Improvements in and connected with Inflatable Tyres for the Wheels of Cycles and other Carriages.
Year: 1894

page_text: Date of Application, 8th Aug., 1894
Complete Specification Left, 8th May, 1895-4ccepted, 3rd Aug., 1895
Improvements in and connected with Inflatable Tyres for the Wheels
of Cycles and other Carriages.
I, ANTHONY PULBROOK, of 14 Victoria House, South Lambeth Road, in the
County of Surrey, Solicitor, do hereby declare the nature of this invention to be
as follows:-
This invention relates to the inflatable or pneumatic wheel-tyres of bicycles,
tricycles, and other carriages.
I make such a tyre of an outer tube of thin non-stretchable flexible material
containing inner tubes of elastic stretchable material, or of non-stretchable material,
or some of the tubes of elastic stretchable material and some of nou-stretchable
material, air spaces being left between each tube. Each inner tube is of smaller
diameter than the next outer tube, and to keep each inner tube apart from the
next outer tube, and to preserve the air spaces between the tubes I surround the
inner tubes at intervals with distance pieces. These distance pieces may be made
of indiarubber or similar elastic material, but I prefer to make them of hollow
rings of indiarubber or other flexible impervious material containing elastic fluid
such as air or gas for example.
An air or gas supply valve sometimes opens into the innermost of the aforesaid
tubes, and when air or gas is forced into such innermost tube, in cases where the
innermost tubes are made of elastic stretchable material, the latter expands and
compresses the air or gas confined in the space between it and the next outer tube
which latter expands in like manner, and compresses the air or gas confined in the
space between it and the next outer tube, and so on until the external tube is
reached and this being practically unstretchable prevents the expansion of the inner
tubes and compressed air or gas beyond certain limits.
I am aware that it has been proposed to employ concentric tubes made of elastic
or compressible material fitting closely to and lying or nested within each other,
but it is an essential and distinctive feature of my invention that the laminations
or tubes should not fit closely one in the other, but that air or gas spaces should
be left between any two adjacent tubes, the air or gas thus confined between the
tubes making the tyre resilient. A tyre, made up of laminations not separated
from each other by air spaces but fitting closely together becomes, by reason of the
pressure of the air in the inner tube, one compact body which, as far as resiliency
is concerned, is little, if at all, different from a solid tyre composed of material
having the same thickness as the aggregate thickness of the laminations.
I am also aware that it has been proposed to employ in a tyre multiple endless
tubular linings loose one within the other and adapted to slightly vary or alter
their relative positious sufficiently to cover a puncture, in the event of such
occurring, the inflation of the tube so formed with linings taking place through a
single air-filling tube which communicates with the internal or central lining,
but it is an essential and distinctive feature of my invention when the inflation
takes place in that manner that the laminations should be of indiarubber or other
elastic material which will stretch or expand under the pressure of the contained

page_text: air or gas and regain their normal size when that pressure is removed, so that each
tube being of a smaller diameter than that surrounding it, air spaces always exist
between any two adjacent tubes. These air spaces would be fatal to the purpose
of covering a puncture as in such a case there would be no loose material to
come in contact with and cover the punctured part and prevent the escape of
air or gas.
It is customary to make tyres of indiarubber at their tread parts immediately
next the ground, and to prevent wear and tear to make that part thicker than the
part next the rim. The thinner the tread part of a tyre is, and the nearer the air
or gas is brought to the ground, the more resilient the tyre is, and consequently
the longer it will wear. I therefore make the outside tread part of the tyre of thin
tough material such as fish skin, seal skin, horse hide, wamba skin, the grain part
of leather, or any tanned or tawed skin of any animal, or of textile material
capable of being rendered air and waterproof by treating it with boiled oil, india-
rubber, gutta percha or balata solution, or by any known flexible varnish or
compound, and inside that I place thin indiarubber with a confined air space
between it and the outside material so that when an expanding air tube is
covered by this outside covering the air in the confined air space is compressed by
the expansion of the said air tube within the covering.
A tyre formed as above described makes a very fast, resilient and light tyre
especially suited for a racing track.
