Improvements in Pneumatic Tyres.
Year: 1898

page_text: Date of Application, 15th Nov., 1898
Complete Specification Left, 14th Sept., 1899-Accepted, 14th Oct., 1899
Improvements in Pneumatic Tyres.
I, ELEAZER KEMPSHALL, of 170, Summer Street, Boston, in the State of Massa-
chusetts, United States of America, Gentleman, do hereby declare the nature
of this invention to be as follows:-
This invention relates to pneumatic tyres, and more particularly to pneumatic
tyres of the kind or class known as "single-tube" tyres.
In pneumatic tyres a layer of spongy or cellular rubber has sometimes been
placed between the tread surface and the airtight tube forming the air chamber,
so that the tread portion of the tyre is thicker than the sides thereof and affords
increased protection against puncture without undue increase in weight or loss
of flexibility or resiliency. When such tyres are in use, however, there is a
tendency for the thickened tread portion to be pressed inward so as to occupy
part of the space normally occupied by the air chamber. The tyre is thus some-
what flattened and the portions adjacent to the edges or sides of the tread
portion are brought near to the ground and exposed to wear and are liable to be
punctured. Moreover if such tyres be punctured through the tread portion,
although the spongy or cellular rubber will, by the expansion of the walls of the
few cells into which the air from the air chamber first enters, prevent any escape
of air therethrough, yet it has been found that such air will penetrate along
or through the inextensible fabric employed in the construction of the tyre and
may escape at the side or other weak part of the tyre where wear or other circum-
stances may have caused said fabric to be exposed through the outer covering of
vulcanized rubber. An air leak of this kind is, as is well known, almost
impossible to locate or repair.
Now the object of my invention is to overcome these disadvantages and to
provide a pneumatic tyre with a tread, having a layer of spongy rubber therein,
that will be always maintained in its proper position and will form. so to speak,
a resilient peripheral ridge or projection that will separate the walls of the air
chamber from the ground under all ordinary conditions of use. Further objects
of my invention are to prevent leakage of air in the manner above referred to
and generally to provide a tyre that will be much less liable to puncture than
tyres as heretofore constructed.
According to my invention I employ two separate strips or tubes of in-
extensible fabric, one of which forms an inner lining for the outer vulcanized
indiarubber covering or wearing surface of the tyre, and the other of which forms
an outer lining for the tube forming the air chamber. The layer of spongy
rubber is placed between these two strips adjacent to the tread surface, and the
arrangement is such that the thickened tread portion thus formed cannot be
pressed into the space normally occupied by the air-chamber when the tyre is
inflated. Moreover this tread portion is held in such a position that even when
the tyre is deflated the said portion will afford a resilient bearing or tyre, and
so enable the vehicle to which it is applied to be ridden without discomfort to
the sidon

page_text: One or both the said inextensible strips is or are wholly or partially formed
of a special air-tight fabric, such as manilla paper or glazed muslin, so that if
the same be perforated, air coming from the air chamber will not be able to
escape by penetrating to the side or other weak part of the tyre. Moreover
those two separate strips afford greatly increased protection against puncture.
Although I have described my invention as applied to a single tube tyre,
it is obvious that by suitable modifications it may be applied to "double tube"
tyres, or to so-called "tubeless" tyres.
"
"
I do not confine myself to any special kind of fabric, as any appropriate
material may be employed for my purpose.
Tinted thi 15th
1100o
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in Pneumatic Tyres,
I, ELEAZER KEMPSHALL, of 170, Summer Street, Boston, in the State of Massa-
chusetts, United States of America, Gentleman, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
This invention relates to pneumatic tyres of the kind in which a layer of
spongy or cellular rubber is arranged between the tread surface and the air
chamber, thus affording increased protection against puncture without unduly
increasing the weight or diminishing the flexibility or resiliency of such tyres.
When tyres of this kind are in use, however, there is a tendency for the
thickened tread portion to be pressed inward so as to occupy part of the space nor-
mally occupied by the air chamber. The tyre is thus somewhat flattened and the
parts thereof adjacent to the edges or sides of the tread portion are brought near
to the ground and exposed to wear and are liable to be punctured. If such
tyres be punctured through the tread portion, the spongy or cellular rubber
will, by the expansion of the walls of the few cells into which the air from the
air chamber first enters, prevent any escape of air through the tread portion. But
it has been found that such air will penetrate along or through the inextensible
fabric employed in the construction of the tyre and may escape at the side or
other weak part of the tyre where wear or other circumstances may have caused
said fabric to be exposed through the outer covering of vulcanized rubber. An
air leak of this kind is, as is well known, almost impossible to locate or repair.
In the Specification of British Letters Patent No. 25028 granted to me under
date of the 15th day of June 1898 I have shown means which, in part, overcome
this last mentioned disadvantage, consisting in arranging a strip of air-proof
material between the layer of spongy rubber and the air chamber. It has how
ever been found that air from the air chamber may pass along the surface of
the said strip and so reach the side of the tyre or other weak part thereof.
Owing to the friction caused by the constant bending of the sides of the tyre
when it is being ridden, the edges of the said strip were often detached from
the fabric at the sides of the tyre, so that the said spongy rubber was very liable
to be displaced. Moreover the detached edges were liable to crease or curl over
and to damage the walls of the air chamber.
Now the object of my present invention is to overcome these disadvantages
and to provide a pneumatic tyre with a tread portion, having a layer of spongy
rubber therein, that will be always maintained in its proper position and will
form, so to speak, a resilient peripheral ridge or projection that will separate the air

