IMPROVEMENTS IN VACUUM BREAKS FOR RAILWAY TRAINS
Year: 1878

page_text: LETTERS PATENT to John Imray, of Southampton Buildings, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN VACUUM BREAKS FOR
RAILWAY TRAINS." A communication from abroad by Joseph Hirsch, of
Cologne, in the German Empire.
Sealed the 25th February 1879, and dated the 10th December 1878.
PROVISIONAL SPECIFICATION left by the said John Imray at the Office
"IM-
of the Commissioners of Patents on the 10th December 1878.
JOHN IMRAY, of Southampton Buildings, in the County of Middlesex.
PROVEMENTS IN VACUUM BREAKS FOR RAILWAY TRAINS." [A communication
from abroad by Joseph Hirsch, of Cologne, in the German Empire.]
This Invention relates to the working of the brakes of a railway train by means
of atmospheric pressure acting against a partial vacuum on pistons connected to the
brake levers, the partial vacuum being produced by the exhausting action of steam
jets, and the reduction of pressure being communicated throughout the train by a
pipe coupled from carriage to carriage and connected by branch pipes to the several
break cylinders. The present improvements apply to several parts of the apparatus,
namely, the arrangement of the steam jets for rarefying, the coupling of the pipes
from carriage to carriage, and the break cylinder and its valves. Although the
several improved portions of the apparatus may with most advantage be used in
combination some of them may be employed without the others; for example, the
couplings and the arrangement of brake cylinder may be employed in cases where
the partial vacuum is produced in any known manner, and the jet apparatus may
be used for exhaustion when couplings and brake cylinders of known construction
are employed in the working of vacuum brakes. The improved exhaust apparatus
is arranged in such a manner that the amount of rarefaction produced by it can be
readily varied as well as the rapidity with which the exhaustion is effected so as to
suit different conditions in the working of the breaks by affording means of quickly
producing a considerable amount of rarefaction when it is desired to apply the

page_text: brakes speedily and strongly, or of simply maintaining the rarefied condition of the
apparatus so as to provide against leakage. For this purpose steam from the engine.
boiler is admitted into the lower part of a casing, from which there are several
passages to the upper part of the casing, these passages being governed by a partly
rotating slide which can be turned more or less round by a handle. The vacuum
pipe which extends throughout the train communicates with a circular cavity in the
face of the same slide, and from the facing covered by the slide a number of nozzles
extend up into the upper part of the casing, each of these nozzles being in the
centre of an annular space, which is in communication with one of the steam
passages above mentioned. When the slide is in one position all the steam passages
and apertures of the air nozzles are covered, and in that case there is no expenditure
of steam and no production of exhaust. On turning the handle of the slide a
certain distance one of the steam passages is uncovered, and at the same time the
corresponding air nozzle is also uncovered. The steam then issuing by its passage
causes a current of air from the nozzle and so effects to a certain extent the rarefac-
tion of the air in the communicating pipe and in the brake apparatus connected
with it. By turning the slide farther round two, three, or more of the steam
passages and air nozzles, become uncovered, the rarefaction being thereby rendered
more rapid and complete. The coupling for the communicating pipe from carriage
to carriage consists of two equal and symmetrical nozzles secured to pieces of
flexible tube attached respectively to the air pipe on each carriage. Each of the
nozzles is made with a face having a caoutchouc lip secured to it, the plane of the
face being at an angle of about 45° to the axis of the nozzle, so that when the faces.