Sometimes effect the compression of air introduced into a tyre at normal
pressure in the following manner :-I first make a tube of indiarubber, indiarubber
compound, thin oiled silk, or other oiled or varnished textile fabric or other
material impervious to air or gas. I fill this with air or gas at or above atmospheric
pressure and close hermetically the aperture through which the air or gas has
been forced in air-tight so as to retain the air or gas in the said tube. At intervals
round the tube I place distance pieces which have a smaller internal diameter than
the tube when the latter is blown out. I then enclose the aforesaid tube with its
distance pieces within another tube made of similar material and similarly fill the
space between the two tubes with air or gas at or above atmospheric pressure,
and I place over this second tube other distance pieces similar to those round the
first tube. Over this second tube I place a third (which I similarly fill with air or
gas) with other distance pieces outside it, and so on to any required extent; then
outside all I place a tube or cover made of non-stretchable material which is
impervious to air or gas.
valve of the usual character. On forcing air or gas under pressure through the
This outer tube or cover is provided with an air inlet
said valve into the said outside tube or cover, that pressure is communicated to the
air or gas in all the interior tubes, and these tubes, being thin and flexible, give
way before the pressure, are more or less collapsed thereby, and are kept away
clear of the range of puncturing materials. In the event of the outside tube or
cover containing the air or gas under pressure being punctured, the air or gas in
the internal tube or tubes regains its normal condition, and the tyre still remains
inflated to a certain extent and can be used until a convenient point is reached for
repairing the puncture in the outer tube or cover. By the compression of the air
inwards against the outer walls of the inner tubes, the said walls, being subjected
to the same pressure of air on both sides, offer little or no resistance, and not
being in a state of tension are less liable to puncture than tubes subjected to an
unbalanced internal pressure.
According to a modification of the last described arrangement I provide each of
the internal tubes with a valve opening inwards so that when air or gas under
pressure is forced into the outer tube or cover it finds its way through the said
valves into the interior of the said internal tubes, and in the event of the outer
tube or cover or even one or more of the internal tubes being punctured, the
valves prevent the escape of the compressed air or gas from the internal tubes
or such of them as may not have been punctured, and they consequently remain
inflated tubes available for use until an opportunity is afforded to repair the

page_text: punctures in those tubes that have become deflated. The inner tubes may be made
of elastic material, or some of them of elastic and some of non-elastic material.
Sometimes I attach, by cement or otherwise, that portion of the inner tube that
comes next to the rim, to some non-stretchable material or to part of the cover
which at this point 1 cement or otherwise fasten to the rim, and I leave the
remainder of the tube loose inside the outer covering, so that on air or gas being
introduced, under pressure, into the outer covering, and between it and the part of
the inner tube hanging loose when not blown out, the air or gas in the inner tube
is compressed and the part of the tube not cemented to the non-stretchable material
is forced up towards the rim, and being a loose piece, having almost equal pressure
on both sides, it is less liable to puncture and yields to a blow.
When the pressure of the air or gas in an inflatable or pneumatic tyre has been
reduced by reason of a puncture therein to atmospheric pressure, the part that
bears on the ground collapses and is chafed by the rim of the wheel. To obviate
this I insert into an inner tube closed airtight segments of tube abutting against
each other end to end, and filled with air or gas. The said inner tube with the
segments in it is enclosed in an outer tube or cover into which air or gas under
pressure is forced through an inlet valve in the usual way. This pressure acts
externally on the inner tube, compressing the air in it and in the segments and
leaving an air space between the outer tube or cover and the inner tube.
the outer tube is punctured the compressed air escapes from it and that in the
inner tube and segments expands causing such tube and segments to fill the outer
tube or cover, and to take the place thereof for the time being until the puncture
can be repaired.
When
When I use india rubber in combination with other material in the construction
of the tubes, 1 sometimes place vegetable parchment, paper, linen, cotton or
other suitable substance containing cellulose between the indiarubber and the
said other material to protect the latter from the injurious effects of the sulphur
or cther corrosive material used in vulcanizing the indiarubber. Sometimes I use
textile fabrics starched or treated with a solution of Iceland or Irish moss or
carrigeen which assists in preventing puncture.
In tyres having indiarubber treads I sometimes solution fish skin, or other thin
skin tanned, tawed or otherwise dressed or preserved, to the outer tread, thereby
protecting the indiarubber from wear.
