Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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~/0 91/1 1928 PCr/US9~/OU~90
ARTICLE OF FOOl~WEAR HAVI~G IMPROVED MIDSOLE
BACKGROUND OF THE INVENTION
1. Fi~ld o~f the Invention
The present invention relates to improved article~ of
footwear, particularly shoes having improved step cu~hioning and
ventilation of the foot of the wearer. More particularly ~till,
it relates to improvements in midsoles.
2. Backaround Art
A large number of sport shoes such aq running shoes have
been disclo~ed in the art and many are on the market, displaying
variouR forms of midsole for the purpose of improving the
performance of athletic shoes. Many ~haped outsoles, which are
the only portions which actually contact the ground, have been
proposed to provide shock ab~orption features.
Many items of prior art are known, such as U.S. Patent No.
4,782,603 issued November 8, 1988 to S.C. Brown. This patent
provides a separate molded mid~ole encap~ulating a ~eries of
parallel, spaced-apart tube~, disposed in a generally transverse
po~i~ion with regard to the length of a shoe. The parallel tubes
are subject to compres~ion with the step of the wearer, and the
patent states that the tubes must be of suficient re~iliency and
strength to resi3t collap~e along their walls.
U.S. Patent No. 49316,332 is~ued February 23, 1982, to Giese
et al shows an outsole with hollow portion~ adapted to retain a
shock absorbing materlal, and surrounded by a comparatively hard
rim portions of the outsole.
U.S. Patent No. 4,608,768 i~ u~d September 2, 1986, to
Cavanagh discloses the u~e of plug~ which are in~erted in an
openwork ~upport forming a mid~ole. The plugs are made of a
material ~hat i8 harder than that of the mid~ole.
U.S. Patent No. 4,831,749 is~ued May 23, 1989, to T~ai
disclo~e~ a footwear including a ventilating and ma~saging insole
having a plurality of uppar beads protruding upwardly to touch ~ -
a wearer'~ ~oot and a plurality of lower bead~ protruding
downwardly to ride on a footwear sole ~o that upon a depre~sion
of a wearer's foot on the in~ole, an air flow will be pumped
through holes each hole formed between each upper bead and each
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WO~1/1192g 207~ 33 PC'r/~1991/00590
lower bqad for ventilating the wearer ~ foot and for massaging
the 8 ame .
U.S. Patent No. 4,685,224 is~ued Augu~t 11, 1987, to Anger
di~clo~e~ the use of a labyrinth of ventilation channel~ between
the top-sole of a ~hoe and the under~ide of the foot. This i8
intended to provide a pumping effect to move air around and
ventilate the foot of the wearer.
U.S. Patent 3,418,731 issued December 31, 1968, to Anciaux
discloses the use of an insole for a shoe provided with upper and
lower surface~ of resilient material, and the upper surface of
the sole being provided with a plurality of blind reces~es, and
the bottom surace being provided with corresponding projections
so as to provide some ventilation during the action of walking.
The apparently closest background art encountered in the
preparatory ~earch is U.S. Patent 4,845,863 i~Yued July 11, 1989,
to Lin Yung-Mao which disclose~ the uae of an insole or mid~ole
in an active wear shoe. The specification deal~ with an
impermeable midsole/insole con~truction with downwardly
projecting resilient member~, with those members being so placed
and sized a~ to fit into receptables in the outsole to cuqhion
the step of a wearer. The patent desc~ibes prior art
deficiencies a follows:
Thus, conventional mid~ole~ do not offer anything
in the way of independent ~u~pen~ion or deformation of
various areas thereof, and further are ~uited to only
a particular wei~ht class or cushionability preference
of wearers.
The need for a midsole having a plurality of
cu~hioning elements, each demon~trating an individual
suspen~ion and deforming independently from the
remaining elements has generally been met by the
custom mid~ole aB di~closed in U.S. Patent No.
