Coating processes – Heat decomposition of applied coating or base material – Coating decomposed to form carbide or coating carbonized
Reexamination Certificate
2000-08-07
2002-10-08
Barr, Michael (Department: 1762)
Coating processes
Heat decomposition of applied coating or base material
Coating decomposed to form carbide or coating carbonized
C427S227000, C427S455000, C427S384000, C427S365000, C427S404000, C427S407100, C427S431000
Reexamination Certificate
active
06461673
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to footwear and in particular to a boot that is constructed to protect the foot of a wearer from serious damage resulting from the impact of a projectile and/or explosions from anti-personnel mines inadvertently detonated by the boot wearer. The present invention is also directed to a material that can be used, in one application, in the footwear described in the present application.
BACKGROUND TO THE INVENTION
Anti-personnel mines which are designed to explode as a person steps on or near the mine represent a common and serious problem for any troops deployed either on a conventional battle field or involved in guerilla warfare.
The amount of explosive present in a mine will dictate whether the mine on exploding maims or kills the person triggering the mine. For those devices designed simply to maim, protective footwear can play a role in lessening the likelihood of serious injury. Such footwear can also have a role in lessening the damage caused by the impact of projectiles such as bullets and shrapnel.
The present inventor has developed boots, and in particular boot soles, that can afford a level of protection to the foot of a person triggering an anti-personnel mine containing reasonable quantities of explosive while still providing the wearer with sufficient toe-to-heel flexion in the boot to allow activities such as running, jumping and climbing (see International Application Nos PCT/SG96/00001, PCT/SG96/00008 and PCT/SG97/00010).
The present invention is directed to a new type of boot structure that offers an improved level of protection to wearers that may inadvertently trigger an anti-personnel mine.
SUMMARY OF THE INVENTION
According to a first aspect, the present invention comprises a sole for an article of footwear, the sole including at least one corrugated layer of a substantially blast and/or fragment resistant material.
In one embodiment, the corrugated layer is only present in the heel of the sole. In another embodiment, the corrugated layer can be present in the portion of the sole extending forwardly from the heel or the fore portion. In a still further embodiment, the corrugated layer can extend across a substantial portion of or the entire sole. The corrugated layer is preferably formed in the sole such that the corrugations extend transversely to the longitudinal axis of the sole. In a further preferred embodiment, each of the corrugations are preferably at about a right angle to the longitudinal axis of the sole.
The corrugated layer can be formed in the sole with a planar layer formed from the blast and/or fragment resistant material disposed on the upper and/or lower sides of the corrugated layer. Preferably, the planar layer can be disposed on the upper and/or lower sides of the corrugated layer such that it meets the peaks of some or each of the corrugations of the corrugated layer. The planar layer on the upper and/or lower sides of the corrugated layer, can be formed integrally with the corrugated layer or brought into fixed attachment with the corrugated layer. Where a planar layer is disposed on at least one of the upper or lower sides of the corrugated layer, at least a first set of a plurality of channels are formed in the sole. The present inventor has determined that these channels are surprisingly effective in channelling blast gases, generated when a mine is triggered, laterally away from the foot of the wearer.
In one embodiment of the invention, the sole can have at least one corrugated layer in both the heel and the fore portion extending forwardly from the heel, with the respective corrugated layers in the heel and fore portions being formed from different materials.
The corrugated layer and planar layers disposed on the upper or lower sides of the corrugated layer can be formed from a metal-matrix composite material. The composite can be formed from woven or chopped graphite, a ceramic material or a combination of such materials. In a preferred embodiment, it is formed from woven graphite (ie carbon fibre) of the type 3K TOW, 380 g/m
2
, M60/T300 that has been impregnated with a polymer containing a metal powder. The polymer can comprise either a polymer solution or molten polymer, with the metal being a metal alloy. The metal alloy can constitute at least 20% w/w of the polymer. Examples of the metal powder include aluminium alloys, such as an alloy of aluminium, nickel and molybdenum.
To form the composite, the woven graphite can be passed through a drier (such as an electric furnace) and then through a bath of molten alloy which fully wets the fabric. In a preferred embodiment, the molten alloy is a molten aluminium alloy of aluminium, nickel and molybdenum. As the woven graphite passes through the molten alloy, the polymer carburises between 500° C. and 600° C. and a chemical bond is created between the graphite fibres and the metal. The metal matrix composite is then passed through a set of rollers that are capable of exerting about 35 to 40 tons of compressive force and which squeeze out all excess metal alloy from the composite. The result is a composite material impregnated with metal.
The metal powder added to the polymer impregnating the woven graphite can also include titanium and nickel alloys. In this case, up to 50% w/w of the metal powder can be added to the molten polymer. By using such metal powders, the step of passing the impregnated woven graphite through the bath of molten alloy can be discarded. Instead, the woven graphite can be simply passed through the drier and then through the rollers.
Other metals, such as titanium, beryllium and metal alloys of various types can then be applied to the material to provide excellent bonding of the material. The other metals can also be applied by processes such as plasma spraying or hot sheet pressing.
In an alternative embodiment, the corrugated layer and planar layers disposed on the upper and/or lower sides of the corrugated layer can be formed from a polymer impregnated or an epoxy resin impregnated composite.
In a preferred embodiment of the invention, the sole includes a heel plate including a first upper portion of one or more, and preferably three, layers of woven aramid fibre. The woven aramid layers can each be formed from 280 g/m
2
woven aramid. During the manufacturing process for the sole, the layers of woven aramid fibre are preferably held together by a porous coat of adhesive, such as hot melt polyurethane adhesive. In the heel plate, the corrugated layer preferably does not extend outwardly to the periphery of the first upper portion of one or more layers of woven aramid fibre. Rather, it preferably extends to a position inwardly from the periphery with the distance or gap between the periphery of the inner portion and the corrugated layer being substantially identical about the periphery of the heel plate. In one particularly preferred embodiment, the distance between the periphery of the first upper portion and the periphery of the corrugated layer is about 7 mm. As an example only, the material forming the corrugated layer in the heel portion can have a thickness of about 0.38 mm, with the corrugations having a height of about 4.5 mm and a peak to peak spacing of about 2 mm.
In a further embodiment, the sole includes a flexible fore plate disposed in the fore portion of the sole. The fore plate preferably includes a first upper portion of one or more, and preferably three, layers of woven aramid fibre. Again, the woven aramid layers can each be formed from 280 g/m
2
woven aramid. During the manufacturing process for the sole, the layers of woven aramid in the first upper portion of the fore plate are also preferably held together by a porous coat of adhesive, such as hot melt polyurethane adhesive.
In the case of the fore plate, the corrugated layer is preferably positioned in the fore plate immediately below the first upper portion and comprises a layer of corrugated polymer impregnated composite. The corrugated layer preferably does not extend to the periphery of the first upper portion of one or mo
Barr Michael
BFR Holdings Limited
Ladas & Parry
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