Improvements in Gas Motor Engines.
Year: 1892

page_text: Date of Application, 3rd Mar., 1892
Complete Specification Left, 3rd Dec., 1892-Accepted, 7th Jan., 1893
PROVISIONAL SPECIFICATION.
Improvements in Gas 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:-
The first part of this invention relates to an improved arrangement of gas and
admission valves specially applicable to the type of engine described in Specification
No. 16434 though also applicable to other types of engine. In that Specification
an admission valve with an annular gas valve surrounding its stem was described
and my present improvement consists in an arrangement whereby both valves are
operated by one spindle and push piece.
For this purpose I make the gas valve a loose sliding fit on the admission valve
spindle and fix a collar on the latter below the former in such a position that the
admission valve has a certain amount of free lift before the gas valve shall be
opened and I form two notches or steps in the end of the admission valve spindle so
that when the push piece enters the outermost of these the admission valve shall
be lifted through a greater distance than the clearance between the collar and the
gas valve and the latter will also be lifted but when the push piece enters the other
notch the admission valve will be raised through a less distance and the gas valve
will not be opened.
The push piece above mentioned is provided with a steel blade and is pivotted to
the lever which operates the admission and exhaust valves being held against a
stop in. the lever by a spring so as to engage with the outermost notch except
when the governor displaces it laterally and causes it to engage with the other
notch.
When intended for use with Dowson or other weak gas, I may attach to or form
on the gas valve a ring adapted to partially cover the air inlet ports when the gas
valve is raised so as to partially block the air passage when the gas valve is
opened.
The governor may be of any ordinary type but I prefer the following arrange-
ment which constitutes the second part of my invention.
To a fixed part of the engine I pivot a lever or bell crank and place a weight on
the arm or one of its arms such arm being preferably horizontal and to the same
lever or bell crank I pivot a tumbler piece with two slots or notches in it one of
these being adapted to engage with a pin fixed in the lever which operates the
valves and the other with a pin in the push piece the former pin resting in the
bottom of its notch when the lever is full back or farthest away from the admission
valve spindle and the latter pin striking the bottom of its notch when the lever
and push piece are advancing towards the valve spindle the tumbler being so
arranged that when the pin in the push piece comes in contact with the bottom of
its notch the weight on the lever or bell crank shall be descending.
If the speed of the engine be too great the violence of the impact will overcome
the pull of the spring which keeps the push piece against the stop and the push
piece will be thrown to one side so that it will engage with the innermost notch
and so the gas valve will not be opened.
I may arrange that should the speed from any cause such as the sticking of the
gas valve become excessive the push piece shall be thrown so much to one side that
it shall not engage with either of the notches and so the admission valve would not
be opened at all provided that its spring is strong enough.
The speed of the engine may be varied by moving the weight along the arm of
the lever or bell crank.
The above arrangement of gas and admission valves may also be applied to

page_text: engines of the type described in my Specification No. 601500 but in this case I
prefer to adopt a different form of governor consisting also of a lever with an
adjustable weight but in this case connected to the push piece by means of a short
link whereof one end is jointed to the lever and the other to the push piece in such
a way that the lever which carries the push piece (and operates the valves) forms
wih the short link a toggle joint and at the beginning of its stroke gives the
governor lever carrying the weight a sharp movement but afterwards a diminishing
motion as the joint approaches to and passes the line of centres.
The third part of my invention relates to an improved igniting device for
facilitating starting and for timing the ignitions after the engine started and is
suitable for use with hot tube ignition. For this purpose I propose to use a separate
block of metal into which is screwed the ignition tube and to which is attached the
chimney. In this block is drilled a hole communicating with the interior of the
combustion chamber and the other end of this hole is closed by a timing valve
opening outwards. From the chamber containing this valve two lateral passages
are formed one leading to the ignition tube and the other to a chamber which has
an outlet to the atmosphere closed by another valve opening inwardly. These
valves may both be operated from one lever and may be connected to it by screws
geared together. The action is as follows.
The Bunsen burner being lit, the tube brought to a red heat, the engine turned
past the back centre on the explosion stroke and the screws properly adjusted the
lever is pressed in till the timing valve nearly rests on its seat and the other or
inwardly opening valve is nearly full open the lever held in this position by a
catch and a jet lit outside the external orifice of the ignition chamber. A charge
of gas is then introduced either by forcing it in by means of a pump or by letting
the pressure of the gas force it into the combustion chamber till it burns outside
the external orifice of the igniting device. The catch may now be released thus
shutting in the flame in the igniting chamber and fully opening the timing valve
leading to the combustion chamber and igniting the charge therein.
When the engine has been properly started by means of this ignition the screws
may be so adjusted that the inwardly opening valve shall not be opened at all and
the other valve will then act simply as a timing valve opening a connection between
the combustion chamber and the ignition tube at the right time.
The lever may be operated by means of a cam and roller in the usual manner.
Dated this 2nd day of March 1892.
JOHN H. HAMILTON.
COMPLETE SPECIFICATION.
Improvements in Gas Motor Engines.
I, JOHN HENRY HAMILTON of 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 partitularly described and ascertained in and by the
following statement :—
The first part of this invention relates to an improved arrangement of gas and
admission valves specially applicable to the type of engine described in Specification
No. 1643489 though applicable also to other types. In that Specification an
admission valve with an annular gas valve surrounding its spindle was described
and my present improvement consists in an arrangement whereby both valves are
operated by one spindle and push piece.
I now proceed to describe this part of my invention with reference to the accom-
panying drawings of which
Fig. 1 represents a section through the admission valve casing of such an engine
as is described in Specification No. 164348.
The gas valve 1 is made a loose sliding fit on the admission valve spindle 2 and
covers a ring of holes or annular passage leading from the gas passage 3.

