Improvements in cr relating to Fluid-pressure Engine Valves and Valve-gear.
Year: 1898

page_text: Date of Application, 25th Mar., 1898
Complete Specification Left, 24th Jan., 1899-Accepted, 11th Mar., 1899
PROVISIONAL SPECIFICATION.
Improvements in cr relating to Fluid-pressure Engine Valves and
Valve-gear.
I, JAMES THOMPSON MARSHALL, of The Steam Plough Works, Leeds, in the
County of York, Engineer, do hereby declare the nature of this invention
to be as follows:-
:-
This invention relates to valves and valve-gear for controlling the admission
and exhaust of actuating fluid to and from the cylinders of fluid-pressure
engines.
In valve-apparatus according thereto there are two main admission-valves and
two exhaust-valves all located in parallel cylindrical chambers, which may be
provided either in the cylinder-body or, as is preferred, in the cylinder-covers.
Each main admission-valve is arc-shaped in cross-section, having two con-
centric surfaces, which communicate with each other by means of one or more
suitable longitudinal ports and, it may be, intermediate chambers formed within
the body of the valve, the outer of the said surfaces forming the valve-face and
bearing against the surface of the cylindrical chamber in which it is located.
There may be two intermediate chambers, each communicating with the valve-
face by means of one or more longitudinal ports and with the inner surface by
means of one or more longitudinal ports. The main admission-valve is provided
with projections to engage with a bridle, which is either made in one piece with,
or attached to, the oscillating valve-spindle. The main admission-valve may be
provided with a spring or springs to keep it up to its seat. In the case of high-
speed engines and high pressures it is sometimes necessary to balance the main
admission-valve, and this may be accomplished by securing to it, or forming
in one with it, a hollow extension projecting to the opposite side of the axis of
the valve and enclosing the bridle. This extension may be such as to form,
opposite to the valve, a chamber with the surface of the cylindrical chamber
containing the valve, and the springs for keeping the valve up to its seat may
then be conveniently placed in the chamber thus formed so as to act upon
the back of the extension and the surface of the cylindrical chamber respec-
tively, and may, if desired, be attached to the surface of the cylindrical chamber.
Within each main admission-valve there is placed an expansion or cut-off valve
which is also arc-shaped in cross section and has an external face that fits upon
the internal face of the main valve. One or more suitable longitudinal ports are
made through the expansion-valve, the arrangement being such that when there
are more than one main-valve port at the inner surface of the main valve all
such ports will be opened simultaneously and equally by moving the expansion-
valve. At its ends or at suitable distances apart on its inner surface, the ex-
pansion-valve has projecting from it pairs of slotted guides that receive, and
engage with, an oscillatory spindle of rectangular section, blade or other suitable

page_text: springs being provided to keep the expansion-valve against its seat.
The expan
sion-valve and main-valve shafts are mounted in suitable bearings and pass out
through suitable stuffing-boxes at opposite ends of the cylindrical chamber.
Each exhaust-valve is cylindrical and has one or more longitudinal ports formed
in it. From the axis of the valve to the periphery there is formed for its whole
length a groove or slot having parallel sides, in which engages an oscillatory
spindle of rectangular cross section, which is mounted in suitable bearings, one
being preferably in an end cover' of the corresponding cylindrical chamber, and
passes through a stuffing box at the end of the cylindrical chamber corresponding to
the projecting ends of the main admission valve spindles.
On the projecting ends of the main admission and exhaust valve spindles are
fixed arms, which may have forked or slotted ends or not and which are connected
by rods to a wrist-plate suitably mounted and provided with means whereby it
can be oscillated by the main eccentric.
On the projecting ends of the expansion valve spindles are fixed arms whose
outer ends, which may be forked or slotted or not, are connected to dies mounted
to slide in slotted curved guides, or on curved guides provided in or on a plate
suitably mounted and provided with means whereby it can be oscillated by the
expansion eccentric.
The sliding dies just mentioned are connected by rods or links to a crosshead
furnished with a block which is connected to the governor, this block moving in
guides formed either in or on the plate carrying the sliding dies.
R. E. P. CRAVEN,
Registered Patent Agent,
King Street Chambers, 52, Wellington Street, Leeds,
Agent for the Applicant.
Improvements in or relating to Fluid-pressure Engine Valves and
Valve-gear.
I, JAMES THOMPSON MARSHALL, of The Steam Plough Works, Leeds, in the
County of York, 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 relates to valves and valve gear for controlling the admission
and exhaust of actuating fluid to and from the cylinders of fluid pressure
engines.
In valve-apparatus according thereto there are two main admission-valves and
two exhaust valves all located in parallel cylindrical chambers, which may be
provided either in the cylinder-body or, as is preferred, in the cylinder-covers.
I will proceed to describe the invention by the aid of the accompanying drawings
in which
Fig. 1 is an outer side view of the main admission valve and Fig. 2 a cross
section thereof taken on line A A, Fig. 1 and showing also the expansion valve
located therein.
Fig. 3 is a partial longitudinal section of the main admission and expansion
valves, and
Fig. 4 a right hand end view thereof.
Figs. 5 and 6 are respectively a plan and end elevation of the main admission
valve separately.

