Improvements in Reversible Valves and Eccentric Valve Gear for Steam and other Fluid Pressure Motive Power Engines.
Year: 1887

page_text: Date of Application, 14th Sept., 1887
Complete Left, 13th June, 1888
Complete Accepted, 13th July, 1888
Improvements in Reversible Valves and Eccentric Valve Gear for
Steam and other Fluid Pressure Motive Power Engines.
I, JOHN SPENCE, of Lorne House, Dunfermline, Fifeshire, Engineer, do hereby
declare the nature of my invention to be as follows:-
My Invention comprises certain improvements in valves, and reversing duplex
eccentric valve gear, specially designed for steam and other expansive fluid motive
power engines, with slide valves, or equivalent valves, for giving equal admission and
emission of the steam, or other fluid to the motive cylinders as by "Lap" and
"Lead" on the valve and a single eccentric valve rod to give a quick cut-off and
expansion at the opposite ends of the cylinders and stroke of the piston in whichever
direction the crank is turned, that is for engines which have to reverse or run in
either the forward or backward direction such as for stationary winding, hauling and
lifting engines, or for propelling locomotive and marine engines; which improvements
will enable the valves to have "Lap" and "Lead" on the inner and outer sides of
the faces, and so reverse the action of the valve and engine by admitting the steam
from the outside ends of the valve faces, and exhausting on the inside, (or vice versa
admitting the steam on the inside and exhausting from the outside when this forin of
valve is preferred); while the improved eccentric mechanism effects the said purposes
in a more simple and direct manner, and by a more simple and durable arrangement
of its parts than by other eccentric gearing heretofore used.
The nature and novelty of this new or improved duplex eccentric valve gear in
accordance with my invention consist all as follows:-In forming and fitting and
keying or otherwise securing direct on the crank shaft, the inner and smaller of the
two eccentrics, having an outer or larger ring eccentric fitted loose over it, the outer
periphery of which ring eccentric bas the eccentric straps mounted as usual on it.

page_text: with one eccentric valve rod. The inner eccentric is formed with its eccentric centre
or throw equal to half the complete throw of the valve, that is, of the width of the
port, and the lap or cover on the valve face, and as a centre to carry the outer
eccentric in the form of a loose ring; so as to turn on it to a predetermined distance,
or vice versa the central eccentric to turn within it when this distance is less than half
a turn.
Both eccentrics would have segmental stops or other equivalent to
abutt against each other at the predetermined distance they are allowed to turn loose
on each other equal to the lap and lead, and make the inner eccentric carry round
the outer eccentric ring with it, in whichever direction it is turned, to give the
reversing action of the valve for either the forward or backward rotation of the crank
and engine. The throw of this outer eccentric ring and consequently its centre and
diameter varies according to the arc distance allowed for the turning of the one
eccentric within or on the other for any given lap and lead of the valve; which arc
distance may conveniently vary as say from one half to one sixth or less of the
rotation of the ring eccentric on its axial central eccentric, or from ninety degrees to
thirty degrees, or less on either side. of the crank centre line and that of the inner
eccentric, the throw and diameter of the outer ring eccentric varying in the inverse
ratio to the length of arc; that is to say if the inner eccentric is made to turn ninety
degrees, on either side, or half a turn in all, to give the reversing action of the valve,
then the eccentricity or radius of the throw of the outer eccentric ring only requires
to be equal to the lap and lead of the valve and would give the centre line of the
outer eccentric and eccentric straps and rod on the vertical centre line of the crank.
