IMPROVEMENTS IN COMBINED GAS AND AIR ENGINES."
Year: 1867

page_text: LETTERS PATENT to Charles Denton Abel, of No. 20, Southampton
Buildings, Chancery Lane, in the County of Middlesex, Patent Agent,
for the Invention of "IMPROVEMENTS IN COMBINED GAS AND AIR ENGINES."
- A communication from abroad by Eugen Langen and Auguste
Nicol Otto, both of Cologne, in the Kingdom of Prussia.
Sealed the 31st January 1868, and dated the 3rd August 1867.

page_text: construction of slide valve there described, the following arrangement is
employed
:
The piston rod having a rack, as in the former arrangement, is guided in
its motion by means of a cross head sliding between two guides fixed on the
top of the cylinder. Upon the driving shaft is fixed a disc having a pro-
jecting boss on either side, upon which are two loose discs, between which is
bolted a toothed ring in gear with the piston rod rack; between the inner
circumference of the ring and the fixed disc is the mechanism for imparting
the motion of the toothed ring to the shaft when the former is performing its
down stroke, and for causing the ring, to turn loose on the shaft when the
piston performs its up stroke. The toothed ring has on its inner circum-
ference cam surfaces, between which and the rim of the fixed disc, also
provided with fixed or sliding cam surfaces, are small rollers, which when the
toothed ring is turned by the downward motion of the piston rod are jammed
between the cam surfaces and cause the fixed disc and consequently the
engine shaft to revolve with it; whilst when the toothed ring is turned in the
reverse direction by the upward motion of the piston rod it turns loose upon
wheel in gear
with a second
the engine shaft. The engine shaft carries a spur
spur wheel on a countershaft carrying two excentrics loose upon the same,
but fixed together in a definite, relative position. Upon this shaft is fixed a
ratchet wheel, in gear with which is a spring pawl carried by one of the
excentrics, whereby the excentrics are made either to revolve with the shaft or
to remain stationary, according as the pawl is in or out of gear with the
ratchet wheel.
The throwing out of gear of the pawl is effected by a disengaging lever,
kept.by a spring in such a position that it catches against a beak on the pawl
and throws it out of gear, and at the same time keeps it and the excentric
stationary until the lever is depressed by a stud on the piston rod during the
end of the downward motion of the latter. One of the said excentrics is
connected to a lever which in being raised by the motion of the excentric
after the end of the down stroke of the piston presses against the before
mentioned stud on the piston rod, and thereby effects the requisite raising of
the piston in order to draw in the combustible gas and air necessary for
producing the next up stroke of the engine. The second excentric serves to
work the slide valve of the engine; this is situated between the side of the
cylinder, and a cover made to fit closely against it, and also to press it closely
against the cylinder by means of springs.
This slide is arranged and actuated as follows:-When the excentrics are
stationary the slide is in its middle position, when a passage formed through

page_text: it establishes a communication between a channel leading through the side
of the cylinder to the space below the piston and an aperture in the valve cover,
which aperture is provided with a flap valve opened by any excess of pressuré
in the cylinder, but closed by any excess of pressure of the external atmo-
sphere. At the time that the slide valve is in this position the piston is
performing its down stroke, and consequently the products of the explosion of
gas and air that has previously taken place beneath it are forced out through
the said channel, passage, and aperture. When the piston arrives at the end
of its down stroke the excentrics are put in, motion by the depressing of the
disengaging lever, and the slide valve is made to move downwards, and at the
same time that it thereby cuts off the communication between the cylinder
and the atmosphere it establishes a communication by means of a recess in
its face between a second passage through the side of the cylinder and two
small passages formed in the face thereof, through which latter combustible gas
and air then pass respectively in the proper proportions through the recess of the
valve and into the cylinder, the piston being at the same time raised as above
described by the second excentric in order to allow such gas and air to flow
in beneath it. While this is taking place another passage formed through
the valve is in communication with two other passages for combustible gas
and air, and also with a burning gas jet situated in an aperture in the valve
cover. The flame from this jet consequently ignites the mixture of gas and
air passing into this passage, and while this is burning the valve rises up so
as to cut off all the before-mentioned communications and to establish a
communication between the last-named passage and the interior of the
cylinder. The flame still existing in the former consequently ignites the
charge of combustible gas and air in the cylinder, by the explosion of which
the piston is made to perform its up stroke.
Another improvement has reference to the water jacket to the cylinder.
In place of the arrangement previously described the jacket is cast in one
with the cylinder, so as to enclose both the lower part of the sides and the
bottom thereof, and the water space is put in communication by means of two
pipes with a small reservoir so that a continual circulation of the water in the
jacket and reservoir is established.
Another improvement has reference to the arrangement described in the
before-mentioned Specification for imparting the downward motion of the
piston directly to the mill shaft by means of an endless belt.
arrangement there described the upper end of the piston rod
In place of the
is formed with
two projecting cheeks, between which the belt passes, and which project
beyond the belt and there carry a roller turning on a pin fixed to the cheeks;

