Improvements in and relating to Pneumatic Tyres.
Year: 1896

page_text: Date of Application, 1st Aug., 1896
Complete Specification Left, 1st June, 1897-Accepted 3rd July, 1897
PROVISIONAL SPECIFICATION.
Improvements in and relating to Pneumatic Tyres.
I, THOMAS DUNN, of 83 Tierney Road, Brixton Hill, in the County of London,
Member of the Stock Exchange, do hereby declare the nature of this invention
to be as follows:-
Great importance attaches to constructing pneumatic tyres for cycles and
particularly for other vehicles, in such a manner that in the event of deflation
they may still be used, at least temporarily, without discomfort to the user or
danger of serious injury to the tyre. Various devices for this purpose have
hitherto been tried, but all those known to me, excepting those which merely
provide that the surface beneath the air tube shall be flat so that the tyre is free
from liability to be cut, if used deflated, by the projecting edges of a concavity
beneath it, add so seriously to the weight of the tyres that they cease to be
really pneumatic tyres and are rather inflated cushions. Now this invention is
designed inter alia, to render pneumatic tyres, whether for cycles or other
vehicles, quite serviceable for use when deflated, at least temporarily, without
materially adding to their weight or in any way detracting from their ad-
vantages when used inflated but rather increasing their resiliency.
To this end the tread of the tyre is so constructed or adapted that when
the tyre is deflated, it will contract so tightly upon the rim or wheel that instead
of the tyre flapping and rolling about as a deflated pneumatic tyre ordinarily
does, the tyre will be so compact upon the wheel that it will, for the time
being, furnish a perfectly efficient solid elastic tyre.
For this purpose there is combined with the tread portion of the tyre, a
contractile band that is practically inextensible in length beyond the normal
working length and which may conveniently be composed of a number of short
links of suitable material, for example metal, held together lengthways by elastic
or yielding material that tends to contract the band in diameter and prevent
it being increased in diameter beyond a given amount.
According to one construction, such a band comprises a series of flattened wire
spirals or coils which are formed into a band or chain by being inserted edge
ways into one another until the spirals of each pair overlap one another to the
extent of say about half their length. Cushions consisting of strips or blocks of
elastic material such for example as india rubber, preferably covered with material
such as canvas, are then inserted within and between the ends of each pair of
links, rods or strips of some hard substance such as metal, wood, vulcanized fibre
or the like being preferably placed before and behind the elastic cushions to
prevent the wire cutting them. On tension being then put upon the chain-like
band thus formed, it will be found that the effect will be to compress the elastic
cushions between and within the links so that a band of great strength, and
when under tension, having a powerful contractile action, will be obtained.
The construction described gives to the band a great range of elasticity but
it is unsuited to bear the severe strains liable to be put on it in tyres of
large circumference unless the elastic cushions contain a greater body of india
rubber than it is generally convenient they should have. I will hereinafter
describe a modified form of this construction which though having less range of

page_text: elasticity, is designed to bear much higher strains in proportion to the size of
the india rubber cushions. The size of the spiral wire links and the relative size
of the elastic strips or blocks may be varied so as to give the band a greater or
less degree of elasticity as may be desired. The wires of each spiral may
advantageously cross one another at one or more points in their length and as
seen in edge view of the band so that the band may bend freely longitudinally
at the crossing point or points. This crossing of the wires of each spiral may
be effected at one point in the winding of each spiral, or at two or more points,
by interlacing the wires with one or more transverse pins.
A contractile band such as described under whatever degree of tension is found
to be most desirable, may be enclosed in a sheath of suitable textile or flexible
material, for example canvas, and be embedded in the thickened portion or tread
of the tyre or be firmly attached to the inner surface thereof all around the same.
It then contracts the tyre circumferentially so that it requires to be stretched
to get it on to the wheel and holds the tyre when deflated in close contact with
the wheel all round as described, but will expand to a sufficient, but limited
extent when the tyre is inflated.
A tread constructed as described may advantageously be used in tyres of the
kind adapted to be attached to a wheel by a self gripping action, as for example
by a self-gripping band subject to the pressure of the air in the air tube of the
tyre, as described in the specifications of Letters Patent No. 23423 of 1892 and
6357 of 1894, or by modified constructions described in the specification of
Letters Patent No. 14953 of 1894 and in the specifications of applications for
Letters Patent Nos. 14700 and 15120 both of 1895, as such a construction of
tread gives to tyres attached by means of a self gripping band, a greater efficiency
in the self gripping action of such tyres, and a greatly increased capacity of
the tyres to adapt themselves to variations in the circumference of the wheels
to which they are to be applied-which is particularly important in the case
of ordinary road vehicle tyres owing to the great variety in the sizes of the
wheels of such vehicles.
