OR CONNECTED WITH RAILWAY BRAKES."
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Henry Kesterton at the Office of the
Commissioners of Patents on the 2nd December 1879.
HENRY KESTERTON, of Birmingham, in the County of Warwick.
IN OR CONNECTED WITH RAILWAY BRAKES."
"IMPROVEMENTS
This Invention, relating to improvements in or connected with railway brakes, has
reference chiefly to the apparatus used in actuating the said brakes and applies
equally to the use of pressure or vacuum for that purpose.
According to one mode of carrying out my Invention as applied to the actuating
of railway brakes by means of compressed air, I use a cast iron cylinder (termed
the reserve chamber) capable of containing sufficient compressed air to apply the
brakes several times. At each end of this reserve chamber another short cylinder
is fixed, in which work in opposite directions the pistons actuating the brake gear;
outside the reserve chamber about the middle of its length with its axis per-
pendicular to that of the other cylinders, I cast a small cylinder termed the valve
chamber, which is connected to the interior of the reserve chamber to the spaces at
the back of the pistons in the brake cylinders and to the main connecting pipe of
the train; by means of passages cast in the sides of the reserve chamber, a valve
moving vertically in the valve chamber and put in motion by a slight increase or
decrease of pressure in the main pipe controls and regulates the flow of air through
these connecting passages from the reserve chamber to the brake cylinder to apply
the brakes and from the brake cylinder to the open atmosphere to release them.
According to a modification of the preceding arrangement, I dispense with the
separate reserve chamber and join the two brake cylinders, adding to their length
sufficient to provide for the working of the brake pistons and also to contain tho
reserve of compressed air. The motion of the pistons is restricted to a small space
between, and at the back of the two pistons in the middle of the length of this
cylinder the compressed air is stored in the two larger spaces, one at each end of
the cylinder in front of the pistons; these three spaces separated from each other
by the two pistons are connected to each other and to a small valve chamber cast
on the side of the main cylinder, in which works a valve controlling and regulating
the admission or discharge of the compressed air through the different connecting
passages as in the previous modification.

page_text: The regulating valve consists of a small piston carrying two hollow stems, the
upper one of which is larger in diameter than the lower one, and is perforated by
two or more long narrow openings or ports; the lower stem is not perforated, but
its end is bevelled to make its seat air tight on a rubber pad, the piston and stems
are cast in one and have a vertical motion in the valve chamber produced by the
increase or decrease of pressure in the main connecting pipe. The two ends of the
valve chamber are closed by deep screwed caps, which keep the gun metal lining of
that part of the chamber where the piston works in place, and serve to connect the
valve chamber with the passages leading to the brake cylinders by means of a small
chamber bored in the centre of each one; the valve stems fit these small chambers
closely, but are free to move up and down in them when the pressure in the main
connecting pipe is reduced, the valve falls and the long narrow ports in-the upper
stem are uncovered more or less according to the reduction of the pressure; in this
position air passes freely from the reserve through the valve chamber and charging
passages into the brake cylinder and applies the brakes, at the same time the lower
stem moves over and closes the discharge passage; when the pressure in the main
pipe is increased the valve rises until the ports in the upper stem are closed, and a
rubber pad resting on the upper side of the piston is pressed against a projecting
edge formed round the chamber in which the upper stem works, no leakage
therefore can take place from the reserve chamber when the breaks are off the
wheels, at the same time the lower stem uncovers the discharge passage and
releases the brakes. As the pressure on the upper side of the valve piston is less
than on the lower side, owing to the difference in diameter of the two stems I
ensure the necessary prossure against the rubber pad to prevent the valve opening
until a reduction of pressure in the main pipe takes place when the reserve
chamber and main pipe are fully charged.
In applying my Invention to the actuating of railway brakes by means of
vacuum, I construct the apparatus upon the samo principle as when employing
compressed air. In this case I prefer to use cast iron cylinders containing two
pistons moving in opposite directions, instead of one piston or its equivalent as now
used;
the general arrangement of the pistons in the cylinder is the same as that
described in the pressure arrangement last herein before referred to, excepting that the
end spaces are used not to store compressed air, but instead of the separate vacuum
reservoirs generally connected to the brake cylinders, for which purpose the brake
cylinder can be made as long as is necessary beyond what is required by the motion
of the pistous. The brakes are applied by admitting atmospheric pressure between
the two pistons whilst the vacuum is retained in the spaces or reservoirs in front of
the pistons or ends of the cylinders, and the brakes are released by first closing the
communication with the atmosphere and then opening free communication to all
three spaces consequently to both sides of both pistons, thus producing perfect
equilibrium which releases the brakes promptly without delaying until the usual
working vacuum is produced by the action of the ejector on the engine; but when
the vacuum is restored again, the spaces on both sides of the pistons are equally
exhausted because the free communication exists until the brakes are again
applied.
The three spaces in the cylinder, and therefore the opposite sides of the two
pistons, are connected together and to a small valve chamber as in the pressure
arrangement by passages cast in the brake cylinder, but in order to regulate the
distribution of air through them I use in this case two small pistons instead of one,
each of which carries a valve, one for controlling the admission of the atmosphere,
the other controlling the passage communicating to all parts of the cylinder. The
valve pistons are so arranged that when air is admitted to the space between the
two brake pistons it passes to both sides of the valve pistons, consequently when a
slight vacuum is produced on one side of them through the main connecting pipe,
the oue controlling the admission of the atmosphère éloses on its seat, the other one
is lifted from its seat and allows the air between and at the back of the two.

