IMPROVEMENTS IN STEAM ENGINES."
Year: 1869

page_text: LETTERS PATENT to Charles Alfred Marriott and Edward Holt, of
Newton Heath, near Manchester, in the County of Lancaster, for
the Invention of "IMPROVEMENTS IN STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said Charles Alfred Marriott
and Edward Holt at the Office of the Commissioners of Patents,
with their Petition, on the 27th December 1869.
We, CHARLES ALFRED MARRIOTT and EDWARD HOLT, of Newton
Heath, near Manchester, in the County of Lancaster, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN STEAM ENGINES,"
to be as follows:-
This Invention relates to that description of steam engine in which
there is a supplementary or cut-off valve working in connection with the
slide valve for the purpose of cutting off the supply of steam to the
cylinder at different parts of the stroke of the piston, and thus regulate
the expansive working of the steam according to its pressure or to the
load upon the engine, the steam being at full pressure or thereabouts
when admitted into the cylinder and expanded to the fullest extent, and
another part of the Invention relates to the slide valves of all descrip-
tions of steam engines.

page_text: Our Invention consists, first, in giving a positive motion to the
supplementary or cut-off valve from the same eccentric which works the
slide valve by the following improved arrangement of mechanical parts:
-To the ordinary eccentric rod or strap we joint at any required angle
a short rod connected to a link working on a stud fixed to the frame-
work or to a bracket, and place in the link a sliding block jointed to the
rod which works the supplementary or cut-off valve, and also to a rod
connected with the governor of the engine. When the engine is
exerting its greatest power the sliding block carrying the end of the
cut-off valve rod is at its greatest distance from the centre of vibration
of the link, and gives the greatest movement to the cut-off valve, but
when there is less load the governor moves the rod connected to it and
brings the end of the cut-off valve rod nearer the centre of vibration
and gives less motion to the cut-off valve to cut off the steam at a
shorter portion of the stroke, and when there is no load the end of the
cut-off valve rod is brought close to the centre of vibration and still
further cuts off the steam, and these motions are reversed when the load
is again put on, and as the parts are mechanically jointed and connected
together the movements are positive without any slipping whatever.
In another arrangement we employ two cut-off valves connected by
springs and having projecting lugs which can be held by hooks of two
pairs of clips and released from them, and between the valves there is a
block fixed to the centre of the slide valve and having at each side a
buffer, and the slide valve is worked by an eccentric or other well-known
means. When motion is given to the slide valve in one direction the
hooks of one pair of clips holds one of the cut-off valves by means of its
corresponding snug, and as the slide valve moves onward the slide port
at that end is opened, and also the cylinder port, for the admission of
steam, the buffer block stretching the springs and pushing back the
other or second cut-off valve between the other or second pair of clips,
and when the steam is to be cut off the first pair of clips are opened to
release the first cut-off valve, which then by means of the springs closes
up to the buffer on that side and cuts off the steam, and when the slide
valve is moved in the reverse direction the second cut-off valve is held
by the hooks of the second pair of clips until released to cut off the steam
at that end.
For cutting off the steam at any part of the stroke of the piston
we open the clips alternately by means of cams between them, or
by pinions fixed to their axes, and work the cams or pinions by levers

