Year: 1886

page_text: I, WILLIAM WALLACE HANSCOM, residing at number 612 O'Farrell Street in the
city and county of San Francisco, and State of California, one of the United
States of America, Mechanical Engineer, do hereby declare the nature of my
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My invention has for its object a more perfect control of railway trains than has
hitherto been attainable, and at the same time to simplify and reduce the quantity
of mechanism necessary to accomplish the purpose desired, making it less subject
to rapid deterioration and less liable to interruption from slight causes, therefore
allowing it to be placed in the hands of those who have not had to acquire especial
education for the purpose of operating it.
The mechanism included in the automatic brake consists in an air-compressor
for the compressing of air, a brake-cylinder under each car connected to the
ordinary brake-gear, two train-pipes for conveying the air from the air-compressor
to the brake-cylinders, an engineer's brake-valve for directing the air into either
end of the brake-cylinder, and an automatic valve, by which the air is retained in
one end of the brake-cylinder, so that in case of the train breaking in two, the
brakes will be automatically set in every car on the train.
Referring to the accompanying drawings,
Figure 1 shows the general arrangement and construction of the various parts,
one to the other.
Fig. 2 shows crossing of couplings at meeting ends of cars.
B is the brake-cylinder, secured to the underside of the car A, this cylinder
being of such length that the piston will not move further than one-half the
length of the cylinder during the greatest travel.
C is the piston, with a rod projecting through one end of the cylinder, and having
a proper packing to prevent the leakage of air, the rod being connected to the
brake-levers or brakes by any suitable means required by the different arrange-
ments of brake-rods and levers in use.

page_text: D is one of the train-pipes passing through or connected at each side of a
valve F, this valve being connected to the brake-cylinder B, by a short pipe or
passage, as shown.
Near each end of the car, the pipe D has a cock H, for the purpose of closing or
opening either end of the pipe as may be desired. To these cocks at either end of
the car are connected pieces of flexible hose L, having suitable couplings for uniting
them to corresponding pipes on any adjacent car when the train is made up. The
passage from the valve F, is connected with the cylinder B, at or near its end, so
that the pressure of air coming through this valve may be exerted on the side of
the piston opposite the piston-rod.
A cock Y may be attached to the cylinder B, to let out the pressure of air when
desirable. E is a train-pipe connected with the brake-cylinder by a pipe G, which
opens into the cylinder at the opposite end from the pipe connecting with the
valve F.
This pipe has also cocks I, and flexible hose connections K, and for a similar
purpose to those shown on the pipe D. These pipes are shown so arranged that in
coupling the similar pipes on two connected or coupled cars, the flexible pipes or
hose will cross the center line of the car.
If desired, the pipes may be so carried that the coupling of the pipes or hose
will be at diagonally opposite corners of each car, or at whatever point may be
most convenient.
N is the air-pump. M is the steam cylinder for operating the air-pump, taking
its supply of steam from the usual source, the two cylinders being, preferably,
placed in line, so that their pistons are united by a common piston-rod.
I prefer to place the air-compressing cylinder above the steam cylinder, in order
to prevent the condensed water which may escape from the stuffing-box of the
steam cylinder from entering the air-cylinder, which would be likely to occur, and
make considerable trouble, if the cylinders were reversed.
R is a pipe leading from the air-pump into the valve-chamber which contains the
valve P.
This valve is cylindrical and is nicely fitted to the chamber in which it oscillates
or partially rotates about its axis.
It has ports 1, and 2, through which air is admitted from the pump N to the
train-pipes D, and E, either or both at the same time, and it serves also to exhaust
the air from either of the pipes D, or E, into the exhaust-port O.
The dotted lines show the successive positions of the valve-ports when the valve
is oscillated, first, to close the port through which air may be admitted into the
pipe D, and at the same time have the port 1 slightly open, so that air may
continue to flow into the pipe E, second, when the valve is still farther oscillated,
the valve-port opens communication between the pipe D and the exhaust-pipe O,
by which air is allowed to escape. The valve F, which is connected with the
cylinder B, at or near the end, as before explained, consists of a chamber having
three openings a, b, and c, the train-pipe D connects with the two openings a, b,
forming with them a coupling or T, and serving with the opening c to connect the
pipe with the brake-cylinder B.
Within this chamber is a seat, having a valve d fitted to close against it out-
wardly. The valve-seat is, preferably, of metal, and has an elastic face e, where
it rests upon the seat.
This valve is attached to the cap f of the chamber by springs g, which act to
keep it close upon its seat.
This valve, when it opens, will open toward the cylinder, and against the
pressure of the springs before mentioned. It has an opening made through it,
forming a seat for the valve i, which opens in the opposite direction from the
valve d.
This valve has a stem or spindle j, and is kept closed upon its seat by
a spring k, which is made of such stiffness that the valve i will only open when a
definite pressure has been applied under it.

