WO2018051054A1

WO2018051054A1 - Reduction of risk of injury from anti-personnel mines

Info

Publication number: WO2018051054A1
Application number: PCT/GB2017/000141
Authority: WO
Inventors: Colin SKELTON
Original assignee: The Secretary Of State For Defence
Priority date: 2016-09-19
Filing date: 2017-09-18
Publication date: 2018-03-22
Also published as: GB2553927B; GB201714796D0; GB201615951D0; GB2553927A

Abstract

The injuries inflicted on persons by anti-personnel mines are reduced or mitigated by using material having a density of at least 6 g/cm³ and, preferably, a density of at least 6 g/cm³ and a mass of at least 200 g, worn about the heel, ankle or lower leg of an individual. The invention also relates to the use of footwear comprising material having a density of at least 6 g/cm³ to mitigate the risk of injury, and protective footgear comprising a heel section adapted to fit around the heel of an item of footwear, and fastening means for attaching the footgear to said item of footwear, wherein the heel section itself comprises a base region formed from a material having a density of at least 6 g/cm³ and a mass of at least 200 g, and an upper region connected to the base region and supporting the fastening means.

Description

Reduction of Risk of Injury from Anti-Personnel Mines

The present invention relates generally to the reduction and prevention of injuries inflicted upon persons from stepping on explosives underfoot, such as anti-personnel mines, and more specifically to the reduction of tibial fractures and traumatic amputations of the lower limb. More particularly, the invention is concerned with the use of material having a density of at least 6 g/cm³, and the use of footwear comprising material having a density of at least 6 g/cm³, to mitigate the risk of injury, and related protective footgear. Although a number of solutions to injury from anti-personnel mines have been proposed over the years, there is still a huge risk of injury. Most combat boots still provide limited protection from blast events, often resulting in traumatic amputation, foot, ankle, fibula, and tibia fractures and soft tissue injuries. Following the initiation of an anti-personnel mine, the foot, and in a large number of cases the lower half of the contact leg, is likely to be destroyed. Traumatic amputation, tissue de- vitalisation and contamination by earth or other debris, usually extending to well above the overt limit of injury, is the normal outcome. The remainder of the body may also be affected, with the upper part of the contact leg and the perineum being particularly vulnerable.

Prior art anti-personnel mine footwear often incorporates a wedge or prism having a downward facing apex, because the wedge or prism is thought to deflect the blast from the mine. The wedge or prism may be an integral part of footwear such as a boot, or may be incorporated into protective footgear that can be attached to a boot. US 3,032,894, for example, discloses footwear having a generally wedge-shaped deflector built into or embedded into the heel and shank portions of the footwear. The deflector may be formed from stainless steel or other tough metals, and is preferably hollow with relatively thin walls. Similarly, US 8,047, 1 17 discloses a blast wave attenuator attached to a sole having a generally V-shape, which reflector is hollow and foam-filled so as to reduce weight. US 3,516,181 and GB 2191384 also disclose protective footwear incorporating wedge-shaped blast deflectors, the deflectors being built into platforms that further mitigate blast damage by providing a stand-off distance. In each case, the deflector is hollow and comprises a polymer filler material.

To mitigate the threat from anti-personnel mines, improved solutions are still needed.

One object of the present invention is to provide a means of reflecting blast forces away from a person's foot or leg to reduce the likelihood of injury, and in particular reduce the likelihood of fracture of the tibia and traumatic amputations of the lower limb.

Another object of the present invention is to provide footwear and footgear that decreases impact forces upon a person's foot, thereby limiting the forces transmitted to the soldier's foot and lower limb.

'

Thus a first aspect of the present invention provides use of material of density of at least 6 g/cm³ worn about the heel, ankle or lower leg of an individual to mitigate the risk of injury to the individual from stepping on an explosive device. Preferably, the material is worn about the heel, more preferably around or underneath the lower heel.

In a preferred embodiment, the material has a density of between about 7 and 8 g/cm³, and preferably about 7.85 g/cm³.

