Improvements in or in connection with Corliss Valves of Steam Engines.
Year: 1896

page_text: Date of Application, 12th Mar., 1896
Complete Specification Left, 12th Dec., 1896-Accepted, 27th Feb., 1847
PROVISIONAL SPECIFICATION.
Improvements in or in connection with Corliss Valves of Steam
Engines.
I, WILLIAM PORTER of Moanarone, Bandon, Ireland, do hereby declare the
nature of this invention to be as follows:-
This invention relates to Corliss valves and has for its object more especially a
trip gear for such valves of steam engines regulated by a governor.
In carrying my invention into effect, I proceed as follows:-
An eccentric on the crank shaft or some other piece which moves in accordance
with the engine, gives endlong motion to a bar that slides in fixed guides parallel
to the piston rod, but does not rotate. Two latches are pivoted or attached by
springs to this bar in such wise that they are free to move in a plane perpendicular
to the valve spindles. They are pressed towards these spindles by suitable springs
which may be the pivoting springs themselves or others. The free end of each
latch carries a ratchet tooth projecting towards the valve spindles, the faces of
these two teeth are turned in opposite directions, and are involute or nearly so in
form. When a tooth is advancing, its face engages at a certain point of its travel
with a projection on an armi carried by the valve spindle, and thus opens the valve
more and more until the circular motion of the projection carries it clear of the
face of the tooth. A spring attached to the valve then closes it as usual. When
the motion of the sliding bar is reversed, the inclined back of the ratchet tooth
meets the projection on the valve spindle held fast against the stop, and is simply
depressed against the action of the springs until the tooth has been carried clear of
the projection.
The size of the are of opening of the valve depends on the depth to which the
ratchet tooth is engaged with the stud. The springs attached to the latches tend
to increase the depth of this engagement, but two roller-protected studs playing on
inclined straight or curved surfaces on the latches regulate the distance to which
this engagement can take place. The roller-protected studs are carried by two
symmetrically placed levers pivoted on fixed points, whose free ends are connected
with the thrust-rod of the governor by links, racks or other means, so that as the
speed of the engine rises, the thrust-rod moves the levers and presses the studs
against the guiding surfaces on the latches, thus reducing the depth of engagement
of the ratchet teeth, and at the same time reducing the arc of opening of the valves
and the steam supply. I lay special stress on the separation of the ratchet tooth
and valve rod arm projection by the straight line motion of the one and the circular
motion of the other, the extent of this notion which is necessary for release of the
valve being regulated by the governor.
,
1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in or in connection with Corliss Valves of Steam
Engines.
I, WILLIAM PORTER of Moanarone, Bandon, Ireland, 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 of steam engines of the kind commonly known
as Corliss valves, and has for its object more especially, a trip gear so arranged
that an acceleration of speed of the engine works a diminution of steam inducted
and conversely, thus obtaining a greater uniformity of speed.
The invention will be understood from the following description, reference being
had to the accompanying drawings, in which,
Figure 1 is a general view in front elevation of my improved gear;
Figure 2 an end view thereof;
Figure 3 shows an arrangement for connecting thrust rod of governor with the
controlling levers, by the use of straight and curved racks as an alternative to the
slotted lever ends and sliding pin;
Figure 4 an end view thereof.
Referring to these figures, A A' are the spindles of the steam valves which
rotate within their bored cylindrical seats, B a rod or bar that slides parallel
with the piston rod in fixed guides C, but does not rotate. This bar is operated by
an eccentric on the crank shaft, or some other piece which moves in accordance
with, or is operated by, the engine and gives a longitudinal motion to the bar B.
D D' are two latches or levers, which are pivotted to this bar B at E E¹ and are
each provided with inclines d for the purpose hereafter set forth. The free ends
of the levers D are supported by springs F in such wise, that while they are
reciprocated longitudinally by the motion of the bar B, yet they are free to move
perpendicularly on their axes by virtue of the resiliency of the springs F. These
springs which reciprocate longitudinally with the levers press the rods D towards
the spindles A A', and normally keep them in line with the bar B. The free ends
of the levers D.D' carry ratchet teeth G G projecting towards the valve
spindles A A'. The faces of these two teeth operate in opposite directions, and
may be involute or nearly so in form. H H' are double armed cranks or levers,
mounted on and secured respectively to the valve spindles A. A', having at one end
studs or projections h h¹. The studs travel in a circular arc. The other ends of
the cranks are coupled to springs in the case I. The ratchet teeth G G¹ may be
adjusted by means of the slots 9, Figure 3.
In action when the tooth G is advancing from left to right, its vertical face
engages at a certain point of its travel with the stud h, thus forcing the arm H to
one side and opening the valve more and more, until the arc in which the stud h
travels carries it clear of the face of the tooth G and the valve is thrown out of
gear.
When this disconnection takes place, the valve is instantaneously closed by
the action of the spring I, which spring may be cushioned by a small piston closing
on compressed air, if desired. In the meantime the chamfered face of the other
tooth G¹ has come in contact with the stud on the arm H', but the two faces
being chamfered they will on coming together cause the lever D' to be depressed,
the resiliency of the spring F enabling this to take place without operating the
lever H¹ at all. When the tooth G₁ has been carried clear of the stud h¹, the
lever D springs back to its original place. On the return stroke from right to left
the action is reversed, the tooth G'operating the valve A', while the tooth G is

