Improvements in Railway Brakes.
Year: 1894

page_text: Date of Application, 7th Apr., 1894
Complete Specification Left, 7th Jan., 1895-Accepted, 9th Feb., 1395
PROVISIONAL SPECIFICATION.
Improvements in Railway Brakes.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex, Gentleman, do hereby declare the nature of this invention (which has
been communicated to
me from abroad by François Chapsal, of 79 Rue
d'Amsterdam, Paris, in the Republic of France, Engineer,) to be as follows:-
This invention relates to improvements in automatic compressed air brakes and
has for its object to render them adjustable at will and to utilize the working
pressure in a very efficient manner.
A continuous automatic brake system working with compressed air to be efficient
in operation must be capable of reducing the speed of the train when descending
inclines and of effecting a stop at the stations without jerking or jolting by means
of a gradually increased application of the brakes.
The various systems now in use of continuous brakes working with compressed
air do not effectually accomplish this result. The object of my invention is to con-
struct an improved brake which shall have the same power as the most rapidly
acting brakes for reducing the pressure in the main pipe or conduit corresponding
to the maximum braking effect of these latter brakes and shall be adjustable from
the time at which it is put into operation to the time when it gives the maximum
braking effect.
My improved brake like most brakes operated by compressed air has a triple
valve or distributing device of any desired construction an auxiliary reservoir and
a brake cylinder, but the arrangement of the different parts of the brake and the
use of a special moderator or governor on the brake cylinder allow of a great range
of adjustability.
A piston or pistons connected to the brake gear according to the arrangement of
the latter works or work in the brake cylinder.
To an auxiliary reservoir is screwed or otherwise fixed by a strap the casing of
a triple valve or distributor which thus is in direct communication with the
auxiliary reservoir.
A tubular union of the triple valve or of the distributor communicates with a
moderator or governor by a pipe on which is arranged a blow off valve.
The moderator or governor is secured on the brake cylinder, and has for its
object to produce the adjustability of the brake through a great range of initial
pressure, and as it constitutes the most important part of my invention its con-
struction and operation will now be more fully described.
Two diaphragms of different diameters are mounted on a rod of comparatively
large diameter and formed of several parts screwed together and hollowed out for
part of the length so as to form a passage therein. One end of this rod constitutes
a check valve, and the other end is fixed to a third diaphragm whose flexible part
has an area equal to that of the smallest diaphragm of the two former diaphragms
diminished by the area of the seat of the valve. The moderator is connected at one
of its sides or ends to a main pipe or conduit by a union and a pipe, whilst the other
end is secured on the brake cylinder. A valve arranged say at the side and opening

page_text: outwardly permits of the direct escape of the air from the brake cylinder by the
triple valve or by the distributor or it may be by the discharge valve.
If the air be compressed in the main pipe or conduit, the piston of the triple
valve or of the distributor is driven to the end of its travel, the air then passes to
the principal reservoir and all communication in the direction of the brake cylinder
is stopped.
If a reduction of pressure be made in the main pipe or conduit, the piston of the
triple valve or of the distributor rises and communication between the auxiliary
reservoir and the main pipe or conduit is interrupted whilst communication between
the auxiliary reservoir and the brake cylinder is opened, but the air can then only
enter the brake cylinder by passing through the moderator.
There are two cases to be considered, first that in which the brake is applied
partially, for instance when descending an incline or when a gradually increased
application of the brake is desired for stopping at some prearranged station or the
like on the line and secondly, when a sudden stop is necessary in case of danger.
In the first case, before the brakes have been applied, the pressure of air in the
main pipe or conduit acting alone on the diaphragm of the moderator or governor,
the check valve which shuts off communication with the brake cylinder remains on
its seat. If a slight reduction of pressure be produced in the main pipe or conduit
but sufficient to set in motion the piston of the triple valve or of the distributor,
the air in the reservoir acts on the diaphragm of the moderator or governor which
has the small diameter and a superficial area as hereinbefore described the apparatus
then sinks since the pressure of the air in the auxiliary reservoir is at this moment
greater than that of the air in the main pipe or conduit and the check valve rises
leaving a passage for the air from the auxiliary reservoir. A certain amount of air
then passes at the same time both into the brake cylinder and by the central passage
in the rod carrying the check valve into the chamber formed between the large
diaphragm and one of the other diaphragms, with the result, well known with
differential pistons, that the apparatus is moved in the direction of the large
diaphragm by a force equal to the pressure of air in this chamber acting on an
area equal to the difference between the area of the large diameter diaphragm and
the flexible part of the other said diaphragm.
This force is added to that which the pressure of the air of the main pipe or
conduit exerts on the other side or fuce of the diaphragm in order to oppose the
movement in a contrary direction resulting from the pressure of air in the auxiliary
reservoir on the small diaphragm.
N
Now if the differences between the surfaces of the large diaphragm and of the
other or third diaphragm be equal to of the surface of the latter diaphragm and
we suppose that the pressure in the brake cylinder remains constant at the com-
mencement of the application of the brakes then the equation of equilibrium of the
whole apparatus, taking no account of friction, will be
8 being the reduction of pressure in the main conduit or pipe and the resulting
pressure in the brake cylinder, i.e. the pressure in the brake cylinder will then
equal N times the diminution of pressure produced in the main conduit or pipe.
Thus by giving different values to n the range of the initial pressure through
which the brake will be controlled can be made to vary as desired every reduction
of pressure in the main conduit or pipe giving a pressure equal to n times this
reduction of pressure in the brake cylinder until the pressure in the letter will be
equal to the pressure corresponding to the expansion of the air in the auxiliary
reservoir into the sum of the volumes of this reservoir and of the brake cylinder.
Let us suppose that the volume V of the auxiliary reservoir V be such that the
ratio of this volume to the volume V produced by the pistons of the brake

