Improvements in Valve Gear.
Year: 1892

page_text: Date of Application, 9th Apr., 1892
Complete Specification Left, 9th Feb., 1893-Accepted, 8th Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear.
I, CALEB GREEN of Warnford Court, Throgmorton Street, in the City and
County of London in the County of Middlesex Commission Agent do hereby
declare the nature of this invention to be as follows:-
My invention relates to a construction of valve gear wherein lap and lead of the
valve, and the throw of the valve are effected by different forces; as, for instance,
opposite pistons or cross-heads, where two engines are employed, as in the case of.
locomotives, marine, and other duplex engines.
a
For purposes of illustration I have shown the novel combinations connected so
as to obtain the lap and lead movement from one side, and the throw from the
opposite side, and through the medium of rock shafts; but do not intend the same
as matter of limitation, for said movements may also be obtained from eccentrics
on a driving axle, or its equivalent; and, further, the novel combination which
einbraces the unit of construction may be used with a single engine. I have
therefore added to Figure 1, dotted lines which, taken in connection with the
description, will clearly indicate to anyone skilled in the art, how my invention
may be applied to single engines as well as double engines, and how the power to
move the valves may be applied by eccentrics as well as cross-heads or rock-
shafts.
The function of the valve being to regulate the alternate admission and
discharge of steam at each end of the cylinder, the valve is accordingly set so
as to be at a point beyond the middle of its travel-the required lap and lead-
when the piston is at the beginning of its stroke, and in coming to said position
the valve overcomes the lap and lead so that the admission of steam may fill the
clearance space at the beginning of the stroke of the piston.
The travel of a slide-valve operated by the ordinary link motion is slightly
greater during its passage over the middle portion of its stroke than it is at the
outer portions thereof.
In order to work effectively and economically, either with full boiler pressure or
expansively, it is desirable that the middle portion of the valve travel should be
accelerated, and the remainder of its travel correspondingly retarded, and the
longer the retarded movement can be maintained consistent with the next following
rapid movement, the better will be the results.
The objects, therefore, of my invention, is the production of a valve gear
wherein the movement of the valve shall be first accelerated during the middle
portion of its travel, to quickly overcome lap and lead and open the induction port
(the same movement having opened the exhaust port communicating with the other
end of the cylinder), and secondly, retarded or prolonged during the remainder of
the stroke, so that the full boiler pressure, or (in case of a short cut-off) the full
expansive energy of the steam, shall be obtained.
To this end the main feature of my invention embraces the combination with a
valve, of a floating lever to which the powers that give the different speeds or
rates of travel to the valve are so applied by suitable connections that said floating
lever shall be alternately a lever of the first and third order.
A second feature embraces the combination with the valve gear of a pivoted
guide box, slide, and rocker shaft, constituting a reversing mechanism whereby the
engine may be reversed with much less power than is now required.
There are other minor features of invention, all as will hereinafter more fully
appear.

page_text: I will now proceed to describe my invention more fully, so that others skilled in
the art to which it appertains may apply the same:
Figure 1. is an elevation of a valve gear embodying my invention, the full lines
indicating the connections preferred when the throw of the valve is effected by
the piston of the opposite side, and the dotted lines to the left of the drawing
indicating the preferred connections when the throw of the valves is effected by an
eccentric on the driving axle; and
Figure 2. is a plan view of the parts shown in full line Figure 1.
Like symbols refer to like parts wherever they occur.
In the drawings, which show the unit of organization, or the combination as
applicable to a single engine, and which is to be doubled for a locomotive or
double engine, A, indicates a portion of one side of the frame, and B, the cross-
head of a floating lever.
Connecting said cross-head, B, or its equivalent, with the stem, S, of the slide
valve of said side, is a floating lever, 1, which imparts to said valve its "lap and
lead "movement; and connecting said floating lever with the arm, 3, of a long
rock-shaft, 4, is a link 2, whereby the "throw of the valve on the opposite side
is effected..
5, indicates a second long rock-shaft, which extends transversely of the
locomotive frame, and at its distant end is connected with the floating lever (1) of
the opposite engine. Said long rock-shaft, 5, is provided with a crank arm, 6,
through which it is connected by a link, 7, with one arm, 8, of a short rock-
shaft, 9, journaled in the frame A, the other arm 10, of said short rock-shaft
being connected by a link, 11, with a slide, 12, adapted to move in a pivoted
guide-box, 13, the opposite end of said slide 12, being connected to the floating
lever 1, by a terminal link, 14, as indicated in dotted lines, Figure 1.
As the shaft 5 has its distant end connected with the floating lever and cross-
head of the opposite side, it will be apparent that through the medium of the
devices 5 to 14, just described, the "throw" of valve stem, S, will be effected from
the opposite side.
