Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-02-24
2002-08-20
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S148000, C156S169000, C152S516000, C152S526000
Reexamination Certificate
active
06436215
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The invention relates to reinforced resilient pneumatic tires and more particularly to a vehicle tire reinforced by a thin annular composite band which enables the tire to run in an unpressurized condition and to provide greater puncture resistance for the tire. More particularly, the invention relates to a pneumatic tire in which the band element is formed of twisted material strips having fibers which are oriented within the band to extend across the neutral axis of the band and not fall within the axial plane of the neutral axis to provide the band with enhanced ability to resist interlaminar shear stresses and provide enhanced inflated and uninflated banded tire durability and puncture resistance.
2. Background Information
Various tire constructions have been devised over the years which enable a tire to run in an under-inflated or non-inflated condition, such as after receiving a puncture and loss of pressurized air, for extended periods of time and at relatively high speeds. This enables the vehicle operator to safely drive the vehicle to an appropriate location for repair or replacement of the punctured tire. Certain of these safety tires, referred to as “run flat tires”, have been successful for certain applications and certain types of tire constructions. Most of these run flat tires achieve their run flat capability, by the placement of reinforcing layers or members of relatively stiff elastomeric material in the side walls of the tire which enable the tire to support the vehicle weight even with the complete loss of internal air pressure. Examples of such prior art run flat tire constructions which use such sidewall inserts are shown in U.S. Pat. Nos. 3,911,987; 3,949,798; 3,954,131; 4,067,372; 4,202,393; 4,203,481; 4,261,405; 4,265,288; 4,287,924; 4,365,659; 4,917,164; and 4,929,684.
In addition to these prior art run flat tires, various run flat tire constructions have been developed which utilize a thin annular band which extends circumferentially throughout the tire beneath the tread area. Examples of such banded run flat tires are shown in the following patents.
U. S. Pat. No. 4,428,411 describes a method to make a particular band for use in a run flat tire which uses a series of side-by-side elements in the form a helix. The band has hoop compression as against a conventional breaker belt that has no significant compressive strength but is used only to resist tension loads endured by the tire when pressurized.
U.S. Pat. Nos. 4,673,014 and 4,794,966 teach a method to acquire desirable prestressing in a fabricated band made of helical elements. Physically bending the larger diameter helix element around a smaller mandrel and securing it with a resin impregnated tape acquires a desirable level of prestressing.
U.S. Pat. No. 4,456,048 teaches a method of acquiring a change in band stiffness as a function of deflection. The band has a lower stiffness for normal pressurized operation and has a higher stiffness to support load when the tire is uninflated and experiences larger deflection.
Japanese Patent application No. JP 63141809 discloses a run flat tire having a banded element which is formed of layered strips of materials, such as an arramed filament which is impregnated with a high elasticity epoxy resin, which after hardening provides a stiffened band. The tire of this disclosure requires that elastomeric side wall inserts be utilized in combination with the band in order to achieve the desired run flat characteristics.
Other run flat banded pneumatic tires are shown in U.S. Pat. Nos. 4,111,249; 4,318,434; 4,428,411; 4,459,167; and 4,734,144.
Banded tires have been fabricated with band materials made of steel, aluminum, titanium, and epoxy and thermoplastic composites with glass, KEVLAR (aromatic polyamide) and graphite fiber reinforcement. The common failure mode with such lightweight, economical laminate band constructions is interlaminar shear within the band's primary bending neutral axis. This is a fatigue failure and is directly related to the spectrum of cyclic operating stress. As in all fatigue failures, the lower the stress, the longer the operating life. This problem of fatigue failure occurring along the neutral axis of the band resulting in interlaminar shear can be reduced by the prestressing the band during its manufacture, as described in pending patent application Ser. No. 08/782,364.
Numerous prior art pneumatic tires have been provided with an annular band usually of metal, to resist puncture by sharp objects protruding through the tread area. Although these prior art puncture resistant tires utilizing a metal band provide the desired puncture resistance, in most cases, the metal band effects the ride characteristic of the tire and the life expectancy thereof.
Thus, it is desirable to provide a band element for run flat pneumatic tires and for pneumatic tires having greater puncture resistance, with increased resistance to interlaminar shear stress in the inflated deflected banded tire, the uninflated deflected banded tire and the condition of a banded tire encountering a road surface anomaly, which is accomplished without materially increasing the difficulty of the manufacturing process for producing the band element and without materially increasing the cost thereof. The band element of the present invention achieves these results.
SUMMARY OF THE INVENTION
Objectives of the invention include. providing an improved pneumatic tire that is substantially similar in ride, comfort, durability and operation as conventional pneumatic tires, yet which is able to be operated safely at reasonable speeds and for a sufficient number of miles after loss of internal pressurization.
Another objective of the invention is providing such a pneumatic tire and band element therefor which has enhanced load carrying capability, improved endurance by minimizing band stress, and in particular minimizes interlaminar shear stresses heretofore resulting in destruction of the band element.
Still another objective is to provide such a band element for use in a pneumatic tire in which the band element is formed of usual tape strips having longitudinally extending fibers embedded in a resin with the tape being arranged during the construction of the band so that a substantial portion of the fibers extend over the neutral axis of the band which is the area most susceptible to interlaminar shear.
A still further objective of the invention is to provide such a band element for run flat tires in which the individual tape strips which form the band have longitudinally extending fibers embedded within a resin, are twisted into a cylindrical configuration and then pultrated into a rectangular configuration for subsequent wrapping about a mandrel into an annular band having one or more inner and outer layers of the conventional flat tape strips extending about the intermediate pultrated strip layers.
Another objective of the invention is to provide such a band element wherein a plurality of the flat strips containing the longitudinally extending fibers embedded in the resin matrix, are placed in juxtaposition prior to being twisted into a cylindrical configuration for subsequent pultration into a rectangular configuration to provide a stronger layer having the fibers extending across the neutral axis to increase resistance to interlaminar shear.
A still further objective of the invention is to provide such a run flat tire which has increased puncture resistance from the tread contacting road hazards, which can be manufactured at a cost and weight competitive with conventional non run flat tire constructions and which will permit the elimination of a spare tire conventionally required in automobiles thereby providing a cost saving to vehicle manufacturers and owners.
These objectives and advantages are improved by the method of the present invention, the general nature of which may be stated as including a method of forming a thin annular band for embedding in a crown portion of a pneumatic tire including the steps of providing
Kirby James M.
Markow Edward G.
Spragg Charles D.
Ball Michael W.
Bridgestone Firestone North American Tire, LLC
Fischer Justin
Palmer Meredith
Sand Michael
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