IMPROVEMENTS IN AIR BRAKES FOR RAILWAY VEHICLES
Year: 1886

page_text: Date of Application, 26th Oct., 1886
Specification Accepted, 7th Jan., 1887.
I, SYLVANUS REED KNEELAND, of Boston, in the County of Suffolk, State of
Massachusetts, U.S.A., Machinist, do hereby declare the nature of my invention for
"IMPROVEMENTS IN AIR BRAKES FOR RAILWAY VEHICLES," and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
My invention relates to that class of Air Brakes which are known as "automatic";
and it consists in a novel construction and arrangement of the parts as hereinafter
more fully set forth and described, by which a more effective apparatus and system of
the class above premised is produced than is now ordinarily employed and by means
of which the brakes are prevented from "creeping." This latter is occasioned by the
pressure in the main air supply pipe leading from the pump becoming less than the
pressure in the auxiliary or storing reservoir, due to various existing causes and
circumstances.
Furthermore my device is so arranged that unless the brakes are to be intentionally
set or operated no movement of said service containing my improvements will occur,
and any air passing from the auxiliary to the brake-cylinder will be diverted and
escape to the atmosphere; hence while the position of the various parts so remain, it
is impossible to set the brakes as the brake cylinder is rendered inoperative by the
escape of the compressed air, the actuating agent.
The nature and operation of the improvement from the description following will be
readily understood by all conversant with such matters.
Figure 1 is a plan view showing the relative arrangement of the valves; Figure 2
a vertical section taken in line ca in Figure 1. Figure 3 is a vertical section on
line y y in Fig. 1; and Figure 4 is an enlarged section of the main valve. Figure 5
is a general plan of an air-brake system embodying my invention, while Figure 6
is a vertical section of a triple valve, so called, which is shown for convenience of
reference in the description of the invention. Figure 7 is a sectional plan on line 33
in Figure 4.
In the drawings A represents what I term the main valve; B a valve chamber
within which operates the auxiliary valve ; while C is a check valve.
The main valve is located between the main air supply pipe D and the triple valve
S, and as shown, is connected to said pipe D by the induction branch pipe T and with
the triple valve by the eduction pipe E. Communication from the triple valve to the
auxiliary cylinder or storage reservoir A' is had through the pipe R.

page_text: The brake-cylinder is represented at Aand the latter united and connected with
the other operating parts of the system by the pipe H, which enters the triple valve.
Within said pipe is inserted a check valve C, so disposed as to prevent air returning
to the triple valve from the brake-cylinder A2, but will permit free passage of air to
the latter from the auxiliary cylinder A¹ to actively operate the brakes.
The valve chamber B is interposed between the pipe H and main valve A, being
properly coupled therewith by the T shown at J and other suitable connections, it
being understood that all of the parts mentioned are so united as to communicate with
each other.
The case of the main-valve is made in two sections bl, which are screwed together
as shown at m, while a flexible annular diaphragm fis secured between them.
An annular valve-seat r is centrally mounted on the diaphragm by means of the
washer i, nutt and screw k, said washer resting on the bottom or inner face of section b;
when the valve is closed as shown in Figure 4.
A hub projects from the center of the part forming the valve-seat, said hub being
centrally bored and screw-threaded to receive the screw k.
V
Disposed around the hub there is a coiled spring a, and resting against the outer
end of this spring is a metallic disk u.
A leather disk d is placed outside the metallic disk u, which rests on the valve-seat;
and outside of the leather disk there is a similar metal one w which is slightly smaller
than the disk d, the disks d w being provided with a series of holes or air-ducts
opening against the outer side of the metallic disk u.
A shoulder g is formed on the screw k, and when said screw is turned fully into the
hub v, the disks d w will be clamped between said shoulder and the metallic disk u,
which latter rests against the outer end of the spring a and is adapted to move back
and forth slightly on the body of said screw between the top of the hub vand disk d,
as the spring is compressed and expands.
A series of air-holes or ducts y are formed in the washer i, diaphragm f, and seat r,
so that when the air is forced from the main supply pipe D into the valve through the
induction pipe T, it will pass through said ducts and out under the edges h of the disk
d, said disk yielding to permit the air to pass into the chamber N of the valve, only
after movement of said valve and diaphragm, and thence through the pipe E into the
triple valve S.