In case, however, it is desired to apply the power to the floating lever by means
of eccentrics, instead of rock-shafts, or to use the devices in conjunction with a
single engine, the links 2 and 7, and the long rock-shafts 4 and 5, may be omitted,
and an eccentric (5") and link (7"), as indicated in dotted lines on the left of
Figure 1, may be employed to impart the throw to the valve gear mechanism, the
floating lever, 1, receiving its lap and lead movement either from the cross-head, B,
as shown, or from a second eccentric and link connection, similar to that shown in
dotted lines.
In order to obtain a simple and efficient reversing mechanism, and one which
will distribute the friction over a large surface, and reduce the power required to
operate it, I arrange the slide 12 in a guide-box 13, pivotally supported as at 16, on
a bracket 17-17", secured to pillars a, a, projecting from the frame A. The pivot 16
should be at such a point on the line between the centre of the short rock-shaft, 9,
and the point of attachment of terminal link 14 to floating lever 1, relative to the
respective lengths of the slide bar and the terminal link, as will impart the required
travel to the lever 1 equal distances from its central position. It is important that
the point of attachment (F) of the terminal link to the floating lever should be
confined by suitable guides to move in a straight line. In the present device, this
action is secured by constructing a cross-head on the floating lever at the F point,
the ends of the cross-head having recesses, which confine it to projecting bars on
the brackets 17 and 17".
Integral with, or connected to the guide-box 13, is a pendent arm, 15, by which
the rotation of the pivoted slide box 13, may be effected, and said arm is connected
by a link with a rock-beam, R, pivoted as at 3, and thence by 'an intermediate
link to the reversing lever R'.
When, through the medium of the reversing lever and arm 15, or their equivalents,
the pivoted guide-box 13, is moved into its extreme position, either above or below;

page_text: the valve will be caused to work at full cut-off, and at intermediate positions a
graduated travel and cut-off will be obtained; while, when the slide bar is in the
plane passing through the point of attachment of link 14, to floating lever 1, and
through the centre of short rocker-shaft 9, the travel of the valve will be limited
to its lap and lead.
If the rocker arm, 10, is above the line and the slide bar is also raised, the
floating lever, 1, will be caused to move backward, and if the arm, 10, is below the
line, and the slide bar raised above the line, the floating lever, 1, will be caused to
move forward.
The operation of the valve gearing hereinbefore described will be as follows:
From the cross-head B, or equivalent source, the power which controls the lap and
lead of the valve is applied to the floating lever 1, at P; the connection of the
terminal link, 14, with the floating lever, as at F., acting for the time being as the
fulcrum, so that the lever may be said to be for the time being a lever of the first
order; next the power which controls the throw of the valve is applied to the
floating lever at the point F, and P. in turn becomes the fulcrum, and the lever one
of the third order.
But as these two powers or movements, whether the same be derived from
eccentrics (or, &c.) or from the cross-heads B-of opposite sides-do not synchronize,
their courses are at one moment in the same direction, and a moment later in
opposite directions.
When therefore, the points P. and F. of the floating lever, 1, are moving in the
same direction, the slide-valve moves less rapidly, or is retarded in its movement;
and when the points P. and F. are moving in opposite directions, the movement of
of the slide-valve is accelerated, with the results and advantages hereinbefore
pointed out.
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 a valve gear, the combination with the valve, of a floating lever and
connections for actuating the floating lever, the whole arranged so that said lever
is alternately a lever of the first and third order; substantially as and for the
purposes specified.
2. In a reversing mechanism for valve gear, the combination with the valve of a
slide, a pivoted slide-box, and a reversing lever for actuating the pivoted slide box;
substantially as and for the purposes specified.
3. In a valve gear mechanism, the combination with the valve of a floating lever
connections for actuating the same, the whole arranged so that said lever is
alternately a lever of the first and third order, a slide connected with the floating
lever, and a pivoted slide box, substantially as and for the purposes specified.
4. In a valve gear, the combination with a valve of a floating lever, 1, having one
end connected with the valve stem, and the other with the cross-head, or its equiva-
lent, and a link 14, or second power connections, between the valve stem and the first
power connection; substantially as and for the purposes specified.
5. In a valve gear, the combination with the valve of a floating lever, 1, having
one end connected with the cross-head or its equivalent, and the other with the
valve stem, a slide 12, and link 14, which connects the slide and floating lever, a
pivoted guide-box for the slide, and a rock-shaft which actuates the slide; sub-
stantially as and for the purposes specified.
6. In a valve gear, the combination with the valve of a floating lever and
connections for actuating the floating lever, the whole arranged so that said lever is
alternately a lever of the first and third order; the intermediate point of the
floating lever being controlled by suitable guides to move in a straight line, sub-
stantially as and for the purposes specified.