I prevent inflatable or pneumatic tyres from leaving the flat or other rims of
wheels in the following manner:-In aldition to the usual method of fastening
the tyres, whether by cement, wires, or otherwise, I wind tapes of any tough
material such as fish skin, particularly that of the pointed-nosed cel, transversely
and obliquely round both tyre and rim; sometimes forming channels in both
rim and tyre, or in either of them to receive the tapes which preferably
cement to both rim and tyre. Sometimes wind similar tapes over the first
in the opposite direction. These tapes not only prevent the tyre, or the cover
thereof, leaving the rim, but also so securely fasten the rim and tyre together
as to prevent creeping, and to distribute the strain occasioned by the tyre
biting the ground I sometimes cement over the aforesaid tapes, and especially
at the tread part of the tyre, bands of rough fish-skin which not only prevent
wear and tear of such tapes but help to keep them in place.
Dated this 8th day of August 1894.
A. PULBROOK,
Per W. H. Beck,
115 Cannon Street, London, Agent.

page_text: Improvements in and connected with Inflatable Tyres for the Wheels
of Cycles and other Carriages.
I, ANTHONY PULBROOK, 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 :—
This invention relates to the inflatable or pneumatic wheel-tyres of bicycles,
tricycles, and other carriages.
I make such a tyre of an outer tube of thin non-stretchable flexible material
containing inner tubes of elastic stretchable material, or of nou-stretchable material,
er some of the tubes of elastic stretchable material, and some of non-stretchable
material, air spaces being left between each two adjacent tubes. Each inner tube
is of smaller diameter than the next outer tube; and to keep each inner tube apart
from the next outer tube, and to preserve the air spaces between the tubes I surround
the inner tubes at intervals with distance pieces. These distance pieces may be
made of indiarubber or similar elastic material, but I prefer to make them of hollow
rings of indiarubber or other flexible impervious material containing elastic fluid
such as air or gas for example.
An air or gas supply valve sometimes opens into the innermost of the aforesaid
tubes, and when air or gas is forced into such innermost tube, in cases where the
inner tubes are made of elastic stretchable material, the latter expands and
compresses the air or gas confined in the space between it and the next outer tube
which latter expands in like manner, and compresses the air or gas confined in the
space between it and the next outer tube, and so on until the external tube is
reached and this being practically unstretchable prevents the expansion of the
inner tubes and compressed air or gas beyond certain limits.
I seek to form the tyre as much as possible of air, or other like compressible
fluid, 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 layers of compressed air between layers of a tough flexible but thin material
will, bulk for bulk, be lighter and more resilient.
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, when made with elastic or
stretchable inner tubes and before inflation,
Figure 2 a section of the same tyre after inflation,
Figure 3 a section of the same tyre partially perforated by a nail, and Figure 4
a longitudinal section.
I construct the air tube or tyre of two or more tubes A. B. C. of indiarubber, or
other elastic or stretchable air-tight material, 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 and more elastic 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. For instance I may make the inner tube of india-
rubber and the outer tubes of stretchable indiarubber, or balata compound, or of

page_text: stretchable leather, such as glove kid, made air-tight by treating it with a solution
of indiarubber or balata or other known elastic gum, or a mixture of the two, or
with any known air-tight flexible and elastic varnish, or I may use a compound tube
consisting of an outer covering of the grain part of skived or thin leather, made air-
tight as above mentioned, and having solutioned, or otherwise connected to it
(especially when the leather happens to be thinner or weaker at some parts than at
others) a fabric cut on the cross to allow of expansion when blown up, so that when
not blown up the contraction of the textile fabric, cut on the cross, to its normal
state will act on the outside leather covering and cause that to contract also by
reason of the two being connected together.
I also sometimes make more or less stretchable airtight tubes of fibrous materials
such as thin leather, silk and so forth, in the following manner :-I first make a tube
of thin indiarubber and stretch it equally in all directions. This may be effected by
filling it with compressed air or other fluid. Whilst in this condition I cement,
solution, or otherwise fix ou it an outer covering of the thin fibrous material such
as thin split or skived leather, or silk or other textile fabric. 1 allow the tube to
resume its normal condition, when the contraction of the indiarubber contracts the
fibrous covering as well, and thus an exceedingly strong elastic tube is made.
Sometimes I treat the leather with indiarubber or balata or a mixture of the two as
herein described. Sometimes instead of making a tube of indiarubber in the first
instance stretch a sheet of indiarubber in all directions and whilst in that condition
cement or solution the aforesaid material to it and make the whole into the tube
form afterwards.