page_text: cylinder be equal to
maximum of pressure
5.68 as in the Westinghouse brake for example. The
corresponding to the expansion just referred to and which
P-Pa
☑
a reduction of pressure in the main conduit =
3.25
=
2
1.62 kilogrammes and the
brake will be adjustable from the time it is put into action up to its maximum
braking effect.
But we have supposed that the pressure of the air of the auxiliary reservoir was
constant during the application of the brake, whilst it varies at the commencement.
In the particular case just examined, we have seen that it passes from 4 to 3-25 kilo-
grammes. It results that the reduction of pressure in the conduit corresponding to
the maximum braking effect would be more than 162 kilogrammes and that it
would increase by the difference between the initial and the final pressure in the
auxiliary reservoir, say from 4- 3.25 kilogrammes 0.75 kilogramme, which
would give 2-37 kilogrammes. Thus it could be increased or reduced at will as
herein before explained. For n = 25 for example, the reduction of pressure
corresponding to the maximum brake effect would not be more than two kilo-
grammes.
=
The moderator or governor which has already been described may be applied
without any alteration of the apparatus to any continuous brake working with com-
pressed air with rapid action in which it is desired to avoid the complete application
of the brakes when descending an incline, or the sudden jerks so disagreeable to
travellers when stopping at stations, if the brake be not gradually applied.
When the pressure in the main conduit is restored for relieving or removing the
brakes the check valve of the moderator remains closed because the valve or the
distributor then places the small diaphragm in communication with the outside air,
but the air of the brake cylinder escapes directly by the side valve hereinbefore
referred to.
An important advantage presented by this moderator consists in the fact that
this apparatus being connected directly to the principal conduit, its working can be
interrupted or started by operating a single cock placed on the pipe leading to the
principal conduit. This cock carries an air discharge hole formed in the plug
permitting the escape of the air which is above the diaphragın of the moderator
when its working is stopped.
In this last case the air will pass directly to the brake cylinder, for during the
operation of the brakes the check valve will be always open no pressure existing
on the diaphragm in the moderator to equilibrate that of the air of the auxiliary
reservoir. This arrangement moreover permits by the operation of a stop cock of
increasing or reducing the adjustability of the brake according as the carriage is
placed in a train furnished with a brake, adjustable through a large or slight range
from its initial pressure thus avoiding the violent jolts such as occur in brakes
hitherto in use.
Dated the 7th April 1894.
JOHNSONS & WILLCOX,
Agents.