of the two parts of the coupling meet the flexible tube on each side hangs in an
easy curve without being strained over an edge of the nozzle. At the lower part of
each nozzle there projects downwards and forwards a curved slotted horn, so
arranged that in bringing the two nozzles together face to face these horns interlace
with one another, keeping the two parts of the coupling steadily in position
relatively to one another. There is also on each part of the coupling a blade spring
which latches over a curved rib on the other part, but not so firmly as to prevent
the two parts from being separated by a forcible pull. The jointing of the faces of
the couplings is kept tight by the external pressure of the atmosphere forcing their
caoutchouc lips together. To the upper side of each nozzle there is jointed a flap,
which when the coupling is disconnected drops down and covers the face of the
nozzle, and being forced by the atmospheric pressure against the caoutchouc lip
closes the nozzle like a valve. The brake cylinder is fitted with a piston packed
by a cup leather, and the piston rod passes through a stuffing box in which is a
ring of leather, caoutchouc, or other suitable packing material, the said ring being
enclosed in an annular cavity from which one or more holes open to the air, so that
the ring is caused by the external atmospheric pressure to grasp the piston rod. A
ring of packing is also provided on the inner face of the cylinder cover or on the
front face of the piston so that when the piston rod is protruded to its full extent from
the cylinder (which is its position when the brakes are off) the piston seats against
this ring of packing, thereby preventing leakage round the piston rod. Behind the
piston the back part of the cylinder is extended to a considerable depth, or is in
communication with a vessel of considerable capacity, providing what may be
termed a vacuum reservoir. At the side of the cylinder near its front end is a
valve box, with the back part of which the communicating pipe is connected by a
branch pipe, preferably provided with a stop cock, so that the cylinder can, when
desired, be excluded from action. In the valve box is fitted a sliding piston, which
covers a port leading to the back part of the cylinder, and which slides on a central
stem connected to a valve that covers an opening to the outer air. This valve is
pressed to its seat by a spring, and its stem which passes through the sliding piston
has parts of its sides grooved or flattened so that in certain positions of the sliding
piston there is passage for air through its central bore. When a partial vacuum is
formed in the communicating pipe the sliding piston moves backwards, giving
passage for air through its bore, and at the same time uncovering the passage to

page_text: the back end of the brake cylinder. The air flows from the cylinder and the
reservoir connected with it until their contents become rarefied to the degree
determined by the exhaustion of the pipe, and the brake piston is kept in its
forward position by the weights or springs that take off the brakes. When it is
desired to put on the brakes air is admitted into the communicating pipe, raising
the pressure therein, By this pressure the sliding piston is forced forwards so as to
close the passage through it and cover the port leading to the back end of the brake
cylinder. In being thus pressed forwards the sliding piston bearing against a collar
on the valve stem pushes the valve from its seat, and air thereupon enters the
valve box and passes thence by a port to the front end of the brake cylinder, so
that the pressure on the front face of the piston is made to exceed that behind it,
and the piston being thus forced back acts on the brake levers with which it is
connected, causing the brakes to be applied. It is obvious that whether air be
admitted purposely or accidentally to the communicating pipe this action will
ensue, and thus when a pipe is broken or when a train separates so that the pipe
becomes opened the brakes will be automatically applied. In order to provide for
restoring the balance of pressure on the two sides of the brake piston a small chase
or groove is formed in the side of the valve box leading to the port communicating
with the back part of the cylinder, so that when the sliding piston remains for a
considerable tine in its forward position, closing that port, there is passage by this
groove for a slow leakage of air into the back part of the cylinder, by which the
pressure therein is gradually raised. Thus when a train has been stopped by the
application of the brakes, as in a station yard, and there is no longer any means of
rarefying-the-air-in-the-pipe-the-pressure on both sides of the brake pistons will
become gradually equalised, and the brakes will be released by the action of their
counterweights or springs.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Imray in the Great Seal Patent Office on the 10th June
1879.
JOHN IMRAY, of Southampton Buildings, in the County of Middlesex. "IM-
PROVEMENTS IN VACUUM BREAKS FOR RAILWAY TRAINS." A communication from
abroad by Joseph Hirsch, of Cologne, in the German Empire..