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. 1 sometimes provide transverse ridges or distance pieces D (see
Figure 4) between the several laminations to assist in maintaining the air space
between them. I preferably make these distance pieces of hollow indiarubber or
other thin flexible airtight material, as shown at the right hand side of Figure 4,
and also in Figure 5, such hollow distance pieces being airtight, and containing air,
or other like finid, at or about atmospheric pressure.
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 indiarubber, being supported
by the surrounding laminations, pressed equally in all directions by the compressed
air between them, and being restrained by the outer cover, 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. The resilience of the com-
pressed air is more rapid in its action, and destroys vibration more, when confined
between layers of thin material, as before described, than when the same substance
and thickness of material is combined in one piece and acted on by the same
quantity and pressure of the air.
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 succeeding 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 from the outside is a great preservative
against puncture, because a substance can only be punctured when it offers a

page_text: Bufficient amount of resistance to prevent the puncturing object pushing the substance
before it instead of penetrating it. Moreover thin indiarubber, when not in a state
of tension, gives readily to a blow and stretches without being punctured as shown
by pushing the point of a pin against a sheet of very thin rubber not in a state of
tension.
It is customary to make tyres of indiarubber at their tread parts immediately
next the ground, and, to prevent wear and tear, to make that part thicker then the
part next the rim. The thinner the tread part of a tyre is, and the nearer the air
or gas is brought to the ground, the more resilient the tyre is, and consequently
the longer it will wear. therefore make the outside tread part of the tyre of thin
tough material such as fish skin, seal skin, horse hide, wamba skin, the grain part of
leather, or any tanned or tawed skin of any vertebrate animal, capable of being
rendered air and water proof by treating it with boiled oil, indiarubber, gutta percha
or balata solution, or with any known suitable flexible varnish or compound, and
inside that place thin iudiarubber with a confined air space between it and the
outside material so that when an expanding air tube is covered by this outside
covering the air in the confined air space is compressed by the expansion of the
said air tube within the covering.
A tyre formed as above described makes a very fast, resilient and light tyre
especially suited for a racing track.
A tyre, formed solely of indiarubber or other like elastic material, would expand
to a great size and would 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, or indiarubber combined with some non-
stretchable fibrous material as is usually done at present, but this thick cover,
whilst it allows for wear and tear of a material having a porous structure like
indiarubber, and protects the tube from cuts, 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. To make the material, of which the tubes are formed, air-
tight, or the outer cover watertight, it is customary to use indiarubber, but unless
vulcanised, that material hardens and cracks. Vulcanising has been found to
injure and destroy the material used to prevent expansion. Instead of using india-
rubber I use balata, the sap of Mimusops bulata, or Mimusops globosu, or other like
gum which may be exposed to several degrees of frost without losing its flexible
character or becoming brittle and which does not harden or crack so readily as
indiarubber though not vulcanized. I dissolve the balata in bisulphide of carbon,
chloroform, warm mineral naphtha, or any other suitable known solvent, or I some-
times mix such a solution with a similar solution of indiarubber, and I then either
steep the material to be made air or watertight in the solution or mixture of
solutions which I prefer to make somewhat thin in order that it may thoroughly
penetrate every part, or I paint or otherwise saturate the material with the same.
prefer to use the solution warm as I find it acts better than when cold. I then
dry it, preferably in a warm dry atmosphere, and when dry, give it one or more
other coats. I prefer to rub the material with glass paper in the first instance to
assist penetration. I shape skins to the size of the tyre by moistening them either

page_text: in water, or water in which a little borax is dissolved, or in benzine, and whilst wet
stretching the skin on a form the size of the tyre and when dry treating it with the
waterproof solution.
In Figures 1, 2, 3 and 4 of the drawings, E represents an outer airtight casing
composed of fish skins as above mentioned, or other suitable thin and tough ant
practically non-stretching material, whereby the expanding action of the compresse
air is confined to the inner tubes or laminations and has little or no expanding effect
upon the said outer casing E.
