AN IMPROVEMENT IN VARIABLE CUT-OFF GEAR FOR PRO- DUCING EXPANSION IN STEAM AND OTHER MOTIVE ENGINES
Year: 1859

page_text: દ
LETTERS PATENT to William Edward Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Civil Engineer, for
the Invention of "AN IMPROVEMENT IN VARIABLE CUT-OFF GEAR FOR PRO-
DUCING EXPANSION IN STEAM AND OTHER MOTIVE ENGINES."-A communi-
cation from abroad by Ambrose Foster, Noah Sutton, and James
Stephens, all of New York.
Sealed the 29th November 1859, and dated the 28th June 1859.
PROVISIONAL SPECIFICATION left by the said William Edward Newton
at the Office of the Commissioners of Patents, with his Petition, on
the 28th June 1859.
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery
Lane, in the County of Middlesex, Civil Engineer, do hereby declare the
nature of the said Invention for "AN IMPROVEMENT IN VARIABLE CUT-OFF GEAR
FOR PRODUCING EXPANSION IN STEAM AND OTHER MOTIVE ENGINES," to be as
follows:-
This Invention consists principally in the employment (for operating either
the main valve or valves of an engine or a separate cut-off valve or valves) of
a compound cam composed of two parts yoked or combined together, and
applied either upon the main shaft of the engine or upon a counter-shaft, and
serving to effect. the cutting off of the supply of steam from the boiler to the
cylinder at various points in the stroke of the piston, either under the control
of a governor, or of any contrivance at the command of the engineer.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Edward Newton in the Great Seal Patent Office
on the 28th December 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of June, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-third year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said William Edward Newton, Her special license that I, the
said William Edward Newton, my executors, administrators, and assigns,
or such others as I, the said William Edward Newton, my executors, admi-
nistrators, 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 "AN IMPROVEMENT IN VARIABLE CUT-OFF GEAR FOR PRODUCING
EXPANSION IN STEAM AND OTHER MOTIVE ENGINES," being a communication from
abroad, upon the consideration (amongst others) that I, the said William
Edward 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 within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Edward Newton, do hereby
declare the nature of the 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 hereunto annexed,
.and to the letters and figures marked thereon (that is to say):-
This Invention consists principally in the employment for operating either
the main valve or valves of an engine, or a separate cut-off valve or valves of
a compound cam composed of two parts yoked or combined together, and
applied either upon the main shaft of the engine, or upon a counter-shaft, and
serving to effect the cutting off of the supply of steam from the boiler to the
cylinder at various points in the stroke of the piston, either under the control
of a governor, or of any contrivance at the command of the engineer.
In the accompanying Drawing Fig. 1 exhibits a vertical section of a cut-off

page_text: gear, with the improvement adapted to an engine with slide valves; Fig. 2 is
a plan of the same; Figures 3 and 4 exhibit the sectional form of the cam
near the two ends; Fig. 5 is a side view, illustrating the application of the
cut-off gear to an engine with puppet valves. Similar letters of reference
indicate corresponding parts in the several Figures.
A (Figures 1, 2, 3 and 4,) is the shaft which carries the compound eam,
and which may be supposed to be either the main shaft of the engine; or a
counter-shaft deriving motion therefrom at the same velocity; B; B, are the
bearings in which the said shaft is supported; C and D are the two parts of
the compound cam, of which the part C is keyed or otherwise secured in a
fixed position on the shaft, and the part D is fitted so that it may both slide
and turn on the shaft; E is a yoke, within which the cam acts to operate the
valves, having two straight stems a, a, fitted to slide in fixed guides F, F, and
having an antifriction roller b at each end for the cam to act upon to give it
the necessary reciprocating motion. The part C of the cam need not have its
face wider than is necessary to constitute a bearing for the rollers b, b, as it is
never shifted in the direction of the length of the shaft; but the part D must
be of considerable width, say, about equal to twice its diameter; and the
latter contains two spiral grooves e, c, extending nearly or quite from end to
end to receive the two wings d, d, of the part C, which fit within the said
grooves, and so cause the part C to carry the part D round with it in the
revolution of the shaft. The part D, which consists of a mere sell, may be
made in two or more pieces, in order to get the part C inside of it. The
perimeter or face of the cam is composed of four are-formed portions, e¹, e³, e³, e',
concentric with the shaft A, and four intervening steps f', f, f, f, the steps
ff, being on the part C, and the steps f², f, on the part D, and the arc-
formed portions being each partly on the part C and partly on the part D, as
shewn in Figures 1, 3, 4 and 5. The face is in all parts parallel with the
shaft A, but the length of the several are-formed portions e', e², e³, e, taken im
a circumferential direction varies from one end of the cam to the other, owing
to each of said arc-formed portions terminating in one direction in one edge
of one of the spiral grooves, and in the other direction in the steps which run
parallel with the shaft. This variation in the length of the ares is illustrated
by Fig. 1, 3 and 4, which represent sections of the same cam at three different
points. Fig. 1 representing a section at the middle of the cam; Fig. 3, a
section near the end, which is at the bottom of Fig. 2; and Fig. 4, a section
near the end, which is at the top of Fig. 2. In each of the Figures 1, 3
and 4, the part C of the cam is supposed to be close to the plane of section.
By shifting the part D along the shaft A, different parts of it are made to

