Im- PROVEMENTS IN CONTINUOUS BRAKES AND SIGNALLING APPARATUS FOR RAIL- WAY TRAINS
Year: 1872

page_text: LETTERS PATENT to George Pearson Renshaw, of Park Valley, in the
County of Nottingham, Civil Engineer, for the Invention of "Im-
PROVEMENTS IN CONTINUOUS BRAKES AND SIGNALLING APPARATUS FOR RAIL-
WAY TRAINS."
Sealed the 24th January 1873, and dated the 26th July 1872.
PROVISIONAL SPECIFICATION left by the said George Pearson Ren-
shaw at the Office of the Commissioners of Patents, with his
Petition, on the 26th July 1872.
I, GEORGE PEARSON RENSHAW, of Park Valley, in the County of
Nottingham, Civil Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN CONTINUOUS BRAKES AND SIGNALLING APparatus
FOR RAILWAY TRAINS," to be as follows :-
-
This Invention relates to the application of the partial vacuum pro-
duced by a steam jet supplied from the boiler of the locomotive attached.
to the train to retard or stop the motion of the several carriages by
means of communicating pipes and suitable mechanism; also to the
means of preventing the overheating of the brake blocks, when such are

page_text: composed of metal, and, in addition, to a system of enclosed tubes or
pipes applicable to intercommunication by signals between the guard,
driver, and passengers.
In carrying cut my said Invention I fix a pipe longitudinally on the
top of each and every carriage to which my system of continuous brakes
is to be applied, such arrangement of pipes being articulated and con-
nected by means of buffer joints or flexible communications between the
several carriages in such manner that a free passage for the air enclosed
within such pipes is maintained throughout the train, the said joints. or
flexible communications being sufficiently air-tight to allow of a partial
vacuum being produced, and kept within the said pipes at pleasure.
This system of pipes communicates and is in connection at the front
end with a steam jet supplied by the boiler of the locomotive, and also
with a series of small cylinders, each having a suitable piston attached to
a rod operating by means of lever gear the brake of its own carriage in
such manner that when the steam jet is turned on by means of a cock or
valve under the control of the driver, a partial vacuum is produced
within the said system of pipes and cylinders with pistons, owing to the:
enclosed air being driven out by the issuing steam, and the said pistons
are so forced into the said cylinders by the weight of the external atmos-
phere, and the connected brake mechanism is so operated as to apply the
brake blocks to the wheels to retard or stop the train. And when cast
iron or other metallic brake blocks are used I form a cavity within such
blocks, and place such cavity in connection with a cistern or reservoir
of cold water by means of flexible pipes or tubes, thereby causing a
circulation of the said water when the said blocks become heated, and
tending to keep them cool.
•
A system of automatic valves enables the brakes to be operated if a
portion of the train becomes disconnected by failure of the ordinary
couplings, and a smaller system of pipes or tubes may be carried within
the aforesaid and larger series for the purposes of intercommunication by
signals between the guard, driver, and passengers in such manner that
the joints of the two systems may be connected and disconnected at the
articulations together and at the same time.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Pearson Renshaw in the Great Seal.
Patent Office on the 25th January 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
PEARSON RENSHAW, of Park Valley, in the County of Nottingham, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her,
Letters Patent, bearing date the Twenty-sixth day of July, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said George Pearson Renshaw, Her special
licence that I, the said George Pearson Renshaw, my executors,
administrators, and assigns, or such others as I, the said George Pearson
Renshaw, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 CONTINUOUS BRAKES AND SIGNALLING APPARATUS FOR.
RAILWAY TRAINS," upon the condition (amongst others) that I, the said
George Pearson Renshaw, 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 George Pearson Renshaw, 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 thereof, reference being had to the
accompanying Sheet of Drawings, and to the figures and letters marked
thereon, that is to say :-
The object of the first part of my Invention is to utilize the force
of suction caused by a jet of steam supplied from the boiler of the
locomotive attached to a railway train, to retard or stop the motion of

