IMPROVEMENTS IN THE MODE OF WORKING THE SLIDE VALVES OF STEAM ENGINES
Year: 1873

page_text: LETTERS PATENT to Thomas Moy, of 37, Farringdon Street, in the
County of Middlesex, Engineer, for the Invention of "IMPROVEMENTS
IN THE MODE OF WORKING THE SLIDE VALVES OF STEAM ENGINES."
Scaled the 10th February 1874, and dated the 11th December 1873.
PROVISIONAL SPECIFICATION left by the said Thomas Moy at the
Office of the Commissioners of Patents, with his Petition, on the
11th December 1873.
I, THOMAS MOY, of 37, Farringdon Street, in the County of Middle- -
sex, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MODE OF WORKING THE SLIDE VALVES OF STEAM
ENGINES," to be as follows:-
My Invention has for its object the working of slide valves with
increased simplicity and efficiency, and consists in the use for this
purpose of a shaft driven by bevil or other gearing at the same speed
as the main shaft of the engine, and carrying a grooved sheave or wheel

page_text: concentrically fixed thereon, but which is at the same time diagonal
thereto. By means of this arrangement on the revolution of the shaft
the grooved sheave or wheel is caused to revolve in such a manner as to
change the angle which it makes with the centre line of the shaft in the
successive parts of its revolution, thereby imparting to any mechanism
connected with it a motion similar to that caused by the revolution of
an ordinary excentric. On the said grooved sheave is fitted a strap
(similar to an excentric strap) which slides thereon, but does not turn
with it. From this strap a connecting rod serves to connect the strap with
the valve rod, the connecting rod being united to the strap by means of
an universal joint. From this connection of the parts the peculiar
motion of the grooved sheave will cause it to act upon the valve rod in
a manner similar to the action of an ordinary excentric.
A forked lever is fitted at right angles to the shaft carrying the
grooved sheave, in which forked lover the valve connecting rod works
freely, but the angle of such rod is entirely controlled by the forked
lever. By varying the angle of the said rod by means of the forked
lever the advance of the valve can be varied as required, or the engine
can be reversed.
By placing two sheaves on the same shaft both the main valve and
cut-off valve may be worked from the one shaft by means of suitable
rods or connections between the sheaves and the said valves respectively.
By altering the angle of the connecting rod of the cut-off valve the
advance will be altered, and the cut-off can be effected at any part of the
stroke of the engine.
Various modifications in the form of the said sheave may be employed,
such sheave being reduced in diameter and increased in length in order
to give greater wearing surface.
In some cases I make use of discs, and sometimes of hollow discs or
rings, hung sometimes in gimbals, sometimes on gimbals, and sometimes
on ball-and-socket joints, and communicate to such discs or rings a
vibratory motion in various ways, and obtain the aforesaid action of the
valves by attaching the valve rod or valve rods to certain points on such
discs or rings, which points can be varied and controlled by the steam
engine governor or by hand, and thereby the advance of the valve or
valves varied at pleasure.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Moy in the Great Seal Patent Office on
the 11th June 1874,
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
Mox, of 37, Farringdon Street, in the County of Middlesex, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of December, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas Moy, Her special licence that
I, the said Thomas Moy, my executors, administrators, and assigns, or.
such others as I, the said Thomas Moy, 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 THE MODE OF
WORKING THE SLIDE VALVES OF STEAM ENGINES," upon the condition (amongst
others) that I, the said Thomas Moy, my executors 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 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 Thomas Moy, 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 Drawings hereunto
annexed and to the letters and figures marked thereon (that is to
say):―
My Invention of "Improvements in the Mode of Working the Slide
Valves of Steam Engines" has for its object the working of slide valves
with increased simplicity and efficiency, and consists in the use for this
purpose of a shaft driven by bevil or other gearing at the same speed as

page_text: the main shaft of the engine, and carrying a grooved sheave or wheel
concentrically fixed thereon, but which is at the same time diagonal
thereto. By means of this arrangement on the revolution of the shaft
the grooved sheave or wheel is caused to revolve in such a manner as to
change the angle which it makes with the centre line of the shaft in the
successive parts of its revolution, thereby imparting to any mechanism
connected with it a motion similar to that caused by the revolution of
an ordinary excentric. On the said grooved sheave is fitted a strap
(analogous to an excentric strap) which slides thereon, but does not turn
with it. From this strap a connecting rod serves to connect the strap
with the valve rod, the connecting rod being united to the strap by
means of an universal joint. From this connection of the parts the
peculiar motion of the grooved sheave will cause it to act upon the valve
rod in a manner analogous to the action of an ordinary excentric.
A forked lever is fitted at or nearly at right angles to the shaft
carrying the grooved sheave, in which forked lever the valvec onnecting
rod works freely, but the angle of such rod is entirely controlled and
regulated by the forked lever. By varying the angle of the said rod by
means of the forked lever the advance of the valve can be varied as
required, or the engine can be reversed.
By placing two sheaves on the same shaft both the main valve and
cut-off valve may be worked from the one shaft by means of suitable
rods or connections between the sheaves and the said valves respectively.
By altering the angle of the connecting rod of the cut-off valve the
advance will be altered, and the cut-off can be effected at any part of the
stroke of the engine.
Various modifications in the form of the said sheave may be employed,
such sheave being reduced in diameter and increased in length in order
to give greater wearing surface.
In some cases I make use of discs, and sometimes of hollow discs or
rings, hung sometimes in gimbals, sometimes on gimbals, and sometimes
on ball-and-socket joints, and communicate to such discs or rings a
vibratory motion in various ways, and obtain the aforesaid action of the
valves by connecting the valve rod or rods to certain points on such
rings or discs, which points can be varied and controlled by the steam
engine governor or by hand, and thereby the advance of the valve or
valves varied at pleasure.

