provements in Gas Engines.
Year: 1894

page_text: Date of Application, 11th Dec., 1894-Accepted, 12th Jan., 1895
COMPLETE SPECIFIC
Improvements in Gas Engines.
I, GEORGE CROYDON MARKS, of 18 Southampton Buildings, London, W.C.
Engineer, (a communication from Feodor Hirsch, of Steinway, Queen's County,
Long Island, New York, in the 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:-
My invention is an improvement upon the form of gas engine set forth in my
English Patent No. 13,333, of July 10th, 1894, in which the pistons, connecting
rods, rock shafts, pitmen, and cranks are arranged in a central plane of action,
coinciding with that of the longitudinal axis of the power cylinder. In said prior
Patent a triple wristed arrangement of cranks is resorted to, one of the pitmen is
bifurcated, and the crank webs are counterweighted to balance the extra weight
of the bifurcated pitman. This renders the parts heavier than is desirable in
small engines, especially those designed to be portable.
My present invention consists in the special construction and arrangement of
parts herein described and claimed, whereby I obviate the above stated objections,
and at the same time simplify and cheapen the construction of the engine as a
whole.
Thus I am enabled to dispense with one wrist-pin and web, with the bifurca-
tion of one pitman, and the counterweighting of the webs to compensate therefor,
lightening the engine and attaining a more perfect balance of parts and admitting
of a higher speed with a given power, as well as simplifying and cheapening the
construction without impairing the advantages attained by the use of opposed
In the
cylinders, pistous &c., arranged in substantially the same plane of action.
present case what may be designated as this common plane of action is coincident
with the central plane of the comparatively thin web which connects the two
cranks, wrist-pins, and the power cylinders are practically one and continuous.
But there are important advantages in constructing the cylinders separately,
and in joining them by a trunk or section. The difficulty and cost of boring the
long single cylindrical interior surface is avoided; the parts are interchangeable
and easily separated or replaced; and the central section or trunk portion also
affords convenient means for arranging and constructing the inlet and discharge
valves and passages in a simple and effective manner.
.
In the accompanying drawings,
Figure 1, is a front elevation of my improved engine;
Figure 2, is a plan thereof;
Figure 3, a rear elevation;
Figure 4, a view of the under side of the engine;
Figure 5, an end elevation;
Figure 6, a sectional elevation on plane of line x, x, Figure 1;
Figure 7, a vertical longitudinal section taken upon plane of line y, y, Figure 2 ;

page_text: Figure 12, a section showing the exhaust valve;
Figure 13, is an enlarged view of the relief valve mechanism;
Figure 14, is an enlarged view, partly in section and partly in elevation taken
at right angles to, Figure 13, and showing the connection of the governor with the
relief valve cam and mechanism.
Figure 15, is a view showing the relative timing of the relief valve cam, and the
exhaust cam.
The frame-work A, consists of two vertical members, upon and between which
the other parts are mounted. Brackets a, a, support the cylinders B, which are
formed with the standards b, the flanges of which 6, are secured to the brackets a.
The inner ends of the cylinders B, are secured to the central section or trunk C,
the inner ends of the cylindrical chambers opening into the rectangular central
chamber c.
The longitudinal axes of the cylinders B, do not coincide, the
difference being equal to that between the centers of the two pitmen connected
with the crank, as will be seen by reference to Figure 4. The difference in this
alignment of the cylinders is compensated for by the central chamber C, in the
trunk. C, which chamber c, is either inclined as shown in Figure 8, or is made of
sufficient length and size to include both cylinder openings. The cylinders B, and
the central trunk C, are provided with water jackets or chambers c', b², communi-
cating with each other and affording a circulation of cooling liquid in the usual
manner.
Each cylinder B, is provided with a trunk piston D, which is directly connected
in each case by a swinging piston rod d, to the upper end of a rock lever E,
pivotally supported in bearings a', at the ends of the frame A. The lower ends
of the rock-levers E, are connected with the crank wrists g, of the duplex crank G,
by pitmen F. The duplex crank G, interposed centrally in the shaft H, consists
of the two side webs g¹, g', the wrists g, g, and the central web 3, which connects
said wrist pins. It will be noticed that the two cranks are divided or separated a
distance apart equal only to this central web g³, so that the centers of the pitmen F,
rock-levers E, piston rods d, pistons D, and cylinders B, approximate each other.
In fact as far as practical results are concerned they may be considered as situated
and working in the same plane, the slight variation between the cylinders not
affecting the results attained by my form of engine as set forth in my prior
Application herein before referred to.
The power shaft H, is provided with the usual pulley h, and fly-wheel h', at one
end, and at the other or front end with the pinion 2. This pinion 2, meshes into
a spur gear I, upon the front end of the cam shaft J, which extends above and
parallel to the power-shaft H. The spur-wheel I, is twice the diameter of the
pinion, so that the cam shaft J, makes only one revolution to two of the power-
shaft.
The
The gear I, is formed with the governor K, which controls the position of the
relief-valve cam L. The governor K, consists of the weighted arms k, pivoted at i,
to brackets upon the wheel I, and of smaller arms k¹, which engage with recesses 1,
in the hub of the cam L. Thus when the speed of the engine, exceeds a prescribed
number of revolutions, the cam L, is drawn forward towards the wheel I, thereby
bringing the eccentric portion of the cam under the cam bearing arm m.
cam bearing arm m, is pivoted to a stationary part of the machine m', and is
formed with the arm m², so that it constitutes practically a rock-lever. The arm m,
is made of comparatively thin elastic material, so that should it encounter the side
of, the eccentric portion 1, of the cam L, as the latter is drawn under it, it
will yield sufficiently to prevent injury or delay until the continued rotation of the
cam L, allows it to spring back into position, in line with the eccentric portion
which will then rock the lever m, m², upward. Seated in the end of the arm' m²,
is a rod m³, which is constantly pressed downward by the spring m. The upper
end of the rod m³, is connected to the crank arm m³, by which the valve N,.is
opened or closed. When the lever m, m2, is rocked upward by its eccentric
portion, of the cam L, the rod m³, is raised, thereby causing. the crank,m², to

page_text: swing the valve N, forward away from the end of the air pipe n, which enters the
gas and vapor supply pipe O, at this point. The supply pipe O, conveys to the
valve chamber P, a suitable admixture of gas and air from a carburetter, mixer,
or other available source, the air pipe n, and the valve N, acting in an auxiliary
capacity. It will thus be seen that when the speed of the engine increases beyond
a prescribed degree, air will be admitted to the vapor supply pipe, to decrease the
percentage of gas supplied to the engine. The supply pipe O, opens into the valve
chamber P, in the trunk section c. Below the puppet valve p, is a chamber Q,
opening into the supply passage o, which ends in the port o'. This chamber Q,
contains the ignitor 9, which is represented as of the incandescent form, although I
do not confine myself to any special form of ignitor, since any suitable or well
known device may be employed to effect the explosion of the gases.
At the rear end of the cam shaft J, is mounted the discharge cam R, by which
the exhaust valve r, is raised at every second revolution of the power shaft H,
permitting of the escape of the products of combustion through the port s, and
discharge passage S.
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,
First. In a gas engine the combination of two power cylinders axially out of
line; a central trunk section having a chamber uniting the inner ends of said power
cylinders and formed with a gas supply passage having an induction valve and an
ignitor, and with a discharge passage containing an exhaust valve operated
intermittently and positively by a cam upon the cam shaft of the engine; trunk
pistons in said power cylinders; two piston rods connecting said trunk pistons to
rocking levers; said rocking levers; two pitmen connecting said rocking levers to
radially opposed cranks upon a common power shaft; said power shaft formed
with radially opposed cranks united by a single intermediate web; and a cam shaft
for controlling the operation of the engine, geared to and rotated by the power.
shaft, substantially in the manner and for the purpose described.
Secondly. In a gas engine the combination of two power cylinders axially out of
line; a central trunk section having a chamber uniting the inner ends of said power
cylinders and formed with a gas supply passage having an induction valve and an
ignitor, and with a discharge passage containing. an exhaust valve operated
intermittently and positively by a cam upon the cam shaft of the engine; trunk
pistons in said power cylinders; two piston rods connecting said trunk pistons to
rocking levers; said rocking levers; two pitmen connecting said rocking levers
radially opposed cranks upon a common power shaft; said power shaft formed with
radially opposed cranks united by a single intermediate web; a cam shaft for
controlling the operation of the engine, geared to and rotated by the power shaft ;
an air valve interposed in the gas supply conduit; and a governor on the cam shaft
arranged to operate said air valve, substantially in the manner and for the purpose
described.
Thirdly. In a gas engine the combination of an air valve interposed in the gas
inlet passage, mechanism for operating said air valve provided with a laterally
flexible cam lever, a laterally adjustable cam for engaging with said cam lever, and
an automatic governor for controlling the position of the said cam with relation
to the said cam lever, substantially in the manner and for the purpose described.
Dated this 11th day of December 1894
MARKS & CLERK,
18, Southampton Buildings, London, W.C., Agents.