IMPROVEMENTS IN LOCOMOTIVE STEAM ENGINES, IN PART APPLICABLE FOR RETARDING AND STOPPING RAILWAY TRAINS
Year: 1859

page_text: LETTERS PATENT to Alexander Allan, of Perth, in the County of Perth,
North Britain, Engineer, for the Invention of "IMPROVEMENTS
IN LOCOMOTIVE STEAM ENGINES, IN PART APPLICABLE FOR RETARDING AND
STOPPING RAILWAY TRAINS."
Sealed the 2nd August 1859, and dated the 4th February 1859.
PROVISIONAL SPECIFICATION left by the said Alexander Allan at the
Office of the Commissioners of Patents, with his Petition, on the
4th February 1859.
I, ALEXANDER ALLAN, of Perth, in the County of Perth, North Britain,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE.
MENTS IN LOCOMOTIVE STEAM ENGINES, IN PART APPLICABLE FOR RETARDING AND
STOPPING RAILWAY TRAINS," to be as follows, that is to say :-
This Invention comprehends improvements putting it in the power of
the engine driver or others to retard or stop a railway train with greater
facility and certainty than has hitherto been attainable, and calculated to.
give increased control over the movements of the train without subjecting
Price 8d.1

page_text: the wheels or other parts to excessive wear, such as is inseparable from
many kinds of brake in use.
One improvement consists in fitting a valve or adjustable obstructing
piece to the exhaust or blast pipe of the locomotive, such valve being
worked by means of a handle placed conveniently for being actuated. If
it is wished to retard or stop the train, this valve is closed, or partially
closed, which has the effect of making the back pressure in the cylinders
equal to the boiler pressure, and effectually obstructs the action of the
pistons, and consequently the rotation of the driving wheels. It is pre-
ferred to place the valve as far from the mouth of the blast pipe and as near
the cylinders as possible, and when the blast pipe is in two branches (uniting
or not in a single mouthpiece) a valve may be fitted to each.
The Invention further comprehends the using of the steam throttled or
obstructed, as just described, to press brake blocks upon the wheels of the
locomotive to assist in retarding the train. To this end a pipe or passage
communicating with the exhaust passages of the cylinders may be arranged
to convey the steam to a cylinder or cylinders placed in any convenient posi-
tion for the purpose, and arranged to act on the brake details. In one very
convenient and simple arrangement a small oscillating cylinder is used, such
cylinder being mounted on trunnions, formed by preference at or near the end
at which the piston rod issues, and the steam may conveniently enter the
cylinder through one or both of the trunnions. The opposite end of the
cylinder may be open, and the piston rod working through a stuffing box
at the closed end may be directly jointed upon a lever on the brake actuat-
ing shaft. This shaft is, according to one plan, placed just in front of the
leading wheels, and is made to act by short links upon brakes applied to
the fronts of these wheels. Links from levers on the opposite side of the
shaft pass to brakes applied to the backs of the driving and trailing
wheels. The brake-actuating movements may be extended by suitable
coupling arrangements to the tender or other portions of the train.
A further improvement comprehended in the Invention consists in packing
locomotive engine pistous by means of brass rings of angled section, arranged
to act in the same way as the cupped leathers of a hydraulic rain. Each ring
is cut at one point to admit of its expanding, which it does by the action of
the steam inside it. This kind of packing is peculiarly suitable for the cylinder,
by means of which the brakes are actuated according to the system herein-
before described. For the piston of this cylinder a single ring only is used,
this being expanded when the steam is acting, but contracting on the removal