The screw kis elongated to form the stem L, which is fitted to slide in the elongated
nipple O, on section of the valve A, and in a screw-plug M inserted in the outer end
of said nipple, a packing P being inserted beneath said plug to cause the stem to work
air-tight in said nipple.
The valve proper j, located in the valve chamber B, opens in the direction of the
pipe H and is fitted with a stem p, adapted to engage the stem L in the valve A.
A stop-cock Q is attached to the valve-chamber B, said stop-cock ordinarily being
left open during the working of the brake.
The check-valve Cis of ordinary construction, as shown in Figure 3, and opens in
the direction of the brake cylinder A2; while the same valve prevents return of air to
the auxiliary air-tank A¹ shown as adjoining and connected with the triple valve in
the usual manner.
"
"
It is well known that in automatic air-brakes the brakes are very liable to gradually
creep on
or become "set" accidentally by the independent action of the triple-
valve, and to obviate this objection or difficulty is the design of my present invention.
This "
creeping or setting" of the brakes so called can readily be understood by
reference to Figure 6. which shows the triple-valve S.
This triple-valve contains a piston 2. working in the chamber 3. and operates a slide
valve 4. Air enters from the pipes D T through the four-way cock 5. into receiver 6.
and thence passes to the chamber 3. forcing the piston up, and uncovering a small
feed duct in the upper part of the chamber, which permits air to flow past the piston
into the auxiliary reservoir A', while at the same time, there is an open communication
from the brake-cylinder A² to the atmosphere by means of the valve j and discharge-
cock Q.

page_text: Air will continue to flow into the auxiliary reservoir until it contains the same pres*
sure of air as the main brake pipe D, when the piston 2. is maintained in an upraised
or normal position.
To apply the brakes with their full force, it must be understood that the pressure in
the main pipe D must be equal to or greater than that in the auxiliary cylinder A¹,
with the operative parts set in the positions as shown in Figures 2. and 6. In such
figures the main valve A is thrust towards and against the auxiliary valve j.which is
open, while the piston 2 in the triple-valve S is resting in its extreme upper position.
Now when the compressed air in the main pipe D is allowed to escape, the greater
pressure in the auxiliary reservoir A¹ forces the piston 2 down below the feed duct,
thus preventing the return of air from said reservoir to the main brake pipe D. As
the piston descends it moves with it the slide-valve 4, so as to permit air to flow
directly from the auxiliary reservoir A¹ into the brake-cylinder A2, which forces the
pistons within the latter to advance and set the brakes. This result is a consequence
upon the sudden diminution of the pressure in the main pipe, whereby the valve A is
operated to close the valve j, and the latter prevents escape of any air through the
cock Q, and the brake-cylinder A2 is actively operated.
The brakes are released by again increasing the pressure of the air in the main
pipe D by aid of the pump (not shown), which pressure becoming greater than that
in the auxiliary reservoir A¹, forces the piston 2 back or upwards, recharging the
auxiliary reservoir A¹, and at the same time permits air in the brake-cylinder to
escape by closing communication between the brake-cylinder A2 and the cylinder A',
and simultaneously opening the valve j at the time of opening the valve A.
To apply the brakes gently a slight reduction is made in the pressure in the main
pipe, which moves the piston down slowly until it is stopped by the coiled spring 7.
At this point the opening 8 in the slide valve is opposite the port 9, and allows air
from the auxiliary reservoir A¹ to feed through a hole in the side of this slide valve,
and thence by the opening 8 into the brake-cylinder A2 by way of the pipe H.
When the pressure in the auxiliary cylinder A¹ has been reduced by expanding into
the brake-cylinder A2 until it is the same as the pressure in the main brake-pipe D,
the graduating spring 7 pushes the piston up until the small valve closes the opening 8.
This causes whatever pressure is in the brake-cylinder A² to be retained, thus
applying the brakes with a force proportional to the reduction of pressure in the
main brake pipe.
