IMPROVEMENTS IN STEAM- ENGINES
Year: 1883

page_text: LETTERS PATENT to Alexander Melville Clark of the firm of A. M and
W Clark of 53 Chancery Lane in the County of Middlesex Fellow of the
Institute of Patent Agents for an Invention of IMPROVEMENTS IN STEAM-
ENGINES communicated to him from abroad by William Farr Goodwin, of
Stelton, in the County of Middlesex, State of New Jersey, United States of
America
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 23rd May 1883.
"
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex Fellow of the Institute of Patent Agents,
"IMPROVEMENTS IN STEAM ENGINES Communicated to me from abroad by
William Farr Goodwin, of Stelton, in the County of Middlesex, State of New
Jersey, United States of America
My Invention relates to improvements in balancing and lubricating the valves
of steam engines, and to improved combinations and arrangements of mechanism
for actuating the induction valves so as to obtain a variable cut off, automatic or
otherwise.
The valves are of the cylindrical type and work in chambers across the cylinder
covers two at each end as near together as the piston rod will admit so as to obtain
a port almost as wide as the full internal diameter of the cylinder. The valve
chambers are of such form as to leave a space behind the valve large enough to
allow of the valve lifting from its seat and for the reception of oil or other
lubricant and provided with passages for the admission of steam to press on the
lubricant and keep the valve up to its seat. The valve may work on a cranked
spindle of rectangular section received in a longitudinal slot in the valve in such a
manner as to admit of the valve lifting from its seat to permit the escape of water
from the cylinder.
Or the valve may rock upon a stationary round spindle and
seat by steam pressure acting on pistons fitted in cylinders at
chamber, the piston rods being attached to the valve spindle.
be held up to its
back of the valve
To permit of the

page_text: valve lifting from its seat under undue pressure, the valve is connected to its
operative spindle through the medium of a coupling disc having feathers at right
angles to one another at opposite sides received in corresponding slots in the head
of the operative spindle and the end of the valve which are to be coupled.
In the case of locomotive engines, the valves are placed vertically so as to bring
the valve gear on top of the cylinders
The mechanism for oscillating the induction valves consists essentially of a
rocking beam coupled by connecting rods at its ends to the crank arms of the
valve spindles, the arrangement being such that each member or half of the beam
and its respective connecting rod act together as a toggle whereby a varying speed
is imparted, the cut off taking place when the valve is moving at its highest speed.
This rocking beam oscillates on a pivot which is movable in guides under the
control of the governor or of a band wheel as the case may be for varying the
point of cut off. The rocking beam has a third arm by which it is oscillated
through suitable gear actuated by the eccentric this arm being slotted to admit of
varying the effective length of the said arm and so varying the angular motion of
the rocking beam by shifting the centre of motion on which the beam works or
otherwise. According to one arrangement the centre of motion of the rocking
beam is shifted by a lever operated by the governor the other end of said lever
.being connected to the sliding block of the link motion from which the rocking
beam is operated for the purpose of adjusting said block in the link at the same
time that the centre of motion of the rocking beam is altered or independently or
one only may be movable. The said link may receive a simple or a compound
'motion through suitable levers and connections According to another arrangement
instead of having for the two valves one rocking beam acting together with the
two connecting rods as two toggles, I may employ two separate and distinct
toggles one for each induction valve the two toggles being operated by the same
connecting rod from a link motion. The exhaust valves may be operated by a
similar rocking beam or toggle, or by any other gear

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
23rd November 1883.
"
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex, Fellow of the Institute of Patent Agents
IMPROVEMENTS IN STEAM ENGINES." A communication to me from abroad by
William Farr. Goodwin of Stelton in the County of Middlesex, State of New
Jersey, United States of America.
My Invention relates to improvements in balancing and lubricating the valves of
steam engines, and to improved combinations and arrangements of mechanism for
actuating the induction valves so as to obtain a variable .cut off, automatic or
otherwise. The valves are of the cylindrical type and work in chambers across the
cylinder covers, two at each end. The mechanism for oscillating the induction
valves consists essentially of a rocking beam coupled to the crank arms of the
valve spindles, the arrangement being such that each member or half of the beam
and its respective connecting rod act together as a toggle whereby a varying speed
is imparted, the cut off taking place when the valve is moving at its highest speed.
This rocking beam oscillates on a point which may be movable in guides under the
control of the governor, or of a hand wheel, as the case may be, for varying the
point of cut off. The rocking beam has a third arm by which it is oscillated
through suitable gear actuated by the eccentric, the effective length of this arm
being capable of adjustment for varying the angular motion of the rocking beam
by shifting the centre of motion on which the beam works, or otherwise. Instead
of a single rocking beam and links acting together as toggles, distinct pairs of
toggles may be used. The induction and eduction valves are placed as near
together as the piston rod will admit so as to obtain a port almost as wide as the
full internal diameter of the cylinder. The valve chambers are of 'such form as to
leave a space bebind the valve large enough to admit of the valve lifting from its
seat and for the reception of oil or other lubricant and provided with passages
for the admission of steam to press on the lubricant and keep the valve up to its
seat.
In order that the Invention may be more readily understood I have illustrated
it in the accompanying drawings and will proceed to describe it with reference
thereto. Figure 1 is a side elevation partly in section of the cylinder and valve
mechanism of a horizontal engine wherein the cut off is varied automatically by a
governor. Figure 2 is an elevation of the cylinder and valve mechanism of a
marine engine wherein the cut off is varied by hand. Figure 3 is a side elevation
of a horizontal engine having a modification of the valve gear suited for large or
high speed engines. Figures 4 and 5 are side elevations of a horizontal engine
showing a further modification of the automatic valve gear on the same principle.
Figure 6 is a section of the cylinder and valves of the same engine. Figure 7 is a
side elevation of another engine provided with another modification of automatic
valve gear on the same principle. Figure 8 is a section of one end of a cylinder on
a larger scale provided with balanced valves similar to those in figure 6, and
Figure 9 is a longitudinal section of one of the valves showing its cranked spindle.
Figure 10 is a similar section to figure 8 showing a modified mode of balancing
the valves Figure 11 is a longitudinal section of one of the valves. Figures 12
and 13 are details of parts of the same on a larger scale Figure 14 is a front
elevation partly in section of a locomotive showing the position of the valves. The
same letters of reference indicate the same parts in all the figures. Referring to

