Improvements in or Connected with Valve Gear for Motive Power Engines.
Year: 1887

page_text: Date of Application, 13th Dec., 1887
Complete Specification Left, 11th Oct., 1888
Complete Specification Accepted, 13th Dec., 1888
PROVISIONAL SPECIFICATION.
Improvements in or Connected with Valve Gear for Motive Power
Engines.
1. DAVID JOY, of 8 Victoria Chambers in the City of Westminster, Engineer, do
hereby declare the nature of this Invention to be as follows:-
My present Invention has reference to the Invention for which Letters Patent
No. 2000 were granted to me as of the 11th day of February 1886 and has for its
object to provide means whereby the action imparted to the valve is further controlled
and made in part positive, that is to say -I employ a positive motion assisted by the
fluid pressure. In the Specification of my aforesaid Patent I describe means whereby
the movement of the valve is produced by the motive fluid admitted by a small valve
worked by gear controlled by the motion of the main valve so that the motion of the
main valve is in unison with that of the said small valve. The small valve has
however a slight precession as to time of movement gained by reduction of lap.
According to my present Invention I couple the movement of the main valve with
that of the small valve and as the two are already in unison this can be done by means
of a lever having a fixed centre and arms of a length in accordance with the lengths
of the strokes of the respective valves. (The precession of movement of the small
valve may be effected by the proportions of these arms,) and this will render the
movement of the large or main valve positive so far as the strengths of the parts of
the small valve gear allow and from this it follows that the same arrangement for
moving or assisting the moving of the valves by motive fluid may be applied to the
valves of any ordinary motive power engine wherein the valves are already moved by
machinery by attaching the valve spindle to the piston of a small assisting cylinder
which receives its motive fluid by means of a valve with a reduced motion from the
main valve gear but with reduced lap and a slight advance or lead so that the small
assisting cylinder shall take the initiative and so bear or take up the shocks of moving
and reversal of motion of the main valve. Or it may be supplied by an apparatus
such as is described in the Specification of a Patent granted to me and numbered 2668
of the year 1860 the valve being preferably controlled as to length of stroke either
4734

page_text: In this case the piston of the assisting cylinder on approaching the end of its stroke
either way passes over a hole or holes in the surface of the cylinder and allows motive
fluid to pass from the cylinder direct to either end of a small cylinder in which a piston
valve moves over ports so passing the motive fluid alternately to either end of the
assisting cylinder. The position of these holes is adjustable to control the length of
stroke of the assisting cylinder.
Or in the case of very fast running engines where also the stroke of the valve is
short the piston of the assisting cylinder may become its own valve by having suitable
ports made in it which shall pass over and uncover ports in the side of the cylinder
answering as steam and exhaust ports as described for steam hammers in the Specification
of my Letters Patent No. 283 of 1862.