page_text: put in motion by a rod having double inclines, one end of the rod
communicating with the governor and the other end having vibrating
motion imparted to it by a rod communicating with any required part
of the rod or strap of the eccentric or other motion which works the slide
valve, the double inclines working the levers and cams or pinions sooner
or later. according to the position in which the inclines are placed by the
governor or by hand.
We modify this arrangement by connecting a crank to each cut-off
valve, the cranks being fixed to short shafts extending through the
steam chest cover and having at their outer ends arms which are held in
position by catches at the ends of inclines vibrated by a rod having one
end connected to the governor and the other end communicating with
the rod or strap of the eccentric, there being on the vibrating rod a
cross head which acts on the inclines and releases the arms from the
catches and allows springs to close the cut-off valves, the actions being
sooner or later according to the position of the cross head which is
raised or lowered by the governor or by hand, and in this modification
and the foregoing arrangement weights can be used instead of springs
to close the cut-off valves.
Our next improvement relates to the slide valve only, and consists in
constructing it so that it shall admit the steam in the usual manner, but
have at each end a passage to form an additional opening for the exhaust.
In the exhaust port of the cylinder we fix one or more supports carrying
a plate on which the upper part of the valve works as its lower part
slides to and fro on the facing of the ports of the cylinder, and form in
each end of the valve a passage extending first upwards and then
downwards, each passage being closed by the plate when the valve is
midway, but open to the interior of the valve and its corresponding
exhaust port when the exhaust takes place in the usual manner, and
thus at each end a double exhaust is obtained of such area that scarcely
any lan is required.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Alfred Marriott and Edward Holt in the
Great Seal Patent Office on the 27th June 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, CHARLES
ALFRED MARRIOTT and EDWARD HOLT, of Newton Heath, near Man-
chester, in the County of Lancaster, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of December, in
the year of our Lord One thousand eight hundred and sixty-nine, in
the thirty-third year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto us, the said Charles Alfred Marriott and
Edward Holt, Her special license, that we, the said Charles Alfred
Marriott and Edward Holt, our executors, administrators, and assigns,
or such others as we, the said Charles Alfred Marriott and Edward Holt,
our executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereatter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"LAPROVEMENTS IN STEAK ENGINES," upon the condition (amongst others)
that we, the said Charles Alfred Marriott and Edward Holt, our
executors or administrators, by an instrument in writing under our, or
one of our hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that we, the said Charles Alfred Marriott and
Edward Hoit, do hereby declare the nature of our said Invention, and
in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement (that is to say):-
One part of our improvements relates to that description of steam
engine in which there is a supplementary or cut-off valve working in
connection with the slide valve for the purpose of cutting off the supply
of steam to the cylinder at different parts of the stroke of the piston,
and thus regulate the expansive working of the steam according to its
pressure or to the load upon the engine, the steam being at full pressure
or thereabouts when admitted into the cylinder and expanded to the
fullest extent.
And another part of the improvements relates to the short slide valve
used in many descriptions of steam engines.
Our Invention consists, first, in giving a positive motion to the
supplementary or cut-off valve from the same eccentric which works the
slide valve by various improved arrangements of mechanical parts; and,

page_text: secondly, in constructing the slide valve so that it shall admit the steam
in the usual manner, but have at each end an additional opening for the
exhaust.
The manner in which our Invention is to be performed will be clearly
understood by the following particular description thereof, reference
being had to the figures and letters on the accompanying Sheet of Draw-
ings, in which Fig. 1 is a longitudinal elevation, and Fig. 2 a plan with
part in section representing the application to a horizontal steam engine
of one of our improved arrangements for giving positive motion to the
supplementary or cut-off valve; Fig. 3 is a longitudinal elevation of a
modification of the same; Figs. 4 and 5 are longitudinal and transverse
sections, and Fig. 6, a plan of another of our improved arrangements
for working the cut-off valve; and Figs. 7 and 8 are longitudinal and
transverse sections of our improved slide valve having additional open-
ings for the exhaust.
In Figs. 1 and 2, a represents the cylinder of the engine; b, the steam
chest; c, the crank shaft; d, the eccentric; and e, the eccentric strap;
and in Fig. 2 the slide valve is marked f and the supplementary or cut-
off valve g. The slide valve f is worked by one of the ordinary modes,
its rod being attached to a connecting rod jointed to one arm of a
double lever, the other arm of which is jointed to the eccentric rod fixed
to the eccentric strap. To give positive motion to the supplementary or
cut-off valve g we joint to the eccentric strap e at any required angle a
short rod h connected to one arm of a double lever i, j, and working on
a stud k fixed to the bracket . The arm j has in it a slot m in which
is placed a sliding block n jointed to the connecting rod o attached to
the rod p fixed to the cut-off valve g, and to the sliding block is linked
one end of a short rod q having its other end connected to
slider fitted in guides fixed to the bracket 2, and the slider is
connected to the governor of the engine in any desired manner. As the
eccentric d revolves the slide and cut-off valves f, g, move at different
times, and when the engine is exerting its greatest power the sliding
block n attached to the connecting rod o is at its greatest distance
from the centre of the stud k or centre of vibration, and gives the
greatest movement to the cut-off valve g, but when there is less load
the governor moves the slider so as to bring the sliding block n nearer
the centre of vibration and give less motion to the cut-off valve to cut
off the steam at a shorter portion of the stroke. When there is no load
a

