IMPROVEMENTS IN SLIDE VALVES FOR STEAM AND OTHER ENGINES
Year: 1874

page_text: LETTERS PATENT to Joseph Ruston, of the Sheaf Ironworks, in the
City of Lincoln; for the Invention of "IMPROVEMENTS IN SLIDE VALVES
FOR STEAM AND OTHER ENGINES."
Sealed the 5th February 1875, and dated the 5th September 1874.
PROVISIONAL SPECIFICATION left by the said Joseph Ruston at the
Office of the Commissioners of Patents, with his Petition, on the
6th September 1874.
I, JOSEPH RUSTON, of the Sheaf Ironworks, in the City of Lincoln, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
SLIDE VALVES FOR STEAM AND OTHER ENGINES," to be as follows :—
This Invention has for its object improvements in slide valves for
steam and other engines.
The ports of the cylinder are made in the same manner as for the
ordinary short slide valve. Within the valve box and working face to
face with the ports there is a slide. The central portion of the slide is
of form (like the ordinary slide), and it is long enough to cover

page_text: the three ports. At each end of the slide there is a slot or steam
port. This slide is worked to and fro by a single eccentric on the crank
shaft. Two cut-off valves are mounted to slide in guides on the back of
the valve to open and close the steam ports in it. Each cut-off valve is
provided with two horns and between the horns there is a stop.
During the first portion of the motion of the slide in either direction
it carries the cut-off valves with it as far as the stops admit, and then
by the further motion of the slide the cut-off valves are moved in their
guides on the back of the slide, uncovering one of its steam ports and
covering the other.
.
The cut-off valves always traverse the same distance, but by shifting
the stops the position of their paths on the back of the slide can be
varied, and consequently the steam ports through the slide by which the
steam passes into the cylinder will be opened sooner or later in accordance
with the position given to the stops.
The stops are under the control of the governor and when they are
moved towards each other the portion of the stroke, during which.
steam is admitted is increased. On the contrary, when the distance
between the stops is increased the cut-off takes place sooner. One
stop is carried by a rod and the other by a tube through which the
rod passes. The tube passes out through a stuffing box in the end of
the valve box, and the rod works steam-tight in the tube. The rod and
tube are so geared to the governor that as the speed of the engine varies
they move in opposite directions. One convenient method of giving
this motion to the rod and tube is to connect them by means of con-
necting rods to studs at the ends of a diameter of a disc which is caused
to turn to or fro by the governor as the speed of the engine varies.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Joseph Ruston in the Great Seal Patent Office
on the 5th March 1875.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of September, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Joseph Ruston, Her special license
that I, the said Joseph Ruston, my executors, administrators, and
assigns, or such others as I, the said Joseph Ruston, 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
SLIDE VALVES FOR STEAM AND OTHER ENGINES," upon the condition (amongst
others) that I, the said Joseph Ruston, my executors or admini-
strators, 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 Joseph Ruston, 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 thereof, that is to say :-
-
5 This Invention has for its object improvements in slide valves for
steam and other engines.
The ports of the cylinder are made in the same manner as for the
ordinary short slide valve. Within the valve box and working face to
face with the ports there is a slide. The central portion of the slide
) is of
form like the ordinary slide, and it is long enough to
cover the three ports. At each end of the slide there is a alot or steam
port. The slide is worked to and fro by a single eccentric on the crank
shaft. Two cut-off valves are mounted to slide in guides on the back of
the valve to open and close the steam ports in it. Each cut-off valve is
5 provided with two horns and between the horns there is a stop, or each
cut-off valve may be provided with a single horn to work between a pair
of stons.

page_text: During the first position of the motion of the slide in either it carries
the cut-off valves with it as far as the stops admit, and then by the
further motion of the slide the cut-off valves are moved in their guides
on the back of the slide, uncovering one of its steam ports and covering
the other.
The cut-off valves always traverse the same distance, but by shifting
the stops the positions of their paths on the back of the slide can be
varied, and consequently the steam ports through the slide by which the
steam passes into the cylinder will be opened. sooner or later in
accordance with the position given to the stops.
The stops are under the control of the governor, and when they aro
moved towards each other the portion of the stroke during which steam
is admitted to the cylinder is increased. On the contrary when the
distance between the stops is increased the cut-off takes place sooner.
One stop or pair of stops is carried by a rod and the other-by-a-tube
through which the rod passes. The tube passes out through a stuffing box
in the end of the valve box, and the rod works steam-tight in the tube.
The rod and tube are so geared to the governor that as the speed of the
engine varies they move in opposite directions. One convenient method
of giving this motion to the rod and tube is to connect them by means
of connecting rods to studs at the ends of a diameter of a disc which is
caused to turn to or fro by the governor as the speed of the engine
TAXIAS

page_text: pass through. The two spindles may be moved backwards and forwards
each independently of the other. Upon the usual forked lever spindle g
of the governor is fixed a double lever h, the arm i is connected by the
link; to the hollow brass spindle at k, the arm 2 is connected by the
link m to the internal spindles at n.
The action is as follows:-The slide valve A gives motion to the
expansion valves b, b', until they are arrested by the forked stops O, O',
the slide valve continues its motion until the steam is cut off by the
ports in the slide valve passing under the expansion valve. This action
is repeated during the backward and forward strokes of the piston, one
forked stop serving to open the steam port on one side and the other
closing the one on the other side.
It will be readily seen that as the governor rises or falls the hollow
spindle d and the internal spindle e are moved backward and forward
by the action of the double lever h, and the forked stops C, C¹, are caused
to approach nearer together or move further apart, thereby altering the
point when the motion of the expansion valves is arrested, and
conseqently the cut-off of steam is varied.
Having thus described the nature of my Invention and the manner of
performing the same, I would have it understood that I claim, the
arrangement of a pair of cut-off valves on the back of a slide valve, such
cut-off valves having their movement controlled by stops operated by the
governor, substantially as herein described.
In witness whereof, I, the said Joseph Ruston, have hereunto
set my hand and seal, this Fourth day of March, in the year
of our Lord One thousand eight hundred and seventy-five.