Improvements in Valve Operating and Governing Mechanism of Gas and Oil Motor Engines.
Year: 1892

page_text: Date of Application, 30th May, 1892
Complete Specification Left. 28th Feb., 1893-Accepted, 15th Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in Valve Operating and Governing Mechanism of
Gas and Oil Motor Engines.
I, JOHN HENRY HAMILTON of Sandiacre in the County of Derby Engineer
do hereby declare the nature of this invention to be as follows:-
My present improvements are most usefully applied to engines of small size and
I proceed to describe their application to gas engines working on the well known
four stroke cycle. In such engines I fit a rotating valve which controls
the admission of gas and air and the exhaust of the products of combustion.
This valve is preferably arranged at the back end of the cylinder with
its axis parallel to that of the crankshaft and on one of the ends of the valve
which projects through the bearing in which the latter works I arrange a
series of ratchet teeth the number of such teeth being a multiple of the number
of revolutions corresponding to a cycle, that is to say in the engine I am
now describing the number would be even and 1 prefer to use four teeth. To
operate this ratchet wheel I arrange a pawl on a vibrating arm centred in the
rotary valve and connected to the end of the crank pin of the engine or to an
eccentric on the crankshaft by means of a coupling rod the relative positions of
the parts being so arranged that the valve shall have a slight lead relatively to the
piston that is to say the vibrating arm which operates the valve shall commence its
forward stroke before the crank has turned the back centre.
During this forward stroke corresponding in the main to the forward stroke of
the piston the pawl engages with one of the ratchet teeth and moves the valve,
while during the return stroke which corresponds in the main to the back stroke of
the piston the valve remains at rest.
I shall now describe the way in which the valve effects the distribution of gas,
air and exhaust and the method of governing.
In the casing carrying the valve and forming a bearing for it I arrange a port
leading to the cylinder an exhaust port an air port and a gas port and in the
valve itself two recesses which serve to put the port leading to the cylinder into
communication with the exhaust and admission (gas and air) ports alternately.
When the piston arrives near the end of the explosion stroke the valve puts the
port leading to the cylinder into communication with the exhaust port and the
valve remains in this position during the next backward stroke of the piston. At
the commencement of the next forward stroke the valve beginning its movement
first closes the exhaust port and immediately thereafter opens the gas and air
ports these ports remaining open till near the end of the stroke when they are closed
and the piston on its next back stroke compresses the charge. I have supposed in
the above that the engine is working full power and taking in gas and air during
each alternate forward stroke but for governing the speed when working at less
than full power I cause the valve to remain in the exhausting position during one
or more revolutions after the exhaust stroke has been made and this is effected by
so disposing the weight of the pawl that when the speed is too great the combined
inertia and centrifugal force of its parts balance the tension of the spring (which
tends to bring the pawl into an engagement with a tooth) and this engagement
does not take place and the valve remains at rest till the speed has sufficiently
falleu. To ensure that this non-engagement shall only take place while the
exhaust port is open and not at the beginning of the explosion stroke I cause the
ratchet teeth corresponding to the latter stroke to project more than the others so
that the spring being more extended shall exert a greater force to bring the pawl

page_text: into engagement. Or I may give more clearance between the end of the pawl and
the face of the ratchet teeth corresponding to the explosion stroke than between it
and the other teeth and thus not only allow more time for the spring to return the
pawl but also cause the engagement to take place when the inertia is less than it
is at the very beginning of the stroke and thus ensure the preponderance of the
spring.
Or I may combine both methods for ensuring the engagement at the proper
time.
In engines of larger size I may use the ordinary mushroom valves for admission
and exhaust and in that case I would substitute for the rotary valve a rotary cam
or cams which would effect the distribution by opening or closing the mushroom
valves.
A timing valve may be operated by the rotary cam or by the vibrating arm.
In applying my improvements to oil engines I propose to substitute for the gas
port a hole leading from a small oil pump which pump may be operated by the
revolving valve; and passages or grooves in the latter may serve to control the
admission to and discharge from the pump.
Dated this ooth .. of M 1000
JOHN H. HAMILTON.
COMPLETE SPECIFICATION.
Improvements in Valve Operating and Governing Mechanism of
Gas and Oil Motor Engines.
