IMPROVEMENTS IN MACHINERY FOR WORKING THE SLIDES AND STRAK VALVES OF ENGINES DRIVEN BY STRAK OR OTHER ELASTIC FLUID
Year: 1855

page_text: LETTERS PATENT to John Wakefield, of Inchicore Works, in the County
of Dublin, Engineer, for the Invention of "IMPROVEMENTS IN MACHINERY
FOR WORKING THE SLIDES AND STRAK VALVES OF ENGINES DRIVEN BY STRAK
OR OTHER ELASTIC FLUID."
Sealed the 29th April 1856, and dated the 7th November 1855.
PROVISIONAL SPECIFICATION left by the said John Wakefield at the
Office of the Commissioners of Patents, with his Petition, on the 7th
November 1855.
I, JOHN WAKEFIELD, of Inchicore Works, in the County of Dublin,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE
MENTS IN MACHINERY FOR WORKING THE SLIDES AND STEAK VALVES OF ENGINES
DRIVEN BY STEAM OR OTHER ELASTIC FLUID" to be as follows:-
My Invention consists in working the slides and steam valves of engines in
forward, backward, or expansive action, as may be required, by means of an
excentric sheave or excentric sheaves, having a series of inclined teeth on their
inner surface, with suitable sliding guides working on or over the driving guides,
forged or fixed on the crank shaft, combined with sliding racks, with a series
of inclined teeth on each, acting upon the corresponding teeth on the inner
surface of the excentric sheave, and passing through the driving guide; the
racks being also connected to a clutch on the shaft (similar to the arrangement
described in a Patent granted to me and James Baskerville, and bearing date

page_text: September 14th, 1853), such racks and clutch being slidden along the shaft
as required by means of the reversing lever. By this motion of the lever
the excentric sheave and sliding guides are slidden over the driving guides
to the respective positions for regulating the action of the valves by means of
the excentric strap and rods.
Another action exactly similar to that above described is communicated to
another valve by means of a bell-crank lever and rods, similar to the arrange-
ment described in the Patent above referred to. The sliding rack motion
may also be combined with two or more excentrics for acting upon the valves
respectively instead of an excentric and a bell-crank lever.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Wakefield in the Great Seal Patent Office on the
5th May 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
WAKEFIELD, of Inchicore Works, in the County of Dublin, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by IIer Letters
Patent, bearing date the Seventh day of November, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Wakefield, Her special license that I, the said John
Wakefield, my executors, administrators, and assigns, or such others as I, the
said John Wakefield, 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 "IMPROVEMENTS IN
MACHINERY FOR WORKING THE SLIDES AND STEAM VALVES OF ENGINES DRIVEN BY
STEAM OR OTHER ELASTIC FLUID," upon the condition (amongst others) that I,
the said John Wakefield, by an instrument in writing under my hand and
seal, should particularly describe and ascertain the nature of the said Inven-
tion, 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 John Wakefield, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,

page_text: 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):-
My Invention of "Improvements in Machinery for Working the Slides and
Steam Valves of Engines driven by Steam or other Elastic Fluid" has for its
object the substitution of the machinery herein-after described for the ordinary
slide and steam valve gear, and consists in working the slides and steam valves
of engines in forward, backward, or expansive action, as may be required, by
means of an excentric sheave or excentric sheaves, having a series of inclined
teeth on their inner surface, with suitable sliding guides working on or over
the driving guides, forged or fixed on the crank shaft combined with sliding
racks, with a series of inclined teeth on each, acting on the corresponding
teeth on the inner surface of the excentric sheave, and passing through the
driving guide; the racks being also connected to a clutch on the shaft, such
racks and clutch being slidden along the shaft as required by means of the
reversing lever. By this motion of the lever the excentric sheave and sliding
guides are slidden over the driving guides to the respective positions for
regulating the action of the valves by means of the excentric strap and rods.
Another action exactly similar to that above described is communicated to
another valve by means of a bell-crank lever and rods. The sliding rack
motion may also be combined with two or more excentrics for acting upon the
valves respectively instead of an excentric and a bell-crank lever.
In order, however, that my Invention may be fully understood and readily
carried into effect, I will proceed to describe it more particularly by the aid
of the accompanying Drawings, in which it is represented in various modes of
adaptation and application; but my Invention is not confined to engines of this
form and construction, but is applicable to locomotives, stationary, marine,.and
agricultural engines, either with one or more cylinders combined, and variously
arranged and constructed.
Fig. 1 is a side elevation, and Fig. 2 a plan or horizontal view, shewing an
adaptation and application of the Invention for working two valves with one
excentric sheave; Fig. 3 is a plan or horizontal view of a crank shaft with two
excentric sheaves, composed as herein-after described, each excentric sheave
having a strap and rod leading to their respective valves; Fig. 4 is a side
elevation, and Fig. 5 a plan or horizontal view, of an adaptation and application
of the Invention to an engine in which the cylinders and valves at placed at
right angles to each other, and the two valves are worked with one excentric
sheave, composed as herein-after described, and having two excentric rods at
right angles to each other leading to the two valves respectively; Figs. 6 to