page_text: the several carriages by means of suitable arrangements and mechanism
which I shall next describe (it being well known that the power
communicable by means of exhausted air is more readily transmitted
through long pipes than that of compressed air), and the second part of
my Invention relates to a signalling communication in connection with
the first.
Figure 1 of my Drawing gives a general elevation of my Invention
ás applied to the tender, brake van, and one passenger carriage of an
ordinary railway train, with the steam jet connected with the boiler
of the locomotive. It also shews that this part of my Invention consists
generally of three parts and which division I shall for facility of
explanation follow in describing the brake), namely, first, the steam
jet; secondly, the communicating pipes and their connections for
transmitting the force of suction along the train; and, thirdly, the brake
mechanism proper, by which the pressure is immediately applied to the
wheels of the several carriages. The steam jet A, Figure 1, has a pipe
opening into the boiler, and which may be closed or opened at will
by the driver or stoker, and to a greater or less extent, by means of a
cock or valve, the rod of which extends across the back of the fire-box
of the locomotive, as shown in the Drawing, having a lever at each end,
and is so easily within command of the driver or stoker who opens the
cock after shutting off the steam now no longer required to propel the
engine, and thus quickly available to retard the train by the application
of the jet. A pressure reservoir may be kept ready exhausted of air if
desired, but I consider this generally superfluous.
The jet itself may be either plain or annular, but I prefer the latter,
as shown in section in Figure 2, as giving greater effect with the same.
expenditure of steam. The pipe B surrounding the jet may be also
reduced in diameter as shown, with advantage, at a little. distance from
the orifice of the jet, and a cone may be placed inside, as shown by the
dotted lines. The pipe B may discharge or convey the effluent steam
either into the chimney of the locomotive, or terminate by a separate
orifice, such as at the top of the cab, as in Figure 1.
When made to discharge into the chimney, the jet may also serve as
a blower to keep down the smoke, and prevent its emission under the
railway stations. When the' steam jet is turned off the external air from
the atmosphere enters the pipe B, which is necessary to permit the

page_text: relaxation of the brake blocks from the wheels. But for railways
having long inclines, it may be easily arranged by fixing a cock or valve
in the pipe B, to preserve, the partial vacuum produced by the jet after
the said jet has been turned off, and so to keep the brake in action
during the will of the driver or stoker, and to hold the brake blocks
in contact with the carriage wheels without prolonged expenditure of
steam.
I shall next explain the communicating pipes and their connections,
which extend along the entire length of the train upon the tops of the
carriages, or in any other convenient situation or position. Flexible
pipes or articulating joints or buffers are provided between the several
carriages or vehicles composing the train. In the Drawing, Figure 1,
the communicating or main pipe is shown as carried outside along the
near or left hand side of the tender at the level of the framing to be
easily applied and fixed, and the joint between the engine and tender
is made by a flexible hose with unions, and a portion of the screw
threads of these last may be cut away at opposite ends of the diameter,
and the thread made coarse to save time in screwing up, as is done in
some breech-loading cannons.
In Figure 1 the connection from the tender to the guards' van is also
shown as made with a flexible hose or pipe, but this is held to the van
by a spring clip E; given in detail in Figure 3. One such clip is
affixed to the van framing at the two diagonally opposite corners, so
that the van may be run and connected with either end foremost, and
from each such corner a pipe ascends to the main through pipe
extending along the top of the van and carriages. As it is necessary
that when the connection is made at the one corner the aperture at the
other corner should be closed, and this independently of those in charge
of the train, two valves are provided at E, F, Figure 3, which are
connected by rods and levers enclosed in a casing, and by means of a
projecting stem the valves must be pushed over and the opened valve
into a recess before making the connection with the tender, by which
it will always be certain that the passage to the tender is left open, and
the opposite one closed to the external air. The main through pipe G,
Figure 1, communicates with the corresponding pipe on the passenger
carriage H by a buffer joint, which unites automatically when the
vehicles are coupled up, and the same plan is used to connect with the
other carriages of the train, and with the rear guards' brake van.

