IMPROVEMENTS IN BRAKE APPARATUS FOR RAILWAY VEHICLES
Year: 1880

page_text: LETTERS PATENT to Henry Harris Lake, of the Firm of Haseltine, Lake, &
A com-
Co., Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN BRAKE APPARATUS FOR RAILWAY VEHICLES."
munication from abroad by Victor Kramer, of Innsbruck, Austria.
PROVISIONAL SPECIFICATION left by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 2nd August 1880.
HENRY HARRIS LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN BRAKE APPARATUS FOR
RAILWAY VEHICLES." [A communication from abroad by Victor Kramer, of
Innsbruck, Austria.]
The present improvements relate to continuous air brakes for railway vehicles,
that is to say, brakes worked by means of compressed air, and the improvements
consist essentially in the use of a special construction of piston and a special
arrangement of apparatus connected therewith.
The arrangement of this continuous brake is as follows:-Upon each carriage is
placed a reservoir for the compressed air, and a cylinder of the form of a double
bell, receiving the compressed air and transmitting the pressure by means of a piston
rod and levers to the brake-blocks. The double bell consists of a larger one and a
smaller one, connected at their mouths by means of an intermediate ring. The
large bell is in permanent communication with the main air-conduit, whilst the
small bell communicates with the compressed air-reservoir. In the interior of the
two bells a kind of hollow cylinder or piston is arranged, which is provided with a
rod passing through a stuffing box. The piston has different diameters corre-
sponding to the diameters of the bells between the joints, by which the bells are
connected, and between two rings are placed two diaphragms of different diameters.
Each of these two diaphragms is formed of a leather bag and an india-rubber bag
covering the same. The surface of the india-rubber bag is presented to the
compressed air, and causes the bag to be air-tight, whilst the leather bag furnishes
the resistance to the pressure. During the backward and forward motion of the
piston the diaphragms pass into the annular space, so that one part is pressed
against the sides of the bell, and the other part against the sides of the piston, thus

page_text: assuming the shape of the letter U and rolling up and down, according to the
direction of the movement; whilst one of the two diaphragms is rolling up the
other rolls down. The intermediate piece connecting the bells is in constant com-
munication with the atmosphere by means of a small hole, which is always kept
open. It is to be observed that the construction of the diaphragms as described,
that is to say, so that the bags roll up and down on two surfaces, enables them to
resist the highest pressures, as the atmospheric pressure acts on a comparatively
small space. This construction is a novelty, and not yet employed for the same
purpose and in the same manner.
From the difference of diameters of the diaphragms, combined with an inter-
mediate space communicating freely with the atmosphere, results the formation of a
differential piston, the working of which is now to be explained.
From the main air conduit the compressed air passes into the auxiliary
reservoir and simultaneously into the large bell. Before entering the reservoir the
air passes through a small valve, which closes towards the outside, so that the air
may enter the reservoir but cannot escape. The reservoir itself is in communication
with both the small bell and the large one. The pipes which serve for the
communication are provided with two cocks, one of which (the one fixed to the
small bell) is a three-way cock, whilst the other one (adapted to the large bell) is a
common cock. By means of these two cocks the guard of the train may release
the brakes. A third cock allows of completely isolating the brake of the
carriage without hindering the working of the other brakes, and by means of
two more other cocks it is possible to detach a vehicle without disturbing the
whole train.
The main air-conduit being supposed to be filled with air at a pressure of 3
atmospheres, the reservoir, the large bell, and the small bell are also filled with air
at the same pressure.
The small bell can be filled only by means of the reservoir, and the cock of the
small bell must be kept open, whilst the cock of the large bell must be kept
closed.
.
In this situation the piston-rod is completely drawn back, and consequently the
brakes are released. This is effected by the diaphragm of the large bell having a
greater diameter than the diaphragm of the small bell. As the two diaphragms are
separated by a space which communicates with the atmosphere, the diaphragm of
greater diameter must throw back the other diaphragm, and therefore with it also
the piston, as both diaphragms are fixed to the same piston rod. It is evident that
the force throwing the piston back corresponds to the difference of the surfaces of
the two diaphragms.