I, JOHN HENRY HAMILTON, Engine Works, Sandiacre, in the County of Derby,
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 relates to improvements in valve operating and governing
mechanism of gas and oil motor engines my improvements being particularly
adapted to engines of a small size working on the principle of the well known four
stroke cycle.
In carrying out my invention with an engine of this character I employ a
rotating valve which controls the admission of gas and air and the exhaust of the
products of combustion. This valve is preferably arranged at the back end of the
cylinder with its axis parallel to that of the crank shaft, and on one of the ends of
the valve which projects through the bearing in which the latter works I arrange
a series of ratchet teeth the number of such teeth being a multiple of the number
of revolutions corresponding to a cycle that is to say in the engine I am now
describing the number would be even and I prefer to use four teeth.
To operate this ratchet wheel I arrange a pawl on a vibrating arm centered in
the rotary valve and connected to the end of the crank pin of the engine or to an
eccentric on the crank shaft by means of a coupling rod the relative positions of
the parts being so arranged that the valve shall have a slight lead relatively to the
piston that is to say the vibrating arm which operates the valve shall commence its
forward stroke before the crank has turned the back centre.
During this forward stroke of the valve corresponding in the main to the
forward stroke of the piston the pawl engages with one of the ratchet teeth and
moves the valve, while during the return stroke which corresponds in the main to
the back stroke of the piston the valve remains at rest. Thus the commencement
of one of the valve strokes causes the exhaust to close and the gas and air ports to
open while the end of that stroke causes the valve to close the gas and air ports.
The next outward stroke commences by giving more lap or cover at the port
leading to the cylinder and ends by fully opening the exhaust port both back
strokes of the piston taking place while the valve is at rest. Means are also
provided for causing the valve to remain at rest with the exhaust port open and

page_text: ensuring that it shall remain in this position only, for two or more consecutive back
strokes so as to control the speed.
To clearly explain my invention reference is made to the accompanying drawings
in which :-
Figure 1 is a side elevation of a four stroke cycle gas engine with my improve-
ments applied thereto.
Figure 2 is a plan of same.
Figures 3 and 4 are sections on an enlarged scale through the rotating valve and
casing or seat showing the valve in different positions.
Figures 5 and 6 are end views of the valve showing the parts in different
positions.
Figure 7 is a longitudinal section of the valve casing or seat on line a―x of
Figure 4 the valve being removed.
Figure 8 is a longitudinal section of the valve on line x-x Figure 4 without
the valve casing or seat.
Figure 9 is a side elevation of an engine showing a modification of my invention
by which mushroom lift valves may be operated.
Figures 10 and 11 represent different shaped cams on the crank shaft for giving
motion to the valve or valves.
Referring first to Figures 1 to 8:-The valve casing consists partly of a
projection 1, cast with the cylinder cover 2, and partly of a cover 3, the valve
opening or seat being bored in each of same so that when the cover 3 is removed
the valve can be reached for inspection or otherwise. The cover 3 is held to the
part 1 by adjusting springs 4 (Figures 1 and 2) while spaces 5. 5 which may be
filled with asbestos or the like may be left between the cover and part 1, for the
purpose of taking up wear &c. The valve which is hereafter described is mounted
on a spindle which is journalled in a central opening 6 of same said spindle being
attached to an arm 7, said arm having a pawl 8 pivoted to it at 9 and being
operated by means of the rod 10 from the crank pin or as shown from an extension 11
of same.
The rod 10 is so set in an inclined position as to cause the valve to have a
certain amount of lead relatively to the piston.
The valve which is normally a cylindrical body as shewn in Figs. 3, 4 and 8 but
has certain portions cut away for passages, has attached to it or integral therewith
a disc 12 in which are inserted and secured four hardened steel teeth 13, 13, 14, 14,
so that each half revolution of the valve corresponds to a complete cycle with an
engine as described of the four stroke type. In the body of the valve are cut away
two recesses 15, 15, Figs. 3, 4 and 8 which have smaller side extensions 16, 16,
while the end portion opposite to the disc 12 is formed with or consists of a dise or
head 17 to assist in keeping the valve in its seat longitudinally. The recesses 15, 15
and 16, 16 serve to bring the port 18 leading to the cylinder into communication
alternately with the air and gas ports which are marked 19 and 20 respectively and
with the exhaust port 21.