page_text: Figure 4 shows the construction of these buffer joints in detail, and
which resemble the ordinary carriage buffers in being pressed outwards
and into contact together by spiral springs, but are placed centrally to
the width of the carriages. Each buffer hangs on a partially spherical
joint H 1, kept tight by a ring or tube of india-rubber and washer I,
and the joint over the sliding part is similarly closed, the pressure of the
external air tending to close the joints, when the suction is exerted
within. The same also applies to the flanges J of the buffers, which
may be faced with india-rubber. Each buffer is free to vibrate or
oscillate laterally and vertically with the motion of the vehicles, but
before the carriages are coupled each is kept in a position suitable for
union by being suspended from a spring K, carried by the iron frame L
fixed to the carriage. The exact union for concentrality of the flanges
is also secured when the buffers come into contact by the use of a pin or
spigot M, M, on the one side of each flange, and a cone or fancet N, N,
always on the other side. Each buffer also contains a valve O, which is
automatically opened when the buffers are brought into contact, and is
closed at the end of any carriage when disconnected, and therefore so at
the extreme end of the train.
The brake apparatus proper; by which the power is applied to the s
'friction brakes, may vary much in order to suit the present construction
and arrangements of the several vehicles. For example, in applying the
same to the tenders, as these are generally made with flap or hanging
brakes pressing only on the rear. of each wheel, it may suffice to use a.
vertical or horizontal cylinder and piston so connected with the brake
levers by a slotted rod or other device that the brake may be either
worked by hand, as usual, or by suction. And so with the guards' vans
which have generally sliding brakes pressing outwards, and placed
between the wheels, it may be sufficient to connect the cylinder and
piston to a lever on the ordinary axis of the brake lever. But as the a
ordinary passenger carriages are not already usually fitted with brakes,
I prefer, where practicable, to use the self-contained mechanism shown
in Figure 5, which can be fixed by means of a few simple bolts to the
carriage frame, and subjects this to no other strain than that of support,
besides applying the blocks so as to counterbalance each other's force on 3
cach side of the axles of the carriage wheels. In detail Figure 5 shows a
cylinder (partly in section), which is bolted to the carriage framing,
and pistons P, P, connected together at R. The upper piston is made

page_text: .
to fit the cylinder accurately by means of a cup leather or other suitable
packing, which when the piston is at rest at the bottom of the cylinder,
touches in a channel of oil S, to preserve flexibility and give lubrication
to the leather. The lower piston serves as a guide, and also to exclude
grit and the external air from the oil in the channel S. The cylinder Q
communicates with the main through pipe by means of a pipe passing
through or outside the carriage, so that when a partial vacuum is
produced in the main pipe by the action of the steam jet, the
pistons P, P, are drawn upwards, and so by pulling on the connecting
links T, T, move the levers U,U, and by the intermediate connections
apply the brake blocks W, W, W, W, to the wheels of the carriage.
When the vacuum is destroyed by the admission of the external air to
the main pipe the pistons fall by their gravity, and the brake blocks are
removed from the wheels. Each block is best hung on a joint pin X at
or near its centre of gravity, and the springs Y, Y, ensure its being
always presented to the carriage wheel in a position suited for appli-
cation, and at the same time allow of the vertical play of the springs on
which the carriage rests, by the vibration or motion of the block about
the pin X, they also assist in taking the brake blocks off the wheels.
Flat or laid chains and antifriction rollers may be substituted for the
steadying levers V, V, and counterweights for the springs Y, Y;
Z, Z, are two stops, against which the levers U, U, can rest, and from
which either can pull in the event of an accidental failure of a pin or
other part in its connection with the brake block, and so allow of the
use of the other system.
The slack caused by the wear of the blocks W may be taken up by
means of nuts A¹, but as it is desirable that this should be done
automatically, especially when wooden brake blocks are used in order to
reduce and limit the stroke of the pistons P, and increase the rapidity,
smoothness of action, and efficiency of the apparatus; a means whereby
this may be done is shewn in Figure 6, where a small lever B', worked
by each main lever U, moves a ratchet wheel C³, whenever the motion
or stroke of the main levers exceeds one tooth of the ratchet wheel, as
measured by its click or pawl. A friction plate D¹, or other suitable
contrivance, prevents the return of the ratchet wheel, and thus the
screw E¹ is kept up to its work and advanced as necessary, and the
blocks placed nearer to the wheels; but a spring may be interposed to
always ensure that the blocks shall be sufficiently clear of the wheels