Dated this Eighth day of Anril 1892.

page_text: COMPLETE SPECIFICATION.
Improvements in Valve Gear.
I, CALEB GREEN of Warnford Court Throgmorton Street in the City and
County of London in the County of Middlesex, Commission Agent 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 invention relates to a construction of valve gear wherein lap and lead of the
valve, and the throw of the valve are effected by different forces; as for instance,
opposite pistons or crossheads, where two engines are employed, as in the case of
locomotives, marine, and other duplex engines.
For purposes of illustration I have shown the novel combinations connected so as
to obtain the lap and lead movement from one side, and the throw from the
opposite side, and through the medium of rock-shafts; but do not intend the same
as matter of limitation, for said movements may also be obtained from eccentrics on
a driving axle, or its equivalent; and further, the novel combination which embraces
the unit of construction may be used with a single engine. I have therefore added
to Figure 1, dotted lines which, taken in connection with the description, will
clearly indicate to any one skilled in the art, how my invention may be applied
to single engines as well as double engines, and how the power to move the valves
may be applied by eccentrics as well as cross-heads or rock shafts.
The function of the valve being to regulate the alternate admission and discharge
of steam at each end of the cylinder, the valve is accordingly set so as to be at a
point beyond the middle of its travel-the required lap and lead-when the piston
is at the beginning of its stroke, and in coming to said position the valve overcomes
the lap and lead so that the admission of steam may fill the clearance space at the
beginning of the stroke of the piston.
The travel of a slide-valve operated by the ordinary link motion is slightly
greater during its passage over the middle portion of its stroke than it is at the
outer portions thereof.
In order to work effectively and economically, either with full boiler pressure or
expansively, it is desirable that the middle portion of the valve travel should be
accelerated, and the remainder of its travel correspondingly retarded, and the longer
the retarded movement can be maintained consistent with the next following rapid
movement, the better will be the results.
The objects therefore of my invention, is the production of a valve gear wherein
the movement of the valve shall be first accelerated during the middle portion of
its travel, to quickly overcome lap and lead and open the induction port (the same
movement having opened the exhaust port communicating with the other end of the
cylinder), and secondly, retarded or prolonged during the remainder of the stroke,
so that the full boiler pressure, or (in case of a short cut-off) the full expansive
energy of the steam, shall be obtained.
To this end the main feature of my invention embraces the combination with a
valve, of a floating lever to which the powers that give the different speeds or rates
of travel, to the valve, are so applied by suitable connections that said floating lever
shall be alternately a lever of the first and third order.
A second feature embraces the combination with the valve gear of a pivoted guide
box, slide, and rocker shaft, constituting a reversing mechanism whereby the engine
may be reversed with much less power than is now required.
There are other minor features of invention, all as will hereinafter more fully
appear.
I will now proceed to describe my invention more fully, so that others skilled in
the art to which it appertains may apply the same:
Figure 1. is an elevation of a valve gear embodying my invention, the full lines
indicating the connections preferred when the throw of the valve is effected by the

page_text: piston of the opposite side, and the dotted lines to the left of the drawing indicating
the preferred connections when the throw of the valves is effected by an eccentric
on the driving axle ; and
Figure 2 is a plan view of the parts shown in full line Figure 1.
Like symbols refer to like parts wherever they occur.
In the drawings, which show the unit of organization, or the combination as
applicable to a single engine, and which is to be doubled for a locomotive or double
engine, A, indicates a portion of one side of the frame, and B, the cross-head of a
floating lever.
"
Connecting said crosshead, B, or its equivalent, with the stem, S, of the slide
valve of said side, is a floating lever, 1, which imparts to said valve its "lap and
lead movement; and connecting said floating lever with the arm, 3, of a long
rock-shaft, 4, is a link, 2, whereby the "throw" of the valve on the opposite side
is effected.
5, indicates a second long rock-shaft, which extends transversely of the locomotive
frame, and at its distant end is connected with the floating lever (1) of the opposite
engine. Said long rock-shaft, 5, is provided with a crank arm, 6, through which it
is connected by a link, 7, with one arm, 8, of a short rock-shaft, 9, journalled in the
frame A, the other arm 10, of said short rock-shaft being connected by a link, 11,
with a slide, 12, adapted to move in a pivoted guide-box, 13, the opposite end of the
said slide 12 being connected to the floating lever 1, by a terminal link, 14, as
indicated in dotted lines, Figure 1.
:
As the shaft 5 has its distant end connected with the floating lever and cross-
head of the opposite side, it will be apparent that through the medium of the
devices 5 to 14, just described, the throw of the valve stem, S, will be effected from
the opposite side.
