Improvements in Valve Gear for Gas and other Engines.
Year: 1891

page_text: Date of Application, 9th Dec., 1891
Complete Specification Left, 21st Dec., 1891-Accepted, 23rd Jan.,
1892
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear for Gas and other Engines.
1, JAMES JOHN MILLER, of 35 Dorville Road, Hammersmith, in the County of
London, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention has reference to improved means for operating exhaust valves of
gas and other engines having a multiple stroke cycle, the object being to simplify
and cheapen the construction of such engines.
In one arrangement, suitable for an engine having a four stroke cycle, the exhaust
valve is operated by a cam fixed on the crank shaft of the engine and formed with
a cylindrical extension around which and the cam proper extends an endless groove
into which takes a pin or one end of a lever (hereinafter included in the expression
pin) connected to or arranged to work in connection with the exhaust valve. The
arrangement is such that during three successive half revolutions of the crank
shaft the exhaust valve will remain at rest but during the fourth half revolution
or the greater part thereof the exhaust valve will be held open by the action of the
cam upon the pin.
The pin, which is kept in engagement with the cam groove by a spring or its
equivalent, may be arranged to move laterally in relation to the cam and its
cylindrical extension in order that it may accommodate itself to the cam groove;
or the cam and extension may be caused to move endways on the crank shaft with
a like object.
For an engine working with a six stroke cycle the cam groove may be made
to extend twice around the cylindrical extension of the cam so that the exhaust
valve will be open only during each successive sixth half revolution of the crank
shaft.
In a modified arrangement, a cam groove forming a double turn is made in one
side of a disc or plate fixed on the crank shaft, a suitable switch being provided to
cause the pin, at the required times, to enter that portion of the groove designed
to actuate the exhaust valve. Suitable means such as a disc arranged parallel
to the cam plate may be employed to keep the pin in engagement with the cam
groove.
In another arrangement the cam is in the form of a ring or collar formed with
an annular groove to receive the valve operating pin, and provided with a cam-
piece movable endways and arranged to be actuated by suitably arranged tappets
in the direction of the axis of the shaft and across the annular groove, the arrange-
ment being such that during three or other desired number of successive half
revolutions of shaft the cam piece will occupy a position in which it will be
inoperative upon the piu, but during the fourth or other desired half revolution
of the shaft will extend across the groove so as to operate the pin and open
the valve.
The exhaust valve instead of being actuated directly by the cam may be actuated
by a rod having a strap encircling a slotted disc mounted to turn with the crank
shaft and the centre of motion of which can be varied by a cam plate of the kind
hereinabove described.
In a modified arrangement the valve actuating rod with strap is arranged to
encircle a sphere mounted to turn with the crank shaft. This sphere is formed
with a tapering slot through which the crank shaft passes and has connected to it
an arm arranged to be actuated by a cam plate of the kind hereinabove referred
to, the arrangement being such that at each fourth or other desired half revolution
of the crank shaft, the sphere will be moved into a position in which it will be

page_text: eccentric to the axis of the crank shaft thereby operating the rod and opening the
exhaust valve.
Dated this 9th day of December 1891.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Valve Gear for Gas and other Engines.
I, JAMES JOHN MILLER, of 35 Dorville Road, Hammersmith, in the County of
London, 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:
-
This invention has reference to improved means for operating exhaust valves
of gas and other engines, for example hydrocarbon motors, having a multiple
stroke cycle, the object being to simplify and cheapen the construction of such
engines.
In one arrangement, suitable for an engine having a four stroke cycle, the exhaust
valve is operated by a cam fixed on the crank shaft of the engine and formed with
a cylindrical extension around which and the cam proper, extends an endless groove
into which takes a pin or one end of a rod or lever connected to or arranged to
work in connection with the exhaust valve. The arrangement is such that during
three successive half revolutions of the crank shaft the exhaust valve will remain
at rest, but during the fourth half revolution, or the greater part thereof, the
exhaust valve will be held open by the action of the cam upon the pin, rod
or lever.
