Improvements in and connected with Inflatable Wheel-tyres.
Year: 1893

page_text: Date of Application, 23rd Sept., 1893
Complete Specification Left, 23rd June, 1894-Accepted, 22nd Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements in and connected with Inflatable Wheel-tyres.
I, ANTHONY PULBROOK, of Eastcheap Buildings, Eastcheap, in the City of
London, Solicitor, do hereby declare the nature of the said invention to be as
follows:-
This invention relates to the inflatable wheel tyres of bicycles, tricycles and
other carriages, and its object is, firstly, to provide improved means for preventing
the puncturing of the inflatable tube; secondly, to provide an improved arrangement
of the inner or reserve tube, when such is employed, whereby the chance of
puncturing such inner or reserve tube is materialy reduced; thirdly, to provide
means for the prevention of endosmosis or of dialysis in the reserve or other inflatable
tube; and, fourthly, to provide improved means of securing the outer envelope of
the tyre to the rim of the wheel.
The improved means for preventing the puncturing of the inflatable tube consist
in making such tube laminated, that is to say with several tubes inside one another,
and with bands of bladder, gold-beaters' skin, raw hide, tanned hide, celluloid, or
other more or less unpuncturable material interposed between them, or some of
them, at such parts as are likely to be punctured by sharp substances over which
the wheel may pass. With this construction of inflatable tyre a sharp substance,
such as the point of a nail for example, may pass through one or two of the
outer tubes and bands, but as it gets nearer to the inner tube the band of more
or less unpuncturable material will yield rather than be punctured, and will press
the inner tube or tubes inwards, thereby protecting it or them from being
punctured.
The improved arrangement of inner or reserve tube consists in the employment
of an outer air tube which is enclosed in and covered by the usual envelope and
has inserted within it two inflatable tubes, each provided with its inflating valve.
One of these internal tubes is placed in that part of the outer air tube which
comes next to the rim of the wheel and is the reserve tube proper and the other
internal tube is placed in that part of the outer air tube which comes next to the
tread of the tyre and is the inflatable tube proper. The latter of the two internal
tubes is that which is preferably first inflated, and when inflated it forces the
reserve tube radially inwards towards the rim of the wheel so that the said reserve
tube is protected from a puncturing substance not only by the thickness of the
envelope and the beforementioned outer air tube, but by the two thicknesses of the
inflated tube and the thickness of the stratum of air in such tube. Furthermore
when the inflatable tube proper has been so badly punctured that it is no longer of
any practical use as an inflatable tube, and the reserve tube has been inflated in order
to take its place, the said reserve tube is still protected from being punctured by
the two thicknesses of the deflated tube, the thickness of the outer air tube, and
the thickness of the envelope.
In some cases I provide means whereby communication may be established
between the two inflatable tubes so as to maintain the same pressure of air in both,
until one of them is punctured when the communication may be closed and the
other tube fully inflated and used in place of the damaged one.
In the arrangements heretofore in use where a reserve tube is inserted within
the inflatable tyre, the reserve tube, when inflated, is only protected against
puncture by the thickness of one side of the inflatable tyre and the thickness of the
envelope, that is to say by two thicknesses of india rubber, whereas in my arrangement
it is protected by four thicknesses of rubber.

page_text: In cases where laminated tubes are used, the reserve tube may be interposed
between the two inner tubes where they come against the rim.
The means for preventing endosmosis or dialysis in the reserve or other inflatable
tubes consists in enclosing such tubes in an envelope or covering of oiled silk or
other suitable flexible and impermeable material which will not allow of the passage
of air or gas through it by the action of endosmosis or dialysis. This impermeable
envelope or covering is preferably made of such a size that when the tube within it
is inflated the said envelope or covering shall not be materially stretched by such
inflation, because if it were it might in some cases be liable to tear, and its effect
would thereby be nullified. When the inflatable tube is enclosed in an envelope or
covering of the kind above described, it is shielded thereby from contact with the
air or gas external to it and the actions of endosmosis and dialysis are effectually
prevented.
The improved means of securing the outer envelope of the tyre to the rim of the
wheel consist of the following devices :-One side of the rim of the wheel is
corrugated or grooved circumferentially, and these corrugations are or may be
lined internally with indiarubber or other suitable material to produce a good
holding surface. One edge of the outer covering is formed with corrugations or
grooves corresponding to those on the rim and the envelope is cemented into the
rim with this corrugated edge left free and facing the corrugations of the rim.
