CA1192739A - Dynamic support system for athletic shoes - Google Patents
Dynamic support system for athletic shoesInfo
- Publication number
- CA1192739A CA1192739A CA000421200A CA421200A CA1192739A CA 1192739 A CA1192739 A CA 1192739A CA 000421200 A CA000421200 A CA 000421200A CA 421200 A CA421200 A CA 421200A CA 1192739 A CA1192739 A CA 1192739A
- Authority
- CA
- Canada
- Prior art keywords
- midsole
- wearer
- board
- running
- heel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B5/00—Footwear for sporting purposes
- A43B5/06—Running shoes; Track shoes
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B13/00—Soles; Sole-and-heel integral units
- A43B13/02—Soles; Sole-and-heel integral units characterised by the material
- A43B13/12—Soles with several layers of different materials
Abstract
Abstract Of Disclosure An athletic running shoe having a polymeric foamed midsole and a special stiffening formation formed separately of the midsole and received between two layers of the midsole to stiffen the midsole along a pre-selected region.
Description
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DYNAM~C SIJPPO~T SYSTEM
FOR AT~ILFTIC SHOES
Fie]d of Inventiorl This inven~ion relates to athletic shoes ~nd is ~articu-larly concerned with running or jogging shoes of the type having a closed cell polymeric foamed rnidsole.
Backgrouncl Present day sliplasted and boardlasted running and jogging shoes, as well as other types of athle~ic shoes, are customarily manufactured with a laminate bottom construc~ion having a closed cell polymeric foam midsole overlying and adhered to a fle~:ible outsolev Sliplasted athletic running shoes mainly differ from boardlasted athletic shoes in that they have no insole board and instead have a closed fabric bottom to extend completely around the foot like a slipper. In the boardlasted athletic running shoes, the uppex has an open bottom which is closed by an insole board overlying the midsole. The foamed midsole is used in both types of shoes because of its lightness 2nd shock absorbing propexties to cushion the wearer's foot ayains-t im-pacts during runningO
Sliplasted athletic shoes ~re generally preferred over boardlasted athletic shoes because they usually are more com~
fortable than boardlasted athletic shoes. Due to the absence of an insole board, however, sliplasted athletic shoes are usually less stable than boardlasted athletic shoes because concentra~ed stresses are developed in the fo~ned midsole during xunnirlg to non-uniformly clegrade the foamed midsole to an objectionable extent. The foamed midsole therefore loses much of its effectiveness as a shock absorber because o the non-uniform deyradation~
,~
Degradation of the foamed midsole arises from con-tinual stresses which are developed by the repeated and cyclic defor-mation and relaxation of the midsole during the course o~
running. The degradation may take ~he form of a permanent compressive deformatiorl or compression set, as it is called, of the midsole. It mayialso occur without compression set ~here there is a breakdown or loss of the closed cells in the foamed midsole.
Midsole degradation is frequently localized due to con-cen~rated Eorce patterns which arise from a runner's particular running style. For example/ localized midsole degradation may occur at the rear outside border of the shoe in the region of the back of the heel. Midsole degradation also occurs through-ou~ the impact absorbing region of the midsole as a result of the compressive forces which cause the midsole to expand laterally outwardly of the shoe.
Localized midsole degradation along either the medial inside or lateral outside shoe edges is particularly trouble-some because it tends to cause the shoe to lose its stability by tilting as the runner's foot strikes the ground. To compensate for the instability, the runner may adjust his running style which, in turn, could lead to foot or ankle injuries.
Furthermore, the problem of midsole degradation is compounded by the fact that it frequently occur5 before the outsole loses its service life.
The foamed midsole in a boardlasted athletic running shoe will also degrade as a result of usage, but the degradation is no~ as non-uniform as the midsole degradation in a s:Liplasted athletic shQe becau~e ~he insole board of the boardlasted ath-le tic shoe disperses ~he ~orces a~ting on the midsole to some extent as long as ~he 1n~1~ b~rd i~el~ do~ ~ot degrade.
.. . . . . . . .
, . . ," , s , ~
DYNAM~C SIJPPO~T SYSTEM
FOR AT~ILFTIC SHOES
Fie]d of Inventiorl This inven~ion relates to athletic shoes ~nd is ~articu-larly concerned with running or jogging shoes of the type having a closed cell polymeric foamed rnidsole.
Backgrouncl Present day sliplasted and boardlasted running and jogging shoes, as well as other types of athle~ic shoes, are customarily manufactured with a laminate bottom construc~ion having a closed cell polymeric foam midsole overlying and adhered to a fle~:ible outsolev Sliplasted athletic running shoes mainly differ from boardlasted athletic shoes in that they have no insole board and instead have a closed fabric bottom to extend completely around the foot like a slipper. In the boardlasted athletic running shoes, the uppex has an open bottom which is closed by an insole board overlying the midsole. The foamed midsole is used in both types of shoes because of its lightness 2nd shock absorbing propexties to cushion the wearer's foot ayains-t im-pacts during runningO
Sliplasted athletic shoes ~re generally preferred over boardlasted athletic shoes because they usually are more com~
fortable than boardlasted athletic shoes. Due to the absence of an insole board, however, sliplasted athletic shoes are usually less stable than boardlasted athletic shoes because concentra~ed stresses are developed in the fo~ned midsole during xunnirlg to non-uniformly clegrade the foamed midsole to an objectionable extent. The foamed midsole therefore loses much of its effectiveness as a shock absorber because o the non-uniform deyradation~
,~
Degradation of the foamed midsole arises from con-tinual stresses which are developed by the repeated and cyclic defor-mation and relaxation of the midsole during the course o~
running. The degradation may take ~he form of a permanent compressive deformatiorl or compression set, as it is called, of the midsole. It mayialso occur without compression set ~here there is a breakdown or loss of the closed cells in the foamed midsole.
Midsole degradation is frequently localized due to con-cen~rated Eorce patterns which arise from a runner's particular running style. For example/ localized midsole degradation may occur at the rear outside border of the shoe in the region of the back of the heel. Midsole degradation also occurs through-ou~ the impact absorbing region of the midsole as a result of the compressive forces which cause the midsole to expand laterally outwardly of the shoe.
Localized midsole degradation along either the medial inside or lateral outside shoe edges is particularly trouble-some because it tends to cause the shoe to lose its stability by tilting as the runner's foot strikes the ground. To compensate for the instability, the runner may adjust his running style which, in turn, could lead to foot or ankle injuries.
Furthermore, the problem of midsole degradation is compounded by the fact that it frequently occur5 before the outsole loses its service life.
The foamed midsole in a boardlasted athletic running shoe will also degrade as a result of usage, but the degradation is no~ as non-uniform as the midsole degradation in a s:Liplasted athletic shQe becau~e ~he insole board of the boardlasted ath-le tic shoe disperses ~he ~orces a~ting on the midsole to some extent as long as ~he 1n~1~ b~rd i~el~ do~ ~ot degrade.
.. . . . . . . .
, . . ," , s , ~
-2 . . . . . .
A1-though an insole hoarcl does d.isperse the forc-es ac-ting on the foamed midsole -to some ex-tent, it was found tha-t if the insole board is made stiff enough to adequately spread the forces over the Eoamed midsole, the shoe becomes -too hard, causing appreciable discomfor-t to the wearer. On the other hand, low strength insole boards which meet the wearer's com-for-t requirements are likely to degrade, -thus giving rise to excessive non-uniform midsole degradation even in boardlasted shoes.
Summary of the Invention The inven-tion provides in an athletic shoe for running and other sports involving running, an upper and a bot-tom, said upper overlying and being attached to a part of said bottorn, said bottom comprising a flexible outsole and a flexible shock-absorbing midsol.e overlying and secured to said outsole, and said midsole being formed from a foamed polymeric material, the improvement comprising formation means formed separately of said midsole and engaging said midsole along a pre-selec-ted surface area underlying the wearer's foot and loca-ted inter-mediate -to the upper and lower surEaces of said midsole for stiffening said midsole along said pre-selected surface area.
The novel structure is designed to improve the stability of -the athletic shoe, reduce midsole degradation, and enhance the anatomical suppor-t for the wearer's foot, all with-out making the shoe uncomfortably hard and without using any parts which reduce the foot-receiving volume of the upper. The structure can substantially reduce the non-uniform rnidsole degradation of a sliplasted athletic shoe without resorting -to an insole boar~ and without otherwise impairing the comfor-t pro-perties of a slip]asted athle-tic shoe.
In the illustrated embocliment, the forma-tion means takes the form of a thin, stiff, subs-tantial:ly non-s-tre-tchable -3c~
73~
layer or stif:Eening board, as it may be called, which lies between and is adhered to two midsole layers at a level lying between -the upper and lower surfaces of the midsole. 'L'he stiffening board is required to be sufficiently s-ti:f.E to ef:Eectively disperse the forces acting on the shoe -throuc3holl-t the region covered -3a-~2~3~
by the board to thereby provide for a more uniform distribution of the Eorces acting on the shoe.
