IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES, AND IN APPA- RATUS CONNECTED WITH OR OPERATING THE SLIDE VALVES OF STEAM ENGINES
Year: 1864

page_text: ETTERS PATENT to Henry James Hogg King, of Cains Cross, Stroud,
in the County of Gloucester, Hubert Ellis Smith, of Upton Bishop, in
the County of Hereford, Engineers, and Joseph Bennett Howell, of
Sheffield, in the County of York, Steel Manufacturer, for the Invention
of "IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES, AND IN APPA-
RATUS CONNECTED WITH OR OPERATING THE SLIDE VALVES OF STEAM ENGINES."
the County of Hereford, Engineers, and Joseph Bennett Howell, of
Sheffield, in the County of York, Steel Manufacturer, for the Invention
of "IMPROVEMENTS IN THE SLIDE VALVES OF STEAK ENGINES, AND IN APPA-
RATUS CONNECTED WITH OR OPERATING THE SLIDE VALVES OF STEAM ENGINES."
Sealed the 16th June 1865, and dated the 19th December 1864.
PROVISIONAL SPECIFICATION left by the said Henry James Hogg
King, Hubert Ellis Smith, and Joseph Bennett Howell, at the Office
of the Commissioners of Patents, with their Petition, on the 19th
December 1864.
We, HENRY JAMES HOGG KING, of Cains Cross, Stroud, in the County of
Gloucester, HUBERT ELLIS SMITH, of Upton Bishop, in the County of
Hereford, Engineers, and JOSEPH BENNETT HOWELL, of Sheffield, in the
County of York, Steel Manufacturer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES
AND IN APPARATUS CONNECTED WITH OR OPERATING THE SLIDE VALVES OF STEAM
ENGINES," to be as follows:-
Our Invention relates, first, to improvements in slide valves of steam
engines, by means of which, although the steam be admitted throughout the
whole of the stroke of the engine, or be cut off at a quarter stroke or even less,
the eduction in either case remains open throughout nearly the full length of
Price 1

page_text: the stroke, and therefore obviates the objectionable back pressure always
resulting from working expansively with one slide valve. To effect this we
employ what may be termed a double valve, being one valve within another,
but the outer one only of which is. driven by the valve rod as usual; the inner
valve is of such length as will cover internally one of the steam ports to the
cylinder and the eduction port: this inner valve is disposed within the cavity
of the outer one, and fits accurately therein sideways, but is considerably
shorter than the cavity, and so that it has a traverse within said cavity. Now
supposing that the main port of the valve has considerable lap, that is to say,
is of such length externally that it cuts off the steam from one end of the
cylinder at, say, a quarter stroke, so that the two steam ports will always be
under the valve for three-quarters of the stroke. When steam is first admitted
by the valve it at the same time that it enters the cylinder passes between
the end of the cavity in the main valve and the end of the inner valve, and
forcing such inner valve towards the opposite end, thereby at once placing
the port at the other end of the cylinder in connection with the eduction, and
which remains so the whole of the stroke or nearly so; the action of the
steam at the opposite end of the valve is precisely similar. The thickness of
the end or inner and outer valves when together is just a little more than the
port, which it must cover for as short a period of time as possible. Instead
of employing an inner valve in the cavity of the slide valve, as before described,
we can recess two plates into the face against which the valve works,
and connect such plates with a small steam cylinder operated by the steam,
which has the effect of traversing such plates so as to open the exhaust at
the opposite end immediately, as before described. These plates are inlaid,
as it were, between the steam ports, and have the exhaust midway between
them. The steam passages to the small cylinder are crossed, that is to say
the steam passes from a steam port to the end of the small cylinder furthest
from such port to produce the desired motion in the plates, which are provided
with stops to regulate the traverse as desired.
The second part of our Invention relates to apparatus for moving the eccen-
tric or crank pin by which the slide valve of a steam engine is operated, so
that the eccentricity shall be more or less, and give more or less throw to
the valve, and also to traverse it to an opposite or nearly opposite point of the
shaft, and so reverse the action of the engine, as well understood. For this
purpose we fit a dovetailed slide across the end of the engine shaft, a little
out of the centre; this slide carries a crank pin, to which the valve rod is
attached. On the shaft we place a loose disc or plate immediately behind
the slide, such disc having a snail groove or grooves on its face; projections

