Improvements in Brake-apparatus suitable for Railway Vehicles.
Year: 1896

page_text: Date of Application, 28th Nov., 1896-Accepted, 13th Feb., 1897
COMPLETE SPECIFICATION.
Improvements in Brake-apparatus suitable for Railway Vehicles.
I, CAMILLE DUREY, of 17 Rue Lebrun, Paris, France, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
The operation of braking consists essentially in applying brake-blocks to the
tyres of the wheels by means of rigging which is actuated by the brake-apparatus
proper, with a force that should be capable of being varied at will according to
requirements. It is thus necessary in every brake to have at disposal :-
(1) A permanent force;
(2) Gear for regulably transmitting this force to the brake-blocks.
In the majority of the brakes at present employed, this force is taken from a
single source of power extraneous to the vehicles to be braked, and as soon as this
source disappears the brake-apparatus become inoperative.
It is thus not possible to brake an isolated vehicle, and a vehicle forming part of
a group of vehicles connected to the source of power (a complete train) is completely
at the mercy of the permanence of the said source.
Now, in electro-hydraulic brake-apparatus according to this invention, on the
contrary, the moving vehicle takes the force necessary for its braking, automatically
and when requisite, from its own ris viva or momentum.
This autonomy thus enables an isolated vehicle to be braked and also ensures
the braking of a moving train irrespectively of the number of vehicles of which it
is composed.
GENERAL PRINCIPLE OF THE ELECTRO-HYDRAULIC BRAKE.
As above stated, the momentum of the vehicle constitutes the source whence
the energy necessary for braking the vehicle is taken automatically and when
required.
For this purpose, the vehicle is fitted with a small hydraulic accumulator
forming part of the brake and always maintained automatically under pressure by
the operation (which is also automatic) of parts which receive the momentum,
which move automatically when, as a result of the consumption of liquid or of
leakage, the pressure in the accumulator is no longer at the predetermined normal
maximum, and which, automatically go out of operation when the said normal
pressure is reached.
There is thus placed at the disposal of the braking a permanent hydraulic
power that is capable of acting on a brake-piston which directly actuates the
rigging.
In the normal running of the train, an electric current is employed to work
simultaneously the brakes of all the vehicles of the train. This current acts in
various ways according to its strength, which is regulated by means of a simply
manipulated switch for applying the brakes, moderating their action, and releasing
the brakes.
Braking and increasing the braking action are effected by the permanent or
momentary interruption of the current which causes a part of the liquid to pass
from the accumulator into the brake-cylinder.
The reduction of the brake-pressure and the complete release of the brakes

page_text: are produced, on the contrary, by the re-establishment of the current, which
causes a part of the liquid under pressure contained in the brake-cylinder to
return into a reservoir under atmospheric pressure, whence the accumulator is
supplied.
In the case of an isolated vehicle, mechanical means are employed in the place
of the electric current for the same purpose.
My electro-hydraulic brake thus carries out in an advantageous manner the very
complicated functions required of brakes, viz. :-
Continuity because my brake can be applied to the whole of any number of
vehicles composing one and the same train and connected together by a single
electrical controlling-device.
Simultaneous and instantaneous operation on all the vehicles, which is a result of
the electrical controlling-device and its constant readiness to operate.
Automatic action of the brake in case of interruption of the current.
Moderability by applying at will to the piston of the brake any pressure that
may be necessary, from zero up to the maximum.
CHARACTERISTIC FEATURES OF THE ELECTRO-HYDRAULIC BRAKE.
The special features of this brake are therefore :-
(1) The automatic utilization of the momentum of moving vehicles, irrespective
of the direction of such motion, when, and only when, such utilization is necessary
for the purpose of charging a bydraulic accumulator;
(2) The automatic charging, to a predetermined normal maximum pressure,
and the maintenance at the said pressure, of a hydraulic accumulator, in such a
manner as to keep a permanent hydraulic pressure at the disposal of the braking-
devices;
(3) The distribution of this hydraulic pressure to the braking-apparatus by
means of electric controlling apparatus employing a current of variable strength
regulated by a switch, for the purpose of effecting at will and instantaneously all
braking-operations;
(4) The possibility, in the absence of the electric current and by means of
mechanical devices in lieu thereof, of braking an isolated vehicle with the same
power;
(5) The faculty, by means of the said mechanical devices, of paralyzing the
action of a brake of a vehicle forming part of a train, without interfering with the
operation of the others;
(6) An internal arrangement for automatically compensating for the wear of
the brake-blocks.
DESCRIPTION OF THE ELECTRO-HYDRAULIC BRAKE.
My electro-hydraulic brake comprises two distinct parts united in one apparatus.
First part. Devices for taking the force, and for transmitting the same to a
hydraulic accumulator where the energy is stored at the normal maximum pressure,
with apparatus for controlling the automatic operation of the said devices so as to
secure the permanency of the power by means of an immediate automatic
compensation for losses of the charge of the accumulator.
Second part. Devices for utilizing this permanent power for braking-purposes
with controlling-apparatus, which latter may be worked either electrically by means
of a switch, or mechanically by special parts arranged for that purpose.
Fig. 1 of the accompanying drawings illustrates the mode of counexion between
the brake and the axle of the vehicle;
Fig. 1 shows in detail the sleeve A mounted on the axle of the vehicle;
Fig. 1 is a side elevation of the roller C and its support;
Figs. 2, 3, & 4 show longitudinal sections taken along the axis of the pump-
piston and the accumulator-piston ;