4,733,483, March 29, 1988, to Lin. However, it ha~
been found that a flat out~ol~ and mid~ole as
di~closed therein have a tendency to creata a
springboard effect which cau3es the heel to bounce and
vibrate. Unle~s the midsole fits perfectly into the
~091/ll92X 2 ~ 7 ~ ~ ~ 9 PCT/us91/no5~)
cavity created within the shoe, there i~ also a
tendency for the midsole to ~lip therein. Thus, a
need has arisen for a midsole that has a plurality of
cu~hioning elements with individual suspension that
doe~ not 91ip or vibrate.
Related U.S. Patent 4,843~741 issued July 4, 1989, also to
Lin Yung-Mao, disclose~ similar structures, but additionally the
downwardly depending plugs are provided with generally
cylindrical cavitie3 in each element, for the purpo~e of
reducing the waight of the midsole.
For further background material, the reader i~ directed to
an article in New Sci~ntist of 15 July, 1989, by Alison Turnball
"A Race for a Better Ru~ning Shoe", pages 42-44, and the
immediately following article "How Elastic i~ a Running Shoe?"
by Alexander an~ Bennett, pagas 45 and 46. The authors
discu2~ed a recent trend in athletic ~hoe manufacture which aims
to return to the runners some of the energy expended in taking
each step. Many di~closure~ in the prior art are directed at
means for achieving some return of energy in this fashion.
Alexander and Bennett s~m up their test results as follows:
The quality to look for in a shoe g heel is
probably high complianc~ (or peak deformation), which -
will reduce the forces of impact. Looking at the same
thing in a different way, ~he hsel ~hould be able to
abs~rb the foot ~ kinetic ~nergy without developing ~ -
large forces, 80 large value3 in "peak deformation" :. --
and "work of deformation" are probably good.
High energy return in the ~or~part of the ~ole
doe~ seem po~entially important (~e~ Table 3). But
the figures ~rom our te~t~ ~or the percentage of
energy returned still do not tell U9 how much energy
a shoe returns. For that, we need to know how much
energy wa ~tored in the fir~t place. The higher the
compliance (or peak deformation) and the work of
deformation, the more energy the ~ole stores as it is
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WVg~ 928 2 ~ ~J 9 ~J J PC~/I,SlJ1/~59~)
compres~ed. The higher the energy return, the more of
that energy i~ recovered in the elastic recoil.
SUMMARY OF THE INVENTION
The pre~ent invention i8 not directed to an objective of
maximizing, or even obtaining, energy return to the walkers, but
to the objective of shock-absorbing relatively gentle shock~ of
the steps of a normal walker and simultaneously ventilating the
inside of the shoes worn~
In order to achieve thi~ objective, it wa~ found that an
extremely soft material mu~t be used for the pluy~ or col~lmn~ of
the pre~ent invention and that ~uch plug~ or columns must either
point upwardly underneath a permaable and flexible top sole
(sometimes called insole and socksole) or point downwardly from
such top-~ole, and ju~t a~ importantly that ~uch columns bulge
significantly when compressed by the stepping action of a normal
walker. The bulging action moves the air between the columns,
thus ventilating the article of footwear and the foot through
the to~-sole. The softnes~ of column material en~ures a large
value in "peak deformation" for a small value in "work of
deformation."
It has been found, that ~uch footwear is beneficial to the
walker s joints and spinal column, in addition, of cour~e, to
the wearer' 8 feet.
The pre~ent invention provides an article of footwear which
includes in the ~ole area a number of vertical plug or columns
adapted to ea~ily compres~ and bulge with ea h ~tep of the
wearer. Thi8 provide~ a ~hock-absorbing element of special
value as it provides a comfortable ba~e for the foot, fairly
conformable to it8 801e contourY, and cushion~ each step of the
wearer. The compre~sibility of the thermopla~tic material i~
such that the plug~ are compre~sed and ~ignificantly deformed to
cu~hion each step of the wear2r, the deformation being
accompanied by substantial bulging of the plugs, and the
compres~io~, bulging9 and ~ub~equent recovery of the shape of
the plug~ providing ~ignificant flow of air in the sole region,
for ventilatin7 the article of footwear.