page_text: from the back of transverse dovetailed sliding piece take into the snail
grooves. The snail disc revolves with the shaft, and so long as no extraneous
cause operates, the crank or eccentric will continue to operate with uniformity.
Supposing it is desired to reverse the engine while it is in motion it is simply
necessary to stop the rotation of the disc by the hand or other means, when
the eccentric or crank pin will be traversed to the position required for that
purpose. By adjusting the eccentric or crank pin with more or less throw,
the steam can be worked more or less expansively. We also render this snail
disc available to operate in connection with a governor, which is driven as
usual, while a band from a cone pulley on the governor axis controls the snail
disc. If the engine goes at proper speed, the cone pulley drives the disc at
same speed as the engine shaft; whereas if the engine goes too fast, the cone
pulley imparts a less speed to the disc than the shaft has, consequently the
snail will operate and give the crank or eccentric less throw, and cut off the
steam at an earlier period of the stroke; on the contrary, if an engine goes
too slow, the cone pulley drives the snail disc faster than the shaft, and so
shifts the eccentric or crank as to give the engine more steam, and there-
fore work less expansively. In working the second slide valve when a pair of
engines are in combination, we connect a rod with the same crank pin or
eccentric leading therefrom at right angles to the direction (direct to the
valve) of the other valve rod, and transmit the motion by crank arms, and
through a rocking shaft to such second valve and engine.
The third part of our Invention relates to other apparatus for traversing
the eccentric pin or part that operates the slide valve across the shaft for the
purpose of reversing the engine, or for working more or less expansively.
We fit the crank pin in a dovetailed slide across the end of the shaft, and
parallel with the slide is a screw rod; on this screw are two bevil
pinions, one in gear with an equal toothed pinion on a stationary hand wheel
placed loose on the engine shaft, the other (rather less in diameter) being in
gear also with an equal toothed pinion on the engine shaft. The rotation of
the bevil pinions on the screw, if not in unison, are calculated
to propel the screw rod in the direction of its length; the ends of this screw
rod being in connection with the dovetailed slide, it will be traversed at same
time; so long as the hand wheel remains stationary the two pairs of bevil
pinions will rotate at same velocity and maintain an equilibrium, so to speak,
between the whole, and no traverse of the screw rod will take
place, but so soon as the hand wheel is rotated in the one direction or the
other a differential motion will be induced between the bevil pinions, having
the effect of traversing the screw rod through them, and in a direction

page_text: across the axis or shaft, and so move the eccentric or crank pin as may be
desired. If only a little more or less lap or motion is to be given to the
valve a slight movement of the hand wheel will suffice; while if the engine is
to be reversed considerable motion must be given to the hand wheel, and such
as will traverse the crank pin actuating the valve to the opposite side of the
shaft, as well understood.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry James Hogg King. Hubert Ellis Smith, and Joseph
Bennett Howell in the Great Seal Patent Office on the 19th
June 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HENRY
JAMES HOGG KING, of Cains Cross, Stroud, in the County of Gloucester,
HUBERT ELLIS SMITH, of Upton Bridge, in the County of Hereford, Engi-
neers, and JOSEPH BENNETT HOWELL, of Sheffield, in the County of York,
Steel Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of December, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said Henry James Hogg King, Hubert Ellis Smith, and Joseph Bennett
Howell, Her special licence that we, the said Henry James Hogg King,
Hubert Ellis Smith, and Joseph Bennett Howell, our executors, adminis-
trators, and assigns, or such others as we, the said Henry James Hogg
King, Hubert Ellis Smith, and Joseph Bennett Howell, our executors,
administrators, and assigns, should at any time agree with, and no others,
from time to time, and at all times thereafter 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 "IMPROVEMENTS IN THE SLIDE VALVES OF
STEAM ENGINES, AND IN APPARATUS CONNECTED WITH OR OPERATING THE SLIDE
VALVES OF STEAM ENGINES," upon the condition (amongst others) that we,
the said Henry James Hogg King, Hubert Ellis Smith, and Joseph Bennett
Howell, our executors, or administrators, by an instrument in writing under
our, or their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same