This Invention relates to the working of the breaks of a railway train by means
of atmospheric pressure acting against a partial vacuum on pistons connected to the
break levers, the partial vacuum being produced by the exhausting action of steam
jets, and the reduction of pressure being communicated throughout the train by a
pipe coupled from carriage to carriage, and connected by branch pipes to the several
break cylinders. The present improvements apply to several parts of the apparatus,
namely, the arrangement of the steam jets for rarefying, the coupling of the pipes
from carriage to carriage, and the break cylinder and its valves. Although the
several improved portions of the apparatus may with most advantage be used in
combination, some of them may be employed without the others; for example, the
couplings and the arrangement of break cylinders may be employed in cases where
the partial vacuum is produced in any known manner, and the jet apparatus may
be used for exhaustion when couplings and break cylinders of known construction
are employed in the working of vacuum breaks. The improved exhaust apparatus
is arranged in such a manner that the amount of rarefaction produced by it can be
readily varied, as well as the rapidity with which the exhaustion is effected, so as
to suit different condition in the working of the breaks by affording means of
quickly producing a considerable amount of rarefaction when it is desired to apply
the breaks speedily and strongly, or of simply maintaining the rarefied condition
of the apparatus so as to provide against leakage. For this purpose steam from the
engine boiler is admitted into the lower part of a casing, from which there are
several passages to the upper part of the casing, these passages being governed by
a partly rotating slide, which can be turned more or less round by a handle. The
vacuum pipe, which extends throughout the train, communicates with a circular
cavity in the face of the same slide, and from the facing covered by the slide a
number of nozzles extend up into the upper part of the casing, each of these nozzles
being in the centre of an annular space which is in communication with one of the
steam passages above mentioned. When the slide is in one position all the steam
passages and apertures of the air nozzles are covered, and in that case there is no
expenditure of steam and no production of exhaust. On turning the handle of the
slide a certain distance one of the steam passages is uncovered, and at the same
time the corresponding air nozzle is also uncovered. The steam then issuing by its
passage causes a current of air from the nozzle, and so effects to a certain extent
the rarefaction of the air in the communicating pipe and in the break apparatus
connected with it. By turning the slide farther round two, three, or more of the
steam passages and air nozzles become uncovered, the rarefaction being thereby
rendered more rapid and complete. The coupling for the communicating pipe from
carriage to carriage consists of two equal and symmetrical nozzles secured to pieces
of flexible tube attached respectively to the air pipe on each carriage. Each of the
nozzles is made with a face having a caoutchouc lip secured to it, the plane of the
face being at an angle of about 45° to the axis of the nozzle, so that when the faces
of the two parts of the coupling meet the flexible tube on each side hangs in an
easy curve without being strained over an edge of the nozzle. At the lower part of
each nozzle there projects downwards and forwards a curved slotted horn so arranged
that in bringing the two nozzles together face to face these horns interlace with one

page_text: another, keeping the two parts of the coupling steadily in position relatively to
one another. There is also on each part of the coupling a blade spring, which
latches over a curved rib on the other part, but not so firmly as to prevent the two
parts from being separated by a forcible pull. The jointing of the faces of the
couplings is kept tight by the external pressure of the atmosphere forcing their
caoutchouc lips together. To the upper side of each nozzle there is jointed a flap,
which, when the coupling is disconnected, drops down and covers the face of the
nozzle, and being forced by the atmospheric pressure against the caoutchouc lip
closes the nozzle like a valve. The break cylinder is fitted with a piston packed
by a cup leather, and the piston rod passes through a stuffing box, in which is a
ring of leather, caoutchouc, or other suitable packing material, the said ring being
enclosed in an annular cavity, from which one or more holes open to the air, so that
the ring is caused by the external atmospheric pressure to grasp the piston rod. A
ring of packing is also provided on the inner face of the cylinder cover or on the
front face of the piston, so that when the piston rod is protruded to its full extent
from the cylinder (which is its position when the breaks are off), the piston seats
against this ring of packing thereby preventing leakage round the piston rod.
Behind the piston the back part of the cylinder is extended to a considerable depth,
or is in communication with a vessel of considerable capacity, providing what may
be termed a vacuum reservoir. At the side of the cylinder near its front end is a
valve box, with the back part of which the communicating pipe is connected by a
branch pipe, preferably provided with a stop cock, so that the cylinder can when
desired be excluded from action. In the valve box is fitted a sliding-piston,-which-
_covers-a-port-leading to the back part of the cylinder, and which slides on a central
stem connected to a valve that covers an opening to the outer air. This valve is
pressed to its seat by a spring, and its stem, which passes through the sliding piston,
has parts of its sides grooved or flattened, so that in certain positions of the sliding
piston there is passage for air through its central bore. When a partial vacuum is
formed in the communicating pipe the sliding piston moves backwards, giving
passage for air through its bore, and at the same time uncovering the passage to the
back end of the break cylinder. The air flows from the cylinder and the reservoir
connected with it until their contents become rarefied to the degree determined by
the exhaustion of the pipe, and the break piston is kept in its forward position by
the weights or springs that take off the breaks. When it is desired to put on the
breaks air is admitted into the communicating pipe, raising the pressure therein.
