IMPROVEMENTS IN THE MACHINERY OR APPARATUS FOR ACTUATING THE SLIDE VALVES OF MARINE ENGINES AND IN THE SLIDE VALVES THEREOF
Year: 1865

page_text: LETTERS PATENT to John Robertson, of Glasgow, in the County of Lanark,
North Britain, for the Invention of "IMPROVEMENTS IN THE MACHINERY
OR APPARATUS FOR ACTUATING THE SLIDE VALVES OF MARINE ENGINES AND IN
THE SLIDE VALVES THEREOF."
Sealed the 1st December 1865, and dated the 5th June 1865.
PROVISIONAL SPECIFICATION left by the said John Robertson at the
Office of the Commissioners of Patents, with his Petition, on the 5th
June 1865.
I, JOHN ROBERTSON, of Glasgow, in the County of Lanark, North Britain,
do hereby declare the nature of the said Invention of "IMPROVEMENTS IN
THE MACHINERY OR APPARATUS FOR ACTUATING THE SLIDE VALVES OF MARINE
ENGINES AND IN THE SLIDE VALVES THEREOF," to be as follows, this is to say:-
This Invention relates to a certain new arrangement of slide valves and
apparatus for working the same, both of which are especially applicable to
marine engines.
One modification of this Invention consists in doing away with the ordinary
slide valve altogether, and substituting in lieu of it two or more valves driven
by means of a cam on the driving or other shaft; in this cam an oblique
groove is cut along part of its circumference, into which groove the end of a
rod passes, and as the cam revolves it by means of the oblique groove imparts

page_text: to the rod an alternate backward and forward movement, which motion is
communicated by means of tappets to the sliding plates herein-before referred
The exhaust valve is in this modification similar to the sliding valve and
is actuated by similar mechanism; the exhaust valves may be situated in
the same chamber as the admission valves or they may be placed in separate
chambers.
Under another modification of this Invention at each end of the ordinary
slide valve transverse openings are made; in these openings a sliding plate is
fitted to move steam-tight. The use of the sliding plates is that when the
maiu slide valve has arrived at the end of its travel and the steam port is
fully open, the sliding plate at that end of the valve, when the port is wide
open is immediately passed across the opening, then over the port; the port
thus being very rapidly closed the, admission of steam to the cylinder is at
once cut off, and that already in the cylinder completes the stroke by expand-
ing. This arrangement of valves ensures a much more speedy cut off than
can be effected by the ordinary slide valve alone, driven as usual by eccentrics.
The motion necessary for effecting the rapid movement of the sliding plates
is effected by means of a cam on the driving or other shaft, as in the first
modification and which need not be again described.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Robertson in the Great Seal Patent Office on the 4th
December 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ROBERTSON, of Glasgow, in the County of Lanark, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of June, in the year of our Lord One
thousand eight hundred and sixty-five, in the twenty-eighth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Robertson, Her special license that I, the said John Robertson, my
executors, administrators, and assigns, or such others as I, the said John
Robertson, my executors, administrators, or 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 MACHINERY

page_text: OR APPARATUS FOR ACTUATING THE SLIDE VALVES OF MARINE ENGINES AND IN THE.
SLIDE VALVES THEREOF," upon the condition (amongst others) that I, the said:
John Robertson, 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 John Robertson, 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 Drawings, and to the letters and
figures marked thereon, that is to say :-
My said Invention relates to a certain arrangement of mechanism for
working the slide valves of marine engines.
One modification of this Invention is carried out by dispensing with the
ordinary slide valve and substituting in lieu of it two or more valves driven
by means of a cam or cams on the main or other shaft of the engines, in which
one or inore oblique grooves, are cut round the circumference. The end of a
lever passes into these grooves and as the cam revolves the lever is accordingly'
caused to vibrate. The vibrating lever being connected to upright shafts
passing into the steam chest and exhaust chest for working the slide and
exhaust valves, receives a partial rotatory movement corresponding to the
vibrations of the lever or levers, and by means of a toe or short lever on those
portions of the shafts on the interior of the steam and exhaust chests the
motion is transmitted to the valves.
And in order that my said Invention may be properly understood, I shall
now proceed more particularly to describe the mode or manner in which the
same is or may be used or carried into practical effect.
In applying this Invention to a pair of "inverted cylinder direct acting
engines," grated slide valves are used which work horizontally across the steam
ports, and the faces of which are parallel with the cylinder. These valves have
a series of small ports, through which the steam is admitted into the cylinder.
And it is preferred in this case to exhaust the steam from the cylinder
through two other ports called the exhaust ports, having similar grated slide
valves working horizontally across them, through which the steam passes in-
exhausting from cylinder to condenser. These grated valves it is preferred
to move by: a toe that works against two projections cast on the valve.
This toe is fixed-on an upright shaft which receives a vibratory motion from
a cam fixed on a separate shaft which is wrought from the main engine shaft:
'

