ROVEMENTS IN AND APPLICABLE TO VALVES FOR RECIPROCATING ENGINES DRIVEN BY STEAM OR OTHER ELASTIC FLUID
Year: 1853

page_text: place, Engineer, for the Invention
MPROVEMENTS IN AND
APPLICABLE TO VALVES FOR RECIPROCATING ENGINES DRIVEN BY STEAM
OR OTHER ELASTIC FLUID."
Sealed the 22nd February 1854, and dated the 14th September 1858.
PROVISIONAL SPECIFICATION left by the said John Wakefield
at the Office of the Commissioners of Patents, with his Petition,
on the 14th September 1853.
WC, JOHN WAKEFIELD, of Inchicore Works, in the County of Dublin,
Engineer, and JAMES BASKERVILLE, of the same place, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
AND APPLICABLE TO VALVES FOR RECIPROCATING ENGINES DRIVEN BY STEAM
OR OTHER ELASTIC FLUID" to be as follows:-
Our Invention consists in substituting for the ordinary slide valve
gear for reversing and expansive action in steam engines one excentric
sheave or wheel and strap, by means of which may be obtained such
double action as is suitable for the correct working of the two slide

page_text: valves, either for forward or backward motion of the engine, and at the
same time with various degrees of expansion of the steam. The
excentric consists of two portions, one of which is a rectangular plate
of wrought or cast iron or other metal keyed or otherwise fixed on to the
crank shaft, and the other a circular ring so contrived by means of
suitable guides or slides attached to it as to slide in the required
manner upon the face of the fixed plate, and this plate is fixed in such
a position on the shaft as that the ring may be moved or slidden upon
it in a direction at right angles to one of the cranks (or one arm of the
crank), and parallel to the other. Over this ring is passed the strap
through which the motion is given to the valves, and from it the
excentric rod proceeds to one of the valves, viz., that belonging to the
crank which is at right angles to the direction in which the circular
ring slides upon the fixed plate. And this ring is to be put into
permanent connection with the reversing lever or wheel (convenient to
the hand of the engine man) by means of certain rods, levers, screws,
&c. By this means the ring may be slidden into the required positions
either for forward or backward action of the valves, and also into
intermediate positions, so as to cause the valve to which its red is
attached to cut off the steam at various points in the stroke of the
piston, thereby giving considerable range of expansive action during
either movement.
A motion exactly similar to what is thus imparted to the valve
above referred to is communicated to the other valve by means of
a contrivance which we call a right-angled lever placed loose upon
the crank shaft so as to allow the shaft to revolve without carrying
it round. This right-angled lever is placed alongside and close to the
excentric ring, and one of its arms is in the horizontal position (either
"before" or "behind" the crank shaft), and the other is in the vertical
position (either up or down), according to circumstances. The horizon-
tal arm has near its end a pin, or the arm itself is bent so as to project
into a slot or groove made in a projection upon either the fore or back
half of the exentric strap, and this slot or groove must be made exactly
the centre line of the excentric rod.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Wakefield in the Great Seal Patent Office
on the 14th March 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we,
JOHN WAKEFIELD, of Inchicore Works, in the County of Dublin,
Engineer, and JAMES BASKERVILLE, of the same place, Engineer, send
greeting.
:
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of September, in the
year of our Lord One thousand eight hundred and fifty-three, in the
seventeenth year of Her reign; did, for Herself, Her heirs and suc-
cessors, give and grant unto us, the said John Wakefield and James.
Baskerville, Her special license that we, the said John Wakefield
and James Baskerville, our executors, administrators, and assigns, or
such others as we, the said John Wakefield and James Baskerville,
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 migh make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN AND APPLICABLE TO VALVES FOR RECIPROCATING ENGINES
DRIVEN BY STEAM OR OTHER ELASTIC FLUID," upon the condition (amongst
others) that we, the said John Wakefield and James Baskerville, by an.
instrument in writing under our hands and seals, or under the hand and
seal of one of us, 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 John Wakefield and James
Baskerville, 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, reference being
had to the Drawings hereunto annexed, and to the letters and figures
marked thereon, that is to say:

