Improvements in Electro-hydraulic Brakes for Railway Vehicles and other purposes
Year: 1898

page_text: Date of Application, 31st Dec., 1898-Accepted, 25th Mar, 1899
COMPLETE SPECIFICATION.
Improvements in Electro-hydraulic Brakes for Railway Vehicles and
other purposes,
I, CAMILLE DUREY, of 17, Rue Lebrun, Paris, in the Republio of France, Manu-
facturing 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 -
-
In my previous Patent No 27122 of November 28th, 1896, I described an
arrangement of continuous electro-hydraulic brake having a moderable action and
gripping automatically in case of breakage of couplings or damage to the parts
of the brake I indicated that the principles and essential characteristics of my
invention consisted as follows:-
1 The momentum of the moving vehicle serves to maintain automatically under
a high and constant pressure an hydraulic accumulator arranged under each
vehicle and which may be placed in communication with a brake cylinder, each
vehicle having thus by itself its own source of energy for the braking;
2. An electric distributing apparatus enabling a communication to be instan-
taneously established between the accumulator, or the reservoir supplying it, and
the brake cylinder of each vehicle composing a train This communication
allows of a more or less rapid and more or less energetic braking being produced
on the wheels of the vehicle; it enables a greater or lesser constant action to be
maintained on the tyres and this action to be instantaneously paralysed by a
return to the reservoir of the liquid admitted to the cylinder
I have introduced various improvements and modifications in the parts which
compose my apparatus as a whole (more particularly in the parts for taking the
energy from the axle and in the electric operating and mechanical parts), in the
arrangement of said parts as regards each other, said improvements rendering
the construction and mounting of the brake more simple and less expensive and
ensuring for it a quieter and easier working
The improved apparatus which forms the object of the present invention is
shown in the accompanying drawings, in which,
Figure 1 is a longitudinal section through the axis of the accumulator on the
line W W of Figure 1 showing the connection between the axle of the vehicle,
the accumulator and the pump feeding the latter.
Figure 1, a plan view of the accumulator with its reservoir and feed pump;
Figure 1, a transverse section through the suction pipe of the pump that is,
on the line 1 1b of Figure 1*:
་
Figure 1°, a transverse section through the discharge pipe of the pump, that
is, on the line 1° 1° of Figure 1*;
Figure 1, a longitudinal section of the pump on the line 115 of Figure 1*;
Figure 1º, a section plan view in detail, on the line 1d1d of Figure 1, of the
electromagnet operating the communication between the accumulator and the
brake cvlinder,
Figure 1, a detail plan view of a sleeve A for taking power arranged on the
axle B:

page_text: Figure 1', a lateral sectional elevation of a corresponding wheel C for taking
the power connected with the piston of the pump;
Figure 2 a longitudinal section through the axis of the accumulator with a
modified arrangement of the pump and the connections between the latter and the
axie for actuating automatically said pump and feeding the accumulator,
Figure 2, a transverse section of Figure 1,
Figure 3, a longitudinal section of the brake cylinder,
Figure 4, a transverse section through pipes JI which connect sand brake
cylinder respectively with the liquid reservoir M and the accumulator proper,
Figure 4, a partial horizontal section through the axis of the same pipes;
Figure 5, a diagram of the distribution of the electric current to the electio
magnets changing the accumulator and discharging the brake;
Figures 55 and 5° represent respectively three positions of the operating com-
mutator, in normal working and for the putting on and release of the brakes
Figure 618 a diagram of the whole improved biake arrangement applied to a
railway vehicle.
I
If the diagram of the whole arrangement shown in Figure 6 be considered it
will be seen that the brake is composed in principle like the electio-hydraulic
brake described in my Patent of November 28th, 1896, No 27122, of the follow-
ing parts -
1st. A brake cylinder 1 in which a piston may travel, the rod L of which piston
18 connected with the blocks 2 by any suitable rigging, said blocks bearing on the
tyres of the vehicle wheels
2nd An apparatus comprising a liquid reservoir 3 communicating with the
open air, a pump the piston ind 4 of which is operated automatically by the
devices for taking power which receive their movement from one of the axles B
of the vehicle and an accumulator combined with the reservou 3 and maintained
under a constant pressure by the liquid drawn from the reservou by the pump.