The brakes remain released while the tension of the air does not diminish, but
the equilibrium is destroyed as soon as the tension of the air diminishes in the main
conduit. The driver can easily regulate this tension by means of a large three-way
cock. The complete escape of the air has the greatest effect, and the brakes are
applied with the greatest force; the partial escape of air produces an inferior effect,
and the brakes are applied with a more or less moderated force, according to the
tension of the air remaining in the main conduit. The travel of the piston is then
as follows: As soon as the tension of the air is diminished in the main conduit,
the small valve of the reservoir closes, and the communication of the reservoir
with the main conduit is interrupted. Supposing a tension of 3 atmospheres to exist
in the main conduit, the same tension will exist in the reservoir and in the sinall
bell, but as the air or a part of it has escaped from the large bell and from the main
conduit, the pressure on the diaphragm in the small bell will become greater than
the counter-pressure on the diaphragm in the large bell, and the piston will move
forward with a force proportional to the difference of the tensions of the air working
on the two diaphragms, combined with the difference of the diameters of the latter.
It is evident that the greatest effect is obtained when the tension of the air in the
main conduit is equal to the tension of the atmosphere.
The duplex bell is provided with two trunnions upon which it is suspended

page_text: under the carriage frame. This mode of suspension allows the duplex bell to
oscillate on the said two trunnions, and to exactly follow the movement of the
lever on which it must act. This is a great advantage, because the oscillatory
movement reduces the wear on the stuffing box and piston rod.
In order to prevent any injury to the pipes by the oscillation of the duplex bell
I employ pieces of india-rubber pipes in proximity to the bell.
The intermediate piece or ring which connects the two bells must be in constant
communication with the atmosphere. The hole therein gives a simple and sure
means of ascertaining whether there is any leakage in the diaphragms. The
escape of air is a proof that one of the two diaphragms is injured, and by aid of the
two cocks of the bells it can be ascertained which of the diaphragms is damaged,
so that this simple means efficiently secures the good working of the brakes of a
train on its journey.
The general arrangement of the continuous brake in a completely arranged train
is as follows:-The engine, the tender, and each carriage or wagon carries an
auxiliary reservoir of air, with duplex bell as described. A pump is fixed on the
engine and furnishes the compressed air, having a tension of about 3 atmospheres.
A greater tension is not necessary, and this is to be considered a great advantage
of this Invention. The air passes from the pump into a small reservoir having a
safety valve, and thence into the main reservoir and main conduit, which conducts
it to the last carriage of the train. Behind the small reservoir is placed a large
3-way cock which is within easy reach of the guard. Behind this cock a branch
pipe of the principal conduit conducts the air to the brake of the engine.
principal reservoir, conveniently placed upon the engine, ought to have a sufficient
volume not less than half a cubic meter. It is provided with a safety valve, and
can be closed by means of a cock situated between the small reservoir and the
main reservoir.
The
The safety valves of the small reservoir and the main reservoir are to be regulated
to give way or yield at 3 atmospheres or rather less, and so prevent any undue
elevation of pressure.
The safety-valve of the small reservoir comes into action
when the principal reservoir is closed by the above mentioned cock situated
between the small reservoir and the main reservoir, that is to say, when the pump
is directly working in the main conduit. Another cock, situated between the main
reservoir and the main circuit closes the air conduit extending to the brake of
the engine when this brake is not to be put into action, as is frequently desirable.
This cock is generally open during the running of the train, but it is frequently
closed during the entrance into a station, or during the descent of inclines in order
to prevent any useless wear of the engine.
The larger 3-way cock, situated between the small reservoir and the main
conduit, allows of the total or partial escape of the compressed air according to the
greater or less power by which the brakes are to be put into action. Another
position of this cock interrupts the communication with the atmosphere and opens
the communication with the pump and the principal reservoir when the cock first
mentioned, situated between the two reservoirs, is open.
