Injection molded and welted footwear and construction method thereof

Information

  • Patent Grant
  • 6763609
  • Patent Number
    6,763,609
  • Date Filed
    Thursday, January 24, 2002
    22 years ago
  • Date Issued
    Tuesday, July 20, 2004
    20 years ago
Abstract
Injection molded welted construction footwear according to the present invention includes a perforated midsole welted to an upper. The perforated midsole permits molten outer sole material to flow through the midsole during the molding process and fill the space between the insole and the midsole and thus sandwich the midsole. This technique forms outer soles to be durably and flexibly attached to the upper without use of traditional adhesives.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention relates to footwear sole construction, and more specifically to sole injection molding for welted construction footwear.




2. Description of the Prior Art




Conventional footwear construction has generally followed two methods, welted construction and molded construction. Welted construction generally stitches an outer sole to an upper to form footwear and thus is labor intensive and therefore expensive. Molded construction generally uses molds and liquid sole material to form the sole onto an upper. This is a less expensive alternative that results in a very durable and flexible outer sole, however the bond between the outer sole and the upper may not be as durable as welted attachment.




Both methods may also attach a midsole to an upper and attach an outer sole thereto using an adhesive. This may be a less expensive alternative, it also produces less satisfactory results.




What is needed is a method that combines the efficiency and durability of molding methods with the quality results of welted construction.




SUMMARY




In a first aspect, the present invention provides a perforated midsole for welting to an upper. The midsole may be made of soft woven or other soft to semi-rigid midsole board material. The perforations enable molten outer sole material to flow above the midsole and thus solidly bind a molded outer sole to an upper without the use of conventional adhesives. This technique results in a flexible footwear with a durable outer sole.




In another aspect, the present invention provides a method of mold forming soles onto welted uppers without the use of conventional adhesives.




In a still further aspect, the present invention provides a die-cut midsole having alternative perforation styles and patterns for a midsole according to the present invention. The different patterns are suitable for different outer sole materials and may also result in different wear characteristics.




These and other features and advantages of this invention will become further apparent from the detailed description and accompanying figures that follow. In the figures and description, numerals indicate the various features of the invention, like numerals referring to like features throughout both the drawings and the description.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a side view of a shoe according to the present invention.





FIG. 2

is a top view of a midsole according to the present invention.





FIG. 3

is a cross section view of the shoe of

FIG. 1

taken along A-A′.





FIG. 4

is a picture of the heel of a welted midsole according to the present invention.





FIG. 5

is a picture of the bottom of a welted midsole using a first material according to the present invention.





FIG. 6

is a picture of the bottom of a welted midsole using a second material according to the present invention.





FIG. 7

is a picture of the toe of a welted midsole according to the present invention.





FIG. 8

is a side view picture of an upper having a welted midsole according to the present invention.





FIG. 9

is a close-up view of the shoe of FIG.


8


.





FIG. 10

is a low angle side view picture of a shoe having a molded outer sole according to the present invention.





FIG. 11

is a picture of a molded outer sole according to the present invention.





FIG. 12

is a picture of an open shoe mold according to the present invention.





FIG. 13

is a picture of an open shoe mold including an upper having a welted midsole according to the present invention.





FIG. 14

is a close-up picture of a mold cover including an upper having a welted midsole.





FIG. 15

is a close-up picture of an outer sole mold bottom.





FIG. 16

is a picture of an outer sole mold bottom being filled with molten sole material.





FIG. 17

is a picture of a closed shoe mold with an upper extending therefrom according to the present invention.





FIG. 18

is a picture of a mold filling apparatus according to the present invention.





FIG. 19

is a picture of a mold conveyor according to the present invention.





FIG. 20

is a picture of a manufacturing facility according to the present invention.





FIG. 21

is a top view of an alternative embodiment of a midsole according to the present invention.





FIG. 22

is a top view of another alternative embodiment of a midsole according to the present invention.











DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION




Referring to

FIG. 1

, a side view of a shoe


10


according to the present invention is shown. The externally visible elements of shoe


10


are upper


12


and outer sole


14


. Upper


12


may be formed from any conventional material such as leather, fabric or synthetic material and may be formed by any conventional method such as lasting. Outer sole


14


may be formed by any conventional molding method using any suitable material. In a currently preferred embodiment of the present invention, outer sole


14


is formed using molten polyurethane.