In a tyre formed of internal tubes of indiarubber as above described, after a
puncturing substance has penetrated the outer skin, there would be no puncture-
resisting material other than the indiarubber inner tubes or laminations to withstand
its puncturing action. Indiarubber, when in thin sheets, in a state of tension, offers
but little resistance to puncture by a sharp point. I therefore interpose in the air
spaces between the indiarubber tubes or laminations, especially at the tread parts
thereof, bands of more or less non-puncturable material, or material difficult to
puncture, 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, hemp, and such like (such fibrous materials
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. Sometimes I saturate the fibrous material, above mentioned, with a
solution of carrageen or Irish moss. Such bands are shown at F. G. and H in
Figures 1, 2, 3 and 4, and are continued longitudinally all round the tyre, the
transverse bands or distance pieces D, when such are employed, and solutionel
down at their ends, tending to keep such bands of more or less non-puncturable
material in place. Sometimes only carry the protecting material up to, and not
under, each distance piece to give a greater latitude for movement, as shown in
Figure 5. Being entirely free and loose, except where they are pressed to the
tubes by the transverse bands or distance pieces, and the tubes being kept apart by
the compressed air between them (such compressed air pressing equally in all
directions) the bands of more or less non-puncturable or protecting material are not
jamined, but 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 or other 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, and pressed by the elastic fluid equally on all sides,
affords insufficient resistance to enable the puncturing substance to perforate it, and
gives or yields until it reaches the indiarubber tube immediately over it. This
latter, being pushed as it were by a considerable surface of the protecting material,
stretches and 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, the said
next indiarubber tube expands (as the air escapes through the puncture) 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 use 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 also place material more or less difficult to puncture, such as fisb skin, leather,
bladder, gold-beater's skin, and so forth, in air spaces between laminations of india-
rubber, or balata, or of indiarubber or balata compound, or a mixture of the two, at
the tread of the inflatable tube in the following manner :-
I take the strip of material A² (see Figures 6 and 7) intended to form the
outermost tube, before it is folded over into the tubular form, and I place on it, at
the part where the tread of the tyre is to be, one or more strips or bands H' of the
above mentioned more or less non-puncturable material. I then lay a somewhat
broader strip or band 1¹ of indiarubber or balata, or of a compound of those

page_text: substances, over the said strip or band H2, and cement the edges to the tube strip A².
I then place over this if necessary one or more other strips or bands H₁ of
the more or less non-puncturable material, and cover it or them with another strip
or band of preferably thin indiarubber or balata or of indiarubber or balata
compound, or a mixture of the two substances, and cement the edges of this strip to
the tube strip A, and similarly with the strips or bands H and I", and so on, to
any required number of thicknesses. Strips or bauds H* of the more or less non-
puncturable material may then be added, and over these, strips or bands A¹ of
thin indiarubber with their edges cemented to the strip or band of indiarubber I*.
The strips or bands so prepared, as shown in Figure 6, are then made up into the
tubular form as shown in Figure 7, the longitudinal edges of A' and A² being
properly cemented together to form separate airtight tubes and compartments.
These tubes and compartments are theu bent into the hoop form, and the ends of
each individual strip or band of indiarubber or balata, or compounds of those
substances, are cemented together so that each strip or band of more or less non-
puncturable material is contained or enclosed in a separate airtight casing.
By these means a practically non-puncturable tyre is obtained which is as
resilient as an ordinary inflatable tyre not provided with any such protection.
Figure 8 shows the application of the same principle of construction, namely the
enclosing of more or less non-puncturable material in separate airtight chambers,
to the outer covering of the tyre, the inflatable tube proper A, which may be a
single tube, or of laminated or other suitable construction, being placed in the
hollow rim of the wheel and held therein by the cover B in any known or suitable
way. H2 H' represent the more or less non-puncturable material and I, I, the
strips of thin indiarubber, balata, or compound of those substances, cemented over
them to the cover B.
When air or other elastic fluid under pressure is introduced into the inflatable
tube A in Figure 8 or into the inflatable tube formed by the parts A and I* in
Figure 7, the said tube tends to expand, and this compresses the air in the airtight
space between the said tube and the next outer lamination; this latter in turn
compresses the air in the airtight space between itself and the next outer lamination
and so on for as many laminations as there may be.