page_text: COMPLETE SPECIFICATION.
Improvements in or Connected with Valve Gear for Motive Power
Engines.
I DAVID JOY of 8 Victoria Chambers in the City of Westminster, 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 present Invention has reference to improvements based mainly upon the
Invention for which Letters Patent No. 2000 were granted to me as of the 11th day
of February 1886 and more especially upon that part illustrated at Figure 4 of the
drawings accompanying the Specification of that Patent. By this Invention I am
able to provide means whereby the action imparted to the valve is further controlled
and made in part positive that is to say I employ a positive motion to assist when
necessary the fluid pressure or in other words I employ in connection with the fluid
pressure which operates the valve also a partly positive or mechanical movement as
hereinafter explained. In the Specification of my aforesaid Patent I describe means
which are illustrated in the said Figure 4 whereby the movement of the valve is
produced by motive fluid admitted by a small valve worked by gear controlled by the
motion of the main valve so that the said motion of the main valve is in unison with
that of the said small valve. The small valve has however a slight precession as to
time of movement gained by reduction of lap. In carrying out my present Invention
I couple the movement of the main valve with that of the small valve and as the two
are already in unison this can be done by means of a lever having a fixed centre and
arms of a length in accordance with the lengths of the strokes of the respective valves.
The precession of movement of the small valve may be effected by the proportions of
these arms and this will render positive the movement of the large or main valve so
far as the strengths of the parts of the small valve gear allow and from this
it follows that the same arrangement for moving or assisting the moving of the valves
by motive fluid may be applied to the valves of any ordinary motive power engine
wherein the valves are already moved by machinery by attaching the valve spindle to
the piston of a small assisting cylinder which receives its motive fluid by means of a
valve with a reduced motion from the main valve gear but with reduced lap and a
slight advance or lead so that the small assisting cylinder shall take the initiative and
so bear or take up the shocks of moving and reversal of motion of the main valve in
the manner hereinafter fully described. Or it may be supplied by an apparatus such
as is hereinafter described and shewn in Figure 3. It is analogous so far as regards
the action of the parts to that described in the Specification of a Patent granted to
me and Numbered 2668 of the year 1860 the valve being perfectly controlled as to
length of stroke either way.
In the case of very fast running engines where also the stroke of the valve is short
the piston of the assisting cylinder may become its own valve by having suitable ports
made in it which shall pass over and uncover ports in the side of the cylinder answering
as steam and exhaust ports in a manner analogous to that described for steam hammers
in the Specification of my Letters Patent No. 283 of 1862.

page_text: And in order that my said invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheets of drawings the same letters of reference indicating
corresponding parts in all the figures.
I shall refer to steam as the motive fluid but it is to be understood that I do not
limit myself to the use of steam.
In the example shown in Figure 1 1 illustrate a steam cylinder assisted by mechanical
gear. The engine is constructed generally like that described with reference to
Figure 4 of the Specification of my aforesaid Patent No. 2000 of 1886 but I couple
up the motion of the main valve F which is produced by the fluid pressure acting on
the piston F in the assisting cylinder C (and passed to the hunting lever E at the
point E¹) with the motion of the small valve D which receives that motion from the
small ordinary valve gear at E2. This coupling of the two motions takes place at or
about the neutral axis or point marked E³ of least or of no motion of the lever E
which axis may be made rigid or it may be made slightly moveable or elastic by being
fixed in a slide (as shewn) or on a spring. By the means described the two forces
controlling the main valve namely the gear worked by the engine itself and moving
the small valve and the steam admitted by the said small valve to move the main valve
are combined in the movement and therefore in case the steam should fail to move the
valve instantly or sufficiently its force is supplemented by that of the coupled valve
gear E. The respective forces may be arranged so that they are each more or less
relied upon the strength of the respective parts being adjusted accordingly.
In Figure 21 have shewn the same type of engine viz. an ordinary horizontal
engine fitted with complete valve gear which is however not necessarily of the. kind
shown but may be link or any other gear. This illustrates mechanical gear assisted
by a steam cylinder. To the valve spindle of the main valve F L attach the piston F
of the small cylinder C the valve D of the said cylinder being coupled by the links B
and levers B2 to the main valve gear through the points 662 and 63 where the motion
is suitable for obtaining the correct amount of stroke (it being already correct as to
time) to control the motion of the small valve D. In this example I have shewn an
alternative of the hunting lever E Figure 1 the said alternative consisting of a false
valve face G coupled through the lever centered at with and partaking of the
motion of the piston F¹ and so preventing its running away. In Figure 31 have
shewn the same type of engine in which attach to the valve spindle of the main
valve the piston F1 working in the small cylinder C. as before, but in this example
the valve D is moved automatically by the steam passed from the cylinder C. For
this purpose the piston of the said cylinder U is made long enough or is furnished
with prolongations ce at each end, the cylinder having recesses 3 at each end to
accommodate these prolongations, which prolongations pass over two sets of holes s. s
in the side of the cylinder and near to the end of each stroke and so allow the steam
to pass from the cylinder by the passages o. (one common to each of the set of
holes s. s to either end of the valve chest at o¹ or o² and to drive the valve D to the
end required to pass steam to the other end of the cylinder. The steam is admitted
by the steam port and passages and 2. The exhaust from either end of the
valve cylinder passes through small holes at either end of the valves into the body
of the valve which is open to the exhaust. Thus the action is entirely automatic
and the length and speed of the stroke are controlled either by checking the steam
admitted at t or by varying those of the holes s. s. in the cylinder which are open,
each set of holes s. s, for this purpose being provided with a screw plug u and by
screwing which in or out the holes can be covered and uncovered as required. In this
example also the engine is provided with ordinary or any suitable valve gear so
that the cylinder G is assistant only and relieves the ordinary gear from shock
and strain.
In Figures 4, 5 and 6 I shew three views of an arrangement for fast running
engines such as locomotive engines or the engines of torpedo boats having valve gear.
Figure 4 being a longitudinal section on the line 3. 3 Figure 5. Figure 5 being a
transverse section on the line 2. 2. Figure 4 and Figure 6, being a section on the