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'091/1]928 ~ ~ 7 ~ .~ 8 9 PCT/~S91/0~;90
On~ embodiment of the pre~ent invention provides a midsole
or part mid~ole adapted for inclusion in an article of footwear,
to provide atep cushioning and ventilation for the wearer. The
midsole or part midsole comprises a web portion adapted to
extend along at least a portion of an out~ole of the footwear
and includes a cuqhioning element compri~ing a plurality of
plug~ projecting perpendicularly with respect to the plane of
the web. Each plug is made of elastic but easily compressible
thermoplastic rubber or the like. The plugs are diqtributed on
a web B0 aq to provide a comfortable ba~e ~or the foot of a
wearer to cushion each step of the wearer. The distribution,
size and number of the plug~, and the compres~ibility of the
material iB such that the plugs are easily deformed and
significantly compres~ed to cu~hion each step of the wearer, the
compression being accompanied by sub3tantial bulging of the
plug. The compression, bulging, and subsequ~nt recovery of the
shape of the plug provides movement of the surrounding air, for
ventilation of the article of footwear.
In another embodiment, the invention provide~ an article of
footwear compri~ing an out~ole and an upper, the outsole being
provided with a plurality of upstanding plugs formed of
resilient easily compressible material. The plugs are
distributed on the outsole 80 as to provide a comfortable base
for the foot of a wearer, and to cu~hlon the ~teps of a wearer.
Tha distribution, size and n~mber of said plug~ and the
compres~ibility of th~ plastic ~s auch that the plugs are
deformed and aignificantly compras~ed to ~ushion each s~ep of
the wearor, the compres3ion being accompanied by sub~tantial
bulging o~ the plug. The compression, bulging, and ~ubsequent
recovery of the shape of the plug providing a ~ignificant flow
of air along the outsole, for ventilation of the article of
footwear.
BRIEF DESCRIPTION OF TEE DRAWINGS
The preferred embodiment~ of the pre~ent invention will now
be described in detail in conjunction with the annexed drawings,
in which:
WO91/1192~ 2 0 7 3 ~fl PCT/~S91/005g~
FigurQ 1 show~ a plan view of a midsole manufactured in
accordance with a preferr~d embodiment of this invention;
Eigure 2 show~ a perspective view of a portion of a web
shown in Figure l;
Figures 3, 4, and 5 are side elevation~ of a portion of web
as ~hown in Figure 2, illustrating three embodiments of the
upstanding plugs of the invention;
Figure 6 hows a different embodiment of a web, provided
with a sock-sole;
Figure 7 shows a cut-away view of a complete shoe embodying
one aspect of this invention;
Figure 8 shows a further embodiment of the inventive
concept employing the compressible plugs;
Figure 9 shows an out301e provided with cavitie~ or ~paces
for in~tallation of partial midsole 8eCtions of the type shown
in Figure 2;
Figure~ 10 and 11 ~how ections of web 3uch as shown in
Figure 2, with variationa in the shape of the plugs;
Figure 12 ~how~ a toe portion 41 of a web a3 shown in
Figure 9, ln which the forwar~most plugs 53 are ~omewhat
progressively shorter in length to ~uit a spacific installation;
Figure 13 show~ a variation of the invention;
Figure 14 shows a partial midsole conRtruction in the heel
of a shoe according to the present invention; and
Figure 15 show~ a variation of the present invention as
applied to the heel of a women'~ shoe or sandal.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With referenc~ to Figure 1 of the drawingY, it ~ho~s a plan
view of a mid~ole shown generally a~ web 10 which i8 provided
with a large number of upstanding plug~ 11. The~e plugs are
dispo~ed in thi~ embodiment along the entire midsole 10, which
extends from the toe portion 12 through the ball portion 13 to
t~e heel portion 14. In thi embodiment each plug 11 is
up~tanding with respect to the web 10, and i9 affixed to the web
at its proximal end. Each plug 11 in thi~ embodiment di~plays
a central aperture 16.
