IMPROVEMENTS IN OPERATING PISTON VALVES OF STEAM ENGINES
Year: 1868

page_text: LETTERS PATENT to Charles John Galloway, of the City of Manchester,
in the County of Lancaster, Engineer, and Charles Herbert Holt,
of the same Place, Engineer, for the Invention of "IMPROVEMENTS IN
OPERATING PISTON VALVES OF STEAM ENGINES."
Sealed the 12th January 1869, and dated the 14th July 1868.
PROVISIONAL SPECIFICATION left by the said Charles John Galloway
and Charles Herbert Holt at the Office of the Commissioners of
Patents, with their Petition, on the 14th July 1868.
We, CHARLES JOHN GALLOWAY, of the City of Manchester, in the
County of Lancaster, Engineer, and CHARLES HERBERT HOLT, of the
same Place, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN OPERATING PISTON VALVES OF STEAM ENGINES," to be as
follows:-
The improvements have for their object to facilitate the use of a
variable cut-off of the steam when using piston valves to regulate the
passage of steam to the cylinder of steam engines. For this purpose the
piston valves are each formed with horns or projections, which are in
width a little in excess of the space between them sufficient for the

page_text: lap of the ports, and the horns of one piston valve are opposite the
spaces of the other. Both piston valves are capable of rotation with
their shaft, which whilst it is capable of sliding endwise, as actuated by
the eccentric or otherwise, is also formed in part of a hexagonal or other
sultable figure, where it passes through the boss of a tooth wheel, by
which it is caused to rotate with that wheel. This tooth wheel is taken
into by the teeth of another wheel, which we prefer to be of half the
diameter of the former; upon the axis of this second wheel is applied
a catch wheel or arms adapted to be caught and successively moved for
the rotation of the valves by a stud on a plate affixed to another axis,
and this other axis also carries a mitre wheel, which with another mitre
wheel affixed to another axis receiving constant motion are both simul-
taneously taken into by the teeth of an intermediate mitre wheel, which
is capable of rotation on a rocking arm actuated by the governor, so that
whilst a constant rotary motion is being given to the piston valves the
time or speed in such rotation is varied by the action of the governor to
regulate the cut-off,
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles John Galloway and Charles Herbert Holt
in the Great Seal Patent Office on the 14th January 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, CHARLES
JOHN GALLOWAY, of the City of Manchester, in the County of Lancaster,
Engineer, and CHARLES HERBERT HOLT, of the same Place, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of July, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said Charles John Galloway and Charles Herbert
Holt, Her special licence that we, the said Charles John Galloway and
Charles Herbert Holt, our executors, administrators, and assigns, or
such others as we, the said Charles John Galloway and Charles Herbert
Holt, our 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,

page_text: exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN OPERATING PISTON VALVES OF STEAM ENGINES," upon the
condition (amongst others) that we, the said Charles John Galloway and
Charles Herbert Holt, our executors or administrators, by an instrument
in writing under our, 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 we, the said Charles John Galloway and Charles
Herbert Holt, 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) :-
The improvements have for their object to facilitate the use of a
variable cut-off of the steam when using piston valves to regulate the
passage of steam to the cylinders of steam engines. For this purpose the
piston valves are each formed with horns or projections, which are in
width a little in excess of the space between them sufficient for the lap
of the ports and the horns, and consequently the spaces or ports of one
piston valve are opposite those of the other. The ports of one valve seat
are opposite the intermediate parts of the other valve seat. Both piston
valves are capable of rotation with their shaft, which whilst it is capable
of sliding endwise as actuated by the eccentric or otherwise is also
formed in part of a hexagonal or other suitable figure where it passes
through the boss of a tooth wheel by which it is caused to rotate with
that wheel. This tooth wheel is taken into by the teeth of another
wheel, which we prefer to be of half the diameter of the former; upon
the axis of this second wheel is applied a catch, or star wheel, or arms
adapted to be caught and successively moved for the rotation of the
valves by a stud on a plate affixed to another axis, and this other axis
also carries a mitre wheel which with another mitre wheel affixed to
another axis receiving constant motion are both simultaneously taken
into by the teeth of an intermediate mitre wheel, which is capable of
rotation on a rocking arm actuated by the governor, so that whilst a
constant rotary motion is being given to the piston valves, the time or

