Improvements in Fluid Pressure Automatic Brake Mechanism for Railway Trains.
Year: 1895

page_text: Date of Application, 23rd Apr., 1895-Accepted, 15th June, 1895
COMPLETE SPECIFICATION.
Improvements in Fluid Pressure Automatic Brake Mechanism for
Railway Trains.
I, GEORGE WESTINGHOUSE Junior, of Pittsburg, Pennsylvania, United States
of America, 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 object of my invention is to provide means whereby the brakes on railway
trains may be applied with great force and rapidity and practically simultaneously
on all the care of a train. To this end, my invention, generally stated, consists in
certain novel devices and their combination with an automatic fluid pressure brake
system whereby a rapid reduction of train pipe pressure and a consequentially
rapid powerful and nearly simultaneous application of the brakes may be obtained.
The improvement claimed is hereinafter fully set forth.
My invention is adapted to be operated in connection with an ordinary triple
valve, that is, a valve controlling the passage of air from the train pipe to the
auxiliary reservoir, from the auxiliary reservoir to the brake cylinder, and 'from
the brake cylinder to the atmosphere; the triple valve being, connected, as, usual
in an automatic brake system, with an auxiliary reservoir, and, by means of a line
of pipe with the engineer's valve. My improvement applied in an ordinary
automatic system provides a quick acting brake system which operates to produce
substantially the same results as are obtained by the employment of the quick
acting devices shewn and described in the Specifications No. 4676 of 1887
and No. 275 of 1888.
1
A car fitted with my present improvement may be operated in connection, with
other cars in a train having any of the above quick action devices, or which, are
fitted with the ordinary triple valve without quick action devices.
In the accompanying drawings
↓
Figure 1. is a plan or top view of the fluid pressure brake apparatus of a car with
my improvement forming a part thereof;
Fig. 2, a central longitudinal section through my improvement, and, a portion of
the brake cylinder.
Fig. 3, a transverse section, at the line of Fig. 2;
+
Fig. 4, a longitudinal central section of a modification of my improvement ;
Fig. 5 a transverse section at the line y. y. of Fig. 4.;
"
'
Figs. 6 and 7 longitudinal central sections of modifications in which I employ¡a
lever for opening the valve...
In the brake apparatus illustrated, the train pipe 1, is connected, as usual in
automatic brake systems, by the branch pipe 2, with the triple valve 3, and through
the triple valve with the auxiliary reservoir, 4; the triple valve being connected
by the pipe 5, with the brake cylinder 6. These are the usual connections of an
automatic brake apparatus in which, a plain triple valve is employed.
As shewn in Figs. 1, 2 and 4 my quick acting device is arranged within a casing 7
formed, on the head, 8, of the brake cylinder 6 and the casing 7 is connected with
the train pipe by a branch pipe 9 which is attached to the outer end of a
passage 10 in the casing..
i.
Within the brake cylinder 6, is the usual brake piston 11, the piston rod 12, of
which, is connected to the mechanical devices for moving the brake shoes.
Attached to the brake piston 11, is a smaller piston 13, fitting the interior of a