I sometimes so connect together transversely at intervals the airtight casings.
surrounding the inner tube that the airtight spaces between such casings are
divided into sections laterally, so that in case of the puncture of an outer section,
the air may still remain confined in the other sections, so as to retain the original
degree of resiliency of the tyre in those unpunctured sections, notwithstanding the
puncturing of the outer tubes of the other section or sections. This arrangement
is shown in Figure 9 in which A is the inner airtight tube, A' an outer airtight
tube or lamination cemented at intervals at A* transversely or circumferentially
to the tube A, and A2 A3 are other similar outer airtight tubes or laminations,
cemented at intervals transversely or circumferentially in a similar way to the
casing A and to one another as shown, so as to form a number of separate airtight
sections or chambers between each pair of laminations; and each of these airtight
sections or chambers contains a piece of fish skin or more or less non-puncturable
material II, H³, He placed at the tread or other part of the tyre which is liable to
be punctured.
I sometimes make the laminated inflatable tube with one or more of such tubes
preferably made of more or less non-puncturable protecting material, each tube
being made smaller in diameter than the one surrounding it, so as to leave an air
space between any two adjacent tubes, and to assist in preserving these air spaces
1 sometimes place distance pieces between the tubes as before described. The
tubes, made of protecting material, may be stretchable or not as preferred; but
1 prefer to make the outermost tube of non-stretchable material to prevent undue
expansion. In the case of a laminated tube having one or more inner airtight
tubes made of more or less non-puncturable and more or less non-stretchable
material, the compressed air forced into the inner tube in the usual manner would

page_text: have no effect in compressing the air between the said inner tube and the outer
tube or tubes of unstretchable material, and the latter tube or tubes would be loose,
and the tyre would have little or no resilience; 1 therefore provide in such case a
separate valve, of the usual description, passing through the rim of the wheel in
the usual manner to open into each tube of non-stretchable airtight material so
that compressed air can be forced between any two adjacent laminations. This
arrangement is shown diagrammatically in Figure 10 in which A is a tube which
may be made of non-elastic material such as vellum, parchment, vegetable
parchment, or bladder, or raw or tanned hide or skin, fish-skin, and such like, made
airtight by treatinent with indiarubber or balata solution or mixtures of such
solutions, or boiled oil, or auy known suitably flexible varnish or compound. His
protecting material not necessarily airtight, or this may be dispensed with if
preferred. A is a tube made of similar non-stretchable non-puncturable airtight
material. A is an airtight tube which may be made of non-stretchable,
non-puncturable material similar to the tubes A'A' or of elastic material such as
indiarubber for example; and E is an outer covering of non-stretchable material.
K is a charging valve opening into the inner tube A, K' a charging valve
opening into the space between the tubes A and A, and K' a charging
valve opening into the space between A. and A. It will be understood
that the separate valves K K and K are respectively placed at different points
round the rim and that airtight joints are made where the valves pass through the
several tubes in any suitable inauuer such as by the pressure of the flange at
the lower end of the valve tube against the inner surface of the air tube in the
usual way.
I do not allow any of the inner tubes to remain in a state of collapse, only to be
brought into use on the deflation of the tyre as is at present customary in some
arrangements, but on the contrary, I fully charge them all with air under pressure,
with the two-fold object of making the tyre as resilient as possible, and of
rendering the pressure both inside and outside of the inner tubes nearly alike so
that no inner tube will be in a state of tension. Sometimes I effect the compression
of air or gas introduced into a tyre in the following manner :-I first make a tube
A, see Figure 11, of indiarubber compound, balata compound, thin oiled silk, or
other oiled or varnished textile fabric or other material impervious to air or gas.
I fill this with air for example at or above atmospheric pressure, and I close
hermetically the aperture through which the air has been forced in so as to retain
the air in the said tube. At intervals round the tube I place distance pieces (such
as those before described with reference to Figure 4) which have preferably a
smaller internal diameter than the tube A, when the latter is inflated. I then
sometimes enclose the aforesaid tube A. with its distance pieces, within another
tube A' made of similar material, and similarly fill the space between the two tubes
with air at or above atmospheric pressure, and 1 place over this second tube other
distance pieces similar to those round the first tube. Over this second tube A'1
sometimes place a third A² which I similarly fill with air and place other distance
pieces outside it, and so on to any required number of tubes; then outside all 1
place a tube or cover E made of non-stretchable material which is impervious t▸
air or gas. This outer tube or cover E is provided with an air inlet or charging
valve S of the usual character.