Because the stiffening board of this invention is effect~
ive in stiffening the foamed midsole support underneath the foot, its geometrical shape is particularly important. In the illustrated embodiment, the shape of the stiffening board is such that it underlies the wearer's entire rearfoot or heel region and ex~ends forwardly approximately to the first, second and third metatarsal heads to underlie the inside arch, but not the outside arch of the wearer's midfoot.
Because of the selected region covered by the stiffening board! the board does not interfere with the required flexure of the shoe~ It therefore may be made as stiff as possible ~ut not so stiff that it becomes brittle.
By dispersing the forces acting on the midsole, the stiffening board of this invention significantly reduces dele-terious, non-uniform midsole degradation and substantially lengthens the useful life of the shoe. The adherence of the stiffening board to the opposing midsole layers by itself has the effect of restraining the outward lateral expansion of the midsole due to compressive forces, thereby reducing midsole degradation due to such outward expansion. The degradation resulting from outward expansion of the midsole takes the form of cell wall fail~es which are caused by shear orces acting on the midsole material.
By locating the stiffening board of this invention at a level intermediate to the upper and lower surfaces of the mid-sole and by utilizing a boardless insole (i.e., a sliplasted construction without an insole board~, the foot support system is advantageously lowered. The foamed midsole layer underlying the stiffening boa~rd is used solely for absQrbing forces resultiny ~4
A1-though an insole hoarcl does d.isperse the forc-es ac-ting on the foamed midsole -to some ex-tent, it was found tha-t if the insole board is made stiff enough to adequately spread the forces over the Eoamed midsole, the shoe becomes -too hard, causing appreciable discomfor-t to the wearer. On the other hand, low strength insole boards which meet the wearer's com-for-t requirements are likely to degrade, -thus giving rise to excessive non-uniform midsole degradation even in boardlasted shoes.
Summary of the Invention The inven-tion provides in an athletic shoe for running and other sports involving running, an upper and a bot-tom, said upper overlying and being attached to a part of said bottorn, said bottom comprising a flexible outsole and a flexible shock-absorbing midsol.e overlying and secured to said outsole, and said midsole being formed from a foamed polymeric material, the improvement comprising formation means formed separately of said midsole and engaging said midsole along a pre-selec-ted surface area underlying the wearer's foot and loca-ted inter-mediate -to the upper and lower surEaces of said midsole for stiffening said midsole along said pre-selected surface area.
The novel structure is designed to improve the stability of -the athletic shoe, reduce midsole degradation, and enhance the anatomical suppor-t for the wearer's foot, all with-out making the shoe uncomfortably hard and without using any parts which reduce the foot-receiving volume of the upper. The structure can substantially reduce the non-uniform rnidsole degradation of a sliplasted athletic shoe without resorting -to an insole boar~ and without otherwise impairing the comfor-t pro-perties of a slip]asted athle-tic shoe.
In the illustrated embocliment, the forma-tion means takes the form of a thin, stiff, subs-tantial:ly non-s-tre-tchable -3c~
73~
layer or stif:Eening board, as it may be called, which lies between and is adhered to two midsole layers at a level lying between -the upper and lower surfaces of the midsole. 'L'he stiffening board is required to be sufficiently s-ti:f.E to ef:Eectively disperse the forces acting on the shoe -throuc3holl-t the region covered -3a-~2~3~
by the board to thereby provide for a more uniform distribution of the Eorces acting on the shoe.
Because the stiffening board of this invention is effect~
ive in stiffening the foamed midsole support underneath the foot, its geometrical shape is particularly important. In the illustrated embodiment, the shape of the stiffening board is such that it underlies the wearer's entire rearfoot or heel region and ex~ends forwardly approximately to the first, second and third metatarsal heads to underlie the inside arch, but not the outside arch of the wearer's midfoot.
Because of the selected region covered by the stiffening board! the board does not interfere with the required flexure of the shoe~ It therefore may be made as stiff as possible ~ut not so stiff that it becomes brittle.
By dispersing the forces acting on the midsole, the stiffening board of this invention significantly reduces dele-terious, non-uniform midsole degradation and substantially lengthens the useful life of the shoe. The adherence of the stiffening board to the opposing midsole layers by itself has the effect of restraining the outward lateral expansion of the midsole due to compressive forces, thereby reducing midsole degradation due to such outward expansion. The degradation resulting from outward expansion of the midsole takes the form of cell wall fail~es which are caused by shear orces acting on the midsole material.
By locating the stiffening board of this invention at a level intermediate to the upper and lower surfaces of the mid-sole and by utilizing a boardless insole (i.e., a sliplasted construction without an insole board~, the foot support system is advantageously lowered. The foamed midsole layer underlying the stiffening boa~rd is used solely for absQrbing forces resultiny ~4
3~
from the impact of the foo-t on the ground. The midsole l,ayer overlying the stiffening board a]so ac-ts as a shock ab.sorber and additi.onally cushlons the wearer's foot so that the shoe does not feel hard due to the presence o:E the stifEening board.
Furthermore, the foamed midsole ],ayer overlyiny the sti,Efening board in the region of the wearer's rearfoot is of suEficient thickness to closely conform -to -the shape of the wearer's heel, thereby enhancing the cornfort qualities of -the shoe.
By stiffening the foamed midsole in the manner described above, the extent of penetration of the runner's foot into the midsole is advantageously reduced by selectively increasing the stiffness of the midsole material. By extending the stiffening board to a region where it underlies the inside or medial arch-supporting region of the midsole, the stiffening board and foamed midsole also advantageously acts as a comfort-able dynamic arch support~ This aspec-t of the present invention eliminates the need for arch cookies or other conventional arch supporting inserts which disadvantageous]y reduce the foot-receiving volume of the shoe upper.
The midsole stiffening formation of -this invention may advantageously be manufactured separately from the shoe as a customized product for use by podiatrists and orthopedists in modifying existing running shoes to compensate for leg and foot asymmetries or other problems. Heretofore, various shoe inserts, such as heel cushions, arch supports and other so-called orthotic devices, have been used for this purpose. I'hey all have the common disadvantage of causing some discomfort because they take up foot-receiving space in the shoe upper.
In contrast to these prior shoe inser-ts, the stiffen--30 ~ ing forma-tion of -this invention lies in the midsole, and not in the upper so that the full volurne of the upper remains available for comfor-tably covering -the wearer's foo-t.
The athletic shoe disclosed has a novel midso]e con-struction wherein a special formation engages the Eoamed mid-sole body to reduce or retard deleterious, non-uniform degrada--tion oE the foamed midsole. The novel midsole has a dynarnic arch support. The midsole construc-tion is economical and easy to manufacture.
The invention also provides a method of modifying an exis-ting athletic running shoe having a polymeric foamed mid-sole, comprising the steps oE cutting the midsole to provide aformation-receiving space lying between the upper and lower surfaces of the midsole, inserting a stiff formation of pre-selected configura-tion into said space -to stiffen the midsole along a pre-selected surface area, and adhering the formation to the rnidsole.
The invention can provide a novel, customized forma--tion for modifying existing athletic shoes for -the purpose of accommodating a wearer's particular anatomy or asymmetries, and to compensate for different body weights and/or difEerent leg lengths.
7~ ~
Description of Drawings Figure 1 is a perspective view of a left-hand athletic running shoe incorporating the p.rinciples of this invention;
Figure 2 is a lonyitudi.nal section of the athletic runnirlg shoe shown in Figure l;
Figure 3 is a horizontal section taken substantiall~
along lines 3-3 of Figure 2 and showing the configuration of the stiffening formation according to one embodiment of this invention;
Figure 4 is a transverse seckion taken substantially along lines 4 4 of Figure 2;
Figure 5 is a further transverse section taken substan-tially along lines 5-5 of Figure 2;
Figure 6 is a transverse section similar to Figure 4 but showing a variation which is applicable for runners who pronate excessively; and Figure 7 is another transverse section similar to Figure
from the impact of the foo-t on the ground. The midsole l,ayer overlying the stiffening board a]so ac-ts as a shock ab.sorber and additi.onally cushlons the wearer's foot so that the shoe does not feel hard due to the presence o:E the stifEening board.
Furthermore, the foamed midsole ],ayer overlyiny the sti,Efening board in the region of the wearer's rearfoot is of suEficient thickness to closely conform -to -the shape of the wearer's heel, thereby enhancing the cornfort qualities of -the shoe.
