Improvements in Explosion Engines.
Year: 1897

page_text: Improvements in Explosion Engines.
We, WALTER FIRMAN, of Ferndale, Higham Road, Engineer, and Aмos CAVE,
of the Firm of John Cave & Sons, of High Street, Manufacturers, both in
Rushden, in the County of Northampton, do hereby declare the nature of this
invention to be as follows:-
This invention relates to explosion engines of the kind wherein two pistons are
arranged in a common cylinder and in connection with a common crank shaft,
the object of the invention being to simplify the construction and increase the
efficiency of such engines.
According to the said invention we employ one cam for operating the gas
valve, the inlet valve for the explosive mixture and the exhaust valve, means
being employed for moving one or a part of one of the connecting media between
the cam and the valves out of the path of the cam when another or part of
another connecting medium is being operated.
In a suitable arrangement for carrying out our invention we make a groove in
the cam disc engaging with projections on friction rollers rolling against the cam
surface, the said rollers being adapted to slide upon pins at the one end of levers
the other ends of which are arranged in connection with the valves, which are
closed by springs suitably arranged in connection therewith.
For governing the supply of gas to the engine, the gas valve is adapted to be
operated from one of the levers herein before described through the medium of a
weighted arm or pendulum so that while the engine is running at a normal speed
the said arm is adapted to open the valve, but when running faster than the
normal speed the arm not moving as quickly as the lever, misses the valve which
therefore does not open to supply the gas.
We find it advantageous to employ ball and socket joints for the joints between
the crank connecting rods and the oscillating levers through the medium of
which the pistons are connected to the cranks and also for the joints of the con-
necting rods connecting the said pistons to the said oscillating levers, the latter
arrangement of joints allowing the pistons to rotate in the cylinder and thus
equalize the wear of both, the cylinder also lasting a longer time before a liner is
required than heretofore.

page_text: Rushden, in the County of Northampton, 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 explosion engines of the kind wherein two pistons are
arranged in a common cylinder and in connection with a common crank shaft,
the object of the invention being to simplify the construction and increase the
efficiency of such engines.
According to the said invention we employ one cam for operating the gas
valve, the inlet valve for the explosive mixture and the exhaust valve, and to
permit of this we provide for moving one or a part of one of the connecting
media between the cam and the valves out of the path of an operating projection
on the said cam when another or part of another connecting medium is being
operated by the said projection. In a suitable arrangement for this purpose we
make a groove in the cam disc engaging with projections in connection with anti-
friction rollers rolling against the cam surface, the said rollers and projections
being adapted to slide upon pins at one end of levers the other ends of which
are arranged in connection with the valves.
Springs are provided for moving the levers in the reverse direction to that in
which they are moved by the operating projection on the cam, for the purpose
of closing the valves.
The gas valve for governing the supply of gas to the engine receives its motion
through the medium of one of the levers herein before described and of a
weighted arm or pendulum pivoted to the said lever and a push piece upon the
said pendulum which is designed to impinge against the stem of the gas valve.
To enable our invention to be fully understood we will describe the same by
reference to the accompanying drawings, in which:-
Figure 1 is a side elevation partly in section of an engine having our improve-
ments applied thereto; and,
Figure 2 is a sectional end elevation of the same.
Figure 3 is a sectional plan shewing the arrangement of the cam and the
adjacent ends of the valve levers.
Figure 4 is a sectional elevation illustrating the arrangement of the parts
through the medium of which the gas valve is operated;
Figures 5, 6, 7 and 8 are diagrammatic views illustrating the operation of the
cam.
a is the cylinder of the engine which cylinder as shewn is composed of three
sections the end sections of which are provided with feet b, b so that the said
cylinder practically forms the bed plate of the engine whilst the central section
is provided with the brackets c, c in which the crank shaft d is mounted.
e,e are the pistons working in the cylinder the motion of which is communi-
cated to the crank-shaft d through the medium of the rods f,f, the beams or
levers g, g and the crank connecting-rods h, h. As shewn in the drawings the
piston connecting rods f,f are connected with the pistons e, e and with the
oscillating levers g, g by ball and socket joints, as this arrangement of joints
allows of the pistons turning more or less in the cylinder upon their axes, thus
equalizing the wear over the whole surface of the pistons and at the same time
over the surface of the cylinder whereby the latter will work longer before a
liner is required than heretofore. We also find it advantageous to joint the con-
necting rods h, h to the levers g,g by ball and socket joints in the same manner.
The crank pins to which the rods h, h are connected are arranged between crank-
discs h¹ in a manner which will be clearly understood by reference to Figure 2.
i is the valve for the admission of the explosive mixture into the cylinder
and is the exhaust valve the said valves as shewn being of the mushroom type
and having their stems projecting through casings.
* is the cam for operating the valves i, j and k¹ the projection or rib thereon.

page_text: 1, m are the levers through the medium of which the motion of the cam is com-
municated to the valves i, j respectively, m' being the anti-friction rollers
which are mounted upon the said levers and against which the cam projection k
directly acts. The shafts upon which the said rollers ', m³ rotate are made of
much greater length than the width of the rollers. so as to permit of the said
rollers being in position to be acted upon by the projection of the cam or to
be out of the path of the said projection, the ends of the levers carrying the said
pins being fork-shaped or bifurcated, as clearly shewn in Figure 1.
fitted
n is the groove in the cam disc k for moving the said rollers in the required
manner and o, pare plates having projections o¹, upon them, respectively,
which enter the grooven, the said plates being respectively
into circumferential channels in the rollers , m' and at their rear end sliding
upon bars, carried in the upper ends of the levers 1, m parallel with the
shafts upon which the anti-friction rollers slide, as will be clearly understood by
reference to Figure 3.
r, sare springs which serve to maintain the rollers 1, m¹ in contact with
the face of the cam k. is the gas valve which is arranged upon one side of the
casing of the valve and operated from the lever in one direction and on the
other by a spring t¹. u is an arm projecting from the boss of the lever and v
is the weighted pendulum which is suspended upon the said arm, as clearly shewn
in Figure 4, the said pendulum being provided with the push piece w which when
the pendulum is in its normal position relatively with the said arm u, as shewn
in Figure 4, is designed, as the arm swings in the direction of the arrow in the
said figure, to impinge against the stem of the gas valve and to push the same
inwards to allow the admission of gas into the casing of the valve i where it
mingles with the air. c is a spring attached at one end to the pendulum and
at the other end to a horn y upon the arm u, the said spring being in tension and
serving to normally retain the pin z upon the pendulum weight in contact with
the arm u.
With this arrangement while the engine is running at a normal speed the
push piece will at each oscillation of the arm u impinge against the stem of the
valve t; should, however, the engine run above its normal speed so that a sudden
movement is imparted to the arm u each time that the projection of the cam
acts against the lever 1, then the pendulum, owing to the inertia of the weight
upon it, would practically remain at rest notwithstanding the movement of the
arm u, the spring permitting of this relative movement of the pendulum r and
the said arm u; as the pendulum therefore does not move it will be obvious that
as the arm moves forward the push piece not having been moved with the
pendulum will miss the stem of the valve t so that the latter will not be opened.
z is a pin which limits the movement of the arm u relatively with the pen-
dulum when the latter remains stationary owing to the force of inertia.
The operation of the engine herein before described is as follows:-
Assume the pistons to be in their innermost positions and the inclined ends of
the projection upon the cam k to be adjacent to the rollers 1, m' as indicated
in Figure 1 and also in the diagram Figure 5; as now the crank shaft with the
cam k rotates in the direction of the arrow Figure 5 the projection k¹, will, during
the first half revolution and outstroke of the pistons act upon the roller to move
the lever to operate the valve i and the gas valve t, the pistons as they separate
drawing in a charge of gas and air whilst at the same time the groove n of the
said cam will act upon the projection in connection with the roller m' and
move it out of the path of the projection k¹ so that at the completion of the first
half revolution the rollers l, m₁ occupy the positions shewn in Figure 6. During
the second half revolution of the cam, when the pistons are moving inwards to
compress the explosive charge drawn in during the previous outstroke, the roller /¹
will be acted upon by the cam groove n and moved towards the centre of the
cam so that the two rollers l', m¹ then occupy the relative positions shewn in

page_text: Figure 7 both being out of the path of the projection . During the next or
third half revolution when the pistons move outwards under the force of an
explosion the roller m' is moved outwards to the position shewn in Figure 8 so
that during the next or fourth half revolution, when the pistons are moving
inwards to expel the products of combustion the cam projection kl will act upon
the roller m' to open the exhaust valvej to allow these products of combustion to
escape. During this last half revolution the roller is moved back to the
position shewn in Figure 5 ready to be operated by the projection ¹ to open the
valve as herein before described.
It is to be understood that the engine may be run in either direction by
properly arranging the cam k relatively with the pistons and crank shaft for
instance if without altering the positions of the rollers l', m² relatively with the
axis of the crank shaft the cam is turned half round that is to say from the
position shewn in Figure 5 to that shewn in Figure 6, the engine will run in a
reverse direction to that in which it runs when the parts are in the relative
position shewn in Figure 5.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. In an explosion engine the employment of a single cam for controlling the
operation of the valves for admitting the constituents of the explosive charge
and of the exhaust valve, substantially as described.
2. In an explosion engine the arrangement of a single cam for controlling the
operation of the inlet and exhaust valves the said cam being provided with a
projection which operates upon levers for opening the valves and with a cam
groove which also operates upon the said levers to move the ends against which
the projection acts out of the path of the said projection during the time that
the valves are to remain closed, substantially as described.
3. In engines of the kind herein before described connecting the pistons with
their rods by ball and socket joints, substantially as described.
4. In an explosion engine the arrangement in connection with the lever
through the medium of which the gas valve is operated, of a pendulum carrying
a projection which acts against the gas valve to open it, which pendulum at a
normal speed is held rigid relatively with the lever by a spring the said spring
when the lever is moved above the normal speed being adapted to yield to allow
a relative movement between the pendulum and the lever, substantially as
described.
5. The manufacture and use of the improved gas engine constructed and
arranged substantially in the manner herein before described and illustrated in
the accompanying drawings.
Doted the 4th dor of Inne 1998
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.