And a simple mode of finding the throw or centre of the outer eccentric ring for
other angles of its rotation on the inner eccentric would be in supposing the crank
centre line and the centre line through the inner eccentric to coincide on the
paper, vertically through the centre of the crank shaft, then draw a circle equal to the
whole throw of the valve required that is with a radius equal to the width of the
port and the lap on the valve, and on each side of this centre line to set off parallel
lines at a width equal to the lap and lead, and through the point where these lines
cut the said circle, draw angular lines equal to the angle it is desired to turn the
eccentrics on each other. Thus for the case before stated of ninety degrees, a
straight line between these points would cut the centre line in a point giving the
radius of the circle to find the centre on the centre line from which to draw the outer
eccentric ring from, and a horizontal line through this centre point would give the
centre of the eccentric straps and rod direct to the valve. Then for sixty degrees,
forty five degrees, or thirty degrees of an oscillating arc of the outer eccentric, lines
would be drawn from the said points (cut by the parallel lines of the width of the
lap and lead on the circle equal to the traverse of the valve) equal to these 'angles
with the centre line which would give the stops on the outer eccentric, and a right
line through this would give the stops or projections on the inner eccentric,
and which would also give the point and the radius in the centre line from
which to draw and find the point or centre on it, to draw the outer eccentric ring, and
give the centre of the eccentric straps and valve rod in each case. The two eccentrics
would then act as one eccentric to give the lead and cut-off desired in whichever
direction the crank shaft and inner eccentric was turning for the time being back or
forward. For ensuring a quick reversing action of the engine, and this eccentric
gear, a friction projecting ring might be formed on the outer eccentric ring, and a
brake lever mounted on the eccentric strap to act on this until the inner eccentric in
reversing came up against the stops on the outer eccentric ring and carried it round
with it in the half or other predetermined segment of a turn allowed for this.
The outer eccentric ring may be formed in various ways to be put on and easily
fitted and secured so as to work loose on the projections and grooves of the said inner
eccentric and within the outer eccentric straps, as by making them in two halves in
the manner of the eccentric straps, and bolting them together by flanged segmental
fish plates on each side of the joint; or they may be made in two halves edgeways,
and bolted together as two complete half eccentric discs by bolts through them, in
which case they might have flanges on the outside to grasp the edge periphery of the

page_text: inner eccentric, and the outer eccentric straps working within them, or they might be
made solid or in segments with one flange on the outside to secure them in working
position and they might be formed of bush metal or have rings or segments fitted on
them at their wearing surfaces, and the abutting parts or projections may be formed
of steel, and the outer flanges of the eccentric ring might be made to form stops with
the projecting eye of the inner eccentric, or stops on the projecting eye also when that
was preferred to forming or fitting segmental stops on the working peripheries
between the two eccentrics. And in some cases as for large eccentrics, the inner
eccentric might be made in two halves and bolted together as is frequently done in
the ordinary single eccentrics.

page_text: and Eccentric valve Gear Ior
Steam and other Fluid Pressure Motive Power Engines.
I, JOHN SPENCE, of Lorne House, Dunfermline, Fifeshire, Engineer, do hereby
declare the nature of my invention, and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement in
writing reference being had to the accompanying two sheets of Drawings, and to the
letters and figures marked thereon, that is to say :-
My said Invention comprises certain improvements in valves, as hereinafter
described in reference to Figures 1 and 2, and reversing duplex eccentric valve gear,
specially designed for steam and other expansive fluid motive power engines, with slide
valves or equivalent valves for giving equal admission and emission of the acting
steam, or other fluid to the motive cylinders, as by Lap and Lead on the valve, and
a single eccentric valve rod, to give a quick cut-off and expansion at the opposite ends
of the cylinders and stroke of the piston in whichever direction the crank is turned,
that is for engines which have to reverse or run in either the forward or backward
direction, such as for stationary, winding, hauling and lifting engines, or for propeling
locomotive and marine engines; which improvements will enable the valves to have
Lap" and "Lead on the inner and outer sides of the faces, and so reverse the
action of the valve and engine by admitting the steam from the outside ends of the
valve faces and the valve casing, and exhausting through the inside of the valve faces
and valve, (or vice versa admitting the steam on the inside and exhausting from the
outside,) when this form of valve is preferred; while the improved eccentric mechanism
effects the said purposes in a more simple and direct manner, and by a more simple
and durable arrangement of its parts than by other eccentric gearing heretofore
used, and while suitable for this class of valve is also suitable for other forms of D or
slide valves.
<<
And in order that my said invention and the manner of performing or carrying the
same into effect or practice may be properly understood, I have hereunto appended
two explanatory Sheets of Drawings, in which the same reference letters are used to
indicate corresponding parts in all the Figures where shown. Figure 1 on Sheet 1
shows a sectional elevation of a modification of the new or improved valve slide A, and
its steam casing B, on its working face D' of the cylinder D, a short central part of 3
which only is shown, to indicate the ports d, d, of the inner and outer ends of the
cylinder respectively, with the central port d2, between them, which may either be an
exhaust port or a steam port, as determined by the reversing steam valve of the engine.