page_text: "
cylindrical shell 14, which fits in a chamber 15, formed in the casing or projection 7
on the cylinder head 8. As shewn in Fig. 2, the cylindrical shell 14 is open at its
inner end toward the brake cylinder and is closed at its outer end by a head 24
which forms a partition between the piston 13 and the head of chamber 15. The
head 24 is connected to, or has formed on it, a valve 16, which controls à port 17,
between the passage 10 and the chamber 15. The head 24 is in reality a piston
with a trunk 14 formed on it, which may be omitted, or a diaphragin may be
substituted for it. The stem 18 of the valve extends into a chamber 25 covered by
à cap 26 and is surrounded by a spring 19, the outer end of which bears against a
nut or shoulder on the end of the stem, the tension of said spring acting to resist
the opening,movement of the valve.. Grooves 20, are formed in the cylindrical
wall of the chamber 15 and extend from the brake cylinder space 21, into which
they open, nearly to the outer end of the chamber 15, with which they communicate,
in the normal position of the apparatus, through the small opening 22.
In the normal condition of the apparatus, that is when the brakes are released,
the parts are in the positions shown in Fig. 2, and the brake cylinder piston 11, the
piston 13, and the cylindrical shell 14, are then exposed to atmospheric pressure
only. The brake cylinder is in communication with the atmosphere through the
opening 24 branch pipe 5, and the exhaust port of the triple valve; the outer end
of the chamber 15 is in communication with the brake cylinder through the port 22
and groove 20; and the space on the outer side of the piston 13 is in communication
with the brake cylinder through the small passage 23 formed in the piston. The
passage or chamber 10 is exposed to the pressure in the train pipe with which it is
connected by the branch pipe 9.
An ordinary service application of the brake is made, as usual, by means of a
moderate and gradual reduction of train pipe pressure, caused by releasing air from
the train pipe through the proper openings in the engineers valve. The air from
the auxiliary reservoir passes through the triple valve, branch pipe 5, and
opening 24 to the brake cylinder, and moves the brake piston 11 to the left, and
with it the small piston 13. At the same time, a portion of the air that has been
admitted to the brake cylinder passes through the grouve 20, and passage 22 to the
outer end of the chamber 15, and through the passage 23 to the outer side of the
piston 13. The port 23, through the piston 13, is limited in size, but as
the movement of the pistons in making a service application of the brakes is not
very rapid, the port 23 is of sufficient capacity to permit a practical equalization
of the pressures on its opposite sides, or, at least, to prevent the production of more
than a slight degree of vacuum between the piston 13 and the head or piston 24
of the cylindrical shell 14; and as the brake cylinder is in communication with
the outer end of the chamber 15 by means of one of the grooves 20 and the
passage 22 a practical equilibrium of pressures is maintained on the opposite sides.
of the piston 13 and of the head or piston 24 of the cylindrical shell 14 during the
movement of the piston 13.
When it is desired to make an emergency application of the brakes a sufficiently
great and rapid reduction of train pipe pressure made either through the engineers
valve or by the parting or rupture of the train pipe, causes the triple valve to open
a passage for air from the auxiliary reservoir to the brake cylinder of such capacity
that the pistons 11 and 13 are moved more rapidly than in making service
applications of the brakes, and a partial vacuum is thereby formed between the
piston 13 and the head 24 of the cylindrical shell 14; the passage 23 being too
small to permit a sufficient flow of air to prevent the formation of this vacuum
when the piston 13 is moved rapidly away from head 24. The head or piston 24
of the shell 14 is then exposed on its inner side to a very low pressure and on the
outer side to the pressure in the brake cylinder which communicates, through one
of the grooves 20, and the passage 22 with the outer end of chamber 15. This
difference of pressures together with the train pipe pressure acting on valve 16
forces the cylindrical shell 1+ to the left unseats the valve 16 and permits air from
the train pipe to flow into the chamber 15 and through the grooves 20, the outer

page_text: ends of which have been uncovered by the shell 14, into the brake cylinder,
increasing the force with which the brakes are applied and causing a great and
rapid reduction of train pipe pressure which quickens the action of the brakes .on
the next succeeding car, and so on throughout the train. As the stroke of the
pistons is considerably greater than the depth of the cylindrical shell 14 or the
chamber 15, the piston 13 before it reaches the end of its stroke, is drawn entirely
out of the shell 14, and the air in the brake cylinder then rushes into the shell 14
effecting an, equalization of pressures on the two sides of the head 24 and the
spring 19. then closes the valve 16. As in the Letters Patent before referred to,
my present improvement operates to locally exhaust air from the train pipe to cause
a great and rapid reduction of train pipe pressure, and this effect is not dependent
on the subsequent disposition of the air as it may be permitted to escape to the
atmosphere, to, a separate chamber, or to the brake cylinder. There is, 'however,
a great advantage obtained by exhausting the train pipe air into the brake cylinder
because the final pressure obtained in the brake cylinder, after the auxiliary
reservoir and brake cylinder pressures have equalized is much greater than it would
be if the air from the auxiliary reservoir flowed into an empty brake cylinder.
Not only is the final pressure in the brake eylinder greater but the accretion of
pressure therein is more rapid and the brake pistons are consequently moved
outward with greater speed and force.
In Figs. 4 and 5 I have shewn a modification of my improvement in which the
operation is substantially the same as before described, but which differs slightly in
specific construction from that illustrated in Fig. 2. The grooves 20 are, in this
case omitted, and the brake cylinder space 21, communicates with the outer end of
the cylinder 15 through the passage 22 only. The branch pipe 9 from the train
pipe opens into the passage 10 which is closed by the valve 16, said valve being,
in this case, formed on the head or piston 24 of the shell 14. The valve 16 is not
provided with a stem, as in Fig. 2, but there are two stems 18, surrounded by
springs 19 which abut at one end against a head or nut on the outer ends of the
stems and at the other end against the casing. These stems are screwed into the
head 24 of the shell 14 and are acted on by the springs to resist the movement of
the shell 14 to the left and the unseating of the valve. The springs 19 and the
outer ends of the stems 18 are enclosed in the chambers 25 the ends of which are
closed by screw caps 26.
The passage 23 through the piston 13 may be omitted and a groove in the inner
surface of the shell 14 may be employed or the piston 13 may be sufficiently loose
in fit to permit the necessary flow of air around it. Further, the piston 13 may,
if preferred, be fitted to move in the cylinder 15 instead of in the shell 14 and a
piston or diaphragm to the right of piston 13 may take the place of the shell 14
and its head 24 in which case a passage around the piston 13 may be formed in the
casing 7, and the passage 23 be omitted.
In Figs. 6 and 7 I have shown two modifications in which the valve 16 is so
arranged that the train pipe pressure tends to hold it to its seat. Instead of
opening toward, the chamber 15 it opens in the opposite direction against the
spring 19 and the train pipe pressure. In order to accomplish this, instead of
connecting the valve directly to the head 24 of the shell 14, I employ a lever
which is connected at one end to the head 24 of the shell 14 and at its other end
bears on the winged stem 17 of the valve 16, the fulcrum 16' being between the
ends of the lever so that the valve 16 and the head 24 move in opposite directions.
In Fig. 6 the valve 16 opens directly into the cylinder 15 the opposite end of the
lever being connected by the bifurcated stud 16° to this head 24 to one side of its
centre. In Fig. 7 the valve 16 opens into a passage at one side of the cylinder 15
and between this passage and the cylinder 15 is fitted a slotted cylindrical bearing
through which the lever passes and which oscillates with the lever. The end of
the lever in this instance is connected to the centre of the head 24.
Fig. 8 shews a modification in which the shell or diaphragm 14 is dispensed with,
and the piston 13, instead of being connected to the brake piston is connected by