Referring now to

FIG. 2

, midsole


16


may be welted to upper


12


. Midsole


16


may be composed of any conventional midsole material such as soft woven or other soft to semi rigid midsole board material. Midsole


16


may include perforations


18


. Perforations


18


may be separated into groups such as perforations


20


,


22


and


24


. Perforations such as perforations


18


may be formed by any conventional means during or after the formation of a midsole such as midsole


16


. In a currently preferred embodiment of the present invention, all perforations


18


are circular and are formed by die cutting. In alternative embodiments, edge perforations such as perforations


20


may have different sizes and or shapes than mid perforations such as perforations


22


, or center perforations such as perforations


24


. Perforations such as perforations


18


may be grouped and treated in many different configurations such as heel group


11


and or toe group


13


or arch group


15


as shown in

FIGS. 21 and 22

. The perforations such as perforations


18


may be formed in many different sizes and shapes such as squares


17


, rectangles


19


, chevrons


21


, arcs


23


or any other conventional shape or combination of shapes also as shown in

FIGS. 21 and 22

.




Referring again to

FIG. 2

, inter-perforation spacing


26


may vary between perforations such as perforation


20


A and perforation


20


B, and between perforations such as perforation


22


A and perforation


24


A. Edge perforations such as perforations


20


may be set back away from edge


30


by a space


32


. Space


32


may be the same around the perimeter of midsole


16


as shown or may vary with the location of a perforation around the midsole such that a perforation such as perforation


20


C may be closer or farther from edge


30


than a perforation such as perforation


20


D.




Referring now to

FIG. 3

, the shoe


10


is shown in a cross section view taken along A-A′. Midsole


16


is shown attached to upper


12


using welting strip


34


. Outer sole


14


is shown sandwiching midsole


16


. The material used to form outer sole


14


such as material


40


is permitted to flow through perforations such as perforation


44


and fill space


36


between midsole


16


and insole


38


. A form such as last


37


or other suitable shape may be used in upper


12


to maintain an even distribution of material


40


. Once material


40


has cured or hardened, midsole


16


is inextricably bound within material


40


of outer sole


14


, and thus outer sole


14


is attached to upper


12


without use of conventional adhesive. Selection of material


42


used to form midsole


16


may be done to customize the stiffness of midsole


16


and or to tailor the bonding between midsole


16


and outer sole


14


to customize the flexibility or stiffness characteristics of shoe


10


.




Referring now to

FIG. 4

, footwear such as shoe


50


is shown at an angle to permit viewing midsole


52


from heel


54


. Upper


56


is attached to midsole


52


by welting or stitching


58


or any other suitable method. In a currently preferred embodiment of the present invention a shoe such as shoe


50


is formed on a last. In a first embodiment, midsole


52


is composed of a first material such as material


60


.




Referring now to

FIG. 5

, shoe


62


is shown with a view perpendicular to lower surface


64


of midsole


66


. Midsole


66


is composed of a second alternative material such as material


68


.




Referring now to

FIG. 6

, shoe


50


is shown with a view perpendicular to lower surface


52


L of midsole


52


. A number of perforations such as perforation


70


permit the molten material which forms the outer sole to flow through midsole


52


and sandwich or completely envelope midsole


52


and form a tight midsole to outer sole bond.




Referring now to

FIG. 7

, shoe


50


is shown at an angle to permit viewing midsole


52


from toe


72


. In a first embodiment, midsole


52


is composed of a first material such as material


60


.




Referring now to

FIG. 8

, shoe


50


is shown in a side view with upper


56


attached to midsole


52


using welting strip


74


. Welting strip


74


may be composed of any suitable material such as leather, rubber, or a synthetic material such as polyurethane. According to the present invention, upper


56


may be a mid size, as shown, or a low cut shoe style or a high cut boot style or any other style footwear.




Referring now to

FIG. 9

, shoe


50


is shown in a close-up side view with upper


56


attached to midsole


52


using welting strip


74


. In this view an outer sole such as outer sole


40


of

FIG. 3

has not yet been molded in place. Edge


80


of midsole


52


is clearly visible adjacent welting strip


74


.




Referring now to

FIG. 10

, shoe


50


is shown in a low angle side view showing outer sole


76


formed according to the present invention. After formation of outer sole


76


, edges of midsole


52


such as edge


80


are difficult to distinguish.




Referring now to

FIG. 11

, shoe


50


is shown with a view perpendicular to lower surface


76


L of outer sole


76


. Outer sole


76


may contain any conventional patterns or treads such as tread


78


.




Referring now to

FIG. 12

, a mold such as mold


90


is used to form outer soles such as outer sole


76


according to the present invention. Molds such as mold


90


may be composed of three elements, sole mold


92


, upper mold half


94


and upper mold half


96


. Mold


90


may be made of any suitable material such as steel or aluminum.




