Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ANTI-PERSONNEL MINE FOOT PROTECTION SYSTEMS
BACKGROUND OF THE INVENTION
a) Field of the Invention
This invention relates to a new or improved system to provide foot
protection against anti-personnel land mines. The invention is particularly
intended
for use by military specialists involved in mine clearance operations,
although it is
likewise suitable for use by other military and civilian personnel.
b) Description of the Prior Art
For many decades the laying of mine fields has been used by various
military organizations both official and irregular to deny access or to
inhibit
movement of enemy personnel in selected locations. The mines are buried or
otherwise camouflaged and are designed to explode when actuated by the
presence of enemy personnel, being triggered by various means such as trip
wires,
pressure sensors, etc. Larger mines are deployed for the purpose of destroying
or
disabling trucks and tracked armoured vehicles, but these mines are in some
respects of lesser concern since they are not likely to be triggered by an
individual's
stepping on them.
Well organized official national armies when deploying a mine field
make a practice of preparing a map indicating the location of each mine that
is laid,
both for the safety of their own personnel, and also with a view to removing
the
mines after a conflict situation has been resolved. However other military
organizations and especially guerillas too often do not prepare proper maps of
the
location of mines that have been deployed and make no effort whatever to
retrieve
previously laid mines. Such abandoned mines therefore remain in place
constituting for many years a hazard to the lives of wild animals, livestock,
and
people residing in the vicinity. Every year thousands of people are
accidentally
killed or maimed by such abandoned anti-personnel mines, and furthermore the
presence of mines denies people access to or utilization of large tracts of
land.
The clearance of mine fields is extremely dangerous work and is dealt
with by specially trained military personnel who are skilled in de-activation
and
removal or safe detonation of mines. However no level of skill can guarantee
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against accidental detonation of an anti-persorinel mine w'~ich has not been
detected or which is of a design that is unfamiliar to the mine disposal
operative,
and accordingly it is necessary to equip the operative with as much protective
clothing as is possible without excessively restricting his freedom of
movement.
Thus it is usual to protect mine clearance operatives by providing clothing
and
padding which will absorb the blast forces and projectiles created by anti-
personnel
mines. Such equipment includes protective helmets and footwear.
Experience has shown that the feet of operatives working on mine
clearance are particularly vulnerable to injury, and various proposals have
been
brought forth to reduce such injuries. Examples of prior proposals for
protective
footwear are shown in U.S. Patents 2,720,714 Krohn et al., 3,318,024 Fujinaka
et al
and 3,516,181 Jordan.
None of the prior proposals for protective footwear has been entirely
satisfactory. Some proposals are too weighty and unwieldy while others do not
provide a sufficient spacing of the feet of the operative above the ground in
which a
mine may be embedded, and still others do not provide sufficient stability for
support of the operator. None of the prior protective footwear can avoid the
possibility that the operative may tread on and thus detonate a mine located
immediately underneath his foot.
Although U.S. 3,516,181 Jordan shows protective foot gear that is
designed to support the foot of the operative at a substantial distance above
the
ground surface, it clearly incapable of providing stable support due to the
very
narrow width of the support member 22, which is more in the form of a blade
than a
platform and thus will not provide very stable support. Furthermore, since
Jordan's
support member 22 is continuous, it will not even provide stable support in
the
longitudinal direction, e.g. if it is placed upon a small stone or the like.
Additionally,
since there is material continuously between the lower surface 23 of the
support 22
and the operative's foot, the blast force of any mine detonated by the foot
gear will
be transmitted through the foot ear upwardly to the operative's foot.
SUMMARY OF THE INVENTION
The present invention provides a protection system to protect the foot
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of a user against anti-personnel mines and the like, said system comprising: a
a a a a
frame configured to receive and be attached to a user's footwear to support
the foot
in a location that is at a height of at least about 10 cm above a ground
surface; said
frame carrying ground-engaging elements that have overall extents in
longitudinal
and lateral directions that are sufficient to provide stable support for said
frame on a
supporting ground surface; said ground-engaging elements being discrete and
spaced apart, and said frame having an underside that is spaced upwardly in
relation to said ground-engaging elements so as to have clearance above the
supporting ground surface; at least parts of said system being compliantly
deformable to accommodate irregularities in the supporting ground surface. The
system preferably also includes blast protecting material completely covering
the
underside of the foot location.