The other edge of the envelope, after being passed over the inflatable tube, is passed
in between the corrugations or grooves on the rim and those on the other edge of
the envelope and is secured at intervals to the rim by means of studs or hooks
taking into holes therein, or by other means. When the tyre tube is inflated, its
side presses the corrugated or grooved edge of the envelope outwards against the
other edge of the envelope and presses such edge into the corrugations or grooves
in the rim whereby it is held securely between the two sets of corrugations by the
pressure of the air in the inflated tyre.
Dated this 23rd day of September 1893.
A. PULBROOK,
Per W. H. Beck,
115, Cannon Street, London, E.C., Agent.
COMPLETE SPECIFICATION.
Improvements in and connected with Inflatable Wheel-tyres.
1, ANTHONY PULBROOK, formerly of Eastcheap Buildings, Eastcheap, in the
City of London, but at present of 14 Victoria House, South Lambeth Road, in
the County of Surrey, Solicitor do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, reference being had to the
accompanying sheet of drawings and to the letters and figures marked thereon,
that is to say :-
This invention relates to the inflatable wheel tyres of bicycles, tricycles, and
other carriages, and its object is firstly to provide improved means for preventing
the puncturing and deflation of the inflatable tube; secondly to provide an
improved arrangement of the inner or reserve tube, when such is employed,
whereby the chance of puncturing such inner or reserve tube is materially reduced,
and thirdly to provide means for the prevention of endosmosis or of dialysis in the
reserve or other inflatable tube.
The improved means for preventing the puncturing of the inflatable tube consists
in making such tube laminated, that is to say with several tubes inside one another,
and with bands of bladder, gold-beaters' skin, raw bide, tanned hide, celluloid, or
or other more or less unpuncturable material interposed between them or some of

page_text: them at such parts as are likely to be punctured by sharp substances over which
the wheel may pass.
With this construction of inflatable tyre a sharp substance,
such as the point of a nail for example, may pass through one or two of the outer
tubes and bands; but as it gets nearer to the inner tube the band of more or less
unpuncturable material will yield rather than be punctured, and will press the
inner tube or tubes inwards thereby protecting it or them from being punctured.
1 seek to form the tyre as much as possible of air, avoiding all thick substances
both in the tread and otherwise. As a material by itself, solid indiarubber is one
of the most resilient known; but a tyre built up of compressed air and layers of
a tough flexible but thin material will be lighter and more resilient, as evidenced
by the extreme resilience of celluloid air balls. I therefore make the air tube
laminated, and prefer to substitute for the thickened tread of indiarubber, commonly"
used as an outer cover (when an outer cover is used) a laminated cover constructed
in a manner similar to that hereinafter described with respect to the air tube. I
construct the air tube or tyre proper as follows:-
In the accompanying drawings
Figure 1 shows a section of my improved tyre before inflation, Figure 2 a section
of the same tyre after inflation, Figure 3 a section of the same tyre partially
perforated by a mail, Figure 4 a longitudinal section and Figures 5 and 6 are
sections showing my improvement with reference to the reserve tube or tubes.
I construct the air tube or tyre of two or more tubes A, B, C, (see Figures 1, 2, 3
and 4) of indiarubber placed one inside the other, each tube being of smaller
diameter than the next outer one surrounding it, so as to leave an air space
between each two adjacent tubes or laminations. The inner tube A is preferably
made of thinner material than the outer ones so as to create as little resistance as
possible to the pressure of the air in that tube being transmitted, as hereinafter
described, to the air confined in the air spaces between the tubes, and also to offer
as little resistance as possible to any puncturing material striking the tyre from
outside. The usual charging valve (not shown in the drawings) passes through
the rim of the wheel and through all the tubes, and opens into the innermost
tube A. The two ends of each tube forming a lamination are connected together
airtight so that each tube is complete in itself, and has no communication with the
interior of the adjacent tube. I sometimes provide transverse ridges or distance
pieces D (see Figure 4) between the several laminations to assist in maintaining
the air space between them.
When air, or other elastic fluid, under pressure, is introduced into the inner
tube A the latter expands as shown in Figure 2 and compresses the air in the
space between it and the next outer tube or lamination B, the latter expands in
turn, and compresses the air in the space between it and the next outer tube or
lamination C, and so on for as many tubes or laminations as there may be. The
inner tube or lamination A, although made of very thin india rubber, being
supported by the surrounding laminations, and the compressed air between them,
will have all the strength of those surrounding laminations to enable it to withstand
the pressure of the compressed air contained within it without bursting.