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09l/11928 ~ ~ 7 ~ PCT/US~l/00~90
The entire midsole 10 i8 preferably manufactur~d by
injection moldins, in which case the web 10 of the midsole a~
well as ~he pLugs 11 are of the same material, and in which case
the web 10 is highly flexible but not air-permeable. Such
midsole then would be suitable for inclusion in an article of
footwear, where the web 10 i~ in contact with the top of the
out~ole and the plugs 11 pro~ect upwardly.
The most ~uitable material found for such mid~ole is that
known a~ "Super~oft" thermopla~tic resin available from GLS
PLASTICS of Woodstock, IL 60098, U.S.A. ~sold by them under item
#G3294). The material is made from a thermoplastic compound
known as "Kraton"~ supplied by the Shell Chemical Company. The
preferred Kraton compound3 ~because they are softest having
Shore A hardnes~ [D-2240] o~ 27 and 34~ are Kraton D-2104 and
Kraton D~3226.
The re ulting Supersoft thermopla~tic yield~ a midsole
material having Durometer readings ~elow 30, and preferably in
the vicinity of 20. In spite of the softnes3 of the resultant
midsole, it still exhibits excellent elasticity and long life.
Of cour~e, there are o~her material3 besides Kraton, such as
Estane, polyvinyl chloride or rubber. The requi~ite
characteri3tics of ~he material is that they yield plugs 11 that
are ea ily compressible and significantly ~eformable ~generally
having Durometer reading~ below appr. 30) but that have long
life and good ela~ticity in order to spring back to their
original ~hape onca compres~ive forces have been re~oved. The
~hape of the plug3 11 is not critical, and whether they are
hollow or solid does not generally affect their deormability.
In the embodiment of Figure 1 they are made hollow in order to
save thermoplaatic re in.
Turning now to Figures 2 and 3, these show portions of the
midsole shown in Figure 1 in perspective view and s~de elevation
r~pectively. In Figure 3 it can be seen that thi~ embodiment
i~ provided with lower projection~ 20, which provide a small
amount of ventila~ion below the midsole. In Figure 4 the plugs
are shown as item~ 20 and 21. It will be ~e~n that in the
embodiments shown in Eigure 4, the plug~ are of varying
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WO ~1/11928 ~ ~3 7 ~ 3 ~ ~ Pcr/ussl/oo~so
thi~kne~ (i e., height). Such thickness or height i~ of course
diqcretionary, but values below 10 mm would appear reason~ble.
In Figure 5 it will be seen that the plugq 22 are held in
place in the mid~qole by a web 10 which i9 centrally located with
respect to the plugs 22. This, of course, adds to
cushionability of shocks.
In Figures 3, 4 and 5, the central aperture-q 16 are Rhown
in plugs 11, 20, 21, and 22 aR dotted lines.
Figure 6 shows an embodiment in which a portion of midsole
as shown in Figure 3 is provided with a top web 25, which
suitably can be prepared of porous material, or it can be a
perforated material, thereby providing for Rome movement of air.
In thi~ figure, the plugR 11 are ~hown compressively deformed
and bulging.
Figure 7 ~hows a cut-away view of a shoe embodying on~ form
of the present invention, in which the midsole shown in Figure
1 is in place on top of outsole 31 in a shoe. A flexible, air-
permeable top-sole 30 i~ in place over the midsole.
