IMPROVEMENTS IN PNEUMATIC BRAKE APPARATUS FOR RAILWAY TRAINS
Year: 1882

page_text: LETTERS PATENT to Charles Denton Abel of No. 28, Southampton
Buildings, Chancery Lane in the County of Middlesex for an Invention
of "IMPROVEMENTS IN PNEUMATIC BRAKE APPARATUS FOR RAILWAY TRAINS"
A communication from abroad by George Westinghouse junior of Pittsburg,
Pennsylvania United States of America, but at present of Nice in the
Kingdom of Italy
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 13th January 1882.
'
CHARLES DENTON ABEL of No. 28 Southampton Buildings, Chancery Lane in
the County of Middlesex "IMPROVEMENTS IN PNEUMATIC BRAKE APPARATUS
FOR RAILWAY TRAINS." [A communication from abroad by George Westinghouse
junior of Pittsburg, Pennsylvania United States of America, but at present of
Nice, in the Kingdom of Italy]
This Invention relates to the pneumatic apparatus employed for working the
brakes on railway trains. In apparatus of the kind to which this Invention
relates each brake carriage is provided with a cylinder the piston of which is con-
nected to the brake rods or levers; In some cases this cylinder is at one end
extended so as to present a considerable space as an air reservoir, its other end
communicating with a pipe which is connected throughout the train from a
reservoir of compressed air on the locomotive or tender. Between this pipe and
each brake cylinder is interposed a valve arrangement so disposed that when the
train pipe is charged with compressed air the brake piston moves so as to take off*
the brakes, but when the pressure in the train pipe is relieved either purposely by
opening a cock or valve so as to let air escape from it, or accidentally by the
rupture or separation of the pipe, the brake piston is caused to move so as to put
on the brakes. Apparatus acting in this way have been described in the
Specifications of Patents formerly granted to George Westinghouse junior and
to me for Inventions communicated by him, and have been and still are in
.."מ

page_text: extensive use. The present Invention relates more particularly to the construction
and arrangement of the brake cylinder and its air reservoir and the valve apparatus
which is interposed between the cylinder and the train pipe, the object being to
secure simplicity of manufacture, facility of repair, and rapidity of action, with
considerable economy in the expenditure of compressed air required for the
operation of the brakes. The brake cylinder is made with its reservoir end
extended in the form of a dome through the centre of which passes the piston rod.
On the rod is a boss of larger diameter which has at its end a cup leather working
as a plunger in a cylindrical hole bored in a boss of the domed cover of the
cylinder, this cup leather packing serving instead of a stuffing box. The brake
piston also has a cup leather packing and a central stem extending from the
piston is faced with a leather or other packing washer which, when the piston is
at the extreme of its outstroke, bears against the central boss of the domed cover,
and prevents leakage of air around the piston rod. The cover at the other end of
the cylinder is made near its side with a projecting hollow boss which constitutes
the valve box, covered by a screw cap and having two lateral apertures, one about
its middle communicating with the train pipe, and one at its inner end opening to
the outer air. It has also at its inner end two other apertures one opening directly
into the brake cylinder and the other to a passage formed at the side of the
cylinder and having two lateral openings into the cylinder one presenting itself on
each side of the brake piston when it is at the extreme of its outstroke. The
cavity of the valve box is bored cylindrical and fitted with a piston which can
slide as a sleeve upon the stem of an escape valve which is pressed by a spring to
close the opening to the outer air. This valve stem has on it a collar against
which the piston sleeve when it moves outwards bears so as to open the escape
valve, and a groove is cut along part of the stem to give passage for air through
the piston sleeve when it is at the extreme of its instroke. In the aperture to the
side passage of the brake cylinder there is also a valve closed by a spring and
opened as the valve box piston approaches the end of its instroke. The apparatus
works in the following manner. The brake pipe being supplied with compressed
air, the pressure forces the valve box piston inwards so that it opens the valve
covering the side passage of the brake cylinder and exposes the groove in the
stem of the escape valve which valve is closed.. A portion of the compressed air
finding its way along the groove enters the brake cylinder on both sides of the brake
piston, charging the reservoir end as well as the other end of the cylinder with
compressed air. The brake piston having an equal degree of pressure on both
its sides but being smaller in area on its reservoir side by the area of the piston
rod boss, is moved outwards to the extreme of its outstroke taking off the brakes,
this movement being assisted if required by the weights or springs which release
the brakes. Now, on the pressure of the air in the train being reduced either
purposely or accidentally, the valve box piston is pressed outwards its sleeve
covering the groove in the stem of the escape valve and opening the escape
valve itself, and at the same time allowing the valve of the lateral passage
of the brake cylinder to close. Some of the air can now escape from the brake
cylinder on the one side of its piston, while the air is retained in the reservoir