The brake cylinder 1 and the apparatus 3 are connected by two pipes I and J con-
necting respectively with the accumulator and the reservoir Communication
between the devices 1 and 3 is established or interrupted for the various move-
ments by valves operated by two electro-magnets EE receiving electric current,
the passage and interruptions of which are regulated by means of a switch or
commutator operated by the persons in charge of the train Further, as will be
seen later on in detail, this same communication between the cylinder 1 and the
device 3 may be effected mechanically or by hand duectly on each vehicle by means
of a tap X arranged on the brake cylinder
The apparatus 3 (Figures 1 and 1) is divided by a piston N having a lapping
over leather washer N into two chambers, one M of which forms the liquid reser-
voir communicating at 6 with the open air, whilst the other S is a tightly closed
accumulator The pump body 5 which is fixed to the apparatus 3 or forms one
with it communicates with the reservoir M by means of a suction passage a¹
(Figure 1 and 1º) in which a valve a (Figures 12 and 1º) is placed It also
communicates with the accumulator S by means of a pressure passage bi in which
a valve 6 is arranged On the accumulator S an electro magnet E is arranged
with a tight joint, said magnet serving for opening or closing a ball valve c for
establishing or intercepting the communication between said accumulator and a
pipe connecting with the pipe I communicating with the brake cylinder 1 A
spring is arranged round the spindle 0 of the piston N and bears at one end
on the fixed end of the evlinder 3 and at the other end on the interior face of
the piston N which forms the movable end of the accumulator When the various
parts occupy the position shown in Figure 1 the sping fis completely expanded,
and the liquid of the accumulator having passed into the brake cylinder, the
piston N is at the end of its course When the valve c 18 closed, the pump 5
compressing the liquid in the chamber S causes the piston N to retreat into the
interior of the evlinder 3 and the spring f is thus compressed Its tension 14
calculated to correspond to the working pressure which it is desired to attain in

page_text: the accumulator. In order that this pressure may never be exceeded even in case
of the disengaging gear breaking or ceasing to act, a safety hole t is arranged at
some suitable point for limiting the recoil of the piston N Immediately the lip
of the leather or washer NI passes this hole, communication is established, by the
said hole t and the passage, between the chamber S aud the reservon M
This
very simple anlangement dispensing with any safety valve, forms one of the
improvements introduced in this brake
Figures 1, 1, 1, 1 represent the first method of connection between the
pump, the axle and the accumulator The devices for taking the power consist
essentially of a sleeve A (Figures 1 and 1') made in two parts connected by
bolts in order to facilitate mounting, keyed and centered on one of the axles B.
Said sleeve on its external surface has grooves or funrows A¹ expanding at its
ends into eccentric grooves A³ The cylinder 3 is mounted under the vehicle in
such a way that its longitudinal axis is normal with the axle B A looped or
sturup shaped aim D of a bell crank lever DD' pivotted at D* on a bracket D
cast in one piece with the cylinder 3 canes a spindle G parallel with the axle
and placed in front of same A wheel C (Figure 1) is loosely mounted on said
spindle and is maintained normally at the centre by means of two opposed
springs CC
In this position the wheel C is facing the centre of the sleeve A
the width of which corresponds practically to the recess or loop in the lever D
The aim of the lever terminates in a fork (Figure 1) in which 18 pivotted
the rod 4 of the piston of the pump, and the aim is prolonged on the other side
of the pivot D2 by a catch finger or heel H Normally a spring or counter weight
(which is not shown) tends to constantly return the wheel C into contact with
the sleeve A The guide 1od O of the piston N is prolonged beyond the cylin-
der 3 and carries an aim O' at the end of which a 10d P 18 hinged, the other end
of said 1od P being pivoted to a lever Pi keyed on a spindle carried by the
cylinder On the same spindle and in the plane of the stop II, a bolt R 18
keved, which normally when the accumulator is charged bears on the stop H and
thus holds the roller R away from the sleeve A The parts occupy the position
indicated in dotted lines in Figure 1.