This valve A, is formed with a valve face A2 on its upper side (the same as that A, on
the lower side) working on a steam face plate E, with hollow steam chamber within 8
a gland ring E³, turned and fitted steam-tight with angled spring or split stuffing-box
rings E, between it and a disc E", all fitted steam tight within a faucet chamber B
on the casing cover B', fitted with a tightening pinching screw and jam nut B² outside,
for tightening up the said chamber face plate E, E¹, upon the back face A² of the

page_text: valve A. The valve A, has the ports a, a', in its two faces A', A', communicating by a
chamber through it, the port a' communicating with the chamber E, E¹, through the
port e in its face plate E, so as to equalize the pressure on both faces A1, A2, of the
valve, whether the cylinder D gets its steam through the inner chamber a of the valve A
and port or exhausts through these. The valve faces A', A', over the ports d, d, are
formed with lap, over these ports, both on their outer ends, and on their inner ends next
the port a in the valve. In Figure 1 is also shown a side or end view of one con-
struction of the new duplex reversing eccentric G, H, for actuating the valve A; the
straps S, of which are connected with the end of the eccentric valve rod A+, shown
as broken away from the joint valve rod A³ at the stuffing box B³, of the casing B.
But with the eccentrics and valve all set for the crank F₁, and eccentrics turning
in the forward direction, as indicated by the arrows, and the cylinder D, obtaining
the steam from the valve casing B, past the outer ends of its valve face A¹, A', and
exhausting through the central port a and passage & also indicated by the arrows.
While Figure 2, on Sheet 1, shows corresponding views of the same valve A, casing B,
and cylinder D, and reversing eccentrics G, H, as set for the engine turning backwards
or in the reverse direction to that shown in Figure 1, and as receiving the steam from
the central passage and port and inside a of the valve A, and exhausting direct
from the ports d, d', past the end faces A', A¹, of the valve A, into the casing B as
indicated by the arrows in this Figure, and all as will hereinafter be more particularly
described. The casing B, and the passage d communicate with a duplex or double
passage pipe and reversing valve, such as that described in the specification of my
patent No. 6407 May 12 1886, suitable for giving steam either to the outside or inside
of the valve A. Figure 3 shows an edge section of the eccentrics G, H, on the irregular
line 1-1 in Figure 1, and Figure 3 A is a corresponding edge section showing a different
mode of putting the eccentrics together.
Figure 4 on Sheet 2 shows a sectional side or end view of a modification of the new
reversing eccentrics G, H, as more suitable for large engines, the inner or main
eccentric G, secured to the crank shaft E, being made in two parts at C, and secured
by screw and cotter pins at C. Figure 5 is a sectional plan corresponding to Figure 4;
while Figure 6 is an end section. Figures 7 to 10 are various diagram views, ior
showing the mode of constructing the double reversing eccentrics G, H, and finding their
respective centres.
Referring to the Figures on Sheet 1 and Figure 7 on Sheet 2 of these Drawings,
the nature and novelty of this new or improved reversing duplex eccentric valve gear,
in accordance with my invention, consist all as follows:-In forming and fitting and
keying or otherwise securing direct on the crank shaft F, the inner and smallest G,
of the two eccentrics G, H, having the outer or larger ring eccentric H, fitted to turn
oscillate loose over it to a predetermined extent of 90° the outer periphery of which
ring eccentric H, has the usual eccentric straps S, S, mounted on it with one jointed
eccentric valve rod A³ A+. The inner fixed eccentric G may be formed with its
eccentric centre g, and "throw" o,g, equal to half the complete throw of the valve or
more or less, that is, to the width of the port d or d¹ and the lap or cover on the
valve face A¹ over it at either end, as a centre to carry the outer eccentric H in the
form of a loose ring; so as to turn on it to a predetermined distance, or vice versa
the central eccentric G, to turn within it. Both eccentrics G and H, have segmental
or other equivalent stops, gl,g, and h¹, h, as shown in Figures 1, 2, and 7, to abutt
against each other at the predetermined distance they are allowed to turn loose on each
other, equal to, or so as to give the lap and lead. The eye g', of the inner eccentric G, is
here made to form the stop on two hollow ares at h', formed on the side flanges H, H",
of the outer ring eccentric H, instead of the segmental stops h", shown in Figures 4 & 7,
so as to make the inner eccentric G, carry round the outer eccentric ring H, with it,
in whichever direction it is turned, to give the reversing action of the valve A, for
either the forward or backward rotation of the crank F, and engine, as hereinbefore