page_text: speed in such rotation is varied by the action of the governor to regulate
the cut-off.
But that the Invention may be fully understood we will, by the aid
of the accompanying Drawings, proceed to describe means pursued by
us in carrying the same into effect.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows an arrangement of parts adapted to carry the Invention
into effect; Figure 2 shows parts separately drawn to a larger scale than
Figure 1; Figures 3 and 4 are sectional end views of parts drawn to the
scale of Figure 2. In each of the Figures of the Drawings the same
letters indicate corresponding parts wherever they occur.
a, a, are the pistons; a¹, the horns thereof; and a³ the spaces or ports
between the horns a¹. The ports of one valve seat are opposite the inter-
mediate or closed parts of the other valve seat, whilst the spaces or ports
of one valve a are opposite or in the same line with those of the other.
The pistons a, a, are affixed to the shaft b, so as to be capable of rotation
with that shaft as rotary motion is imparted to it. Endway motion is
imparted to the shaft 6, and consequently to the valves a, a, by means of
the eccentric c on the crank axis c¹, or it may be by other suitable means
through the connecting rod d, the other end of which embraces a stud e,
which is capable of sliding in a slot formed for it in the stationary guide f,
and is formed to receive the outer end of the rod b, which at that part is
provided with collars and set nuts b', so that it may be moved endways
with any to-and-fro motion of the stud e, and yet be free to revolve
therein. In order that rotary motion may be given to the valves a, a,
the shaft b is formed at 62 into sexagonal or other suitable form to slide
endways through a corresponding form in the boss of the tooth wheel g,
and according to the arrangement shown this progressive rotary motion
at the times and to the extent desired is obtained from the bevelled
toothed wheel h on the crank shaft c¹, the teeth of which take into the
teeth of the bevelled tooth wheel i affixed on one end of the shaft,
which is supported so as to be capable of revolving in stationary bear-
ings 2, 3, and has affixed on its other end the bevelled pinion, which
by means of the bevelled pinion j is capable of giving motion to the
bevelled pinion ke affixed on one end of the shaft or axis k, which is
supported with capability of revolving in stationary bearings k³, k, and
has connected to it by spring clutch connection the face plate 1, having
a stud projecting from it in position to act upon the teeth of the star

page_text: wheel m, and in the rotation of the face plate to give step-by-step rotary
motion to that star wheel. This star wheel m is affixed to one end of a
shaft m', which is supported in stationary bearings m³, m³, and has affixed
upon it the pinion m³, the teeth of which take into the teeth of the
wheel g; thus may rotary motion be communicated to the valves; but
that the extent of this motion may be controlled by the "governor" the
intermediate bevelled pinion j is supported to revolve on an arm j", which
is formed with lugs to turn in stationary fixed bearings ♬ coincident
with the centres of the axes i' and ', whilst the outer end of this arm
is by pin joint j and suitable connecting rod linked to the governor to be
operated by it, so that as the governor rises or falls the other end j* of the
arm is actuated in one or the other direction, turning the pinions , j,
and
partially round, thereby altering the relative movements of the
pinions and k, and by causing the stud in the plate to act sooner or
later on a tooth of the star wheel m varying the cut-off effected by the
valves a, a; n and o are stops which simply hold the star wheel m in
position.
Having thus described our improvements, and means which we adopt
in carrying the same into effect, we would have it understood that we do
not confine ourselves to the precise details shown and described, as these
may be varied without departing from the peculiar character of our
Invention; but what we claim is, the arranging and combining parts
whereby piston valves may be caused to revolve so as to regulate the
passage of steam to the cylinder by a variable cut-off, substantially as
described.
In witness whereof, we, the said Charles John Galloway and Charles
Herbert Holt, have hereunto set our hands and seals, this Twelvth
day of January, in the year of our Lord One thousand eight
hundred and sixty-nine.
CHARLES J. GALLOWAY. (L.S.)
CHA. H. HOLT.
(L.S.)