BACKGROUND OF THE INVENTION Pneumatic shaped solid tires are known in the prior art and are used to replace pneumatic tires in many industrial applications, such as forklifts, baggage carts, and catering vehicles. Solid tires offer the advantages of increased load-bearing capabilities and elimination of the possibility of dangerous blow-outs and costly flat tires.

A typical prior art pneumatic shaped solid tire is illustrated in partial cross-sectional view in FIG. 1 and indicated generally at 10. The outer portion 12 of the tire 10 is a tread rubber compound which is compounded to give wear and grip to the tire, and is maximized for high abrasion, high high tear resistance and strength, and low rolling resistance. Typical prior art treads 12 are formed from black compound, comprising a mixture of natural rubber (which can be contain a ratio of synthetic rubber), carbon black, a cure system, an aging system, and a plasticity system for the vulcanization process. Other tread compounds are known in the prior art. For example, a white compound is sometimes used for the tread 12, which is the same as the black compound but has white silica substituted for the carbon black. Beneath the tread compound 12 is a hard base rubber layer 14 which is used to grip the rim of the wheel

(not shown) upon which the tire 10 is mounted and to support the tire 10 upon this rim. A typical prior art material used for the hard base rubber layer 14 is known as cording compound, which comprises synthetic rubbers (and possibly a ratio of natural rubber), long-length fibers, carbon black, a cure system, and an aging system for the vulcanization process. The cording compound is compounded for hardness and high modulus. The tire 10 may also have a bead 16 on each side of the tire 10, located near the inside perimeter of the tire 10. The bead 16 provides strength to the tire at the intersection with the lip of the rim upon which the tire 10 is mounted. The beads 16 may be pneumatic beads which may be assembled with ply fabric, for example.

Alternatively, the beads 16 may comprise steel round wire which may be assembled in a cage.

Because the tread compound 12 is somewhat hard in order to provide high wear resistance and low rolling resistance, and because the layer 14 is also hard in order to provide structural rigidity to the tire at its mounting location, it has been found that the tire 10 may not provide a soft enough ride in some industrial applications, such as with forklifts carrying fragile cargo. The vibration transmitted through the tire 10, to the forklift and to the cargo, caused by the tire 10 rolling over surface irregularities, is unacceptable for some applications. Thus, a second embodiment prior art tire is illustrated in FIG. 2 which alleviates some of these problems, and is indicated generally at 20. The tire 20 includes the tread compound layer 12, the hard base rubber layer 14, and the beads 16 of the tire 10. However, a soft cushion rubber layer 22 is formed between the tread compound 12 and the hard base rubber layer 14. The cushion rubber layer 22 is formed from a softer rubber compound in order to absorb a portion of the shocks and vibrations produced by the tire 20 rolling over irregular surfaces. This translates into a much softer and

less jarring ride for the piece of equipment riding upon the tires 20.

While prior art solid tire designs such as the tires 10 and 20 illustrated in FIGS. 1-2 provide adequate performance in industrial settings, they suffer from the problem that a majority of the load weight is supported by the relatively small portion of the tire which lies directly under the wheel at any given time. In other words, the portions of the tire to either side of the wheel and above the wheel (which comprises a majority of the tire) do not support any appreciable portion of the load weight. By concentrating the load weight on a small section of the tire at any given time, the tire is forced to endure much higher stresses than would be the case if the load were evenly distributed around the entire tire. Such increased effective loading results in faster tire wear than would be the case with distributed loading.

There is therefore a need for a solid tire design which provides for more effective distribution of the load weight throughout the entire tire, thereby providing higher load capacity for the tire and a more effective tire system. The present invention is directed toward meeting this need.

SUMMARY OF THE INVENTION The present invention relates to a steel banded solid tire in which a 360° steel band is embedded within the solid tire below the tread compound layer. By including such a steel band within the solid tire, the tread is given a 360° reinforced platform which distributes the load forces throughout the entire tire and provides better load capacity and a more effective tire system than prior art solid tire designs.

