Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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KIR EXHAUST OUTSOLE FOR SAFETY FOOTWEAR
TECHNICAL FIELD
[0001] The invention relates to an air exhaust outsole
for safety footwear having a cushioning midsole with air
ventilating channels to vent the interior of the upper, and
a puncture resistant layer beneath the midsole, to provide
a puncture resistant footwear with a ventilated upper.
BACKGROUND OF THE ART
[0002] The safe use of footwear in many working
environments requires foot protection to avoid common
injuries. Protection may include: puncture protection from
sharp objects that puncture the sole of the footwear;
impact and compression resistance for the toe area;
metatarsal protection that reduces the chance of injury to
the metatarsal bones at the top of the foot; electrically
non-conductive properties which reduce hazards that may
result from static electricity buildup, or reduce the
possibility of ignition of explosives and volatile
chemicals; and reduce the electric hazard risk of stepping
on a live electrical wire.
[0003] In warehouse operations, manufacturing, heavy
industry and construction, workers are required as a
minimum to wear protective footwear and head protection,
fall protection harnesses and other safety equipment. In
general the employer provides, pays for or reimburses the
workers for the costs of safety equipment. Footwear being
personal and individually sized, is usually purchased by
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the worker and the costs are reimbursed by the employer.
Accordingly workers exercise a high degree of personal
choice over the comfort features and fashion when selecting
safety footwear.
(0004] Safety shoes and boots in particular are widely
used throughout workplaces to avoid easily preventable
common foot injuries caused by stepping on objects that can
puncture the sole of the footwear and injure the sole of
the wearer's foot. Governments have established
regulations for worker safety and footwear must comply with
standard puncture resistance test such as ASTM F241305
(American Society for Testing and Materials) and CSA Z195
(Canadian Standards Association).
[0005] Modern protective footwear uses puncture
resistant woven fiber layers bonded with rubber or resin.
Woven fabric layers use high strength fibers, such as
KevlarTM fibers, spun into thread and tightly woven to
replace metal plates that were used in the past to protect
the sole of the wearer. Resilient plastic toe caps protect
the wearer's toes.
[0006] Since footwear used in the workplace is often
worn all day everyday, and since employers usually
reimburse workers for the cost of safety footwear, comfort
is a paramount concern in addition to safety and
durability. Many safety footwear designs imitate the
appearance and comfort of athletic shoes or dress shoes to
enhance comfort as well as to comply with the wearer's
fashion choices for their work clothing.
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[0007] Many common designs for non-safety footwear and
running shoes include ventilation of the upper to enhance
wearing comfort by circulating air through the upper
portion sometimes creating air movement through a pumping
action as the wearer walks. Shoes for nurses for example
often include superior cushioning, air bags, heel springs
and ventilation for comfort due to the physical demands of
that profession. Examples of ventilated footwear are
described in US Patent 8,127,465 to Byrne et al and US
Patent 4,078,321 to Famolare.
[0008] When wearing conventional safety footwear that
include puncture protective soles, workers often experience
discomfort since the protective sole prevents the escape of
heat and moisture generated by the wearer's foot and
motion. The protective sole may also be made of materials
that conduct cold more readily than other conventional
materials of the footwear. Metal plates in particular
create discomfort since the metal readily conducts cold and
heat and therefore modern safety footwear generally uses
multiple puncture resistant woven fabric layers that reduce
thermal conduction as well as electrical conduction.
[0009] Safety footwear are worn outdoors in all weather
and are worn all day everyday in many environments, so
discomfort from heat, cold, moisture, and water penetration
is a serious concern. The protective sole in safety
footwear is conventionally located in the insole adjacent
to the wearer's sole. Discomfort arises from the use of a
puncture resistant protective layer that is relatively
stiff, impedes air circulation, impedes heat dissipation,
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and impedes moisture transfer that prevents adequate drying
of the insole adjacent the wearer's foot.
[00010] Accordingly, it is desirable to enhance the
comfort of safety footwear while retaining the puncture
protection provided by a puncture resistant layer.
[00011] Features that distinguish the present invention
from the background art will be apparent from review of the
disclosure, drawings and description of the invention
presented below.