On forcing air under pressure through the said valve S into the outside tube or
cover E, that pressure is communicated to the air in all the interior tubes, and
these tubes being thin and flexible give way before the pressure, are more or less
collapsed thereby as shown by dotted lines in the figure, and are kept away clear
of the range of puncturing materials. In the event of the outside tube or cover
containing air under pressure being punctured, the air in the internal tube or tubes
expands, and restores the said tube or tubes to its or their normal condition, and
the tyre consequently still remains inflated to a certain extent and can be used till
a convenient point is reached for repairing the puncture in the outer tube or cover.
By the compression of the air inwards against the walls of the inner tubes the said
B

page_text: walls, being subjected to the same pressure of air on both sides, offer little or no
resistance, and, not being in a state of tension, are less liable to puncture than tubes
subjected to an unbalanced internal pressure.
According to a modification of the last described arrangement I provide each of
the internal tubes A A' A' with a valve opening inwards (as shown for example
at T in Figure 12) so that when air under pressure is forced into the outer tube
or cover E through the charging valve S it finds its way through the said valves T
into the interior of the said internal tubes, and in the event of the outer tube or
cover, or even one or more of the internal tubes being punctured the said valves
prevent the escape of the compressed air from the internal tubes, or such of them
as may not have been punctured; and they consequently remain inflated tubes
available for use until an opportunity is afforded to repair the punctures in those
tubes which have been deflated.
Sometimes I attach, by cement or otherwise, (see Figure 13) that portion of an
inner tube A that comes next to the rim U to some non-stretchable material, or to
part of the cover E which at this point I cement or otherwise fasten to the
rim U; and I leave the remainder of the tube loose inside the outer
airtight casing. I do not allow this tube to remain in a state of collapse,
but fill it with compressible air or gas, so that on air or gas being
introduced under pressure into the outer covering, and between it and the
part of the inuer tube hanging loose, the air or gas in the said inner tube is
compressed, and the part of the tube not connected to the non-stretchable material
is forced towards the rim, and being a loose piece in a state of equilibrium, that is
to say subjected to almost equal pressure on both sides, it is less liable to puncture
and yields to a blow. I do not use a separate valve to the inner tube in this case
but fill the latter with air somewhat above atmospheric pressure before enclosing it
in the outer casing as before described.
When I use india-rubber I sometimes place the more or less non-puncturable
material between the surfaces of vegetable parchment, paper, linen, cotton, or
other suitable substance containing cellulose to protect the material from the
injurious effects of the sulphur or other corrosive material used in vulcanizing the
india rubber, and to give smooth surfaces for the skin or other material to
slide upon.
I prevent inflatable or pneumatic tyres leaving the flat or other rims of wheels
in the following manner :-
In addition to the usual method of fastening the tyres, whether by cement,
wires, or otherwise, wind tapes of any tough material such as fish skin,
particularly that of the pointed-nosed eel, or of the tope or blue shark, or other
fish of that tribe having small spines, transversely and obliquely round both tyre
and rim as shown in Figure 14, sometimes forming channels in both rim and tyre,
or in either of them, to receive the tapes which I preferably cement to both rim
and tyre. Sometimes I wind similar tapes over the first in the opposite direction,
and sometimes I use two or more sets of tapes V VI passing over and under each
other as illustrated in the said Figure 14. I preferably treat the tapes with balata
solution to render them waterproof. These tapes not only prevent the tyre, or
the cover thereof, leaving the rim, but also so securely fasten the rim and tyre
together as to prevent creeping and enable the full resilience of a pneumatic tyre
to be obtained by enabling a very flat rim to be used, and they prevent the
bursting of the tube when rough fish skins are used on the tread by distributing
the strain caused by the rough fish skin biting the ground, the strain being throwu
on the back of the rim and not on the tube. I prevent the fraying and wear and
tear of the tapes where they run on the ground, and keep them in place, by
cementing or otherwise fastening longitudinal strips W of rough fish skin at the
tread part of the tyre, outside the aforesaid tapes.