When the pressure in the accumulator from any cause such as the putting on
of the brake, ceases to be the regular maximum pressure, the parts for taking
the power commence to operate automatically in order to actuate the pump In
fact the spring f expands and pushes the piston N towards the chamber S, the
1od O draws the rod P, lever P₁ and bolt R, the stop H is released and the piston
of the pump descends drawn by a counter weight or spring, the levers D1 and
wheel then occupy the position shown in full lines in Figure 1 Contact is
then made between the sleeve A and wheel C, and this latter is drawn laterally
over the groove of the sleeve to one or other eccentric A according to the duee-
tion of rotation of the axle, the corresponding spring C or C being compressed
Owing to the alternating movement thus communicated to the piston rod 4 of the
pump 5 the liquid of the reservoir M 19 forced back into the chamber S, and the
spring is thus again compressed by the piston N which recoils up to the limit
of position determined by the engagement of the bolt R with the stop H. The
connection between the iod P and the aim O' is made by means of an elastic
(flexible) piece such as a spring P in order to avoid any sudden engagement.
This engagement of the bolt R with the stop II is produced at the moment when
the axes of the wheel C and the axle B are farthest apart, and as the eccen-
tric A continues to revolve, it moves away from the wheel C which becomes
free and is returned to its normal position of repose by the spring C or C It
18 easy in practice to determine the proportion of the diameters of the pistons N
in such a way that a very few strokes of the pump piston suffice for charging the
accumulator The principle of the arrangement just described is thus the same
as that described in my previous patent.
Figures 2 and 2 represent a different mode of taking the power from the
axle and of connection between the latter, the accumulator and the pump. In

page_text: this case an eccentric A 18 keyed on the axle B and has an automatic lubrication,
and is made in two parts to facilitate its mounting This eccentric by its strap
and rod A communicates a continuous reciprocatory movement to the piston
rod 4 of the pump by means of a bell crank lever D D. The automatic changing
of the accumulator ceases (when the regulation pressure is attained therein)
owing to the rising of the suction valve which is produced in the following way.
In the part of the cylinder 3 which forms the reservoir M a shaft H¹ is
arranged transversely, said shaft being prolonged to the exterior. Two levers, an
interior one and an external one m are keyed on said shaft. In the fork of the
lever a pin h¹ is mounted on which a finger is arranged to turn. The free
end of the external lever m is arranged opposite a flexible diaphragm p forming
a movable bottom to the pump under the suction valve. The diaphragm has in
its centre a metallic piece p (Figure 2) for striking against the lever m and
valve a.
So long as the accumulator has not attained its maximum regulation
pressure, the suction valve a resting normally on its seat and the pump being
actuated continuously, its piston forces liquid regularly into the accumulatoi.
The piston Niecoils and strikes against the piece at the precise moment when
the maximum regulation pressure is attained This piece produces the rota-
tion of the shaft H' and the lifting of the suction valve, that is to say it arrests
the action of the compressing pump
As soon as the piston N advances in consequence of loss of liquid by the accu-
mulator, the stop piece is released and the suction valve drops on its sent and
the pump again acte in order to recharge the accumulator to its regulation
maximum pressure The accumulator is therefore charged automatically whilst the
vehicle is travelling. It will be noted that the arrangement of cylinder 3 18 the
same as in the example shown in Figure 1 and the safety hole t has the same
functions. It is evident that the lifting of the suction valve when the piston N
has reached a certain position corresponding to the regulation maximum pressure
may, instead of being produced by the internal organs, be produced by any other
suitable external arrangement producing the same result.
The
The brake cylinder is shown in detail in Figures 3, 4 and 4* It 18 com-
posed of a cylindrically bored body F in which a piston of peculiar construction
may move
The head K which has a cup leather or washer K' on the face which
receives the action of the liquid 18 also provided with a spur oi stud k travelling
in a groove in a sleeve K at the end of which a rod L is fixed to which the
rigging is connected.