page_text: 17 represent, detached, different parts of the mechanism for working the valves
according to my Invention; Fig. 18 is a side elevation, and Fig. 19 a plan or
horizontal view, of an adaptation and application of my Invention to work two
valves by means of two excentric sheaves combined with one pair of racks, the
racks acting on only one of such excentric sheaves; Figs. 20 and 21 represent
these two excentric sheaves in elevation. In all these Figures the same letters
of reference indicate corresponding parts.
A is the crank or driving shaft; B and C, the two cranks, at right angles to
each other; D, D, the double driving guides, forged or fixed on the shaft (shewn
detached at Figs. 6, 7, and 8), on and between the flanges of which the double
sliding guides E, E, on each side of the excentric sheave I may be slidden.
These sliding guides aro shewn detached at Figs. 9, 10, and 11, in which are
represented the excentric I with the sliding guides, having a series of inclined
teeth E formed on their inner surfaces. F, F, are two racks, which are placed
on the axle at right angles to the sliding guides E. These racks are curved
at the back to fit the curvature of the axle, and each rack has a series of
inclined teeth, corresponding with the spaces G between the inclined teeth on
the inner surface of the sliding guides E, E, to which it is applied, so as to
admit of the teeth of the rack working in the teeth of the guides. The racks
F, F, also pass through the fixed double driving guides D, D, and the con-
centric sheave V; one of them is shown detached at Figs. 12 and 13. These
racks F, F, are attached at one of their ends to the clutch J, which has a
groove formed in its circumference in order to receive the strap K. This strap
has parallel grooves on its two opposite sides, in which grooves the blocks M
may slide easily. These blocks are connected by bolts or pins to the levers L,
one on each side of the strap K, which levers are made on or fixed to the
reversing shaft N, which may be acted upon by the lever O, and intermediate
mechanism conveniently placed for use by the engineer. 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 engineer, by moving the
lever O up or down, or by acting upon the shaft N in a similar manner by other
means, to cause the clutch J, and racks F, F, connected thereto, to slide along
the shaft A, so that the teeth of the racks, by acting on the corresponding teeth
on the inner surfaces of tho excentric sheave and double sliding guides E, E,
on the excentric sheave I, may cause the sliding guides E, E, with the excentric
sheave I, to slide on the fixed double driving guides D to the position required
for working the valves. This position will be understood on reference to Fig. 1,
in which 1 shews the position of the centre of the excentric I for the full for-
ward action; 2 shews the same for the full backward action; 3 shews the

page_text: same for the middle or ordinary action, allowance being made for the lap and
lead of the valves, and at all intermediate positions between the points 1 and 2
the valves will be made to work expansively, or so as to cut off the steam at
certain intervals, and allow it to work merely by its expansion during the
remainder of the stroke of the piston; then the valves are worked from the
excentric sheave I by the following means:-P is a metal strap, which is made
to enclose the excentric sheave I; P* is the excentric rod connected to the
valve spindle Z, and thereby to the valve Z. At the junction of the strap and
rod is formed a slot T, within which a slide block T✶ is capable of sliding easily.
On any part of the circumference of the strap P a balance lever H is applied,
which lever is connected to the strap P by a link Y, and suspended from
brackets at X. The lever has on its end a balance weight U. This balance -
lever is represented detached at Figs. 16 and 17. From the connection shewn
in the Drawing between the strap and rod and the arm Q** of the right-angled
or bell-crank lever Q, (shewn detached at Figs. 14 and 15,) motion is com-
municated to this lever, and imparted therefrom through its arm Q to the
valve Z, through the rod R, and vavle spindle Z. The lever Q fits loosely on
the circular groove V, so as to allow the axle and circular groove to turn with-
out turning the bell-crank lever; or the latter may be placed in any other
convenient position, so as to be capable of receiving motion through its arm Q**
from the strap and rod P and P*. Hence it will be seen that by working the
starting lever O, the sliding guides E, E, and the excentric sheave I may be
moved into their suitable positions on the driving guides D for working the
valves as required by means of the mechanism above described.
Fig. 3 represents another mode of applying my Invention, and shews the
axle A with double driving guides D, and two excentric sheaves I, each
baving double sliding guides E, E, on each side, and in a position suitable
for the cranks at right angles to each other. These sliding guides E, E, and
excentric sheave I have a series of inclined teeth on their inner surface,
and there are two racks F, F, to each excentric sheave I, with teeth adapted
to work in those on their sliding guides. One end of each pair of racks is
connected to the clutch J on the axle between the two excentric sheaves I, I.
The motion is communicated to the valves through a strap P and rod P*
applied to each sheave. The starting lever O is worked in the same manner
as above described for the purpose of moving the sliding guides E, E, with
their excentrics I, I, into the positions respectively required for the forward or
backward or intermediate expansive action of the valves.
Figs. 4 and 5 represent another mode of applying my Invention, in which
the cylinders and valves are placed at right angles to each other, and the