By stiffening the foamed midsole in the manner described above, the extent of penetration of the runner's foot into the midsole is advantageously reduced by selectively increasing the stiffness of the midsole material. By extending the stiffening board to a region where it underlies the inside or medial arch-supporting region of the midsole, the stiffening board and foamed midsole also advantageously acts as a comfort-able dynamic arch support~ This aspec-t of the present invention eliminates the need for arch cookies or other conventional arch supporting inserts which disadvantageous]y reduce the foot-receiving volume of the shoe upper.
The midsole stiffening formation of -this invention may advantageously be manufactured separately from the shoe as a customized product for use by podiatrists and orthopedists in modifying existing running shoes to compensate for leg and foot asymmetries or other problems. Heretofore, various shoe inserts, such as heel cushions, arch supports and other so-called orthotic devices, have been used for this purpose. I'hey all have the common disadvantage of causing some discomfort because they take up foot-receiving space in the shoe upper.
In contrast to these prior shoe inser-ts, the stiffen--30 ~ ing forma-tion of -this invention lies in the midsole, and not in the upper so that the full volurne of the upper remains available for comfor-tably covering -the wearer's foo-t.
The athletic shoe disclosed has a novel midso]e con-struction wherein a special formation engages the Eoamed mid-sole body to reduce or retard deleterious, non-uniform degrada--tion oE the foamed midsole. The novel midsole has a dynarnic arch support. The midsole construc-tion is economical and easy to manufacture.
The invention also provides a method of modifying an exis-ting athletic running shoe having a polymeric foamed mid-sole, comprising the steps oE cutting the midsole to provide aformation-receiving space lying between the upper and lower surfaces of the midsole, inserting a stiff formation of pre-selected configura-tion into said space -to stiffen the midsole along a pre-selected surface area, and adhering the formation to the rnidsole.
The invention can provide a novel, customized forma--tion for modifying existing athletic shoes for -the purpose of accommodating a wearer's particular anatomy or asymmetries, and to compensate for different body weights and/or difEerent leg lengths.
7~ ~
Description of Drawings Figure 1 is a perspective view of a left-hand athletic running shoe incorporating the p.rinciples of this invention;
Figure 2 is a lonyitudi.nal section of the athletic runnirlg shoe shown in Figure l;
Figure 3 is a horizontal section taken substantiall~
along lines 3-3 of Figure 2 and showing the configuration of the stiffening formation according to one embodiment of this invention;
Figure 4 is a transverse seckion taken substantially along lines 4 4 of Figure 2;
Figure 5 is a further transverse section taken substan-tially along lines 5-5 of Figure 2;
Figure 6 is a transverse section similar to Figure 4 but showing a variation which is applicable for runners who pronate excessively; and Figure 7 is another transverse section similar to Figure
4 but showing a further variation which is applicable to runners who supinate excessively.
Detailed Description In this specification, the term "rearfoot" is used to identify the heel portion of the foot containing the heel bone, the term "midfoot" is used to identify the intermediate portion of the foot lying adjacent to the rearfoot and containing the five bones which are connected together to form the beginning of the arches in the foot, and the term "forefoot" is used to identify the foot portion lying adjacent to the midfoot and containing the metatarsals.
Although the midsole stif~ening formation of this invention i~ incorporated lnto a slipla~t~d athletic running shoe in the illust.rated embodimén~l it will be appreciated ~hat , ;
73~
the principles of the subjec-t invention are also applicable to athletic shoes having an insole board where the insole board is made sufficiently flexible so that it does not impair the f~tnctions of the special stiffeniny formation o~
this invention.
Referring to Figure5 1 and 2, the athletic running shoe incorporating the principles of this invention comprises a flexible, sliplasted upper 10, a bottom 12 underlying upper 10 and a soft, pliable sliplasted insole 13 (see Figure 2).
Upper 10 has a closed fabric bottom 15 so that it extends completely around the foot in the customary manner. Insole 13 is received in upper 10 and overlies the fabric bottom 15.
The upper 10 may be of any suitable, conven-tional con-struction and is shown to comprise a toe portion or toe box 14, a vamp portion 16, a heel portion 18, foxing 20 wrapped around the back of the heel portion, a throat 22 extending alony the vamp portion 16 for the lacing which is indicated at 24, a padded tongue 26 extending along throat 22, and a padded collar 28 extending aroun~ the shoe's foot-receiving opening.
The shoe bottom 12 i9 a laminated construction having a flexible, ground-engaging outsole 32 and a shock-absorbing midsole 33 ovsrlying and bonded to the outsole 32. The outsole 32 may be of any suitable construction and may be fabricated from synthetic or natural rubber material. The ground-engaging surface of outsole 32 is preferably formed with a suitable tread pattern 36. The midsole 33 is substantially coextensive with the outsole 32. The upper 10 is bonded or otherwise suitably secured to midsole 33 along its fabric bottom 15.
The midsole 33 is formed from any suitable closed cell polymeric foam shock absorbing material. For example~ the mid-sole 33 may be formed ~from a blend of ethylene vinyl acetate ~ f~
f~ J~
and polyethylene and then cross-linked with a peroxi~c dUl^illCJ
molding. The foam material is preferably lightweight haviny a density on the order of 0.2 grams per cubic centim~ter or somewhat less.
MidsoIe 33 is the ~hickes~ at its rearfoot or heel portion 39 where it undérlies the wearerls heel or rearfoot.
In the illustrated embodiment, the midsole's heel portion 39 `
is of substantially uniform thickness. Midsole 33 tapers for-wardly at an intermediate region lying forwardly of the heel portion 39 to form a wedge as shown in Figures 1 and 2. The wedge may be formed separately of midsole 33 and it may overlie or underlie the midsole.
In the illustrated embodiment, the midsole stiffening formation of this invention is in the form of a thin, stiff, planar, flat-sided layer 37 or stiffening board, as it may also be calledO The stiffening board 37 is formed separately of the foamed midsole 33 and is incorporated into the midsole in a manner to be described in detail later on.
In the illustrated embodiment, the insole 13 comprises a soft, flexible, flat cushion liner 38 for the wearer's sock. Liner 38 overlies the fabric bottom 15 of upper 10 and may be formed from any suitable pliable material such as a foam material or terrycloth. Insole 13 is characterized by the fact that it does not have an insole board.
As shown in Figures 1-5, stiffening board 37 is recei~ed in a slit 42 which is formed in midsole 33 between the upper and lower surfaces of the midsole to partially divide midsole 33 into upper and lower layers 44 and 46, respectively. Stiff-ening board 37 is glued or otherwise su'tably adhered to the bott~m sur~ace o~ the midsole layer 44 and to the upper surf aee of the lower midsole 1ayer 46. ~ny suitable adhesive may be used ~9_ 27~3~ ~
for adhering stiffening board 37 to the midsole layers 44 and 46. Preferably, the adhesive is applied throuyhout the entire interface between stiffeniny board 37 and the midsole layer 44 and also throuyhout the entire interface betwe~n the stiffening board 37 and the lower midsole layer 46.
Slit 42 extends parallel to or at least yenerally parallel to the outsole 32 when the shoe bottom is in its straiyht, unflexed condition.
With the possible exception of the midsole's rearmost heel reyion which may be tapered as shown in Fiyure 2, the lower midsole layer 46 is provided with a substantially uniform thickness throughout the length and width o~ slit 42. The rearfoot section of the upper midsole layer 44 underlying the wearer's rearfoot or heel also has a substantially uniform thickness.
Slit 42 is formed in midsole 33 at a level lying about midway between or slightly below the upper and lower edges of the midsole's rearfoot section. The level of slit 42, in any case, is required to be low enough to provide the upper midsole layer 46 with a thickness that is sufficient to keep the weareris foot rom bottomlng on stiffening board 37 during m~;mum expected impact on the midsole. The thickness and other dimensions of midsole 33 may be customary, suitable values presently used in the shoe industry to manufacture running shoes.
At a region centrally underlying the wearer's rearfoot or heel, the overall thickness of midsole 33 may, for example, be about 3/4 inches and the height of slit 42 above the lower edge of the midsole may be about 5/16 inches.
As shown in Figures 1-3, the configuration or outline of slit 42 conforms to that of stiffening board 37 to snugly and ully receive the stiffening board. Slit 42 extends throughout ~9~73'~ ~
the rearfoot or heel portion of midsole 33 so that it opens completely around the midsole's rearfoot portion at the hack and also at both sides. From the rearfoot portion of midsole 33, slit 42 extends forwardly along and opens at the inside or medial border of the shoe approximately to the first metatarsal head to underlie the we.irer's inside arch.
It will be appreciated that stiffenirly board 37 may be assembled with midsole 33 in any suitable manner. For e~ample, after slit 42 is formed in the midsole and an adhesive is applied to both sides of stiffening board 37, the stiffening board may be fully inserted into slit 42. The mldsole layers 44 and 46 and stiffening board 37 may then be pressed together to firmly adhere the stiffening board to the midsole layers 44 and 46.