page_text: descrive more partially in what man sa
by the aid of the accompanying Drawings, in which is represented the
mode of working slide valves in the manner above referred to.
DESCRIPTION OF THE DRAWINGS.
Figures 1 and 2 represent a disc mounted in gimbals, which disc has
a rod connected to its centre at right angles to its face. On rotary
motion being imparted to the end of the rod, so that such rod during
such motion is caused to travel in a conical path at a constant angle
from the perpendicular, every part of the disc, except its centre, will
successively receive a reciprocating motion.
At Fig. 3 is represented a disc, which is mounted in gimbals as afore-
said, and without such rod, as above described, but at distances of one
hundred and twenty degrees apart; three connecting rods are connected
thereto, and also to three excentrics fixed on an axle at angles equi-
valent to one hundred and twenty degrees from each other; such disc
so mounted will receive a similar motion to that before described and
shewn in Figures 1 and 2.
Fig. 4 represents a disc mounted as aforesaid, which is made to receive
one complete motion during one revolution of a steam engine crank
shaft, and from which a suitable connection is made to the valve rod of
a steam engine. By this means the valve may be driven instead of by
an ordinary excentric, and by varying the point of connection to the
disc the working of the valve may be suited to forward a backward
motion of the engine. The disc should be dished (as shewn) to the
radius of the valve connecting rod.
If a disc mounted and actuated by any of the means herein-before
described be used to work the expansion valve of a steam engine the
degree of expansion of the steam may be controlled and varied as
required, either by hand or by the governor rod. The amount of
expansion will depend upon the point on the face of the disc where the
connection is formed, and by making such point of connection to vary,
the amount of expansion will correspondingly vary..
In Fig. 5 an arrangement is shewn whereby one valve can be worked
by a modification of the plans described in Figures 1, 2, 3, and 4. In:

page_text: Fig. 5 a is the main axle; b is an auxiliary axle; c, c¹, are mitre
wheels of equal diameters; d is an axle which revolves with the mitre
wheel c¹, and travels in a conical path. This axle d receives a collar e,
which carries the valve connecting rod f; 9 is a lever, which may be
moved by hand, and works upon a fulcrum at h, one end of the lever 9 5
being forked or slotted to receive the connecting rod f. By working the
lever the direction of the steam engine may be reversed and the
amount of advance and lead may be varied. Fig. 5ª represents a plan
view of the lever g.
In Fig. 6 an arrangement is shewn whereby two valves may be 1
worked from the axle d. The parts lettered from a to d denote parts
similar to those in Fig. 5, the collar e with valve connecting rod f
working the main valve, as in Fig. 5, and the collar e¹ and expansion
valve connecting rod f¹ working the expansion valve on the back of the
main valve. The lips of the expansion valve are at fixed distances apart 1
and do not require to be altered.
In Fig. 7 another arrangement is shown for producing the motion of
valves. A double arm h, h, works on an axle i, as shewn, each having a
partially rotary motion at right angles to the other.
k, Fig. 7, is a rod which is caused to follow a conical path by means of 2
the mitre wheel c¹ and radial arm e²; a sliding block 7, Fig. 7, carries
the valve connecting rod, the position of this block being controlled
by a lever similarly to that shewn in Fig. 5.
In Fig. 8 is represented a modification of Fig. 7, whereby two valves
can be worked similarly to that shewn in Fig. 6.
Figures 9, 10, and 11 shew three several modifications of the means
of obtaining the motion. In Fig. 9 it is represented merely as a sheave
and strap diagonally fixed on an axle; in Fig. 10 the strap is made
broader; and in Fig. 11 two straps are fitted, as shewn.
in a similar manner.
These all work
The main valve may in some cases be worked by two excentrics and a
link and the expansion valve by any of the means aforesaid.
3
Having thus described the nature of the said Invention and in what
manner the same is to be performed, I hereby declare that I do not claim
as of my Invention any of the mechanism herein-before referred to, 3
except in connection with valves worked by means of grooved sheaves

page_text: or discs diagonally mounted, as described, but what I do claim as of my
Invention is, the mode described of working slide valves by means of
grooved sheaves or discs diagonally mounted in such a manner as to
adapt them to convey to such valves through suitable mechanism a
motion analogous to that caused by the revolution of an ordinary
excentric, thereby affording increased facility for altering the angle of
advance no requined
In witness whereof, I, the said Thomas Moy, have hereunto set
my hand and scal, the Eleventh day of June, in the year of our
Lord One thousand eight hundred and seventy-four.
Witness,
WILLIAM SPENCE,
8, Quality Court,
Chancery Lane.
THO. MOY. (L.S.)