page_text: between this roller and the belt is a wedge having shoulders at top, by which
it rests upon the said cheeks when the piston rod is performing its up stroke,
in which position it allows the belt to pass freely between it and the piston
rod. Directly the piston rod commences its down stroke, however, the wedge
by continuing to move upward by virtue of the momentum previously imparted
to it by the piston rod is forced between the before-mentioned roller and the
belt, and thus jam's the latter tight against the piston rod, which consequently.
carries the belt down with it.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Denton Abel in the Great Seal Patent Office on
the 1st February 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane, in the
County of Middlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of August, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Charles Denton Abel, Her special licence, that me, the said Charles Denton
Abel, my executors, administrators, and assigns, or such others as I, the
said Charles Denton Abel, 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 "IMPROVE-
.MENTS IN COMBINED GAS AND AIR ENGINES," a communication to me from
abroad by Eugen Langen and Auguste Nicol Otto, both of Cologne, in the
Kingdom of Prussia, upon the condition (amongst others) that I, the said
Charles Denton Abel, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should'
particularly 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said. Charles Denton Abel, 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

page_text: statement thereof, reference being had to the accompanying Sheet of
Drawings, and to the figures and letters marked thereon, that is to say :-
This Invention has reference to certain "Improvements in Gas and Air
Engines," for which Letters Patent have already been granted to me, bearing
date the 12th February 1866, No. 434.
In place of the arrangement of mechanism described in the Specification to
the said Patent for imparting the motion of the piston rod to the engine shaft,
and for regulating the motion of the valves, as also in place of the construc-
tion of slide valve, there described the following arrangement is employed :-
The piston rod having a rack, as in the former arrangement, is guided in its
motion by means of a cross head sliding between two guides fixed on the top
of the cylinder. Upon the driving shaft is fixed a disc having a projecting
boss on either side upon which are two loose discs, between which is bolted a
toothed ring in gear with the piston. rod rack. Between the inner circum-
ference of the ring and the fixed' disc is the mechanism for imparting.the
motion of the toothed ring to the shaft when the former is. performing its down
stroke, and for causing the ring to turn loose on the shaft when the piston
performis its up stroke. The toothed ring has on.its inner circumference cam
surfaces, between which and the rim of the fixed dise, also provided with fixed
or sliding cam surfaces, are small rollers which when the toothed ring is turned
by the downward motion of the piston rod are jammed between the cam
surfaces, and cause the fixed disc and consequently, the engine shaft to revolve
with it, wbilst when the toothed ring is turned in the reverse direction by the
upward motion of the piston rod it turns loose upon the engine shaft. The
engine shaft carries a spur wheel in gear with a second spur wheel on a
countershaft carrying two excentrics loose upon the same, but fixed together
in a definite relative position. Upon this shaft is fixed a ratchet wheel, in gear
with which is a spring pawl carried by one of the excentrics, whereby the
excentrics are made either to revolve with the shaft or to remain stationary,
according as the pawl is in or out of gear with the ratchet wheel.
The throwing out of gear of the pawl is effected by a disengaging lever kept
by a spring in such a position that it catches against a beak on the pawl. and
throws it out of gear, and at the same time keeps it and the excentrics
stationary until the lever is, depressed by a stud on the piston rod during the
end of the downward motion of the latter. One of the said excentrics is
connected to a lever, which in being raised by the motion of the excentric
after the end of the down stroke of the piston presses against the before-
-mentioned-stud-on-the-piston rod, and thereby effects the requisite raising of
the piston in order to draw in the combustible gas and air necessary for pro-