The valve is shewn in Fig. 3 in the position in which it is left by the pawl at the
end of the explosion stroke the exhaust being full open during nearly the whole of
the next back stroke. In Figure 4 the valve is shewn in the position in which the
pawl leaves it at the end of the suction stroke.
To govern the speed of the engine I form the pawl with a mass or weight 22 on
the end of same, the inertia of which tends to throw the pawl away from a stop
block 23 fixed on the back of the arm 7 when the arm 7 is fully back, but this is
opposed by a spring 24 the centrifugal force of the mass 22 and its weight; the
effect of all these forces combined being to cause the pawl to miss engagement with
tooth 13 Fig. 5 when the engine is running too fast, and thus leave the valve
in the position shewn in Fig. 3 while the engine makes 1, 2, 3, 4, 5 &c. revolutions
according to the load upon it.
To ensure that the pawl shall ouly miss the teeth 13, 13, and shall always engage
the teeth 14, 14, that is, that an explosion shall always be followed by the opening

page_text: of the exhaust I make the teeth 14, 14 project further than 13, 13 as shewn
in Figs. 5 and 6 and thus the spring 24 being more extended as the pawl passes the
point of the tooth 14 than it is when passing the point of the tooth 13 exerts a
greater force to bring the pawl into engagement.
I prefer also to pitch the teeth unequally so that not only shall the teeth 14
project more but also that there shall be more clearance at their points or noses 25
and thus the forces tending to bring the pawl into engagement shall have a longer
time to act and as the inertia of the mass 22 will also be less and the centrifugal
force greater as it moves forward from its extreme position the engagement of the
pawl with the tooth 14 will be certain to take place.
The cycle of operations in the engine itself helps to secure the engagement at the
right time because the speed will always be higher on the stroke following an
explosion than on the third stroke after the explosion stroke.
The speed may be varied by controlling the action of the mass 22 which is
effected by hooking the spring 24 on to the different notches in the pin 26 said pin
being attached to the block 23.
The space 27 in the casting 1 shown at Figs. 3 and 4 is in communication with
the water circulation and serves to keep the parts cool.
The complete cycle or action of the engine is as follows:-When the piston
arrives near the end of the explosion stroke the valve puts the port 18 leading to
the cylinder into communication with the exhaust port 21 and the valve remains in
this position during the next backward stroke of the piston.
At the commencement of the next forward stroke the valve beginning its move-
ment first closes the exhaust port 21 and immediately thereafter opens the air and
gas ports 19, 20, these ports remaining open till near the end of the stroke when
they are closed and the piston on its next back stroke compresses the charge.
I have supposed in the above that the engine is working full power and taking in
gas and air during each alternate forward stroke but for governing the speed when
working at less than full power I cause the valve to remain in the exhausting
position during one or more revolutions after the exhaust stroke has been made.
This is effected by so disposing the mass 22 that the resulting moment of the
inertia, the centrifugal force and the weight of same, balances or overbalances that
of the tension of the spring which tends to bring the pawl into engagement with a
tooth, such balancing action causing an engagement to fail to take place and the
valve to remain at rest till the speed has sufficiently fallen. To ensure that this
non-engagement shall only take place while the exhaust port is open and not at the
beginning of the explosion stroke I cause the ratchet teeth corresponding to the
latter stroke to project more than the others as previously described so that the
spring being more extended shall exert a greater force to bring the pawl into engage-
ment. Or I may give more clearance between the end of the pawl and the face of the
ratchet teeth corresponding to the explosion stroke than between it and the other
teeth and thus not only allow more time for the spring to return the pawl but also
cause the engagement to take place when the inertia is less than it is at the very
beginning of the stroke and thus ensure the preponderance of the spring. Or I may
combine both methods for covering the engagement at the proper time.
Though I have described my improvements as applied to the 4 stroke type of
engines they may be applied to the 6 stroke type in which case the number of teeth
on the ratchet wheel would be 3 or 6 and the recesses in the valve would be
different and the tooth or teeth on the ratchet corresponding to the charging stroke
only, would be formed so that the pawl would fail to engage with it or them when
the speed is too great. The rod 10 may also be operated from a suitable cam on
the main or crank shaft, such cam being formed or timed to give the requisite
movement to the rod 10.
