A MODE OF VARYING THE LENGTH AND REVERSING THE DIRECTION OF THE THROW OF EXCENTRICS, APPLICABLE TO THE REVERSING GEAR OF LOCOMOTIVES, AND EXPANSION GEAR OF OTHER STEAM ENGINES, AND TO OTHER PURPOSES
Year: 1857

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents, 66,
Chancery Lane, in the County of Middlesex, Mechanical Draughtsman,
for the Invention of "A MODE OF VARYING THE LENGTH AND REVERSING
THE DIRECTION OF THE THROW OF EXCENTRICS, APPLICABLE TO THE REVERSING
GEAR OF LOCOMOTIVES, AND EXPANSION GEAR OF OTHER STEAM ENGINES, AND TO
OTHER PURPOSES."-A communication.
Sealed the 25th March 1858, in pursuance of an Order of the Lord Chan-
allan and dated the 95th August 1857
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton
at the Office of the Commissioners of Patents, with his Petition, on the
25th August 1857.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery
Lane, in the County of Middlesex, Mechanical Draughtsman,. do hereby
declare the nature of the said Invention for "A MÓDE OF VARYING THE LENGTH
AND REVERSING THE DIRECTION OF THE THROW OF EXCENTRICS, APPLICABLE TO THE
REVERSING GEAR OF LOCOMOTIVES, AND EXPANSION GEAR. OP OTHER STEAM ENGINES,
AND TO OTHER PURPOSES," to be as follows:-
This Invention relates to a mode of applying a doublé oblique slide to an
excentric to vary or reverse the throw thereof by moving the said slide
longitudinally to the axis of the shaft of the excentric. The Invention is
particularly applicable to the valve excentrics of locomotives and other steam

page_text: engines, supplying the place of the link motion, for, by a proper arrangement
of the parts, a constant "lead" of the valve under all the required changes of
condition of the excentric is provided for.
The excentric shaft which, to illustrate the application of the Invention
to a steam engine, is represented with a crank at one end, is made square
for a considerable portion of its length, but provided with journals fitted
to rotate in bearings in two fixed standards. Upon the square part of
the shaft works a double oblique slide, consisting of a block of metal having
a square hole in it to receive the shaft, and having two of its sides parallel
longitudinally with its square hole, and its other two sides parallel with each
other, but at an angle of about 15° to the square hole.. In the excentric a slot
is cut obliquely to receive the double oblique slide, and ensure the parallelism
of the axis of the excentric with that of the shaft. Two standards with circular
heads are secured on opposite sides of the excentric, and serving to prevent it
moving laterally, while it is free to rotate. These standards have open circular
heads, through which the double oblique slide is capable of working freely.
This slide is connected by a loose collar and link to a hand lever, the move-
ment of which will cause the slide to traverse in the slot of the excentric, and
increase or diminish the amount of its excentricity, or reverse the direction of
the throw of the excentric, as required..
SPECIFICATION filed in pursuance of the conditions of the Letters Patent,
and of an Order of the Lord Chancellor, by the said Alfred Vincent
Newton in the Great Seal Patent Office on the 25th March 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Mechanical Draughtsman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of August, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Alfred Vincent Newton, Her special license that I, the said
Alfred Vincent Newton, my executors, administrators, and assigns, or such
others as I, the said Alfred Vincent Newton, 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

page_text: of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "A MODE OF VARYING THE LENGTH AND REVERSING THE DIRECTION
OF THE THROW OF EXCENTRICS, APPLICABLE TO THE REVERSING GEAR OF LOCOMOTIVES,
AND EXPANSION GEAR OF OTHER STEAM ENGINES, AND TO OTHER PURPOSES," being
a communication from abroad, upon the condition (amongst others) that I,
the said Alfred Vincent Newton, by an instrument in writing under my
hand and seal, 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 on or before.
the Twenty-fifth day of March, One thousand eight hundred and fifty-eight.
NOW KNOW YE, that I, the said Alfred Vincent Newton do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, 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) :-
This Invention as communicated to me by my foreign correspondent relates
to the application of a double oblique slide to an excentric for the purpose of
varying or reversing the throw thereof, by simply moving the slide longi-
tudinally to the axis of the shaft of the excentric.
The Invention is particularly applicable to the valve excentrics of locomotive
and other steam engines, supplying the place of the link motion than which it
is much more simple; for, by a proper arrangement of the parts, a constant
"lead" of the valve under all the required changes of condition of the
excentric is provided for.
The Invention is illustrated in the accompanying Drawings, in which Fig. 1
is a front view, partly in section, of a shaft carrying an excentric fitted with
the double oblique slide; Fig. 2 is a plan of the same; Fig. 3 is a transverse
section of the excentric, the shaft, and the double oblique slide. Similar
letters of reference indicate corresponding parts in the several Figures.
A is the shaft which carries the excentric, and is furnished with a crank G
at one end, for the purpose of illustrating the application of the Invention to a
steam engine. This shaft is made square for a considerable portion of its
length, but provided with journals fitted to rotate in bearings in two fixed
standards S, S; B is the double oblique slide consisting of a block of
metal having a square hole in it to fit the square portion a, a, of the shaft
A, upon which it is intended to slide, and having two of its sides b, b
parallel longitudinally with the square hole, and the other two sides c, c,
parallel with each other, but at an angle of about fifteen degrees to the square
hole. C is the excentric through which a slot is cut obliquely to receive the
3