Stiffening board 37 is formed from any suitable, durable substantially non-stretchable material. For example, it may be a sti~f composite material sheet formed from polyester resin and woven or chopped fiberglass in which the amount of fiber-glass present is equal to approximately 25 percent by volume of the sheet.
The stiffening board's minimum flexural or bending modulus required for an adequate dispersion or spreading of the forces acting on midsole 33 is dependent on the thickness of the stiffening board. The thickness for stiffening board 37 should normally be at least approximately 0.05 inches and preferably is approximately 0.06 inches (about 1~16 inch). r'Ol-a stiffening board thickness of 0.05 inches, the bending or flexural modulus is required to be at least 1,000,000 psi and is more preferably about 2,000,000 psi.
As sho~n in Figure 31 stiffening board 37 extends through-out the rearfoot region of the ~hoe bottom to the outer edge 3~
o~ th~ hecl alld from o~ le of ~l~c midsole ~o ~l~e oLIIer.
From the rear of midsole 33, stiffening board 37 e~ellds forwardly along the shoe's medial or inside 'oorder to the location 50 which is proximal to the wearer' 5 first metatarsal head. ~rom here, the edge or perimeter of sti.ff~ning board 37 arcs posteriorly and .Latera:Lly along a line 51 which i5 proxirnal to the wearer's second and third metatarsal heads. The edge of the stifening board then turns to take a direct longitu-dinally extending line 52 posteriorly to a region underlying the wearer's cuboid where it arcs out at 53 to extend laterally to the lateral or outer border of the shoe bottom along a line 54 lying approximately normal to the shoe's longitudinal axis at the forward end of the midsole's rearfoot or heel section 39.
By the foregoing construction, it is clear that stiffen-ing board 37 underlies the wearer's entire rearfoot and extends forwardly to underlie the wearer's inside arch along the medial border, but not khe wearer's outside arch or the forefoot region extending forwardly of the wearer's first, second and third metatarsal heads. Because of the selected area covered by stifrening board 37, the board does not in~erfere with the requiredflexure of the running shoe. It therefore may be made as stiff as desired without making ik brittle.
Stiffening board 37 is preferably feathered or skived to a taper along .its curved, forward edge (see lines 51-54) as indicated at 56 in Figure 3 to keep the wearer from sensing or feeling an abrupt change in stiffrless due to the stiffening board edge as he presses clown on the shoe bottom. Additionally, the rear lateral or outside corner 58 (see ~igure 3) may also be similarly skived ko avoid the development of stress concen-~trations at the most con~on first heel strike region and also ~ Z~3~
-to eliminate or signlficantly reduce accelerated, deleterious sole wear due to the presence of stif~eni.ng board 37.
The lower midsol~ layer 46 functions solely as a shock absorber for absorbi.ny the forces resultiny rom impact of the runner's foot on the ground. The upper midsole layex 44 also acts as a shock absorber for absorbing such forces and additionally cushions the wearer's foot so that the shoe does not feel hard due to the presence of stiffening board 37.
Furthermore, the thickness of the upper midsole layer 44 in the region of the wearer's rearfoot or heel is sufficient to closely conform or mold itself to the shape of the wearer's heel to provide additional comfort for the wearer.
By stiffeniny midsole 33 in the manner described above, the extent of penetration of the runner's foot into the upper midsole layer 44 overlying stiffening board 37 is advantageously and significantly reduced as compared with a conventional shoe without the stiffening formation of this invention. The stiffening effect encountered at initial deformation or pene-tration of ~he wearerls foot into the upper midsole layer 44 is approximately douhled by the presence o stiffening board 37 in midsole 33, with the result that energy is absorbed at about twice the rate of a conventional shoe. Although the maximum force will be increased over a new conventional shoe, it never~
theless will still be acceptably low. In addition, conventional shoes are known to frequently lose about half of their energy absorbing properties due to continuous use as, for example, while running a marathon distance~
Reducing the extent of rearfoot penetration into midsole 33 has the advantageous effect of enabling the runner ~o have greater control o~er h.is rearfoot motion, thus .improviny rear-foot .stahility withouk any significant tradeoff of the shock 3~ ~
absorbing properties of the midsole 33.
By extending stiffening board 37 to a region where it underlies the runner's inside or med.ial arch, the composite of -the midsole 33 and the stiffening board 37 ~mderlyiny the inside arch establishes a comfortable arch suppo.r-t fo.r the wearer which .is dynamic in -the sense that .it is felt only ~7ith the application of substantial forces. This eliminates the need for arch cookies or other conven-tional arch-supporting inserts which are placed in the shoe upper and which dis-advantageously reduce the foot-receivi.ng volume of the shoe upper.
Stiffening board 37 acts to reduce midsole degradation in two ways. First, it is sufficiently stiff to effectively disperse or spread out the forces acting on midsole 33 through-out the area or region of the stiffening board to thereby provide for a more uniform distribution of the forces acting on midsole 33 in the region of the stiffening board. Stiffen-ing board 37 thus eliminates or substanti~lly reduces large, concentrated force patterns resulting from a runner's particu-lar running style and consequently reduces non~uniform degrada-tion of midsole 33.
Second, stiffening board 37 has the effect of restrain-ing outward lateral expansion of midsole 33 under the influence of compressive forces because of its adherence to the midsole layers 44 and 46 and because of its substantially non-stretchable properties. The tensile properties of the midsole foam cel]
walls lying contiguous to the adhesive surfaces will therefore act to restrain the outward expans.ion under the influence of the compressive forces. While some outward midsole expansion will occur because of these compressive forces/ the extent of the outward expansion in each of the midsole layers 44 and 46 2~3~
will never-theless be subs-tantially less than the c~pansion that would talce place without -the stiffeniny formation of the present inventlon. Midsole degradation resulting frorn such outward expansion is therefore correspondingly reduced with the present invention.
From the foregolng construction, it is important to observe that the stiffening board 37 has the effect of signifi-cantly improving the stability of a new running shoe in which no midsole degradation has occurred. In this regard, stiffen-ing board 37 has the effect of dispersing off-centered or unbalanced forces created by a particular running style. Such dispersement produces a restoring force which opposes an un-balanced or off-centered landing of the foot where, for example, the runner lands on the ground along the outside or lateral border of the shoe instead of landing flat. Furthermore, stiffening board 37 provides an improved foot support during running by employing the midsole layer 44 as a cushion which comfortably conforms to the configuration of the wearer's heeL
while running and by further establishing a dynamic arch support for the runner's inside or medial archO In addition to the foregoing, stiffening board 37 significantly reduces non-uniform midsole degradation to substantially improve the stability of the running shoe over the long term and to sub-stantially lengthen the problem-free life of the shoe.
Because the outward expansion of the midsole is restrained just by the non-s-tretchable or tensile properties of stiffening board 37 and by the adherence of the stiffening board -to the midsole layers ~4 and ~6, such ou'ward midsole expansion may be reduced by using a fleXible, substantially non-stretchable layer or formation in place of stiffening board 37 and by adhering such a non-stretchable flexible formation or layer to the 7'~3~
midsole layers 44 and 46.
Instead of beiny molded in one piece and thereafter slit -to accommodate stiffening board 37, midsole 33 may be manufactured with two separately formed Eoamed layers, and these layers may have different densities. Because of the stiffeniny formation of this invention, differen-t foam materials not pre-viously thought to be suitable for midsoles may be used in the manufacture of the running shoe.
Stiffening board 37 is not required to lie horizontal-ly as shown in Figures 1-5. Instead, it may be tilted or rotated in one direction or the other about a longitudinal axis as shown in Figures 6 and 7.
In Figure 6, stiffening board 37 is tilted in a direc-tion to locate its side edge at the lateral or outside shoe bottom border at a level that is lower than i-ts side edge a-t the media] or inside shoe bottom border to compensate for the forces which are created by runners who pronate excessively. In Figure 7, stiffening board 37 is tilted in the opposite direction such that the side edge of the stiffening board at the medial or inside shoe bottom border is at a level lower than the opposite stiffening board side edge at the lateral or outside shoe bottom border to compensate for the forces created by runners who supinate excessively.
The midsole stiffening formation of this invention is not required to be flat or planar as is the case with s-tiffening board 37~ Stiffening board 37 may therefore be replaced with differently shaped stiffening formations. For example, the stiffening formation may have a curved or contoured configura-tion, and it may also be molded. Furthermore, var:ious factors associated with the s-tiffening formation of this invention may ~~ be suitably varied depending upon the circurnstances. For example, 3~
such factors as the thickness of the stiffening formation, the stiffness of the formation, -the geometrical ex-tent or area covered by the stiffening format.ion, and the p].acement height o the formatlon may all be varied -to accommodate different running styles, leg and foot asymmetries ancl body weights. ..