Preferably the ground-engaging elements of the system are spaced
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forwardly and rearwardly relative to the foot location so that they will not
cause
detonation of an undetected mine that is immediately below the foot of the
operative. The front ground-engaging elements are positioned between about 10
and 40 cm preferably between about 15 and 30 cm, and most preferably about 25
cm forwardly of the front of the foot location; the rear ground engaging
elements are
spaced to the rear of the foot location by similar amounts, and the front and
rear
ground-engaging elements are spaced apart longitudinally by at least about 20
cm,
preferably between about 25 and 80 cm, and most preferably about 35 cm.
The ground-engaging elements may comprise forward and rearward
pairs of laterally spaced pods which can provide a stable support for the
system
even upon irregular ground surfaces. These pods preferably have rounded
undersides to engage the ground and are carried on arms that are somewhat
resilient.
The ground-engaging elements preferably comprise resilient members
that can include chambers filled with compressible gas as in a bellows, or
foamed
plastic to permit some ground surface versatility. In some cases, rigid
contact
points may also be used, dependent on the terrain.
The blast-protecting material on the underside of the foot location
preferably has an underside that tapers convexly towards a rounded lower end
presenting a downwardly angled outer surface that will have a deflecting
effect upon
fragments which may be hurled upwardly from an exploding mine. The blast-
protecting material preferably comprises multiple layers of foam plastic or
other
energy-absorbing materials having an overall thickness in the range 3 to 15 cm
and
preferably about 10 cm, although in some embodiments the thickness may be as
little as 1 cm.
Overall it is desirable that the protection system is lightweight and not
excessively cumbersome to use. The system supports the foot of the operative
at a
height of at least 10 cm and preferably about 12 cm, in some cases to provide
enhanced protection this height may be 20 cm or more above the ground surface;
this spacing together with the forward and rearward disposition of the ground
engaging elements and the blast protecting material on the underside of the
foot
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location combine to greatly reduce the likelihood of injury to the foot in the
event
that mine detonation is occasioned by the ground engaging elements, or
otherwise
occurs in the immediate vicinity of the feet of the operative.
In terms of protection afforded to the user's foot, it is evident that the
greater the spacing vertically and horizontally between the user's foot and
the
location of an exploding mine, the less the impact of the blast effect upon
such foot.
However the cost of providing the foot protection system obviously will
increase as
its size and height increases and as the thickness of the blast protection on
the
underside of the foot location is increased, and furthermore these factors
also affect
the overall weight of the article and thus its convenience in use. If the
dimensions
of the foot protection system are too great, it becomes costly to produce and
difficult to use. Thus while a system that supports the foot 20 or more
centimeters
above the ground surface may be desirable from the safety standpoint, from the
standpoint of usability, stability and cost, it is thought that many customers
might
prefer a system providing a height in the range 10 to 12 cm, with a thickness
of
blast protecting material on the underside of the foot location of from 1 to 5
cm.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will further be described, by way of example only, with
reference to the embodiments shown in the accompanying drawings wherein:
Figure 1 is a perspective side view of a first embodiment of the foot
protection system in accordance with the invention;
Figure 2 is a perspective view of a second embodiment of the foot
protection system in accordance with the invention, shown with a boot
supported
thereon;
Figure 3 is a side elevation of the embodiment shown in Figure 2;
Figure 4A is a plan view corresponding to Figure 3;
Figure 4B is a sectional view taken on the line B-B of Figure 3;
Figure 4C is an enlarged sectional view taken on the line C-C in
Figure 4B;
Figure 5 is a perspective view of the frame portion of an alternative
embodiment of the foot protection system;
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Figure 6A is a side view of the frame portion of a third alternative
frame portion of the protection system, Figure 6B being a fragmentary view of
a foot
portion of the frame, and Figure 6C being an enlarged sectional view of a foot
portion of the frame;
Figures 7A, 7B and 7C are views corresponding to 6A, 6B and 6C
showing a fourth embodiment of the frame;
Figures 8A, 8B and 8C are views corresponding to 6A, 6B and 6C
showing a fifth embodiment;
Figure 9 is a view corresponding to Figure 5 showing a sixth
embodiment;
Figure 10 is a perspective view showing a seventh embodiment of the
foot protection system;
Figure 11 is an underneath plan view of the embodiment of Figure 10;
and
Figure 12 is a sectional view taken on the fine XII-XII of Figure 13.