With a laminated tyre thus formed the effect of a blow on the outer part of the
tyre is to a large extent neutralised and expended before it reaches the inner tube,
because each layer of compressed air acts as a cushion to receive and distribute
the energy of the blow, thereby rendering the next succeedling lamination less
liable to injury. Besides this, each lamination, except the outermost, being subject
to the pressure of compressed air on both sides is more or less in equilibrium and
consequently yields or gives way before pressure from outside more readily than
a tube subjected to the internal pressure only of compressed air. This yielding or
readiness to give way before pressure is a great preservative against puncture,
because a substance can only be punctured when it offers a sufficient amount of
resistance to prevent the puncturing object pushing the substance before it instead
of penetrating it.
A tyre thus formed solely of indiarubber would expand to a great size and would

page_text: ultimately burst if the pressure were increased to a sufficient degree; consequently
it is necessary to provide an outer casing of as non-stretchable material as will
keep the indiarubber within bounds and prevent it from bursting. This may be
accomplished by employing a thick outer covering of indiarubber or of indiarubber
and canvas, but this thick cover, whilst it allows for wear and tear, affects the
resilience. I therefore endeavour to make the outside cover of as thin and tough
material as possible not only for the purpose of carrying out one of the fundamental
principles of my invention, namely the allowing in every possible manner for the
material giving or yielding to a blow, and reacting with the pressure of the
compressed air, but also to afford means of bringing the most resilient part of
the tyre, namely the compressed air, as near as possible to the outside tread of
the tyre which not only preserves the covering from wear by virtue of its resilience,
but reduces vibration. Of all the materials for this purpose with which I am
acquainted, I have found the skins of fishes or amphibious animals to be the most
suitable, although I do not confine myself to this material, as I may use thin
leather such as wamba deer skin, horse hide, the grain part of pig skin, or other
thick leather after the flesh part has been skived or split away. Sometimes I
solution a band or bands of such thin material to the tread part to render it more
lasting and I sometimes solution or cement to the tread part of the tyre a band or
bands of the rough skins of fishes of the spotted dog or other fish of the shark
tribe to prevent slipping, to give a greater grip, and to prevent puncturing by
reason of the peculiar texture of the skin which, instead of having scales, is closely
covered and defended with spines which in substance somewhat resemble horn, and
is even more firm and compact. These spines assist in distributing a blow on its
first reception by the tyre.
In Figures 1, 2, 3 and 4 of the drawings E represents an outer air-tight casing
composed of fish-skin as above mentioned or other suitable thin and tough and
practically non-stretching material, whereby the expanding action of the compressed
air is confined to the inner indiarubber tubes or laminations, and has no expanding
effect upon the said outer casing E.
In a tyre formed as above described, after a puncturing substance has penetrated
the outer skin, there would be no puncture-resisting material other than the india-
rubber inner tubes or laminations to withstand its puncturing action. Indiarubber,
when in thin sheets, especially if in a state of tension, offers but little resistance to
puncture by a sharp point, I therefore interpose between the indiarubber tubes or
laminations, especially at the tread parts thereof, bands of more or less unpuncturable
material such as bladder, gold beaters' skin, raw hide, parchment, vellum, vegetable
parchment, thin tanned hide or skin, or split or skived hide, layers of thin fibrous
material such as cotton, silk, heinp and such like (such fibrous material being
preferably quilted to prevent their working up into balls, or sewn between two
layers of thin material and then quilted) and the skins of fishes and amphibious
animals. Such bands are shown at FG and H in Figures 1, 2, 3 and 4 and are
continued longitudinally all round the tyrė, the transverse bands D, when such are
employed, tending to keep such bands of more less unpuncturable material in place.
Being entirely free and loose except where they are pressed to the tubes by the
transverse bands, and the tubes being kept apart by the compressed air between
them, the bands of more or less uupuncturable or protecting material are free to
move, consequently when a puncturing substance, such as a nail for instance, passes
through one or more of the outer bands of protecting material and outer indiarubber
tubes, as shown by way of example in Figure 3 of the drawings, it at last encounters
one of these bands of protecting material which being loose affords insufficient
resistance to enable the puncturing substance to perforate it, but gives or yields
until it reaches the india rubber tube immediately over it. This being pushed as it
were by a considerable surface of the protecting material, yields, and the puncturing
substance does not get through.
On one of the outer tubes or laminations being punctured and the compressed air
between it and the next inner tube or lamination, being thereby permitted to escape,

page_text: the said next indiarubber tube immediately expands by the action of the compressed
air contained within it and fills up the space left by the deflated tube until stopped
by the outer non-stretching casing and thus the air tube still continues inflated for
ue until arrival at a convenient place to repair the puncture, and to restore the full
pressure by pumping in additional air in the usual way.
