The present invention relates generally to an improved light weight composite tire that can be utilized on rescue or all-terrain vehicles.
Tires for almost every type of vehicle are currently constructed of vulcanized rubber and steel belts. This type of material increases the weight of the tire which increases the amount of power required to move the vehicle to fulfill its intended purpose. For example, tractor tires, which are the approximate size and shape required for use in an all terrain rescue vehicle, weigh hundreds of pounds each which limit their use on thin ice and causes them to bog down in mud and sand. Additionally, tires of that weight require additional buoyancy if the craft is to be used in water.
When tires are only to be used on highways and other solid or paved surfaces, the weight and power requirements do not cause problems that cannot be overcome by increasing the power output of the engine which also increases the weight of the vehicle.
However, there are situations where the weight of the vehicle is of such importance in the overall design that standard rubber tires cannot work. For example, vehicles that must be used on surfaces that cannot support weight such as water, mud, beaches, snow, swamps and thin ice. Another example of the importance of tire weight would be interplanetary probes that travel on surfaces composed of dust that has collected over long periods of time. Even with terrestrial vehicles that must be transported to point of use, weight is still a critical consideration. Standard tires also increase the cost of transport of the vehicle to the location of use.
Tires used in rescue or all-terrain vehicles will both have to support the vehicle with its payload, and provide traction, as well as being light enough as to not render the vehicle unusable by sinking into the surface of its operating medium. The tires themselves can also provide flotation.
The instant invention solves all of these problems.
The instant invention solves the twin problem of weight and strength while providing traction by using composite materials that are structurally applied to support a design weight while simultaneously providing buoyancy.
The use of molding techniques in manufacturing are well known in the art. However, to construct tires that are capable of supporting a vehicle capable of multi-surface use; particular injection techniques of composite materials must be used. The composite material used in the instant invention is a carbon fibre, Kevlar®, S-glass epoxy laminate pressure by vacuum voiding pressure-vacuum in fusion molding. The injection techniques are pressure-die injection molding of thread lugs.
The design is a central support assembly to which two casings, each resembling a half-donut shape are bonded together. In another embodiment, inside the hollow casings are a multiplicity of radial bulkheads which add support to the casings. All parts are typically glued with methacrylate structural adhesive or its functional equivalent.
The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements.
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Central Support Assembly
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First Casing and Second Casing
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Joining the Casings to Central Bulkhead Assembly to Form the Tire
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For clarity, surfaces are typical joined in the following order, which is done in three steps: The first step is to bond the first casing 21 to the first central bulkhead 8. The second step is to bond the second casing 22 to the second central bulkhead 10. The third, and final step, is to bond the two inner surfaces 13,18 of the central bulkheads 8,10 to each other. It should be noted that the flat edge 79 of each radial bulkhead 71 is also bonded to the exterior surface 13,16 of each central support bulkhead 8,10.
While the bonding of flat surfaces are illustrated, it is also contemplated that a tongue and grove, which is well know in the art, on the surfaces could be utilized to increase strength and ease of assembly. The surfaces that the tongue and grove concept could be useful for: surfaces 7,11,13,15,17,18,19. However, the use of methacrylate for bonding should provide satisfactory strength for use in a rescue vehicle.
Traction on Hard Surfaces
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Radial Bulkheads
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The more radial bulkheads 71 that are used, the more the volume of each chamber 75 will be reduce. This will therefore reduce the buoyancy by increasing the weight of the tire and reducing the air space. However, it should be noted that when using composite materials the increase in weight is not significant, and a solid composite tire 1 is even contemplated in the case of extreme weight. The weight of a solid composite tire 1 would be considerably less than the weight of a conventional tire of the same size and shape. The use of radial bulkheads 71 increases the ability of the tire 1 to support weight.
Foam
In applications that would be used in environments that would have a risk of the tire being punctured the chambers could be filed with foam. Risk of puncture would be highest in combat situations where the tire could be pierced by bullets or shrapnel. Rocky or icy terrains also pose a significant danger for puncture. Using foam would cause a slight decrease in buoyancy due to the increase in weight, but it would prevent a larger loss in buoyancy than if a puncture would occur and a chamber 75 would fill with water or sand. Using a foam filled chamber 75 would have the added benefit of maintaining a more even tire 1 balance in the event of a puncture. The filing of one chamber 75 with sand or water would cause an increase in weight in one portion of the tire 1 would cause tire 1 unbalance.
Axil Hubs and Spindles
The use of axil hubs, or spindles, for flexible tires are well know in the art. The hub assembly (not shown) that is used with rubber tires is typically of unified construction. The smaller and thinner tires can stretch to be moved over the lip of the hub. Some larger rubber tire applications use a bifurcated hub assembly (not shown) since the rubber is too thick to stretch as does the smaller thinner tires.
Due to the composite construction the instant invention will not be flexible and will typically require a bifurcated hub that would have an inner and an outer hub section (also not shown). The optimal material for a hub on a rescue vehicle would be aluminum due to weight considerations. The specific hub required will be determined by the needs of the vehicle that utilizes the instant invention and is not germane to the instant invention.
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Thread
Traction design for tires is well known in the art and the particular tread design 15 is not germane to the instant invention. However, using tires in mediums such as wet soil, sandy areas, water, or any mixture of these will require the use of treads of a particular design if the medium they are to travel on is known.
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While several embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects.