Improvements in and relating to Railway Brake Apparatus.
Year: 1892

page_text: Date of Application, 30th Jan., 1892
Complete Specification Left, 12th Oct., 1892-Accepted, 19th Nov., 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by LA COMPAGNIE DE FIVES Lille, of
95, Boulevard Beaumarchais, Paris, in the Republic of France.]
Improvements in and relating to Railway Brake Apparatus.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
This invention relates to railway brake apparatus.
The railway brake apparatus heretofore generally employed operate either by
compressed air produced by means of a pump mounted upon the locomotive engine
or by a vacuum obtained by a steam ejector likewise provided on the engine. In
both systems each vehicle has a brake apparatus essentially composed of a cylinder
provided with a piston acting upon levers, and of a distributing device such as a
slide or triple valve, the arrangement of which may be varied according to the
system of brake employed, and by the operation of which the admission of air to the
piston is determined.
All the brake apparatus of the same train are fed by a general air pipe with
which they are connected through the medium of their distributors. One of the
extremities of this pipe, that in front, has an operating cock provided in
proximity to the driver, whilst the rear extremity is simply closed by means of
a stop valve.
When the driver wishes to apply the brake he opens the operating cock 50 as
to allow a certain quantity of air to escape from the general pipe into the atmo-
sphere. In this pipe is immediately produced a reduction of pressure which is
transmitted more or less rapidly over its entire length. It is this reduction of
pressure which, by setting the distributors in action, causes the admission of air into
the brake cylinder, so that the piston by its movement will apply the blocks to the
wheels of each vehicle.
It will be readily understood that if the general pipe is of very short length the
reduction of pressure obtained by the opening of the operating cock will be
rapidly transmitted without an appreciable loss in all the brake apparatus, and
that these apparatus will work almost simultaneously, but this simultaneity of
application deemed indispensable for braking under satisfactory conditions, is not
realized to the same extent when the pipe is of a comparatively great length as for
instance in the case of long goods trains having sometimes from 70 to 80 trucks.
The reduction of pressure is then produced with much greater rapidity in front than
at the rear, thus giving rise to irregularities in the application of the brake and to
more or less violent reactions in the couplings. What has been stated regarding the
application of the brakes applies also to taking off the brakes which is effected by
a reverse movement of the operating cock that is to say by re-establishing the
pressure in the general pipe, the latter being put in communication with the air
reservoir of the pump.
It is possible to ensure in the various cases which occur in the working of
railways the desirable simultaneity in applying and taking off the brake without
interfering with the rapidity of action which it is necessary to preserve in these
apparatus. The arrangement hereinafter described will enable this important result
to be obtained.
In the apparatus hitherto employed the communication between the distributor of
each brake and the general pipe is established by a pipe or orifice of constant
section, and it is for this reason that the apparatus nearest to the operating cock

page_text: are set in action before those which are further away. This inconvenience may be
obviated or to a large extent lessened by automatically retarding the action of the
first apparatus by partially closing the orifice or pipe and promoting on the contrary
the action of the second ones, the initial section of the said orifices being made
comparatively large.
On this principle is based the operation of the improved apparatus which, as
will now be understood, has for its object to ensure a passage of air which is nearly
constant whatever may be the difference of pressure in the course of the operation
between the air contained in the distributor and that in the general pipe.
The regulating device acting designed to fulfil these conditions comprises two
chambers separated by an elastic diaphragm. The upper of these chambers is in
direct communication with the distribution through a pipe, and the lower chamber
communicates with the general pipe. The two chambers are moreover in com-
munication with each other through small apertures. Upon a central rod secured to
the aforesaid diaphragm bears constantly a small fixed valve box whose lower edge,
when the brakes are taken off are opposite the maximum section of a trapezoidal
groove forming a conduit. In the lower chamber are arranged two springs which
bend under the strains acting upon the diaphragm and reacting afterwards for
causing it to return to the original position.
One of the said springs is utilized for the normal operation of the brake,
whilst the second spring is only set in action in case of a rupture in the general
pipe.
During the normal movement of the train the pressure of the air is exactly the
same in the two chambers and under these conditions the conduit presents its
greatest section for the passage of the air, but as soon as the driver in order to
apply the brake, opens the operating cock the reduction of pressure which is
produced near the front and in the lower chamber of the regulator, immediately
causes, by compressing the first spring, the descent of the diaphragm and that of
the central rod secured to it. The section of the passage in the groove is then
reduced as the length of the movement of the diaphragm increases, and as the
reduction of pressure in the pipe becomes greater. As the latter decreases from
the front to the rear of the pipe it follows that the section of the orifice will
augment proportionately in the same direction, so that the regulator placed at the
rear of the pipe will present an aperture having a maximum section, and the
regulator placed nearest to the engine will present an aperture having a minimum
section, which is necessary for obtaining an equal outlet for all the orifices
of the distributors, for considering the losses of charge in the general pipe the
speed with which the air passes through the said aperture is greatest at the
front part of the pipe and smallest at the rear part. Simultaneity of action is
thus obtained for all the brakes, in view of the fact that the forms and section
of the groove and also the power of the springs are established under suitable
conditions.
As soon as there is a tendency of the equality of pressure being re-established
upon the two surfaces of the diaphragm the spring reacts in a very short time and
finally carries back central rod with the groove to the normal position relatively to
the valve-box.
The foregoing observations would have to be repeated with regard to taking
off the brake, only in this case the partial closing of the orifice takes place during
the upward movement of the central rod, the same spring being utilized for this
operation.
I will now set forth the operation of the regulator in case damage is done to the
train to cause either the rupture of the general pipe or the uncoupling of the flexible
indiarubber pipes connecting the fixed parts of the pipe placed under the vehicles.
The reduction of pressure in the air pipe becomes very great in the case of
compressed air brakes, and the above mentioned first spring whose flexibility
must be very great for the normal operation of the brake, would be insufficient
for bearing the pressure transmitted by the diaphragm. At this moment the