page_text: depressed in passing the stud. In this way the valves are moved alternately by the
contact of the teeth G G with the studs hh.
From the above description, it will be obvious that the steam valves to which
the spindles A A' are attached are thrown out of gear during every stroke of the
engine. The instant however at which the said valves are thrown out of gear. an
the steam cut off, depends according to my invention on the position of the balls
of the governor at the moment, and thus an acceleration of speed works a
diminution of steam inducted and conversely. J represents the governor, K a pair
of symmetrically placed levers pivotted at ek on fixed pivots and their free ends
connected with the thrust rod N of the governor at K' (Fig. 1), or by the use of
straight and curved racks K' see Fig. 3 or by links. At the opposite en ls of those
levers are rollers L L which rest against the inclines d on the levers D D'. The
Jength of the arcs in which the studs hh' travel, depends on the depths of engage-
ment of the respective ratchet teeth and studs. The tendency of the spring Fis
to increase the depth of this engagement, but the tendency of the two roller L L
which roll on the inclines d is to diminish it when the governor balls rise, and they
regulate the moment at which the disengagement takes place. This as the speed
of the engine increases, the thrust rod N of the governor rises forcing the rollers L
against the inclines d, which depress the levers D and reduce the depth of engage-
ment of the ratchet teeth G G and studs h h. This reluces the length of the arc,
in which the studs travel, and consequently produces an earlier cut-off of the steam
by the valves. The cut-off is thus a variable one.
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. The improvement in valve gear for steam engines of the kind commonly
known as Corliss engines, whereby an acceleration of speed of the engine works a
diminution of steam inducted, and conversely, substantially as described.
2. A valve gear for steam engines of the kind usually known as Corliss engines,
in which a projection at the end of a crank of suitable radius rigidly attached to
each of the spindles which give motion to the oscillatory steam inlet valves and
adapted to move in a segmental circular path, is adapted to be so engaged at each
revolution of the engine by a tooth or stud formed on hinged arms reciprocating in
a straight line, as to open the valve to admit steam to the cylinder an I keep it open
until such time as the circular path in which the stud travels carries it clear of the
tooth, whereupon the valve is instantly closed by a spring or weights substantially
as set forth.
3. In combination with the matter set forth in Claim 2, the arrangement for
changing the position of the tooth on the arm relatively to the crank on the valve
spindle when any movement of the governor due to an acceleration in the speed of
the engine takes place, whereby an acceleration of speed of the engine effects an
earlier closing of the valve and consequently an earlier cut off, and conversely
substantially as described.
4. A variable trip gear for Corliss valves, in which a ralial arm, attached to the
valve spindle and capable of moving at its free end in a segmental circular path, is
operated recurrently by a hinged arm having normally a straight line motion, as
distinguished from the circular movement of the radial arm, but adjustable on its
axis in such a manner, that the governor will control its depth of engagement with
the radial arm, whereby the length of the are in which the radial arin travels will
be varied, and an acceleration of the speed of the engine effect an earlier cut off
and conversely, substantially as described.
5. In a variable trip gear for Corliss valves in which radial arms, attached to the
valve spindles and capable of moving at their free end in a segmental circular path,
are operated recurrently by hinged arms, the arrangement whereby the aforesaid
radial arm of the valve for admitting steam to one end of the cylinder and the
radial arm of the valve for admitting steam to the other end of the cylinder are

page_text: alternately operated, that is to say, the steam induction valve at one end of cylinder
is operated by the trip gear while the other remains at rest and vice versa,
substantially as described.
6. The general combined arrangement and construction of parts, substantially as
.herein before set forth.
Dated thie 11th day of December 1906
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.