described in reference to Figures 1 and 2 and indicated by the arrows in these
Figures. The crank F' on the crank shaft F, in these Figures is shown in dotted

page_text: *
lines on the inner dead centre, as respectively turning in the upward and downward
directions, with the steam entering accordingly from the outer, and the inner
edges of the valve face A¹, to the port d, leading to the outer end of the cylinder D,
and exhausting through the port d, from the inner end of the cylinder D, through the
inside of the valve A, to the port and passage d², and to the casing B, respectively, for
turning the engine and crank F¹, in the forward and backward directions, of these
Figures. The throw" of this outer eccentric ring H, and consequently its centre, h,
and diameter varies according to the predetermined are distance allowed for the turning
of the one eccentric within or on the other, suitable for any given lap and lead of the
valve. This are motion or distance, may conveniently vary, say from one-half to one
sixth of the circle or rotation of the ring H, on the eccentric G, or from ninety degrees
to thirty degrees, on either side of the crank centre line or that Of of the inner
eccentric G, at right angles to the crank centre line O, F, the "throw and diameter
of the outer ring eccentric H, varying in an inverse ratio to the length of are; that is
to say, if the inner eccentric G, is made to turn ninety degrees, on either side, or half
a turn in all, to give the reversing action of the valve, then the eccentricity or radius
of the throw of the outer eccentric ring H, only requires to be equal to the lap and
lead of the valve A, and would give the centre line of the outer eccentric H, and
eccentric straps S and rod A' on the vertical centre line of, to that OF, of the
crank Fas shown for a half revolution of 18 degrees in the Diagram Figure 8.
As
A simple geometrical mode of finding the "throw," or centres of the inner and
outer eccentrics G and H, for other assumed angles of rotation of the one eccentric
within or on the other, is shown on the large diagrams Figures 7 to 10. The first
Figure 7 is taken for 45 degrees of an angle on each side of the right line Of, or
90 degrees of a turn of the eccentric H on G being that assumed for the eccentrics
G and H, shown in Figures 1 to 3, Sheet 1. But the other diagrams Figures 8 to 10
respectively show the mode of finding the centres for a rotation of 180 degrees, 120
and 60 degrees respectively of the outer eccentric EI, on the inner eccentric G.
shown in these diagram views Figures 7 to 10 O is taken as the centre of the crank
shaft F, and 0 F2, the crank centre line, and the centre line through the inner
eccentric G is shown at Of, at right angles upwards or vertically through the centre O
of the crank shaft and fixed eccentric G. To find the centre of the eccentrics G and H,
Figure 7, draw the circle 11, from the centre O, equal to the whole throw of the
valve required, that is with a radius OI, equal to the width of the port d or d', and
the lap on the valve; and on each side of the centre line Of, set off parallel lines i,
to it, at a width equal to the lap and lead and through the points i, where these
lines ii, cut the said circle I, draw lines ij, at an angle, equal to the angle it is
desired to turn the eccentrics G and H on each other, on either side of, the said centre
line Othrough the crank shaft, namely 45 degrees in this case, or 90 degrees in
all, cutting each other at g, where it gives the centre of the inner eccentric G. Thus
for the case before stated of 90 degrees in all, the straight line between these points g
and i, gives the radius of the are i to find the centre on the centre line ✪ from
which to draw the outer periphery of the eccentric ring H, and a horizontal line
through this centre point would give the centre of the eccentric straps S and
rod A³, A', direct to the valve A, as seen in Figure 7 and in Figures 1 and 2. Then
for angles of 60 degrees and 30 degrees, with oscillating arcs of the outer eccentric H
of 120° and 60° respectively, as shown in Figures 9 and 10, lines would be drawn
from the said points i, i, (cut by the parallel lines i i¹, of the width of the lap and
lead on the circle I, I, equal to the traverse of the valve) equal to these angles with
the centre line of which would give the stops " on the outer eccentric H, and a
right line through the centre g, would give the stops or projections g" on the inner
eccentric Gas shown in Figure 7, and which would also give the radius gi, in the
centre line Of, from which to draw and find the point or centre on it, to draw the
outer eccentric ring H, and give the centre of the eccentric straps S, and valve
rods A³, A', in each case. The two eccentrics G, H, would then act as one eccentric
to give the lead and cut-off desired in whichever direction the crank shaft and inner

page_text: eccentric G was turning for the time being back or forward, as shown and described
in reference to Figures 1 and 2, by the action of the abutting surfaces h¹ and g¹ or "
and in Figure 7.
