Improvements in and relating to the Cut-off Valve Gear of Reciprocating Motive Power Engines.
Year: 1890

page_text: Date of Application, 14th Aug., 1890
Complete Specification Left, 13th May, 1891-Accepted, 14th Aug., 1891
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Cut-off Valve Gear of
Reciprocating Motive Power Engines.
I, SAMUEL MILNE, of Lower Buxburn, Auchmill, Aberdeenshire, Engineer,
do hereby declare the nature of my invention to be as follows:-
This invention has reference to and comprises improvements in and relating to
the cut-off valve gear of steam or other pressure fluid motive power reciprocating
engines, and to a special device in and for such cut-off valve gear, which will have
the effect of giving a true cut-off by the action of the governor equally from
opposite ends of the cylinder on the inward or outward stroke, proportionately to
the stroke of the piston, and the action of the governor below or above its normal
speed.
The nature and novelty of the improvements consist in the application and use
of a reciprocating bar, reciprocated in fixed guides, near the inlet steam, air or
other fluid cut-off valves and valve gear, proportionately to the motion of the
piston, and having equal angled or inclined sliding blocks or plates mounted on it
near its ends actuating levers or other equivalent, so as to disengage or cause the
valves to close and cnt off the steam or fluid in either valve equally, by the equal
reciprocation of these wedge blocks, which are actuated by equal length connecting
rods, attached to them at their outer free ends, and at their inner ends to opposite
cranks on a spindle carried in a bearing in the centre of the bar. This spindle
has a lever at right angles to the two levers of the connecting rods connected by a
rod to the governor, so that as the governor balls rise or fall above or below their
normal position and speed of the engine they would respectively oscillate the said
triple arrangement of T-levers to draw the connecting rod and angled plates
equally towards the centre of the bar and lever spindle or push them outwards
from said normal position of the levers to give the equal cut-off from either end of
the cylinder and bar simultaneously by the action of the angled plates and the
governor. Various arrangements of mechanism may be employed to reciprocate
the said bar carrying the angled slide blocks proportionately to and simultaneously
with the piston; and various arrangements of levers might be employed between
the governor and the said triple arrangement of levers and connecting rods to
reciprocate the angled blocks or plates on the said bar; and the angled blocks
might be made to actuate different arrangements of levers between them and the
cut-off valves to effect the cut-off. Thus according to one application, say as
applied to the Corliss inlet and cut-off valves of an engine, and which will illustrate
the nature of the improvements as suitable for being applied to the cut-off valves
of other engines, the bar might be mounted to reciprocate in guide brackets at
each end over the brackets carrying the projecting valve spindles, and actuating
and closing levers mounted on their outer ends. By one arrangement the bar might
be reciprocated by a connecting rod from a crank or eccentric on a light counter
shaft mounted at right angles to and in line with it in bearing brackets over the
frame between the cylinder and the crank shaft pillow block, this shaft being
actuated from the crank shaft by bevel gearing and one longitudinal shaft, with
bevel gearing at the end of this with the cross shaft, so as to be turned at the same
speed as and with its crank or eccentric set to rotate simultaneously and at the same
angle as the crank of the crank shaft, the crank or eccentric and connecting rod
actuating the bar being proportionate to those of the crank shaft, so that the bar
will reciprocate proportionately to the piston of the engine. The angled slide blocks
or plates would or might be mounted immediately over or at the side of each valve
spindle, and have the horizontal arm of a bell-crank mounted over each plate,

page_text: with its vertical arm made -fork-wise to take down into the centres of a shifting
ring in the boss of an actuating disc mounted by a key or feather on each valve
spindle, with a spiral or other spring on the spindle behind the boss, pressing it
always into gear with the driving disc and boss of the inlet steam lever mounted
loose on the spindle outside this cut-off driving disc, the two being connected by
segmental steel plates on each disc, which allows the loose disc and lever to open
the steam valve by the wrist" plate actuated by the eccentric of the engine,
another lever being mounted fast on the spindle connected by a rod with the closing
dash pot, which immediately cuts off the steam as the inclined blocks raise the
horizontal arm of the lever and disengage the driving disc from the steam lever
disc. The governor.by a beam lever or other equivalent acts on the T lever
arrangement of the bar to draw in or push out the angled blocks by the action of
the governor, and so release the cut-off mechanism and valves all in the improved
manner herein before described, proportionate to the motion of the piston from
either end of the cylinder, and which form the main clements of the invention and
improvements.