Figure 13 is a longitudinal sectional view of the embodiment of Figure
10 taken on the line XIII-XIII in Figure 12; and
Figure 14 is a plan view of this embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The foot protection system shown in Figure 1 generally indicated at 10
comprises a framework 11 that is of inverted U-shape as seen in side view the
framework comprising downwardly and forwardiy curved front legs 12 and
downwardiy and rearwardly curved rear legs 13. The lower end of these legs
carry
ground-engaging elements in the form of flat pods 14, 15 respectively, which
are
upwardly curved at their forward ends and which can pivot through at least a
limited
angular range about horizontal axes to accommodate to irregularities in the
ground
surface upon which the system may be placed.
As indicated at 16, each side of the framework is telescopically
adjustable so as to selectively change the longitudinal spacing between the
front
and rear pods 14, 15 within a limited range. The outboard edges of the rear
pods
15 are somewhat flattened and for ease of use, the overall width across the
rear
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pods is less than that across the front pods by an amount of at least about 5
cm.
The framework 11 defines a foot location generally indicated at 18
which is designed to receive the foot of an operative and secure the
protection
system to the foot. In the embodiment of Figure 1 the foot location is
designed to
receive a foot that is shod in a boot or the like, but obviously could be
modified to
include built-in footwear (not shown). The framework includes a front cross
member 19 and a similar rear cross member (not shown) to provide structural
rigidity. A foot receptor sub-frame 21 is attached to the front cross member
19,
such attachment including a pivotal connection to allow the sub-frame 21 a
limited
range of pivotal movement about a generally horizontal transverse axis at its
forward end.
The foot protection system shown in Figure 1 is designed to receive
the left foot of an operative, and therefore to provide a more natural foot
attitude,
the foot receptor is toed-out by a few degrees, e.g. between 5 and 10 degrees.
The underside of the foot location is shielded from the effects of a
mine explosion by a shield 25 of lightweight blast absorbing material such as
a
lamination of med/high density and lower density polystyrene, polyethylene,
polyurethane foams, having a thickness of 5 cm to 15 cm and densities in the
range
10 to 130 kglm3. The shield 25 entirely covers the underside of the foot
location
providing continuous protection from side-to-side and from front-to-rear
beneath the
foot receptor 21. The shield has front and rear upwardly curved extensions 26,
27
which provide protection to the foot location in the case of mine detonations
that
occur to the front and to the rear thereof. Also the shield can be extended
outwardly and upwardly at the sides (not shown) of the foot location to add
further
protection.
From the foregoing description and the accompanying drawings it will
be appreciated that the foot protection system disclosed in relation to Figure
1
provides a high degree of protection to the foot of an operative. The fact
that the
front pods 14 and rear pods 15 are displaced longitudinally and do not lie
immediately beneath the foot of the user, and that the foot location is
displaced a
substantial distance ( i.e. at least 10 cm and as shown in Figure 1 20 cm)
above
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the supporting ground surface combine to greatly attenuate
the blast force upon the user's foot of a.ny mine that is
initiated through pressure exerted by the supporting pods
14, 15.
The foot protection system 10 should be as compact
and as lightweight as is consonant with safe operation by
mine clearance personnel. It should not be excessively
heavy or unwieldy since it could be worn by individuals for
shifts of several hours. Also the system 10 should
preferably not be fabricated from magnetisable material
since such could interfere with operation of metal detector
equipment that is commonly employed in mine clearance
operations. In the embodiment of Figure 1 the framework 11
is composed essentially of lightweight aluminum or aluminum
alloy tubes or composite material structures, the pods 14
and 15 being of similar material.
Referring now to Figures 2, 3 and 4, the foot
protection system 100 shown in these yews comprises a
platform 101 that is supported generally horizontally upon a
ground surface by four outwardly and downwardly curved legs
comprising two front legs 102 and two rear legs 103, each
leg carrying a ground engaging pod 104. As shown in
Figure 4A, the platform 101 has a horizontal area that can
be larger than the footprint 105 of a boot, the footprint
shown in Figure 4A representing a boot of overall length of
about 32 cm, although for convenience in use the dimensions
of the foat platform should not greatly exceed the physical
dimensions of a wearer's boot. In Fig. 4A, the platform
shown is intended to accommodate a wide range of boot sizes.