page_text: Fig. shows a cross section;
Fig. 6 illustrates the application of the brake-apparatus to a railway-vehicle and
the mode of connecting the same to the blocks of the wheels;
Figs. 7, 8, & 9 show cross sections taken along the axis of the electro magnet;
Fig. 10 illustrates diagrammatically the different phases of the operation of the
apparatus.
TAKING THE POWER.-HYDRAULIC ACCUMULATOR.-ARRANGEMENT FOR
AUTOMATIC CHARGING (Figs. 1, 2, 3, & 4).
The power-taking device consists substantially of a sleeve A made in two parts
for convenience of erection, and keyed centrally on one of the axles B of the
vehicle. It is provided with circular saw-tooth grooves in such a manner as to
constitute one element of a wedge friction-clutch (Figs. 1 & 14). The number
of the grooves of the sleeve may vary according to the nature of the metal
employed.
The other element of this clutch, situated opposite thereto and forming the
counterpart of the sleeve A, is a circular roller C also provided with grooves,
and mounted eccentrically on an axle G at the end of a connecting rod D capable
of turning about its axis of suspension E fixed to the framing of the vehicle. This
roller is weighted or balanced in such a manner that when at rest its longest radius
is never directed towards the sleeve. To the connecting rod D is fixed a rod H
ending in a multiplying lever I which, suspended from its axis F, actuates,
through a connnecting rod K, the piston L of the pump for charging the
accumulator. This arrangement enables this piston to have a longer stroke than
would be the case if the stroke were produced directly by the necessarily short
stroke or travel of the axle of the roller (Figs. 1 & 1B).
The said pump (Figs. 2, 3, 4, & 5) is single-acting and, when it is working, it
draws in liquid by way of a valve a (Fig. 5) in the free-air vessel M and sub-
sequently forces the said liquid by way of a valve b, into the cylinder of the
accumulator S behind a piston N constantly acted upon by a spring f, whose stress
determines the pressure in the accumulator and which has a constant tendency to
move the piston back up against the end of its cylinder In cold countries, the
liquid used should be a non-freezing liquid. A spring d acting upon the pump
piston L, tends to cause it to move out of its barrel, whilst a bolt R, by engaging
with its nose in a groove in the piston L (Fig. 3), counteracts the action of the
spring d and keeps the piston at the inner end of its barrel. The bolt R is
composed of two parts separated by a spring, and it is caused to engage by means
of a bolt O which slides in the cap P of the accumulator and is provided with a
spring having a tendency to cause it to move hack. The bolt O is carried forwards
when the inner end of the piston N touches its end, and, by means of the inclined
plane at its other end, raises the lower end of the bolt R and thereby compresses
the internal spring in the latter so that the nose of the bolt R, being pushed by the
said spring, will be ready to engage in the groove of the piston L when the
said groove comes in front of it during the re-entering movement of the said
piston.
A small safety-valve g placed in communication with the delivery-passage of the
pump, is set beforehand to a pressure slightly greater than the normal maximum
pressure which it is desired to reach, and it allows the liquid in excess to flow
into the reservoir M. A double-acting pump may be used in lieu of this single-
acting pump.

