Abstrict A ballistic body armor and dehumidification system includes a flexible
carrier containing a watertight sealed pouch which itself contains
a desiccant and a stack of substantially vertical layers of ballistic
material whose performance degrades under certain conditions in
the presence of moisture. The watertight sealed pouch is mounted
into the carrier so as to cover a portion of a user's body. The
desiccant is mounted into the pouch so that either it is, or its
effect is, distributed uniformly across the ballistic material to
uniformly reduce the humidity level within the pouch.
Claims What is claimed is:
1. Ballistic body armor comprising a flexible carrier for wearing
by a user, a watertight sealed pouch mounted into said carrier so
as to cover a portion of the user's body, a compacted stack of substantially
vertical layers of flexible woven ballistic material mounted into
said pouch, a desiccant mounted into said pouch wherein said desiccant
reduces a humidity level within said pouch and said compacted stack,
wherein said desiccant is at least one desiccant impregnated sheet.
2. The ballistic body armor of claim 1 wherein said ballistic material
is PBO.
3. The ballistic body armor of claim 1 wherein said ballistic material
is PBO.
4. The ballistic body armor of claim 2 wherein said desiccant is
at least one desiccant impregnated sheet.
5. The ballistic body armor of claim 1 wherein said sheet is interleaved
between layers of said stack.
6. The ballistic body armor of claim 4 wherein said sheet is interleaved
between layers of said stack.
7. The ballistic body armor of claim 1 wherein said sheet is sandwiched
between said stack and a wall of said pouch.
8. The ballistic body armor of claim 1 wherein said desiccant is
a plurality of sheets impregnated with a desiccant means, and wherein
said plurality of sheets are interleaved with or snugly adjacent
to said stack.
9. The ballistic body armor of claim 1 wherein said plurality of
sheets are co-extensive with said layers in said stack.
10. Ballistic body armor system for reducing humidity in sealed
flexible body armor comprising a flexible carrier for wearing by
a user, a watertight sealed pouch mountable into said carrier so
as to cover a portion of the user's body, a stack of substantially
vertical layers of flexible woven ballistic material mountable into
said pouch, a desiccant mountable into said pouch distributed uniformly
across said stack, wherein said desiccant reduces a humidity level
within said pouch and said stack, wherein said desiccant is at least
one desiccant impregnated sheet.
11. The ballistic body armor of claim 10 wherein said ballistic
material is PBO.
12. The ballistic body armor of claim 11 wherein said ballistic
material is PBO.
13. The ballistic body armor of claim 11 wherein said desiccant
is at least one desiccant impregnated sheet.
14. The ballistic body armor of claim 11 wherein said sheet when
mounted in said stack is interleaved between layers of said stack
so as to be co-extensive with said layers in said pouch.
15. The ballistic body armor of claim 13 wherein said sheet is
interleaved between layers of said stack so as to be co-extensive
with said layers in said pouch.
16. The ballistic body armor of claim 11 wherein said sheet when
mounted in said pouch is sandwiched between said stack and a wall
of said pouch and is co-extensive with an outermost layer of said
stack.
17. The ballistic body armor of claim 10 wherein said desiccant
is a plurality of sheets impregnated with a desiccant means, and
wherein said plurality of sheets when mounted in said pouch are
interleaved with or snugly adjacent to said stack.
18. The ballistic body armor of claim 10 wherein said plurality
of sheets when mounted in said pouch are co-extensive with said
layers in said stack.
Description BACKGROUND OF INVENTION
This invention relates to the field of body armor and in particular
to the use of a desiccant in combination with the ballistic material
of body armor in order to maintain humidity in the body armor beneath
performance reducing levels.
P-phenylene-26-benzobisoxazole, referred to herein and by one
manufacturer, Toyobo Co., Ltd. of Osaka, Japan, by the acronym PBO
and sold by that manufacturer under the trademark Zylon, is advertised
as a rigid-rod lyotropic liquid crystal polymer having tensile strength
and modulus superior to P-Aramid fibres, and as exhibiting outstanding
high flame resistance and thermal stability among organic fibres.