The front part of the platform 101 has fixed
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thereto a flexible sole plate 106, which is of uniform
thickness and of a width and length just smaller than the
top of the platform. The sole plate is essentially flush
with the side walls of the structure (101). The sole plate
supports the boot about 5 mm above the top of the platform
101 and extends under the sole and heel of the boot. The
sole plate 106 is attached to the platform 101 only at its
forward end by attachment means 208 and can be pivoted by
flexure about a transverse axis.
On the rear part of the sole plate 106 there is an
upstanding forwardly open U-shaped heel stopper 114 that is
formed integrally with the plate 106 and
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that has in each of its opposite sides a large rectangular recess 116 to
accommodate a corresponding hook plate 112 to delimit a range of pivotal
movement of the plate 106. Each hook plate 112 is formed integrally with a
corresponding side of the platform 101 and projects into the corresponding
rectangular recess 116, the upper end of the hook plate having a detent 107
which
projects laterally inwardly to cooperate with the upper side of the sole plate
106 to
limit the range of upwards movement of the rear part of the sole plate 106
(and with
it the heel of the boot 118) to correspond to the pivotal movement of the foot
joint of
the user as will occur in a normal walking motion. The position of the detents
107
above the platform 101 will determine the maximum range of upwards movement of
the heel. By providing for this movement the foot protection system will be
found to
be much more comfortable for use by the operator.
The sole plate 106 carries a mounting support for a binding structure
by means of which the assembly can be secured to the boot 118 of a user, the
binding comprising an adjustable instep strap 120 which spans the sides of the
sole
plate 106 across the instep portion of the boot and has ends that are
adjustably
connected by suitable fasteners (not shown) at selected locations in the sides
of the
sole plate 106 so that the binding can be adapted to accommodate boots of
various
sizes. The strap 120 is adjusted in length to snugly enclose the boot, and is
secured by suitable means such as buckles, ratchet mechanisms, or Velcro
fasteners for example. An upper binding portion comprising a U-shaped ankle
support 122 is adjustably pivotally attached at its sides to the top of the
heel
stopper 114 and also carries an adjustable strap 124 by means of which the
apparatus can be snugly secured around the boot and the lower leg of the user.
It
will be understood that the ankle support 122 is pivotal relative to the heel
stopper
114 to accommodate normal pivotal movement and adjustment of the lower leg
with
respect to the foot of the user.
The platform 101 is of overall canoe shape as is best seen in Figures
2, 3 and 4B, having a length and a width that are greater than those of any
boot
that will be accommodated, the sides of the platform tapering convexly in the
downwards direction as seen in the drawings to present a somewhat wedge-like
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aspect towards the ground, as seen particularly in Figure 4B, this being
important to
provide a deflection laterally outwardly, or forwardly or rearwardly, of the
pressure
wave loading, as well as of solid particles and fragments hurled upwardly e.g.
by
the explosion of a land mine under the foot protection system.
The internal construction of the platform is shown in Figure 4B, the
platform comprising a molded composite material shell fabricated of e.g. glass
fibre,
aramid fibre or plastic, enclosing a composite core of blast absorbing
material
comprising a lower core section 128 of low density foam plastic material and
an
upper core section 130 of a foam plastic material that is of much lower
density than
the tower section 128. Suitable materials of the core sections are:
lower section 128 polyethylene of density 65-130 kg/m3
upper section 130 polyethylene based foam 25-45 kg/m3 density
By judicious selection of the shape and material of the downwardly
facing surfaces of the platform 101 and of the nature and density of the
materials of
the core sections 128, 130, the damaging effects of blast pressure loading and
fragmentation pieces hurled upwardly by an exploding mine can be very much
diminished so that the danger of injury to the feet or lower limbs of the user
is
correspondingly reduced. Moreover, the blast wave loading on the foot itself
is
attenuated by the energy absorbing foam type materials beneath the foot
platform
and the possibility of damping of any relative motion between foot and
platform. A
single core section may be used or more than two types or densities of core
materials to attenuate the blast can be included.
The shell of the platform 101 is fabricated, e.g. by molding from a
suitable composite plastic or non-ferrous metal material, and the core
sections 128,
130 can be molded within the shell 101.