page_text: Improvements in Railway Brakes.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of this invention (which has
been communicated to me from abroad by François Chapsal of 79, Rue d'Amsterdam,
Paris, in the Republic of France, Engineer), 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 improvements in automatic compressed air brakes and
has for its object to render them adjustable at will and to utilize the working
pressure in a very efficient manner.
A continuous automatic brake system working with compressed air to be
efficient in operation must be capable of reducing the speed of the train when
descending inclines and of effecting the stopping thereof at the stations without
jerking by means of a gradually increased application of the brakes.
The various systems now in use of continuous brakes working with compressed
air do not effectually accomplish this result. The object of my invention is to
construct an improved brake which shall have the same power as the most rapidly
acting brakes for reducing the pressure in the main pipe or conduit corresponding
to the maximum braking effect of these latter brakes and shall be adjustable from
the time at which it is put into operation to the time when it gives the maximum
braking effect.
And in order that this invention may be well understood I will describe the same
with reference to the accompanying drawings.
Figure 1 of which represents in elevation the operating mechanism of an
automatic brake operated by compressed air with a moderator or governor for my
improved system.
Figure 2 is a transverse section of the same on the line A B Figure 1, aud
Figure 3 is a plan thereof.
Figure 4 is a longitudinal section drawn to a larger scale of the moderator or
governor the section being taken on the line C D Figure 5, and Figure 5 is an end
view of the said governor or moderator.
Figure 6 shews in longitudinal section also drawn to a larger scale the different
parts of the apparatus. In this figure the axis of the moderator or governor
is, for the sake of clearness, shewn as being parallel to that of the triple
valve or distributor but in practice the two axes are arranged at right angles to
each other as shewn in Figures 1 and 3. Either arrangement may however be
adopted without affecting the general working of the apparatus, but the arrange-
ment shewn in Figure 3 is preferred as being most convenient for operating the
cocks or taps.
The improved brake, like most brakes operated by compressed air, has a triple
valve or distributing device of any desired construction, an auxiliary reservoir, and
a brake cylinder, but the arrangement of the different parts of the brake and the
use of a special moderator or governor on the brake cylinder allow of a great range
of adjustability.
1 represents the brake cylinder, 3 the auxiliary reservoir and 4 the distributor.
In the brake cylinder 1 as shewn in Figure 6 are pistons 2 connected by their
rods to the brake gear. To the auxiliary reservoir 3 is screwed or otherwise
connected the triple valve or distributor 4 so as to be in direct communication
one with the other. A chamber 5 in the distributor 4 communicates by a pipe or
passage 7 with a moderator or governor 6 provided with a blow off relief valve 8.
This moderator or governor which is secured to and communicates with the
interior of the brake cylinders constitutes the most important part of this invention

page_text: as by means of this governor the initial pressure of the brake may be regulated to
any extent required within a great range.
I will now describe the construction and operation of this governor with reference
to Figures 4, 5 and 6 of the drawings.
Inside the casing 6 are two diaphragms 9 and 10 of different diameters and
to the centres of these diaphragms is connected a rod 11 of comparatively large
diameter. This rod consists of several parts screwed together and is hollowed
out for part of its length so as to form a passage therein. One end of this rod
constitutes a check valve 12 and the other end is fixed to a third diaphragm 13
the flexible part of which has an area equal to that of the smallest diaphragm 9
of the two diaphragms 9 and 10 diminished by the area of the seat of the valve 12.
This governor or moderator is connected by means of a union 14 and a pipe 15
to a main pipe or conduit 16 and is also connected to the brake cylinder 1 as
hereinbefore described. 17 is a valve opening outwardly to permit of the direct
escape of the air from the brake cylinder 1 either through the distributor or
through the discharge valve 8.
If air be compressed in the main pipe or conduit 16 the piston valve 18 of the
distributor is driven to the upper end of its travel as shewn in Fig. 6, the air then
passes to the principal reservoir and all communication in the direction of the brake
cylinder 1 is stopped.
If a reduction of pressure be made in the main pipe or conduit 16 the piston 18
of the distributor falls and communication between the auxiliary reservoir and the
brake cylinder is opened through the pipe 7, but the air can then only enter the
brake cylinder by passing through the governor 6.
There are two cases to be considered, first that in which the brake is applied
partially, for instance when descending an incline, or when a gradual increased
application of the brake is desired for stopping at some pre-arranged station or the
like on the line, and secondly, when a sudden stop is necessary in case of danger.
In the first case, before the brakes have been applied, as the pressure of air in
the main pipe or conduit acts alone on the diaphragm 13 of the governor, the
check valve 12 which shuts off communication with the brake cylinder remains on
its seat. If a slight reduction of pressure be produced in the main pipe or conduit
sufficient to set in motion the piston of the triple valve or distributor to open the
passage 7 the air in the reservoir 3 will act on the diaphragm 9 of the governor,
the rod 11 then sinks since the pressure of the air in the auxiliary reservoir 3 is at
this moment greater than that of the air in the main pipe or conduit 16 and the
check valve 12 opens leaving a passage for the air from the auxiliary reservoir 3
to the brake cylinder 1 a certain amount of air passing also by the central
passage in the rod 11, carrying the check valve 12, into the chamber formed
between the large diaphragm 10 and the diaphragm 13 of the governor, with the
result, that the rod 11 is moved in the direction of the large diaphragm by a force
equal to the pressure of air in this chamber acting on an area equal to the
difference between the area of the diaphragm 10 and the flexible part of the
diaphragm 13.
This force is added to that which the pressure of the air of the main pipe or
conduit exerts on the other side or face of the diaphragm 13 in order to oppose the
movement in a contrary direction resulting from the pressure of air in the auxiliary
reservoir on the diaphragm 9.
n
Now if the differences between the surfaces of the diaphragm 10 and of the
diaphragm 13 be equal to. of the surface of the diaphragm 13, and suppose that
the pressure in the brake cylinder to remain constant at the commencement of the
application of the brakes, then the equation of equilibrium of the whole apparatus,
taking no account of friction, will be