page_text: unite with the part C to operate upon the yoke to give it an intermittent
reciprocating motion, and though owing to the several steps of the cam being
of the same height from end to end of the cam, the throw or distance of
movement of the yoke never varies, yet the length of time the yoke remains
stationary at each end of the stroke will be greater or less as the part D of
the cam presents longer or shorter portions of the arcs e', e', within the yoke.
I (Fig. 2) is a screw having journals at its ends fitted to turn in stationary
bearings J, J, but prevented from moving longitudinally, the screw I being
parallel with the shaft A; K is a forked arm having its fork fitted to a
groove in a boss on the end of the part D of the cam, and having at the
opposite end to the fork an internally screwed socket which fits the thread of
the screw I. The screw is provided with a bandle I, to enable it to be turned
by the engineer, for the purpose of causing the arm K to travel along it, and
thus shift the part D of the cam C, D, along the shaft A. G (Fig. 1) is the
valve chest of the engine, and is furnished with two short slide valves H, H',
of a well-known kind; j is the stem of the valves connected by a rod k with
the cam yoke E; g, g', are the steam ports; and h, h¹, the exhaust ports.
The step of the compound cam produces the movement necessary to open
the steam ports for each stroke of the engine by its action upon the two
rollers of the yoke alternately; the opposite arcs e¹, e³, which have a corre-
sponding length in a circumferential direction, keep the valve open till the
steam is to be cut off; the step facts upon the rollers to cut off the steam,
and the arcs e, e', hold the valves in a position to keep the steam cut off. The
steps f, fs, are merely to permit the operations of f¹, f, and to allow both
rollers to follow the surface of the cam.
The part C of the cam is so set on
the shaft, that the step f¹ always commences operating on one or the other
roller just as the stroke of the engine piston terminates. The cam rotates in
the direction of the arrow shewn upon it in Fig. 1. The position there
represented is, that after the steps f. f, have just passed the rollers, and the
former has just shifted the valves in the direction of the arrow, shewn on their
stem, to cut off steam from the part g by its action on the left-hand roller b,
and no further movement of the valve will take place till the step f¹ comes
into action on the aforesaid roller b, and gives the valves a further movement
in the same direction, to admit steam to the port g' and open g to the exhaust
port h.
When the step f' passes the right-hand roller b, it will produce the
movement of the valves in the opposite direction as far as is necessary to close
the port g¹ to the steam, and while the arcs e², e, pass between the rollers, the
valves will remain stationary in that position; but when the step f¹ comes
into operation on the right-hand roller, it will produce the further movement

page_text: of the valves in the last named direction to, open the port g to the steam, and
to also open g¹ to the exhaust port h¹, and in this way the operation proceeds,
the ports being open to the steam during a greater or less portion of the
revolution, according to the position of the part D relatively to the part C,
and the length of the shaft. The same operation will be produced with a
single valve and three ports.
It will be observed by reference to Figures 1, 3 and 4, that the arc e² of
the cam has a somewhat greater radius than the opposite arc e. This is for
the purpose when the valves are moved far enough to cut off the steam from
either port g or g¹, of allowing the other of the ports to remain a little way
open to its exhaust port. A proper construction of the valves will, as well-
understood by engineers, be also necessary in connection with the can. This
compound cam may be constructed to give any required amount of variation
in the point of cutting off the steam, to use it expansively during the remainder
of the stroke of the piston, by making the spiral grooves c, c, of a suitable
pitch, so as to give the desired variation in the length of the arcs in a cir-
cumferential direction. The cam for operating two puppet induction and cut-
off valves represented in Fig. 5 is like that shewn in Figures 1, 2, 3, 4 in
every respect, but that the arcs e² and e* have a precisely similar radius, and
the yoke is constructed and applied in precisely the same manner, as will be
understood by a comparison of the Fig. 5 with the Fig. 1. M (Fig. 5) is the
way shaft for operating the valves furnished with two toes m, m', viz, one for
each valve, and with an arm N, which is connected by a rod n with the yoke.
The several arcs and steps of this cam perform the same functions as the
corresponding parts of the cam applied to the slide valves. When the valves
are both closed, and the arcs e², e, are between the rollers b, b, the arm N is
vertical, but as the step f¹ comes into operation upon the two rollers b, b,
alternately, it causes the arm N to be moved first in one and then in the other
direction from the vertical position, and so to raise each toe and cause each
valve to be opened in its turn. The operation of the step f* intervening
between those of the step f', returns the arm N to the vertical position, and
leaves it so till the step f¹ operates again, and so permits the valves to close
and cut off the steam at the proper time. Any method of operating the
exhaust valves may be applied in connection with this cam.
In applying the compound cam to work a separate cut-off, independent of
the main valve or valves, it may be constructed as shewn in Fig. 5, and the
yoke and all its appendages may have the same construction as represented in
the several Figures. Its connection with the cut-off must be such as to open
and close it during the movement of the yoke in either direction. When the

page_text: compound cam is applied in combination with a governor, the part D is con-
nected with the governor in such a manner, that by the action of the latter
said part may be moved in one or the other direction along the shaft, to cut
off steam sooner or later in the stroke of the engine, as may be required to
regulate the speed.
Having now described the Invention that has been communicated to me as
aforesaid, and having explained the manner of carrying the same into effect, as
described by my foreign correspondent, I claim as the Invention secured to me
by Letters Patent as aforesaid, the employment for operating either the main
valve or valves of an engine, or a separate cut-off valve or valves, of a com-
pound cam composed of two parts C and D, constructed and combined with
each other, and applied to the main or a counter-shaft, substantially as herein
described.
In witness whereof, I, the said William Edward Newton, have hereunto
set my hand and seal, the Twenty-seventh day of December, in the
year of our Lord One thousand eight hundred and fifty-nine.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
W. E. NEWTON. (L.S.)