The outer eccentric ring H, may be formed in various ways to be put on and easily
fitted and secured so as to work loose on the projections or grooved circumference of
the said inner eccentric G and within the outer eccentric straps S, as by making them
in two halves disc or ring-wise with a joint El' in the centre within the straps, with
flanges H on their outer edges to keep the straps S in working position, as seen
in Figures 1, 2, and 3, and also grasp and work over the edge periphery G² of the
inner eccentric G, and have the stops working within the space gas indicated in
Figures 4 and 7 and also bolted together by screw holts and nuts h³, as shown in
Figures 1, 2, and 3 on Sheet 1.. Or the outer eccentric H might be made solid or in
segments as an eccentric ring with solid flanges H³ on the one outside, and a loose
ring on the other side, or segments at H³, screwed on the opposite side to secure this
outer eccentric H in working position on the inner eccentric G, and within the
eccentric straps S, as indicated in Figure 3A; and they might be formed of bush
metal or of steel, or have rings or segments of bush metal or steel fitted on them at
their working and wearing surfaces, and the abutting parts or projections 11 may be
formed of malleable iron or steel, screwed on at ", as seen in Figure 4. Or other-
wise the outer flanges H", of the eccentric ring H might be made to form are
stops, with the projecting eye g' of the inner eccentric G, as shown in Figures 1 and 2,
or other stops might be formed on the projecting eye gl also when that was preferred
to forming or fitting segmental stops shown in Figures 4 and 7, on the working
peripheries between the two eccentrics G and H. And in some cases, as for large
eccentrics, the inner eccentric G might be made in two halves checked and bolted
together by screw pins and cotters or nuts as indicated at C, C', in Figures 5, 6, and 7
on Sheet 2, and as is frequently done in the ordinary single eccentrics. And the
eccentric ring H may be made in two halves as half eccentric rings checked at its
end joints e in the same manner as the inner eccentric G and screwed together by
bolts c' and segmental fish plates c* sunk or checked into the segmental rings Hat
the joint e, as also shown particularly in Figures 4 and 6.
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 :-
First. The construction, or general arrangement and combination of the parts of
slide valves, and reversing duplex eccentric valve gear, for steam and other fluid
pressure motive power engines for giving the acting steam or fluid either from the
outside end faces of the valve, or from the inside and reversing the engines and giving
cut-off and expanson at both ends of the cylinder all substantially as, and in the
manner herein described, in reference to and shown in the accompanying Drawings.
Second. In steam and other fluid pressure motive power engines the construction of
a reversing slide valve with "lap" and "lead" on its inner face and ports, as well as
on its outer faces, for giving the steam from the inside of the valve as well as from
the outside for reversing the, engine, all substantially as herein described in reference
to and shown in the accompanying Drawings.
Third. In steam and other fluid pressure motive power engines, the operating of
the slide valves by duplex eccentric valve gear to give "lap" and "lead" on the
inner and outer sides of the valve faces, and so reverse the action of the valve and
engine, by admitting the steam from the outside ends of the valve faces and casing,
and exhausting through the inside; or vice versa, admitting the steam from the inside
and exhausting from the outside, substantially as and in the manner herein described, in
reference to and shown in the accompanying Drawings.
Fourth. In steam and other fluid pressure motive power engines, the construction
and use of a duplex eccentric for operating the steam distributing slide valves, con-
sisting of inner and outer eccentrics, the inner one G being formed with its eccentric

page_text: ::
centre as a centre to carry the outer eccentric H in the form of a loose ring, so
that the one eccentric may turn on the other a predetermined distance to give the
lap" and "lead" of the valve in advance of the crank in whichever direction it is
turning, substantially as, and in the manner herein described, in reference to and
shown in the accompanying Drawings.
Fifth. In steam and other fluid pressure motive power engines, the forming of the
duplex eccentrics G and H with segmental stops g, h, or making the eye g¹ of the
inner eccentric to form the stops ' on the segmental circles on the outer ring eccentric H,
so that the inner eccentric Gabutts against the outer eccentric H and carries it with
it to the predetermined distance they are permitted to turn loose on each other, to
give the "lap" and "lead," substantially as and in the manner herein described in
reference to and shown in the accompanying Drawings.
1000