The Applicant has found that materials of density of at least 6 g/cm³ can reflect blast forces away from an individual's foot and decrease bending moment forces upon the foot, thus mitigating the risk of injury to the individual. By reflecting blast forces and increasing the mass of the foot/ankle area to increase the bending moment required to fracture the tibia, the invention reduces the likelihood of injury, and in particular reduces the likelihood of fracture of the tibia and traumatic amputations of the lower limb.

More specifically, as discussed in more detail below in relation to the fourth aspect, locating a material having a density of at least 6 g/cm³ and a mass of at least 200 g underneath or around the lower portion of the heel reduces the blast energy reaching the lower leg sufficiently to change the bending moment and hence, the speed and angle of deflection. This in turn significantly reduces the chances of life threatening traumatic tibial fractures. The Applicant has in particular found that mild steel, having a density of about 7.85 g/cm³, and with a mass of 250 g fixed to the heel of a boot prevented fracture of the tibia in a red deer tibia lower limb model in 80% of tests. Thus in one embodiment the density is at least 6 g/cm³ together with a mass of at least 200 g, more preferably at least 250 g, to observe a reduced likelihood of injury. The material may have a density of at least 6 g/cm³ and a mass in the range 200 g to 500 g, more preferably a mass in the range 250 to 500 g.

The material may be any material having the desired density, for example a metal or metal alloy. Steel is one particular example, which could be mild steel. In one embodiment, at least a part of the material is connected to or embedded in the heel or heel counter of an item of footwear. The material may be connected to the heel using the protective footgear described in the fourth aspect. Preferably, the material is connected to the heel such that the material lies underneath or around the lower heel. The explosive may be part of an anti-personnel mine, or an anti-personnel mine.

The present invention reduces and in some events prevents lower leg injuries, especially to the tibia of a person encountering an explosive underfoot, and especially anti-personnel mines. The present invention reduces the injuries suffered by a person by limiting the blast forces (especially the bending moment) transmitted to the individual's foot and leg, and also reflecting the blast forces away from the individual's foot and leg.

5 In a second aspect, the invention provides the use of footwear comprising material of density of at least 6 g/cm³ to mitigate the risk of injury to an individual from stepping on an explosive device.

In one embodiment, the material is situated in or around the heel or the heel counter of the 10 footwear. The material may be situated around the heel using the protective footgear described in the fourth aspect. Preferably, the material is connected to the heel such that the material lies underneath or around the lower heel.

The footwear may be a military boot or anti-personnel mine footwear.

Ί 5

In a third aspect of the invention there is provided anti-personnel mine footwear comprising material of density of at least 6 g/cm³ to mitigate the risk of injury to an individual from stepping on an explosive device. The material may be situated in or around the heel or the heel counter of the footwear. Preferably, the material is connected to the heel such that the material lies 20 underneath or around the lower heel. The material may be mild steel with a density of about 7.85 g/cm3, and a mass of about 250g.

In a fourth aspect, there is provided protective footgear for preventing blast injury comprising a heel section adapted to fit around the heel of an item of footwear, and fastening means for 25 attaching the footgear to said item of footwear, wherein the heel section itself comprises a base region formed from a material having a density of at least 6 g/cm³ and a mass of at least 200 g, and an upper region connected to the base region and supporting the fastening means. Contrary to prior art teachings, the protective footgear of the fourth aspect does not seek to attenuate blast forces using a wedge-type deflector, or even minimise device weight per se. Instead, the inventors have used a combined knowledge of both human physiology and types of blast injury to position a selected mass of material in a position that has been found to significantly reduce the likelihood of tibial fracture and hence, traumatic lower leg amputation.