It also will be appreciated tha-t the stiffening formation of this invention avoids difficult and costly attempts to vary the suppor~ pattexn of the running shoe by introducing diferent elastomeric materials into the midsole foam.
~ urthermore, the midsole stiffening formation of this invention may advantageously be manufactured separately from the running shoe as a customized product or use by podiatrists and orthopedists for modifying existing or fully constructed shoes after they are manufactured to compensate for leg and foot asymmetries or other problems and to thereby customize the shoe to the individualO For example, the midsole stiffening formation of this inven-tion may be used to compensate for different leg lenyths with the added advantage of not requiring the insertion of any parts of components into the shoe upper itself. The method of using the stiffening formation in this manner mainly comprises the steps of first slitting the foamed midsole of an existing athletic shoe or otherwise forming a cavity in the midsole for receiving the stiffening formation, and thereafter inserting the specially formed stiffening for-mation into the slit or cavity and adhering the stiffening formation to the midsole~
It will be appxeciated that the parts of the athl.etic rl~nning shoe for ~he right foo~ are the mirror image of the previously described parts of the shoe or the left foo~.
The invention may be embodied in other specific forms ~17~
~2'~
wi-thout departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustratlve and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to he ernbraced therein.
What is claimed and desired to be secured by Let-ters Pa~ent i5:
. . .
Detailed Description In this specification, the term "rearfoot" is used to identify the heel portion of the foot containing the heel bone, the term "midfoot" is used to identify the intermediate portion of the foot lying adjacent to the rearfoot and containing the five bones which are connected together to form the beginning of the arches in the foot, and the term "forefoot" is used to identify the foot portion lying adjacent to the midfoot and containing the metatarsals.
Although the midsole stif~ening formation of this invention i~ incorporated lnto a slipla~t~d athletic running shoe in the illust.rated embodimén~l it will be appreciated ~hat , ;
73~
the principles of the subjec-t invention are also applicable to athletic shoes having an insole board where the insole board is made sufficiently flexible so that it does not impair the f~tnctions of the special stiffeniny formation o~
this invention.
Referring to Figure5 1 and 2, the athletic running shoe incorporating the principles of this invention comprises a flexible, sliplasted upper 10, a bottom 12 underlying upper 10 and a soft, pliable sliplasted insole 13 (see Figure 2).
Upper 10 has a closed fabric bottom 15 so that it extends completely around the foot in the customary manner. Insole 13 is received in upper 10 and overlies the fabric bottom 15.
The upper 10 may be of any suitable, conven-tional con-struction and is shown to comprise a toe portion or toe box 14, a vamp portion 16, a heel portion 18, foxing 20 wrapped around the back of the heel portion, a throat 22 extending alony the vamp portion 16 for the lacing which is indicated at 24, a padded tongue 26 extending along throat 22, and a padded collar 28 extending aroun~ the shoe's foot-receiving opening.
The shoe bottom 12 i9 a laminated construction having a flexible, ground-engaging outsole 32 and a shock-absorbing midsole 33 ovsrlying and bonded to the outsole 32. The outsole 32 may be of any suitable construction and may be fabricated from synthetic or natural rubber material. The ground-engaging surface of outsole 32 is preferably formed with a suitable tread pattern 36. The midsole 33 is substantially coextensive with the outsole 32. The upper 10 is bonded or otherwise suitably secured to midsole 33 along its fabric bottom 15.
The midsole 33 is formed from any suitable closed cell polymeric foam shock absorbing material. For example~ the mid-sole 33 may be formed ~from a blend of ethylene vinyl acetate ~ f~
f~ J~
and polyethylene and then cross-linked with a peroxi~c dUl^illCJ
molding. The foam material is preferably lightweight haviny a density on the order of 0.2 grams per cubic centim~ter or somewhat less.
MidsoIe 33 is the ~hickes~ at its rearfoot or heel portion 39 where it undérlies the wearerls heel or rearfoot.
In the illustrated embodiment, the midsole's heel portion 39 `
is of substantially uniform thickness. Midsole 33 tapers for-wardly at an intermediate region lying forwardly of the heel portion 39 to form a wedge as shown in Figures 1 and 2. The wedge may be formed separately of midsole 33 and it may overlie or underlie the midsole.
In the illustrated embodiment, the midsole stiffening formation of this invention is in the form of a thin, stiff, planar, flat-sided layer 37 or stiffening board, as it may also be calledO The stiffening board 37 is formed separately of the foamed midsole 33 and is incorporated into the midsole in a manner to be described in detail later on.
In the illustrated embodiment, the insole 13 comprises a soft, flexible, flat cushion liner 38 for the wearer's sock. Liner 38 overlies the fabric bottom 15 of upper 10 and may be formed from any suitable pliable material such as a foam material or terrycloth. Insole 13 is characterized by the fact that it does not have an insole board.
As shown in Figures 1-5, stiffening board 37 is recei~ed in a slit 42 which is formed in midsole 33 between the upper and lower surfaces of the midsole to partially divide midsole 33 into upper and lower layers 44 and 46, respectively. Stiff-ening board 37 is glued or otherwise su'tably adhered to the bott~m sur~ace o~ the midsole layer 44 and to the upper surf aee of the lower midsole 1ayer 46. ~ny suitable adhesive may be used ~9_ 27~3~ ~
for adhering stiffening board 37 to the midsole layers 44 and 46. Preferably, the adhesive is applied throuyhout the entire interface between stiffeniny board 37 and the midsole layer 44 and also throuyhout the entire interface betwe~n the stiffening board 37 and the lower midsole layer 46.
Slit 42 extends parallel to or at least yenerally parallel to the outsole 32 when the shoe bottom is in its straiyht, unflexed condition.
With the possible exception of the midsole's rearmost heel reyion which may be tapered as shown in Fiyure 2, the lower midsole layer 46 is provided with a substantially uniform thickness throughout the length and width o~ slit 42. The rearfoot section of the upper midsole layer 44 underlying the wearer's rearfoot or heel also has a substantially uniform thickness.
Slit 42 is formed in midsole 33 at a level lying about midway between or slightly below the upper and lower edges of the midsole's rearfoot section. The level of slit 42, in any case, is required to be low enough to provide the upper midsole layer 46 with a thickness that is sufficient to keep the weareris foot rom bottomlng on stiffening board 37 during m~;mum expected impact on the midsole. The thickness and other dimensions of midsole 33 may be customary, suitable values presently used in the shoe industry to manufacture running shoes.
At a region centrally underlying the wearer's rearfoot or heel, the overall thickness of midsole 33 may, for example, be about 3/4 inches and the height of slit 42 above the lower edge of the midsole may be about 5/16 inches.
As shown in Figures 1-3, the configuration or outline of slit 42 conforms to that of stiffening board 37 to snugly and ully receive the stiffening board. Slit 42 extends throughout ~9~73'~ ~
the rearfoot or heel portion of midsole 33 so that it opens completely around the midsole's rearfoot portion at the hack and also at both sides. From the rearfoot portion of midsole 33, slit 42 extends forwardly along and opens at the inside or medial border of the shoe approximately to the first metatarsal head to underlie the we.irer's inside arch.
It will be appreciated that stiffenirly board 37 may be assembled with midsole 33 in any suitable manner. For e~ample, after slit 42 is formed in the midsole and an adhesive is applied to both sides of stiffening board 37, the stiffening board may be fully inserted into slit 42. The mldsole layers 44 and 46 and stiffening board 37 may then be pressed together to firmly adhere the stiffening board to the midsole layers 44 and 46.
Stiffening board 37 is formed from any suitable, durable substantially non-stretchable material. For example, it may be a sti~f composite material sheet formed from polyester resin and woven or chopped fiberglass in which the amount of fiber-glass present is equal to approximately 25 percent by volume of the sheet.
The stiffening board's minimum flexural or bending modulus required for an adequate dispersion or spreading of the forces acting on midsole 33 is dependent on the thickness of the stiffening board. The thickness for stiffening board 37 should normally be at least approximately 0.05 inches and preferably is approximately 0.06 inches (about 1~16 inch). r'Ol-a stiffening board thickness of 0.05 inches, the bending or flexural modulus is required to be at least 1,000,000 psi and is more preferably about 2,000,000 psi.
As sho~n in Figure 31 stiffening board 37 extends through-out the rearfoot region of the ~hoe bottom to the outer edge 3~
o~ th~ hecl alld from o~ le of ~l~c midsole ~o ~l~e oLIIer.