page_text: chamber from the ground under all ordinary conditions of use. Further objects
of my invention are to prevent leakage of air in the manner above referred to,
and generally to provide a tyre that will be much less liable to puncture than tyres
as heretofore constructed. My improved tyre is also capable of being ridden
with safety when deflated.
According to my invention I employ two separate tubes, strips or layers of
inextensible fabric, one of which forms an inner lining for the outer vulcanized
indiarubber covering or wearing surface of the tyre, and the other of which
forms an outer lining for the air chamber. The layer of spongy rubber is placed
between these two strips adjacent to the tread surface, and the juxtaposed sur-
faces of the two strips are solutioned or otherwise firmly attached together, the
arrangement being such that the thickened tread portion thus formed cannot
be pressed into the space normally occupied by the air chamber when the tyre is
inflated. Moreover this tread portion held in such a position that even when
the air chamber is deflated, the said portion will afford a resilient bearing or
tyre, and so enable the vehicle to which it is applied to be ridden without dis-
comfort to the rider. The inextensible fabric being tubular or nearly so presents
large surfaces to be solutioned together or otherwise united and in this respect
my improved tyre differs from other tyres of the kind referred to. One or both
of the said inextensible strips are wholly or partially formed of a special air-
proof fabric, such as manilla paper or glazed muslin; or such strips may be
rendered air-proof or practically air-proof by being treated with paraffin or other
suitable substance, or by being woven in a particular manner. Therefore, if the
said strips be perforated, air coming from the air chamber will not be able to
escape by penetrating to the side or other weak part of the tyre, because it will be
imprisoned between the two strips. Moreover these two separate strips afford
greatly increased protection against puncture.
In order that my invention may be clearly understood and readily carried
into effect I will describe the same more fully with reference to the accompany-
ing drawings in which:-
16
Figure 1 is a cross section of a single tube" tyre constructed according to
my invention.
t
"
"
Figure 2 is a similar section showing the aforesaid strips or tubes separately..
Figures 3, 4 and 5 are other views, similar to Figure 1, showing my inven-
tion applied respectively to a tubeless tyre and to two forms of double
tube" tyre, viz. the well known "Welch-Dunlop" tyre and the "Olincher "
tyre. The outer cover or jacket only is shewn in Figures 4 and 5.
In all the figures like letters of reference indicate similar parts.
A is the tube or strip of india rubber adapted to constitute the air chamber,
B is the layer of spongy rubber, and C is the outer covering of vulcanized india
rubber. is the inner strip or tube of inextensible fabric, and b is the outer
strip or tube of such fabric.
"
In constructing a single tube " ог "tubeless" tyre according to my inven-
tion, the strip a is preferably placed around the air-tube A (Figure 1), or upon
the strip of india rubber A forming the inner lining of a tubeless tyre (Figure 3),
which latter is then partially vulcanized. The layer of spongy indiarubber-
which preferably has also been previously partially vulcanized is then placed
in position, and the outer strip 6 is laid over the same and over the strip a, as
shown. To this strip 6 a coating of unvulcanized indiarubber is applied, and
the whole is then vulcanized to form a finished tyre.
The parts of the two strips a and b which are juxtaposed thus become firmly
united, and hence the spongy rubber between the said strips at the tread portion
of the tyre cannot be displaced. Moreover, as the strips are inextensible, it is
obvious that the strip a, being firmly attached at the sides to the strip b, will
not permit the spongy rubber to be forced inward so as to occupy a portion of
the space normally occupied by the air chamber. This forcing inward of the
cushioned tread portion of the tyre cannot occur even when the tyre is deflated;

