IMPROVED MECHANISM FOR WORKING THE VALVES OF STEAM AND OTHER MOTIVE POWER ENGINES
Year: 1872

page_text: LETTERS PATENT to William Tighe Hamilton, of Rathmines, Dublin,
Ireland, Gentleman, for the Invention of "IMPROVED MECHANISM FOR
WORKING THE VALVES OF STEAM AND OTHER MOTIVE POWER ENGINES."
Sealed the 11th February 1873, and dated the 9th December 1872.
PROVISIONAL SPECIFICATION left by the said William Tighe
Hamilton at the Office of the Commissioners of Patents, with his
Petition, on the 9th December 1872.
I, WILLIAM TIGHE HAMILTON, of Rathmines, Dublin, Ireland, Gen-
tleman, do hereby declare the nature of the said Invention, for "Iм-
PROVED MECHANISM FOR WORKING THE VALVES OF STEAM AND OTHER MOTIVE
POWER ENGINES," to be as follows:-
The nature of my Invention is as follows:-On a shaft or axle I place
a wheel or pulley concentric with the axle, but so arranged that it can
be set at a more or less oblique angle on the shaft. I surround this
pulley with a ring similar to the hoop or ring of an excentric. To this
hoop or ring I attach rods, which therefore partake of the motion
imparted to the ring by the rotation of the axle and pulley. This motion
of the axle is partly reciprocatory and partly rotatory or swinging, and

page_text: the motion imparted to the rods I adapt to steam engines for the purpose
of actuating the slide valves so as to obtain expansion of the steam in the
cylinder, and to reverse the engine by regulating the travel and "cut-off"
of the slide valve. This object is effected by placing on the crank shaft
of the engine a pulley as described above, and so arranged and connected
with a clutch box or or pulley sliding on a feather on the shaft that
by moving the clutch pulley along the shaft to or fro the angle of
obliquity of the slide valve sheave (as it may be called) to the axis of
the crank shaft can be altered, neutralized, or reversed, as may be
required. To the hoop of the sheave I attach a second hoop, so that the
latter can swing on the former just as a compass swings in gimbals.
To this second ring I secure one or more arms, and to these arms I
connect the rod known at present as the excentric rod of the engine.
The action of the arrangement is as follows:-When starting the
engine in one direction the handle of the lever which actuates the
shifting clutch pulley is moved to the proper side. This sets the slide
valve sheave obliquely on the crank shaft, and moves the arms and
excentric rod and slide valve. The engine starts, and a fixed stud or
other equivalent device on the shaft encounters another fixed projection
on the slide valve sheave, and the slide valve sheave rotates with the
shaft. These fixed studs are so arranged and set as to provide the
desired amount of "lead" for the slide valve, and are so arranged as to
admit of altering the amount of lead at pleasure, either for forward or
for back gear. As the crank shaft rotates the slide valve sheave it (by
its oblique movement) actuates the arms on what I call the gimbal hoop
and thereby moves the slide valve. If full steam is required the
reversing handle is put to the extreme end of its travel, thus setting
the slide valve sheave at its greatest obliquity. If expansion is required
the reversing handle is moved so as to give a less degree of obliquity to
the sheave. If the engine is to be stopped the sheave is set true, and
then the slide valve simply remains at rest in the centre of its stroke, as
the slide valve sheave will rotate within the hoop without imparting any
movement to it. If the motion of the engine is to be reversed the
reversing handle (when pulled in the right direction) moves the sliding
pulley on the shaft and feather and sets the sheave at an angle more or
less oblique, and opposite to that it had at first. The engine shaft is
then (if necessary) turned by hand till the studs engage each other
when the engine will work in the required direction.

