substantially
as described.
3. In a rotary gas engine, wherein explosive charges are employed as a source
of power, a cylinder and a piston co-operating therewith, one of said parts having
an explosion chamber and the other part having a clearance extending into the
explosion chamber, and said parts rotating without frictional contact aud a valve
or movable abutment adapted to be projected at regular intervals into the explosion
chamber to confine the explosive force, substantially as described.
Dated this 3rd day of November 1896..
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.