page_text: of the steam pressure, so as to allow the piston to easily return to the bottom
of the cylinder, and the brake blocks to recover themselves, the latter being,
by preference, hung so as to do so by their own weight.
SPECIFICATION in pursuance of the conditions of the Letters l'atent,
filed by the said Alexander Allan in the Great Seal Patent Office on
the 3rd August 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
ALLAN, of Perth, in the County of Perth, North Britain, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of February, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Alexander Allan, Her special licence that I, the said Alexander
Allan, my executors, administrators, and assigns, or such others as 1, the
said Alexander Allan, 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
Irclaud, the Channel Islands, and Isle of Man, an Invention for "IMPROVE.
MENTS IN LOCOMOTIVE STEAM ENGINES, AND IN PART APPLICABLE FOR RETARDING
AND STOPPING RAILWAY TRAINS," upon the condition (amongst others) that i,
thesaid Alexander Allan, 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 Alexander Allan, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement in writing, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say:-
My said Invention comprehends improvemonts putting it in the power of
the engine driver or others to retard or stop a railway train with greater
-

page_text: facility and certainty than has hitherto been attainable; and which are
calculated to give increased control over the movements of the train without
subjecting the wheels or other parts to excessive wear, such as is inseparable
from many kinds of brake apparatus in use.
.
My said Invention also comprehends improvements in pistons for loco-
motive steam engines.
And in order that my said Invention may be properly understood and
carried into effect, I have delineated upon the accompanying Sheet of
explanatory Drawings certain modifications of my improvements, to which
Drawings I shall refer in the following particular description of my said
Invention, premising that the same reference letters mark the same or like
parts in all the Figures.
My said Invention consists in the first place in fitting a valve or adjustable
obstructing piece to the exhaust or blast pipe of a locomotive steam engine,
for the purpose of throttling or stopping the steam issuing from the cylinders,
and thereby retarding or stopping the motion of the pistons and driving
wheels. In combination with this arrangement provision is made for using
the steam so throttled or obstructed to press brake blocks upon the wheels of
the locomotive steam engine, to assist in retarding or stopping the train. The
steam is made to act on the brake blocks by means of a small cylinder and
piston; and the brake-actuating movements may be extended by suitable
coupling arrangements to the tender or other portions of the train.
Figure 1 on the accompanying Sheet of Drawings is a side elevation, partly
in section, of a locomotive steam engine having a modification of my improve-
ments applied to it; Figure 2 is a corresponding transverse vertical section;
and Figure 3 is a corresponding plan, partly in horizontal section. For the
convenient introduction of a throttling valve the blast pipe A is formed in two
pieces, with a slight spherical enlargement at the joint. The valve B is
mounted on a horizontal spindle C passing through the side of the blast pipe,
and through the side of the smoke-box D,outside of which last it has attached
a lever E, connected by a link F to a hand lever G conveniently disposed at
the fire-box end of the locomotive. At a part of the exhaust passage between
the throttle valve B and the valve chest, and as near the latter as possible,
there is fitted or formed a pipe or passage H, which communicates with the
bottom of a small steam cylinder I. This cylinder I is shown detached, and
asdrawn to an enlarged scale in Figure 4. The piston rod J is .connected by
means of an adjustable link K to a lever L fast on the brake shaft M, which
has fast on it levers N, acting by means of the connecting bars O upon the