page_text: dowble oblique slide B, the obliquity of the slot being at the same degree
relatively to the axis of the excentric, as the obliquity of the two sides c, c,
of the slide B are to the interior of the hole in the slide, so that the
axis of the excentric when it is placed on the slide and the slide placed on the
shaft will be parallel with the axis of the shaft. D, D, are two standards
with circular heads secured on opposite sides of the excentric C, and serving
to prevent it moving lengthwise of the shaft, but not preventing the rotary
motion of the excentric. These standards have open circular heads which are.
concentric to the shaft, and through which the double oblique slide B is
capable of working freely; E is a lever for moving the double oblique slidė
longitudinally upon the shaft, having its fulcrum at e, and being connected
with the slide by means of a rod f, and a loose collar g, in which the slide
is permitted to turn with the shaft; F is a fixed sector-shaped frame, to which
the lever E is capable of being clamped by a clamp h and set screw.i, to hold:
the slide B in various positions.
The excentric C rotates with the shaft A, in the same manner as if it were
keyed thereon, as the square on the shaft causes the slide B to rotate with it,
and the slide B carries the excentric. The throw of the excentric may be
varied, or its direction entirely revered, either while the shaft is at rest or in
motion, by moving the lever E by hand. The slide B is thus caused to move
along the shaft, and its oblique sides c, c, acting as wedges against the cor-
responding sides of the slot in the excentric C move the excentric transversely
to the shaft and at right angles to the position of the crank. The shifting
of the excentric is illustrated in Fig. 1, where in black outline it is shewn as
projected from one side of the shaft, and in red outline as projected in
a corresponding degree from the opposite side; the relative positions of the
lever and slide in both cases being shewn in corresponding outlines. The two
positions of the excentric are also shewn in Fig. 3, where it will be seen that.
one position is precisely the reverse of the other relatively to the crank.
In Fig. 3 the slot which receives the oblique slide is represented as
made precisely in the centre of the excentric and the axis of the shaft
arranged precisely in the centre of the double oblique slide. Such an arrange-
ment applied to the valve or valves of a steam engine would admit of no
"lead" being given, as the excentric, if adjusted to give a "lead" in running
the engine in one direction, would cause the valve to be as far behindhand
in running it in the opposite direction. Fig. 4 is a side view of an ex-
centric and a transverse section of a double oblique slide and shaft fitted up
in substantially the same manner as before described, but having provision
made for giving a constant "lead" to a valve in every condition of the excentric.

page_text: In this Figure C¹ is the excentric; A', the shaft; and B', the double oblique
slide. It will be seen that the slot in the excentric in which the double
oblique slide is received is arranged some distance out of the centre of the
excentric, in a direction at right angles to the direction of the adjustment 1
of the excentric by the slide B', and if this adjustment is at exactly
right angles to the crank G¹, the setting of the slot out of centre in the
direction described will give the same "lead" to the valve whether the ex-
centric be set for running forward' or reversed, and this "lead" varies very
little with such changes in the throw of the excentric as are required to vary
the stroke of the valve, to suit the desired cut-off. It is obvious that the
same adjustment for "lead," as is illustrated in Fig. 4, may be obtained by
arranging the slide B excentrically to the shaft, in the same direction as the
excentricity of the slot represented in Fig. 4, and making the slot in the centre
of the excentric, and that such an arrangement would be equivalent to that
illustrated in Fig. 4.
Having now set forth the nature of the Invention of "A Mode of Varying
the Length and Reversing the Direction of the Throw of Excentrics, appli-
cable to the Reversing Gear of Locomotives, and Expansion Gear of other
Steam Engines, and to other Purposes," as communicated to me by my
foreign correspondent, and explained the manner of carrying the same into
effect, I wish it to be understood that under the above in part recited
Letters Patent, I claim the employment of a double oblique slide fitted
to the shaft of the excentric, and acting substantially as described, in com-
bination with suitable means for preventing the movement of the excentric in
a direction longitudinal to the shaft.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto
set my hand and seal, the Twenty-fifth day of March, in the year
of our Lord One thousand eight hundred and fifty-eight.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
A. V. NEWTON. (L.S.)