Referring to EXAMPLE 1 below, it has been found that fixing a mass of about 250 g in the form of a mild steel disk to the bottom of the heel of a military boot prevents tibial fractures in 8 out of 10 test firings. This is because locating a mass of at least 200g underneath or around the lower portion of the heel reduces the blast energy reaching the lower leg sufficiently to change the angle of deflection and bending moment and hence, the type of injury. Accordingly, in the invention of the fourth aspect, protective footgear is provided which enables a mass of at least 200 g to be attached to the bottom of the heel, or around the bottom of the heel. In order to provide praetical protective footgear, the mass needs to be provided in a reasonably compact volume; accordingly, the material has a density of at least 6 g/cm³ and a mass of at least 200 g. The material may have a density of at least 6 g/cm³ and a mass in the range 200 g to 500 g, more preferably in the range 250 g to 500 g. Setting an upper mass limit may be desirable so as not unnecessarily to impair mobility. The protective footgear is effective against common anti-personnel devices, for example a landmine comprising 50 g high explosive. The protective footgear is simple, practical, quick-don and easy to use, yet highly effective in reducing traumatic tibial injuries. Moreover, any loss in mobility is offset by the protection afforded by the device. The protective footgear comprises a heel section which is adapted to fit around the heel of an item of footwear, and fastening means for attaching the footgear to said item of footwear. The purpose of the heel section is to position material having a density of at least 6 g/cm³ and a mass of at least 200 g on or around the base of the heel. The upper region is connected to the base region to secure the base region in place, and supports fastening means that secure the footgear in place.

The base region may be a metal plate having a density of at least 6 g/cm³ and a mass of at least 200 g. Preferably, the base region forms the bottom of the heel section so that, in use, the base region lies beneath or substantially beneath the heel. The base region may extend outwards so that, in use, the base region additionally extends underneath the instep and even towards the toe section of footwear. The base region is preferably formed from a metal or metal alloy. The metal alloy may be steel, for example mild steel. In one embodiment the base region is formed from mild steel with a density of about 7.85 g/cm³ and a mass of about 250 g. Steel is a preferred metal alloy because it is cheap and readily available, but other metals and metal alloys (for example titanium alloys) may be used.

The upper region is attached to the base region and is typically configured to surround, in use, at least part of the heel. The upper region may have a tapered sideways profile so that the heel section of the protective footgear accommodates the different relative heights of the instep and the rear of a boot heel (or heel of other footwear).

The upper region may be formed from any suitable material, but is preferably a metal or metal alloy. The upper region may be connected to the base region in any suitable way, for example by a weld, or by physical attachment means such as rivets. Conveniently, the base region and heel region are formed from the same material and together form an integral heel section in which case no connection means are required. The fastening means may be any suitable fastening means, for example a strap and fastener. The upper region may comprise holes, loops, projections or suchlike to which the fastening means is attached. The protective footgear may comprise additional sections or components, for example a section extending towards or covering the sole of the foot. However, in order to provide the specific protective effect of the invention, a material having a density of at least 6 g/cm³ and a mass of at least 200 g is required in the heel section of the footgear. Any feature in one aspect of the invention may be applied to any other aspects of the invention, in any appropriate combination. In particular system aspects may be applied to method aspects and vice versa. The invention extends to a system or method substantially as herein described, with reference to the accompanying drawings. The invention will now be described, purely by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows a perspective schematic view of a heel section suitable for use in protective footgear according to the fourth aspect of the invention; and

Figure 2 shows a sideways schematic view of protective footgear according to the fourth aspect in use.

T )e drawings are for illustrative purposes only and are not to scale. EXAMPLE 1

A physical model, based on the red deer tibia, has been devised to mimic the human lower leg, which has allowed an understanding of the mechanism of injury associated with an anti- personnel mine event to be elucidated and to evaluate physical countermeasures.

The red deer tibia lower limb model comprised a red deer tibia and calcaneus encased within gelatin (representing soft tissue). The tibia of the Red Deer is similar in length and cross section to that of a human. The model uses hard tissue likely to have similar properties to human bone, thus providing an expedient and advantageous model, in comparison to the use of completely synthetic materials.

This physical model of the lower limb was then placed within a standard issue military Army boot. A flat circular disk made from mild steel with a mass of about 250 g was fixed to the bottom of the heel of the military boot. The boot was then evaluated in the red deer lower limb model.

In tests, a surrogate 50 g anti-personnel mine placed under the boot/lower limb model found that tibial fractures were prevented in 8 out of 10 test firings.