DISCLOSURE OF THE INVENTION
[00012] The invention provides an air exhaust outsole,
for safety footwear having an upper with an air permeable
insole having a top insole surface for supporting a foot of
the wearer, the air exhaust outsole comprising: a midsole,
with a top midsole surface engaging a bottom insole surface
of the upper, the midsole including at least one
ventilation channel between a side midsole surface and the
top midsole surface; a puncture resistant layer with a top
surface bonded to a bottom midsole surface, the puncture
resistant layer comprising a puncture resistant core bonded
about at least a peripheral edge in a flexible coating; and
a tread layer with: a top surface bonded to a bottom
surface of the puncture resistant layer; and a bottom tread
surface.
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DESCRIPTION OF THE DRAWINGS
[00013] In order that the invention may be readily
understood, one embodiment of the invention is illustrated
by way of example in the accompanying drawings.
[00014] Figure 1 is an exploded perspective view of a
right foot safety boot where the upper is shown separated
from a cushion midsole, a puncture resistant layer and a
tread layer.
[00015] Figure 2 is a longitudinal sectional view, along
line 2-2 of Fig. 4A, of the air exhaust outsole including
four ventilation channels extending transversely through
the midsole, with a puncture resistant layer bonded above
to the midsole and bonded below to the bottom tread layer.
[00016] Figure 3 is a plan view of the top midsole
surface of Fig. 2.
[00017] Figures 4(A), 4(B), 4(C), 4(D) and 4(E) are
external views of a right foot example of the outsole,
respectively being: a bottom view; a lateral side view; a
medial side view; a front view; and a rear view.
[00018] Figure 5 is a transverse cross-sectional view
along line 5-5 of Figure 4(C).
[00019] Figure 6 is a transverse cross-sectional view
along line 6-6 of Figure 4(C).
[00020] Figure 7 is a transverse cross-sectional view
along line 7-7 of Figure 4(C).
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[00021] Figure 8 is a transverse cross-sectional view
along line 8-8 of Figure 4(C).
[00022] Figure 9 is a plan view of the top surface of the
puncture resistant layer of Fig. 2.
[00023] Further details of the invention and its
advantages will be apparent from the detailed description
included below.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[00024] Figure 1 shows an air exhaust outsole made of
three layered components, namely, the air ventilating
midsole 1, the puncture resistant layer 2 and the tread
layer 3. The puncture resistant layer 2 is located away
from the wearer's foot to enhance comfort since the midsole
1 can provide air ventilation and cushioning between the
foot and puncture resistant layer 2 as described in detail
below. The safety footwear includes an upper 4 with an air
permeable insole 5 having a top insole surface for
supporting a foot of the wearer.
[00025] As seen in Figures 1, 2-3, the midsole 1 has a
top midsole surface engaging the bottom insole surface 5 of
the upper 4. In the longitudinal sectional view of Fig. 2
and transverse sectional views of Figs. 6, 7 and 8 it can
be seen that the midsole 1 has four transverse ventilation
channels 6 that extend between outlet ports 7 in a side
midsole surface and inlet ports 8 in the top midsole
surface 9.
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[00026] Therefore each of the four longitudinally spaced
apart transverse ventilation channels 6 passes transversely
through the midsole 1 and includes an inlet port 8 in the
top insole surface 9 and a pair of outlet ports 7 in
opposing left and right side midsole surfaces. The inlet 8
and two outlet ports 7 of each channel 6 are in
communication via an internal transverse passage formed
within the midsole 1.
[00027] In the example shown in Figs. 2 and 3 the inlet
port 8 has a central inlet opening 10 to the internal
passage. Each inlet opening 10 is joined to at least one
adjacent inlet opening 10 with a shallow connecting groove
12 in the top insole surface 9. As seen in Fig. 3, the top
insole surface 9 can also include a branching ventilating
groove 12 in the ball area of the midsole 1.
[00028] The midsole 1 provides a cushion immediately
adjacent to the air permeable insole 5 of the upper 4. As
a result, the wearer's sole is separated from the puncture
resistant layer 2 by a ventilating and cushioning midsole 1
made of a flexible compressible material, for example
injection molded ethylene vinyl acetate (IMEVA), commonly
known as synthetic foam rubber. The wearer perceives
substantially the same foot comfort as a ventilated and
cushioned running shoe and does not perceive the discomfort
caused by conventional puncture resistant layers that are
generally positioned immediately adjacent or relatively
close to the insole 5 of the upper 4.