In some cases a contractile band such as described, under whatever degree of
tension may be found to be desirable, may advantageously be placed not only
under or within the tread of a tyre, but also on the top of and around a self-
gripping band of the kind hereinbefore referred to placed in the base of a tyre
in order to facilitate the action of the said self gripping band, or to render it
independent of the action of the air pressure in the tyre in causing it to grip
upon the wheel.
When thus placed over a self gripping band in a tyre of
the kind referred to, the contractile band will form a ridge which should be
arranged to fit the channel formed in the under side of the specially constructed
treads described in some of the former specifications hereinbefore referred to so
as to keep the tread in the centre line or plane of the wheel whilst the tyre is
being used in the deflated condition and so to still further prevent the flapping
and rolling ordinarily exhibited when a pneumatic tyre is used deflated.
A contractile band such as hereinbefore referred to may be used in conjunction
with tyres having thick transversely inflexible trends such as described in the
Specifications of Letters Patents Nos. 14173 and 15952 of 1891. In this case the
contractile chain-like hand is used in the place of the band of plates or of
corrugated steel.
This invention also has reference to the constructions of pneumatic tyres with
treads that are practically inextensible in length beyond the, normal, though
capable of readily undergoing slight contraction under compressive strain and
of afterwards readily recovering their original length and which can advantageously
be used in conjunction with attaching devices of the kind referred to in the
said former specifications in which a self gripping action takes place. For this
purpose there is provided in connection with the tread of a tyre, an inextensible
but contractible band which, according to one construction, is similar to that
hereinbefore described except that the strips or blocks of elastic material are

page_text: dispensed with and the flattened wire spirals are simply connected together by
transverse pins, the arrangement, which somewhat resembles a chain or link belt,
being such that the pins will limit the extent to which the links can be drawn
apart, but will permit such links to slide towards each other to enable the band
to readily undergo slight contraction in length when required. According to
another construction, the inextensible but contractible band is composed of three
or more circumferential strips or a series of wires of material, for example steel,
arranged side by side, and a series of plates, bars or strips (hereinafter called
plates) of material for example, vulcanite, wood and the like that are arranged
transversely of the tyre and are interlaced with the said circumferential strips
or wires which consequently prevent the appearance of a number of loops and
nodes, the arrangement being such that whilst the plates will serve to prevent
the compound band from extending in length under tensil strain, they will
permit it to readily undergo slight contraction in length under compressive
strain, and will enable it to readily recover its original length. The transverse
plates in this construction though they may be rendered rigid transversely may
be made of blocks or cushions of elastic material such as india rubber. This
will give the band a slight degree of elasticity in its length and a corresponding
slight but very powerful contractile action. I find the construction superior to
the one first herein described for withstanding heavy strains.
The circumferential strips or wires in each of these cases may originally be
of plain circular form, in which case they will assume a wavy or corrugated form
when interlaced with the transverse plates. When however it is desired to
provide for greater contractibility, the strips may have a wavy, corrugated or
crenelated form imparted to them initially, the degree of ready contractibility
depending upon the number or pitch of the corrugations or crenelations.
The spaces at the inner and outer sides of the compound band are or
may be fitted with plates of plano-convex form in cross section, preferably
rigid transversely, so that the compound band is approximately of uniform
thickness throughout its length. The ends of the transverse plates should be
arranged to project slightly beyond the outer edges of the circumferential strips
or wires and be bevelled to correspond with the curvature of the sides of the
tyre at the points where they terminate. Each of the inextensible but con-
tractible or contractile bands herein before described may be variously arranged.
Thus such a band may be simply placed between the air tube and the thickened
portion or tread of the tyre or tyre cover, a strip of canvas or equivalent material
being preferably placed between it and the air tube to prevent damage to the
latter and to secure the band in its place. Or the said compound band may
be enclosed in a sheath of suitable textile or flexible material, for example
canvas, and arranged either as just described, or be embedded in the thickened
portion or tread of the tyre which may be of india-rubber or an elastic substitute
therefor.