on the other side of the piston, and the superior pressure of this air forces the
brake piston inwards putting on the brakes. On again raising the. pressure
in the train pipe the pressure on both sides of the piston becomes equalised
the lateral passage to the cylinder allowing air to pass from one side of
the piston to the other; the brakes are thus taken off. The valve box
described instead of being made in one piece with the head may be made
separate if desired, and in a slightly modified form which will now be
described may be applied in cases where the brake cylinder is of the ordinary form
and a separate vessel is used as an auxiliary reservoir. This modified form of
valve will then take the place of the valve arrangement usually known as "the
triple valve" employed to govern the air communications between the train pipe
and the auxiliary reservoir and between the auxiliary reservoir and the brake

page_text: cylinder also between the brake cylinder and the outer air. According to the
present Invention the triple valve is modified as follows. The body of the
valve box is bored cylindrical and fitted with a piston which can slide as a
sleeve on a rod pressed upwards by a spring butting against a collar on
the rod. Below the piston the valve box has a dome like cavity to collect
dirt or moisture, and there is a lateral communication from the train pipe to this
cavity. Above the piston there is a lateral communication to the auxiliary
reservoir, and directly above the centre of the piston is a communication to the
brake cylinder which communication is closed by the end of the rod on which
the piston slides, this end being formed as a valve. From the passage to the
brake cylinder above this valve there is a lateral passage to the outer air this
passage being closed by an escape valve pressed down by a spring and having a
small stem projecting through a hole in the cover of the valve box towards the
piston, so that when the piston is at the upper extremity of its stroke it by pushing
up this stem opens 'the escape valve. A small groove is cut in the cylindrical
lining of the valve box, which groove gives passage for air past the piston when it
is at the upper extreme of its stroke. The action of the valves is as follows.
When the train pipe is charged with compressed air, the piston is forced upwards,
the rod on which it slides closes the passage from the valve box to the brake
cylinder, but the escape valve is opened so that air can escape from the brake
cylinder, the brakes being thus taken off. At the same time air can pass the
piston by the groove and charge the auxiliary reservoir with compressed air.
For putting on the brakes the pressure in the train pipe is reduced either purposely
or it may be accidentally by the rupture of the pipe or separation of the train, and
thereupon the superior pressure of the air in the auxiliary reservoir acting on the
valve piston forces it down. The escape valve closes, and the piston bearing
against the collar of the rod on which it slides opens the central valve by which air
from the auxiliary reservoir passes to the brake cylinder and acting on the brake
piston moves it so as to put on the brakes. On again raising the pressure in the
train pipe, the valve piston rises, the supply valve to the brake cylinder closes, and
the escape valve from the brake cylinder is opened relieving the pressure on the
brake piston which moves back taking off the brakes. The collar on the rod on
which the valve piston slides is coned to form a valve fitting a seating on the boss
of the valve piston so that when the piston is pressed down, there is no escape of
air from above it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Denton Abel in the Great Seal Patent Office on the 6th July
1882.
CHARLES DENTON ABEL of No. 28 Southampton Buildings Chancery Lane in
the County of Middlesex "IMPROVEMENTS IN PNEUMATIC BRAKE APPARATUS
FOR RAILWAY TRAINS" A communication from abroad by George Westinghouse
junior of Pittsburg Pennsylvania United States of America, but at present of
Nice, in the Kingdom of Italy
This Invention relates to the pneumatic apparatus employed for working the
brakes on railway trains. In apparatus of the kind to which this Invention relates
each brake carriage is provided with a cylinder the piston of which is connected to
the brake rods or levers. In some cases this cylinder is at one end extended so as
to present a considerable space as an air reservoir, its other end communicating
with a pipe which is connected throughout the train from a reservoir of compressed
air on the locomotive or tender. Between this pipe and each brake cylinder is
interposed a valve arrangement so disposed that when the train pipe is charged
with compressed air the brake piston moves so as to take off the brakes, but when
the pressure in the train pipe is relieved either purposely by opening a cock or
valve so as to let air escape from it, or accidentally by the rupture or separation of
the pipe, the brake piston is caused to move so as to put on the brakes. Apparatus
acting in this way have been described in the Specifications of Patents formerly
granted to me and have been and still are in extensive use. The present Invention
relates more particularly to the construction and arrangement of the brake
cylinder and its air reservoir and the valve apparatus which is interposed between
the cylinder and the train pipe the object being to secure simplicity of manufacture,
facility of repair, and rapidity of action with considerable economy in the
expenditure of compressed air required for the operation of the brakes.