The front legs 102 and the rear legs 103 are of similar construction
each comprising an elongate curved member having an upper end that is
substantially horizontal and is attached to the underside of the platform 101,
the leg
curving away from the platform and laterally outwardly and downwardly to
terminate
in the pod 104. As seen in Figure 4C, each of the legs 102, 103 comprises a
hollow molded plastics section of somewhat triangular outline having convex
lower
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sides 132, 134 which offer a downwardly oriented wedge-like profile to
maximize
blast deflection. The pod 104 attached to the lower end of each leg 102, 103,
is of
soft construction and may be fabricated in a compressible lightweight foam
plastic
material, and has on its underside a tread rounded piece 136 having an array
of
projecting integral studs 136.1 thereon to provide improved traction between
the
pod and the ground surface. The tread piece 136 can be provided in the form of
a
hollow rounded cover fabricated e.g. in polyethylene and fixed to the
associated
stud 104 in a secure manner, yet releasable when the tread piece has to be
replaced. The rounded configuration of each tread piece 136 enables the foot
protection system to more readily adapt and find stable support upon irregular
surfaces, and this effect is enhanced by providing a measure of height
adjustability
as between the different pods 104, such height adjustability being provided
for by a
somewhat resilient construction of the legs 102, 103. The pod itself can
perform
the function of a spring or a bellows, or may serve as a rigid contact point
with the
ground.
The foot protection systems described herein counteract the effects of
exploding mines upon the feet of operatives in two ways: the configuration of
the
platform 1 and the legs 102, 103 space the user's foot, represented by the
boot
118, a substantial distance away from any mine that may be exploded by one of
the
pods 104, and the shape and construction of the legs 102, 103 and in
particular of
the lower side of the platform 101 help to deflect and/or to absorb the energy
of the
blast wave pressure and mine fragments. With reference to Figure 3, the system
supports the boot at a height H above the ground surface, and the pods 104 are
spaced apart by a distance L in the longitudinal direction. The protective
effects of
the system are enhanced with increases in both of the dimensions H and L, but
these dimensions cannot be made too large or else the system will become
unwieldy and unstable to the user. It will be understood that in mine
clearance
operations, the user will have to wear the foot protection system for many
hours,
and will also have to be able to move about in more or less unrestricted
manner
across the ground surface that is being cleared. Thus as a practical matter it
has
been determined that the dimension H should be within the range 10 to 40 cm,
and
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preferably from about 10 cm to about 20 cm, and the dimension L should be
within
the range 25 to 80 cm and preferably about 50 cm. Furthermore it is desirable
for
the pods 104 to be spaced longitudinally away from the foot location, such
spacing
being represented by the dimensions C in Figure 3, C being in the range from 0
to
25 cm, preferably between 2 and 15 cm, and most preferably about 10 cm,
dependent on the size of foot of the wearer.
As has been noted above, from the point of view of safety, it is
desirable to maximize the dimension H. However as H increases, the convenience
of use and stability of the foot protection system are reduced, and thus while
it is
preferred that H should be 20 cm or more, it is thought that practical and
useful
embodiments of the foot protection system can be provided in which H is as
little as
about 10 to 15 cm.
It will be appreciated that in terms of protective effect, the dimensions
C and H are interrelated, and for the same protective effect, if the dimension
C is
increased, then the dimension H can be reduced and vice versa. Referring to
Figure 4B, the lateral spacing between the pods 104 is represented by the
dimension D, and the overall lateral width of the system is represented by the
dimension W. These dimensions also can be varied within relatively wide
limits.
The dimension W may be anywhere within the range 10 to 40 cm, but is
preferably
about 25 cm since for widths of 30 cm or more the system becomes a little
unwieldy in requiring the user to maintain an uncomfortably large lateral
spacing
between the left foot and the right foot. The lateral extent W of the rearmost
pair of
pods 104 may be slightly less (e.g. up to 10 cm) than that between the
forwardmost
pair of pods 104, and the foot location may be correspondingly "toed-out" by
up to 5
degrees, since this makes the system more comfortable for the user in that the
user's feet can assume a more natural orientation.
The vertical thickness (T in Figure 3) of the foam filled platform 101
can likewise be varied within wide limits, and may be anywhere from 2 to 15
cm,
and preferably about 5 cm.
The combined effects of the dimensions C and H are to ensure that
there is a substantial spacing, S in Figure 3, between the pods and the
closest
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adjacent part of the foot location, since this distance S and the deflection
angle is
critical factors in reducing injuries. It has been determined that the
distance S
should be not less than 10 cm, and for practical reasons no more than 40 cm,
preferably in the range 15 to 30 cm and most preferably about 25 cm. Although
not
shown in Figure 3, it will be understood that a similar spacing S should be
provided
between the rear pods 104 and the heel of the boot of the user.