When the train is in motion in case the pressure in the main pipe D, for any cause,
as by leakage or otherwise, becomes less than that within the auxiliary cylinder A',
the piston 2 gradually drops, and with it the slide-valve 4, which opens communication
between the cylinder A¹ and brake-cylinder A2 by means of the pipes R, duct 9, and
pipe H to gradually set the brakes.
To obviate this difficulty, I make use of the auxiliary valvej interposed between the
main valve A and pipe H, introduce the check-valve C in the pipe H, elongate the
stem L and so connect and arrange the valve A and valve-chamber B that the valve j
may be opened by the stem of the valve A, and provide the stop-cock Q as a leakage
opening to the valve j and through it for the brake cylinder A2.
In the use of my improvement, when the pressure is put on by the pump the air
enters the main valve A, raises the diaphragm, forces the stem L forward into contact
with the stem p of the valve j and opens the latter, the diaphragm, being composed of
leather, rubber, or other analogous material, yielding to permit the stem to advance as
described.
After the stem L has advanced to its fullest extent and the valve ; is opened, the air
passing through the ducts y will raise the disk d from the seat in the valve A, pass
out under said disk at h into the chamber N, and thence through the pipe E to the
triple-valve and auxiliary air-tank A¹ in the usual manner; but the stop-cock Q, being
open, the air in the brake-cylinder A2 will rush back through the pipe H, close the
check-valve C and escape through the stop-cock, thereby speedily and effectually
relieving the brakes.
It is evident the valve j will always remain open while the pressure is greater in the

page_text: main air-pipe D. than that in the auxiliary cylinder A¹. Furthermore it is obvious
that if the triple-valve or piston 2 is accidentally operated to open the outlet from the
auxiliary air-tank A¹ to the brake-cylinder, thereby permitting air to pass to the latter
through the valve C, the brakes will not be operated thereby, as the main-valve A will
not move except upon sudden escape of the air in setting the brakes, and the valve j
remains open to permit escape of air through the stop-cock Q.
The valve j being open and the brakes off, as described, if now the air in the main
pipe is released and the pressure suddenly reduced, the piston 2 in the triple-valve S
will drop and communication is established between the triple-valve and the brake-
cylinder A², thereby permitting the air to pass from the auxiliary air-tank A¹ to the
brake-cylinder A2 and put on the brakes, the valvej being closed when the pressure is
removed from the valve A.
By closing the stop-cock Q, and removing the check-valve C, the brake may be used
as a direct air brake in the usual manner.
When the pressure is removed in the valve A, the air from the pipe E will pass
through the ducts z, and force the disk u down upon the spring a, thereby compressing
said spring and escaping between the disks ud by way of the ducts y into the pipe T,
and thence into the main pipe D.
In making up trains, and also in coupling cars into trains on the road, when the cars
are provided with the ordinary automatic air-brakes, the air pressure is sometimes
found to vary greatly in the brakes of different cars, thus rendering it difficult to
operate the brakes satisfactorily. My invention overcomes this difficulty, the auxiliary
valve j and leakage opening equalizing the pressure throughout the train.
I do not confine myself to the construction of the main valve A, precisely as shown,
as any suitable valve for performing the same functions may be employed; nor to
using the stem p in the valve j or otherwise constructing said valve, as shown, as any
suitable auxiliary-valve adapted to be opened by the main valve may be employed; nor
to the use of the stop-cock Q, as a leakage-pipe or opening may be employed in connec-
tion with the auxiliary valve which is not provided with a stop-cock; nor to the use of
the check-valve C, as this may be dispensed with if desired.
As I have before premised, in the making up of trains it frequently occurs that two
or more cars are coupled in which the auxiliary cylinders or air-reservoirs A¹ vary
greatly in pressure, and to illustrate the advantages of my invention I will assume that
a car, No. 20, carries the tank A¹ shown in Figure 5., which is under a pressure of
80 pounds, and this car is now coupled with a second car, say No. 25., provided with a
similar tank or auxiliary cylinder under a pressure of 50 pounds. It is evident that
the piston 2 in the triple-valve S on car No. 20 can not be raised or actuated to release
the brakes except by an equal or greater pressure throughout the main pipe D con-
necting the brake system on the cars; hence it must be assumed that the brakes are
set on car No. 20. Ordinarily the pressure must be brought to 80 pounds or more to
release the brakes, or else they must be released by hand.