page_text: The spring may be put under the valve, as shown, or on top, so as to be adjusted
to any tension required.
The directions of the currents of air are shown by the arrows. A pressure-gauge
may be placed on each of the pipes D, and E, near the valve P, so that the
difference in pressure in the two pipes may be noted in operating the brakes.
The operation of the mechanism will be as follows:-
The ends of the pipes D, and E, which are beyond the brake-cylinders, being
closed, the air-pump is started, and the air is compressed into the brake-cylinders
and the pipes D, and E, equally through the ports 1, and 2, and in the valve P,
the exhaust being open.
After a sufficient pressure is generated to operate the brakes, the valve P is
turned so that the opening through the port 2, in the pipe D, is partially closed,
and if necessary so much so that a slight opening may be made between the
pipe D, and the port O, thus creating a greater pressure in the pipe E, than there
is in the pipe D.
This difference of pressure acting on the two sides of the piston C in the brake-
cylinder B, will be just sufficient to keep the piston drawn backward so as to keep
the brakes off the wheels.
By observing the two gauges on the pipes D, and E, the engineer can always,
by means of the valve P, regulate the difference in pressure to a nicety.
To apply the brakes, the valve P is reversed in movement so that the excess of
pressure will be in the pipe D, when the piston C will be forced forward by the
excess of pressure on one side, and the brakes will be applied with a force
corresponding to the difference of pressure on the two sides of the piston.
It is intended that the springs usually applied for taking off the brakes shall
be a little stronger than is necessary to take them off when the pressure is equal
on both sides of the piston, and then when the train is running and air-pressure
is equal in both pipes D, and E, the valve P will be held in mid-position, and the
communication between the pipes will be free through the valve P, and its ports 1,
and 2. The valve d is to be so lightly loaded that a slight difference of pressure
on the two sides will open it and allow air to pass freely through, but the valve i
is loaded so that the pressure required to open it will be something more than is
required to operate or apply the brakes, so that whatever pressure may exist in
the pipe D, will also be found in the end of the brake-cylinder to which the valve
is connected, and any decrease of pressure in the pipes D, and E, will not reduce
the pressure on that side of the piston.
On the other side of the piston, the cylinder being in free communication with
the pipe E, any diminution of pressure in that pipe will instantly reduce the
pressure in the cylinder at this end, and the air being confined in the opposite end
of the cylinder will exert its pressure in expanding, and force the piston forward
to apply the brakes.
The change of pressure may be effected by the engineer moving the valve P in
either direction. Should any accident occur by which either or both of the pipes D,
and E, be broken, the brakes will be instantly applied by the confined air under
pressure in the acting end of the brake-cylinder B. To take off the brakes, the
valve P will be moved so that the greater pressure will exist in pipe E, and the
piston will be forced back.
It will be seen that while the brakes will be applied automatically, should any
accident occur so as to cause a leakage in either of the pipes D, or E, the engineer
in applying the brakes can exert any degree of force requisite, and can continue to
force air through the pipe D, and the valve F, into the brake-cylinder, should any
loss of pressure by leakage or otherwise occur, without having to release the brakes
for the purpose of re-charging any reservoir.
This is very important in going down very long grades when the brakes have to
be constantly applied, as any taking off brakes may allow the train to increase its
speed to a dangerous extent.

page_text: 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--
1. Mechanism for operating air-brakes, comprising a pump for compressing the
air, a valve for distributing the air to the brake-cylinders, the valve being con-
structed so that the current of air may flow direct from the pump without the
intervention of a reservoir or other obstruction into either or both ends of the
brake-cylinder at the same time, two train-pipes connected to this valve and to
the opposite ends of the brake-cylinder, both of these pipes permitting an unob-
structed flow of air into the cylinder, and an unobstructed flow from the cylinder
through one of the pipes, the other pipe having a retaining pressure-valve
preventing the outward flow of air from the other end of the cylinder below a
fixed or regulated pressure, substantially as described.
2. The operating valve P, having the admission-opening R, the divided channel
or passage T, the two ports for the pipes D, and E, the exhaust-opening O, and the
ports 1, and 2, so constructed that when the valve P, is in or near its mid-position
there will be a direct communication from the admission-opening R, through the
ports 1, and 2, of the valve into the openings or ports for the pipes D, and E,
substantially as shown, and for the purpose described.
3. In air-brake mechanism, an air-pump, brake-valve, two lines of pipe, and
brake-cylinder with its piston, in combination with a valve which will allow free
admission of air to one end of the brake-cylinder and will permit the outflow when
the pressure in the cylinder is above a fixed amount, substantially as shown and
described.
4. The retaining pressure-valve having the chamber F, with the openings a and b,
for attaching pipes, the metal valve C, having an elastic face, and held to its
position on the seat by springs, this valve having openings through it which are
closed by a valve i, which opens in an opposite direction from valve d, the valve i
being loaded so that it will only be opened with a fixed pressure, substantially as
shown and described.