Referring now to

FIG. 13

, in a currently preferred embodiment of the present invention, an upper such as upper


56


having a welted midsole such as midsole


52


may be secured between upper mold half


94


and upper mold half


96


. Upper mold half


94


and upper mold half


96


may be secured together in any conventional manner.




Referring now to

FIG. 14

, is a close-up picture of a mold cover enclosing an upper having a welted midsole according to the present invention. In a currently preferred embodiment of the present invention material


98


is a welting strip such as welting strip


74


which is in direct contact with upper mold half


94


and upper mold half


96


. Having material


98


contact upper mold half


94


and upper mold half


96


prevents the material used to form an outer sole from contacting or curing on a welting strip such as welting strip


74


or on an upper such as upper


56


.




Referring now to

FIG. 15

, in a close-up picture of open mold


90


the alignment between outer sole mold


92


and a welted midsole such as midsole


52


may be seen. In use, upper mold half


94


and upper mold half


96


, enclosing a welted upper and midsole such as shoe


50


of

FIG. 8

, pivot on hinges such as hinges


100


thus bringing heel


54


in close proximity to outer sole heel area


102


and toe


72


in close proximity to outer sole toe area


104


. Patterns or treads such as tread


78


of

FIG. 11

may be formed by mold patterns such as pattern


106


.




Referring now to

FIG. 16

, outer sole mold bottom


108


may be filled with molten sole material


110


. Molten sole material


110


may be any suitable natural or synthetic material. In a currently preferred embodiment of the present invention, molten sole material


110


is polyurethane.




Referring now to

FIG. 17

, a shoe mold such as mold


90


may be closed thus forcing molten sole material


110


into contact with a midsole such as midsole


52


. The volume of molten sole material


110


may be sufficient to force molten sole material


110


through perforations such as perforation


70


and cause space


36


to be filled with molten sole material


110


.




Referring now to

FIG. 18

, in a currently preferred embodiment of the present invention a production facility such as production facility


112


may be used to manufacture footwear according to the present invention. Production facility


112


may include one or more sole material dispenser devices such as device


114


, one or more curing devices such as curing device


116


and one or more conveyor devices such as conveyor


118


.




Referring now to

FIG. 19

, a mold conveyor such as conveyor


118


may be used to move molds such as molds


120


-


124


. Sole material dispenser heads


126


and


128


may be used to dispense molten sole material such as molten sole material


110


into molds such as molds


120


-


124


as the molds pass by position


130


on conveyor


118


.




Referring now to

FIG. 20

, after molds are filled and closed, they may be transported to a curing device such as curing device


116


. After molds exit curing device


116


through exit


132


the molds may be opened and finished footwear may be removed at position


134


.




Having now described the invention in accordance with the requirements of the patent statutes, those skilled in this art will understand how to make changes and modifications in the present invention to meet their specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention as set forth in the following claims.



Claims
  • 1. An injection molded and wetted footwear comprising:a. an upper; b. a mid sole having a plurality of perforations, being attached to the upper using one or more welting strips; and c. a molten outer sole being bound to the upper through the perforations on the mid sole; d. said molten outer sole not being in direct contact with the welting strips.
  • 2. The footwear of claim 1 wherein said upper is formed from leather, fabric, or synthetic material.
  • 3. The footwear of claim 1 wherein said molten outer is formed using molten polyurethane.
  • 4. The footwear of claim 1 wherein said perforated mid sole is made of soft to semi-rigid mid sole board material.
  • 5. The footwear of claim 1 wherein said perforations are formed in shapes of squares, rectangles, chevrons, or arcs.
  • 6. The footwear of claim 1 wherein said perforations are circular and are formed by die cutting.
  • 7. The footwear of claim 1 wherein said welting strips are composed of leather, rubber, or polyurethane.
  • 8. The footwear of claim 1 wherein said mid sole is attached to said upper using a stitching through said welting strips.
  • 9. The footwear of claim 1 further comprising:a. an insole, b. a fill space between the mid sole and the insole, and c. a material, wherein said material is permitted to flow through the perforations on said mid sole and fill the fill space, whereupon curing or hardening of said material the mid sole is inextricably bound within said material of the outer sole such that said outer sole is attached to the upper without using a conventional adhesive.
  • 10. The footwear of claim 9, wherein a last is used in said upper to maintain an even distribution of said material.
US Referenced Citations (7)
Number Name Date Kind
3070909 Binder Jan 1963 A
3216033 Nadler Nov 1965 A
4120104 Lasmo Oct 1978 A
5628127 Notzold May 1997 A
5727271 Romanato et al. Mar 1998 A
5732480 Notzold Mar 1998 A
5930917 Pavelescu et al. Aug 1999 A