page_text: This cam is of the style generally used to give motion to the feed apparatus
of slotting machines and other tools; that is a solid ring of metal having a
groove running round the circumference partly in an oblique direction, diverging
off the original groove into another groove which runs round the circumference
some distance and then turns off till it joins into the original groove. Advantage
is taken of this diverging groove, as the cam revolves with the engine to give
a vibrating motion to the upright shaft which works the grated valves by
means of the toe already described. This vibratory motion is conducted to
the upright.shaft through a lever fixed on the shaft, the lever being fitted
with a pulley working loose on a stud projecting into the groove of the cam,
and when the cam revolves the divergence and reunion of the grooves causes
the lever to vibrate. In the case of the cam for working steam valves, one
cam with two grooves' is preferred, one groove for working the top steam valve
through a solid shaft the other groove for working the bottom steam valve,
through a hollow shaft working loose on said solid shaft. In the case of a
cam for working exhaust valves, one cam is preferred with one groove having
one lever which is fixed to the solid shaft and which works the top exhaust
valve, working in bottom side of the cam, and having the other lever which
is fixed to the hollow shaft, and works the bottom exhaust valve working in
top side of the cam. To reverse the valves of inverted cylinder marine engines
it is preferred to do this by means of a spiral groove on the boss of the wheel
through which motion is transmitted from the engine shaft. This reverse
motion is already in. use and need not be described here..
In the annexed Sheet of Drawings Figure 1 is a sectional plan of a cylinder
having the grated valves actuated with the arrangement of cams and levers;
Figure 2 is a section of the cylinder, showing steam and exhaust ports and
valves with solid and hollow upright shaft for working them; Figure 3, is a
longitudinal elevation of the crank shaft with the small or secondary shaft
having exhaust cams attached, also showing the spiral tongue for the reversing
valves; Figure 4 is an end elevation showing steam and exhaust cams on
their relative shafts, also the vertical solid and hollow shafts for working the
valves, with lever connecting said shafts to cams.
A, A', are the exhaust ports; B, B', the steam ports, having a series of
smaller ports running parallel with the cylinder; C is the top steam valve in
which ports are formed corresponding to those in the valve seats; D, is the
toe fixed on the upright shaft E, which gives motion to the top steam valve.
The shaft E is the solid shaft herein-before described, and extends downwards
to the engine sole plate; it is geared into the groove of the cam H, by the
lever G Figure 1. C is the bottom steam valve; J is the toe fixed on the

page_text: upright hollow shaft I, and which gives motion to the bottom steam valve.
The hollow shaft I extends down to the sole plate, and is connected with the
cam H by the lever K, Figure 1. The cam H, Figure 4, is fixed on the
shaft L, which receives a revolving motion from the main shaft X, through
wheels P and N, "both of which are of the same diameter," gives the shaft L
the same number of revolutions as the shaft X, as the cam H revolves with
the shaft L and produces a vibratory motion on the upright shafts E
and I by means of levers G and K, working in diverging grooves 0, 0¹, this
vibratory motion of upright shafts E and I opens and shuts the valves C, C¹,
by means of the toes D and J. The exbaust valves being actuated in a
manner similar to that of the steam valves need not be herein more par-
ticularly referred to.
Having now described the nature of my said Invention, and the manner
in which the same may be carried into practical effect, I would observe in
conclusion that what I consider novel and original, and therefore claim as
the Invention secured to me by the herein-before in part recited Letters
Patent is,-
First, the general arrangement of mechanism for actuating the steam and
exhaust valves of marine engines as herein-before described, or any mere
modification thereof.
Second, the application of obliquely grooved cams for actuating the valves
of marine engines as herein-before described, or any mere modification thereof.
Third, the combination of a tubular and solid shaft for actuating the steam
and exhaust valves of steam engines as herein-before described.
In witness whereof, I, the said John Robertson, have hereunto set my
hand and seal, this Thirtieth day of November One thousand eight
hundred and sixty-five.
JOHN ROBERTSON. (LS.)
JOHN ROBERTSON.
L.S.