page_text: Fig. 7 is a longitudinal section of part of a cylinder, showing one of the main
admission valves and port arranged in the cylinder casing, and one of the exhaust
valves arranged to control an exhaust port in the cylinder casing,
Fig. S shows a modification by a similar section of part of a cylinder with the
valve chambers arranged in the end covers.
Figs. 9, 10, and I are respectively an elevation, a plan and end view of
improved valve gear in accordance with this invention, and
Figs. 12 and 13 show two forms of a detail thereof.
Each main admission valve 1 is arc-shaped in cross section, having two con-
centric surfaces 2 and 3 which communicate with each other by means of the
longitudinal ports 4 and 5 and, in the example shown, through the intermediate
chamber 6 formed within the body of the valve, the outer surface 2 forming the
valve-face and bearing against the surface 7 of the cylindrical chamber 8 in
which it is located. In some cases there may be two intermediate chambers 6
each communicating with the valve face by means of one or more longitudinal
ports and also with the inner surface by means of one or more longitudinal
ports. The main admission valve is provided with projections 10 to engage with
a bridle 11 which is either made in one piece with or attached at one end 12
to the oscillating valve-spindle 13, the other end having secured thereto a bearing
pant 14.
In a modified form the main admission valve 1 may be oscillated from one end
only and without a bridle by forming a rectangular part 13ª on one end of the
spindle 13 which engages with a tee-shaped groove 1ª formed in one end of the
said valve see Fig. 5.
The main admission valve 1 may be provided with a spring or springs to keep..
it up to its seat.
0
In the case of high-speed engines and high pressures it is sometimes necessary
to balance the main admission-valve, and this may be accomplished by securing.
to it, or forming in one with it, a hollow extension projecting to the opposite
side of the axis of the valve and enclosing the bridle.
In the example shown the main admission valve is formed with suitable seats 15
to which is secured by means of bolts 16 the balance part 17 which bears against
the portion 18 of the cylindrical surface of the valve chamber 8. This extension
or balance part 17 may be such as to form, opposite to the valve 1 a chamber 19
with the surface 18 of the cylindrical chamber 8, the said chamber communicat-.
ing by means of an orifice 20 with the external atmosphere. The springs for
keeping the valve up to its seat may conveniently be placed in the chamber thus
formed so as to act upon the back of the extension and the surface of the cylindrical
chamber respectively, and may, if desired, be attached to the surface of the
cylindrical chamber. Or, as shown in Fig. 2, the balance part 17 may be pro-
vided at its outer face with a rectangular shaped groove 21 in which are placed
metallic packing pieces 22 kept in contact with the surface 18 by means of
springs 23 which also keep the inain valve up to its seat.
Within each main admission valve 1 there is placed an expansion or cut-off
valve 24 which is also arc-shaped in cross section and has an external face 25
that fits upon the internal face 3 of the main valve. One or more suitable longi-
tudinal ports 26 are made through the expansion valve, the arrangement being
such that when, there are more than one main valve port at the inner
surface of the main valve all such ports will be opened simultaneously
and equally by moving the expansion valve. At its ends or at suitable
distances apart on its inner surface, the expansion valve has projecting from it.
pairs of slotted guides 27 that receive, and engage with, an oscillatory spindle 28
of rectangular section or provided with rectangular parts 29, suitable springs
(not shown) being provided if required to keep the expansion valve against its
The main valve and expansion valve spindles are mounted in suitable bear-
ings and pass out through suitable stuffing boxes at opposite ends of the cylindrical
seat.