page_text: Our Invention of " Improvements in and applicable to Valves for
Reciprocating Engines driven by Steam or other Elastic Fluid" has
reference to the mode of working the slide valves of engines, the
cylinders and cranks of which are variously arranged and constructed,
and consists in substituting for the ordinary slide valve gear the me-
chanism herein-after described, by means of which the valves
may be
suitably worked in order to produce either the forward or backward
motion of the engine, as required, and also to cut off the supply of
steam at any required point of the stroke of the pistons, so as to
regulate the degree of its expansive force and its consumption in the
cylinder or cylinders.
The mechanism for this purpose consists essentially of one excentric
sheave or wheel composed of two principal parts distinct from each
other, one portion being fixed on the crank shaft, and the other move-
able upon the said fixed portion or guide, and being capable of being
set in its required position thereon through the ordinary hand gear
and suitable intermediate mechanism so as to work the valves through
their requisite movements. In double cylinder engines with the cranks
at right angles to each other, the valve immediately acted upon by the
excentric would be that in connection with the crank at right angles to
the direction of motion of the said moveable portion through the
agency of an excentric ring forming part thereof or attached thereto
(in its suitable relative position) and the ordinary strap and rod leading
to the valve. Then the motion required for the other valve (or that
connected with the crank at right angles to that before mentioned)
is imparted thereto by means of a contrivance which we call a right-
angled lever, placed loose upon the crank shaft, or so placed upon any
other point distinct from the crank shaft as to enable the right angled
lever to receive the required motion from the excentric sheave, and
acted upon in one of its arms by a projecting piece connected to the
said excentric strap, the motion being communicated from the other
arm of the lever to the valve through the agency of a rod.
The moveable portion of the sheave with the excentric ring may be
slidden over the face of the fixed portion or guide (by the means
herein-after described) so as to be in a suitable position to control and

page_text: regulate the action of the valves; whether for. forward or backward
motion of the engine, or for cutting, off the supply of steam at the re-
quired interval.
In order, however, that our Invention may be fully understood,
and readily carried into effect, we will proceed to describe it more
particularly by the aid of the accompanying Drawings, in the several
Figures of which the same letters of reference indicate corresponding
parts.
The following description refers to our Invention as adapted to double
cylinder engines, the cylinders of which are parallel, and the cranks at
right angles to each other; but our Invention is not confined to engines
of this form and construction, as will be herein-after more particularly
stated.
2
Fig. 1, is a plan or horizontal view of the mechanism referred to;
Fig. 2, is an elevation; Fig. 3, a horizontal section; and Fig. 4, a ver-
tical section of the same in the line Y, Z, of Fig. 3; Figs. 5, to 16
represent different parts of the mechanism detached.
$
A, is the ordinary crank shaft with the two cranks B, and C, at
right angles to each other. D, is the fixed rectangular driving guide on
which the moveable portion D*, of the sheave may be slidden. The
guide D, is firmly fixed to the shaft A, with its guide faces or edges
parallel to the crank B, and at right angles to the crank C. On éach
side of this driving guide D, (shewn detached at Figures 7, and 8;) is
a projection containing an internal space e, within which a nut E, is
capable of turning. These nuts are in the form of pinions on their
outer circumference, and have screw threads cut upon their internal
surface, so as to be capable of transmitting motion received from the
racks F, to the right and left handed screws G, the ends of which are
fixed by cotters and nuts to the moveable portion .D*, of the sheave.
By this means, when the nuts E, are turned by the movement of the
racks F, the effect is to project the screws G, outwards, and with them
the moveable piece D*, in either direction, according as the nuts are
turned to the right hand or to the left. Attached to this moveable
piece D (or forming part of it) is an excentric ring I, which by such
connection may be moved into positions suitable for forward or back-