By this pressure the sliding piston is forced forwards so as to close the passage
through it, and cover the port leading to the back end of the break cylinder. In
being thus pressed forwards, the sliding piston bearing against a collar on the valve
stem pushes the valve from its seat, and air thereupon enters the valve box and
passes thence by a port to the front end of the break cylinder, so that the pressure
on the front face of the piston is made to exceed that behind it, and the piston
being thus forced back acts on the break levers with which it is connected, causing
the breaks to be applied. It is obvious that whether air be adinitted purposely or
accidentally to the communicating pipe this action will ensue, and thus when the
pipe is broken, or when a train separates so that the pipe becomes opened, the
breaks will be automatically applied. In order to provide for restoring the balance
of pressure on the two sides of the break pistons, a small chase or groove is formed
in the side of the valve box leading to the port communicating with the back part
of the cylinder, so that when the sliding piston remains for a considerable time in
its forward position, closing that port, there is passage by this groove for a slow
leakage of air into the back part of the cylinder, by which the pressure therein is
gradually raised. Thus when a train has been stopped by application of the breaks,
as in a station yard, and there is no longer any means of rarefying the air in the
pipe, the pressure on both sides of the break pistons will become gradually
equalised, and the breaks will be released by the action of their counterweights or
springs.

page_text: ESCRITTIVA
Fig. 1 represents a vertical section, and Fig. 2 a side view of an adjustable ejector
according to this Invention; Figs. 3 and are sectional plans respectively on the
lines X, X, and Y,,Y, of Fig. 1. Within a casing C is fixed a ring D through
which are formed several passages a of various sizes terminating in nozzles
projecting from the upper side of the ring. There are also lateral grooves s cut in
the ring, each opening up into a circular space surrounding one of the nozzles. A
rotating slide A, having a middle cavity E and a part cut off its external lip, bears
against the lower face of the ring D, and can be turned more or less round by a
handle B so as to make communication between the lower cavity G of the casing
and one or more of the grooves s, and at the same time to make communication
between the central cavity H and one or more of the passages a. The cavity G
communicates by a pipe with the boiler, and the cavity H communicates with the
break pipe which extends throughout the train. Steam issuing from G by one or
more of the grooves & causes currents of air to issue from H by the corresponding
passage a, thus reducing the pressure of air in the break pipe. When there is
required a small and slow rarefaction in the pipe, such as may be necessary to meet
slight leakages into it, the handle B is turned so as to open the communications
with only one set of the passages a and s. When greater or quicker rarefaction is
required the handle B is turned farther round bringing two sets of the passages a
and s into play; and in order to produce full and rapid exhaust of the break pipe
the handle may be turned still farther round so as to bring all the passages a and s
into play. Fig. 5 represents a half elevation and half section, Fig. 6 a face view,
and Fig. 7 a half plan of a coupling according to this Invention for connecting the
break pipe from carriage to carriage throughout the train. The two half couplings
are equal and symmetrical, each having an oblique nozzle connecting it by a piece
of flexible tube H to the end of the fixed pipe on the carriage. Each half coupling
also has a caoutchouc lip E, which are caused by the external pressure to make a
tight joint when the two half couplings are pressed together. A spring F on the
side of each half engaging over the rib of the other half keeps the halves steadily
together, but yields, allowing them to separate when they are accidentally or
purposely pulled apart. Also, each half coupling has at its lower edge a curved
horn C, which, in the act of coupling, is inserted in a hole D in the opposite half,
whereupon by a canting movement the halves are brought together face to face.
Each half is also provided with a flap G hinged on its upper side, which, when the
couplings are separated, can be turned down against the lip E so as to close the
mouth of the pipe. Fig. 8 represents a half section and half elevation of the break
cylinder and its piston and operating valve, constructed and arranged according to
this Invention. The upper end of the cylinder eommunicates by a pipe K with a
vacuum chamber (which should have a capacity considerably exceeding that of the
cylinder itself), and also by a side passage with a port N. The lower end of the
cylinder has a port O. The ports N and O open into a cylindrical cavity filled
with a piston slide L, and communicating at its upper end with the break pipe
extending throughout the train, and at its lower end with the outer air by a passage
filled with a valve M which is pressed to its seat by a spring. The stem m of the
valve M has a collar on it against which the piston L bears, and the part of the
stem which passes through the piston is grooved or flattened at the sides for part
of its length, so that when the piston L moves a certain distance up from the collar
there is passage for air through it. The main piston of the break cylinder is
provided at its edge with a cup leather packing, and at its middle when it is down,
as shewn in Fig. 8, bears against a leather or caoutchouc washer I so as to prevent
escape of air past the piston rod, which moreover passes through packing rings J of
leather or caoutchouc exposed on their outside to the pressure of the atmosphere

page_text: stem m.
admitted to act on them through holes in the outside casing of the stuffing box.
At the lower edge of the port N there is a small chase or groove n forming a small
air passage between the port N and the lower part of the slide casing. The break
cylinder thus arranged, being connected at K with a vacuum chamber, and at P
with the pipe communicating throughout the train, operates in the following
manner-The air in the pipe P being rarefied by the use of the ejector above
described, or by means of any known ejector or pump, the piston L ascends until
there is passage for air through it along the grooves or flattened parts of the valve
The valve M remaining closed the air in the break cylinder and also in
the vacuum chamber communicating with it at K becomes rarefied, and the pressure
on both sides of the break piston being equally reduced the piston is kept in its
lowest position, as shewn in Fig. 8, by a weight or spring holding the breaks off.
When it is desired to put on the breaks air is admitted to the break pipe P, raising
the pressure therein. The piston slide Lis thus caused to descend closing the
passage through it by the grooves or flats of the stem m, and also covering the
port N. Being still farther pressed down, bearing on the collar of the stem m, it
presses open the valve M, whereupon air from outside rushes into the slide casing,
and thence by the port O under the break piston which it forces upwards, thereby
causing the putting on of the breaks, which are connected in the usual way to the
piston rod. As this will be the result whether air be admitted purposely or acci-
dentally into the communicating pipe P the breaks will be applied in case of that
pipe being opened at any part of its length by a fracture or by the separation of
the train. In order to take off the breaks the air in the pipe P is_again_rarefied,-
_the_valve-M-closes,-and-the-pressure on the underside of the piston becoming again
reduced to equality with that on its upper side, the piston is caused to descend by
the weight or spring taking off the breaks. In operating with this apparatus the
breaks can be put on gently and gradually if desired, or suddenly and with full
force, according to the rapidity with which air is admitted into the pipe P by means
of a cock or valve at any part of its length worked by the engine driver or guard.
Moreover, as the air which presses on the underside of the piston enters imme-
diately at each break cylinder by the opening of its valve M, and has not to travel
through any length of pipe, all the breaks throughout the train become applied
immediately and simultaneously by increasing of the pressure in the pipe P. The
chase or groove n serves as a small air passage by which the pressures on both sides
of the break piston become equalised, while the piston slide L remains in its normal
position, as shewn in Fig. 8. But this passage is so small that when there is a
rapid or considerable change of pressure effected by the opening of the valve M for
the purpose of putting on the breaks there is no time for air to pass by n to the
upper end of the cylinder in such quantity as to cause any appreciable increase of
pressure on the upper side of the piston.
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
hereby declare that I make no general claim to the working of breaks on railway
trains by excess of atmospheric pressure over that of rarefied air acting on pistons
connected to the breaks, nor to the use of a steam ejector for the purpose of
rarefying the air in a pipe communicating throughout the train; nor generally to
separable couplings for connecting the said pipe from carriage to carriage; but I
claim,―
First. The construction of adjustable steam ejector having several ejecting nozzles
combined within one casing and governed by a rotating slide, so that one, two, or
more may be brought into action, according to the amount and rapidity of the
rarefaction desired to be effected, substantially as herein described with reference
to Figs. 1, 2, 3, and 4 of the accompanying Drawings.
Second. The construction of coupling herein described with reference to Figs. 5,
6, and 7 of the accompanying Drawings.
Third. The use in combination with a break cylinder, with its ports, break

page_text: piston, vacuum chamber, and communicating pipe, of the piston slide L and
valve M, constructed and operating substantially as herein described with reference
to Fig. 8 of the accompanying Drawings.
In witness whereof, I, the said John Imray, have hereunto set my hand and
seal, this Tenth day of June, in the year of our Lord One thousand eight
hundred and seventy nine.
JOHN IMRAY. (LS.)