page_text: the pressure in the accumulator varies from the normal maximum pressure, the
said parts enter automatically into operation in the following manner :-
The piston N of the accumulator, being moved to a certain extent into its
cylinder (Fig. 4) by the action of its spring f as soon as liquid has been withdrawn
from the accumulator, ceases to bear against the bolt O, which is then moved back
by its spring so as to release the other bolt R which moves down and releases the
piston L. The latter, under the action of its spring d, moves outwards in its barrel
and draws in water behind it, carrying with it the small brake-linkwork KI HD,
and moves the roller C into contact with the sleeve A. As the latter revolves
with the axle, it carries round with it by contact, the roller C, whose eccentricity
produces a to-and-fro movement of its axis from G' to G, and consequently, also,
a to-and-fro movement of the pump-piston L-that is to say, it causes the said
pump to operate and to force liquid into the accumulator, compressing the spring f
of the accumulator-piston (Figs. 1, 2, & 4).
In practice, the ratio of the diameters of the pump-piston and the accumulator-
piston is made such that a very small number of pump-strokes will be sufficient
for charging the accumulator. When the latter has reached the predetermined
normal maximum pressure, the end of its piston N will have carried along with it
the bolt O and consequently the spring of the bolt R will have been cocked in such
a manner that as soon as in its rearward stroke the notch in the piston L comes
opposite the nose of the bolt R, the latter will become engaged and arrest the
piston (Fig. 3), and consequently the roller C will be kept out of contact with the
sleeve A.
The safety-valve g allows of the discharge to the reservoir M of the excess of
liquid when the accumulator piston N having reached the end of its stroke, the
pump-piston I. has still a certain distance to move through before its notch will
come opposite to the bolt R that serves to arrest it.
Thus there is an automatic stoppage of the parts for charging the accumulator
when the latter has reached its normal maximum pressure and there is an automatic
restarting of the said parts as soon as the accumulator-pressure has become
diminished for the purpose of restoring such pressure to the said maximum.
Thus, a part of the momentum of the moving vehicle is converted automatically
and when required, into a permanent hydraulic pressure which is kept constantly
at the disposal of the brakes, and is utilised as hereinafter described.
BRAKE-PISTON.-REGULATOR.-ARRANGEMENT
FOR DISTRIBUTING THE
LIQUID UNDER PRESSURE. ELECTRIC CONTROLLING OR OPERATING
ARRANGEMENT (Figs. 2, 3, 4, 6, 7, 8, 9, & 10).
A brake-piston U, acts upon the blocks through the medium of rigging of any
suitable arrangement, as shown in Fig. 6. Its cylinder communicates (1) with a
passage T for the supply or the discharge of liquid according to the operation of
the distributing valves; and (2) with one end of another cylinder in which moves
a regulating-piston Z behind which there acts a spring p calculated to become
compressed to a certain extent when the piston U, and, consequently, the pistou Z,
are subjected to the maximum pressure.
The passage T can communicate with the chamber S of the accumulator by
means of the orifice provided with a valve (Figs. 7, 8, & 9). It can also
communicate, by means of an orifice provided with a valve m, with the discharge-
reservoir M, which is in communication with the atmosphere and from which the
compressing pump takes its supply. The valves j and mare each connected to one
of the two armatures of an electromagnet V having two windings into which can
pass an electric current whose intensity can be made small or great at will through
the means of a switch.

page_text: Cocks or slide-valves may, if desired, be substituted for the valves j and m.
The valve j is closed by the weak or strong current and opened by a spring in
the absence of current.
The valve m is closed by a spring in the absence of current or with the weak
current; it is opened by the strong current.
Any suitable system of springs or of counterweights determines the re-entrance
of the brake-piston U into its cylinder, when it is not subjected to any pressure of
the liquid.
MANIPULATION AND OPERATION OF THE BRAKE.
As the braking consists in causing to act on the brake-piston U, as rapidly
as possible, a pressure that is more or less considerable and can vary from zero
to the maximum according to requirements, what is to be done is to cause the
brake-cylinder, at will and during the necessary time, to communicate, at one
time for applying the brakes, with the accumulator under permanent pressure, and
at another time for release, with the discharge-reservoir M.
It is to be assumed that the apparatus is filled with liquid in all the parts
that ought to contain it. This liquid should be as uncongealable as possible―
for example, a naptha, which, having at the same time the advantage of being
a lubricant for the working parts, apppears as if it ought to be employed by
preference.
It results from the arrangement of the parts herein before described, that the
simple manipulation of a switch adapted to interrupt the electric current or to
send at will a current, either weak or strong, into the electromagnet V, enables all
the operations necessary to the braking to be performed.
It will be easy to understand this from the diagram (Fig. 10), if it be observed
that the operation of the valves take place as indicated by the following table :-