From the rear of midsole 33, stiffening board 37 e~ellds forwardly along the shoe's medial or inside 'oorder to the location 50 which is proximal to the wearer' 5 first metatarsal head. ~rom here, the edge or perimeter of sti.ff~ning board 37 arcs posteriorly and .Latera:Lly along a line 51 which i5 proxirnal to the wearer's second and third metatarsal heads. The edge of the stifening board then turns to take a direct longitu-dinally extending line 52 posteriorly to a region underlying the wearer's cuboid where it arcs out at 53 to extend laterally to the lateral or outer border of the shoe bottom along a line 54 lying approximately normal to the shoe's longitudinal axis at the forward end of the midsole's rearfoot or heel section 39.
By the foregoing construction, it is clear that stiffen-ing board 37 underlies the wearer's entire rearfoot and extends forwardly to underlie the wearer's inside arch along the medial border, but not khe wearer's outside arch or the forefoot region extending forwardly of the wearer's first, second and third metatarsal heads. Because of the selected area covered by stifrening board 37, the board does not in~erfere with the requiredflexure of the running shoe. It therefore may be made as stiff as desired without making ik brittle.
Stiffening board 37 is preferably feathered or skived to a taper along .its curved, forward edge (see lines 51-54) as indicated at 56 in Figure 3 to keep the wearer from sensing or feeling an abrupt change in stiffrless due to the stiffening board edge as he presses clown on the shoe bottom. Additionally, the rear lateral or outside corner 58 (see ~igure 3) may also be similarly skived ko avoid the development of stress concen-~trations at the most con~on first heel strike region and also ~ Z~3~
-to eliminate or signlficantly reduce accelerated, deleterious sole wear due to the presence of stif~eni.ng board 37.
The lower midsol~ layer 46 functions solely as a shock absorber for absorbi.ny the forces resultiny rom impact of the runner's foot on the ground. The upper midsole layex 44 also acts as a shock absorber for absorbing such forces and additionally cushions the wearer's foot so that the shoe does not feel hard due to the presence of stiffening board 37.
Furthermore, the thickness of the upper midsole layer 44 in the region of the wearer's rearfoot or heel is sufficient to closely conform or mold itself to the shape of the wearer's heel to provide additional comfort for the wearer.
By stiffeniny midsole 33 in the manner described above, the extent of penetration of the runner's foot into the upper midsole layer 44 overlying stiffening board 37 is advantageously and significantly reduced as compared with a conventional shoe without the stiffening formation of this invention. The stiffening effect encountered at initial deformation or pene-tration of ~he wearerls foot into the upper midsole layer 44 is approximately douhled by the presence o stiffening board 37 in midsole 33, with the result that energy is absorbed at about twice the rate of a conventional shoe. Although the maximum force will be increased over a new conventional shoe, it never~
theless will still be acceptably low. In addition, conventional shoes are known to frequently lose about half of their energy absorbing properties due to continuous use as, for example, while running a marathon distance~
Reducing the extent of rearfoot penetration into midsole 33 has the advantageous effect of enabling the runner ~o have greater control o~er h.is rearfoot motion, thus .improviny rear-foot .stahility withouk any significant tradeoff of the shock 3~ ~
absorbing properties of the midsole 33.
By extending stiffening board 37 to a region where it underlies the runner's inside or med.ial arch, the composite of -the midsole 33 and the stiffening board 37 ~mderlyiny the inside arch establishes a comfortable arch suppo.r-t fo.r the wearer which .is dynamic in -the sense that .it is felt only ~7ith the application of substantial forces. This eliminates the need for arch cookies or other conven-tional arch-supporting inserts which are placed in the shoe upper and which dis-advantageously reduce the foot-receivi.ng volume of the shoe upper.
Stiffening board 37 acts to reduce midsole degradation in two ways. First, it is sufficiently stiff to effectively disperse or spread out the forces acting on midsole 33 through-out the area or region of the stiffening board to thereby provide for a more uniform distribution of the forces acting on midsole 33 in the region of the stiffening board. Stiffen-ing board 37 thus eliminates or substanti~lly reduces large, concentrated force patterns resulting from a runner's particu-lar running style and consequently reduces non~uniform degrada-tion of midsole 33.
Second, stiffening board 37 has the effect of restrain-ing outward lateral expansion of midsole 33 under the influence of compressive forces because of its adherence to the midsole layers 44 and 46 and because of its substantially non-stretchable properties. The tensile properties of the midsole foam cel]
walls lying contiguous to the adhesive surfaces will therefore act to restrain the outward expans.ion under the influence of the compressive forces. While some outward midsole expansion will occur because of these compressive forces/ the extent of the outward expansion in each of the midsole layers 44 and 46 2~3~
will never-theless be subs-tantially less than the c~pansion that would talce place without -the stiffeniny formation of the present inventlon. Midsole degradation resulting frorn such outward expansion is therefore correspondingly reduced with the present invention.
From the foregolng construction, it is important to observe that the stiffening board 37 has the effect of signifi-cantly improving the stability of a new running shoe in which no midsole degradation has occurred. In this regard, stiffen-ing board 37 has the effect of dispersing off-centered or unbalanced forces created by a particular running style. Such dispersement produces a restoring force which opposes an un-balanced or off-centered landing of the foot where, for example, the runner lands on the ground along the outside or lateral border of the shoe instead of landing flat. Furthermore, stiffening board 37 provides an improved foot support during running by employing the midsole layer 44 as a cushion which comfortably conforms to the configuration of the wearer's heeL
while running and by further establishing a dynamic arch support for the runner's inside or medial archO In addition to the foregoing, stiffening board 37 significantly reduces non-uniform midsole degradation to substantially improve the stability of the running shoe over the long term and to sub-stantially lengthen the problem-free life of the shoe.
Because the outward expansion of the midsole is restrained just by the non-s-tretchable or tensile properties of stiffening board 37 and by the adherence of the stiffening board -to the midsole layers ~4 and ~6, such ou'ward midsole expansion may be reduced by using a fleXible, substantially non-stretchable layer or formation in place of stiffening board 37 and by adhering such a non-stretchable flexible formation or layer to the 7'~3~
midsole layers 44 and 46.
Instead of beiny molded in one piece and thereafter slit -to accommodate stiffening board 37, midsole 33 may be manufactured with two separately formed Eoamed layers, and these layers may have different densities. Because of the stiffeniny formation of this invention, differen-t foam materials not pre-viously thought to be suitable for midsoles may be used in the manufacture of the running shoe.
Stiffening board 37 is not required to lie horizontal-ly as shown in Figures 1-5. Instead, it may be tilted or rotated in one direction or the other about a longitudinal axis as shown in Figures 6 and 7.
In Figure 6, stiffening board 37 is tilted in a direc-tion to locate its side edge at the lateral or outside shoe bottom border at a level that is lower than i-ts side edge a-t the media] or inside shoe bottom border to compensate for the forces which are created by runners who pronate excessively. In Figure 7, stiffening board 37 is tilted in the opposite direction such that the side edge of the stiffening board at the medial or inside shoe bottom border is at a level lower than the opposite stiffening board side edge at the lateral or outside shoe bottom border to compensate for the forces created by runners who supinate excessively.
The midsole stiffening formation of this invention is not required to be flat or planar as is the case with s-tiffening board 37~ Stiffening board 37 may therefore be replaced with differently shaped stiffening formations. For example, the stiffening formation may have a curved or contoured configura-tion, and it may also be molded. Furthermore, var:ious factors associated with the s-tiffening formation of this invention may ~~ be suitably varied depending upon the circurnstances. For example, 3~
such factors as the thickness of the stiffening formation, the stiffness of the formation, -the geometrical ex-tent or area covered by the stiffening format.ion, and the p].acement height o the formatlon may all be varied -to accommodate different running styles, leg and foot asymmetries ancl body weights. ..
It also will be appreciated tha-t the stiffening formation of this invention avoids difficult and costly attempts to vary the suppor~ pattexn of the running shoe by introducing diferent elastomeric materials into the midsole foam.
~ urthermore, the midsole stiffening formation of this invention may advantageously be manufactured separately from the running shoe as a customized product or use by podiatrists and orthopedists for modifying existing or fully constructed shoes after they are manufactured to compensate for leg and foot asymmetries or other problems and to thereby customize the shoe to the individualO For example, the midsole stiffening formation of this inven-tion may be used to compensate for different leg lenyths with the added advantage of not requiring the insertion of any parts of components into the shoe upper itself. The method of using the stiffening formation in this manner mainly comprises the steps of first slitting the foamed midsole of an existing athletic shoe or otherwise forming a cavity in the midsole for receiving the stiffening formation, and thereafter inserting the specially formed stiffening for-mation into the slit or cavity and adhering the stiffening formation to the midsole~
It will be appxeciated that the parts of the athl.etic rl~nning shoe for ~he right foo~ are the mirror image of the previously described parts of the shoe or the left foo~.