page_text: hangers of the brake blocks P. These brake blocks are in this example
applied to the backs of the leading and trailing wheels Q, R. The pipe H by
which the steam enters the brake cylinder I is fitted with a cock or valve S,
the lever of which is connected to a bell-crank lever T, carried loose on the
spindle C of the throttle valve B, and connected by a link U to a lever at G.
The levers G can be moved together or separately, and in the former case the
single movement throttles the exhaust steam, and applies it to put the brake
blocks into action, thus bringing to bear on the train the combined actions
of retarded steam in the cylinders, and that of the brakes on the wheels.
This improved brake apparatus may be modified in various ways. It is
preferred to place the throttle valve as far from the mouth of the blast pipe
as convenient, and where the blast pipe is in two branches (uniting or not
in a single mouthpiece), a throttle valve may be fitted to each. More than
one steam cylinder may be provided for actuating the brakes, and where
it is desirable to save as much space as possible, the brake cylinder or
cylinders may be made to oscillate, so that its piston rod J may be con-
nected directly to the lever L of the brake shaft M. Such an oscillating
cylinder is shown in side and front elevation in Figures 5 and 6. The
trunnions V are, by preference, formed at the bottom of the cylinder, or at
the end at which the piston rod J issues, the steam pipe H communicating
with one or both of them. The steam having to act on only one side of
the piston (the under side in the examples delineated) the opposite end of
the cylinder may be open, and the piston rod may pass through a stuffing
box in the closed end, as shown, or it may pass out at the open end, and
have fixed to it a cross-head with return rods to the brake shaft lever,
thereby dispensing with the stuffing box. The brake blocks Pare repre-
sented as applied to the backs only of the leading and trailing wheels, but
additional brakes may also be applied to the fronts of these wheels.
The improvements in pistons for locomotive steam engines consist in
packing them by means of rings (by preference of brass,) of angled section,
arranged to act in the same way as the cupped leathers of a hydraulic ram.
Each ring is cut at one point to admit of its expanding, which it does by
the action of the steam inside it.
Figures 7 and 8 on the accompanying Sheet of Drawings are a face view
and a longitudinal section of one form of locomotive steam engine piston
embodying these improvements. The piston body may be of cast iron or
other metal, but it is preferred to make it of "homogeneous metal" in the
form shown. It consists of two dish-shaped disks W, formed with rims

page_text: shaped to present a groove for the flat or inner flanges of the two brass
angle section packing rings X. The piston body may be fixed on the rod J
in any of the ordinary ways, a ferrule Y being introduced between the
disks W to prevent the centres of the disks from yielding inwards. The
packing rings X are shaped so that the steam has access inside them and
between them and the rims of the body disks W, and where the rings X
are cut a tongue is inserted in the usual way to prevent the passage of
steam. The improved kind of packing is peculiarly suitable for the
cylinder I (Figures 1 to 6), by which the brakes are actuated under my
improved system. For the piston of this cylinder a single ring only is
used, this being expanded when the steam is acting, but contracting on
the removal of the steam pressure, so as to allow the piston to easily
return to the bottom of the cylinder. Figures 9, 10, and 11, on the accom-
panying Sheet of Drawings are opposite face views and section of a
modification of this single-acting piston. The body Z of the piston is
shaped to receive the angle section packing ring X, which is kept in its
place by a junk ring a; grooves or notches are formed in the rim of the
body Z, as shown, to admit the steam between the body and the packing
ring X.
".
Figures 12 and 13 are a face elevation, partly in section, and a longi-
tudinal section of another modification of my improved piston. The body
in this case consists of three pieces; two outside disks b fitting on the boss c
formed on the piston rod J, and a central flat ring d. These three pieces
are so shaped circumferentially as when put together to present separate
grooves for each of the two angle section packing rings X. The whole is
fixed together by rivets or screw bolts. In this case as in the other
examples, the steam has access between the packing rings X and the disks b,
in consequence of which separate forcing springs are dispensed with, and
the undue friction resulting from them avoided.
Having thus particularly described my said Invention, and the manner in
which the same is or may be used or carried into effect, I have to state,
that I do not restrict myself to the precise details herein-before described
or delineated, that I do not claim to have invented every separate detail
herein-before described and delineated; and that I do not claim the
throttling of the exhaust steam independently of its use to actuate brakes,
having, since the herein-before in part recited Letters Patent were applied
for, ascertained that this feature was not, as I then believed it to be, new
at that time; but that what I consider to be novel and original, and claim
as the Invention secured to me by the said Letters Patent, is,-

page_text: First, the applying of the exhaust steam of locomotive steam engines to
actuate brakes, substantially as herein-before described.
Second, the constructing of steam brake pistons and locomotive steam
engine pistons with angle section packing rings, substantially as herein-
before described.
In witness whereof, I, the said Alexander Allan, have hereunto set my
hand and seal, this First day of August, in the year of our Lord
One thousand eight hundred and fifty-nine.
ALEXANDER ALLAN. (L.S.)
0 Witness,
EDMUND HUNT, Patent Agent,
28, St. Enoch Square, Glasgow.