page_text: power is applied to one crank B on the shaft A, and both valves are worked
by means of one excentric sheave I and strap P through rods P* at right
angles leading to the valves. The shaft A has double driving guides D, D,
on which the excentric sheave I, with its double sliding guides E, E, are
moved into their positions as required, in order to work the valves in forward
or backward or intermediate expansive action through a pair of racks F with
inclined teeth, as above described, connected to the clutch J, worked by the
starting lever O, as in the former cases.
Figs. 18 and 19 represent another mode of applying my Invention, in
which there are two excentric sheaves, one of which is moved by a pair of
sliding racks into a suitable position for working one valve as required
through a strap and rod; the second excentric sheave is on the axle and
sliding guides, and being slidden on the former one, so as to impart a
corresponding motion to the other valve. For this purpose it will be seen
that the excentric sheave I, which is acted upon by the racks F, has formed
on it two projecting sliding pieces a, a, (shewn detached at Fig. 21) in a
suitable position to allow of the second excentric sheave I*, with its sliding
guides b, b, to slide on them, so as to be adapted to work the second valve in
a manner corresponding with that in which the former valve is worked by the
former excentric sheave. The starting and reversing lever
is worked as
before, thereby sliding the pair of racks F, and moving the one excentric
sheave I into its required position on the driving guides D, and working the
valve in connection with such excentric, the other excentric sheave 1* being
at the same time slidden by its guides sliding on those of the former one,
and imparting a corresponding motion to the second valve.
From the foregoing description, and on a reference to the accompanying
Drawing, it will be seen that the machinery for working the valves under my
Invention consists (through all the modifications above described) of an
excentric sheave or excentric sheaves with sliding guides, having on their
internal surface inclined teeth of any suitable number, or pitch, or angle,
taking into which are corresponding teeth or sliding racks, moved by a clutch
on the shaft in connection with the starting and reversing lever, the excentric
sheave or excentric sheaves being thus capable of being moved into the
required position on the fixed double driving guides for working the valves
through the agency of an excentric strap and rod (or excentric straps and
rods) with a balance lever applied thereto.
It will also be seen that in double cylinder engines, with the cranks at
right angles to each other, and both valves worked by one excentric sheave
(as at Figs. 1 and 2), the valve immediately acted upon by the excentric

page_text: sheave will be that in connection with the crank at right angles to the
direction of the sliding guides on the excentric sheave through the agency of
an excentric strap and rod leading to the valve. Then the motion required
for the other valve is imparted thereto through a right-angled lever placed
loose upon the axle, or so placed upon some other point distinct from the
axle so as to enable the right-angled or bell-crank lever to receive the required
motion from the excentric sheave, such lever being acted upon in one of its
arms by a projecting piece or pin connected to the excentric strap or rod, the
motion being communicated from the other arm of the right-angled lever to
the second valve through the agency of a rod. Again, it will be seen that in
double cylinder engines, with the cranks at right angles to each other, and an
excontric sheave to work each valve (as at Fig. 3), the valve immediately
acted upon by each excentric sheave will be that in connection with each
crank at right angles to the direction of the double fixed driving guides on
the axle and double sliding guides on each side of each excentric sheave;
each sheave will have a pair of racks connected with the clutch worked by
the starting or reversing lever, but one pair of the racks will be at right
angles to the other on the axle; and it will thus be seen that each valve will
be worked from its respective excentric sheave through the agency of an
excentric strap and rod. And it will be further seen that in double cylinder
engines, with the cylinders placed at right angles to each other, and the power
applied to one crank, the valves may be worked from one excentric sheave
acted upon by a pair of racks, the motion being communicated to each valve
through two rods at right angles to each other.
Now, I would here remark, that although I have described various modes
of carrying my Invention into effect by adapting and applying it to engines of
various forms and constructions, yet my Invention is not confined to such
modes of application, but may also be adapted and applied to engines with
one cylinder, or engines with two cylinders, or engines composed of three or
four cylinders, whether condensing or non-condensing, and the cylinders
variously arranged and constructed, with various modes of construction of
the cranks.
Having thus described the nature of my Invention, and in what manner
the same is to be performed, I would have it understood that I do not claim
any of the well-known parts represented and described; but what I do claim
as of my Invention is, the application of double driving guides forged or fixed
on the crank axle or driving or intermediate shaft, and an excentric sheave or
excentric sheaves with double sliding guides on each side, and having a series
of inclined teeth on their inner surfaces, and sliding racks on the axle, with

page_text: a series of corresponding inclined teeth on each acting on the inner surface in
the excentric sheave and sliding guides, in combination with other parts for
suitably working the slide and steam valves of engines in forward, backward,
and expansive action, with a balance lever to the excentric strap, as described
in the accompanying Drawings.
In witness whereof, I, the said John Wakefield, have hereunto set my
hand and seal, the Second day of May, in the year of our Lord
One thousand eight hundred and fifty-six.
Witness,
SAM JONES,
Inchicore, Book-keeper.
JOHN WAKEFIELD. (L.S.)