This was in comparison to control tests against a surrogate 50 g anti-personnel mine placed under the heel of a lower limb model and the standard issue military Army boot, in which severe long bone tibial fracture (traumatic amputation) occurred in four out of the five control tests. EXAMPLE 2

Referring to Figure 1 , there is shown a heel section 1 suitable for use in protective footgear according to the fourth aspect of the invention. The heel section 1 comprises a base region 4 formed from a steel plate having a mass of 250 g and a density around 7.85 g/cm³, an upper region 3 formed from steel and connected to the base region, for example by welding, and loops 2 for supporting fastening means. The upper region 3 tapers from the rear to the instep.

Alternatively/the base region 4 may be connected to the upper region 3 by casting, moulding or otherwise forming the heel section 1 as an integral unit.

Figure 2 shows protective footgear according to the fourth aspect in use. The protective footgear 10 comprises heel section 1 as described with reference to Figure 1 (the heel section having base region 4 and upper region 3) and fastening means 5 in the form of one or more straps secured by Velcro, buckle(s) or similar. The fastening means 5 is attached to the loops 2 on the upper region of the heel section, and is used to secure the protective footgear 10 to the heel of a boot 11.

It will be understood that the present invention has been described above purely by way of example and modification of detail can be made within the scope of the invention. Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

Moreover, the invention has been described with specific reference to military anti-personnel mine footwear. It will be understood that this is not intended to be limiting and the invention may be used more generally, for example in the security and humanitarian fields. Additional applications of the invention will occur to the skilled person.

Claims

1. Use of material of density of at least 6 g/cm³ worn about the heel, ankle or lower leg of an individual to mitigate the risk of injury to the individual from stepping on an explosive device.

2. Use of material according to claim 1 , wherein the material has a density of between about 7 and 8 g/cm³.

3. Use of material according to claim 1 or claim 2, wherein the material comprises steel.

4. Use of material according to any one of claims 1 to 3, wherein the mass of the material is at least 200 g.

5. Use of material according to any one of claims 1 to 4, wherein the material is mild steel with a density of about 7.85 g/cm³, and a mass of about 250 g.

6. Use according to any one of claims 1 to 5, wherein the explosive device is an antipersonnel mine.

7. Use of a material according to any one of claims 1 to 6, wherein at least a part of the material is connected to or embedded in the heel or heel counter of an item of footwear.

8. Use of footwear comprising material of density of at least 6 g/cm³ to mitigate the risk of injury to an individual from stepping on an explosive device.

9. Use of footwear according to claim 8, wherein the material is situated in or around the heel or the heel counter of the footwear.

10. Use of footwear according to claim 8 or claim 9, wherein the material has a mass of at least 200 g.

11. Anti-personnel mine footwear comprising material of density of at least 6 g/cm³ to mitigate the risk of injury to an individual from stepping on an explosive device.

12. Anti-personnel mine footwear according to claim 11 , wherein the material is situated in or around the heel or the heel counter of the footwear.

13. Anti-personnel mine footwear according to claim 12, wherein the material is mild steel with a density of about 7.85 g/cm³, and a mass of about 250 g.

14. Protective footgear for preventing blast injury comprising a heel section adapted to fit around the heel of an item of footwear, and fastening means for attaching the footgear to said item of footwear, wherein the heel section itself comprises a base region formed from a material having a density of at least 6 g/cm³ and a mass of at least 200 g, and an upper region connected to the base region and supporting the fastening means.

15. Protective footgear according to claim 14, wherein the base region is formed from a metal or metal alloy.

16. Protective footgear according to claim 15, wherein the metal alloy is steel.

17. Protective footgear according to any one of claim 14 to 16, wherein the material has a density of between about 7 and 8 g/cm³.

18. Protective footgear according to any one of claims 14 to 17, wherein the material is mild steel with a density of about 7.85 g/cm³, and a mass of about 250 g.

19. Protective footgear according to any one of claims 14 to 18, wherein the base region and heel region are formed from the same material and together form an integral heel section.

20. Protective footgear according to any one of claims 14 to 19, wherein the upper region has a tapered sideways profile.

21. Protective footgear according to any one of claims 14 to 20, wherein the fastening means comprises a strap and fastener.