I, THOMAS DUNN, of 83 Tierney Road, Brixton Hill, in the County, of London,
Member of the Stock Exchange, do hereby declare the nature of this invention and

page_text: in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
Great importance attaches to constructing pneumatic tyres for cycles and
particularly for other road vehicles, in such a manner that in the event of deflation
they may still be used, at least temporarily, without discomfort to the users or danger
of serious injury to the tyres. Various devices for this purpose have hitherto been
tried, but all those known to me, excepting those which merely provide that the
surface beneath the air tube shall be flat without projecting parts so that the tyre is
free from liability to be cut, if used deflated, by the edges of a concavity beneath it,
add so seriously to the weight of the tyres that they cease to be really pneumatic
tyres and are rather inflated cushions.
Now this invention is designed inter alia, to render pneumatic tyres, whether for
cycles or other vehicles, quite serviceable for use when deflated, at least temporarily,
without materially adding to their weight or in any way detracting from their
efficiency when used inflated but rather increasing their resiliency. To this end the
tread of the tyre is so constructed that when the tyre is deflated, it will contract
tightly upon the rim or wheel so that instead of the tyre flapping and rolling from
side to side as a deflated pneumatic tyre ordinarily does, it will be compact upon the
wheel and will, for the time being constitute a perfectly efficient solid elastic tyre.
For this purpose there is combined with the tread portion of the tyre, a contractile
band which may conveniently be composed of a number of short links of suitable
material, for example inetal, held together lengthways by strips or blocks of elastic or
yielding material which are compressed by stretching the band so that the band
being normally stretched to the needful degree when introduced into the tyre during
the manufacture thereof, it contracts the tread of the tyre in diameter and on
deflation of the tyre when on a wheel makes the tread grip firmly on the wheel.
In the accompanying drawings Figs. 1 and 2 show respectively in cross section and
longitudinal section, a portion of a wheel with a pneumatic tyre the tread of which is
constructed with a contractile band such as referred to. Figs. 3 and 4 show respec-
tively in plan and edge view, a portion of the contractile band detached from the tyre.
In this construction of pneumatic tyre, the contractile band is formed of a series
of flattened wire spirals or coils 1, constituting links, which are joined into a band or
chain by being inserted endways into one another until the spirals of each pair
overlap one another to any suitable extent up to half their length, and are then
connected by cushions 2 consisting of transverse strips or blocks of elastic material,
for example india rubber, preferably covered with material such as canvas which are
inserted within and between the ends of each pair of links as shown, rods or strips 3
of some hard substance such as metal, wood, vulcanized fibre or the like, being
preferably placed before and behind the elastic cushions to prevent the wire of which
the spirals or coils 1 are made, cutting them. On tension being put upon the chain-
like band thus formed, it will be found that the effect will be to compress the elastic
cushions 2 between and within the links 1 so that a band of great strength, and
when under tension, having a powerful contractile action of greater or less range
according to its construction will be obtained."
The construction described gives to the band a comparatively great range of
elasticity but it is unsuited to bear the severe strains put on it in tyres of large
circumference unless the elastic cushions 2 contain a greater body of india rubber
than it is generally convenient they should have. I will hereinafter describe with
reference to Figs. 9 and 10, a modified form of this construction, which, while having
a less but sufficient range of elasticity, will bear much higher strains in proportion to
the size of the india rubber cushions, and which is consequently well suited for tyres
of large diameter. The size of the spiral wire links 1 and the relative size of the
elastic strips or blocks 2 may be varied so as to give the band a greater or less degree
of elasticity as may be desired. The wires of each spiral may be made to cross one
another as seen in edge view of the band and as shown in Fig. 4, so that the band
may bend freely longitudinally at each crossing point 1".

page_text: A contractile band such as described, may conveniently be enclosed in a sheath 4
(Figs. 1 and 2) of suitable textile or flexible material for example canvas, and (under
whatever degree of tension is found to be most suitable) be embedded in the tread 5
of the tyre. The tread as shown, is made thick to receive the band and to provide
sufficient material to enable it to be used as a solid elastic tyre, and it is preferably
made transversely inflexible for the reasons stated in my prior specifications
Nos. 14173 and 15952 both of 1891. Or the band may be firmly attached to the inner
surface of the thickened portion or tread all around the same, as shown in Fig. 5,
where the band is shown arranged between the tread and the inner of the two layers
of fabric used in the construction of the tyre cover. In each case the band contracts
the tyre circumferentially so that it requires to be stretched to get it on to the wheel.
and holds the tread of the tyre, when deflated, in close contact with the wheel all
round as described, but will readily expand to the necessary extent when the tyre is
inflated.
I have obtained satisfactory results with bands made up of wire spirals 1 of from an
inch to one and a half inches in length and from an eighth to a quarter of an inch in
thickness. I prefer to make up the spirals of steel wire of small gauge so that the
band will be as flexible as possible longitudinally, and in a band an inch and a half
broad there may be about twenty convolutions in each spiral. The degree of tension
under which the bands are introduced into the tyres, when making up the same, is
such that it requires a force, such as can be conveniently exerted by an ordinarily
strong man, to stretch the tyre on to the wheel to which it is to be applied.
A trend constructed as described may advantageously be used in tyres of the kind
adapted to be attached to a wheel by a self gripping action, as for example by a self-
gripping band subject to the pressure of the air in the air tube of the tyre, as
described in the specifications of Letters Patent No. 23423 of 1892, No. 6357 of 1894
No. 14953 of 1894, and Nos. 14700 and 15120 both of 1895, as such a construction of
tread gives to tyres attached by means of a self gripping band, a greater efficiency in
the self gripping action of such tyres, and a greatly increased capacity of the tyres to
adapt themselves to variations in the circumference of the wheels to which they are
to be applied-which is particularly important in the case of ordinary road vehicle
tyres owing to the great variations in the sizes of the wheels of such vehicles.
In the example shown in Figs. 1 and 2, the tyre is secured upon a vehicle wheel 6
having a flat or approximately flat rim or iron tyre 7 by a self gripping band 8 capable
of sliding in a sheath 9 and acted upon by the air pressure in the inflated air tube 10
as above referred to so as to hold the extensible but laterally stiffened edges 11, 11
of the pneumatic tyre and two sets of angle pieces 11b 11° around the wheel rim, the
angle pieces consisting of plates or strips connected to the said edges 11 11 and the
free ends of which are adapted to engage with the sides or edges of the wheel
on opposite sides thereof, as described in the said former specification No. 14700 of
1895.
In some cases a contractile band such as hereinbefore described, under whatever
degree of tension may be found to be 'desirable, may advantageously be placed not
only under or within the tread of a tyre, but also on the top of and around a self
gripping band of the kind hereinbefore referred to placed in the base of a tyre in order
to facilitate the action of the said self-gripping band, or to render it independent of
the action of the air pressure in the tyre in causing it to grip upon the wheel. When
thus placed over a self-gripping band in a tyre of the kind referred to, the contractile
band should be made to form a ridge which should be arranged to fit the channel
formed in the under or inner side of the specially constructed treads described in
some of the former specifications hereinbefore referred to thereby more effectually to
keep the tread in the centre line or plane of the wheel whilst the tyre is being used
in the deflated condition and so to still further prevent the flapping and rolling from
side to side ordinarily exhibited when a pneumatic tyre is used deflated.
Fig. 6 is a cross section showing a tyre provided with a contractile band 1-2
similar to that in the tread thereof and enclosed in a sheath 4 arranged to act directly
upon and around the self gripping band 8 as and for the purpose above set forth, the

page_text: said contractile band being arranged (when the tyre is deflated) to fit the annular
channel 5* in the under or inner side of the tread portion of the tyre.
This invention also has reference to improved constructions of pneumatic tyres
with treads that are practically inextensible in length beyond the normal, though
capable of readily undergoing slight contraction under compressive strain and of
afterwards readily recovering their original length and which can advantageously be
used in conjunction with attaching devices of the kind referred to in the said former
specifications in which a self gripping action takes place. For this purpose there is
provided in connection with the tread of a tyre, an inextensible but contractible band
of improved construction.
Figs. 7 and 8 show respectively in cross section and longitudinal section, part of
the tread portion of a tyre with one construction of inextensible but contractible band
according to this invention. This band is similar to that shown in Figs. 1 to 4
inclusive except that the strips or blocks of elastic material are dispensed with and
the flattened wire spirals or links 1 are simply connected together by transverse
pins 2 of rigid material, for example steel, the arrangement, which somewhat resembles
a chain or link belt, being such that the said pins will limit the extent to which the
links can be drawn apart, but will permit such links to slide towards each other to
enable the band to readily undergo slight contraction in length when required.
Figs. 9 and 10 show in plan and edge view a band composed of link like wire spirals 1b
connected together by transverse pins 2 of rigid material like the band shown in
Figs. 7 and 8, but the spirals are made of approximately oval form as seen in side
view, and of spring wire and a transverse strip 2b of elastic material such as rubber
is or may be passed through the central portion of each link as shown, the arrange-
ment in either case being such that the band has a slight degree of longitudinal
elasticity due to the form of the links and the spring of the wire.