It will be obvious that the said bar might be reciprocated proportionately to the
piston of the engine, from a motion taken from the crosshead through a differential
arrangement of armed lever or levers, instead of the bevel wheel gearing herein-
before described. And also that the arrangement of T levers actuated by the
governor and carried on the bar for reciprocating the angled plates might be
modified; and different arrangements of levers actuated by these angled plates to
set free or actuate the cut off valves might be used, instead of the bell-crank levers
described, modified to suit the kind of cut-off valves employed.
Dated the 13th must 1800
W. R. M. THOMSON & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in and relating to the Cut-off Valve Gear of
Reciprocating Motive Power Engines.
I, SAMUEL MILNE, of Lower Buxburn, Auchmill, Aberdeenshire, 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, that is to say :-
This invention has reference to and comprises improvements in and relating to
the cut-off valve gear of steam or other pressure fluid motive power reciprocating
engines, and to a special device in and for such cut-off valve gear, which will have
the effect of giving a true cut-off by the action of the governor equally from
opposite ends of the cylinder on the inward or outward stroke, proportionately to
the stroke of the piston, and the action of the governor below or above its normal
speed.
And in order that the said invention and the manner of performing or carrying
the same into effect or practice may be properly understood, there is 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.
Figures 1 and 2 on Sheet 1 are a front side elevation and corresponding plan
respectively of the cylinder of a Corliss engine, showing the improvements of this
invention as applied thereto.
Figure 3 is a back end view corresponding to but at right angles to Figure 1.
Figure 4 shows detailed side, end view, and plan of part of the improved
reciprocating bar actuated by the engine and reciprocated in equal times pro-
portionally to the motion of the piston, and one of the slide blocks mounted on it
actuated by the governor, all to a larger scale than in Figures 1 to 3 to show the
details of construction more clearly than in these figures.

page_text: Figure 5 on Sheet 2 is a front side elevation, and Figure 6 a sectional end view,
at right angles to Figure 5, of the cylinder of a horizontal engine with slide valves
as fitted with these improvements.
Figure 7 is a sectional plan view corresponding to Figure 5, and Figure 8
a sectional plan view corresponding to Figure 6, to show the construction of
the slide valve, and the cut-off valve actuated by the new cut-off gearing.
Referring to these drawings generally, the improvements consist in the applica-
tion and use of a reciprocating bar A reciprocated in fixed guides A', near the
inlet steam, air, or other fluid cut-off valves and valve gear, proportionately to the
motion of the piston, and having equal angled or inclined sliding blocks or plates B
mounted on it near its ends to actuate levers or other equivalent, so as to dis-
engage or cause the steam valve or cut-off valve to close and cut-off the steam or
fluid through either valve equally by the equal reciprocation of these wedge
blocks B, which are actuated by equal length connecting rods attached to them
by journal stud pins at their outer free ends, and at their inner ends to opposite
arms or cranks of a three armed lever 1, on a stud spindle secured to the
centre of the bar A. The third lever at right angles to the two levers 16" of
the connecting rods is actuated through a rod and bell cranks to the governor,
so that as the governor balls rose or fell above or below their normal position and
speed of the engine they would respectively oscillate the said triple arrangement
of T-levers to draw the connecting rods and angled plates B equally towards
the centre of the bar A and lever spindle, or push them outwards from the said
normal position of the levers to give the equal cut-off from either end of the
cylinder and bar A, simultaneously by the action of the angled plates B and the
governor as the bar A was reciprocated. Various arrangements of mechanism
may be employed to reciprocate the said bar A carrying the angled slide blocks B,
proportionately to and simultaneously with the piston and various arrangements
of levers may be employed between the governor and the said triple arrangement
of levers and connecting rods to reciprocate the angled blocks or plates B
on the said bar A, and the angled blocks B might be made to actuate different
arrangements of levers between them and the steam inlet or cut-off valves to effect
the cut-off. Thus according to one application, say as applied to the Corliss inlet