page_text: 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 Henry James Hogg King, Hubert
Ellis Smith, and Joseph Bennett Howell, do hereby declare the nature of our
said Invention, and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement, refer-
ence being had to the two Sheets of Drawings hereunto anuexed, and to the
letters and figures marked thereon (that is to say):
Our improvements relate, first, to slide valves of steam engines, and are
such that although the steam be admitted throughout the whole of the stroke
of the engine, or be cut off at a quarter stroke, or even less, the eduction in
either case remains open throughout the full length of the stroke, and therefore
obviates the objectionable back pressure always resulting from working expan-
sively with one slide valve. To effect this we employ what may
be termed a double valve, being one valve within another, but the outer one
only of which is driven by the valve rod as usual; the inner valve is of such
length as will cover internally one of the steam ports of the cylinder and
the eduction port; this inner valve is disposed within the cavity of the outer
valve and fits accurately therein sideways, but is considerably shorter than the
cavity, and so that it has a traverse within said cavity. Now supposing that
the main part of the valve has considerable lap, that is to say, is of such
length externally that it cuts the steam off from one end of the cylinder at,
say, a quarter stroke, whereby the two steam ports will always be under the
valve for three-quarters of the stroke. When steam is first admitted by this
compound valve, it at the same time that it enters the cylinder passes between
the end of cavity in main valve and the end of the inner valve, forcing such
inner valve towards the opposite end, thereby at once placing the port at the
other end of the cylinder in connection with the eduction, and which remains
so during the whole of the stroke, or nearly so; the action of the steam at the
opposite end of the valve is precisely similar. The thickness of the ends of
inner and outer valves when together is just a little more than the depth of
the port, which must be covered for as short a period of time as possible.
Instead of employing an inner valve in the cavity of the slide valve, as before
described, we can recess two plates into the face, against which the valve
works, and connect such plates with a small steam cylinder operated by the
steam when it first enters the port of the main cylinder, which has the effect
of traversing such plates, and so affecting them as to open the exhaust at the
opposite end immediately, as before described. These plates are inlaid, as

page_text: it were, between the steam ports, and have the exhaust midway between
them.
The second part of our Invention relates to apparatus for moving the
eccentric or crank pin, by which the slide valve of a steam engine is operated,
so that the eccentricity shall be more or less, and give more or less throw to
the valve and also to traverse it to an opposite or nearly opposite point of the
shaft, whereby to reverse the action of the engine, as well understood. For
this purpose we fit a dovetailed slide across the end of the engine shaft a little
out of the centre; this slide carries a crank pin, to which the valve rod is
attached. On the shaft we place a loose disc or plate immediately behind the
slide, such disc having a snail groove or grooves on its face; projections from
the back of the transverse dovetailed sliding piece take into the snail grooves.
The snail disc revolves with the shaft, and so long as no extraneous cause
operates the crank or eccentric, it will continue to operate with uniformity.
Supposing it is desired to reverse the engine while it is in motion, it is simply
necessary to stop the rotation of the disc by the hand or other means, when
the eccentric or crank pin will be traversed to the position required for that
purpose. By adjusting the eccentric or crank pin with more or less throw
the steam can be worked more or less expansively. I also render this snail
disc available to operate in connection with a governor, which is driven as
usual, while a band from a cone pulley on the governor axis controls the snail
disc. If the engine goes at proper speed the cone pulley drives the disc at
same speed as the engine shaft, whereas if the engine goes too fast, the cone
pulley imparts a less speed to the disc than the shaft has, consequently the
snail will operate and give the crank or eccentric less throw, and cut off the
steam at an earlier period of the stroke; on the contrary, if the engine goes
too slow, the cone pulley drives the snail faster than the shaft, and so shifts
the eccentric or crank as to give the engine more steam, and therefore works
less expansively. In working the second slide valve when a pair of engines
are in combination, we connect a rod with the same crank pin or
eccentric, leading therefrom at right angles to the direction of the other valve
rod (the one direct to the valve), and transmit the motion by crank arms and
through a rocking shaft to such second valve and engine.
The third part of our Invention relates to other apparatus for traversing
the eccentric pin or part that operates the slide valve across the shaft for the
purpose of reversing the engine, or for working more or less expansively.
We fit the crank pin in a dovetailed slide across the end of the shaft, as before
described; through the end of the shaft and parallel with the slide is a screw
rod; in this screw are two bevil pinions, one in gear with an equal toothed