page_text: line 1. 1. Figure 5. The small valve D (Figures 1, 2 and 3) is dispensed with and
the piston Fi of the small assisting cylinder is made to act as its own valve-
sands are ports in the piston F the said ports passing forwards and backwards
respectively and opening out at each side of the piston as shown clearly in Figure 6.
They pass over and cover and uncover alternately the steam ports T and the exhaust
.port U formed in the side of the cylinder and thus an automatic reciprocating motion
is added to and is in unison with the motion already imparted by the existing valve
motion of the engine, and this takes up all shocks due to the momentum of the
parts and acts as a storage of force to initiate the return movements.
In Figure 7 is shown an arrangement for regulating or controlling the amount of
the cushion and intended for use in combination with the herein before described valve
gears. Thus at one end of the valve F the small piston F' is made to move in a
cylinder C which is adjustable by means of the screw c² or its equivalent whilst at the
other end the small piston F moves in a permanent cylinder (). the cushion being
adjusted as required by the valve c³ or its equivalent.
I have herein described the best ways with which I am acquainted for carrying my
Invention into effect, but I do not limit myself to the precise details of the mechanism
that should be employed as these may be varied according to the character of the
engine in which, and the purpose for which they are employed. The fluid pressure
may be of any suitable description and derived from any suitable source, for instance
it may be the steam from the boiler or steam derived from any of the valve chests of the
cylinders according to the pressure required and it may be exhausted to any other of
the valve chests at low pressure or into the condenser.
When the motive power is
derived from steam or other elastic medium it may be supplemented by adding a small
controlling cylinder containing oil water or other non-elastic medium. Or a non-
elastic medium may be used for motive power pumped to a pressure which may be
considerable in order to reduce the size of the parts so that the valves can be
worked by hydraulic power on the same principle as that on which large guns are
moved by hydraulic pressure and as the Hydraulic Machinery may be in immediate
contact with the valve chest containing steam to avoid condensation I propose to
employ the fluid at a raised temperature all the packings being of metal or heat
resisting material.
Although I have named and shewn piston valves yet my Invention may be used
with flat or D valves or any other desired form of valve.
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. In motive power engines the use of means such as are herein described for the
actuation of the valves by fluid pressure assisted at the requisite times by mechanical
valve gear or by mechanical valve gear assisted as required by fluid pressure
substantially as hereinbefore described.
2. The several arrangements and combinations of parts hereinbefore described and
illustrated severally in Figure 1 Figure 2 Figure 3 and Figures 4. 5 and 6 of the
accompanying Drawings for the purposes described.
3. In combination with the herein before mentioned valve gears the arrangement
herein before described with reference to Figure 7. of the accompanying drawings for
the purposes described.