page_text: Figure 1 V V are the induction valves and V V₁the exhaust valves.
The latter may be operated by a
about to be described applies only to the former.
similar rocking lever without adjustment. A is the rocking beam and B the links
coupling it to the crank arms C of the valve spindles. The beam is pivoted at a
in a bearing moveable in a vertical slot a' and carried by a rod a pivoted to the end
of the lever D. The lever A is T shaped its third arm A¹ being slotted to receive a
slide block e attached to the end of a rod E and supported in the slotted arm A¹ by
a radius link.e¹ pivoted to a fixed point. Thus arranged by raising and lowering
the centre of motion a of rock lever A the effective length of the arm A¹ is altered,
and the relative positions of the various centres of motion are likewise altered thus
varying the cut off. The lever D is pivoted at d receives motion from any suitable
governor for varying the position of the centre of motion of the rock lever A. The
other end of the rod E is connected to a slide block f received in a link F and
carried by rod fjointed to the other arm of lever D. The link F is in one with
an arm F¹ suppofted by a radius arm G jointed to it at F'. H is an eccentric rod
taking hold of the same wrist pin F2 and H' is another eccentric rod jointed to the
end of arm F¹ and receiving through suitable gear motion from the same eccentric
at an angle to the motion imparted to rod H thus imparting a compound motion to
the link F. The second element of this motion may be varied in any degree or
entirely dispensed with in which case the link F will work on the lower end of
arm F¹ as a centre; or the link motion may be entirely dispensed with, the lever A
then receiving its motion direct from the eccentric. With the complete arrangement
shown however the action is quicker.
The relative arrangement of the rock lever A connecting links B and crank
arms C of the valves is such that the angular distance travelled by the ends of the
rock lever A is much greater than necessary to open and close the valves, the
position of the parts at the moment of opening and closing either valve being such
that its connecting link B is at about right angles to the lever A and crank arm C,
the latter thus at this moment moving at the same speed as the end of the rock
lever A, while at other times when the valves are shut the motion of the lever A
is more or less lost on them by reason of the links B coming into and passing
across a straight line with the lever A. The valves thus have a high speed at the
moment of opening and closing without having an amount of travel which would
be commensurate with that speed if it were uniform:
Referring to the diagram of motion in Figure 1, line N° 2, represents the position
of lever A when the piston is at the beginning of its forward stroke; at this
moment the valve V at the back end of the cylinder is on the point of opening
and will continue to open until the lever A assumes the extreme position N° 1 in
which it is shown in full lines, at which time the valve is full open. By the return
motion of the lever A the valve is closed, when the lever arrives again at position
No 2 which is the position it occupied when the piston stroke commenced. During
these movements the valve V at the front end of the cylinder was moved in the
same direction as that in which it closes and back again. Both valves remain
closed until position N° 3 is reached which is the mean position of the lever, both
valves then covering the induction port to the same extent and with a long lap.
Upon the piston arriving at the end of its forward stroke the lever A assumes the
position No 4 when the induction valve at the front end of the cylinder is on the
point of opening and by the continued motion of the lever A is opened and closed
in the same way as was previously described in reference to the valve at the back
end which itself now receives a similar motion to that previously described in
reference to the valve at the front end.
It will be readily seen that varying the positions of the centres of motion
relatively to the valve centres, will vary the moment of cut off relatively to the
piston strokes. The varying of the position of the centre of motion of the lever A
is effected by the governor as before described. If this centre of motion be raised
the valves cut off earlier until the centre is. raised to its highest position when no
steam will be admitted, and if lowered the valves cut off later until steam is