page_text: ward motion of the engine, and also into positions adapted for working
-the valves, so as to cut off the steam at the required interval, and
thereby leave it to act expansively during the remainder of the courses
of the pistons within their cylinders. This excentric ring is fixed to
the sliding piece D, or formed so as to be capable of acting in such a
position with respect to the crank C, as to be suitable for the intended
amount of "lap and lead" of the valves.
In Figures 3, and 4, this excentric ring I, is shewn in its position
suitable for a full throw forward action, and its centre is at 9, Fig. 4.
In the other extreme position (or that for a full throw backward
.action) its centre would be at 11, and its centre in its middle position
would be at 10. The distance between the point 9 and the centre of
the crank shaft indicates the distance required to give the suitable
lap and lead" to the valves. When the centre of the ring 1, is
-brought into any intermediate position between the points 9 and 11,
the valves are made to act "expansively," or so as to cut off the steam
at a certain interval, and allow it to work merely by its expansion
during the remainder of the stroke of the piston. The steam is so cut
off, either earlier or later, according as the centre of the ring I, is moved
into a position either nearer to or farther from the point 10, every
position between the points 10, and 9, being suitable for forward action,
and the same between 10, and 11, answering for backward action.
By this means it will be seen that the required working of the valves
is under control and regulation through the excentric ring I, being
placed in its suitable position on the fixed guide D; and it remains only
therefore to describe the means by which the ring may be shifted to its
required position, and also that by which it may be made to act suitably
upon the valves from such position.
The racks F, receive motion from the clutch J, shewn detached at
Figs. 5, and 6, and in its relative position with the other parts of the
mechanism at Figs. 1, and 3. On reference to Fig. 3, it will be seen
that one end of each rack is made fast to the clutch J, also that this
clutch has a groove formed on its circumference into which is let
the strap K. This strap has parallel grooves formed on its two opposite
sides, in which grooves the blocks M, may slide easily. These blocks

page_text: are connected by pin joints to the two levers I, one on each side of the
strap K, which levers are fixed to the reversing shaft N, which may
be acted upon by the lever O, conveniently placed for use by the engine
man. The precise position of this shaft, and the means of acting upon
it, may be varied in different engines, but the object of the arrangement
is to enable the attendant, by moving the lever O up or own, (or by
acting upon the shaft N, in a similar manner by other means,) to cause
the clutch J, to slide along the crank shaft A, the effect of which will
be that the pinion nuts E will be turned by the rack F, and the
screws G made to slide the moveable piece D, and ring I, over the
faces of the fixed guide D. In this manner the ring I, may be placed
in its required position by acting upon the lever O. The clutch J,
revolves with the crank shaft A, but the strap K does not turn with
it, and the parallel grooves on its opposite sides are always in contact
with the ends of the levers L, and blocks M. The object of such
grooves is to allow for the requisite degree of compensation for any
limited amount of vertical motion likely to be imparted to the levers L,
and not participated in by the crank shaft. This would be more
especially requisite in the case of locomotive engines.
The valves are worked from the excentric ring I, by the following
means-P, is a metal strap, which is put upon the excentric ring I.
On this excentric strap (shewn detached at Figs. 11, and 12,) is a
projection P', (either on its front or back part, or upon any other part
of the circumference of the strap P,) having cut in it a slot or groove p,
opposite to or parallel with the excentric rod P, which rod is carried
or the slot may be made
direct to the valve in connection with the crank C, A in the excentric
rod P. On the back part of the driving guide D, is formed a circular
groove (see Fig. 3,) into which is let a right-angled or bell-crank
lever Q, seen in Figs. 1, 2, and 3, and shewn detached at Figs. 13,
and 14. This lever fits the groove loosely, so as to allow the driving
guide D, to turn with the crank shaft A, without turning the lever.
One arm Q', of this right-angled lever is in the horizontal position;
and the other Q2, is in the vertical, either above or below, as circum-
stances require.