In applicant's experience, use of Zylon.TM. in ballistic body armor
may provide up to approximately thirty percent better performance
as compared to, for example, older aramid ballistic materials. Zylon.TM.
is thus now a commonly used ballistic material in body armor design
because of its improved performance to protect against penetration
by ballistic projectiles such as bullets. However, it is now been
identified that Zylon.TM. degrades under combined high heat and
high humidity conditions so as to adversely affect its ballistic
performance. The degradation is not, as far as applicant is aware,
the impermanent performance degradation such as has been previously
identified due to moisture in the use Kevlar.TM. woven aramid fibre
cloth, but rather results in permanent degradation of the ballistic
material performance. In applicant's experience, and in applicant's
prior art designs such as sold by Pacific Safety Products of Kelowna,
British Columbia, Canada, applicant and other designers of ballistic
armor take extreme care in the design of, and rigorously test, any
changes to the order, number and composition of the layers of material
found with ballistic body armor. A user's life may depend on it.
Consequently, the introduction by a person skilled in the art of
flexible ballistic body armor of a substance or layer into the ballistic
material layers which is foreign to conventional substances or layers
conventionally found in ballistic body armor is in applicant's experience
rarely done. Changes and modifications are only very conservatively
implemented to avoid chances of unforeseen adverse consequences
to the ballistic performance of the layers of ballistic material
whether they be woven aramid fibre layers or the PBO layers which
are the subject of the present invention. Applicant's invention
is thus unconventional in that at least one layer of a foreign desiccant
substance, for example at least one layer of desiccant sheet is
interleaved, sandwiching, or sandwiched between the layers of conventional
PBO ballistic material in flexible ballistic body armor. It is an
object of the present invention to introduce a desiccant into ballistic
body armor employing PBO fibre ballistic body armor so as to inhibit
permanent performance degradation of the material's ballistic penetration
resistance due to moisture within the body armor. In the prior art,
applicant is aware of patents disclosing the use of moisture control
materials in protective clothing for the purposes of the comfort
of the wearer. In particular, applicant is aware of patents which
disclose the use of wicking and other materials to transfer, evaporate
or absorb moisture within the garment, as for example found disclosed
in U.S. Pat. No. 6044498 which issued to Schumann et al. on Apr.
4 2000 for Slash and Cut Resistant Garments for Protecting a Person
From Injury, U.S. Pat. No. 5471906 which issued Bachner, Jr. et
al. on Dec. 5 1995 for a Body Armor Cover and Method for Making
the Same, U.S. Pat. No. 5327811 which issued to Price et al. on
Jul. 12 1994 for a Lightweight Ballistic Protective Device, U.S.
Pat. No. 5472769 which issued to Goerz, Jr. et al. on Dec. 5
1995 for a Soft Body Armor Material with Enhanced Puncture Resistance
Comprising at Least One Continuous Fabric Having Knit Portions and
Integrally Woven Hinge Portions, U.S. Pat. No. 6233737 which issued
to Ditchfield et al. on May 22 2001 for a Concealable Ballistic
Vest and U.S. Pat. No. 6138277 which issued to Gillen et al. on
Oct. 31 2000 for a Protective Body Vest. The moisture control in
this prior art generally involves the use of fabric layers for example
the moisture absorbing inner layer of Goerz, Jr., or the vapour
permeable cover layer over the flexible armor plating layer of Bachner,
Jr. et al. Similarly, in the prior art applicant is also aware of
a Korean Patent, Patent No. KR 2001017116 which issued to Lee for
a Bulletproof Vest Having Air Ventilation Property and which discloses
the use within a bulletproof vest of inner covers of foamed polyethylene
material providing such an air ventilation property so that sweat
moisture is transferred from the body of the user to a moisture
absorbing fibre positioned inside an outer cover.
SUMMARY OF INVENTION
The present invention is ballistic body armor wherein sheets of
ballistic material such as PBO are contained in a layered stack
within a sealed watertight pouch mounted or mountable into a flexible
carrier for wear by a user. The pouch is sealed so that whatever
ambient humidity is introduced into the pouch during manufacturing
remains the maximum ambient humidity. A desiccant and desiccant
storage means, for example desiccant impregnated sheets of paper,
are contained within the pouch. The desiccant sheets may form inter-leaved
layers within the stack of layers of ballistic material or may sandwich
the stack, or may be a single sheet which may be sandwiched within
the stack or otherwise inserted anywhere into the pouch. The desiccant
removes or reduces humidity levels within the pouch to such low
levels as to remain below humidity levels which, in combination
with high heat, would permanently degrade the performance of PBO
fibres making up the layers of ballistic material.
It is intended to be within the scope of the present invention
to introduce desiccant by a storage and delivery means, such as
a matrix or sheet impregnated with a desiccant chemical composition,
into a sealed pouch containing layers of ballistic material such
as PBO whose ballistic performance degrades due to high humidity
so as to inhibit high humidity induced ballistic performance degradation
of the ballistic material within the pouch. The pouch is for mounting
into ballistic body armor.