and cut-off valves of an engine, as shown in Figures 1 to 4, on Sheet 1, and which
will illustrate the nature of the improvements as suitable for being applied to the
cut-off valves of this or analogous forms of engines, the bar A. may be mounted to
reciprocate in guide slides at A¹ at each end, over the brackets C carrying the
outer bearings of the projecting spindle C₁ of the ordinary Corliss inlet steam and
cut-off valves working in their casings at C2 in these figures. In this arrangement
the bar A is reciprocated by a connecting rod A" from a lateral pin in the disc or
crank A² on a light counter-shaft A³ mounted at right angles to and in line with it
in bearing brackets over the frame near the cylinder C, this shaft A³ being actuated
by bevel or mitre gearing A from one longitudinal shaft A, with mitre or bevel
gearing at the end of this with the crank shaft, so as to be turned at the same
speed as and with its crank A³ set to rotate simultaneously and at the same angle
as the crank of the crank shaft, the crank A and connecting rod A" actuating the
bar A, being proportionate to those of the crank shaft, so that the har A will
reciprocate proportionately to the piston of the engine. The angled slide blocks
or plates B would be mounted immediately over or at the side of each inlet valve
spindle C, and have the horizontal arm B' off a bell-crank B', B2, mounted in
brackets B over each plate B, with its vertical arm B2 made fork-wise to take
down into the collar eye or boss of a shifting disc B³ mounted by a key and feather
on each valve spindle, and which may have a spiral or other spring on the
spindle behind the boss, pressing it always into gear with the driving disc B of the
inlet steam lever mounted loose by its boss on the spindle C¹ outside this cut-off
driving disc, the two being connected by segmental steel plates at B or catches
on each disc, which allows the loose disc B and lever to open the steam valve by
the action of the connecting rods E' from the ordinary
";
wrist plate E and

page_text: eccentric on crank shaft of engine, a pine being secured on the disc B³ connected
by a spindle e' with the piston of the closing dash pot e2 which immediately cuts off
the steam as the inclined blocks B raise the horizontal arm B' of the lever B1, B2,
and disengage the driving disc B³ from the steam lever disc B. The governor by
a lever or other equivalent reciprocates the vertical rod with collar boss. on it,
up or down to draw in or push out the angled blocks B through the rods and
cranks to before mentioned, and so release the cut-off mechanism and valves
all in the improved manner hereinbefore described, proportionate to the motion
of the piston from either end of the cylinder, and which form the main elements of
the invention and improvements.
Referring to Figures 5 to 8 on Sheet 2, in which these improvements are applied
to the brander cut-off valves of a horizontal cylinder engine with double slide
valves, the arrangements of the intermediate gearing for working the reciprocating
bar A, in regular time with the crank shaft, and that for actuating the cut-off
brander valve C³ and its rod C regularly by a motion from the crank shaft, and
differentially from the governor, in proportion to the speed of the engine, are all
different from that shown in Figures 1 to 4 on Sheet 1, and are mainly carried on
two central side frames F, F', and two hollow side standard frames F, F³, bolted
at F to the upper horizontal web of the valve steam chest C³, having two slide
valves C each with steam inlet and exhaust chambers and ports cc' in them, both
reciprocated horizontally by their slide valve rod C* from an eccentric on the crank
shaft in the usual manner over steam inlet and exhaust ports C2 C" in each end of
the face plate of the cylinder one of which valves is shown in Figure 8. Each
brander valve C3 works vertically by dovetail slide grooved guides C on the
back steam inlet brander ports c, on the back of its slide valve C³ to admit the
steam to the steam chamber and port c of each valve when raised and opened, and
close the ports when raised by the reciprocating action of its rod C₁ which works
out through a stuffing box in the upper side of the valve chest C² in the lower
centre of each frame F", F, vertically up, and connected at its upper end e¹ to a
piston working in a close bored spring dash pot e jointed by flanges on their lower
ends to the top of the standard frames F", F2. These rods C', e', also work up in
the open space between the forked outer arms G of a double armed beam
lever G, G, carried by a long eye on central transverse spindles at G working in
journal bearings at G at the opposite sides of the two centre side frames F, F.