Now in my apparatus a lower pressure will release a higher pressure, as I will
proceed to explain. The pump now started will be supposed to attain a pressure
equal to or slightly greater than the lowest pressure in any tank A¹ on the train, in
this case assume car No. 25 with 50 pounds; hence the triple valve piston is actuated
and simultaneously the diaphragm valves A on every car and with them the auxiliary
valves are moved; thus the high pressure in any auxiliary cylinder A¹ is overcome by
means of the large area of the diaphragm valves A compared with the auxiliary valves j
actuated thereby.
Thus at the moment of opening the valves ; by the impulse of the diaphragm
valves A in the act of recharging one or more auxiliary cylinders under low pressure,
the corresponding cylinders A' under high pressure are at once reduced to a pressure
equal to the lowest pressure in any one storage cylinder A'. When this reduction in
pressure is accomplished, and not until then, does the piston 2 in a triple valve con-
nected with any such cylinder A' under high pressure rise. When it is so actuated
the supply to the brake cylinder A2 is stopped and the brakes are entirely released.
Thus it is not necessary to raise the pressure throughout the train of all the low

page_text: pressure cylinders A¹ in order to release one under a high pressure, but the latter can
be reduced and the brakes released; then if desired the pressure in the cylinders A¹
throughout the train can be restored and maintained at any high pressure deemed
most efficient.
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 :-
1st. In an automatic air-brake system, the combination with a main valve, located
in and operated by the air impulses passing through the main pipe, of the auxiliary
valve independently connected, but simultaneously actuated with and by said main-
valve, whereby the pressure in the air-brake cylinder is varied at times, substantially
for the purposes herein described.
2nd. In an automatic air-brake system, the combination with the air-brake cylinder
and its operating pipe open to the atmosphere, of the valve located therein and actuated
by the diaphragm valve in the main air supply pipe, substantially as herein set forth.
3rd. In an automatic air-brake system, the combination with an air-brake cylinder
and connecting air pipe, of the auxiliary valve actuated by the main air valve of
greater superficial area, whereby a brake set at high pressure may be released by a
lesser pump pressure, substantially as herein described.
4th. In an air-brake for rail-way cars of the character described the combination of
the following instrumentalities, to wit: a main valve, an auxiliary valve, a check
valve, and a stop-cock, the main valve being provided with an induction pipe con-
necting it with the main pipe, with an eduction pipe connecting it with the triple-
valve, and with a stem adapted to open the auxiliary valve; the check-valve being
disposed between the triple-valve and brake cylinder and suitably connected there-
with; the auxiliary valve disposed between the main valve and pipe connecting the
triple-valve and brake cylinder, and adapted to be opened by the stem of the main
valve; and the stop-cock disposed between the main and auxiliary valves, substantially
as described.
5th. In an air-brake of the character described, the valves Aj C, pipes DE H and
stop-cock Q, or a leakage opening combined and arranged to operate substantially as
set forth.
6th. In an air-brake of the character described, the valve-chamber B provided with
the valvej and having a leak opening or stop-cock, in combination with the valvo
stem L and operative mechanism therefor, substantially as described.
7th. In an air-brake of the character described, the valve A, provided with the
pipes DE, valve chamber B, provided with a leakage opening or stop-cock and
pipe H, combined and arranged to operate substantially as set forth.
8th. In an air-brake of the character described, a main valve and an auxiliary valve,
the auxiliary valve being provided with a leakage opening or stop-cock and adapted
to be opened by the main valve, in combination with pipes for properly connecting said
valves with the main pipe, triple-valve, and cylinder of the brake, substantially as
described.
9th. In a valve for air-brakes the flexible diaphragm f, seat r, provided with the
ducts y, screw, nut t, stem L, spring a, disk u and disks dw, provided with the
ducts " combined and arranged to operate substantially as set forth.
10th. In a valve for air-brakes the section b, provided with an induction opening,
the section I, provided with an induction opening, flexible diaphragm f, seat r, spring a,
disk u, disks w d provided with the ducts z, screw k, nut t, stem L, ways for said
stem and means for properly packing the same combined and arranged to operate
substantially as described.
SILVANUS REED KNEELAND.