Safety tire having automatic inflating means in the event of tears or punctures

Claim 2

In a pneumatic tire having a tread band and a casing, the improvement which comprises providing inside said casing an inflatable structure comprising an annular band of deformable sealing material capable of sealing a hole in the casing and having a width at least equal to the width of the tread band of said tire, wherein said annular band is situated in a first position out of contact with the inner surface of the casing when the tire is in working condition and means for inflating said structure to displace said annular band to a second position in contact with the inner surface and below the tread band, said means comprising a bottle for compressed air or gas mounted eccentrically on the rim to which the tire is fitted allowing for generation of a centrifugal force upon the rim when the compressed air or gas flows from said bottle to indicate the occurrence of a puncture or a tear in the tire.

Claim 3

The pneumatic tire of claim 1 wherein said liquid gas is a fluoro-chloro hydrocarbon.

Claim 4

The pneumatic tire of claim 1 wherein said liquid gas is dichlorodifluoromethane.

Claim 5

The pneumatic tire of claim 1 wherein said liquid gas is monochloropentafluoroethane.

Claim 6

In a pneumatic tire comprising a tread band, a casing having an inner surface, an inflatable structure inside said casing situated in a first position out of contact with the inner surface of the casing when the tire is in a working condition and means for inflating said inflatable structure to a second position in contact with the inner surface of said casing, said inflatable structure comprising: an annular band of elastic foam material With prevailingly closed cells, the width of the annular band being at least equal to the width of the tread band of said tire, the thickness of the annular band in the second position being no greater than 20 mm and the moment of polar inertia of the annular band measured with respect to the axis of rotation in said first position being no greater than one fifth of the moment of inertia of the tire devoid of said band; a pair of deformable sidewalls for said annular band each of which, in said first and second position, leans substantially on a corresponding sidewall of said casing and has an outer circular edge secured to a corresponding lateral edge of said annular band, and extending upon the sidewall of the casing up to the corresponding bead of the tire, said annular band being superimposed on said sidewalls when the inflatable structure is in said first position and being displaced, at the second position of the inflatable structure, into contact with the inner surface of the casing below the tread band; and means capable of preventing the flow of tire inflation air from said inflatable structure in the space between the outer surface of the latter and the corresponding inner surface of the casing.

Claim 7

In a pneumatic tire comprising a tread band, a casing having an inner surface, an inflatable structure inside said casing situated in a first position out of contact with the inner surface of the casing when the tire is in a working condition and means for inflating said inflatable structure to a second position in contact with the inner surface of said casing, said inflatable structure comprising: an annular band of elastic foam material With prevailingly closed cells, the width of the annular band being at least equal to the width of the tread band of said tire, the thickness of the annular band in the second position being no greater than 20 mm and the moment of polar inertia of the annular band measured with respect to the axis of rotation in said first position being no greater than one fifth of the moment of inertia of the tire devoid of said band; a pair of deformable sidewalls for said annular band each of which, in said first and second position, leans substantially on a corresponding sidewall of said casing and has an outer circular edge secured to a corresponding lateral edge of said annular band, and extending upon the sidewall of the casing up to the corresponding bead of the tire, said annular band being superimposed on said sidewalls when the inflatable structure is in said first position and being displaced, at the second position of the inflatable structure, into contact with the inner surface of the casing below the tread band; and means capable of preventing the flow of tire inflation air from said inflatable structure in the space between the outer surface of the latter and the corresponding inner surface of the casing.

Claim 8

The pneumatic tire of claim 5 wherein said means capable of preventing the flow of tire inflation air comprises an annular deformable element intended to lean substantially on the sidewalls of said tire and on the rim and provided with two circular edges, each of which is connected to a corresponding lateral edge of said annular band to form a tight annular envelope with said band.

Claim 9

The pneumatic tire of claim 5 wherein said means capable of preventing the flow of tire inflation air comprises an inner circular edge on each of said deformable sidewalls tightly connected with a corresponding bead of said tire.

Claim 10

The pneumatic tire of claim 5 wherein the inflating means are capable of being automatically actuated when a puncture or tear takes place in said casing.

Claim 11

The pneumatic tire of claim 5 wherein the deformable material forming said annular band has an ultimate elongation of at least 150%.

Claim 12

The pneumatic tire of claim 5 wherein said inflatable structure, when in said first position, defines a cavity for the inflation air of the tire which lies substantially between the outer surface of said annular band and the inner surface of the casing.

Claim 13

The pneumatic tire of claim 5 wherein said annular band is produced in a fashion to generate a pre-established pressure inside the cells of the material such that the pressure after the forming operation is substantially equal to the tire inflation pressure.

Claim 14

The pneumatic tire of claim 5 wherein stiffening cords are disposed in at least one layer inside the annular band and in proximity of the inner surface of said band.

Claim 15

The pneumatic tire of claim 5 wherein said deformable sidewalls for said annular band form a single piece with said band and are formed of the same material to produce a single element comprising a central band and sidewalls.

Claim 16

The pneumatic tire of claim 13 wherein the inner circular edge of each sidewall of the element comprising the central band and sidewalls is secured to the corresponding edge of an annular deformable element designed to lean on the rim and forming a tight annular envelope with said element comprising the central band and sidewalls.

Claim 17

The pneumatic tire of claim 13 wherein said inflatable structure further comprises a small carcass of deformable material comprising a central band and sidewalls and provided with beads capable of exerting pressure upon the inner edge of each sidewall of the element comprising a central band and sidewalls to produce a seal between said edge and the corresponding casing bead.

Claim 18

The pneumatic tire of claim 15 wherein the small carcass material has an ultimate elongation of at least 150%.

Claim 19

The pneumatic tire of claim 15 wherein said small carcass comprises at least oNe layer of rubber embedding cords having a substantially radial arrangement and wherein the length of the cords is adequate to allow said inflatable structure to pass from said first to said second position without cord elongation.