page_text: On the admission valve spindle 2 1 fix a collar 4 allowing a certain amount of
clearance between this collar and the bottom of the gas valve 1. The ports 5 serve
to admit air below the admission valve.
At the lower end of the admission valve spindle are two notches 11 and 12
formed preferably by cutting away the spindle as shewn and fitting a hardened
steel plate 6 into the slot. This plate projects on each side of the spindle and passes
through slots in the boss 8 which forms a guide for the spindle and thus prevents
the latter from turning. The spring 9 bearing against the projecting ends keeps
the admission valve on its seat.
This construction is also shewn at Figs. 3 and 4 which show my improvement
applied to a horizontal valve similar to that described in Specification 601500.
A push piece 10 Figs. 1 and 2 pivotted to the operating lever 7 is arranged so
that it can engage with the notch 11 in which case the valve and spindle will be
raised enough to bring the collar in contact with the gas valve and open the latter
or with the notch 12 in which case the valve will not be raised sufficiently to bring
the collar in contact with the gas valve and the latter will remain shut.
The action of the governor will determine whether the push piece shall engage
with the notch 11 or 12 and this governor may be of the centrifugal type or of that
known as the pêndulum or inertia type but I prefer to use the one shewn in Figs. 1
and 2 which I term an impact governor which constitutes the second part of my
invention and which I now proceed to describe.
The push piece is pivotted on the pin 13 secured to the valve operating lever 7
and has a downward extension in which is fixed the pin 14. A tumbler 15 has slots
formed in it in which the pins 13 and 14 work and is pivotted on the pin 16 secured
to the governor lever 17 which is carried by the pin 18 fixed in a non-moving part
of the engine.
The governor lever 17 carries a weight 19 which may be moved along the lever
to vary the speed.
The action of the apparatus is as follows:-
When the valve operating lever 7 rises after being pushed down to its lowest
position by the cam 20 it will bring the parts into the position shewn in Fig. 2 in
which both of the pins are in contact with the ends of the slots in the tumbler.
Immediately before arriving in this position the pin 13 only was in contact and as
it is above the line joining the fulcrum of the valve operating lever 7 to the centre
of the pin 16 the weight 19 will be descending. Immediately after the parts arrive
in the position shewn in Fig. 2 the pin 14 only is in contact and the weight 19 is
rising. The result is that the pin 14 strikes the end of the slot and by its impact
instantaneously reverses the direction of motion of the lever 17 and weight 19. If
the pressure on the pin 14 due to this is sufficiently great the push piece will be
thrown to the right and will enter the notch 12 while if it is less it will not
overcome the pull of the spring 21 and the push piece will engage with the
notch 11.
The speed may be lowered by moving the weight 19 towards the end of the
governor lever 17 and may be increased by moving it towards the tumbler 15.
It is obvious that the above described governor is equally applicable to the
ordinary arrangement of valve gear, wherein a separately operated gas valve is
operated by a hit and miss device.
In engines driven by fuel gas or other weak gas of which a large volume
relatively to that of the air is required it is usually necessary to throttle the air
passages and increase the size of the gas passages which results in a loss of power
when the governor cuts out an ignition because the whole cylinder full of air has to
be drawn in through the contracted passages.
I obviate this defect by forming on the gas valve 1 a ring 22 Fig. 3 between
which and the gas valve proper a sufficiently large passage is allowed for the
increased volume of gas. The air admission ports 5 are so placed that this ring
partially blocks their inner ends when the gas valve is raised but leaves a free

page_text: passage when an ignition is cut out by the action of the governor as above
described.
In my Provisional Specification 1 described a form of governor specially
applicable for use with a horizontal valve of the form described in my Specification
No. 60150 but I have found it less sensitive than that hereinbefore described with
reference to Figs. 1 and 2. and I prefer in this case also to use the latter type which
it is obvious can be equally well adapted to a horizontal valve by altering the
position of the parts and making the lever 17 straight or nearly so instead of bent
as shewn.
I also described in my Provisional Specification a method of starting gas
engines but have found it is liable to fail in action and I therefore do not further
describe it here.
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. An admission valve having two notches near the outer end of its spindle and
a collar secured to the latter and adapted to come in contact with the gas valve
when the push piece which operates the valve engages with the outermost notch,
but not to come in contact with the gas valve when the push piece engages with the
innermost notch substantially as described with reference to Figs. 1, 2, 3 and 4.
2. The use of the ring 22 forming part of or attached to the gas valve substan-
tially as and for the purposes described.
3. The special construction consisting of a plate. 6 passing through slots in the
admission valve spindle and in the guide therefor and having notches in which the
spring nests, substantially as described.
4. In governing arrangements of the hit and miss type the use of a tumbler such
as 15 pivotted to a weighted lever 17 and having slots in which two pins work one
of the said pins being secured to the valve operating lever and the other to the push
piece which operates the gas valve substantially as described.
Dated this 2nd day of December 1892..
JOHN HENRY HAMILTON.