BACKGROUND OF THE INVENTION

[0001] The invention relates to structural reinforcements for pneumatic or structurally supported devices for carrying rolling loads. Some illustrative examples of such devices are tires, resilient wheels, wheel-tires, and safety support devices for run-flat systems. The invention is particularly suited for the manufacture of such devices when they are produced by molding processes. More particularly, the invention is directed to a method for forming such reinforcements in a manner which allows the reinforcement to be made independent of the molding process for the device.

[0002] U.S. Application No. 10/618,924, owned in common with the present application, discloses a non-pneumatic resilient wheel-tire having a deformable, load supporting ring and a plurality of webs connecting the ring to a hub. The webs act in tension to transmit the load on the ring to the hub, which is similar to the load supporting and transmitting mechanism of a pneumatic tire. The ring is capable of deforming on the ground contact surface, which provides the tire the ability to transmit traction and steering forces similar to a pneumatic tire. The ring includes a support ply embedded in the ring to control the deformation of the ring when loaded. According to one embodiment, the support ply is a cylindrical wire coil.

[0003] U.S. Patent No. 5,891,279 describes a safety support made of a flexible elastomeric material and having a substantially cylindrical base reinforced with a circumferential reinforcement. The reinforcement ply is oriented substantially at zero degrees which is virtually inextensible, but which allows flexural deformation to facilitate insertion of the support into a tire before mounting on a rim.

[0004] Any of the devices described in the aforementioned application and patent may be made in a molding process, in which the structural elements are formed of the same material injected or caused to flow into a mold. In such a process, a difficulty arises in forming the support ply and correctly positioning it in a mold. It would be convenient to form the support ply in a separate step, and insert and position it in the mold before the material is injected. One may also imagine the useful nature of the invention to provide a precision reinforcement in the crown area of a pneumatic tire. For the sake of simplicity, the term "wheel-tire" will be used herein to describe any of the aforementioned product applications, pneumatic or structural. SUMMARY OF THE INVENTION

[0005| The invention provides a method for forming a wire reinforcement structure having sufficient structural rigidity to allow the reinforcement structure to be made separately from the tire itself, for example, at a more convenient time and to allow insertion in the tire mold. According to the invention, a method for forming a wire reinforcement structure for a wheel tire comprises the steps of:

placing a supporting member on a mandrel;

winding a reinforcing wire on the mandrel over the supporting member

affixing the wire to the supporting member; and,

allowing the wire and supporting member to bond so that the supporting member supports the wire in a circular cross-section structure.

[0006| The wire may be bonded to the supporting member by any or a combination of suitable means such as resistance heating, inductance heating, UV energy, adhesive bonding, and so forth.

|0007] According to one embodiment of the invention, the supporting member comprises a sheet of plastic material wrapped on the mandrel. According to another form of the invention, the supporting member comprises at least one plastic stay or tie placed on the mandrel. In accordance with still another form of the invention, the supporting member includes at least three plastic stays, which are disposed so that respective free ends of the stays extend from an end of the wire coil ,to provide positioning spacers for correctly positioning the supporting member in a mold for making a resilient wheel-tire.

[0008] According to the invention, the step of placing the plastic ties includes placing the ties in equally spaced relation on the mandrel.

[0009] The method according to the invention further comprises the step of providing a mandrel having grooves for accepting the plastic ties.

[0010] According to another aspect of the invention, the method includes the step of applying an adhesive to at least one of the supporting member and the plastic ties, wherein heating the wire activates the adhesive. According to a further embodiment, the adhesive is a UV cured adhesive and includes the step of applying UV energy to the coated wire to activate the adhesive. BRIEF DESCRIPTION OF THE DRAWINGS

[0011 ] The invention will be better understood by reference to the following detailed description in conjunction with the appended drawings, in which:

|00121 Figure 1 is a perspective view of a wire coil reinforcement in accordance with the invention;

|00l3| Figure 2 is a perspective view of a wire coil reinforcement according to an alternative embodiment of the invention; and,

|00l4l Figure 3 is a schematic view of an illustrative apparatus for making the wire coil reinforcement of Figure 2.