In summary then, the ballistic body armor and dehumidification
system according to the present invention includes a flexible carrier
for wearing by a user. The carrier contains a watertight sealed
pouch. The pouch contains a stack of layers of ballistic material,
such as PBO, whose performance degrades under certain conditions
in the presence of moisture, and a desiccant. The watertight sealed
pouch is mounted into the carrier so as to cover a portion of the
user's body when the user is wearing the body armor. When the armor
is worn by the user, the stack is a stack of substantially vertical
layers of flexible ballistic material mounted into the pouch. The
desiccant is mounted into the pouch. Because of the wicking effect
or aerating effect of the porous weave of the ballistic material,
the desiccant may be placed anywhere within the pouch and its effect
is distributed uniformly across the stack, to uniformly reduce a
humidity level within the pouch and the stack. The desiccant and
the nature of woven ballistic material cooperate so that a small
amount, such as a small sheet of a desiccant impregnated flexible
matrix simply placed anywhere in the pouch will have a far-reaching
dehumidification effect on the conventionally closely compacted
stack of layers of ballistic material. The desiccant sheet may be
interleaved between layers of the stack or may be partially co-extensive
with the layers in the pouch, and/or sandwiched between the stack
and a wall of the pouch and may be partially co-extensive with an
outermost layer of the stack. The desiccant may be a matrix other
than a sheet or may be a plurality of carrier sheets impregnated
with a desiccant means such as a desiccant chemical composition,
wherein the plurality of sheets are interleaved with or snugly adjacent
to the stack, again, for example, at least partially co-extensive
with the layers in the stack.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is, in elevation view, the front and back panel of one form
of body armor incorporating the present invention laid flat, the
armor casing partially cut away.
FIG. 2 is, in partially cut away elevation view, a water impervious
pouch containing sheets of ballistic material and desiccant for
mounting into the body armor of FIG. 1.
FIG. 3 is a sectional view along line 3--3 in FIG. 2.
DETAILED DESCRIPTION
With reference to the drawings, wherein similar characters of reference
denote corresponding parts in each view, as seen in FIGS. 1-3 ballistic
body armor 10 may include front and back panels 12 and 14 respectively.
Each of the panels may have an outer fabric casing or carrier 16
for example sewn around the panel's circumferential edges so as
to define in combination with the assembled front and back panels,
side arm openings and an upper neck opening for the user. Within
each of the panels, and retained snugly and conformally so as to
correspond to the profiled outline of each panel, is a sealed water
impermeable pouch 18 for example, a heat sealed plastic pouch.
Each pouch is sealed contiguously around its perimeter so as to
define a cavity 20 within the pouch. The cavity is generally planar
when the pouch is laid flat. A stack of adjacently layered generally
parallel sheets of Zylon.TM. PBO fibre material 22 are snugly mounted
within pouch 18 so as to maintain sheets 22 generally parallel and
compactly sandwiched between front and back faces 18a and 18b respectively
of pouch 18.
Pouch 18 contains at least one flexible sheet 24 impregnated with
a desiccant such as Drikette Desiccant Paper, sold by S & D
Chemical of Scarborough, Ontario, Canada, and manufactured by Multisorb
Technologies Inc. of Buffalo, N.Y., United States. Such desiccant
paper may absorb up to three hundred times its weight in moisture.
Sheets 24 may be desiccant impregnated paper sheets, but it is not
intended to be limiting as many desiccant storage and delivery means
would work to introduce the desiccant and uniformly dehumidify a
stack of sheets 22 within sealed pouch 18 so as to reduce humidity
levels within the pouch. The use of desiccant sheets may provide
the advantage of a consistent, structurally stable and uniform distribution
of the desiccant across, that is parallel to, at least a portion
of the surface area of the pouch which would be exposed to penetration
by ballistic projectiles. Uniform distribution of the effect of
the desiccant, which remains constantly uniform in cooperation with
the wicking or porous nature of the weave of woven ballistic material
such as PBO ballistic material offers the advantage of uniform humidity
control across the pouch no matter where the desiccant is mounted,
so long as exposed to the ballistic material in the pouch, which
may be relied on for the operative life of the armor, minimizing
the risk of isolated areas of higher humidity within the distributed
volume of the cavity within the pouch.
As will be apparent to those skilled in the art in the light of
the foregoing disclosure, many alterations and modificaare possible
in the practice of this invention without departing from the spirit
or scope thereof. Accordingly, the scope of the invention is to
be construed in accordance with the substance defined by the following
claims. |