page_text: (5) indicates momentary re-establishment of the strong current F°; j is then
closed and m open the brakes are being released.
(6) indicates the establishment of the weak current Fa; j and m are then closed:
there is arrest of the release and maintenance of the desired pressure.
(7) indicates positive re-establishment of the strong current F°; j is then closed
and m open: this is the position of the full release and consequently that of normal
running of the train (1).
Normal travel of the train.-Brake at rest.-The position (1) of the switch
(strong current) indicates that the valve j is closed and the valve m open. The
latter, which establishes the discharge from the brake-cylinders to the reservoir,
being open, it follows that, if through any cause whatever the valvej should
leak, there could not, notwithstanding that, be an untimely application of the
brake.
Application. The position (2) of the switch (rupture of the current) indicates
that the valve j is open and the valve m closed; there is then escape of liquid
from the accumulator S to the brake cylinders through the passage T and
consequently application of the brake. This application increases until the
communication between S and T is interrupted by closing the valve j, as in the
position (3).
Maintenance of the application at a desired pressure. The position (3) (weak
current) indicates that is closed, and in also closed, so that the pressure obtained
at this moment is maintained on the brake-piston, because there is escape neither
ou one side nor on the other.
Increase of the application.-In order to increase the application one returns
momentarily to the position (2) (rupture of the current), which opens the valve j
and closes the valve m; in order to maintain the new degree of application
obtained the position (3), with which the two valves j and m are closed, is
restored.
Maximum application.-This is obtained by the definite rupture of the current,
by means of the position (4), with which the valve; is open and the valve m
closed; the result is an equilibrium of pressure between the accumulator and
the brake-cylinder. The compression-pump being automatically put into
operation as soon as the pressure has lowered in the accumulator, will bring back
this common pressure to the regulation-maximum producing the maximum
application. This is the automatic braking in the case of ruptures of draw-gear.
Diminution of application. This is produced by a nomentary re-establishment
of the strong current, the switch being brought into the position (5) with which,
the valvej being closed and the valve m open (as with the position (1)), the liquid
can escape from the brake-cylinder to the reservoir M. The taking-off increases
until, through the re-establishment of the weak current, by the assumption of the
position (6) (like the position (3)), the two valves j and m are closed at one time,
which arrests the taking-off and maintains it at the degree obtained.
Full Release. This is obtained by the defiuite re-establishment of the current,
the switch being brought into the position (7) (like the position (1)), which,
bringing about the closing of the valve j and the opening of the valve m, puts the
brake-cylinder into constant communication with the reservoir M. We are now
brought back to the case of the normal travel of the train (brake at rest).
To recapitulate, one can, by maintaining the strong current, maintaining the
weak current, breaking the current, passing from strong current or from weak
current to rupture, and passing from strong current to weak current and vice versa,
obtain at will absolutely all the operations necessary to braking, and that with the
greatest rapidity by the simple manipulation of a switch.