I am aware that it is has been proposed to employ concentric tubes made of
elastic or compressible material fitting closely to and lying or nested within each
other but it is an essential and distinctive feature of my invention that the

page_text: laminations or tubes should not fit closely one in the other, but that air or gas
spaces should be left between any two adjacent tubes, the air or gas thus confined
between the tubes making the tyre resilient. A tyre made up of laminations not
separated from each other by air spaces, but fitting closely together becomes, by
reason of the pressure of the air in the inner tube, one compact body which, as
far as resiliency is concerned, is little if at all different from a solid tyre
composed of material having the same thickness as the aggregate thickness of the
laminations.
I am also aware that it has been proposed to employ in a tyre multiple endless
tubular linings loose one within the other, and adapted to slightly vary or alter
their relative positions sufficiently to cover a puncture, in the event of such
occurring, the inflation of the tube so formed with linings taking place through a
single air filling tube which communicates with the internal or central lining; but
it is an essential and distinctive feature of my invention, when the inflation takes
place in that manner, that the laminations should be of india rubber or other elastic
material which will stretch or expand under the pressure of the contained air or
gas, and regain their normal size when that pressure is removed, so that each tube
being of a smaller diameter than that surrounding it, air spaces always exist
between any two adjacent tubes. These air spaces would be fatal to the purpose
of covering a puncture, as in such a case there would be no loose material to
come in contact with and cover the punctured part and prevent the escape of air
or gas.
Having now particularly described and ascertained the nature of the said inven-
tion, 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, with air
spaces between them, the pressure of the compressed air introduced into the
innermost tube being trausnitted to the air in the said air spaces, substantially as
described with reference to Figures 1, 2 and 3 of the drawings, and for the purpose
specified.
Second. An inflatable wheel tyre composed of tubes of indiarubber or other
suitable elastic material placed inside one another, forming laminations with air
spaces between them, having flexible material which is more or less non-puncturable,
or more or less difficult to puncture, interposed in the air spaces, or in some of them,
between the said laminations, substantially as described with reference to Figures 1, 2,
and 3 of the drawings, and for the purpose specified.
Third. In inflatable wheel tyres the use of more or less non-puncturable material,
or material difficult to puncture, enclosed in separate airtight chambers composed of
air spaces between indiarubber or other clastic and airtight material cemented to
the inflatable tube, or to the outer covering thereof, substantially as described with
reference to Figures 6, 7, and 8 of the drawings.
Fourth. A pneumatic or inflatable wheel tyre constructed with separate
airtight chambers composed of stretchable airtight material, substantially as
described with reference to Figures 1, 2, 3, 4, 5, 6, 7, and 9 of the drawings.
Fifth. A cover for a pneumatic or inflatable wheel tyre constructed with separate
airtight chambers composed of stretchable airtight material, substantially as
described with reference to Figure 8 of the drawings.
Sixth. An inflatable wheel tyre composed of tubes of impervious material
charged with air at or above atmospheric pressure and placed inside one another so
as to form laminations with airtight spaces between them, the pressure of the
compressed air introduced into the outermost tube being transmitted to the air
in the inner tubes, so as to partially collapse the same, substantially as described
with reference to Figure 11 of the drawings, and for the purposes specified.
Seventh. An inflatable wheel tyre composed of tubes of impervious material
placed inside one another so as to form laminations with airtight spaces between

page_text: them, the inner tubes being provided with valves opening inwards, and the outer
tube with a supply valve opening into the air space between the said outer and
next inner tube, substantially as described with reference to Figure 12 of the
drawings, and for the purposes specified..
Eighth. In an inflatable wheel tyre composed of tubes of impervious non-
stretchable material placed inside one another, as shown in Figure 11, the use of a
separate charging valve opening into each tube, substantially as described with
reference to Figure 10 of the drawings, and for the purpose specified.
Ninth. In an inflatable wheel tyre the use of leather treated with balata, as a
material for the inflatable tubes or for the coverings therefor, substantially as
described.
Tenth. In an inflatable laminated tyre the use of hollow distance pieces of
flexible material to keep the laminations apart, and to preserve air spaces between
the same, substantially as described with reference to Figures 4 and 5 of the
drawings.
Eleventh. Protecting the pneumatic or inflatable tube of a tyre from puncture
by subjecting it, or other protecting material outside such tube, to equal or
nearly equal pressure of a compressible fluid on both sides, substantially as
described.
Dated this 8th day of May 1895.
A. PULBROOK,
Per W. H. Beck,
115 Cannon Street, London, E.C., Agent.