Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a tire casing structure, and
particularly concerns a tire casing provided with a novel
puncture-sealing layer.
The development of more durable and safe tires plays an
important role in the field of automotive parts. Many car
accidents, sometimes accompanied by very serious injuries and
even death, are caused by the puncturing and consequent blow-out
of tires. Even if such an accident does not lead to injury, it
is still rather troublesome to remove the blown-out tire and to
install the spare tire or to make emergency repairs, the extent
of which depends upon the degree of the puncture.
Prior tire casing structures of the general type are shown
in Iknayan, U.S. Patent No. 2,699,194 in which an inner tube has
spaced-apart rubberized fabric plies. Each ply comprised
parallel cords which extend in the same direction. One of the
fabric cords had cords extending in one direction while the other
ply had cords extending at 50 relative to that first direction.
This prior art utilized the tube to span a brake in the casing
and thus to prevent the tire from blowing out.
Villard, U.S. Patent No. 1,572,053 taught a shoe therein
with its original inner surface outermost, the shoe consisting of
a body made substantially of elastic material and coextensive
with the inner surface of the casing. Should the air ~ithin the
tire exhaust, the compressed shoe will maintain the tire in an
operative condition.
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Pixley, U.S. Patent No. 1,431,596 disclosed an inner tube
for tires, which inner tube was reinforced by a suitable number
of layers of fabric throughout the greater portion of its
transverse circumference, the reinforcing layers being arranged
so that there is a greater thickness of reinforcement and rubber
within the zone which is disposed adjacent to the thread of the
shoe or casing.
Murphy, U.S. Patent No. 919,915 disclosed an inner tube for
use in tires for automobiles. The tube body was formed of one or
more layers of woven, partially-elas-tic fabric with a rubber
compound being forced into the meshes of the fabric and forming
an outer and an inner covering for the fabric.
Spancer, U.K. Patent No. 15640 also ~isclosed an inner tube
for the wheels of road vehicles. The inner tube taught by
Spancer was characterized by the rubber at or about the ends or
edges of the strip or strip of canvas or fabric being thickened
and the intervening circumferential strip consisting of rubber
only made as thin as possible consistent with the necessary
strength.
Although the above-described prior patents all were a
success in providing a necessary strength for the inner tube,
they still suffered the same problem that, once the inner tube
was pierced through by a pointed object, no puncture-sealing
layer can be effected around the pierced object so as tightly to
bind the object without air-pressure escaping therefrom.
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Therefore, emergency operation was still needed for safety
purposes.
An object of a general aspect of this invention is to
provide a tire casing having a puncture-sealing layer which can
automatically seal a puncture by having rubberized interwoven
flexible cords that engage around a puncturing object.
An object of another aspect of this invention is to provide
a novel tire casing, which can run a long distance a~ter being
punctured by a sharp object.
By one broad aspect of this invention, a tire casing is
provided having an inside surface, comprising a tubular puncture-
sealing layer extending over the inside surface thereof, the
tubular puncture-sealing layer being made of interwoven flexible
cords both the layer and the cords being rubberized and secured
to the inside surface; whereby an object puncturing the tire
casing and the tubular puncture-sealing layer and projecting
between the cords will be tightly engaged by the cord~ around the
object, thereby to seal the puncture with substantially only a
small amount of air escaping therefrom.
It is preferred that the puncture-sealing layer be
adhesively connected to the inside surface of the tire casing.
The puncture-sealing layer preferably further comprises an
annular, all-rubber portion integrally formed along the opposing
edges of the puncture-sealing layer during rubberization thereof,
for positioning directly over a rim area.
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In the accompanying drawings,
Fig. 1 is a perspective view of a tire according to one
embodiment oE this inventi,on, with several nails inserted
therein;
Fig. 2 is a cross-section view of another embodiment of the
tire casing according to this invention;
Fig. 3 is a cross-section view of yet another embodiment of
the tire casing;
Fig. 4 is a fragmentary sectional view taken on lines 4-4 of
Fig. 1, showing a tire casing of an embodiment of this invention
having been punctured by a nail; and
Fig. 5 is a schematic view showing the sealing effect of
rubberized interwoven cords when a nail punctures through the
puncture-sealing layer of the tire casing according to an
embodiment of this invention.
Referring now to Figs. 1 and 2, a preferred embodiment of a
tire casing 1 is shown provided with a puncture-sealing layer 2
according to an embodiment of this invention.
As illustrated in the drawings, the puncture-sealing layer 2
is made of flexible interwoven cords 3 (as best seen in Fig. 5),
which are formed in a sheet and are rubberized into a tubular
shape adapted to be secured to the inner wall of the tire ca~ing
1 with or without applying an adhesive therebetween since the
puncture-sealing layer 2 will be stretched tightly to contact the
inner wall of the tire casing 1 after being inflated. The cords
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3 selected to be interwoven into the sheet must be flexible and
tough so that once they are interwoven and ruhberized, a
desirable cohesive force in the woven cords 3 is present.
The interwoven cord-sheet is rubberized into a tubular form
and is disposed within the tire casing 1. When the puncture-
sealing layer 2 is inflated therein, it will automatically be
combined with the inside surface of the casing 1.
As seen in Fig. 3 and Fig. 4 it is ~elieved -that when a
sharp object, illustrated here as a nail 6, pierces the -tire
10 casing 1 and the puncture-sealing layer 2, at the moment the
sharp object pierces the casing, some air will leak out, and
immediately the puncture-sealing layer 2 will work to seal the
opening. As is better shown in Fig. 5, the rubberized interwoven
cords 3 can rapidly bind the nail 6 tightly. This rapid binding
is due to the flexibility of the interwoven cords, since the high
elasticity of the rubber causes almost instantaneous recovery to
its original state after being punctured and locally deformed by
such a nail 6. The result is that the nail 6 is snugly gripped
by the puncture-sealing layer 2 of the rubberized cords 3 as
shown in Fig. 4.
Referring to Fig. 3 in which another embodiment of this
invention is shown, the puncture-sealing layer 2 includes an
annular portion 20 integrally formed along the opposing edges 21
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and 22 of the puncture-sealing layer during rubberization
operation thereof. This annular portion 20 is constituted
entirely of rubber material and is to be directly positioned over
the rim area 5 because there is little possibility that the
annular portion 20 will be punctured by any sharp objects.
A test to determine the usefulness of the invention is
conducted by the following procedure:
seven nails with lengths of at least 1 1/2" are inserted
into a tire casing which was mounted on the rear wheel of a
10 motorcycle, e.g. that known as a SCOOTER 90 motorcycle. The
distance between each adjacent two nails was less than 20 cm, and
the load of the motorcycle was 130 kg (two persons riding
thereon). The tire casing to be tested was inflated to a
pressure of 3 kg/cm2. After a long-distance ride of 37 miles,
the tire pressure was slightly lower than 3 kg/cm2 due to a fact
that a small amount of air leakage occurred when pulling out the
nozzles of the pneumatic pump and the pressure gauge from the
tire.
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