The air-conduit of the tender can be closed by means of a cock situated on the
rear end of the tender in the main conduit, and the same effeet can be obtained
for each carriage by means of cocks situated on the ends of the carriages in the
main conduit. Other cocks situated in the middle of the carriages serve for
isolating the brakes of each carriage, so that the action of the brakes may be
confined to certain carriages if desired. India-rubber pipes with suitable joints
establish the communication between the different carriages of the train.
The compressed air passes to the auxiliary reservoir and to the duplex-bells of
the brake, and the cocks hereinbefore mentioned arranged each at the middle of a
carriage are similar to the above mentioned cock which provides for completely
isolating the brake of a carriage without hindering the working of the other
brakes, and the cocks arranged at the ends of the carriages are analogous to the

page_text: cocks above mentioned, by means of which it is possible to detach a carriage
without disturbing the whole train.
It is very easy to combine existing screw brakes with this improved air brake.
For this purpose a groove is to be made in the head of the piston-rod of the bell
and another groove in the fork fixed on the rod of the screw-brake. These two
grooves are necessary because the diaphragms must remain fixed while the screw-
brake is working.
To separate a carriage from the train without affecting the other carriages it is
only necessary to close the above mentioned cocks arranged at the ends of each
carriage in the main conduit and to isolate a carriage from the action of the
brake, the cock arranged in the middle of the carriage in the main conduit is
closed. The brake is thus instantly put out of action while the brakes of the other
carriages continue their function.
It may be observed that a special leakage valve does not exist in this system.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Harris Lake in the Great Seal Patent Office on the 2nd
February 1881.
HENRY HARRIS LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN BRAKE-APPARATUS FOR
RAILWAY-VEHICLES." A communication from abroad by Victor Kramer, of
Innsbruck, Austria.
This Invention relates to a novel construction of apparatus for actuating the
brake-blocks of the rolling stock of railways, and its essential feature will be readily
understood by reference to the accompanying Drawing, in which,-
Figures 1, 3, and 5, represent in elevation, and Figures 2, 4, and 6, in plan a
locomotive, a tender, and a carriage with my improved brake apparatus applied to
the same, and
Figure 7 is an end-elevation of the carriage shewn in Figure 5.
Figure 8 is a longitudinal central section of my improved differential piston
drawn to an enlarged scale.
Figures 9 and 10 are vertical sections of modifications of the said Invention and
are hereinafter fully described:
The apparatus consists of two casings a and b of unequal size, connected
by a middle piece c, communicating with the atmosphere by a small hole or
aperture c¹.
Two pistons of unequal diameter are fixed to the piston-rod e; they are
respectively connected and made air-tight with the casing by means of cupped
leather diaphragms m and m³, covered by caoutchouc diaphragms n and n¹,
whereby they are enabled to work perfectly air-tight in their casings. For facility of

page_text: placing and removing these diaphragms they are secured between two rims fand
f held between the flanges of the casing.
On moving the pistons to and fro one diaphragm will be unfolded and distended
while the other is folded; they are thereby alternately made to bear against the
sides of the casings a and b, and against the surface of the pistons & respectively,
and in so doing they form a circular fold which presents but a small annular area
to the air-pressure, so that the diaphragm being subjected to a slight strain only can
withstand very considerable air-pressure.
The proper formation of the fold, whether in the forward or backward movement,
and the close contact between the leather and caoutchouc diaphragms are ensured
by the air-pressure itself.
The leather diaphragms m, m', give the requisite strength and those of
caoutchouc n, n, afford the necessary degree of impermeability, while at the same
time the friction of this description of packing for the cylinders is almost entirely
obviated, and it is to be particularly observed that the packing thus formed by the
diaphragms affords very considerable power of resistance which will be sufficient
for every degree of air-pressure employed in actual practice, without subjecting the
diaphragms to any excessive strain.