A spring which tenda constantly to maintain the two
ends and L of the brake piston in the relative position which they occupy in
the figure 18 arranged in the interior of the sleeve K. Under the pressure of the
Liquid, the piston K, whilst compressing the spring r may continue to receive a
displacement in the direction of the arrow when the part L is stopped
piston by means of its washer K³ divides the cylinder into two chambers, one
of which M full of liquid at the pressure of the atmosphere constantly com-
municates by a passage m (Figures 4 and 4) and a pipe J with the open air
reservoir M of the cylinder 3, the other chamber S¹ communicates by a pine
or passage with the casing of a tap X and by a passage with a chamber S
full of liquid at atmospheric pressure. This latter chamber communicates itself
by means of passages, and with the return pipe J to the reservoir M The
assage is closed at its lower part when the valve c 18 pressed on its seat
opening of the valve is effected by passing current into the electro-magnet E
The tap X 18 bored with two passages r¹ and which according to the position
given to the tap allow the passages and consequently the chamber S¹ to com-
municate with one or other of the pipes I and J
The
When the tap X is in the position shown in Figure 4 communication is estab
lished or closed between the chamber S of the accumulator and the chamber S¹
of the brake cylinder, according as the valve c operated by the electro-magnet E,
Figure 1, 18 opened or closed. On the other hand the communication between
Baid chamber 8¹ by means of the pipe J with the reservoir M, which communi-

page_text: cates with the atmosphere, is established or closed according as the valve c'
operated by the electio-magnet E¹ is opened or closed
The electro magnets E and El comprise an armature pivoted at and
carrying a finger E3 which in the electro magnet E is arranged to press the
valve on its seat and isolate the chamber S when the curent passes into the
coil. In the electromagnet E¹ however the finger E³ 18 arranged to allow the
valve o to rise off its seat under the influence of the attraction that the core
exercises on the armature when the curent passes in the coil, the valvo being
normally maintained on its seat by a spring d (the tension of which is adjust-
able), when the current is interrupted
Figure 5 1 a diagram of the distribution of the current to the electro
magnets E and E. S and S are two suitable sources of electricity (such as
batteries, dynamos or the like) the terminals of which are connected with the
blocks plp of a single switch placed on the two circuits and operated by
the diver. Electro magnets E are inserted in the circuit of the source S and
electro magnets E in the circuit of the source Sb
A simple examination of Figures 5 to 5' will show that when the handle of the
switch is in the position shown in Figure 5º, current will flow through the electro
magnets E and E¹ whereby the valves c are closed (closing the communication
between the accumulators and the brakes) the valves o are opened (placing the
chamber S of the brake cylinder in communication with the reservoir M), the
brake is completely released. If for any reason the valve e fits badly on its seat,
it could not produce any irregular or excessive application of the brake
In the position shown by Figure 5" the current is cut off both in the electro-
magnet E and also in the electro magnets E', the valve c 18 open and the valve c¹
closed and the brakes are applied. In fact the liquid flows freely by the pipe
from the accumulator S into the chamber S of the brake cylinder
The pies-
sure of the brake is progressive, it increases until the valve c 18 again closed by
the current being re-established in the electro magnet E without re-establishing
the current in the discharge electro magnet E¹.
The handle of the switch then has the position shown in Figure 5*, the braking
is maintained with the intensity attained the moment the curient is re-established
in the electro magnet E By maintaining for sufficient length of time the posi-
tion 5b it 18 evident the maximum braking may be obtained
It is evident that an increase of the braking is caused by instantaneously
changing from the position 5* to the position 5b followed by a return to the
position 5, whilst a diminution of the braking is obtained by a momentary
changing from the position 5* to the position 5 followed by a return to the
position 5 which may be called the statu quo position.
To sum up, the three positions shown in Figures 5*, 5". 5 of the switch are thus
sufficient for obtaining as desired all the operations necessary for applying or
releasing the brake and with the greatest rapidity The pressure is transmitted to
the brake blocks or shoes in a very perfect manner owing to the action of the iegu-
lating piston K Said piston allows liquid from the accumulator to be received
and discharged to the reservoir at the same time that it communicates to the
brake rod L the pressure resulting fram the degree of compression of its sping T
without the contact of the brake blocks with the wheels ceasing to be main-
tained, in fact the brake rod L does not re-enter its cylinder so long as it is
subjected to an appreciable pressure transmitted to the spring by the piston K
A single or separate vehicle may be braked by hand without the use of elec-
tricity.