The inner arms G₁ of each of these levers G, G', have antifriction rollers G²
mounted on adjacent studs in them near the centre under and so as to be actuated
by two cut-off cams G³, G³, mounted on the shaft A5 in journal bearings in the
centre of the frames F, F. This shaft A is actuated from bevel or other gearing
from and at the same speed as the crank shaft, and by the spur wheels A' actuate
the crank shaft A³, carried in bearings in one side of the upper frames F, F, which
by the crank A and connecting rod A" and lateral pin A in the back of the
reciprocating bar A, reciprocates it in its fixed slide guides A¹ in the upper part of
the frames FF, in equal times and proportionate to the traverse of the piston.
The improved angled or bevel ended plates B in this case are reciprocated on
angled slides on the outer ends of the bar A by lateral pins, in front
differentially according to the speed of the governor, that is by the connecting
rods b, b attached to the two arms of the T or three armed lever ", carried
on the stud spindle." in the centre of the bar A and actuated by the rod from
the governor connected to the arm 2 of this lever substantially in the same manner
as described in reference to Figures 1 to 3 on Sheet 1. The forked ends G of each
of the levers G, G³, carry a short spindle g oscillating loose in bearing bushes at
with a central short vertical acting lever 2 on each, with a steel plate screwed on
its upper end, which acts on a corresponding steel plate e screwed at e" to the upper
end of each of the rods C¹ of the cut-off valve C³, and the acting lever g
and its plate is kept in the vertical acting position by another outward projecting
horizontal angled plate lever B keyed on each outer end of the spindles having
short heel levers B² pressed down by the outer end of strong blade springs D

page_text: screwed at D' to a lateral bracket formed on the front central part of the outer
frame F' seen more particularly in Figure 5.
The action of the cut-off mechanism in this arrangement is as follows:-When
the engine is going at its regular speed the cams G³, on the shaft A', rotate
regularly, and the raised parts of these cams acting on the antifriction rollers G
depress the inner arms G of the levers G G as the piston of the cylinder C and
slide valves C are travelling from opposite ends of the cylinder, and raise the
outer forked arms G, which through the blade springs D bring the plate arms 2
to the vertical position, as shown on the right hand side in Figure 5, to act on the
plate e and raise the cut-off valve rod C and brander valve to admit the steam
to the steam port of the valve for as long a time as the raised part of the cam is
acting, and with the outer plate arm B raised to the plane of the angled plate B,
so that if the engine runs away beyond its normal speed, the governor would by
the links and levers to , draw the plate B over the arm B' and depress it, and
so free the acting plates ate of the rod C and cut off the steam by the action of
the dash pot e² earlier than the cam G³ would do at either end of the cylinder and
motion of the slide valve. The levers G G and B are shown in their lower position
on the left hand side in Figure 5, that is as if the piston and valves were travelling
from the inner to the outer end of the cylinder.
It will be obvious that the said bar A might be reciprocated proportionately to
the piston of the engine, from a motion taken from the crosshead through a
differential arrangement of armed lever or levers, instead of the bevel wheel
gearing herein before described. And also that the arrangement of T levers
actuated by the governor and carried on the bar for reciprocating the angled plates
might be modified; and different arrangements of levers actuated by these angled
plates to set free or actuate the cut-off valves might be used, instead of the
Tlever Band bell-crank levers described, modified to suit the kind of
cut-off valves employed.
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 arrangement and combination of the parts and
mechanical motions of a cut-off valve gear of reciprocating motive power engines,
having a bar reciprocated in guides in the same times and proportionate to the
motion of the piston, with angled or inclined blocks or plates on it differentially
operated according to the speed of the governor to give any desired cut-off by the
steam or cut-off valves of the engine substantially as and in the manner herein
described in reference to and shown in the accompanying drawings.
Second. In a cut-off valve gear of reciprocating motive power engines, the
arrangement and use of a bar having angled or inclined sliding blocks or plates
on it operated differentially by the governor, and reciprocated in fixed guides in
the same times and proportionate to the motion of the piston, substantially as and
in the manner and for the purposes herein described, in reference to and by way
of application shown in the accompanying drawings.
Dated this 13th day of May 1891
W. R. M. THOMSON & CO.,
96, Buchanan Street, Glasgow, Agents.