The dimensions C and S will vary somewhat according to the size of
the boot 118, and the dimensions and ranges discussed are established in
relation
to a size 12 boot (length 30 cm). The vast majority of users will have boot
sizes
less than 12, so that an additional margin of protection is available.
Alternative embodiments of the framework are shown in Figures 5
through 9. Referring to Figure 5 there is shown a framework 31 of a foot
protection
system which is equivalent in function to the framework 11 of Figure 1. For
clarity
of illustration, the foot receptor sub-frame and related parts are omitted
from these
figures. However these parts may be similar in function to those described in
relation to Figures 1 and 2 to 4.
The framework 31 is of lightweight composite construction comprising
an upper layer 32 of plastic or of composite materials (aramid, glass, carbon
or
polyethylene frbres) construction, at least one intermediate layer 33
(thickness 5
mm to 5 cm) of a rigid lightweight foam plastic material, and a lower layer 34
(thickness 5 mm to 15 mm) of blast protecting material. The composite layered
material may be fabricated in flat sections which are subsequently cut to
shape and
bent into the arched configuration as shown in Figure 5. The framework may
include an integrally molded toe cap 35. Forwardly of the toe cap the
framework
divides into two curved limbs 36 which terminate in a transverse ground-
engaging
pad assembly 37. At the rear of the framework 31 there are two laterally
spaced
downwardly curved limbs 38 which terminate in a rear ground-engaging pad
assembly 39. The pad assemblies 37, 39 have a generally rectangular footprint
extending transverse to the length of the frame, and are fabricated to be of
compliantiy compressible structure. For this purpose the pad assemblies may
constitute gas filled structures, or compressible foam.
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It will be appreciated that the limbs 36 and 38 are of resiliently flexible
composition, and this combined with the inherent compressibility of the pad
(or
foam) assemblies 37, 39 ensures that the framework 31 can readily accommodate
itself to irregularities in the ground surface upon which it is supported.
Referring to Figures 6A, 6B and 6C, the framework 41 shown here is
similar in construction and configuration to that shown in Figures 2 to 5 and
will not
be described further. In Figures 6A to 6B, the ground-engaging elements are
formed by generally rectangular feet 42, 43 which are pivotally attached to
the lower
ends of the forward and rearward limbs 44, 45 respectively by pivot pins 46,
47
respectively received in rounded end pieces 48, 49 carried at the lower ends
of the
limbs 44, 45. The feet 44, 45 have upwardly curved front ends and comprise a
thin
profiled traction pad 50a over a lightweight plastic backing piece 50b.
Referring to Figures 7A, 7B and 7C there is shown a foot protection
system framework 51 which is similar in construction and configuration to
those
discussed above in relation to Figures 5 and 6. At the lower end of each of
the
legs 52, 53 is a pad assembly in the form of a somewhat rectangular air filled
compartment 54, or readily compressible pod, e.g. of foam, attached to the
lower
end of the associated leg by an adhered backing piece 56 which is bonded to
the
top of the pod (air bag) 54 and to the corresponding leg 52, 53.
The framework 61 shown in Figure 8A is of similar shape and
construction to that shown in Figures 5, 6A and 7A, defining spaced pairs of
front
legs 62 and rear legs 63. The ground-engaging feet 64 in Figures 8A to 8C are
similar in construction to those of Figures 6A to 6C comprising traction pads
adhered to lightweight plastic backing pieces. On the upper side of each of
the feet
64 there is a tubular deformable bellows 66 forming a connection with the
lower end
of the leg 62, 63 through a suitable connecting layer 67. The backing piece of
each
foot 64 is preferably of high density foam material, the bellows being of
elastic
configuration and therefore capable of a large range of pivotal deformation
about
any horizontal axis.
The framework 71 shown in Figure 9 is generally similar in shape and
construction to the examples of Figures 5, 6A, 7A and 8A and may include any
of
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the arrangements of traction pads, air chambers, bellows and the Pike as
disclosed
therein. The Figure 9 embodiment however is further characterized by the
provision
of a rectangular platform 74 which is attached to the framework 71 and
projects
horizontally over the front and rear legs 72, 73. The platform 74 can be made
integral with the central part of the framework, and may incorporate a limited
degree
of resilience, the ends 76, 77 being spaced above the corresponding lower ends
of
the front and rear legs 72, 73. The platform thus provides added protection in
the
event that the legs 72, 73 are broken off by an exploding mine. In this event
the
front and rear platform ends 76, 77 will act to prevent broken fragments being
projected directly upwardly towards the operative, but rather will deflect
them
outwardly away from the operative. The platform, although being structurally
much
lighter than the legs is nonetheless likely to be effective for the intended
purpose by
virtue of the fact that it is of resilient construction and is at a greater
spacing above
the ground surface than are the legs. Suitable materials for the platform are
composite materials similar to those used for the shell in Figs. 2-6 (e.g.
comprised
of aramid, glass or plastic fibres).