page_text: when the brakes are intended to be "off," this spring being then com-
pressed by the action and superior power of the steadying springs Y, Y.
When cast-iron brake blocks are used for descending long inclines,
and where these are liable to become too much heated by the excessive
friction, I cast or make such blocks hollow, if desirable, and by means of
flexible connecting pipes arranged on the principle of the ordinary water
tuyères of forges cause a circulation of cold water from a small cistern
or reservoir through the interior and cavity of the brake blocks to keep
them cool.
In order to provide for the contingency of a part of the train running
off the rails or breaking away by the severance of the couplings (which
are, however, much less probable causes of accident than that of collision
in front) a cylindrical reservoir may be fixed in the rear guard's van,
and which may be exhausted during the action of the steam jet, and so
kept by a self-acting valve unless a communication is opened between
the reservoir and the main pipes and brake apparatus of the detached
portion of the train to control or retard its motion.
The second and last part of my Invention relates to a means of.
signalling which may be applied and coupled up in connection with the
brake mains by using internal small tubes within the said mains, and
which unite by orifices or perforations in the flanges of the buffers as
shewn in Figure 7. The small internal signalling tubes may be worked
by means of exhausted or compressed air, or both, or by air of different
densities or stages of exhaustion as limited by a pressure regulator for
the purpose of communicating between the passengers and the guard or
the guards and the driver. It is not necessary that the signalling tube
should pass within the main pipe throughout the whole of the length of
the latter, but the first may be external to and protected under shelter
of the main where passing over the tops of the carriages, but the
signalling tube ought to pass inside the buffer flanges.
An air pump driven at pleasure from one of the axles of the guard's
van may serve as a supplementary or auxiliary means of maintaining
the partial vacuum in the guard's reservoir, and this pump may be
adapted to either exhaust or compress air at will, and be variable in
length of stroke by shifting a link.
The pneumatic signalling apparatus is easily arranged to operate the
present gong or whistle signals with which the trains are now fitted by

page_text: means of pistons in cylinders or by flexible diaphragms. If a partial
vacuum be kept within the signalling tube by opening a communication
with the guard's reservoir a signal may be given from a passenger to.
the guard by the destruction of such vacuum by the moving of a chain
or cord opening a valve or cock on the said passenger carriage to the
surrounding atmosphere, and the guards may communicate between.
themselves or with the driver through the same signalling tube by means
of compressed air (self-acting valves then closing the openings at the
passenger carriages to the external air, or two signalling tubes may be
used if preferred, or otherwise it may suffice to pull on the present cord
or chain to communicate between the front guard and the driver by
sounding the usual gong or whistle. But this part of my Invention.
relates only to the general employment of the signalling tubes in con-
nection with the automatically adjusting buffers, and the coupling up of
the two at the same time, since the details for producing and transmitting
the actual signal like those for indicating, from which' carriage or com-
partment the signal has been sent may be indefinitely varied at caprice,
and to suit the special requirements of cach case..
To illustrate the power of the steam jet brake, if the cylinder Q have
sixteen inches bore, and the lever arms U, U, be respectively of twenty-
one and three inches radius, giving a leverage of seven to one, and the
force of suction amounts to ten pounds avoirdupois on each square inch
of the piston's surface, the total pressure on the four brake blocks W, W,
W, W, will be more than six tons, being by calculation sufficient to stop
a carriage weighing ten tons, and running at sixty miles per hour on a
level in about the length of a furlong, varying with the weather, and for
ordinary and lesser speeds the brake power necessary to do this decreases
rapidly as the speed is less.
It will be evident that the situation of the cylinders-Q may be varied
according to circumstances, and both cylinder and piston may be made
moveable, and each operate one of the levers U, U, and also that some
of the other details may be altered in position or construction without
affecting the general principle of the design. But I have described
the parts as they would scem generally best adapted for practical
application.
Having now particularly described and ascertained the nature of my

page_text: in practice, I hereby declare that I claim the herein-described Invention
of improvements in continuous brakes and signalling apparatus for rail-
way trains, wherein the following are important points or features,
namely:-
First. The application of the partial vacuum and force of suction of a
jet of steam supplied from the locomotive boiler to the working of the
brakes of railway trains, substantially as herein-before described.
Second. The formation of connections in the main pipe by means
of spring clips and buffers, substantially as herein-before described.
Third. The mounting or hanging in the manner herein-before
described of the brake blocks with springs or counterweights, and the
use thereof for the purposes of my said Invention.
Fourth. The taking up automatically of the slack to compensate for
the wear of the brake blocks by means of a ratchet wheel and screw
worked from the main levers, substantially as herein-before described.
Fifth. The use of hollow cavities in metallic brake blocks, into which
water flows to keep the blocks from overheating, substantially as herein-
before described.
Sixth. The use of a signalling tube or tubes coupled up together with
and at the same time as the brake apparatus by means of the spring
buffers, substantially as herein-before described.
In witness whereof, I, the said George Pearson Renshaw, have
set my hand and seal, this Twenty-second day of January,
One thousand eight hundred and seventy-three.
Witness,
A. M. HALLAM,
Park Valley,
Nottingham.
GEO. P. RENSHAW. (L.S.)