In one form of the invention, a solid tire is disclosed, comprising an outer tread layer formed from a tread compound, said tread layer having an outer tread surface and an inner tread surface; a 360 degree rigid band having an outer band surface facing the inner tread surface, and an inner band surface; a cushion layer formed from a relatively soft compound, said cushion layer having an outer cushion surface facing the inner band surface, and an inner cushion surface; a base layer formed from a relatively hard compound, said base layer having an outer base surface facing the inner cushion surface, and an inner base surface; and at least one circumferential bead formed in the base layer; wherein the inner base surface is sized and shaped to fit upon a wheel with substantially no air space therebetween; and wherein said 360 degree rigid band is operative to distribute load forces throughout the tire.

In another form of the invention, a solid tire is disclosed, comprising an outer tread layer formed from a tread compound, said tread layer having an outer tread surface and an inner tread surface ; a 360 degree rigid band having an outer band surface facing the inner tread surface, and an inner band surface; and a base layer formed from a relatively hard compound, said base layer having an outer base surface facing the inner band surface, and an inner base surface; at least one circumferential bead formed in the base layer; wherein the inner base surface is sized and shaped to fit upon a wheel with substantially no air space therebetween; and wherein said 360 degree rigid band is operative to distribute load forces throughout the tire.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional perspective view of a first embodiment prior art solid tire.

FIG. 2 is a partial cross-sectional perspective view of a second embodiment prior art solid tire.

FIG. 3 is a partial cross-sectional perspective view of a first embodiment solid tire constructed according to the present invention.

FIG. 4 is a partial cross-sectional perspective view of a second embodiment solid tire constructed according to the present invention.

FIG. 5 is a partial cross-sectional perspective view of a steel band configured according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

A first embodiment solid tire constructed according to the principles of the present invention is illustrated in partial cross-sectional perspective view in FIG. 3, and indicated generally at 30. Like the prior art tire 10 of FIG. 1, the tire 30 includes a tread rubber compound 12, a hard base rubber layer 14, and beads 16. However, unlike the tire 10, the tire 30 includes a 360° steel band 32 formed just below the tread compound 12. The steel band 32 is illustrated individually in FIG. 5.

The function of the steel band 32 is to provide a 360° reinforced platform for the tread compound 12 which serves to distribute the load forces from the vehicle throughout the tire 30. With the inclusion of the steel band 32, the majority of the load forces are no longer concentrated in the portion of the tire lying directly below the vehicle wheel. Instead, the 360° steel band 32 causes a distribution of the load forces throughout the tire 30, such that the load not only rests upon the lower portion of the tire 30, but also"hangs"from the upper portions of the tire 30. By distributing the load in this manner, the effective load weight on any given portion of the tire 30 rotated below the wheel is considerably less than would be

the case if the steel band 32 were not present (such as with the prior art tire 10). Thus, the tire 30 provides greater load capacity and a more effective tire system.

A second embodiment solid tire of the present invention is illustrated in a partial cross-sectional perspective view in FIG. 4 and indicated generally at 40. The second embodiment tire 40 is similar to the first embodiment tire 30, however, a cushion rubber layer 22 is inserted between the steel band 32 and the hard base rubber layer 14. The inclusion of the cushion rubber layer 22 provides the soft ride benefits discussed hereinabove with respect to FIG. 2.

Inclusion of the steel band 32 beneath the tread compound layer 12 in the tire 40 provides the same benefits described hereinabove with respect to tire 30.

In a preferred embodiment, the steel band 32 is formed from C1015 steel which is 13-18 carbon and 30-60 manganese.

The steel is preferably 5/16 of an inch thick and is recessed from the tire sidewall by 1/4 inch 1/8 inch.

Those having ordinary skill in the art will recognize that the benefits of the present invention result from providing a 360° reinforced platform under the tread compound 12.

Therefore, although the preferred embodiment construction of the band 32 is steel, other materials will work equally well. For example, other metals, such as aluminum, may also be used. Furthermore, non-metallic materials may be used for the band 32, such as a high-strength plastic, carbon fiber, etc. It is only necessary that the material used for the band 32 have high enough strength to provide a 360° reinforced platform under the tread compound 12.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.