Figures 10 to 14 illustrate a foot protection system that is somewhat
similar to that shown in Figures 2 to 4 but is designed to support the user's
foot at a
height of just over 13 cm above the supporting ground surface 80 (Fig. 12) and
to
incorporate a platform that is considerably thinner than the one shown in
Figures 2
to 4.
Referring to Figures 10 to 14 the foot protection system 81 comprises
a platform 82 on the upper side of which is a sole plate 83 similar in form to
the
sole plate 106 of Figures 2 to 4, the sole plate overlying and being
substantially co-
extensive with the platform and being connected thereto by fastening means in
the
form of plastic screws 84 located at the mid sole or forwardly so that the
rearward
part of the sole plate is free to flex and pivot upwardly about the screws 84.
As
before the sole plate 83 carries a binding structure 85 (similar to that
described in
relation to Figures 2 to 4) for securing a boot 118 therein, and may also
include a
detent structure (not shown) to limit the upwards movement of the heel portion
of
the boot and sole plate relative to the platform 82.
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As seen in Figure 12, the platform 82 is relatively thin, having overall a
general thickness of approximately 5 cm, although its protective effect is
enhanced
to some extent by the sole plate 83 which typically comprises a sheet of
polyethylene or similar flexible plastic material of thickness 2.5 to 5 mm. As
shown
in Figures 12 and 13, the lower portions 85.1 of the binding 85 can be molded
integral with the sole plate 83. The structure of the platform is most clearly
seen in
Figures 12 and 13 as comprising an outer shell or canoe 82.1 of molded plastic
material of a thickness between 8 and 10 mm surrounding a foam interior 82.2,
the
upper edge of the shell 82.1 extending slightly above the sole plate 83.
As seen in Figure 14, the overall dimensions of the platform 82 are
approximately 38 cm in length and 14.5 cm in width, the height of the upper
surface
of the sole plate above the ground surface 80 being approximately 13 cm.
The underside of the platform 82 is formed with a pair of generally V-
shaped recesses 87, 88 to receive V-shaped front and rear leg assemblies 89,
90
which are secured in position by nylon fasteners 91 which connect each to the
platform 82.
As seen in Figure 12, the undersides of the platform 82 and leg
assemblies form a downwardly projecting convex curvature 92 (Figure 12) which
is
designed to help deflect blast effects laterally.
As best seen in Figure 13, the leg assemblies 89, 90 include integral
legs 93 each terminating in a screw-threaded stud 93.1 carrying pods 94,
similar to
the legs and pods as described in relation to the embodiment of Figures 2 to
4.
The pods 94 are threadedly attached to the studs 93.1 and can therefore be
removed when required. The leg assemblies 89, 90 may be formed as hollow roto-
molded plastic components, and have upper sides molded to flt snugly within
the
recesses 87, 88 on the underside of the shell 82.1 so as to be rigidly and
securely
attached to the latter by means of the nylon fasteners 91. The studded pods 94
are
of molded polyurethane, having integrally formed attachment threading therein.
Overall, the foot protection system of Figures 10 to 14 is fabricated
substantially entirely in lightweight plastic materials to minimize the amount
of
damage caused by parts which break free during an explosion. Typically, an
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WO 99/04216 PCT/CA98/00694
undetected mine could be triggered by contact by a front one of the pods 94,
and
explosion of the mine would most probably result in destruction of that pod
and its
associated leg 93, fragments of which would be hurled upwards. However the
damage caused by such fragments is minimized because of their lightweight
construction, and in any event destruction of the foot protection system does
not
produce any sharp edged metal fragments.
Although some presently preferred exemplary embodiments are
described in the foregoing in relation to the drawings, it will be understood
that the
invention is capable of modification in its details, and therefore encompasses
all
embodiments falling within the ambit of the appended claims.
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