page_text: second spring which is stronger than the first comes in action and permits the
diaphragm to make a supplementary movement which by further closing the orifice
maintains the simultaneity of action of the brakes, whatever part of the pipe may
have been damaged.
The second spring will not be necessary for vacuum brake apparatus, as the
reduction of pressure in the general pipe is in this case always below one
kilogramme.
The regulating device acting by partial obturation may be of various forms
according to the special application to be made of the same for each system of
brake. It may be isolated and connected to the general pipe and to the distributor
by means of pipes or combined with the distributor so as to form an integral part
of the latter.
The diaphragm made of indiarubber or any other suitable material may also vary
in form and size and be replaced by a metallic diaphragm forming a spring or by a
piston.
It is possible to dispense with the small valve box by arranging the groove
upon a rod of very small diameter which is fitted with little friction, but without
play, in a cylindrical part, the communication between the two chambers of the
obturator being, if necessary in this case either obtained by interior lateral conduits
or by an exterior pipe. The above described regulating device acting by variable
obturation may be varied in construction without departing from the nature of this
invention.
Dated this 30th day of January 1892
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Railway Brake Apparatus.
1, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 :-
This invention relates to railway brake apparatus.
The railway brake apparatus heretofore generally employed operate either by
compressed air produced by means of a pump mounted upon the locomotive engine
or by a vacuum obtained by a steam ejector likewise provided on the engine. In
both systems each vehicle has a brake apparatus essentially composed of a
cylinder provided with a piston acting upon levers and of a distributing device
such as a slide or triple valve, the arrangement of which may be varied according
to the system of brake employed and by the operation of which the admission of
air to the piston is effected.
All the brake apparatus of the same train are fed by a general air pipe or train
pipe with which they are connected through the medium of their distributors.
One of the extremities of this pipe, that in front has an operating cock provided
in proximity to the driver whilst the rear extremity, is simply closed by means
of a stop valve.
When the driver wishes to apply the brake he opens the operating cock so as to
allow a certain quantity of air to escape from the train pipe into the atmosphere.
In this pipe is immediately produced a reduction of pressure which is transmitted
more or less rapidly over its entire length. It is this reduction of pressure, which
by setting the distributors in action, causes the admission of air into the brake
cylinder, so that the piston by its movement will apply the blocks to the wheels of
each vehicle.

page_text: It will be readily understood that if the train pipe is of very short length
the reduction of pressure obtained by the opening of the operating cock will be
rapidly transmitted without an appreciable loss in all the brake apparatus and that
these apparatus will work almost simultaneously but this simultaneity of application
deemed indispensable for braking under satisfactory conditions, is not realized to
the same extent when the pipe is of a comparatively great length as for instance
in the case of long goods trains having sometimes from 70 to 80 trucks. The
reduction of pressure is then produced with much greater rapidity in front than
at the rear, thus giving rise to irregularities in the application of the brake and to
more or less violent reactions in the couplings.
What has been stated regarding the application of the brakes applies also to
taking off the brakes which is effected by a reverse movement of the operating
cock that is to say by re-establishing the pressure in the train pipe, the latter
being put in communication with the air reservoir of the pump.
It is possible to ensure in the various cases which occur in the working of
railways the desirable simultaneity in applying and taking off the brake without
interfering with the rapidity of action which it is necessary to preserve in these
apparatus. The arrangement hereinafter described will enable this important
result to be obtained.
In the accompanying drawing I have shown how my said invention may be
conveniently and advantageously carried into practice.
Figure 1 is a vertical section of my improved apparatus.
Figure 2 is a sectional plan on the line y z of Figure 1 and
Figure 3 is a modification of Figure 1.
In the apparatus hitherto employed the communication between the distributor
of each brake and the train pipe is established by a pipe or orifice of constant
section, and it is for this reason that the apparatus nearest to the operating cock
are set in action before those which are further away. This inconvenience may be
obviated or to a large extent lessened by automatically retarding the action of the
first apparatus by partially closing the orifice or pipe and promoting on the
contrary the action of the second ones, the initial section of the said orifices being
made comparatively large.
On this principle is based the operation of the improved apparatus which, as
will now be understood, has for its object to ensure a passage of air which is nearly
constant whatever may be the difference of pressure in the course of the operation
between the air contained in the distributor and that in the train pipe.
The regulating device designed to fulfil these conditions comprises two chambers
separated by an elastic diaphragm. The upper of these chambers A (see Fig. 1)
is in direct communication with the distributor through a pipe B and the lower
chamber C communicates with the train pipe. The two chambers are moreover
in conimunication with each other through small apertures D E F G H. Upon
a central rod I secured to the aforesaid diaphragm J bears constantly a small fixed
valve box K whose lower edge L, when the brakes are taken off, is opposite the
maximum section of a trapezoidal groove m, n forming an aperture or conduit H.
In the lower chamber C are arranged two springs which bend under the strains
acting upon the diaphragm and react afterwards for causing it to return to its
original position.
The small spring is utilized for the normal operation of the brake, whilst
the large spring s is only set in action in case of a rupture in the train pipe.
During the normal movement of the train the pressure of the air is exactly the
same in the two chambers A and C and under these conditions the conduit H
presents its greatest section for the passage of the air, but as soon as the driver, in
order to apply the brake, opens the operating cock the reduction of pressure which
is produced near the front and in the lower chamber C of the regulator, immediately
causes, by compressing the small spring, the descent of the diaphragm and that of
the central rod I, secured to it. The section of the passage in the groove is then
reduced as the length of the movement of the diaphragm increases, and as the