In the accompanying drawings,
Figs. 1 and 2 are elevations at right angles to each other, and both partly in
section, of a vertical gas engine working with a four stroke cycle and the exhaust
valve of which is opened by a cam of the kind just referred to.
Fig. 3 is an under side view of the cam and its extension when in the position
shown in Figs. 1 and 2.
1 is the motor cylinder carried by uprights 2 and having its trunk piston 3
connected by a rod 4 to the crank shaft 5 in the ordinary manner. 6 is the exhaust
pipe in which is the exhaust valve 7 that is to be held open during each fourth
stroke, or the greater part thereof. 7" is the stem of the valve. 8 is the cam fixed
on the crank shaft and having a cylindrical extension 9 around which and the cam
proper, extends the endless groove 10 the two parts of which cross at the point 11.
In this groove works the lower end 12ª of a valve rod 12, which end is made of
the elongated form shown in Fig. 3 so as to readily pass across the junction 11 of
the two portions of the endless groove. The upper end of the valve rod terminates
in a socket 12b in which the valve stem 7ª rests. The valve rod, in the arrange-
ment shown, works through slotted guides at 13, 13 and 13b that permit it to
move laterally in relation to the cam and its cylindrical extension in order that its
lower end may readily pass, during the rotation of the crank shaft, from that
portion of the endless groove that extends around the cam, to that which extends
around the cylindrical extension and vice versa.
Or the cam with its extension, may, with a like object be caused to rotate with
the crank shaft by a feather, and to move endways thereon to the desired extent,
at the required times. For this purpose the cylindrical extension may be made
longer and be formed with a separate endless groove 10* as shewn in Fig. 34 into
which extends a fixed pin 12. In this case the endless groove 10 shewn in
Figs. 1, 2 and 3 can be dispensed with, the lower elongated end of the valve
rod then working on the plain peripheries of the cam 8 and its extension 9
alternately.

page_text: 14 is a spring arranged to bear at one end against the guide 13 and at the other
end against a collar 14 on the valve rod so as to keep the lower end of the valve
rod in the endless groove.
With the construction described it will be seen that during three successive
strokes of the engine, and whilst the lower end of the valve rod is in the portion of
the endless groove that extends around the cylindrical extension and around that
part abc of the cam that is concentric with the crank shaft, the valve rod will not
be raised, but that during the next stroke and whilst the lower end of the valve rod
is in the portion of the groove corresponding to the part cda of the cam, the
exhaust valve will be held open.
For an engine working with a six stroke cycle the groove 10 may be made to
extend twice around the cylindrical extension of the cam as shewn in dotted lines
in Fig. 3, so that the exhaust valve will then be open only during each successive
sixth half revolution of the crank shaft.
In the modified arrangement shown in Figs. 4 and 5, which are elevations at
right angles to each other, a cam groove 10, 10% forming a double turu is made in
one side of a disc or plate 3* fixed on the crank shaft 5, a suitable switch 15, which
is pivoted to the disc or plate, being provided to cause, at the required times, the
elongated pin 12" to pass from the inner annular portion 10 of the groove, to the
outer portion 10" thereof which is designed to actuate the exhaust valve. With
this arrangement it will be seen that the pin 12 after passing from the end a of
the outer portion 10° of the groove, will pass completely around the inner annular
portion 10 and in so doing will act against the tail 15 of the switch and partly
turn the switch on its pivot so as to bring its nose 15 across the inner annular
portion of the groove, so that the pin after again moving in the portion of this
groove between a and the switch, will be guided into the outer portion 10%. Thus
during three successive strokes of the piston, and whilst the pin is travelling in the
inner portion 10 of the groove, the valve rod will be at rest, with the exhaust valve
closed, but during the next stroke, and whilst the pin is travelling through
the outer portion 10" of the groove, the valve rod will be held in a raised position
with the exhaust valve open. The pin upon entering the said outer portion of the
groove, again acts against the switch, but so as to move its nose out of the inner
portion of the groove, and its tail into that groove so that during the next one and
a half revolutions, or thereabout, of the crank shaft, the pin will travel in the inner
annular portion of the groove as before.
