GB2178296A - A mine-field shoe - Google Patents

Abstract

There is provided a mine-field shoe which is an inflatable multi-compartment air cushion 2 having when inflated, at least one flexible substantially flat, ground-contacting surface, at least one rigid tread member 20 attachable to an upper surface of the air cushion, and means 26 for attaching the mine-field shoe to a boot. Each of the compartments 4 of said air cushion is adapted to communicate with at least one other compartment. The tread member 20 may be adjustable with support plates 30 between each compartment 4 and the tread member. <IMAGE>

Description

SPECIFICATION A mie4ieId shoe The present invention relates to a device for reducingthe danger of accidental detonation of a land mine and more particularIy'to a mine-field shoe.

Land mines are usually detonated when a pressure, exceeding a predetermined threshold, is applied thereon. The present sensitivity to the detonation of a mine is governed, on the one hand, by the desire to provide a mine which will explode underthe application of a minimal pressure and, on the other hand, a mine which will not be accidentally detonated by, e.g., the soil covering the same, or by passing, small animals.

Similarto the solution found and used by snow walkers' snowshoes enabling the wearers to walk on deep snow without sinking, it has been suggested to use mine-field shoes composed of a flat, rigid surface which, as it is understood, reduces the wearer's pressure on the ground per unit area. The main disadvantages, however, of such mine-field shoes are the difficulty of movement orwalking due to the rigidity ofthe ground contacting relatively large surface and, which is even more important, the fact that such shoes are effective only on a smooth ground.

This is so since once the ground is uneven or scattered with stones, stepping thereon will no longer evenly distribute the wearer's weight across the entire tread surface but ratherwill concentrate said weight on the highest and limited points of contact between the groundandtheshoes'surfaces.Hencethistypeof mine-field shoes are not sufficiently safe and of limited usefulness.

It is therefore a broad object of the present invention to ameliorate the above-described mine-field show and to provide a safer and more comfortable for walking mine-field shoe.

It is a further object to provide mine-field shoes which are easily transportable by being reducible in size and foldable.

In accordance with the present invention there is provided a mine-field shoe, comprising an inflatable multi-compartment air cushion having when inflated at least one flexible, substantially flat, ground-contact- ing surface at least one rigid tread member attachable to an upper surface of said air cushion, and means for attaching said mine-field shoe to a boot, wherein each ofthe compartment of said air cushion is adapted to communicate with at least one other compartment.

The invention will now be described in connection with certain preferred embodiments with reference to the following illustrativefigures so that it may be more fully understood.

With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principtes and conceptual aspects ofthe invention. In this regard, no attempt is made to show structural details ofthe invention in more detail than is necessaryfor a fundamental understanding ofthe invention, the description taken with thedrawings making apparentto those skilled in the art how the several forms ofthe invention may be embodied in practice.

The invention will now be described further, byway of example, with reference to the accompanying drawings, in which: Fig. lisa perspective, partly exploded view of a preferred embodiment of a m ine-field shoe according to the invention; Fig. 2 is a side view of the mine-field shoe attached to a wearer 5 boot; Fig. 3 is a top view and a cross sectional view along lines Ill-Ill, of Fig. 2; Fig. 4 is a perspective view showing the rigid tread surface ofanotherembodimentofthe invention; Fig.5isasimilarviewoftheaircushionofthis second embodiment;; Fig. 6 is a perspective view illustrating the strapping arrnngement ofthis embodiment, and Fig. 7 shows one ofthe air cells ofthis embodiment as well as the manner in which this cell is interconnected with the other cells of the air cushion.

Referring to the figures, there is illustrated a mine-field shoe of the foldable type, comprising an inflatable air cushion 2 composed of a plurality of chambers or compartments 4. When inflated, the compartments form an air cushion having upper and ground contacting surfaces which are substantially flat. The air cushion 2 may be made of an inner, inflatable, rubber, neoprene orthe like, balloon 6 and of an outer abrasion and cut resistantfabric 8.

Naturally the air cushion may otherwise be composed of an integral single layer of material which is impermeableto gas and having an outer surface which is abrasion and cut resistant. Such a iayer should be capable of limiting the extent two which the compartments are inflated and of keeping their volume substantially constant below a certain maximum. As further seen in the figures, the interiors of the compartments communicate with each other by means of tubing 10 extending along the sides ofthe compartments 4 and suitably interconnected, e.g., withthefittings 12,to each ofthe compartment's inlet orifices 14.One end of the tubing 10may be fixedly closedforexample,byfoldingthetubingedgeand clamping the same in its folded configuration as seen at 16, while the other end of the tubing is provided with a valve 18facilitating the controlled inflation and deflation ofthe air cushion by the mouth, by means of a pump or by means of gas bottle.