In case, however, it is desired to apply the power to the floating lever by means
of eccentrics, instead of rock-shafts, or to use the devices in conjunction with a
single engine, the links 2 and 7, and the long rock-shafts 4 and 5, may be omitted,
and an eccentric (5") and link (7), as indicated in dotted lines on the left of
Figure 1, may be employed to impart the throw to the valve gear mechanism, the
floating lever 1, receiving its lap and lead movement either from the cross-head, or
from a second eccentric and link connection, similar to that shown in dotted lines.
In order to obtain a simple and efficient reversing mechanism, and one which will
distribute the friction over a large surface, and reduce the power required to
operate it, I arrange the slide 12 in a guide box 13, pivotally supported as at 16, on
a bracket 17-17, secured to pillars a, a, projecting from the frame A. The
pivot 16 should be at such a point on the line between the centre of the short rock-
shaft, 9, and the point of attachment of terminal link 14 to floating lever 1, relative
to the respective lengths of the slide bar and the terminal link, as will impart the
It is
required travel to the lever 1, equal distances from its central position.
important that the point of attachment (F) of the terminal link to the floating lever
should be confined by suitable guides to move in a straight line. In the present
device, this action is secured by constructing a cross-head on the floating lever at
the F point, the ends of the crosshead having recesses, which confine it to
projecting bars on the brackets 17 and 17*.
Integral with, or connected to the guide-box 13, is a pendent arm, 15, by which
the rotation of the pivoted slide box 13, may be effected, and said arm is connected
by a link with a rock-beam, R, pivoted as at 7, and thence by an intermediate
link to the reversing lever R¹.
r
When, through the medium of the reversing lever and arm 15, or their
equivalents, the pivoted guide box 13, is moved into its extreme position, either
above or below, the valve will be caused to work at full cut-off, and at intermediate
positions a graduated travel and cut-off will be obtained; while, when the slide
bar is in the plane passing through the point of attachment of link 14, to floating
lever 1, and through the centre of short rocker-shaft 9, the travel of the valve
will be limited to its lap and lead.

page_text: If the rocker arm, 10, is above the line and the slide bar is also raised, the
floating lever, 1, will be caused to move backward, and if the arm, 10, is below the
line, and the slide bar raised above the line, the floating lever, 1, will be caused to
move forward.
The operation of the valve gearing herein before described will be as follows:
From the cross-head B, or equivalent source, the power which controls the lap and
lead of the valve is applied to the floating lever 1, at P; the connection of the
terminal link, 14, with the floating lever, as at F, acting for the time being as a
fulcrum, so that the lever may be said to be for the time being a lever of the first
order next the power which controls the throw of the valve is applied to the
floating lever at the point F, and P, in turn becomes the fulcrum, and the lever
one of the third order."
But as these two powers or movements, whether the same be derived from
eccentrics (5°, &c.) or from the cross-heads-of opposite sides-do not synchronize,
their courses are at one moment in the same direction, and a moment later in
opposite directions.
When, therefore the points P, and F, of the floating lever, 1, are moving in the
same direction, the slide valve moves less rapidly, or is retarded in its movement ;
and when the points P, and F, are moving in opposite directions, the movement
of the slide-valve is accelerated, with the results and advantages hereinbefore
pointed out.
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 a valve gear, the combination with the valve, of a floating lever and
connections for actuating the floating lever, the whole arranged so that said lever
is alternately a lever of the first and third order; substantially as and for the
purposes specified.
2. In a reversing mechanism for valve gear, the combination with the valve, of a
slide, a pivoted slide-box, and a reversing lever for actuating the pivoted slide box';
substantially as and for the purposes specified.
3. In a valve gear mechanism, the combination with the valve of a floating lever,
connections for actuating the same, the whole arranged so that said lever is
alternately a lever of the first and third order, a slide connected with the floating
lever, and a pivoted slide box, substantially as and for the purposes specified.
4. In a valve gear, the combination with a valve, of a floating lever, 1, having
one end connected with the valve stem and the other with the cross-head, or its
equivalent, and a link 14, or second power connections, between the valve stem
and the first power connection; substantially as and for the purposes specified.
5. In a valve gear, the combination with the valve, of a floating lever, 1,
having one end connected with the cross-head or its equivalent, and the other with
the valve stem, a slide, 12, and link 14, which connects the slide and floating lever,
a pivoted guide box for the slide, and a rock-shaft which actuates the slide;
substantially as and for the purposes specified.
6. In a valve gear, the combination with the valve of a floating lever and con-
nections for actuating the floating lever, the whole arranged so that said lever is
alternately a lever of the first and third order; the intermediate point of the
floating lever being controlled by suitable guides to move in a straight line,
substantially as and for the purposes specified.
E. H. G. BREWSTER,
Agent for Inventor.