page_text: admitted for the full stroke. It will be seen that when the centre of motion of
lever A is raised, the block f is lowered in link F, and vice versa, thus co-acting
with the variation of the effective length of the arm A¹ of the lever A to vary the
extent of motion of the lever A but as before mentioned either of these two
adjustments may alone be used.
¡
In Figure 2 the induction valves are operated by a rock lever A and connecting
rods B as before described, but the centre of motion of the rock lever is adjusted
by a screw operated by a hand wheel so that the cut off is variable but not
automatic. The exhaust valves are operated by a similar lever which is not
adjustable and both levers may be operated from link motions as shown, or other-
wise. For a cheap style of engine the rock lever A may be carried on a fixed
pivot when the cut off will be varied by varying its angular motion by means of
a slotted link as shown in Figure 3, or otherwise.
Figure 3 shows each of the inductions operated by a separate toggle. This
arrangement is suitable for very large or high speed engines, where a rocking beam
would be objectionable. The cut off adjustment can be effected by varying the
position of the pivots a and changing the throw of the movement.
Referring to Figures 4. 5. and 6, A is the rock lever, B the connecting links, and
C the crank arins of the induction valves V as before. The centre of motion of
the rock lever is suitably guided and is movable vertically as before. In this case
however the centre of motion has a constant rising and falling motion imparted
from the cross head of the engine by the lever D and connecting rods, the lever D
being in this case pivoted to a counterbalanced lever actuated by the governor
which thus varies the position of the range of motion of the centre of motion of
the rock lever, thus varying the cut off. Figure 5 is an elevation of the opposite
side of the engine showing the arrangement for working the exhaust valves by the
same eccentric, the position of the centre of motion of the rock lever which works
the exhaust valves not being varied. The construction of the valves shown in
Figure 6 will be understood by reference to Figure 8.
In Figure 7 the centre of motion of the rock lever A for the induction valves
has a constant motion imparted to it by the crosshead, as in Figure 5, but the
arrangement of the gear for imparting that motion is different and is so arranged
by means of a link K that the amount of that motion may be varied. The gear
for imparting the oscillating motion to the lever A has also a link L for varying
the extent of that motion, the slide blocks of both these links being adjusted by
the governor in opposite directions, thus varying the cut off.
Referring to Figure 8, the induction valves V, and eduction valves V¹ have a
chamber M behind them to allow the valves to lift from their seats and for the
reception of oil or other lubricant. N is a passage connecting these chambers M
with the steam supply for holding the valves to their seats. The valve has a
longitudinal slot O in which is received a cranked spindle of rectangular section P
in such manner as to admit of the valve lifting from its seat to permit the escape
of water from the cylinder. The form of this spindle is more clearly shown in
Figure 9 and the slot is enclosed by a cap behind the spindle, and a spring is
interposed between the valve and the cranked spindle to keep the valve up to its
seat when steam is off.
In Figure 10 the induction and eduction valves V V' each rock on a stationary
round spindle S which is received in an open V shaped groove in the back of the
valve and each valve is held up to its seat by steam pressure acting on pistons QQ
fitted in cylinders R R at back of the valve chamber, the piston rods q being
attached to the valve spindle S. To permit of the valve lifting from its seat under
undue pressure, the valve is connected to its operative spindle P through the
medium of a coupling disc T (Figure 12) having feathers t t¹ on opposite sides at
right angles to one another which are received in corresponding slots t2ts in a head
on spindle P and on the end of the valve respectively.
Figure 14 shows the position of the valves on the cylinder heads of a locomotive
engine. It will be seen that they are placed vertically and as close together as

page_text: the piston rod will admit so as to enable the valve gear to be placed on top of the
cylinders so as to obtain ports almost as wide as the full internal diameter of the
cylinder. The valves are operated by rock levers and other gear as before described.
It is preferred to make the inside valves the induction valves, but either the inside
or outside valves may be used for induction and by means of a suitable valve the
direction of the steam in the steam passages may be reversed, thus reversing the
engine without the use of a link motion.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
hereinbefore in part recited Letters Patent is.
1st In a steam engine the combination with a pair of oscillating induction valves
of a rock lever connected with the crank arıns of the valve spindles and mounted
on an adjustable centre of motion, substantially as herein described and shown in
the drawings for the purpose specified.
2nd The respective combinations and arrangements of variable expansion gear
for induction valves, substantially as herein described and illustrated respectively
in the different figures of the drawings.
3rd The respective constructions of cylindrical, oscillating, balanced, automatic-
relief valve, substantially as herein described and shown in Figures 8 to 13 of the
drawings.
4th The arrangement of the valves of a. locomotive engine vertically across the
cylinder covers, substantially as and for the purpose specified.
In Witness whereof I the said Alexander Melville Clark have here unto set my
hand and seal this twenty third day of November, A.D. 1883.
M CLAD IZ