page_text: chamber, as shown in Fig. 3; one end of the expansion valve spindle 28 is mounted
in a bush 11ª carried by the bridle 11.
Each exhaust valve 30 is cylindrical and is cut away at one side to enable
the exhaust port 31 to be opened. From the axis of the valve to the periphery
there is formed for its whole length a groove or slot 32 having parallel sides 33,
33 in which slot engages a wedge shaped part 34 of an oscillatory spindle 35.
The spindle 35 is mounted in suitable bearings, one being preferably in an end
cover of the corresponding cylindrical chamber, and the other end passing through
a stuffing box at the end of the cylindrical chamber 8" corresponding to the
projecting ends of the main admission valve spindles. The main admission
valves with their expansion valves 24 and the exhaust valves 30 can be placed
in cylindrical chambers formed in the body of the cylinder as shown in Fig. 7,
or in similar chambers formed in the end covers of the cylinder as shown in
Fig. 8..
On the projecting ends of the main admission and exhaust valve spindles are
fixed arms 36 which may have forked or slotted ends or not and which are con-
nected by rods 37, indicated by dotted lines, to a wrist plate 38 suitably mounted
a short distance above the centre line of the cylinder and provided with a con-
necting rod 39 whereby it can be oscillated by the main eccentric.
On the projecting ends 28 of the expansion valve spindles 28 which passes
through a suitable stuffing box are fixed arms 40 whose outer ends are provided
with studs carrying the outer ends of the connecting rods 40° the other ends of
which are connected to dies 41 by pins 41", the said dies being mounted to slide
in slotted curved guides 42 formed in the rocking lever 43 oscillating on or with
its stud 44 carried by a bracket 45 and receiving motion from the expansion
eccentric on the crank shaft through the connecting rod 46, whose end 47 works
on the stud 48 secured to the rocking lever 43.
On the pins 41 are also placed the top ends 49 of the connecting rods 50 the
lower ends 51 of which are connected with the sliding block 52 by the pins 53.
This sliding block 52 may be guided by a slot or groove 54 formed in the lever 43
as shown in Fig. 12, or on a rectangular guide 55 formed on the said lever, as
shown in Fig. 13. The sliding block 52 is connected to a lever 56 by a connecting
rod 57, carried by the studs 58 and 59, such lever being secured on one end 60
of a rocking shaft 61, mounted in a bearing 62 on the bracket 45. The other end
of the said rocking shaft 61 has secured to it another lever 64 which is connected
to the governor lever of the engine by the connecting rod 65.
The main admission valves being operated by a wrist plate 38 mounted on a
stud placed a little above the horizontal centre line of the cylinders, such valves
are moved with the required speed to admit fluid pressure to the cylinder, whilst the
cut off valves, which are worked from the expansion gear lever, being operated
in a direct line or nearly so with the centre of such lever, cut off the admission
of fluid pressure very quickly, which in high speed engines working with high
pressures and varying loads, such as engines employed for driving dynamos,
is very advantageous and ensures very great efficiency.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed I declare that what I
claim is:-
1. In a fluid pressure engine, distributing valves comprising a main oscillatory
arc-shaped admission valve having concave and convex faces connected by suitable
ports, and an oscillatory arc-shaped expansion or cut-off valve having ports formed 5
therethrough and whose outer or convex face is adapted to oscillate upon the con-
cave face of the admission valve, the said valves being constructed, arranged and
operating substantially as hereinbefore described with reference to and shown in
Figs. 1 to 8 inclusive of the drawings annexed.
2. Distributing valves of the kind specified in the preceding claim wherein the 5
main oscillatory valve is provided with an arc-shaped balance part constructed

page_text: and arranged substantially as hereinbefore described with reference to and shown
in the drawings annexed.
3. In a fluid pressure engine, automatic expansion gear comprising a rocking
lever adapted to be oscillated by means of a moving part of the engine and pro-
vided with oppositely arranged curved slots provided with sliding dies or blocks
which are each connected to the spindle of an oscillatory expansion valve, the
said dies or blocks being also connected to a crosshead capable of being slidden in
or on the rocking lever by means of suitable links and levers connected to the
engine governor, the arrangement being such that the position of the dies or
blocks in the curved slots, and consequently the amount of cut-off, can be auto-
matically controlled substantially as herein described.
4. Expansion gear for fluid pressure engines constructed arranged and operating
as hereinbefore described with reference to and shown in Figs. 9 to 12 inclusive,
or modified according to Fig. 13 of the accompanying drawings.
Dated this 24th day of Januar 1800
R. E. P. CRAVEN,
Chartered Patent Agent,
King Street Chambers, 52, Wellington Street, Leeds,
Agent for the Applicant.