page_text: pinion on a stationary hand wheel placed loose on the engine shaft, the other
(rather less in diameter) being in gear also with an equal toothed pinion on
the engine shaft. The rotation of the bevil pinions on the screw if not in unison
are calculated to propel the screw rod in the direction of its length, the ends
of this screw rod being in connection with the dovetailed slide it will be
traversed at same time, so long as the hand wheel remains stationary the two
pairs of bevil pinions will rotate at same velocity, and maintain an equi-
librium, so to speak, between the whole, no traverse of the screw rod will
take place, but so soon as the hand wheel is rotated in the one direction or
the other a differential motion will be induced between the bevil pinions,
having the effect of traversing the screw rod through them, and in the direc-
tion across the axis or shaft of engine, and so move the eccentric or crank pin
as may be desired. If only a little more or less lap or motion is to be given to
the valve, little movement of the hand wheel will suffice, while if the engine
is to be reversed considerable motion must be given to the hand wheel, and
such as will traverse the crank pin actuating the valve to the opposite side or
nearly opposite point of the shaft, as well understood.
DESCRIPTION OF DRAWINGS.
Fig. 1, Sheet 1, represents an elevation, and Fig. 2 a plan of a horizontal
double cylinder engine, in connection with which some of our improvements
are represented. Fig. 2 shows the valve case and valves in longitudinal section
exhibiting our improved arrangement of double expansion valve.
a, a, is the ordinary slide valve, worked by the valve rod K in the usual
manner, while c, c, is the second valve. which is filled sideways, and at back
accurately within the cavity of the valve a, but in length is considerably less
than said cavity, and having a small V-shaped space between the ends when
abutting in either direction, as seen. This inner valve c has no separate or
special rod, or other connection, but depends for its motion on the working of
the valve a, and the steam pressure which traverses it towards the opposite
end immediately steam is admitted to either end of the cylinder, which has
the effect of opening the eduction simultaneously therewith, and allowing it to
remain open during the greater part of the stroke, although the steam may be
cut off at a quarter or other fractional part of the stroke, as herein-before
explained.
The second part of our Invention, which relates to apparatus for varying
or altering the position of the eccentric or crank pin by which the slide valve
or valves are driven, & whereby the extent of motion is to be regulated, or the
motion reversed, is also illustrated in Figs. 1 and 2. In this arrange the valve

page_text: rods are represented as being driven from a crank pin d; this crank pin is
fixed in a dovetailed sliding-piece e dovetailed into part f. fixed or formed on
the crank shaft g; the dovetailed socket in fis across (or nearly so) the axis
of the shaft in which direction part e slides; it has feathers or projections j, j
on the back part, which take into a snail groove h cut in the hand disc H,
which is mounted loosely on the shaft. This disc H if not acted on by any
extraneous means rotales at same velocity as the shaft, and the crank pin d
maintains the same radius. In the position shown the crank pin is at its
extreme radius, giving the valve its greatest extent of motion, consequently
admitting steam throughout the length of the stroke. If it is desired to give
the valve less motion it is simply necessary to impart rotation by hand to
the disc H at a little quicker rate than the motion of the main shaft g, which
will cause the snail groove to operate on the feathers i, j, of part e, and
traverse it a greater or less distance in the radial direction. If it is desired
to reverse the engine it is simply necessary to traverse the slide e, so that the
crank pin d will pass across the axis to the opposite side of the shaft g. To
move the crank pin from a lesser to a greater radins it is simply necessary to
retard the motion of disc II, and so allow the shaft g to run a little quicker than
the disc, the effect of the snail groove being to traverse the slide e as desired.
In Figures 1, 2, and 3 (the latter Figure shewing a detached view of the
governor) we have represented the disc H as being under the control of the
governor I. The governor is driven by strap k from a pulley fixed on
the shaft gas usual; the pulley 1, which communicates with the governor
shaft by bevil wheels m, is in two parts, the one parallel and constant, with
which strap communicates, the other taper, on which the strap p may be
traversed sideways; this strap encircles taper pulley n. by which it is
driven, and pulley o fixed on the back of disc H. The sirap guide q encircles
the strap p it is fixed on a stem r sliding in a suitable bearing, and is
operated by crank levers from the governor. When the engine is going at
its medium&proper speed the strap p maintains a medium position on the
conc pulley n, while if its speed be increased the strap is traversed to the
small part of cone pulley n, which then drives the disc H at a slower rate
than the shaft g, consequently reducing the radius of the crank pin d, and so
giving less steam to the engine. On the other hand, if the engine goes too
slow, the strap p is traversed to the large part of cone pulley n, which causes
the disc H to be driven at a quicker rate than the shaft g, thereby increasing
the radius of pin d, and so admitting more steam to the engine. When the
strap p is in a medium position on the pulley n, the motion imparted to disc H
will be uniform with that of the crank shaft g..