In applying my improvements to oil engines, I propose to substitute for the gas
port a hole leading from a small oil pump which pump may be operated by the
revolving valve; while passages or grooves in the latter may serve to control the
admission to and discharge from the pump.

page_text: When lift valves of the mushroom type are used they may be operated as shewn
in Fig. 9. In this the revolving disc 12 takes the place of the revolving valve and
operates through cams one of which is indicated at 29" and the pivoted cranked
arms 29, 29, the charge admission valve 30 and the exhaust valve 31 the admission
valve 30 controlling the air ports 32, 32 and the gas ports 33, 33. The disc or
cam 12 may also operate a timing valve if such is used. An eccentric 34 on the
crank shaft serves to give motion to the rod 10 and is set in advance of the
crank.
It is obvious that instead of an eccentric a cam as 35 Fig. 10. may be used to
operate the vibrating arm 36 and rod 10 and it may have two equal projections as
shewn in which case the cam 12 would make a revolution every cycle or it may be
so shaped that the disc or cam 12 will make one revolution in two cycles such shape
being shewn in Fig. 11.
In this case the vibrating arm 36 would make part of its forward stroke when the
crank is near the back centre and the remainder of this stroke when the crank is
near the forward centre.
It is evident that the construction shewn in Figs. 1 to 8 might be combined with
that shewn in Fig. 9 as for instance by making the revolving disc or cam 12 a
valve to admit the charge and having a cam attached to or formed in a piece with
it to operate the exhaust but I consider the construction shewn is best.
Or the disc or cam 12 may be itself a valve of the disc type having ports in its
flat face, such disc being operated by the improved means above described.
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:-
1. In gas or oil engines, an intermittently rotated cylindrical valve, having
passages for controlling the admission of the charge and the exhaust, a seat or
casing for same having corresponding passages, teeth secured to the valve, a pawl
for engaging with said teeth, and a connection between the pawl and the crank shaft
for operating said pawl, substantially as described.
2. For operating a rotating distributing valve in gas or oil engines of the four
stroke type, the mechanism consisting of an extension of the crank pin, a coupling
rod, an oscillating arm carrying a weighted and spring controlled pawl and a series
of ratchet teeth attached to the valve the whole being arranged and operating
substantially as described with reference to Figs. 1 to 6 of the accompanying
drawings.
.
3. In gas or oil engines provided with mushroom valves the mechanism for
operating the same comprising cams attached to or fixedly connected with a
ratchet wheel, a weighted pawl adapted to engage with the teeth and an oscillating
arm connected with an eccentric or cam on the crank shaft substantially as
described.
4. In gas or oil engines provided with a mushroom exhaust valve the combination
of an intermittently rotating cylindrical admission valve operated by means of a
pawl and ratchet wheel and a cam attached to said admission valve the cam being
adapted to operate the mushroom exhaust valve substantially as described.
5. In oil engines of the four stroke type the combination of a rotating valve
operated by means of a pawl and ratchet motion having passages for the admission
of the charge and exhaust; and an oil pump operated by means of a cam attached
to or forming part of the rotating valve substantially as described.
6. For controlling the speed of gas or oil engines having an intermittently
rotating valve, an intermittently rotating cam operating a valve or valves a pawl
weighted at its outer extremity and a series of ratchet teeth attached to the
rotating valve or cam whereof the teeth engaged with the pawl during the explosion"
stroke have a greater radial projection than the others substantially as and for the
purpose described.
7. For controlling the speed of gas or oil engines having an intermittently

page_text: rotating valve, an intermittently rotating cam operating a valve or valves, a pawl
weighted at its outer extremity and a series of ratchet teeth attached to the rotating
valve or cam whereof those teeth engaged with the pawl during the explosion stroke
are nearer to those in advance of them than to those which follow, substantially as
and for the purpose described.
8. In gas or oil engines having an intermittently rotating valve or cam the con-
structions whereby ratchet teeth either unequally pitched or having unequal radial
projection or both arc secured to or formed on the rotating valve or cam substan-
tially as described.
9. In gas or oil engines the several arrangements and combinations of parts
described with reference to the accompanying drawings.
Dated the 28th day of February 1893.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Chartered Patent Agent.