page_text: ducing the next up stroke of the engine. The second excentric serves to work.
the slide valve of the. engine; this is situated between the side of the cylinder
and a cover made to fit closely against it, and also to press it closely against
the cylinder by means of springs.
This slide is arranged and actuated as follows:-When the excentrics are
stationary the slide is in its middle position, when a passage formed through
it establishes a communication between a channel leading through the side of
the cylinder to the space below the piston and an aperture in the valve cover,
which aperture is provided with a flap valve opened by any excess of pressure
in the cylinder, but closed by any excess of pressure of the external atmo-
sphere. At the time that the slide valve is in this position the piston is
performing its down stroke, and consequently the products of the explosion of
gas and air that has previously taken place beneath it are forced out through
the said channel, passage, and aperture. When the piston arrives at the end
of its down stroke the excentrics are put in motion by the depressing of the
disengaging lever, and the slide valve is made to move downwards, and at the
same time that it thereby cuts off the communication between the cylinder
and the atmosphere it establishes a communication by means of a recess in its
face between a second passage through the side of the cylinder and two small
passages formed in the face thereof, through which latter combustible gas and
air then pass respectively in the proper proportions through the recess of the
valve and into the cylinder, the piston being at the same time raised, as above
described, by the second excentric, in order to allow such gas and air to flow
in beneath it. While this is taking place another passage formed through
the valve is in communication with two other passages for combustible gas
and air, and also with a burning gas jet situated in an aperture in the valve
cover; the flame from this jet consequently ignites the mixture of gas and air
passing into this passage, and while this is burning the valve rises up so as to
cut off all the before-mentioned communications, and to establish a communi-
cation between the last-named passage and the interior of the cylinder; the
flame still existing in the former consequently ignites the charge of combustible
gas and air in the cylinder, by the expansion of which the piston is made to
perform its up stroke.
Another improvement has reference to the water jacket to the cylinder.
In place of the arrangement previously described. the jacket is cast in one
with the cylinder so as to enclose both the lower part of the sides and the
bottom thereof, and the water space is put in communication by means of
two pipes with a small reservoir, so that a continual circulation of the water
in the jacket and. reservoir is established.

page_text: Another improvement bas reference to the arrangement described in the
before-mentioned Specification for imparting the downward motion of the
piston directly to the mill shaft by means of an endless belt. In place of
the arrangement there described the upper end of the piston rod is formed
with two projecting cheeks between which the belt passes, and which project
beyond the belt and there carry a roller turning on a pin fixed to the cheeks.;
between this roller and the belt is a wedge having shoulders at top; by' which
it rests upon the said cheeks when the piston rod is performing its up stroke,
in which position it allows the bolt to pass freely between it and the piston
rod. Directly the piston rod commences its down stroke, however; the wedge
by continuing to move upward by virtue of the momentum previously
imparted to it by the piston rod is forced between the before-mentioned roller
and the belt, and thus jams the latter tight against the pistou rod which
consequently carries the belt down with it.
On the accompanying Sheet of Drawings is shown the construction of a
combined gas and air engine, having 'the before-described improvements
applied thereto. Similar letters of reference indicate similar parts in each of
lie Figures, of which Figure 1 shows a vertical section, of the engine;
Figure 2.shows a side elevation of the same with the slide valve cover
removed; Figure 3 shows a plan, partly in section; and Figures 4 to 13
show details thereof, and of various modified arrangements. The cylinder A
closed at bottom with a:cover B and open to the atmosphere at the upper end
has a piston. K with piston rod K¹ provided with a toothed rack, as shown,
similar to that described in my before-mentioned Specification. The pistou
rod K' is guided in its motion by means of a cross head T running between two
guides F, F, fixed on the top of the cylinder. The engine shaft W running
in the bearings L, L, carries besides the fly wheel R and driving pulley P.a
dise S.; on the projecting boss of this disc are on either side of the same
loose: discs S¹, between which is bolted a toothed rim Z, in gear with the piston
rod rack K. Between the inner circumference of the ring Z, and the fixed
disc S is the mechanism for imparting the motion of the toothed rack K¹ to
the shaft W when the former is performing its down stroke, and for causing
the ring Z, with discs S¹ to turn loose on the shaft when the piston performs
its up stroke.
One arrangement of this mechanism is shown at Figure 6. The toothed
rim has on its inner circumference cam surfaces, between which and the
disc S, also provided with cam surfaces, are small rollers o, which when the
toothed-rim-is-turned-in-the-direction of the full arrow jam themselves between
the cam surfaces and cause the disc S and with it the shaft W to turn 'with