page_text: From the above description it will be seen that by this plan of a pulley
set obliquely on a shaft I can regulate the slide valve of steam or other
motive power engines, and perform with it all the functions at present
performed by the link motion and two excentrics with much less com-
plication of parts and in a less costly manner than can be secured with
the latter arrangement. In the ordinary link motion and excentric
(owing to the leads of the two excentric) the lead of the one has a
certain injurious effect on the action of the other, and no position at which
the link can be set will allow the slide valve to remain at perfect rest
while the crank is in motion, whereas in my plan no such disadvantages
exist, because as there is but the one sheave for the cylinder no disturbing
action can take place.
The plan of setting a pulley or sheave more or less obliquely on a
rotating shaft can be applied to any form of steam, air, or other gas
engine, or to engines moved by water power, or to any form of engine
requiring to bave certain apertures. opened and closed at certain
intervals.
I do not confine myself to the use of a single shcave, but may employ
more than one, and I sometimes employ and arrange more than one in
combination, using one to neutralize another, or to add to its action, as
may be necessary. I do not confine myself to the particular arrange-
ment described above for one sheave, as I can fit the sheave or sheaves
on an independent shaft driven from the cranked shaft by toothed gear
or other equivalent mechanical devices, and set the independent shaft at
an angle to the cranked or other shaft driving it.
A combined rotative and reciprocating motion can be obtained on one
and the same shaft by so arranging the hoop that it can move in any
direction except rotating with the sheave, and by restraining it from this
movement (by means of a rod attached to the ring and so secured to a
fixed piece as that this movement alone is prevented) I can produce the
effect that when the crank or other first motion shaft is rotated it will
(by the action of the obliquity of the sheave) move endways with a
reciprocatory motion proportionate to the angle of obliquity of the
sheave; or the shaft may be fixed by collars in this direction, and the
sheave be attached on a sleeve shaft, and made to slide on the main
shaft on a feather. I propose to employ all or any of these arrangements
or any combination of them to actuate the slide, plug, double beat

page_text: equilibrium, or any other form of valve or combination of valves
employed, to open and close the ports of steam or other gas or water
engines.
SPECIFICATION in pursuance: of the conditions of the Letters Patent,
filed by the said William Tighe Hamilton in the Great Seal
Patent Office on the 9th June 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
TIGHE HAMILTON, of Rathmines, Dublin, Ireland, Gentleman, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of December, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Tighe Hamilton, Her special
licence that I, the said William Tighe Hamilton, my executors, ad-
ministrators, and assigns, or such others as I, the said William Tighe
Hamilton, my 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
"IMPROVED MECHANISM FOR WORKING THE VALVES OF STEAM AND OTHER MOTIVE
POWER ENGINES," upon the condition (amongst others) that I, the said
William Tighe Hamilton, my executors or administrators, by an instru-
ment in writing under my, 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 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 I, the said William Tighe Hamilton, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference, being had to the Drawing

page_text: hereunto annexed and to the letters and figures marked thereon (that is
to say) :-
This improved mechanism for working the valves of steam and other
motive-power engines relates to the particular application of the general.
principle of the reciprocator for which I obtained Letters Patent, dated
the sixth day of December One thousand eight hundred and seventy-
two, No. 3704, to the purpose above mentioned. The improved
reciprocator, described in the Specification of the Patent above referred
to, consists in its general or fundamental form of a circular grooved
pulley, disc, or sheave, mounted upon a rotating axle, and provided with
a strap revolving in the groove and a short rod fixed into the strap at the
middle of its width in line through the central line of the axle. Its
component parts thus far resemble the sheave, the strap, and a portion
of the rod of an ordinary excentric. But in the reciprocator the sheave
is concentric with the axle and is placed at an angle of inclination (not
at right angles) to the direction of the latter. The motion of the rod when.
the sheave and axle rotate will thus be parallel to the direction of the axle,
not transversely to it. And the object of the present Invention is to
utilize this motion or other motions derivable from the same for working
the valves of steam or other motive-power engines.
The general nature of this construction will be seen in Figures 6
and 7 in the accompanying Drawings, and hereafter more particularly
referred to. In these Figures the parts appear in their simplest form, Z
being the strap, R the rod, and O an oblique hole in the sheave, through
which the shaft of the engine passes. It will be obvious that if the rod O
be free to move in the vertical stud V which is carried by a bell .crank
connected with the slide rod, this rod will travel backwards and forwards
with a throw proportioned to the angle of inclination of the sheave on-
the axle, and the distance of the stud from the axle, and the same or
any other extent of travel will be'communicated to the valve slide.
through the medium of the bell crank A, A, according to the length of
its arm.
This rod may be called the throw rod, and so far the travel
derived from it will be the same in kind as that imparted to the valve
slide by an ordinary excentric, that is, it will always be the same in
extent and..direction.. In order however to render the motion or travel
of the valve. variable in both these respects, so as to regulate the supply
of steam and, the reversal of the engine, a further provision must be
made, as shewn at Fig. 3, hereafter more particularly described. The
'
Г
b