page_text: reduction of pressure in the pipe becomes greater. AS GC latter decreases ΠΟΠΗ
the front to the rear of the pipe it follows that the section of the orifice will
augment proportionately in the same direction, so that the regulator placed at the
rear of the pipe will present at H an aperture having a maximum section, and
the regulator placed nearest to the engine will present at H an aperture having a
minimum section, which is necessary for obtaining an equal outlet for all the
orifices of the distributors, for considering the losses of charge in the train pipe-
the speed with which the air passes through the said aperture H is greatest at
the front part of the pipe and smallest at the rear part. Simultaneity of action
is thus obtained for all the brakes, in view of the fact that the form and section of.
the groove and also the power of the springs are established under suitable.
conditions.
As soon as there is a tendency of the equality of pressure being re-established
upon the two surfaces of the diaphragm the spring reacts in a very short time and
finally carries back the central rod with the groove to the normal position relatively
to the valve box.
The foregoing observations would have to be repeated with regard to taking off the
brake, only in this case the partial closing of the orifice takes place during the upward
movement of the central rod I, the same spring being utilized for this operation..
I will now set forth the operation of the regulator in case damage is done to the
train to cause either the rupture of the train pipe or the uncoupling of the flexible
indiarubber pipes connecting the fixed parts of the pipe placed under the vehicles.
The reduction of pressure in the air pipe becomes very great in the case of
compressed air brakes, and the above mentioned small spring, whose flexibility
must be very great for the normal operation of the brake, would be insufficient for
bearing the pressure transmitted by the diaphragm. At this moment the large
springs which is stronger than the first comes in action and permits the diaphragm
to make a supplementary movement which by further closing the orifice maintains
the simultaneity of action of the brakes, whatever part of the pipe may have been.
damaged.
The second spring will not be necessary for vacuum brake apparatus, as,
the reduction of pressure in the train pipe is in this case always below one
kilogramme.
The regulating device acting by partial obturation may be of various forms.
according to the special application to be made of the same for each system of
brake. It may be isolated and connected to the train pipe and to the distributor
by means of pipes or combined with the distributor so as to form an integral part
of the latter.
The diaphragm made of indiarubber or any other suitable material may also
vary in form and size and be replaced by a metallic diaphragm forming a spring
or by a piston. It is possible to dispeuse with the small valve box K by arranging
the groove upon a rod of very small diameter which is fitted to work with little
friction, but without play, in a cylindrical part, the communication between the two
chambers of the obturator being, if necessary in this case either obtained by interior
lateral conduits or as shown in Figure 3 by an exterior pipe. The above
described regulating device acting by variable obturation may be modified in
construction without departing from the nature of this invention.
Having now particularly described and ascertained the nature of this inven-.
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondents, I declare that what I claim is
First. A regulator for compressed air or vacuum brakes designed to cause the
brakes on all the wheels of a train to be equally and simultaneously applied and
released characterized by the modification of the section of the air passage leading
from one chamber to the other the partial obturation being obtained either by
the aid of a rod provided with a trapezoidal groove placed opposite a fixed slide and
connected to a diaphragm or piston in which case, the two chambers communicate-

page_text: with each other through conduits provided in the central rod, or by means of a
cylindrical rod of a small diameter also provided with the trapezoidal groove
and moving with little friction in a drilled aperture serving as a guide, in which
case the communication between the two chambers of the regulator separated by
the diaphragm or the piston is obtained by an exterior pipe or lateral interior
conduits formed in the body of the apparatus.
Second. The combination of the arrangements set forth in the first claiming
clause with the herein described details, of construction and especially with the
two springs, the least powerful spring acting during the normal movement, and the
most powerful one acting only in case of a rupture of the train pipe.
Dated this 12th day of October 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.