DETAILED DESCRIPTION

[0015] A wire coil reinforcement 10 is shown in Figure 1 . The reinforcement 10 is intended to be embedded in the outer supporting band of a non-pneumatic tire of the type described in commonly owned US Patent Application No. 10/618,924, the disclosure of which is incorporated herein by reference. Alternatively, the reinforcement 10 could be configured for embedding in the base reinforcement of a run-flat support ring. The reinforcement 10 is also intended to be embedded in the base of a run-flat support ring. The wire coil reinforcement 10 of the present invention is useful in other tire constructions or tire-like structures, as will be apparent to those skilled in the art, and the description here is meant to be illustrative, rather than limiting.

|00l6| Figure 1 depicts a wire coil 12 wrapped on a supporting member 14, which in the illustrated embodiment is a sheet of plastic material wrapped around the mandrel 20. The Mandrel 20 is shown in Figure 3 which serves either as a form for directly winding the wire or as a support device to properly position the stays. Thus, the mandrel 20 may have a variety of axial cross-sections, and the use of the term mandrel is not intended to limit the definition to any that may be used various technical arts. The wire coil 12 and supporting member 14 are formed in a cylindrical shape, and are intended to be embedded in an outer ring of a resilient wheel tire as described in the aforementioned US patent application. The wire coil 12 and supporting member 14 are not limited to cylindrical shapes, but may be formed with any axial cross-section, such as an axially variable diameter capable of forming a variety of external profiles. By way of illustrative examples, the supporting member 14 and wire coil 12 may have a diameter which is linearly increasing in the axial direction to form a wire coil 12 having a frustoconical shape. The supporting member 14 may alternatively have a barrel shape to permit the wire coil 12 to more closely match the transverse radius of the exterior profiles commonly found in tires, or perhaps to have two axial portions having different radii as may be found in the base section of a run-flat support ring. The supporting member sheet 14 helps to maintain the wire coil in the cylindrical shape so that the wire reinforcement may be readily handled and placed in a mold for forming the wheel tire. An outer edge 15 of the sheet 14 extends beyond the last turn of the wire coil 12, and is disposed to provide a level base for accurately positioning the supporting member in a mold.

[0017] Figure 2 depicts a version of the wire coil reinforcement, in which the supporting member comprises a plurality of stays or ties 16. The stays 16 help maintain the wire coil in the cylindrical shape so that the wire reinforcement may be readily handled and placed in a mold for forming the wheel tire. The free ends 17 of the stays 16 extend beyond the last turn of the wire coil 12, and are disposed to provide a level base for accurately positioning the supporting member in a mold. If necessary, the wire reinforcement 12 may be formed using both the plastic sheet 14 and the stays 16 to form the supporting member.

[00181 Figure 2 has been simplified for clarity by illustrating only a front of the coil and omitting illustration of rear portion of the wire turns. At least one, and preferably a plurality of, stays or ties 14 support the wire 12 in the cylindrical shape. Three stays 14 are illustrated in Figure 1, although it should be understood that a fourth stay opposite the centrally positioned stay in Figure 2 is omitted. According to one aspect of the invention, at least three stays 14 are needed to provide a base for the coil allowing it to stand with a central axis perpendicular to the supporting surface. This is useful in accurately positioning the coil in a mold. Another aspect of using the stays 16 to form the wire coil 12 is that the mandrel 20 may have a simple cylindrical shape, and then stays of any axial cross-section may be positioned on the mandrel 20 to form a variety of finished wire coils 12 as described above.

I0019J The number and spacing of stays 16 is determined as that needed to provide the necessary or desired dimensional stability to the coil. A number of stays other than as shown may be used depending on the size of the coil and size of the wires used. Figure 2 illustrates a wire coil 12 where the stays are oriented parallel to the axis of the mandrel. However, it is conceivable to orient the stays at a predetermined angle or angles to the axis of the mandrel to further improve the stability of the finished wire coil 12. For example, the stays 16 may be oriented at alternating positive and negative angles or a single stay 16 may take the form of the letter X in order to provide increased rigidity of the finished coil 12.

[0020] The stays 14 are bonded to the wire 12, and the wire is preferably embedded in the stays. The stays 14 are narrow bars having a length preferably greater than the axial length of the wire coil to provide the base described above, and having a thickness sufficiently greater that the thickness of the wire 12 to allow the wire to become embedded in the stay.