page_text: be bent as shewn, which pin or which bent end of the arm is intended
to project into the slot p, in the projection P¹, of the excentric strap,
and form a connection between such projection and the arm of the
lever; a block p*, of a suitable size to slide loosely in the groove p,
being placed on the end of such pin or arm which is made round to
receive it. By this means the vertical motion of the excentric sheave
or ring will become imparted to the horizontal arm Q', of the right-
angled lever, whence it will be transmitted in a horizontal or nearly
horizontal direction by the vertical arm Q³, through the rod R, (see
Figs. 1, and 2,) to the valve in connection with the crank B.
Hence it will be seen that the whole action of the above-described
valve gear is as follows:-Assuming the parts to be in the position
shewn in the Drawing, viz., with the excentric ring I, in the position
on the driving guide D, required for working the valves with the full
throw forward action, then, as the crank shaft A, revolves, it will carry
with it the excentric sheave or wheel (composed of the parts D, D", and
I), and a reciprocating motion will be communicated by the excentric
ring I, through the strap P, and rod P2, to the valve in connection
with the crank C, thereby producing an action of the valve which
would cause the required admission of steam. And the suitable action
of the other valve, or that in connection with the crank B, is caused by
the motion of the right-angled or bell-crank lever Q, received in its
arm Q', from the projection P', of the strap P, and transferred by its
arm Q2, through the rod R, to the valve.
When the engine is required to be reversed for the full throw back-
ward action the excentric ring I, must be moved on the face of the
fixed guide D, so as to occupy the position indicated by the point 11,
(Fig. 4,) for its centre. The lever O, must be moved the suitable
distance (which may be determined in any convenient manner) so as to
turn the reversing shaft N, and thereby act upon the clutch J, through
the levers L, so as to move the clutch towards the crank C. By this
motion of the clutch, carrying with it the racks F, the pinion nuts E
will be turned, and the right and left handed screws G made to draw
the sliding piece D*, outwards on the face of the fixed guide D, until
the excentric ring I, is made to occupy its required position on the

page_text: guide, that is to say, until the sliding piece D, with the excentric
ring I has been moved from its position indicated at 1 and 2, at
Fig. 4, to that indicated by 3 and 4, in the same Figure. The
movement of these parts is suitably compensated or assisted by the
counterbalancing weight T, on the projection S of the lever Q, Fig. 3.
The consequence of thus altering the position of the excentric ring I,
is, that the rod P, having its position correspondingly altered, but.
allowing the "lead" of its valve to remain the same as before, and the
rod Q, from its connection with the projection P¹, of the strap P,
being moved to the opposite side of the crank B, and through the
rod R, carrying its valve with it, the action of the engine will become
reversed. And when it is required to work the valves "expansively"
the excentric ring must be moved by the means described so that its
centre may occupy an intermediate position between 10 and 9,
(Fig. 4,) for the forward action of the engine, and between 10 and 11
(Fig. 4,) for the backward action, the period at which the steam is cut
off depending upon the exact position of the centre of the excentric
ring within such limits respectively.
It may be here remarked that although we have described the
means of carrying our Invention into effect by a reference to its
application to engines with double cylinders parallel, and the cranks at
right angles to each other, yet the application of our Invention is not
confined to such engines. It may also be adapted and applied to
double cylinder engines with the cylinders at right angles to each
other, and the power applied to one crank; also to single cylinder
engines, whether they reverse or not; also to engines with oscillating
cylinders, and whether condensing or non-condensing; also to engines
with the cylinders either in a vertical, horizontal, or oblique position,
and with various modes of construction of the cranks.
It may be further remarked that in some cases it may be desirable
to use a second excentric sheave, or wheel composed as described, and
with its appurtenances of racks, pinion-nuts, and screws, instead of the
right-angled or bell-crank lever, to act upon the second valve. In such
case the clutch would be placed between the two excentrics, and each
pair of racks at right angles to their respective crank.

page_text: Having thus described the nature of our Invention, and in what
manner the same is to be performed, we would have it understood that
we not mean or intend to cenfine ourselves to the exact forms or details
of the parts shewn and described, neither do we claim any of the well-
known parts to which it has been necessary to refer in describing our
Invention. But what we do claim as of our Invention is, the substitution
for the ordinary means of suitably working the slide valves of engines of
a single excentric sheave or wheel composed of one portion fixed to the
crank shaft, and another moveable over such portion, the latter being
capable of suitably working the valves (according to the position in
which it is placed) through a strap and rod, as described.
In witness whercof, we, the said John Wakefield and James
Baskerville, have hereunto set our hands and seals, this Eighth
day of March, One thousand eight hundred and fifty-four.
JAMES
BASKERVILLE. (L.S.)
Signed, sealed, and delivered in the presence of,
the words "or the slot may be made,"
being first interlined between the twenty-
seventh and twenty-eighth lines of the
third page [twenty-sixth line of the seventh
page hereof,
JOHN NETTLETON, 5, Malpas Street, Dublin.