page_text: It will be observed, that in the double cylinder engine, represented in Figs. 1
and 2, the cranks are set at right angles as usual, but that both valves are"
driven by one and the same crank pin d. The one slide is driven by a con-
necting rod K directly from the crank pin, the other by a connecting rod L
led from the pin d in a direction at right angles to rod K, the motion being
transmitted thence to the valve of the other cylinder through a rocking shaft M
and its armis N and rod P, which imparts the requisite motion to the valve,
thus obviating the use of two cranks d or two eccentrics, as usually adopted;
the same operations may be effected by an eccentric adapted to the apparatus
before described.
. Fig. 4 represents a side view of an eccentric and cross section of an engine
crank shaft and valve rods arranged to produce the effects herein-before
described with reference to the crank pin d, while Fig. 5 is a plan of the
same. The eccentric R has a large slot across its diameter, or nearly so,
which slot is fitted on a square block or part S on the crank shaft. A
screwed pin or rod U is fitted to lugs on the eccentric; on this rod U a
pinion V is fitted; this pinion is socketted into part S, so that it rotates
freely in but cannot lift therefrom. A toothed wheel W fitted loose on
shaft g gears with pinion V; this wheel is of a piece with stap pulley of
driven by strap p from cone pulley, as before described. When the engine
is going too fast the wheel W rotates pinion V, so as to traverse the eccentric
across its diameter (the bolt or screw rod U slips freely through S), so
rendering it of more or less eccentricity, and therefore imparting more or less
motion to the valve rods. The reverse action of the cone pulley gives a
traverse to the eccentric so as to produce the opposite effect on the valve, all
as before described.
Fig. 6 represents an arrangement of apparatus according to our Invention
for operating the valve gear, more particularly adapted for screw propeller
engines; Fig. 7 is a longitudinal vertical section of Fig. 6. A is the main
shaft, and B the main bearing of the same; C is a stem piece fixed in the
shaft A; part C carries a dovetail guide D, in which a dovetail piece E is
fitted to slide in the direction of its length; this is disposed relatively to the
axis of engine shaft A, in same position as that in Fig. 1, and like it carries a
crank pin F, which communicates the motion to the valves; E has two arms G,
in which are fitted a screw rod X; this rod passes through C, and is fitted
with two bevil pinions 1, 2, the one (1) being screw fitted on the rod while the
one (2) slides loosely thereon, but has a feather, which slides in the groove
of X, causing it to rotate therewith; the pinion 1 revolves independently of
pinion 2, and has a socket or sleeve piece passing through a bearing in C, in

page_text: which it is free to rotate. Bevil pinion 1 gears with bevil pinion 4, fixed on a
round part of C, while pinion 2 gears with bevil pinion 5 fitted loosely on the neck
of 4; pinions 1 and 2 have an equal number of teeth, as also pinions 4 and 5.
In one piece with pinion 5 or fixed thereto may be a hand wheel Z, as shown
in red; in this case the hand wheel may either be held fast and prevented
rotating, or it may rotate freely with the shaft A; in either case no effect is
produced on the part E, as when the wheel Z is held fast, motion will be
given to wheel 2 by gearing with wheel 5, wheel 2 carrying screw round
with it.
It was mentioned that pinion 4 is fitted loosely on C, but it is fixed to a
collar 6. When hand wheel Z is fixed collar 6 is also held fast by slipping.
a bolt mounted on the bearing of frame into one of the holes 7. The rotation
of pinion with the axis C will produce a rotation on its own axis by reason
of its gearing with pinion 4 (which is bolted, as above-mentioned,) and will
neutralize the effect of the rotation of wheel 2 on screw rod X, which will
therefore maintain the same relative position. Supposing it is desired to vary
the position of screw X, and with it the crank pin F, the hand wheel Z, and
with it the wheel 5, is to be turned in the same or in an opposite direction to
that of the rotation of the shaft A, G; the pinion 2 will then receive a motion
at a velocity greater or less than the motion of pinion 1, which will result in
a differential motion being imparted to screw X, and consequently a shifting
of the crank pin F to a position having greater or less throw or eccentricity,
and such as may be desired; the same action will have the effect of traversing
the pin F across the diameter in order to reverse the engine.
We have represented the hand wheel Z as being fixed on pinion 5, but for
screw propeller engines and vessels going long voyages we prefer to mount
the hand wheel on a separate shaft as at J, J, Fig. 6. This shaft is fitted in
bearings fixed on the framework of the engine. It is free to slide endwise in
its bearings, and its end to slide into one of the holes 7, to act as a bolt to
arrest the rotation of pinion 6 with shaft A, C, as before mentioned. A
pinion 8 fixed on shaft J at same time gears with teeth 9 formed on the back
of pinion 5 or fixed thereto. The hand wheel so applied will operate on the
bevil gearing in same manner for altering or reversing the valves as the
wheel Zaforesaid, but has this advantage, that shaft J may be withdrawn
from 7 and so release it, as also pinion 8 from 9, which will allow the whole
of the gear to rotate while at work, and no alteration of the valves is required,
thereby obviating tear and wear in long voyages. This may be the case with
wheel Z in red, by allowing it to rotate with the main shaft, as also pinion 4
by withdrawing the bolt or fixture therefrom (from hole 7). Two connecting