The invention may be embodied in other specific forms ~17~
~2'~
wi-thout departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustratlve and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to he ernbraced therein.
What is claimed and desired to be secured by Let-ters Pa~ent i5:
. . .
Claims (17)
1. In an athletic shoe for running and other sports involving running, an upper and a bottom, said upper overlying and being attached to a part of said bottom, said bottom com-prising a flexible outsole and a flexible shock-absorbing midsole overlying and secured to said outsole, and said midsole being formed from a foamed polymeric material, the improvement comprising formation means formed separately of said midsole and engaging said midsole along a pre-selected surface area underlying the wearer's foot and located intermediate to the upper and lower surfaces of said midsole for stiffening said midsole along said pre-selected surface area.
2. The athletic shoe defined in claim 1 wherein said formation means underlies at least the wearer's heel, but not the entirety of the wearer's foot, to stiffen said midsole at least in the region underlying the wearer's heel.
3. The athletic shoe defined in claim 2 wherein said formation means extends forwardly from the region underlying the wearer's heel to a location underlying the wearer's medial arch to provide a dynamic arch support for the wearer's medial arch.
4. The athletic shoe defined in claim 1 wherein said formation means spans only the portion of said midsole lying rearwardly of a perimeter which extends inwardly from the medial border of said bottom along a curved path which is proximal to the wearer's first, second and third metatarsal heads, which then curves to extend posteriorly to a section of the midsole underlying the wearer's cuboid, and which is curved along said section to extend laterally to the lateral border of said bottom such that said midsole is stiffened by said for-mation means along the entire region lying rearwardly of said perimeter.
5. The athletic shoe defined in claim 1 wherein said formation means spans the entire section of said midsole underlying the wearer's heel and extends forwardly from said section to underlie the wearer's medial arch but not the wearer's lateral arch or the region of the wearer's foot lying forwardly of his first, second and third metatarsal heads.
6. The athletic shoe defined in claim 1 wherein said upper is of the sliplasted type having a fabric bottom adhered to said midsole, and wherein an insole overlies said fabric bottom within said upper and is formed only from one or more soft, flexible materials.
7. The athletic shoe defined in any one of the preceding claims 1-3 wherein said formation means comprises a stiffening layer lying between and adhered to upper and lower layers of said midsole.
8. The athletic shoe defined in any one of the preceding claims 1-3 comprising an insole, said midsole being at least partially divided into upper and lower layers wherein, said formation means comprises a stiffening layer lying between and adhered to said layers, said upper layer underlying at least the wearer's heel to cushion the heel and said insole being sufficiently pliable to enable said upper layer to compress under the load of the wearer's heel to conform to the configura-tion of the wearer's heel as the wearer's foot strikes the ground during running.
9. The athletic shoe defined in any one of the preceding claims 1-3 wherein said formation means comprises a one-piece, substantially non-stretchable board lying between and adhered to upper and lower layers of said midsole, said board being sufficiently stiff to disperse the forces created by the impact of the wearer's foot on the ground while running and acting on said midsole in the region of said board to provide for a more uniform distribution of the forces acting on said region.
10. The athletic shoe defined in any one of the preceding claims 1-3 wherein said midsole is at least partially divided into upper and lower layers, and wherein said formation means comprises a stiffening board lying between and engaging said layers, said board being at least approximately parallel to said outsole when the outsole is in its straight, unflexed condition, wherein certain forces created by the impact of the wearer's foot on the ground while running act on said midsole in the region of said board, and wherein said board is sufficiently stiff to disperse said forces more uniformly throughout said region, and wherein said board is substantially non-stretchable and is adhered to said upper and lower layers to resist lateral expansion of the midsole under the influence of said forces.
11. In an athletic shoe for running and other sports involving running, an upper and a bottom, said upper overlying and being attached to a part of said bottom, said bottom com-prising a flexible outsole and a flexible shock-absorbing midsole overlying and secured to said outsole, and said midsole being formed from a foamed polymeric materal, the improvement comprising formation means formed separately of said midsole and underlying the wearer's feet and located intermediate to said upper and said midsole for reducing non-uniform degradation of the midsole due to stresses developed in the midsole by the wearer during the course of running.
12. A method of modifying an existing athletic running shoe having a polymeric foamed midsole, comprising the steps of cutting the midsole to provide a formation-receiving space lying between the upper and lower surfaces of the midsole, inserting a stiff formation of pre-selected con-figuration into said space to stiffen the midsole along a pre-selected surface area, and adhering the formation to the midsole.
13. The athletic shoe defined in any one of the preceding claims 4-6 wherein said formation means comprises a stiffening layer lying between and adhered to upper and lower layers of said midsole.
14. The athletic shoe defined in any one of the preceding claims 4-6 comprising an insole, said midsole being at least partially divided into upper and lower layers wherein, said formation means comprises a stiffening layer lying between and adhered to said layers, said upper layer underlying at least the wearer's heel to cushion the heel and said insole being sufficiently pliable to enable said upper layer to compress under the load of the wearer's heel to conform to the configuration of the wearer's heel as the wearer's foot strikes the ground during running.
15. The athletic shoe defined in any one of the preceding claims 4-6 wherein said formation means comprises a one-piece, substantially non-stretchable board lying between and adhered to upper and lower layers of said midsole, said board being sufficiently stiff to disperse the forces created by the impact of the wearer's foot on the ground while running and acting on said midsole in the region of said board to provide for a more uniform distribution of the forces acting on said region.
16. The athletic shoe defined in any one of the preceding claims 4-6 wherein said midsole is at least partially divided into upper and lower layers, and wherein said formation means comprises a stiffening board lying between and engaging said layers, said board being at least approximately parallel to said outsole when the outsole is in its straight, unflexed condition, wherein certain forces created by the impact of the wearer's foot on the ground while running act on said midsole in the region of said board, and wherein said board is sufficiently stiff to disperse said forces more uniformly throughout said region, and wherein said board is substan-tially non-stretchable and is adhered to said upper and lower layers to resist lateral expansion of the midsole under the influence of said forces.
17. For use in an athletic shoe for running and other sports involving running comprising an upper and a bottom, the upper overlying and being attached to a part of the bottom, the bottom comprising a flexible outsole and a flexible shock-absorbing midsole overlying and secured to the outsole, and the midsole being formed from a foamed polymeric material, the improve-ment comprising formation means formed separately of the midsole and adapted to engage the midsole along a preselected surface area underlying the wearer's foot and when in place located intermediate to the upper and lower surfaces of the midsole for stiffening the midsole along the preselected surface area.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US34763282A | 1982-02-10 | 1982-02-10 | |