I sometimes place the more or less non-puncturable material between the surfaces
of grease-proof paper, firstly to prevent oil from the fish skin, when such is employed,.
damaging the indiarubber, and secondly to give smooth surfaces for the skin or other
material to slid upon.
The improved arrangement of inner or reserve tube consists in the employment
f an outer air tube J (see Figures 5 and 6) which is or may be enclosed in, and
covered by, the usual envelope (not shown in the drawing) and has inserted within
it two inflatable tubes K and L preferably made of very thin indiarubber each
provided with its inflating valve. One of these internal tubes K is placed in that
part of the outer air tube . which comes next to the rim of the wheel, and is the
reserve tube proper, and the other internal tube L is placed below it, and constitutes
an inner inflatable tube which forms the inflatable tube or tyre proper, and when
inflated it forces the reserve tube K radially inward towards the rim of the wheel
as shown in Figure 5, so that the said reserve tube is protected from a puncturing
substance not only by the thickness of the envelope by the outer air tube J, by the
two thicknesses of the inflated tube L and by the thickness of the stratum of air in
such tube, but also by being kept away from all puncturing substances of moderate
height. Furthermore when the inflatable tube proper L has been so badly
punctured that it is no longer of any practical use as an inflatable tube, and the
reserve tube K has been inflated in order to take its place, as shown in Figure 6,
the said reserve tube is still protected from being punctured, by the two thicknesses
of the deflated tube L which are then pressed together towards the tread, the
thickness of the outer air tube J and the thickness of the envelope, when the latter
is used.
In the arrangements heretofore in use, where a reserve tube is inserted within the
inflatable tyre the reserve tube when inflated is only protected against puncture by
the thickness of one side of the inflatable tyre and the thickness of the envelope,
that is to say by two thicknesses of indiarubber whereas in my improved arrange-
ment it is protected by four thicknesses of rubber. Moreover in the ordinary
arrangements the reserve tube being loose in the air tube is apt to stretch and get
out of position next the rim, whereas in my arrangement it is always kept close
to the rim when not in use and is fully protected by its position as above
explained.
In cases where laminated tubes are used the reserve tube may be interposed
between the two innermost tubes where they can come against the rim.
Seeing that the tubes of thin indiarubber contain air at a greater pressure than
the air surrounding them the action of endosmosis or dialysis may be set up. To
obviate this I place immediately inside the outer non-stretching tube and outside
the inflatable tube or tubes a tube of very thin material M (see Figure 4) preferably
larger than the outer tube, and made of oiled silk, very thin tanned leather, dog-
skin or other material as little subject to the action of endosmosis or dialysis as
possible. This tube being very thin and slightly larger than the containing tube.
of unstretchable material forming the outer tube is pressed by the compressed air
tightly against it and assists to strengthen it while preventing more or less the
aforesaid action of endosmosis or dialysis.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
First. An inflatable wheel tyre, composed of tubes of indiarubber or other
suitable elastic material placed inside one another, forming laminations, having
flexible material which is more or less unpuncturable, or more or less difficult to

page_text: puncture, interposed in the spaces or in some of them, between the said laminations,
substantially as described, and for the purposes specified.
Second. An inflatable wheel tyre composed of tubes of indiarubber or other
suitable elastic material, placed inside one another, forming laminations, having
flexible material which is more or less unpuncturable, or more or less difficult to
puncture, interposed in the spaces, or in some of them, between the said laminations,
the whole being contained within a flexible tube of practically non-stretchable
material, substantially as described and for the purposes specified.
Third. The arrangement of the inner or reserve tube which consists in enclosing
it, along with the inflatable tube proper, within an outer air tube, in such manner
that the pressure of the compressed air in the said inflatable tube proper, presses
the said reserve tube, when the same is deflated, inwards towards the rim, substan-
tially as described, and for the purpose specified.
Fourth. In inflatable wheel tyres preventing endosmosis, or dialysis by enveloping
the indiarubber or other elastic tube or tubes, containing air or gas under pressure,
in a loose airtight covering of oiled silk, dog-skin, fish skin, or other suitable
impermeable material interposed between the said tube or tubes and the outer non-
stretching tube or cover, substantially as described.
Dated this 23rd day of June 1894.
A. PULBROOK,
Per W. H. Beck,
115, Cannon Street, London, Agent.