[00211 The supporting member sheet 14 or stays 16 are advantageously formed of a material that is compatible with the material of the supporting band of such a tire to facilitate bonding and integrating in the load supporting band of a resilient wheel tire. The stays are more efficient when the selected material has a softening temperature grater than the temperature encountered in manufacturing the wheel-tire. For example, manufacture of the wheel-tire using low-pressure casting of chemically reactive components may take place at or near room temperature. However, injection methods for thermoplastic materials may occur at significantly elevated temperatures. In the latter instance, the geometric integrity of the coil 12 is better maintained if the stays 16 do not soften during manufacture. One skilled in the art of molding such materials may easily determine the expected temperature based on prior knowledge of the process or by direct measurements of temperatures, and then select an appropriate material for the stay 16. Another factor to be considered in the choice of a material for the stay 16 is that the stay 16 maintains its integrity during operational use of the wheel-tire. Again, one skilled in the art could easily measure the operating temperature regime using known methods, such as imbedded thermocouples or by computer-aided simulations. The date obtained from such measurements can then be used to specify an optimal material. Preferably, the sheet 14 or stays 16 are formed of the same material as the load supporting band of the wheel, which facilitates bonding to the band and ensures that that the material properties of the stays are compatible with the supporting band material.

|0022| In the case where the wire is affixed to and embedded in the stays 16, this step may be accomplished by preheating the wire as it is wound on the mandrel to a temperature sufficient to melt or soften the stay material and allow the wire to embed into the stay. An adhesive or bonding agent may be applied to the stays 14 during the process for forming the supporting band. In the case where the wire is affixed to the stays by a bonding process, a heat-activated adhesive could be applied to the wire, and activated during the heating step.

[0023J The wire 12 is formed to have sufficient tensile strength to perform the supporting function. Advantageously, steel cord used in tire tread belts has been found to be useful. Steel cord may be coated or treated to facilitate bonding with the material of the stay and the supporting band, as will be appreciated by those skilled in the art. The diameter of the wire may be selected according to the tensile properties needed for the particular wheel.

|0024] Figure 3 illustrates schematically an apparatus for forming a wire reinforcement of the type shown in Figure 2 in accordance with the invention. Those of skill in the art will understand that a supporting sheet 14 may be substituted for the stays 16 described below. The apparatus includes a mandrel 20 attached by a shaft 22 to a motor 24. The mandrel 20 surface includes grooves 26 formed in the axial direction of the mandrel for retaining the stays during the winding process. Alternatively, or in addition to the groves 26, the stays 16 may be retained by various methods including the use of a tacky substance, such as a weak adhesive, or by adding vacuum ports to the mandrel at the locations where the stays are to be placed.

[0025] A wire supply reel 30 feeds wire to a distributor 34 which travels on a reciprocating drive 36 to place the wire 12 on the mandrel with appropriate tension and axial spacing.

[0026] According to one embodiment, an electric contact 40 on wire supply 30 provides electric current to the wire 12 during the winding process. The mandrel 20 has an electrically conductive surface, and the wire 12 wound in contact with the mandrel shorts the electric current, thus allowing current to flow between the contact 40 and the mandrel. Resistance in the wire 12 causes it to heat and embed into the plastic stays 16. When the winding process is complete, the wire 12 and stays 16 are allowed to cool, which bonds the wire to the stays.

[0027] Alternatively, other heating means could be provided, for example, an inductive heater 42 can heat the wire immediately prior to it being laid on the mandrel. Other heating means could be used.

[0028| Heating the wire is preferred as a way to control the resultant heating of the stays or sheet to be sufficient for embedding the wire, but not causing other change to the stays or sheet, for example, allowing the wire to cut through the stay or sheet, or causing a change in shape of the stay or sheet.

[0029] The formed coil 10 may then be removed from the mandrel 20. To facilitate removal, a collapsible mandrel may be provided. The coil 10 is self-supporting, and may conveniently be stored or held until needed for the tire molding process. The coil 10 may also be conveniently handled, in particular, when placing in a mold.