page_text: being the reduction of pressure in the main conduit or pipe 16 and the resulting
pressure in the brake cylinder, i.e. the pressure in the brake cylinder will then
equal n times the diminution of pressure produced in the main conduit or pipe 16.
Thus by giving different values to n the range of the initial pressure through
which the brake will be controlled can be made to vary as desired, every reduction
of pressure in the main conduit or pipe giving a pressure equal to n times this
reduction of pressure in the brake cylinder until the pressure in the latter will be
equal to the pressure corresponding to the expansion of the air in the auxiliary
reservoir into the sum of the volumes of the reservoir and of the brake cylinder.
Let us suppose that the volume (V) of the auxiliary reservoir 3 be such that the
ratio of this volume to the volume (V¹) produced by the pistons of the brake
cylinder be equal to 5-68 as in the Westinghouse brake for example, the maximuni
of pressure, corresponding to the expansion just referred to and which may be
V
P Pa
-
reduction of pressure in the main conduit
3.25
==
2
= 1.62 kilogrammes and the
brake will be adjustable from the time it is put into action up to its maximum
braking effect.
But we have supposed that the pressure of the air of the auxiliary reservoir to
be constant during the application of the brake whereas it varies at the commence-
In the particular case just examined we have seen that it passes from 4 to
3.25 kilogrammes.
ment.
It results that the reduction of pressure in the conduit corresponding to the
maximum braking effect would be more than 1-62 kilogrammes and that it would
increase by the difference between the initial and the final pressure in the auxiliary
reservoir, say, t 3.25 kilogrammes= 0.75 kilogramme which would give 2.37 kilo-
grammes. Thus it could be increased or reduced at will as hereinbefore explained.
For 25 for example the reduction of pressure corresponding to the maximum
brake effect would not be more than two kilogrammes.
-
The governor which has already been described may be applied without any
alteration of the apparatus to any continuous brake working with compressed air
with rapid action in which it is desired to avoid the complete application of the
brakes when descending an incliue, or the sudden jerks so disagreeable to travellers
when stopping at stations if the brake be not gradually applied.
When the pressure in the main conduit is restored for relieving or removing the
brakes the check valve 12 of the governor remains closed, because the valve or the
distributor then places the small diaphragm in communication with the outside air,
but the air of the brake cylinder escapes directly by the side valve hereinbefore
referred to.
An important advantage presented by this governor consists in the fact that this
apparatus being connected directly to the principal conduit, its working can be
interrupted or started by operating a single cock placed on the pipe leading to the
principal conduit. This cock carries an air discharge hole forined in the plug
permitting the escape of the air which is above the diaphragm of the governor
when its working is stopped..
In this last case the air will pass directly to the brake cylinder, for during the
operation of the brakes the check valve will be always open no pressure existing on

page_text: the diaphragm in the governor to equilibriate that of the air of the auxiliary
reservoir. This arrangement moreover permits by the operation of a stop cock of
increasing or reducing the adjustability of the brake according as the carriage is
placed in a train furnished with a brake adjustable through a large or slight range
from its initial pressure thus avoiding the violent jolts such as occur in brakes
hitherto in use.
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 :-
In connection with brakes of the kind herein before described the use of a
governing device so arranged that its working may be interrupted or started by
operating a stop cock substantially as hereinbefore described; the said governing
device operating with a triple Westinghouse valve or a distributor of any suitable
construction situated between the triple valve or the distributor and the brake cylinder
but preferably on the latter and which may be applied to compressed air brakes of
the Westinghouse type without alteration of the working parts for increasing the
adjustability and reducing the consumption of air used for operating the said
brakes substantially as herein before described and illustrated in the accompanying
drawings.
Dated this 7th day of January 1895.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.