[00029] As seen in Figure 2, and Figs. 6-8, each
ventilation channel 6 has an internal transverse passage
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joining the inlet port 7 in the top insole surface 9 and
the pair of outlet ports 7 in opposing medial and lateral
side midsole surfaces. Since the midsole 1 is made of
flexible foam material, the top wall 14 of the internal
passage can flex toward a bottom wall 15 under the wearer's
foot pressure during walking. The top wall 14 rebounds to
an initial position when foot pressure is removed,
therefore the resilient action of the midsole 1 during
walking alternately decreases and restores the air volume
within the internal passage to circulate air within the
internal passage and ventilate the footwear.
[00030] The midsole 1 in the heel area can also include a
fluid filled bag (liquid or gas) or a compression spring
molded into the foam structure of the midsole 1 in a manner
similar to conventional running shoes. The top midsole
surface 9 may also include an air/vapour permeable and
liquid water resistant membrane such as GortexTM covering
the inlet port 8 to impede entrance of liquid water into
the upper 4 from the ventilation channels 6.
[00031] Figure 9 shows a detail plan view of the top
surface of the puncture resistant layer 2. The puncture
resistant layer 2 is located immediately above the rubber
tread layer 3 and is separated from the wearer's sole by
the cushioning and ventilating midsole 1. The puncture
resistant layer 2 has a top surface bonded to a bottom
surface of the midsole 1 and a bottom surface of the
puncture resistant layer 2 bonded to the tread layer 3
which has a textured bottom tread surface best seen in
Figure 4(C).
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[00032] As seen in Figure 9, the puncture resistant layer
2 has a puncture resistant core 16 bonded about at least a
peripheral edge in a flexible coating 17. The flexible
coating 17 in Figure 9 is shown as a clear plastic
surrounding the periphery of the woven fabric core 16. The
toe area of the coating is recessed to allow for the
fitting of a protective top cap 18 (shown in Fig. 2). The
flexible coating 17 allows the woven fabric puncture
resistant core 16 to be bonded to the flexible foam (IMEVA)
midsole 1 and also to the rubber (RB) tread layer 3. By
encasing the periphery and optionally the bottom of the
core 16 in a flexible coating 17, such as thermoplastic
urethane (TPU), the mutual bonding of the materials is
possible (IMEVA to TPU, TPU to woven fabric, and TPU to
RB).
[00033] The puncture resistant core 16 can be a puncture
resistant woven fabric composite or and a sheet metal plate
if desired. A puncture resistant woven fabric core 16 can
be assembled from multiple layers of woven fabric bonded
together with a resilient layer such as rubber or other
adhesive compatible with the threads of the woven fabric.
Use of a metal plate as a core 16 in some applications is
adequate, however a woven fabric core 16 and/or the
flexible coating 17 can be selected to be resistant to
electric conduction and thermal conduction. The puncture
resistant woven fabric core 16 can be made of threads spun
from para-aramid synthetic fiber (KevlarTM) bonded in
multiple layers of rubber as for example provided by the
Italian manufacturer Lonzi Egisto S.p.a.
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[00034] The outsole includes a tread layer 3 best seen in
Figure 4(C) that may be molded of rubber (RB) and is bonded
to the bottom surface of the puncture resistant layer 2.
The flexible coating 17 may cover the bottom surface of the
puncture resistant core 16 and can be molded to include
ridges or surface features compatible with the mold pattern
of the tread layer 3. In the example shown in Figure 4(C),
the flexible coating 17 is transparent and has ridges that
match the molded windows 19 in the opaque tread layer 3,
through which the transparent flexible coating 17 and
puncture resistant core 16 are visible. An advantage of
using a transparent flexible coating 17 is that the
puncture resistant core 16 with standard markings is
visible to confirm that the footwear is puncture resistant.
[00035] The outsole described above provides a cushioning
and ventilated midsole 1 adjacent the insole 5 and proximal
to the wearer's foot sole for enhanced comfort, air
circulation, heat dissipation and moisture venting. The
location of the puncture resistant layer 2 enables the
footwear to provide puncture resistance while avoiding
problems that arise if a puncture resistant layer 2 is
located close to the wearer's sole, namely, heat retention
and moisture retention within the upper 4.
[00036] Although the above description relates to a
specific preferred embodiment as presently contemplated by
the inventors, it will be understood that the invention in
its broad aspect includes mechanical and functional
equivalents of the elements described herein.