The mine-field shoe according to the invention further comprises a rigid tread surface 20 which, in the embodiment shown, is composed of a middle box-like portion 22 and of oppositely disposed U-shaped frame members 24 arranged to be extended from, and retracted into, said box-like portion 22 so that the overall length ofthetread surface is adjustable to correspond to the length ofthe air cushion 2. As is obvious, the function ofthe tread surface 20 isto evenly distribute the wearer's weight along the air cushion on top of each ofthe compartments 4.While the illustrated tread surface 20 is designed to facilitate compacting the mine-field shoe for carrying and transporting purposes, it should be understood that the tread surface could also be embodied by a single, rigid plate having an overall surface area substantially the same as that ofthe uppersurface ofthe air cushion. The tread surface 20 is fitted with straps 26 arranged for easy attachment to a wearer's boot 28.

Although the multi-compartment air cushion 2,the tubing 10 interconnecting the compartments and the tread surface 20 essentiallyform the mine-field shoe ofthe instant invention, it has been found advan tageous to attach to the upper majorflatsurface of each compartment, a support plate 30, thus effecting an even more uniform weight distribution along the entire surface area of the air cushion. The shown support plates 30 are fitted with slates 32 and with a plurality of straps 34 and 36 having meansforfixedly holding the tread surface 20 placed thereon. Such means may be of the easy to connect and release Velcro (R) attachments and/or a simple buckle or clamp.

In contradistinction to the prior art mine-field shoe, in operation,whenthe ground contacting surface of the air cushion presses against an uneven terrain or against a protrusion, a portion or portions of said surface move inwardly, the extent of which depends, inter alia, on the air pressure prevailing inside the compartment. Since the outer skin ofthe compartments is deformable and the interior of the compartments are in fluid communication with each other, the increased internal pressure, caused by the decrease in volume, will instantaneously be "absorbed" by all compartments, thus effectively allowing the defo rma- tion ofthe ground contacting surface so as to form a matching counterpart of the terrain.This, in turn, assuresthattheload on the shoe will, in most cases, still be evenly distributed along the entire ground contacting surface ofthe air cushion.

After use, the mine-field shoe shown in the figures can be easily deflated, the tread surface detached, the telescoping arms retracted, and finally, the fair cushion folded for convenienttransport.

A more elaborate embodiment is shown in Figs. 4to 7.

In this embodiment the tread surface has the form of a frame 40 consisting of four cross members 42,44,46 and48,and six lateral members 50,52,54,56,58 and 60. The latter are swivel-mounted and can be swung inwards, as shown for member 54 and indicated for the other members by the arrows. Articulation is provided by two double joints 62 and 64 and two cornerjoints 66,68, all provided with hinge pins 70. As will be shown further below, this articulation is essential for collapsing the mine-field shoes when not in use. Thus lateral members 54 and 52 can be swung towards cross member46; members 58 and 60 can be swung towards cross member 44; lateral members 56 and 50 swing towards cross members 48 and 42, respectively.The integrity ofthe frame 40 is maintained by locking pieces 72 and 74 into which the lateral members 50 to 60 snap with the aid of detents 76 in the locking members 72,74 and appropriately shaped recesses 78 in the free ends of the lateral members (see member 54). Also indicated in Fig. 4 are the respective positions ofthe heel support 80 and a sole support82forthe boot ofthe user. In a manner explained further below in conjunction with Fig. 6, these supports are fixedly attached to cross members 46 and 44, respectively.

The cross members 42 and 48 are advantageously made of extruded aluminum tubing which permits use ofthe convenient pop-type rivets for the permanent attachment of the joints 62 to 68 and the locking pieces 72,74, and ofthe boot supports 80,82. The lateral members 50 to 60, on the other hand are best made of aluminum diecastings. While,forthe sake of simplicity, shown as solid bars, they are advantageously provided with appropriately shaped and located recessesthatwill save material and reduce weight without impairing strength.

The air cushion 84, shown in Fig. 5, consists of five inflatable air cells 86, shown to better advantage in Fig. 7, located in pouches 88 the separate bottoms and sidewalls of which are made of a tough but very flexible material such as a nylon fabric. These pouches 88 are joined by a common top member 90 made of an equallytough, butsomewhat stiffer material such as a PVC-coated cotton fabric. For each pouch 88, the top member 90 is provided with an elongated slot 92 coverable by a flap 94 provided with a strip-like Velcro (R fastener 96, the mating part 98 of which is attached to the slightly bulding rim portion ofthe top member 90. These slots serve for introducing the air cells 86 into the pouches 88 and for access to the connectors and tubing sections interconnecting thefive air cells 86.The connectors and tube sections are seen to better advantage in Fig. 7. The last pouch 88 (at the far end) is provided with a double flap 94 and 100. The lowerflap 94 closes the slot 92 as do the otherflaps 94, exceptthatthe last tubing section 122 (thefirstone in Fig. 7), sticks outforseveral centimters beyond the flap end. This is the tubing section through which the entire air cushion is inflated. After inflation and closing of the pinch cock (not explicitly shown in the drawings), this end is folded back over the lower flap 94, and covered bytheupperflap 100.