page_text: the toothed rim, while when the latter is turned in the direction of the dotted
arrow no such jamming of the rollers can take place, and consequently the
rim Zo turns loose upon the shaft.
The arrangement shown in Figures 1, 5, and 7 differs only from the
foregoing in so far that the rollers o do not press directly upon the disc S. In
this case loose wedge-shaped pieces are situated between every three rollers
and the disc, upon which they slide freely when the toothed rim is turned in
the direction of the dotted arrow, but upon which they are firmly pressed by
the rollers when Z, is-turned in the reverse direction. The shaft W¹ running
in bearings I carries the two excentrics E, E¹, the ratchet wheel S, and the
spur wheel Z in gear with the spur wheel Z on the shaft W, through which
the motion of the latter is transmitted to the shaft W. The ratchet wheel S
is fixed to the shaft W' while the two excentrics, which are fixed together in
the relative positions shown, turu loose upon the same. Upon E is a spring
pawl S', by means of which the excentrics are caused either to revolve with
the shaft W or to remain stationary, according as the pawl is allowed to catch
into the ratchet wheel or is withdrawn from. the same by means of the dis-
engaging lever h¹. If this lever is depressed by the piston rod during its
downward motion the pawl S¹ catches into one of the teeth of the ratchet
wheel S and causes the excentrics to perform one revolution with. the
shaft W, after which, supposing the lever h¹ has ceased to be depressed by
the piston rod, it rises up by the action of the spring and disengages the pawl
and brings the excentrics to a standstill. The raising of the piston for the
admission of gas and air previous to an explosion is effected by the lever h
pressing against the, under side of the stud N on the piston rod, which lever
is actuated by the excentric E¹. The excentric E serves to work the slide
valve C¹; this is situated between the side C of the cylinder and the cover C,
which is pressed against the slide valve, and thereby also presses this against
the cylinder by means of the spiral springs f upon bolts f¹ passing through
the cover C2, as shown. The slide valve C¹ serves to open or close the
passages x and y in the cylinder, to allow air and gas to pass into the cylinder
through the passage when the piston has been raised, to ignite afterwards
such mixture of gas and air by means of a gas jet situated in the cover, and,
lastly, to allow the products of combustion to escape at the proper time
through the passage y.
Figures 8 to 13 serve to show more clearly the various functions which the
slide valve performs in its several positions; Figure 8 shows the face C of the
cylinder against which the slide valve works; Figure 9 shows the outer face
of the slide valve C'; Figure 10 shows the outer face of the cover C²;

page_text: Figure 11 shows a section on line 1, 1, Figure 8, with the slide valve in
middle position; Figure 12 shows a section on line 2, 2, Figure 8, with the
slide valve in its lowest position; and Figure 13 shows the same as Figure 12,
with the slide valve in its highest position. If the pawl S¹ is put out of gear
with the ratchet wheel by coming in contact with the lever the excentrics
romain stationary, and the slide valve is situated in its middle position,
Figure 11; the passage y of the cylinder is then in a line with both the
passage y of the slide and the passage y² of the cover. The latter is closed
externally by the valve v, which is opened by excess of pressure in the cylinder,
but closes against excess of pressure of the atmosphere over that in the
cylinder. When the excentrics commence their motion the slide valve moves
downwards into the position shown at Figure 12, and at the same time that
it thereby cuts off the communication between the passages y and. y² it
establishes a communication between the second passage a of the cylinder
and the passages m and n, of which the first communicates with the atmo
sphere, while the latter. communicates with a supply of combustible gas. This
communication between the passages x, m, and n is effected by the recess a
formed in the slide valve C: At the same time that this communication is
established the excentric E¹ raises the piston somewhat by means of the
lever h, and the space thus formed below the piston is filled with an explosive
mixture of gas and air. At the same time, also the passage 9 of the slide
valve C is in communication both with the air channel m¹³ formed in the side
of the cylinder and with the passage for combustible gas n¹. The gas passing
into 7 through the latter rises up to the aperture a¹ in the slide cover C³,
where it is ignited by means of the burning gas jet 12 there situated. While
it is still burning in the passage q the slide valve moves upwards into the.
position shown at Figure 15, and in thereby cutting off all the before-men-
tioned communications establishes a communication between the passages q
and a, and consequently the flame still burning in the former now ignites the
explosive mixture in the cylinder; the excentric E then raises the slide valve
slightly, and finally moves it downwards to its original middle position, after
which by the action of the lever h¹ on the pawl S the excentrics and the
slide valve come to a standstill again. At the moment of the explosion in
the cylinder the piston is thrown rapidly upwards, turning the toothed rim Zo
loose on the shaft W, and when arrived at the end of its up stroke the
pressure of the atmosphere causes the piston to descend, and at the same time
to impart such motion to the shaft W by the action of the clutch mechanism
previously described. As-the-piston arrives near the end of its down stroke
it forces the condensed products of the explosion through the passages y and