Figure 2 ~hows a variation whersin the outsole 31 in the
embodiment shown in Figure 7 i8 replaced by outsole 32, which i8
provided with a multipli~ity of pockets 33 adapted to receive
and retain plugs 11 of the type discu~ed above, thus
eliminating ~he need ~or the web 10 to retain these plug~ in
place. Plugs 11 may be retained permanently in hole~ 33 by
adheRion means, or any other suitable means.
Figure 9 show~ an embodiment wherein an out~ole 42 i8
provided during manufacture with cut-away portion~ 43 and 44 ~o
that ~uit~bly sized and shaped ~ectiona 40 and 41 of web such as
shown in Figure~ 2, 3, etc., fit directly into the qpace3,
thereby takin~ up less v~rtical room in the interior of the
footwear. The web section~ 40 and 41 compri~ing the "midsole"
are also thus held effectively in place against lateral
movement. It i8, of cour~e, po~sible to provide only one of the
s~ctlons 40 and 41.
Figure 10 illustrates an embodiment of the invention in
which a ~ection of the web 10 ~uch a~ shown in Figure 2 i~
provided with plugs 50, which are ~olid plug_ inqtead of the
,
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'091/1192X 2 fJ 7 ,~ n~ ~ 9 PCr/US~1/00590
hollow plugs 11 ~hown in Figure 2. It may be necessary to u3e
even qofter material for the plugs 50, in order to maintain the
desired high degre~ of compre~ ility, yi~lding a suitable
extent to compression under the ~tep of a wearer, while allowing
the plug to bulge, and recover.
Figure 11 show3 still another embodiment of the present
invention in which a portion of the web 10 similar to that in
Figure ~ i8 provlded with up~tanding plugs 51 which are hollow,
but essentially s~uare in cross section. These various deqign
parameters may be varied in order to achieve a maximum
performance. Such variables as the resiliency of the plastic
material, the height and ~hape of the plug~, the distribution
and number of the plugs per unit of area, variations in the
height~ of variou8 plug~, or row~ of plug~, hollow versu~ solid
plugs, and the thickne~s of the walls in such hollow plugs, can
all be varied for the purpose of achieving the objectives of the
pre~ent invention. Satisfactory re~ult~ hav~ been obtained
using plugs having a cross-sectional area of appr. 0.5 cm2 with
a wall thickneqs of 1 to 3 mm if holiow.
Figure 12 ~hows a further variation of the invention, in
which the plugs are not all of the same length, wherein in
insert 41 similar to the one ~hown in Figure 9, for the toe
portion of a ~hoe or ~andal, as may be seen from Figure 12, the
plugs 11 grow progressively ~hor er through plugs ~2 to 53 a~
they approach the toe. The lengths of the plug8 may be ~aried
in any suitable manner to accommodate the geometry of the inside
of the item of footwear.
Figure 13 show~ a further embodiment of a portion of a web
in accordance with the present invention, wherein the plug~ in
the upper and lower webs are facing each other for added
cushioning. Again, the upper web should be flexible and
preferably al80 air-permeable.
In Figure 14, the inner part of a heel section 60 of an
outsole or mid~ole is ~hown which ha~ a square rece~s 61 in it.
The rece~s 61 ha~ inserted therein a single large diameter
cylindrical plug 62 which is shown in it~ fully compressively
deformed position for explanatory purposes. A~ may be seen, the
WO~ Jg28 2B7 ~-J5'i PCT/~Sgl/005~0
compre~lv~ deformation i 9 causing the plug 62 to bulge but, of
course, only to partially fill in the space between it3
circumfor~nce and the corner~ of the racess 61, thus pumping air
upwards every time the plug 62 bulges.
In Figure 15, a heel section 70 of a women 8 shoe or sandal
is shown, which ha~ shown in it, for purposes of explanation,
cylindrical rece~e0 71 and rectangular recess 72. Of course,
any other polygonal rece~ may be u~ed. Plugs 73 and 74, when
installe~ in the rece~se~ stick out as desired due to the
recesses being shallower than the thickness or length of the
plug9 .