Figs. 11 and 12 are similar views to Figs. 7 and 8 showing another construction in
which the inextensible but contractible band is composed of three or more
circumferential strips 13 (or it may be a series of wires) of inextensible material, for
example steel, arranged side by side, and a series of plates, bars or strips 14 (herein-
àfter called plates) of hard material such for example as vulcanite, wood and the like,
arranged transversely of the tyre and interlaced with the said circumferential strips 13
(or wires) which consequently present the appearance of a number of loops and
nodes. As will be readily understood, the arrangement is such that whilst the plates 14
will serve to prevent the compound band from extending in length under tensile
strain, they will permit it to readily undergo slight contraction in length under
compressive strain, and will enable it to readily recover its original length. The
transverse plates 14 in this construction may be rigid in the transverse direction of
the tyre, or they may be made of blocks or cushions of elastic material such as india
rubber, which can be rendered rigid transversely by having plates of stiff material, as
for example steel, placed upon both sides of them. These transverse plates may be
slightly curved in section to add to their stiffness. This construction will give
the band a slight degree of elasticity in its length and a corresponding slight but
very powerful contractile action. I find this construction superior to that herein before
described with reference to Figs. 1 to 4, for withstanding heavy strains and for giving
the powerful contractile action desirable in the case of tyres of large circumference.
The circumferential strips 13 (or wires) in each of these cases may originally be of
plain circular form, in which case they will assume a wavy or corrugated form when
interlaced with the transverse plates 14. Or the strips may have a wavy, corrugated
or crenelated form imparted to them initially. The degree of elasticity (ready
contractibility) of the bands (in the case of elastic bands) depends upon the number,
i.e. pitch, of the corrugations or crenelations and the thickness of the elastic blocks.
The spaces at the inner and outer sides of the compound bands are or may be
fitted with plates 15 (Fig. 12) of plano-convex or pyramidal form in cross section and
preferably rigid in the transverse direction of the tyre so that the compound band is
approximately of uniform thickness throughout its length and rigid transversely.
The ends of the transverse strips or plates used in my bands should as shown in

page_text: the several examples be arranged to project slightly beyond the outer edges of the
spirals 1 or of the circumferential strips 13 (or wires) and be bevelled at their ends to
correspond with the curvature of the sides of the tyre at the points where they
terminate.
Each of the inextensible but contractible or contractile bands herein before
described with reference to Figs. 7 to 10 inclusive may be variously arranged. Thus
such a band may be attached to the inner side of the thickened portion or tread of
the tyre or tyre cover as shown in Figs. 7 and 8, a strip 16 of canvas or equivalent.
material being preferably placed between it and the air tube to prevent damage to
the latter and to further secure the band in its place. Or, the said compound band
may be enclosed in a sheath 4 of suitable textile or flexible material, for example
canvas, and placed either as just described, or as in the example shown in Figs. 11
and 12 inclusive, be embedded in the thickened portion or tread of the tyre which
may be of india rubber or an elastic substitute therefor.
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 :-
1. A pneumatic tyre having a contractile tread so constructed that upon placing
the tyre upon a wheel and inflating it, the tread will readily expand in diameter so
far as necessary and on deflation of the tyre the said tread will contract tightly upon
and around the wheel so as to constitute, whilst the tyre is deflated, an efficient solid
elastic tyre as set forth.
2. A pneumatic tyre the tread portion of which is provided with a contractile band
which when in place on a wheel is under tension and is held in its fully distended
condition by the internal air pressure of the tyre so that on deflation of the tyre, the
tread portion thereof will be caused to contract around and upon the wheel,
substantially as described.
3. The combination with a pneumatic tyre provided with a self gripping band of
the kind herein referred to fór securing the tyre upon a wheel as herein set forth, of
a contractile band constructed substantially as herein before described placed upon and
around the said self gripping band substantially as and for the purposes set forth.
4. A pneumatic tyre provided with a contractile band constructed and arranged
substantially as hereinbefore described with reference respectively to and shown in
Figs. I to 4 inclusive, or modified according to Fig. 4; in Fig. 5; in Fig. 6; in
Figs. 9 and 10 and Figs. 11 and 12 of the drawings annexed.
5. A pneumatic tyre the tread of which is provided with an inextensible but
contractible band constructed and arranged substantially as hereinbefore described
with reference respectively to and shown in Figs. 7 and 8 and in Figs. 11 and 12 of
the drawings annexed.
6. The improved pneumatic tyres constructed and applied as shown in and
described with reference to Figs. 1 to 4 inclusive, in Fig. 5; and in Fig. 6 of the
annexed drawings.