page_text: rods are applied to the crank pin F, one led away at right angles to the
other, and the motion and power transmitted through a rocking shaft and
crank arms as before described.
Figs. 8, 9, 10, and 11 represent different views of a modification of our
apparatus last herein described, in which the differential gear is applied to
operate an eccentric. Fig. 8 is a side view of the eccentric; Fig. 9 is an end
view, showing the hand wheel; Fig. 10, a plan of the main shaft, with the
apparatus attached; while Fig. 11 shows a longitudinal section of Fig. 10.
A is the main shaft as before; a', a hollow casting fixed on the end thereof,
on the square part of which the eccentric b' is fitted and furnished with the
traversing screw c¹; on this screw is fitted the wheels or pinions 1 and 2 as
before, 1 having a screwed boss fitting c¹, the other 2 connected only by a
feather and groove; a pinion d' gearing with wheel 1 carries on its shaft the
hand wheel J', while the pinion e' gearing with wheel 2 has fixed on it
a notched plate f; this may be fixed by a bolt g fixed to part of the framing,
while the wheel J₁ may be fixed or loosened by a clutch piece ' on the axis
of d. This gear answers the purpose of traversing the eccentric to a greater
or lesser radius as before described by rotating the hand wheel in the same or
reverse direction as the motion of shaft A', during which time the hand wheel
is to be clutched to pinion d', and the pinion e¹ prevented rotating be
bolt g. In long runs the clutch and bolt g' are withdrawn so as to
allow the whole gear to run round with the shaft A', and so obviate wear of
the parts.
. It will be observed that dovetailed slides e, f, D, E, Figs. 1, 3, 6, and 7,
and the eccentrics in Figs. 4, 5, 8, 9, 10, and 11, are disposed out of the
radial or centre line in order to give the necessary lead and lap while working
in both directions, and for the proper action of the gear in working the steam
more or less expansively, as will be readily understood.
Having described the nature of our Invention, and the manner of per-
forming the same, we declare that what we claim as our Invention to be
protected by the herein-before in part recited Letters Patent is,-
First, the combination and arrangement of slide valves represented in the
Drawings, Fig. 2, hereunto annexed, applied as and for the purposes herein-
before described.
We also claim the use of movable plates inlaid in the slide face, and
operated by a small steam cylinder as a substitute for the double valve herein-
before described.
Secondly, we claim the application of the several arrangements of parts or
gear for operating the valves of steam engines as and for the purposes described,

page_text: and either by hand or self-acting by means of a governor, all as herein-before
described and represented in the Drawings annexed.
In witness whereof, I, the said Henry James Hogg King, for myself,
and on behalf of the said Hubert Ellis Smith and Joseph Bennett
Howell, have hereunto set my hand and seal, this Nineteenth day
of June, in the year of our Lord One thousand eight hundred and
sixty-five.
Witness,
W. CLARK,
Patent Agent,
53, Chancery Lane,
London.
HENRY JAMES HOGG KING. (L.S.)