page_text: valve v into the atmosphere, and by throttling the exit of such gases more or
less by means of the cock D in the escape pipe it will be seen that the down-
ward motion of the piston may be more or less retarded, and thus a greater
or less interval of time may be made to elapse before actuating the valve for the
commencement of a fresh up stroke, whereby it will be seen that the power
of the engine will be readily regulated in the same manner as described in the
Specification to my before-mentioned Letters Patent. As the piston arrives
at the end of its down stroke it depresses the lever h¹ by means of the stud N
on the piston rod, and in thus allowing the pawl S¹ to catch into the ratchet
wheel it causes the excentrics to commence moving again, and the action of
the engine, as before described, is repeated. A water jacket X surrounding
the lower part of the cylinder and cast in one with the same, communicates
with a space formed between the cover B and a lower cover B¹ through which
'spaces cold water is made to circulate by means of the pipes r, r, communi-
cating with a cistern, the warm water being made to pass off to the cistern
through ; while the cold water enters from the same through r.
As only a
very small amount of heat is developed by the improved mode of action of
this engine, this circulation of the water is quite sufficient for cooling the
cylinder without having to renew the water for this purpose.
Figure 4 slows the improved arrangement for imparting, the motion of the
piston directly to the mill shaft. The mill shaft t has a pulley p, over which
'passes the endless strap t', which after descending vertically passes round the
pulley p¹ carried by the engine shaft W; as in the arrangement described in
ny former Specification. The piston rod K¹ is provided at the upper end with
two-projecting cheeks, between which the strap t¹ passes, and which carry on
'the inside of the strap a roller o capable of turning on the pin fi; between
this roller and the strap is a wedge having a projection at top, which when
'the piston rod moves upwards rests on the cheeks, thereby preventing it from
falling out, in which position of the wedge the strap passes freely between it and
the surface e of the piston rod. Directly the piston rod begins to move down-
wards the wedge by virtue of the momentum imparted to it by the up stroke
*forces itself between the roller and the strap, and presses the latter firmly
against the surface e, whereby the piston becomes connected to the strap and
imparts to it and consequently to the mill shaft tits downward motion. The
mechanism for actuating the slide valve, and for raising the piston before the
'commencement of the
up stroke is the same as previously described, and need
therefore not be again referred to.
t. Having thus described the nature of this Invention, and in what manner
the same is to be performed, as communicated to me by my foreign corre-

page_text: spondents, what I claim under the berein-before in part recited Letters
Patent is,
First, the before-described improved arrangement of mechanism for
imparting the motion of the piston rod to the engine shaft.
Second, the before-described improved mechanism for actuating the slide
valve, and for raising the piston before the commencement of the up stroke.
Third, the before-described improved construction of the slide valve
operating in combination with the several gas and air passages in the cylinder
and valve cover, substantially as herein-before set forth.
Fourth, the before-described improved construction of water jacket with
provision for effecting the circulation of water therein.
Fifth, the before-described improved mechanism for imparting the motion
of the piston rod directly to a mill shaft by an endless band.
In witness whereof, I, the said Charles Denton Abel, have hereunto
set my hand and seal, this Thirty-first day of January, in the year
of our Lord One thousand eight hundred and sixty-eight.