page_text: strap must be surrounded by a circular hoop so mounted by means of
gimbals (or trunnions) that the two parts may swivel upon each other
as in the mariner's compass. This hoop is shewn at H in Fig. 3, and
the throw rod S must now be taken as fitted into this hoop instead of
into the strap as before, and in line through the gimbals G, G. If then t
this hoop be kept in a vertical position by means of the pin P at the
extremity of a cross diameter, and it be free to twist in a hole in the bed
plate, the hoop will swing to and fro in vertical planes, and every point
in the circumference of the hoop will have a different extent of throw.
This throw will be greatest at the extremities of a horizontal diameter,
and it will cease at those of a vertical diameter. The intermediate points
will have a throw proportioned to their angular distance from a vertical
diameter. This hoop may be called the gimbal hoop.
The manner in which these variable throws can be utilized will be
explained hereafter. For the present moment explanation is only.
necessary as to the two extreme points. With respect to these it is
obvious that, as the hoop swings to and fro the extremities of its vertical
diameter will be dead points, or rather centres of motion, and that if
lever arms be attached at that point above and below, parallel to the axle,
these arms will swing to and fro, so that their outer extremities will
become fit points of attachment for the forked slide rod, as shewn at
Fig. 3. A connection can thus be made between the slide rod and either
the throw rod or the above-mentioned lever arms, according as may best
suit the different particular forms which may be adopted for the general
mechanism. These may be ranged under four different heads of
form.
"
I. The First Form is where the sheave (as shewn in Figures 1 and 2) is
mounted upon a square sleeve shaft 8, 8, so as to swivel upon it by
means of pivots g, g, and this sleeve shaft is then kept in position on the
crank shaft o of the engine by collars or other means required for the
purposes of "lead," as hereafter to be explained. On one of the flat sides
of this sleeve shaft (not being one of those into which the pivots enter)
a plate p, p, which is connected with an ordinary clutch box O is free to
slide backwards and forwards. When the clutch box is so moved upon
the crank shaft a screw Q with a spherical end passes through the
sheave into a cylindrical hole T in this plate, and thus the sheave can be
turned on the pivots, and kept at any desired angle of inclination to the
shaft by means of an ordinary finger F worked by a lever or other con-

page_text: venient appliance. When the lever is put to its extreme position on
one side the travel of the slide rod, whether connected with the throw
rods or with the lever arm, will be at its extreme extent, and when at
such position the travel will cease; when at its extreme positions on
the other side its direction will be reversed. In all intermediate
positions its direction and extent will correspond with the position of the
lever handle. The engine can thus be regulated both as to expansion
and reversal.
II. Second Form.-The sleeve (as shewn in Figures 3, 4, and 5) is
placed direct on the crank shaft without the intervention of a sleeve
shaft, but at a constant angle of inclination, that is, the shaft O
through the sheave is bored obliquely at that angle. If therefore the
arms A, A', be placed across the hoop above and below parallel to the
shaft, and at right angles to the plane of the hoop, they will swing to
and fro across the shaft, and the motion of that portion of each which
is on one side of the hoop will be contrary to that of the portion on the
other side. These arms have slotted ways m, m, running along their
central lines, the centre of the slotted ways being over the centres of
motion above and below. The forked extremities of the slide K, K, are
provided with studs or pins which turn or traverse in these slotted ways,
or the rod itself is carried from one end to the other by a screw or lever,
or other suitable appliance. The travel of the slide valve will thus be
varied, stopped, or reversed, as required. The appliance by which this
traversing movement of the slide rod may be effected consists of a small
frame B, Fig. 5, carrying a screw with a handle and a round spindle ƒ³.
Upon this screw and spindle a small carriage n, n, travels, in which a
vertical stud V is mounted. The slide rod is made to pass through a
suitable hole in this stud, and is thus kept in proper position relatively.
to the slotted arms, whilst it is free to slide in the stud to the required
extent of end movement or travel. The action of the screw carries it
from end to end of this small frame, and keeps it in its desired position.
III. In the Third Form the gimbal hoop may be dispensed with, and the
reciprocator may be used in the simple form shewn in Figs. 6, 6 * and 7.
Here instead of two slotted arms being mounted above and below the
centres of motion a single slotted arm A, A, is mounted upon the bell
crank over its centre of motion, so as to be free to turn in a socket
hole M in the pillar N. The slide rod is made to traverse in the slotted
way d, d, above this arm in the same manner and by the same appliance

