IMPROVEMENTS IN REGULATING AND WORKING THE SLIDE
Year: 1875

page_text: LETTERS PATENT to John Wakefield, Engineer, of the Vulcan
Foundry, Brynmaur, in the County of Brecknock, Wales, for the
Invention of "IMPROVEMENTS IN REGULATING AND WORKING THE SLIDE
33
Scaled the 23rd July 1875, and dated the 9th April 1875.
PROVISIONAL SPECIFICATION left by the said John Wakefield at
the Office of the Commissioners of Patents, with his Petition, on
the 9th April 1875.
I, JOHN WAKEFIELD, Engineer, of the Vulcan Foundry, Brynmaur,
in the County of Brecknock, Wales, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN REGULATING AND WORKING THE SLIDE
VALVES OF STEAM AND OTHER ENGINES," to be as follows -
The object of this Invention is to simplify the construction of engines,
and to economise the steam, air, water, or gas as motive power by intro-
ducing an improved slide valve gear. This gear is applicable to single or
For a single
double engines, and does away with the slot link motion.
engine it is complete with one eccentric cam and one rod, and requires

page_text: neither weigh shaft nor balance
In the case of double engines there
One end of the eccentric rod is
are two eccentric cams and two rods.
connected with a shaft, to which is attached the reversing lever.
Attached to the eccentric rod are two links, the lower extremities of
which are connected with a bell crank, which is jointed to the slide
valve rod.
When the reversing lever is in an upright position the travel of the
valve is regulated by the diameter of cam, giving a greater or lesser
angle to the eccentric rod, and thereby raising or lowering the links
attached to the bell crank, which gives the required motion to the slide
valve. When the reversing lever is moved to forward or backward gear
it gives the required angle to the disc to which it is attached, thereby
giving the proper travel to the slide valve.
By this gearing any engine or engines can be reversed with full steam
on, and it permits the working of the engine or engines with much 1
greater facility and precision than ordinary.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Jolin Wakefield in the Great Seal Patent Office
on the 2nd September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN 1
WAKEFIELD, Engineer, of the Vulcan Foundry, Brynmaur, in tho
County of Brecknock, Wales, send grecting
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of April, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty- 2
eighth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Wakefield, Her special licence that
I, the said John Wakefield, my executors, administrators, and assigns,
or such others as I, the said John Wakefield, my executors, admini-
strators, and assigns, should at any time agree with, and no others, from 3
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 Britam and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN REGULATING AND

page_text: WORKING THE SLIDE VALVES OF STEAM AND OTHER ENGINES," upon the con-
dition (amongst others) that I, the said John Wakefield, my exccutors
or administrators, by an instrument 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 Scal 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, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Sheet of
Drawings, that is to say :-
The object of this Invention is to simplify the construction of engines,
and to economise the steam, air, water, or gas as motive power by intro-
ducing an improved slide valve reversing gear. This gear is applicable
to single or double engines, and does away with the slot link motion.
For a single engine it is complete with one eccentric cam and one rod,
and requires neither weigh shaft nor balance. In the case of double
engines there are two eccentric cams and two rods. One end of the
eccentric rod is connected with a shaft, to which is attached the
reversing lever. Attached to the eccentric rod are two links, the lower
extremitics of which are connected with a bell crank, which is also con-
nected with the slide valve rod by means of two links or other suitable
mechanical appliance.
When the reversing lever is in an upright position, that is to say, in
the middle notch of a disc to which it is attached, the travel of the valve
is regulated by the diameter of cam, giving a greater or lesser angle to
the eccentric rod, and thereby raising or lowering the links attached to
it and to the bell crank, which gives the required motion to the slide
valve. When the reversing lever is moved to forward or backward gear
it gives the required angle to the disc, thereby giving the proper travel
to the slide valve.
on
By this gearing any engine or engines can be reversed with full steam
and it nommate the maubing
the

page_text: In order that my Invention may be more fully understood, I will
proceed to describe the same by aid of the accompanying Sheet of
Drawings, which represents the improved reversing gear applied to a pair
of winding engines, but it is applicable to all kinds of steam, air, water,
or gas engines requiring to be reversed
Fig. 1 is a plan; Fig. 2, an clevation; and Fig. 3, a part section
through A, B, and C, D.
Attached to the eccentric rod G are the two links F, F, the lower
extremities of which are connected with the bell crank E, E, which is
also connected with the slide valve rod R by means of two links e, e, or
other suitable mechanical appliance. When the reversing lever L is
in the middle notch of disc d, as shown in the Drawings, the valve only
travels the lap, and it is regulated by the diameter of cam, giving a
greater or lesser angle to the eccentric rod G, and thereby raising or
lowering the links F, F, attached to it and to the bell crank E, E, which
gives the required motion to the slide valve; but when the reversing
lever L is moved to forward or backward gear notch it gives the required
angle to the disc d to which it is attached, thus giving the
to the slide valve.
proper
travel
Having now described the object of my Invention and the manner in
which the same is to be carried out, I would observe that what I claim
as my Invention for "Improvements in Regulating and Working the
Slide Valves of Steam and other Engines" is, the disc and combination
of links attached to the eccentric rod, and the bell crank connected with
the lower extremities of these links and also to the slide valve rod by
means of links or other suitable mechanical appliance, as described in
the Specification and shown in the Drawings.
Although I have only described and shown my Invention as applied
to a pair of winding engines, I claim the same as applied to all kinds of
steam, air, water, or gas engines requiring to be reversed.
In witness whereof, I, the said John Wakefield, have hereunto set
my hand and seal, this Ninth day of August, in the year of our
Lord One thousand eight hundred and seventy-five.