page_text: and consequently my improved tyre can, if necessary, be ridden in a deflated
condition without discomfort to the rider or damage to the tyre, because the said
cushioned tread portion forms a projecting ridge which constitutes a resilient
tyre and maintains the other portion of the tyre-proper above the ground.
may
As herein-before stated, a part or the whole of one or both of the strips a
and b is formed of an air proof material. Preferably the whole of the outer
strip is formed of such material, as indicated in the drawings. I also
form the inner strip a entirely of such material, but this is not necessary and
such strip may be formed of ordinary fabric or partly of such fabric and partly
of air proof fabric. In Figures 1 and 2 I have shewn an inner strip a having
only that portion a¹ adjacent to the tread surface formed of air-proof fabric.
By this construction, if a puncture should take place, and the inner and
outer strips, and the layer of spongy rubber, be thereby perforated, any air
passing along the inner strip to the side of the tyre will be stopped and prevented
from escaping by the outer air-proof strip 6. Such air can therefore only pass
along or around the tyre inside such outer strip; and as this strip is only
likely to be perforated at the tread portion where its interior surface is covered
with the spongy rubber, the air could not escape through such perforation be-
cause any passage of air toward the same would immediately distend the walls
of the adjacent cells of the spongy rubber and cause them to close or stop the:
said perforation. No objectionable leak of air can therefore take place when
my improved tyre is punctured.
It will be noticed with reference to the tubeless tyre shown in Figure 3, that
a piece or strip of pure india rubber is placed between the ends or edges of the
strips a and b, in order to render the said edges air-proof, and prevent the escape
of air that may have penetrated between such strips. Any other means may
however be employed for this purpose.
Referring now to Figures 4 and 5, which show my invention applied to the
covers or jackets of double tube tyres, it will be seen that the two strips are
formed in one piece or tube, one portion, a, of which is folded inward upon the
other portion, b. The cushion of spongy rubber, and the wires d (Figure 4),
or the filling material of the beads (Figure 5), are enclosed between the said
portions at their proper positions. It is obvious however that, if desired, the
said strips may be separate as described with reference to Figure 3. Both the
portions or strips a and b are preferably formed of air-proof material. The outer
portion is covered with a layer of unvulcanized indiarubber, and the whole
cover or jacket is vilcanized as above described with reference to single tube
and tubeless tyres.
It will be readily, understood that instead of applying the spongy rubber
cushion B and the inextensible strips a and b to the cover or jacket of a double
tube tyre, I may apply them to the air-tube thereof.
I wish it to be understood that I do not confine myself to the use of any
special kind of fabric or of air-proof material, as any appropriate material may
be employed for my purpose. For example, I may employ textile fabric com-
posed of thin and closely woven threads that will, in conjunction with the outer
covering of vulcanized india rubber, be practically air-proof. Moreover, although
I have described one method of manufacturing my improved tyre or tyre cover.
it will be readily understood that any other suitable method may be employed
for the purpose.
It is also obvious that either the outer or the inner strip, or both, may be
duplicated. This will be desirable in tyres for tandem bicycles or motor cars,
for instance.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. In a pneumatic tyre, the combination with a cushion of spongy rubber of
6

page_text: two tubes, strips or layers of inextensible fabric enclosing the said cushion and
united substantially as described.
2. A pneumatic tyre constructed and arranged substantially as described with
reference to any of the examples illustrated in the accompanying drawings for
the purposes specified.
"
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.