Suitable means, such as a disc 16 mounted on the crank shaft parallel to the cam
disc or plate 8*, may be employed to keep the pin 12" in engagement with the cam
groove.
In another arrangement, shewn in cross section and side elevation respectively in
Figs. 6 and 7, there is employed a ring or collar 17 formed with an annular
groove 18 to receive the lower end of the valve rod 12, and provided with a cam
piece 19 arranged to slide in a slot cut in the collar in the direction of the axis of
the shaft 5 and across the annular groove. This cam piece is arranged to be
actuated by a collar 17ª formed with an endless groove 17b that extends twice
around the collar and into which extends a fixed pin 17. By this arrangement it
will be seen that during each alternate rotation of the crank shaft the cam piece
will be in a position in which it will not extend across the groove 18, whilst during
the other alternate rotations it will extend across such groove with the result that
during three half revolutions the cam piece will be inoperative upon the valve rod,
but during the next or fourth half revolution it will operate the rod and open the
valve.
The exhaust valve instead of being actuated directly by the cam shewn in
Figs. 4 and 5 may be indirectly actuated thereby as shewn in end and side
elevations respectively in Figs. 8 and 9. In this arrangement the valve rod 12
terminates at its lower end in a strap 12' that encircles a slotted disc 21 mounted
to turn, by means of the squared block 22, with the crank shaft, and provided with
a pin 23 that extends into a cam groove of the kind shewn in Fig. 4, and formed in

page_text: he disc 8*. By this means the centre of motion of the slotted disc will be made
eccentric to the axis of the crank shaft when the pin 23 passes into the outer
portion of the cam groove, so that the disc at this time will occupy a position in
which it will hold the valve rod in a raised position with the exhaust valve open.
In the modified arrangement shewn in Figs. 10 and 11, the valve actuating
rod 12 with strap 12 is arranged to encircle a sphere 24 pivoted at 25 to the crank
shaft 5 so as to turn therewith. This sphere is formed with a tapering slot 26
through which the crank shaft passes, and by means of which it is free to partly
turn about its pivot 25. To it is connected one end of an arm 26 the other end of
which is arranged to enter a cam groove of the form shewn in Fig. 4, formed in
the cam plate 8* fixed on the crank shaft, the arrangement being such that at each
fourth or other desired half revolution of the crank shaft, the sphere will be moved
by the action of the outer portion of the cam groove into the position shewn in
dotted lines, in which it is eccentric to the axis of the crank shaft, thereby lifting
the valve rod and opening the exhaust valve.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Valve gear for gas and other engines working with a multiple stroke cycle,
wherein the exhaust valve is opened during the fourth or other desired stroke of
the engine by a cam fixed on the crank shaft of the engine and formed with a
cylindrical extension around which and the cam proper extends an endless groove
into which takes a pin or one end of a rod or lever connected to or arranged to
work in connection with the exhaust valve substantially as hereinbefore described
with reference to and shewn in Figs. 1, 2 and 3 of the drawings annexed.
2. The modified construction of valve gear shewn in and described with reference
to Fig. 34.
3. Valve gear for gas and other engines working with a multiple stroke cycle
wherein the exhaust valve is opened during the fourth or other desired stroke of
the engine by a cam disc or plate fixed on the crank shaft, formed with a cam
groove 10, 10 and provided with a switch such as 15 arranged and operating sub-
stantially in the manner herein before described, whether such cam disc or plate be
arranged to actuate the valve rod directly as in Figs. 4 and 5 or indirectly through
a plate or sphere capable of being moved by the cam disc or plate into a position
eccentric to the crank shaft as in Figs. 8 and 9 and in Figs. 10 and 11 respectively
of the drawings annexed.
4. Valve gear for engines of the kind herein referred to constructed arranged
and operating substantially as hereinbefore described with reference to Figs.
and 7 of the drawings annexed.
01
D
1001
W. Lloyd. Wise,
JAS. J. MILLER.
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.