My improved construction of this apparatus will be readily understood on
reference to Figure 1 of the accompanying Drawings which shews a longitudinal
section of the same. The brake cylinder A is made with its reservoir end A'
extended in the form of a dome through the centre of which passes the rod B of
the piston C, which is made with a tubular extension D working as a plunger in
the tubular part A³ of the cover A¹.
A cup leather E forms an air tight packing to the plunger and serves instead of
an ordinary stuffing box.
A flange D¹ is faced with leather or other suitable material which when the
piston is at the end of its outstroke bears against the end of A² as shewn and thus
affords an additional security against leakage of air past the piston rod.
The cover A³ of the cylinder is formed with a projecting hollow boss or chamber F
which constitutes a valve box and which is closed by a screw cap G. It is pro-
vided with two lateral apertures, one at H communicating with the train pipe and
one at I communicating with the outer air. It has also an aperture K communi-
cating with the end of the cylinder and another L communicating with a passage M
that is formed at the side of the cylinder and is provided with two lateral openings
N N¹ one on each side of the piston C when this is at the extreme outstroke. The
valve box F has a piston O fitted to slide upon the stem P¹ of an escape valve P
that is pressed upon its seat by a spring Q so as to close the opening I to the outer
air. The stem P¹ has a collar P2 against which the piston O presses on its outward
motion thereby moving the valve P away from its seat and a groove P³ is formed

page_text: in the stem so as to allow for the passage of air from the one side of the piston to
the other when at its extreme instroke as shewn. The aperture L is fitted with a
valve R acted upon by a spring R¹ so as to close the opening and its stem is
extended somewhat into the valve box so that as the piston O approaches the end
of its instroke it presses against this stem and thus forces open the valve.
The apparatus operates in the following manner: The train pipe being charged
with compressed air the pressure forces the piston O inwards so that it opens the
valve R and also uncovers the groove P³ so that air entering through H can flow
along the groove P³ and enter the cylinder A on both sides of the piston through
the passages K and M thus charging both ends of the cylinder with compressed
air. The valve P being closed there is no escape of air through the opening I.
The piston C though it has an equal degree of pressure on both sides has its
area reduced on the one side by the sleeve D and consequently the excess of
pressure on the other side causes this piston and its rod to be moved outwards
thereby taking off the brakes which movement may if required be assisted by
weights or springs acting on the brakes. If now the air pressure in the train pipe
and consequently that in the outer end of the valve box F be reduced either
purposely or accidentally, the piston O will be moved outwards by the excess of
pressure in A thereby closing the groove Ps and opening the escape valve P and
also allowing the valve R to close the opening L.
As the air behind the piston O can now escape through the passage K and
opening I, the piston C is moved inwards by the superior pressure in front of it
(which is prevented from escaping as soon as the piston C covers and passes the
hole N¹) and the brakes are put on.
On again charging the train pipe, the piston O is moved inwards opening the
passage P³ and valve L, and the air pressure becoming thus again equalized on
each side of the piston C (which is facilitated by the communication by the
openings N and N¹) the piston again advances to the extreme position shown
thereby taking off the brakes.
The valve box F instead of being made in one piece with the cover A³ may be
made separate if desired; and in a slightly modified form which I will now
describe with reference to Figure 2, it may be applied in cases where the brake
cylinder is of the ordinary construction and a separate auxiliary reservoir is used,
in which form it will take the place of the valve arrangement described in my
former Patents as "the triple valve" employed to govern the air communications
between the train pipe and the auxiliary reservoir and between the latter and the
brake cylinder as also between the brake cylinder and the outer air.
Figure 2 is a vertical section of the modified valve apparatus; F is as before the
valve box and O is the piston, one end of the same fitted to slide on the stem P¹ of
the valve P which governs the passage K leading to the brake cylinder. A
branch I' from this passage leads to a small chamber containing the valve R that
closes the opening I leading to the outer air; the valve R is pressed down on its
seat by a spring R¹ and it has a small stem or needle R2 projecting into the piston
chamber so that as the piston O approaches the end of its upstroke it presses
against this stem and forces open the valve. H is the branch leading to the train
pipe and communicating with the cavity F¹ of the casing below the piston by a
passage H. L is the branch leading to the auxiliary reservoir, P³ is the spring
pressing against the collar P2 on the stem P¹ so as to force the valve P up against
its seat. The collar P is coned as shewn and the sleeve of the piston O is recessed
in a corresponding manner so that the collar acts as a valve when the piston is
pressed down upon it thus preventing any leakage of air past the stem P¹. A
small groove S formed in the lining of the casing allows passage of air when the
piston is in the raised position shown.