page_text: BRAKING AN ISOLATED VEHICLE.
An isolated vehicle can be braked by hand without the aid of electricity.
In fact, when there is no electric current the distributing-valves are naturally in
the position that corresponds to the application of the brake (Fig. 8), and the
latter will operate as if the vehicle formed part of a train.
In order to take-off and suspend the action of the brake it is sufficient to close
the valve j and open the valve m; for this purpose, in front of the armature Y and
of the electro magnet V (Fig. 7), there is arranged small shaft r on which is
fixed a small arm t carrying a cam u; this arm passes into an opening on the rod
of the valve j, whilst the cam is opposite to the armature Y. If then, by means of
a handle or lever, the shaft r be turned to a certain extent in the clockwise sense,
the arm t will keep the valve ; closed, whilst the cam u, bearing against the
armature Y, will open the valve m. The lever or handle for operating the shaft r
being maintained in this position by any means whatever, which may be varied
according to the nature of the vehicle, the isolated vehicle will then be able to
travel freely without the aid of electricity. The vehicle can be braked anew at
will by replacing the lever or the handle into the position that leaves free the
operation of the valve j and the armature Y, for then will be opened and m closed,
which corresponds again to Fig. 8.
My electro-hydraulic brake, in consequence of the autonomy of each vehicle,.
thus renders it practicable to obtain the very important result of braking at will an
isolated vehicle without the aid of electricity and by substituting, for the action of
the latter, the simple manipulation of mechanical parts.
With the other systems of brakes that owe their power of action to a force
extraneous to the vehicle, the latter, when it is isolated and consequently deprived
of this action, is necessarily not in a condition to be braked when the employment
of its brake would be of prime importance for operations in stations, shunting,
making up trains, and the like.
RENDERING INOPERATIVE THE BRAKE OF A VEHICLE FORMING PART OF
A TRAIN.
This operation may be rendered necessary by an irregularity in the braking of a
vehicle forming part of a train. It is necessary, therefore, to paralyze the brake
of that vehicle without injury to the operation of the others. It will be sufficient
to effect the manipulation described above for releasing the brake of an isolated
vehicle (Fig. 7), by closing the valve j and opening the valve m, in order to
paralyze the operation of this brake even under the action of the electric actuating-
apparatus, without injuring in any way whatever the operation of the brakes of the
other vehicles of the train.
AUTOMATIC COMPENSATION FOR THE WEAR OF THE BRAKE-SHOES.
The electro-hydraulic brake is provided with a device adapted to compensate
automatically for the wear of the shoes by maintaining their distance from the
wheels as invariable as possible in the taken-off position, which, by reducing this
distance, enables one to apply the brake, to any degree whatever, in the shortest
time possible.

page_text: From what has been said, it will be seen that when the brake-shoes have been
completely worn away, the bolt w will have arrived at the extremity of the rack.
If, then, it he desired to replace the shoes by new shoes, it will be necessary to
return the piston U to the inner end of its cylinder and consequently to bring the
bolt w back to the beginning of the rack, as shown in Fig. 2.
For this purpose it is sufficient, after disengaging the head of the piston U from
the rigging, to cause this piston to make a half revolution about its axis, so that the
bolt w will be at a smooth portion of the cylinder, and consequently nothing will
any longer prevent the piston from moving backwards.
When this operation has been effected, all that is necessary in order to cause the
bolt to re-engage with the rack, is to give the piston another new half turn, where-
upon, after coupling the piston to the rigging all will be restored to the initial
position, shown in Fig. 2.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In brake-apparatus of the kind referred to, a hydraulic accumulator maintained
constantly and automatically at a high pressure adapted to act, at any instant, on a
brake-piston.
2. In brake-apparatus of the kind referred to in the preceding claim, the
automatic charging of the accumulator by the vis vira of the vehicle in motion.
3. Brake-apparatus comprising a brake-cylinder U, which can, at will, be put
into communication either, by means of a valve j and suitable passages, with a
chamber S in which there is permanently liquid under strong pressure, or, by means
of a valve m and suitable passages, with a reservoir M, containing liquid simply
at the atmospheric pressure, substantially as herein before described.
4. In brake-apparatus of the kind referred to in the preceding claims, the

page_text: combination of a single or double acting pump-piston L, rigging, and a coupling
adapted to be actuated by the axle B in order to force liquid from the reservoir M
into the accumulator S, so that the said accumulator may be always at the maximum
pressure, substantially as herein before described.
5. In brake-apparatus of the kind referred to in the preceding claims, a coupling
comprising a sleeve A, furnished with annular grooves, opposite to which is placed
a roller C, mounted eccentrically to its axle on one end of a connecting rod D fixed
on the frame of the vehicle, the said connecting rod being connected to the piston L
of the pump of an accumulator by means of connecting rods H and K and a lever I,
substantially as described.
6. In brake-apparatus of the kind referred to in the preceding claims, the
provision on the brake-piston of a bolt to with an inclined plane and with teeth in
engagement with a rack for the purpose of compensating automatically for the
wear of the brake-shoes, as described and shown.
7. Brake-apparatus constructed, arranged, and operating substantially as herein-
before described with reference to and shown in the accompanying drawings.
Dated this 28th day of November 1896.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.