In fact, the electric supply being shut off, the valves cc will naturally be in
the position corresponding to the application of the brake (valve c open, valve c¹
closed) In order to effect the release of the brakes and suspend their action it
is sufficient when the tap X is in the position shown in Figure 4, to cause the tap to
turn 180°. It necessarily results therefrom that although the valve c 18 oren,
the solid part of the tap will correspond with the supply pipe I and the cham-

page_text: ber S¹ of the brake cylinder will no longer receive liquid from the accumulator
and as said chamber then communicates by the tap X with the pipe J the liquid
admitted returns to the reservoir. The return of the tap X to the position shown
in Figure 4 will re-establish (if the vehicle be moving) the application of the
brake. Thus by a simple manipulation of the tap X the biake may be put on oi
off at will It may also if desired be made to assume an intermediate position
corresponding to the "statu quo" (position 3 of the switch) The same tap when
maintained in a position for taking off the brake, allows of the brake of a vehicle
forming part of a train to be rendered inactive, the working of the brake pre-
serving none the less its continuity from one end of the train to the other
In order to ensure an automatic compensation for the wearing away of the
brake shoes or blocks a ring in two parts is aanged on the cylindrical
sleeve K2 of the brake piston, said ung being fitted to said sleeve and pressed
thereon by means of a spring y The ring can only thus slip with difficulty
over the surface of the piston, nevertheless the tension of the spring is such that
it cannot prevent the piston L emerging but it prevents its return into the
cylinder beyond the stop shoulder y against which the ring catches
The ring is thus drawn with the brake piston up to its fiont and real limits y¹ ª
corresponding to the normal distance of the brake blocks from the wheels when the
biake 18 off Owing to this arrangement the distance of the biake blocks from the
wheels when the brake 18 off is maintained constant and equal to a minimum
fixed when the blocks are mounted In fact if by reason of wear this distance
be increased, the piston L at the first action of the brake will continue its course
until the blocks are in contact with the wheels, whilst the ring at first carried
with it is stopped at the front stop y³. There will therefore be a relative recoil
movement of the ring corresponding to the wear of the brake shoes. The result
is that the following return movement of the piston L into its cylinder will be
diminished by the same quantity, seeing that this etuin movement 18 limited and
determined by the rear stop y of the ring w This arrangement has in addition
the great advantage of placing all the brake blocks or shoes at their normal
distance from the wheels at the releasing which follows the first action of the brake,
where this distance of separation has not been previously regulated. The replace-
ment of worn blocks or shoes is easily done by pushing the brake piston KL
to the end of the cylinder, thus forcing the ring to slide towards the part L
of the piston,
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1 In an electro-hydraulic brake such as described in my previous Patent
No. 27122 of November 28th 1896, an arrangement for taking the power from
the axle or for the automatic throwing in or out of action of the pump which
feeds the accumulator, characterised by a bell crank lever (DD) being hinged
to the piston rod of the pump, one of the arms (D) of which lever forms a sup-
port for the wheel (C) for taking the power, which wheel has both a longitudinal
and rotary movement on engaging with a sleeve (A) fixed on the axle, whilst
the other arm (D¹) of the lever is prolonged by a finger or heel (H) which 18
engaged for the stoppage or released for the taking of power by a pivotting
finger which 18 adapted to turn when the piston (O N) of the accumulator
moves, substantially as herein before described with reference to Fioules 1, 1,
1º, and 1 of the accompanying drawings
2 In an electro-hydraulic brake of the kind described, an arrangement for
taking the power from the axle or for the automatic throwing in or out of action
of the pump which feeds the accumulator, characterised by an eccentric (A³ A*)
being mounted on the axle and connected by means of a bell crank lever (DD¹)
to the piston rod (4) of the pump which remains in continuous movement, the
cessation of action of the pump being obtained by the raising of the suction