page_text: the end of the cut-off valve rod is brought close to the centre of vibration
and still further cuts off the steam, but when the load increases the
sliding block n again moves further from the centre of vibration, and
the movements alternate according to the pressure of the steam and
variation of the load.
In Fig. 3 we represent a slight difference in the mode of working the
cut-off valve; for instead of attaching the valve direct to the valve
rod p, Fig. 2, we connect it to a lever s, Fig. 3, worked by another
levert connected to the cut-off valve rod u, the rod being attached to
a sliding block in the slot of a double lever w, x, connected by a rod y
to the eccentric strap 2, and raised up and down according to the load
and the pressure of steam in the same manner as the connecting rod o
attached to the cut-off valve rod p, Figs. 1 and 2.
In Figs. 4, 5, and 6 we represent an improved mode of working a
multi-ported or gridiron cut-off valve. To the slide valve a¹ we pivot
a three-armed lever b¹; c, d, having its central arm c¹ linked to the
cut-off valve e¹, and the other arms carry bowls f¹, g¹. In the cover of
the steam chest there are guides, into which is fitted a slide h¹ attached
to one end of a rod ¹, the other end of which is connected to a sliding
block in a slotted lever worked by a rod jointed to the eccentric strap
in the same manner as before described for the former Figures, and on
the slide h¹ there are two inclines l', m³, which with the slide have a
variable motion imparted to them by the action of the governor
according to the load and the pressure of steam. As the slide valve a¹
moves to and fro it carries with it the three-armed lever and cut-off
valve, and according to the position of the slide h¹ the bowls f¹, g¹, are
alternately acted upon by the inclines l¹, m³, and cause the central
arm c¹ to move the cut-off valve and close the ports at one end and open
those at the other end alternately and cut off the steam as required.
The bowls f, g, may be placed on studs fixed to the cut-off valve and
the inclines formed at the ends of the arms b¹, d¹, and in all cases
instead of employing the governor to regulate the cut-off the sliding
blocks can be set to any required position in the slotted levers by hand.
The second part of our Invention, shewn in Figs. 7 and 8, consists in
constructing the short slide valve of steam engines so that it shall admit
the steam in the usual manner, but have at each end an additional
opening for the exhaust. To the sides of the slide valve o' we fix
tops carrying a plate q' having legs or
plates p' having inclined

page_text: brackets placed in the exhaust port t¹ of the cylinder u', and on the
plate the upper part of the valve o' works as its lower part slides to
and fro on the facing of the ports of the cylinder, and on each end of
the valve we form a passage v' extending upwards horizontal and
downwards, each passage being closed by the plate q' when the valve
is midway, but open to the interior of the valve and its corresponding
exhaust port when the exhaust takes place in the usual manner, and
thus at each end a double exhaust is obtained of such area that scarcely
any lap is required.
Having now described the nature and particulars of our said Inven-
tion, and the manner in which the same is to be performed, we desire it to
be understood that in steam engines having supplementary or cut-off
valves, we claim,―
First. The mode of giving a positive motion to the supplementary or
cut-off valve from the same eccentric which works the slide valve by
means of a short rod connected at one end to the ordinary eccentric
strap at any required angle to the ordinary eccentric rod and at the
other end to a slotted lever or its equivalent.
Secondly. The improved mode of working the multi-ported or gridiron
cut-off valve.
And, thirdly. The improved mode of giving the short slide valve an
additional opening at each end for the exhaust, as all such improvements
are herein described and illustrated in the accompanying Sheet of
Drawings.
In witness whereof, we, the said Charles Alfred Marriott and
Edward Holt, have hereunto set our hands and seals, this Twenty-
fifth day of June, in the year of our Lord One thousand eight
hundred and seventy.
CHARLES ALFRED MARRIOTT. (L.S.)
EDWARD HOLT.
(L.S.)