page_text: 4
as before and with the same effects. In both this and the preceding
form however the above appliance for the traversing motion may be
dispensed with, and the end of the slide rod may be moved by hand and
fixed at any suitable part of the slotted way by means of a clamping
screw.
I would observe that in each of the three preceding forms, when it is
desired to provide for the reversal of the engine, it will be necessary
also to provide for the proper amount of "lead" for the slide valve.
For this purpose the above mentioned sleeve shaft or the above sheave,
as the caso may be, is free to turn upon the crank shaft until a fixed pin
or stud or other equivalent device attached to it encounters a corre-
sponding obstacle on the shaft. These pins or studs are so arranged and
set as to provide the desired amount of lead and admit of altering this
amount at pleasure either for forward or back travel. This arrangement
is not shewn in the Drawings as it is a device already in frequent use.
IV. The Fourth Form (as shewn in Figures 8 and 9) requires no pro-
vision as to "lead," as it is only designed for variable, not reversing
motions. The sheave can therefore be at once keyed upon the shaft at
its proper inclination and at the proper degree of advance for the purpose
of "lead."
It has been already shewn that when the gimbal diameter is main-
tained in a vertical position every point in the circumference of the
guide hoop will have its throw proportioned to its angular distance from
that diameter. The same law. exists when the gimbal diameter is placed
in any other than a vertical position, and if we conceive the gimbal hoop
as consisting of two parallel hoops, one carrying the throw rod and the
other the gimbal, it will be obvious that as the gimbal diameter and
gimbal hoop are carried round from the vertical to the horizontal position
the throw rod and parallel hoops will be left behind, and the throw rod
will have a travel proportioned to its angular distance from the gimbal
diameter, that is, it will have the throw corresponding to that point in
the gimbal hoop which coincides with it in its then position. The
movement of this gimbal diameter will thus impart every extent of
motion from the fullest extent when it is vertical to a cessation of all
motion when it is horizontal. This arrangement is shewn in Figures 8
and 9, where the parallel hoop H' is. attached to the gimbal hoop by
screws working in slots so as to be free to move on it through one

page_text: quadrant or quarter of a circle. A cranked lug L passes from it across
both hoops and carries the throw rod R at the middle point of the
gimbal hoop, whilst the gimbal hoop itself carries the pin P. This may
be called the guide pin. This form does not admit of a connection by
means of lever arms with the slide rod S, as in the two first of the other
forms, because in certain positions the gimbal hoop has a twisting motion
relatively to it. The appropriate connection is by means of a bell
crank C and stud V, where the throw rod can twist on the stud.
"
Various means of carrying the gimbal diameter through different
angles of inclination (but always in the same plane) may be adopted.
For example, the guide pin P may work in any suitable carriage or
appliance, which is provided with a hole in which it can twist; and
this carriage can be moved either by a lever or sector or suitable gearing
from P to P¹¹¹, or it may be connected with the governor and so become
self-adjusting, according to the requirements of the engine in respect to
supply and expansion.
When the guide pin is at P the slide rod will impart the greatest
extent of travel, whilst when it is at pu the travel will cease and the
valve slide be at perfect rest.
For any of these arrangements of valve mechanism the construction
of the reciprocator may be varied by using any other of its equivalent
forms than that above described. Thus instead of the sheave a hub or
boss with an oblique concentric hole through it for the shaft may be
used. The strap will revolve upon it when kept in motion by two
suitable plates fixed to the strap and working against the end of the
hub or boss.
•
Another form of reciprocator may be used, which consists of a strap
revolving upon a portion of the shaft, which is cranked at an angle of
inclination to it so as to form an angular cranked pin. In such case
the cranked portion takes the plane of the sheave or boss, the rest of
the construction remaining the same as before. If it should be required
to reverse the engine the cranked portion forming part of the recipro-
cator should be a separate piece introduced into a hole in the end of
the shaft, so as to be free to turn and adjust itself to the required
position in advance of the engine crank for the purposes of "lead" as
already described. In this case the mechanism will be placed outside,
not inside, the bearings of the shaft.

page_text: I would remark that I propose to perform with certain of the above
arrangements all the functions now performed by what is known as the
link motion, but without its two main defects, namely, the injury which
the "lead" of the one excentric produces on that of the other, and the
absence of perfect rest, which in that case can exist at no time when
the crank shaft is in motion, whilst in this case the use of but a single
sheave or its equivalent admits of no such disturbing influence.
Having now described my Invention of "Improved Mechanism for
Working the Valves of Steam and other Motive-power Engines," and
having explained the manner of carrying the same into effect, I claim
as the Invention secured to me by Letters Patent as aforesaid the use
or application of any of the above described or other equivalent forms of
an inclined pulley, sheave, boss, or angular crank to the shaft or axle of
a motive-power engine for the purpose of producing constant or variable
degrees of motion or travel or different, direction of motion or travel in
the valves of such motive-power engines.
In witness whereof, I, the said William Tighe Hamilton, have
hereunto set my hand and seal, the Ninth day of June, in the
year of our Lord One thousand eight hundred and seventy-