| US347,632 | 1982-02-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1192739A true CA1192739A (en) | 1985-09-03 |
Family
ID=23364558
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000421200A Expired CA1192739A (en) | 1982-02-10 | 1983-02-09 | Dynamic support system for athletic shoes |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS58165801A (en) |
| KR (1) | KR910001749B1 (en) |
| AU (1) | AU570625B2 (en) |
| BR (1) | BR8300614A (en) |
| CA (1) | CA1192739A (en) |
| DE (1) | DE3304839C2 (en) |
| FR (1) | FR2520986B1 (en) |
| GB (2) | GB2114869B (en) |
| IT (1) | IT1168764B (en) |
| MX (1) | MX158545A (en) |
Families Citing this family (45)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59103605U (en) * | 1982-12-28 | 1984-07-12 | 美津濃株式会社 | athletic shoe soles |
| FR2550424B1 (en) * | 1983-08-10 | 1987-08-14 | Rudy M F | IMPROVED SPORTS SHOE AND ELASTIC STABILIZATION DEVICE FOR SUCH SHOES |
| JPS6060905U (en) * | 1983-10-05 | 1985-04-27 | 西原 浩子 | Mid sole for athletic shoes |
| DE3338557A1 (en) * | 1983-10-24 | 1985-05-02 | Puma-Sportschuhfabriken Rudolf Dassler Kg, 8522 Herzogenaurach | SPORTSHOE WITH A SHOCK ABSORBING OUTSOLE AND METHOD FOR PRODUCING SUCH A SPORTSHOE |
| GB2156654B (en) * | 1984-04-04 | 1987-07-15 | Hi Tec Sports Ltd | Improvements in or relating to running shoes |
| JPS6113902A (en) * | 1984-06-30 | 1986-01-22 | 株式会社アサヒコーポレーション | Athletic shoes |
| DE3629212A1 (en) * | 1986-08-28 | 1988-03-03 | Dassler Puma Sportschuh | MIDSOLE FOR SPORTSHOES |
| US4852275A (en) * | 1986-09-25 | 1989-08-01 | Highland Import Corporation | Shoe having a rigid back part |
| US4905382A (en) * | 1987-02-20 | 1990-03-06 | Autry Industries, Inc. | Custom midsole |
| CA1330485C (en) * | 1986-12-15 | 1994-07-05 | Daniel T. Barry | Shoe with spring-like sole member |
| US4881328A (en) * | 1987-02-20 | 1989-11-21 | Autry Industries, Inc. | Custom midsole |
| US5247742A (en) * | 1987-11-06 | 1993-09-28 | Nike, Inc. | Athletic shoe with pronation rearfoot motion control device |
| US5046267A (en) * | 1987-11-06 | 1991-09-10 | Nike, Inc. | Athletic shoe with pronation control device |
| EP0315340B1 (en) * | 1987-11-06 | 1995-02-15 | Nike International Ltd | Athletic shoe with pronation control device |
| US5185943A (en) * | 1988-07-29 | 1993-02-16 | Avia Group International, Inc. | Athletic shoe having an insert member in the outsole |
| CA1336131C (en) * | 1988-07-29 | 1995-07-04 | Avia Group International, Inc. | Athletic shoe having an insert member |
| US4941273A (en) * | 1988-11-29 | 1990-07-17 | Converse Inc. | Shoe with an artificial tendon system |
| US5255451A (en) * | 1988-12-14 | 1993-10-26 | Avia Group International, Inc. | Insert member for use in an athletic shoe |
| US5218773A (en) * | 1989-01-11 | 1993-06-15 | Stanley Beekman | Torsionally stabilized athletic shoe |
| BR9205669A (en) * | 1991-02-25 | 1994-05-03 | David John Miers | Sports shoe sole |
| US6237251B1 (en) | 1991-08-21 | 2001-05-29 | Reebok International Ltd. | Athletic shoe construction |
| US5319866A (en) * | 1991-08-21 | 1994-06-14 | Reebok International Ltd. | Composite arch member |
| FR2685173B1 (en) * | 1991-12-24 | 1995-04-14 | Salomon Sa | MULTILAYER SPORTSHOE SOLE. |
| WO1996004811A1 (en) * | 1994-08-12 | 1996-02-22 | One Sport, Inc. | Footwear |
| US5611152A (en) * | 1995-03-02 | 1997-03-18 | Converse Inc. | Shoe sole construction containing a composite plate |
| US6205683B1 (en) | 1997-05-30 | 2001-03-27 | The Timberland Company | Shock diffusing, performance-oriented shoes |
| JP3215664B2 (en) | 1998-05-22 | 2001-10-09 | 美津濃株式会社 | Midsole structure for sports shoes |
| US6018891A (en) * | 1998-09-29 | 2000-02-01 | The Rockport Company, Inc. | Shoe construction |
| JP3238132B2 (en) | 1998-10-02 | 2001-12-10 | 美津濃株式会社 | Midsole structure for sports shoes |
| EP1367916A4 (en) * | 2001-02-21 | 2007-03-07 | Bivab Llc | Shoe sole with footbed |
| US20020194747A1 (en) | 2001-06-21 | 2002-12-26 | Passke Joel L. | Footwear with bladder filter |
| US6785985B2 (en) | 2002-07-02 | 2004-09-07 | Reebok International Ltd. | Shoe having an inflatable bladder |
| US8677652B2 (en) | 2002-07-02 | 2014-03-25 | Reebok International Ltd. | Shoe having an inflatable bladder |
| US7622014B2 (en) | 2005-07-01 | 2009-11-24 | Reebok International Ltd. | Method for manufacturing inflatable footwear or bladders for use in inflatable articles |
| HUP0800101A2 (en) * | 2008-02-18 | 2011-11-28 | Laszlo Solymosi | Shoes with unstable sole construction |
| US8316558B2 (en) | 2008-12-16 | 2012-11-27 | Skechers U.S.A., Inc. Ii | Shoe |
| US7877897B2 (en) | 2008-12-16 | 2011-02-01 | Skechers U.S.A., Inc. Ii | Shoe |
| US8572786B2 (en) | 2010-10-12 | 2013-11-05 | Reebok International Limited | Method for manufacturing inflatable bladders for use in footwear and other articles of manufacture |
| US8931187B2 (en) * | 2011-08-25 | 2015-01-13 | Tbl Licensing Llc | Wave technology |
| USD732810S1 (en) | 2013-08-08 | 2015-06-30 | Tbl Licensing Llc | Footwear outsole |
| USD905406S1 (en) | 2018-08-01 | 2020-12-22 | Tbl Licensing Llc | Footwear outsole |
| USD905411S1 (en) | 2018-08-01 | 2020-12-22 | Tbl Licensing Llc | Footwear outsole |
| USD912954S1 (en) | 2018-08-01 | 2021-03-16 | Tbl Licensing Llc | Footwear |
| USD905408S1 (en) | 2018-08-01 | 2020-12-22 | Tbl Licensing Llc | Footwear outsole |
| CN114375166A (en) * | 2019-09-12 | 2022-04-19 | 耐克创新有限合伙公司 | Cushioning element for an article of footwear |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB600613A (en) * | 1944-10-09 | 1948-04-14 | William Mathias Scholl | Improvements relating to sport shoes with arch supporting means |
| GB522866A (en) * | 1938-03-09 | 1940-06-28 | Ernoe Fischer | A sole for footwear |
| US3414988A (en) * | 1965-12-07 | 1968-12-10 | Marbill Company | Shoe having a cushioned insole |
| GB1280792A (en) * | 1971-01-02 | 1972-07-05 | Height Heels Of Leicester Ltd | Improvements in or relating to footwear construction |
| JPS5231083Y2 (en) * | 1973-02-22 | 1977-07-15 | ||
| DE7336712U (en) * | 1973-10-11 | 1974-01-03 | Freudenberg C | Safety boots |
| US4079526A (en) * | 1975-12-27 | 1978-03-21 | Tatsuo Fukuoka | Footwear |
| US4128950A (en) * | 1977-02-07 | 1978-12-12 | Brs, Inc. | Multilayered sole athletic shoe with improved foam mid-sole |
| NL7806461A (en) * | 1977-06-21 | 1978-12-27 | Toho Beslon Co | INSOLE AND METHOD OF MANUFACTURE THEREOF. |
| JPS5450635U (en) * | 1977-09-13 | 1979-04-07 | ||
| AU522809B2 (en) * | 1978-06-26 | 1982-06-24 | Marion F. Rudy | Footwear |
| DE2951572A1 (en) * | 1979-12-21 | 1981-07-02 | Sachs Systemtechnik Gmbh, 8720 Schweinfurt | SHOE WITH ELASTIC OUTSOLE |
| DE3225451A1 (en) * | 1981-07-08 | 1983-02-17 | Stride Rite International, Ltd., Cambridge, Mass. | FOOTWEAR |
-
1983
- 1983-01-06 JP JP58000729A patent/JPS58165801A/en active Granted
- 1983-02-08 BR BR8300614A patent/BR8300614A/en not_active IP Right Cessation
- 1983-02-08 MX MX196200A patent/MX158545A/en unknown
- 1983-02-08 GB GB08303424A patent/GB2114869B/en not_active Expired
- 1983-02-09 CA CA000421200A patent/CA1192739A/en not_active Expired
- 1983-02-09 KR KR1019830000505A patent/KR910001749B1/en not_active IP Right Cessation
- 1983-02-09 IT IT47684/83A patent/IT1168764B/en active
- 1983-02-09 DE DE3304839A patent/DE3304839C2/en not_active Expired - Fee Related
- 1983-02-09 FR FR8302049A patent/FR2520986B1/en not_active Expired
- 1983-02-10 AU AU11302/83A patent/AU570625B2/en not_active Ceased
-
1985
- 1985-03-05 GB GB08505676A patent/GB2156653B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2520986B1 (en) | 1987-08-14 |
| KR840003405A (en) | 1984-09-08 |
| GB2114869A (en) | 1983-09-01 |
| AU1130283A (en) | 1983-08-18 |
| GB2156653A (en) | 1985-10-16 |
| IT8347684A0 (en) | 1983-02-09 |
| GB2114869B (en) | 1986-04-03 |
| FR2520986A1 (en) | 1983-08-12 |
| GB8505676D0 (en) | 1985-04-03 |
| DE3304839A1 (en) | 1983-08-18 |
| JPH0431682B2 (en) | 1992-05-27 |
| BR8300614A (en) | 1983-11-08 |
| JPS58165801A (en) | 1983-09-30 |
| MX158545A (en) | 1989-02-13 |
| GB2156653B (en) | 1986-04-30 |
| IT1168764B (en) | 1987-05-20 |
| AU570625B2 (en) | 1988-03-24 |
| DE3304839C2 (en) | 1995-05-24 |
| GB8303424D0 (en) | 1983-03-16 |
| KR910001749B1 (en) | 1991-03-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |