IMPROVEMENTS IN FLEXIBLE TUBES OR HOSE FOR AIR BRAKES AND OTHER PURPOSES
Year: 1884

page_text: I, JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of said Invention for "IMPROVEMENTS
IN FLEXIBLE TUBES OR HOSE FOR AIR BRAKES AND OTHER PURPOSES" to be as
follows:-
This Invention relates to the flexible tubes or rubber hose used in connection
with Westinghouse air brakes or other air brakes and to tubes or hose generally
for conveying fluids and the said Invention consists in the combination of an inner
and an outer flexible tube or rubber hose with a coupling or other attachment
adapted to be secured to both tubes or hose, the object of this feature of the
Invention being to lessen the liability to accidents and delays due to the bursting
of the single tubes or hose heretofore used, more particularly in connection with air
brakes.
The said Invention further consists in combining the duplex tube and coupling
or attachment with a signalling device or tell-tale for notifying the inspector of the
air brakes, or other apparatus to which the Invention may be applied when a
leakage in the inner tube takes place.
The coupling or attachment may be of any ordinary construction used in air-
brakes with this exception that the tubular stem or tail-piece of the coupling
according to this Invention is constructed for attachment to an outer flexible tube
or hose and an inner flexible tube or hose, the stem having an enlargement to
which the end of the outer tube is tightly fitted and secured by wire wrappings or
otherwise, while the stem is reduced in diameter to receive the end of the inner
tube.
b
The tubes or hose themselves may be made in the same manner and of the same
materials as those in common use for air brakes but it is preferred to make the
inner hose non-expansible, so that as long as this inner hose is in service there will
be no strain on the outer one, and the latter remains unimpaired.
The relative diameters of the two flexible tubes should be such that the inner
tube can be pulled freely through the outer tube, and it is preferred to make the
diameters such that there shall be an annular space between the two, although the

page_text: interior of the outer tube may be close to the exterior of the inner tube that the
latter will be capable of resisting a greater internal pressure than it could in
the absence of the outer tube.
The outer tube, however (which it is preferred to make thicker and stronger
than the inner tube) is intended not so much as a backing for the latter as a
provision against accidents to the inner tube, for should the latter leak there can
be no cessation of the action of the air brakes for the outer tube which then comes
into service is comparatively unimpaired and forms a perfect substitute for the
injured inner hose.
When the tube or rubber hose of an air brake bursts, the brakes must be
operated by hand or there must be a stoppage of the train of Cars until the
damaged tube or hose can be replaced by a new one but it is preferred to combine
with the duplex tube a signalling device, which will serve to notify the attendants
that the inner tube is leaking, the train however may pursue its course, the air
brakes being in a condition to perform their duties, through the outer tube until
the train reaches its destination or other point where repairs can be made.
Different kinds of signals may be adopted for instance, a small tube may be
driven into a hole in the coupling, the said tube communicating with the annular
space between the two hose. A sliding rod fits into the tube sufficiently tightly to
retain its place therein in the absence of any air under pressure in the space
between the two hose, but should the inner tube leak, the rod will be pushed out
against a shoulder and this will be a signal that repairs will be required.
The signal may consist of a plate painted some conspicuous colour so as to be
readily seen, this plate having an arm through an elongated slot in which passes a
pin into a projection on the coupling, the plate being hung to a rod provided with
a piston adapted to the aforesaid tube.. A spiral spring surrounding the rod tends
to force the piston inward, and to maintain the plate in its normal position but
when, owing to the leakage of the inner tube, there is a pressure of air in the
annular space between the two tubes, the piston will be forced outward in the tube
and the plate will project outward thereby notifying that there is a leakage in the
inner tube.
Many other and different known signalling devices will readily suggest
themselves, hence in this part of my invention I do not restrict myself to the
devices described.
To facilitate the securing of the two hose to the attachment, it is preferred to
make the latter in two parts the portion of the tail-piece or stem to which the
inner hose is secured being adapted to be screwed into the outer portion-The
inner hose is first secured to its portion of the stem and is then drawn with the
latter into the outer tube and screwed into the outer portion of the attachment or
tail piece and the end of the outer hose is then wired or otherwise secured to the
latter.
The Invention is especially applicable to air-brake couplings but it may be
applied to various other apparatus in which rubber hose or flexible tubing is used
for the conveyance of fluids, and the attachment instead of being in the form of a
coupling may be specially constructed simply to receive the ends of the two flexible
tubes and if desired a signaling device also.

page_text: I JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention for "IMPROVEMENTS
IN FLEXIBLE' TUBES OR HOSE FOR AIR BRAKES AND OTHER PURPOSES
"and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:—
This Invention relates to the flexible tubes or rubber hose used in connection
with Westinghouse air brakes or other air brakes and to tubes or hose generally for
conveying fluids, and the said Invention consists in the combination of an inner
and an outer flexible tube or rubber hose with a coupling or other attachment
adapted to be secured to both tubes or hose, the object of this feature of the
Invention being to lessen the liability to accidents and delays due to the bursting
of the single tubes or hose heretofore used, more particularly in connection with
air brakes. There may with advantage be combined with the duplex tube and
coupling or attachment, a signalling device or tell-tale for notifying the inspector
of the air brakes or other apparatus to which the Invention may be applied, when
& leakage in the inner tube takes place.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of drawings the same letters of reference
indicating corresponding parts in all the figures.
I will explain the Invention as applied to an air brake.
Figure 1 is a longitudinal section of the duplex flexible tube for air brakes with
a portion of one of the couplings.
Figure 2 is a transverse section taken on the line 1-2 Figure 1.
Figure 3 is a transverse section taken on the line 3-4 Figure 4.
Figure 4 is a view illustrating the combination of the duplex tube with a
signalling device or tell-tale.
Figures 5 and 6 are enlarged sectional views of signalling devices suitable for
use with the duplex tubes and Figure 7 is a sectional view illustrating a method of
applying the coupling or attachment to the two tubes or hose.
The coupling or attachment A may be of any ordinary construction used in air
brakes with this exception that the tubular stem or tail piece of the coupling
according to this Invention is constructed for attachment to an outer flexible tube
or hose B and an inner flexible tube or hose B' the stem having an enlargement a
to which the end of the outer tube is tightly fitted and secured by wire wrappings
or otherwise while the stem is reduced in diameter at a¹ to receive the end of the
inner tube which is properly secured as indicated in the drawing.
The tubes or hose themselves may be made in the same manner and of the same
materials as those in common use for air-brakes but it is preferred to make the
inner hose non expansible so that as long as this inner hose is in service there will
be no strain on the outer one and the latter remains unimpaired.
:
The relative diameters of the two flexible tubes should be such that the inner
tube can be pulled freely through the outer tube and it is preferred to make the
diameter such that there shall be an annular space between the two although the
interior of the outer tube may be close to the exterior of the inner tube that

page_text: the latter will be capable of resisting a greater internal pressure than it could in
the absence of the outer tube.
The outer tube however (which it is preferred to make thicker and stronger than
the inner tube) is intended not so much as a backing for the latter as a provision
against accidents to the inner tube for should the latter leak there can be no
cessation of the action of the air brakes for the outer tube which then comes into
service is comparatively unimpaired and forms a perfect substitute for the injured
inner hose.
When the tube or rubber hose of an air brake bursts the brakes must be operated
by hand or there must be a stoppage of the train of cars until the damaged tube or
hose can be replaced by a new one but it is preferred to combine with the duplex
tube a signalling device which will serve to notify the attendants that the inner
tube is leaking, the train however may pursue its course, the air brakes being in a
condition to perform their duties, through the outer tube until the train reaches its
destination or other point where repairs can be made.
I do not limit myself to any particular signalling device as it in itself alone is
not separately claimed under this Invention I give the following as examples of
devices suited for combination with the duplex tubes aforesaid. A small tube D is
driven into a hole in the coupling as shewn in Figure 4 and more clearly in the
enlarged view Figure 5 the said tube communicating with the annular space
between the two hose. A sliding rod F fits into the tube sufficiently tightly to
retain its place therein in the absence of any air under pressure in the space
between the two hose but should the inner tube leak the rod will be pushed out
against the shoulder and this will be a signal that repairs will be required.
The signal may consist of a plate W painted some conspicuous colour so as to be
readily seen, this plate having an arm w (Figure 6) through an elongated slot in
which passes a pin n into a projection on the coupling the plate being hung to the
rod F provided with a piston adapted to the tube D-A spiral spring surrounding
the rod tends to force the piston inward and to maintain the plate W in the
position shewn by dotted lines, but when owing to the leakage of the inner tube
there is a pressure of air in the annular space between the two tubes the piston
will be forced outward in the tube D and the plate W will project outward as
shewn by plain lines in figure 6 thereby notifying that there is a leaking in the
inner tube.
I do not however restrict myself to these devices as any suitable signalling
device may be employed.
To facilitate the securing of the two hose to the attachment A, it is preferred to
make the latter in two parts as shewn in Figures 1 and 7 the portion E of the
tail-piece or stem to which the inner hose is secured being adapted to be screwed
into the outer portion A'-The inner hose is first secured to its portion of the
stem and is then drawn with the latter into the outer tube and screwed into the
outer portion of the attachment or tail piece and the end of the outer hose is then
wired or otherwise secured to the latter:
The Invention is especially applicable to air brake couplings but it may be
applied to various other apparatus in which rubber hose or flexible tubing is used
for the conveyance of fluids and the attachment A¹ instead of being in the form
of a coupling may be specially constructed simply to receive the ends of the two
flexible tubes and if desired a signalling device also.
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:-
First The combination of an inner and an outer flexible tube for air brakes or
other purposes, with an attachment having a tubular stem or tail piece, to which
bath tubes sensed substantial harainhofore desesibed

page_text: Second-The combination of an inner and outer tube for air brakes or other
purposes, and a stem or tail piece constructed for attachment to both tubes, with
a signalling device actuated by air or other fluid under pressure which may gain
access to the annular space between the two tubes, substantially as herein
before described.