page_text: brake pistons to pass to their front sides until equal pressure exists on both sides
which releases the brakes instantaneously, but when an increase of pressure takes
place the passage giving free communication to the different spaces is closed by its
own valve first, then the other valve being lifted from its seat admits air into the
space between the two pistons and applies the brakes.
In some cases I dispense with the regulating valve, valve chamber, and reservoir
chambers, and make the brake cylinder only sufficiently long to allow the necessary
movement of the pistons which divide the cylinder into three spaces, each of which
is in direct communication with the main connecting pipe through passages cast in
the bottom of the cylinder. The passage to the space between is much larger than
those leading to the spaces before the pistons which open into the cylinder in such a
position that the forward movement of the pistons when applying the brakes covers
them and prevents air passing into the spaces before them, and at the same time
it can pass freely into the space between the pistons and apply the brakes. The
forward movement of the pistons compresses the small amount of air left in the end
spaces until, by the time the brakes have done their work, the pressure in them
will be sufficient to move the pistons back again and release the brakes as soon as
a slight vacuum is produced in the main connecting pipe. In moving back again
the pistons will uncover the branch ports or passages to the front spaces when all
the spaces will be again in direct communication with the main pipe and will be
equally exhausted. Owing to the small movement of the pistons in actuating the
brakes in this arrangement, the volume of air it is necessary to put in motion is so
small that it will of itself ensure great promptitude and energy of action in the
application of the brakes, and although its exhaustion is a slower operation, the
compression produced at the front of the pistons will ensure equally prompt action
in releasing them. By the arrangement of the passages connecting the several
spaces to the main connecting pipe and by discarding all valves and other details,
this arrangement is equally applicable by admitting steam from the engine boiler
to the main connecting pipe, in which case the intensely rapid action produced by
steam of the pressure usually carried by locomotives flowing into a vacuum cannot
be equalled by any arrangement of auxiliary or emergency valves.
In the several modifications the pistons are made airtight in the cylinders by
means of strong diaphragms of rubber and canvass, or rubber and copper wire
gauze, or other suitable material; one edge of the diaphragmn is bolted between
suitable faces provided on the piston and moves with it, the other is bolted between
flanges cast on the brake cylinder and is rigid; a suitable recess is provided round
the interior of the cylinder to allow the diaphragm to oscillate with the movement
of the pistons, the sides of the recess are of such a shape that combined with tho
slack portion of the diaphragm it ensures that the latter is supported during the
movement of the pistons; the piston rods where passed through the cylinder ends
are packed in the same manner, the object being to prevent friction and to obviate
leakage through wearing away of the packing, and also obviate any necessity for
lubrication.
In applying brake blocks to both sides of a pair of wheels I use two levers one
on each side of the pair of wheels actuating the blocks of both wheels on that side.
In order to apply the four blocks simultaneously it is necessary to move the levers
in opposite directions, I therefore connect those levers of each pair of wheels having
a forward motion to that piston of the brake cylinder having a forward motion,
and those having a backward motion to the piston having a corresponding motion;
this arrangement reduces the distance to be travelled by the pistons when applying
the brakes and therefore increases their rapidity of action.
I connect the inain connecting pipe between each carriage by means of the
hollow castings alike in shape and size, one end of each is smaller to enter the
flexible portion of the main pipe, the other is enlarged to contain a conical valve,
and its seat having ports or passages through both equal to the area of the main
pipe. The valve has a turning motion opening and closing these ports, the object
being to prevent the escape of compressed air or the admission of the atmosphere

page_text: when it is necessary to separate a train or remove a carriage. Each of these
similar castings forms half the coupling and has fixed on its front end an elastic
pad or face resting on the conical valve, so that.when the two halves are forced
together the elastic faces form an air tight joint. Each half is provided with a
short projection so formed as to engage with a strong steel spring fixed on the
other half, the faces of these projections are made slightly angular, therefore when
the two halves are forced together and twisted round the projections engage with
their corresponding steel springs, and owing to the angular faces of the projections
the more they are twisted the tighter the two elastic faces are forced together, and
as the conical valves are connected by the elastic pads they are turned and their
passages opened at the same time; when twisted back again the valves are closed
retaining the compressed air or preventing the destruction of the vacuum and the
two halves are uncoupled, but when separated without twisting the projections
depress the steel springs and the two halves are parted, but as the valves have not
been turned round they remain open and discharge the compressed air from the
pipes or admit air; in the case of vacuum the brakes will thus be applied auto-
matically in case of the train parting or a carriage becoming detached while the
train is in motion.