Further seen onthetop member90 of the air cushion 84 arefourchannel-like straps 102 made of a relatively heavy nylon webbing and sewn to the top member 90 via reinforcing strips 104. It is these straps 102 that, straddling the frame cross members 42,44, 46 and 48, join the frame 40 to the aircushion 84. For better illustration, parts of the cross member44, the lateral members 50 and 52 as well as one locking piece 72 are shown in position. It should be noted that while in Fig.4the heel support 80 and the sole support82 are shown in their position relative to the cross members 44 and 46, these supports are not directly attached to their respective cross members, but are riveted to these cross members through, and tog ether with, the straps 102. This is seen to best advantage in Fig. 6.

Fig. 6 illustrates the two boot supports 80 and 82, and the manner in which the entire device is strapped to a boot. There is provided an ankle strap 106 complete with buckle 108 attached to the heel support via three auxiliary straps 110, and atone strap 112 with buckle 108, riveted to the cross member 44 together with the sole support82 and thecross member strap 102. After having been threaded through their respective buckles and pulledtight, the ends straps 106 and 112 are folded back and secured by means of patches of Velcro(R) fasteners not shown.

The sole support 82 is seen to be provided with two spikes 114 produced by bending upwards two sharp corners ofthe steel stamping from which the support is made. As the width betweenthetwo lateral guard rails ofthe sole support 82 is designed to accommodate the widest of soles, soles of boots of smaller sizes would be liable to slidetothe left and right in spite of the toe strap 112. Such wobbling, which might interfere with the controlled "landing" ofthe device with each step, is eliminated by these spikes which, slightly penetrating into the sole, provide sufficient friction to prevent sideway sliding.

Fig. 7 shows apartfrom an air cell 86 also the T-connectorsli6inthefirstfourcells,an L-connector 118 in the last cell, and four intermediate rubber tubing sections 120. The first tubing section 122 (already mentioned earlier) is provided with a schematically indicated pinch cock 124.

It should be remembered that all connectors and tubing sections are covered by the rim portion ofthe air-cushion top member 90 and its fiaps 94. Defective cells 86 can be easily replaced by disconnecting their tubing section or sections, pulling outthe defective cell 86 through theslot92 (Fig. 5) and introducing, and connecting, a new cell 86.

For collapsing, the top flap 100 is opened, the tubing section 122 unfolded and the pinch cock 124 opened.

The air is now let out, helped by pressure applied on the frame 40, advantageously by means ofthe still strapped in boot. The lateral members 50 to 60 are then all swung inward as far as theywill go, after which the entire device can be rolled up into a relatively small bundle, For assembling, one proceeds as follows: The bundle is unrolled and the air cushion 84 is inflatedthroughthe protruding tubing section 122. The pinch cock 124 is closed and tucked underthe flap 100. The folded lateral members 50to 60 are now unfolded until they snap into their respective locking pieces. The boat is strapped in, and the device is ready for use.

Itwill be evident to those skilled in the art thatthe invention is not limited to the details ofthe foregoing illustrative embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope ofthe invention being indicated by the appended claims ratherthan by the foregoing description, and all changes which come within the meaning and range of equivalency ofthe claims are therefore intended to be embraced therein.

Claims (9)

1. A mine-field shoe, comprising an inflatable multi-compartment air cushion having when inflated, at least one flexible substantially flat, ground-contacting surface, at least one rigid tread member attachable to an uppersurface of said aircushion, and means for attaching said mine-field shoe to a boot, wherein each of the compartments of said air cushion is adapted to communicate with at least one other compartment.

2. The mine-field shoe as claimed in claim 1 wherein said substantially flexible surface is constituted by an abrasion and cut resistant fabric.

3. The mine-field shoe as claimed in claim 1, wherein at least said upper surface is made of a noksretchable material.

4. The mine-field shoe as claimed in claim 1 wherein said rigid tread member comprises a pressure-distributing frame removably attachable to said upper surface of said air cushion.

5. The mine-field shoe as claimed in claim 1 wherein said rigid tread member is permcushion.

6. The mine-field shoe as claimed in claim 1 further comprising a multiplicity of individuai support plates interposed between the upper surface of said air cushion and said member.

7. The mine-field shoe as claimed in claim 4 wherein the dimensions of said pressure distributing frame are adjustable.

8. The mine-field shoe as claimed in claim 5, wherein said pressure-distributing frame is collapsible.

9. The mine-field shoe as claimed in claim 5, further comprising a boot heel support and a boot sole support attached to members of said pressuredistributing frame.