page_text: a stem 18 to the valve 16 that is kept closed on its seat by the spring 19; the
other parts having the same functions as in the preceding arrangements are marked
with same reference numbers and need not be further described.
When fluid pressure is admitted gradually and at moderate pressure from the
auxiliary reservoir to the brake cylinder through pipe 5 and passage 24" for
applying the brakes in the ordinary manner, such fluid pressure while acting on the
piston 11 will at the same time flow through the hole 23 into the space behind the
piston 13 thereby more or less equalizing the pressure on each side thereof any
excess of pressure on the inner side being more than counterbalanced by the
pressure of the spring 19 and that of the fluid pressure from pipe 9 exercised on
the valve 16 and consequently when the brakes are applied in the ordinary manner,
the piston 13 will remain in the position shewn and the valve 16 will remain closed.
But when a sudden and considerable admission of fluid pressure to the brake
cylinder is effected from the auxiliary reservoir for applying the brakes rapidly
then such sudden fluid pressure acting on the piston 13, will not pass with sufficient
rapidity through the small hole 23 to establish an equilibrium of pressure, in
consequence of which the piston 13 will be forced backwards, thereby forcing the
valve 16 open against the fluid pressure and spring pressure acting on its outer side.
Fluid pressure will thus be admitted directly from the train pipe to the brake
cylinder through pipe 9, chambers 10, 15 and passage 20, causing the brakes to be
applied more rapidly while at the same time the train pipe becomes more rapidly
exhausted of fluid pressure, which in its turn causes a more rapid and energetic
bringing into action of the brake apparatus of the next following carriages as before
explained.
The increased fluid pressure brought by the above means to act on the inner side
of the piston 13 will keep it in the described position for maintaining the valve 16
open until the fluid pressure will have passed, by degrees, through the hole. 13
sufficiently to establish an equilibrium of pressure on both sides thereof again,
whereupon the valve will be closed by its spring 19.
The brakes are taken off in the usual manner by putting the pipe 5 in
communication with the atmosphere through the exhaust port of the triple valve.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to he performed, I declare that what I
claim is :-
1. The combination with the train pipe and brake cylinder of an automatic fluid
pressure brake system, of a discharge valve, controlling a discharge opening of the
train pipe and so arranged in connection with a piston or diaphragm influenced by
the piston of the brake cylinder that when the brake piston is moved rapidly by a
sudden and considerable admission of fluid pressure in applying the brakes it causes
the said discharge valve to be opened so as to allow of a rapid discharge of fluid
pressure from the train pipe either into the brake cylinder or into a separate
chamber or into the atmosphere substantially as described.
2. In automatic fluid pressure brake apparatus, such as is referred to in the
preceding claim arranging within the extension of the brake cylinder a piston or
diaphragm connected to the valve that closes the discharge opening of the train
pipe, and a piston that is connected to the brake piston, these parts being so
arranged in combination with air passages that on effecting a sudden and
considerable admission of fluid pressure into the brake cylinder the brake piston
will actuate the piston or diaphragm of the discharge valve so as to open the same
substantially as described.
3. In automatic fluid pressure brake apparatus the combination with the brake
eylinder of an extension 7 in which is firstly a piston 13 connected to the brake
piston, and secondly a piston or moveable diaphragm 24 connected to a valve 16,
closing a passage communicating with the train pipe, the said pistons being made
to operate in conjunction with air passages 22, 23 in such manner that on sudden
and considerable fluid pressure being admitted to the brake cylinder, the piston or

page_text: diaphragm 24 is moved so as to effect the opening of the discharge valve,
substantially as described with reference to Figs. 2 to 7 of the drawings.
4. In automatic fluid pressure brake apparatus the combination with the brake
cylinder of an extension 7 in which is a piston 13 connected to a valve 16 closing
a passage communicating with the train pipe, the said piston being so arranged
with an air passage 23, that on sudden and considerable fluid pressure being
admitted to the brake cylinder, the piston 13 is moved so as to effect the opening
of the discharge valve 16 substantially as described with reference to Fig. 8 of the
drawings.
11.1002
ABEL & IMRAY,
Agents for the Applicant.