In Figure 8 and in Figures 9 and 10 the diaphragm of one of the two pistons is
represented as being without folds, but in practice the course of the pistons is limited
in such a manner that the fold may be formed in every position.
Figure 9 shews a modification of the above described differential piston, in which
it is arranged in two separate halves, the piston-rods in this case working without
stuffing boxes.
Figure 10 shews an arrangement wherein, as in Figure 8, the pistons are combined,
and wherein one piston has a double packing so as to form an annular space whereby
the packing gland can be dispensed with.
The letters of reference in Figures 9 and 10 indicate the same parts as those in
Figure 8.
Other modifications may be employed; for instance, the two halves may be
arranged respectively as the right and left of the brake-shaft, and act on a single
lever; in this case they would be horizontal and without stuffing boxes, or both
halves may be on the same side of the brake-shaft in vertical positions, each acting
on a separate lever, in which case they would have stuffing boxes. In this
modification, as also in that shewn in Figure 9, it is not necessary to employ casings
a and b of different diameter, but it is sufficient to make the one lever of greater
length than the other, both casings being of the same diameter.
Figures 1, 2, 3, 4, 5, 6, and 7 shew the arrangement of the differential piston
as applied to brakes. The various arrangements are shewn in these Figures only
to illustrate the adaptation of my apparatus to various vehicles, and the Drawing
will suffice without any description thereof to explain the said arrangements.
The present Invention chiefly relates to the peculiar construction of a cupped
diaphragm-packing for the pistons by which it is rendered possible to advan-
tageously employ the arrangements shewn in Figures 8, 9, and 10, for the purpose
of railway-brakes, as will appear from the following explanation :-
1. The pistons are in consequence of their peculiar packing perfectly air-tight,
while at the same time they are of simple construction and easily accessible, and
have sufficient strength to withstand any air-pressure that might be employed in
practice, and consequently the pressure on the brake-blocks remains perfectly
constant during the whole time the air-pressure acts, whereby the action of the
brakes will be very energetic and reliable.
2. The differential action is in all cases produced by two pistons affording the
following advantages, viz. :-
The action of the compressed air upon the one or the other piston is unaffected
by any possible leakage of the packing, because in all cases the escaping air passes
out to the atmosphere.
The air-tight condition of the pistons can be at once ascertained when the train

page_text: is made up, as the escape of any air shews that the packings are not in order. The
safety of working is therefore increased.
The piston-rod passing through the stuffing box may be of very small diameter,
whereby its friction is greatly diminished.
Any deficiency in respect of air-tightness in the stuffing box is without effect on
the brake-power, as it will not impair the action of the piston.
The pistons can be used without stuffing boxes; this is of particular advantage
in railway-vehicles.
As the comparatively small stuffing boxes (if such are employed) will cause but
little friction, it is possible to make the pistons with any desired difference of
diameter, which is of importance for taking off the brakes rapidly.
3. The pistons operate without any perceptible friction, from which the following
advantages arise :-
The action of the brake remains equally energetic during a long time, and
without any attention to the pistons being required.
The pistons may be of very large diameter, therefore a comparatively low air-
pressure may be employed to produce the requisite power.
The mechanism is very sensitive; this property is of particular importance
where the brakes are to be applied with moderate and accurately regulated
pressure.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,
First. In atmospheric brake-pistons, subject to air-pressure only on one side, the
use of a packing consisting of a flexible cup-shaped diaphragm covering the pressure
side of the piston, and arranged and operating as herein described with reference to
Figures 8, 9, and 10 of the Drawings.
Second. The combination of the flexible diaphragm packings with the differential
pistons, the rings, and the casings, substantially as described with reference to
Figures 8, 9, and 10 of the Drawing.
In witness whereof, I, the said Henry Harris Lake, have hereunto set my
hand and seal, this First day of February, in the year of our Lord One
thousand eight hundred and eighty one.
HENRY H. LAKE. (L.S.)