The action of the apparatus is as follows. When the train pipe is charged with
compressed air the pressure in the space F' forces the piston O upwards allowing
the valve P to close and opening the valve R so as to allow air from the brake
cylinder to escape through the opening I and thus keep the brakes off. At the
.
I

page_text: same time also air passes by the groove S and charges the auxiliary reservoir
through the branch L.
If now the pressure in the train pipe is rapidly and con-
siderably reduced either purposely, or accidentally through the rupture of the pipe
on the separation of the train, the pressure of the air in the auxiliary reservoir
will cause the piston to move downwards until it opens the valve P thus allowing
air to pass into the brake cylinder through the openings K' and passage K and
apply the brakes. At the same time the valve R being released from the upward.
pressure of the piston closes and prevents escape of air through I. On again
admitting air to the train pipe the piston O is raised opening the valve R and.
allowing P to close whereupon the air escapes from the brake cylinder and the
brakes are taken off.
Figure 3 is a vertical section of a valve arrangement operating in the same
manner as that shewn in Figure 2 the costruction being modified in certain
details. The parts of the valve box shewn by Figure 3 corresponding with those
in the valve box shewn by Figure 2 are marked by similar letters of reference, the
modifications being as follows:-
The air which enters the cavity F¹ is made to pass through a screen F³ of
wire gauze and porous material such as loose sponge F³ to sift it free from dust
and moisture.
The stem of the valve P and its closing spring are enclosed within a tubular
part of the stem of the piston O and a pin P₁ is passed through this tubular stem
and through a slotted hole in the stem of P. The needle R² projecting down from
the valve R rests on the upper lip of the tubular stem of O the action of O in
opening the valve R being thus more central than in the arrangement shewn in
Fig. 2.
Having thus described the nature of this Invention and in what manner the
same is to be performed as communicated to me by my foreign correspondent,
I claim :-
First. In valve apparatus for pneumatic brakes a piston sliding on the stem of
an escape valve leading to the open air and so arranged in combination with the
said valve and with a second valve leading to the brake cylinder, that in the one
position of the piston the escape valve is open and the cylinder valve is allowed to
close and in another position the cylinder valve is opened and the escape valve is
allowed to close, substantially as and for the purposes herein described with
reference to Figure 1 of the Drawings.
Second. In valve apparatus for working pneumatic brakes the piston O
working in the casing F and operating in combination with the grooved valve
stem P¹, valves P and R, springs Q and R¹ and openings I K and L substantially
as and for the purposes herein described with reference to Figure 1 of the
Drawings.
Third. The combination of the chamber F piston and valves P and R with
the passage M having openings N N¹ communicating with the brake cylinder A
on both sides of the piston C when this is at its extreme outstroke, substantially
as described with reference to Figure 1 of the Drawings.
Fourth. In valve apparatus for pneumatic brakes, a piston sliding on the stem
of a valve leading to the brake cylinder and so arranged in combination with the
said valve and with an escape valve leading to the outer air that in the one
position the piston opens the one valve admitting air to the brake cylinder and
allows the escape valve to close while in another position the piston opens the
escape valve and allows the valve leading to the brake cylinder to close sub-
stantially as herein described with reference to Figures 2 and 3 of the Drawings.
Fifth. In valve apparatus for working pneumatic brakes the piston O working
in the casing F connected at H K and L with the train pipe, the brake cylinder
and the auxiliary reservoir, the said piston being arranged to operate in combi-
nation with the valves P and R and their stems and springs Q and R¹ opening I
and groove S, substantially as and for the purposes herein described with reference
to Figures 2 and 3 of the Drawings.

page_text: Sixth. In a pneumatic brake cylinder A, a domed extension A¹ acting as an
auxiliary reservoir and having a tubular boss A2 in combination with a plunger D
attached to the brake piston C and provided with a packing washer D₁ and cup
leather E substantially as and for the purposes herein described with reference to
Figure 1 of the Drawings.
In witness whereof I the said Charles Denton Abel have hereunto set my
hand and seal this Sixth day of July in the year of our Lord One thousand
eight hundred and eighty-two.
CHAS. D. ABEL. (L.S.)