Resilient bladder for use in footwear and method of making the bladder

• US 5,993,585 A
• Filed: 01/09/1998
• Issued: 11/30/1999
• Est. Priority Date: 01/09/1998
• Status: Expired due to Term

• Current Assignee: Nike, Inc.
• Original Assignee: Nike, Inc.
• Inventors: Goodwin, David A., Kokstis, Gary Allen, Hogan, Richard M., Buchanan, Steven D. Sr.
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): Tolin, Michael A
• Application Number:
  US09/004,908
• Time in Patent Office: 690 Days
• Field of Search: 156/145, 156/196, 156/245, 156/251, 156/268, 156/274.4, 156/274.8, 156/275.1, 156/285, 156/308.2, 156/308.4, 36/29, 36/35 B, 219/765, 219/766, 428/69, 428/71
• US Class Current: 156/145
• CPC Class Codes: A43B 13/20 Pneumatic soles filled with a compressible fluid, e.g. air, gas inflatable linings for skiboots A43B5/0407
• CPC Class Codes: A43B 21/32 Resilient supports for the heel of the foot
• CPC Class Codes: A43B 7/144 situated under the heel, i.e. the calcaneus bone
• CPC Class Codes: B29C 2791/001 Shaping in several steps
• CPC Class Codes: B29C 2791/006 Using vacuum
• CPC Class Codes: B29C 2791/007 Using fluid under pressure
• CPC Class Codes: B29C 2793/0009 Cutting out
• CPC Class Codes: B29C 51/10 Forming by pressure difference, e.g. vacuum
• CPC Class Codes: B29C 65/00 Joining or sealing of preformed parts , e.g. welding of plastics materials; Apparatus therefor general aspects of processes or apparatus for joining preformed parts B29C66/00; using porous material formed by internal pressure generated therein for joining preformed parts B29C44/1228, B29C44/326
• CPC Class Codes: B29C 65/04 Dielectric heating, e.g. high-frequency welding , i.e. radio frequency welding of plastic materials having dielectric properties, e.g. PVC
• CPC Class Codes: B29C 65/7441 for making welds and cuts of other than simple rectilinear form
• CPC Class Codes: B29C 65/7867 using carriers, provided with holding means, said carriers moving in a closed path
• CPC Class Codes: B29C 66/004 Preventing sticking together, e.g. of some areas of the parts to be joined
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/133 Fin-type joints, the parts to be joined being flexible the parts to be joined being rigid B29C66/1312
• CPC Class Codes: B29C 66/242 said joint lines being closed, i.e. forming closed contours
• CPC Class Codes: B29C 66/3282 for reinforcing the joint
• CPC Class Codes: B29C 66/433 Casing-in, i.e. enclosing an element between two sheets by an outlined seam for bookbinding B42C11/06; for packaging B65B; by laminating B32B37/00; enclosing tubular articles between substantially flat elements B29C66/53261
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/729 Textile or other fibrous material made from plastics
• CPC Class Codes: B29C 66/81415 : being bevelled
• CPC Class Codes: B29C 66/81427 : comprising a single ridge, e.g. for making a weakening line; comprising a single tooth
• CPC Class Codes: B29C 66/81431 : comprising a single cavity, e.g. a groove
• CPC Class Codes: B29C 66/81821 : of the welding jaws
• CPC Class Codes: B29C 66/8322 : Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29C 66/843 : Machines for making separate joints at the same time in different planes; Machines for making separate joints at the same time mounted in parallel or in series
• CPC Class Codes: B29C 66/91411 : of the parts to be joined, e.g. the joining process taking the temperature of the parts to be joined into account
• CPC Class Codes: B29C 66/91421 : of the joining tools
• CPC Class Codes: B29C 66/91431 : the temperature being kept constant over time
• CPC Class Codes: B29C 66/91645 : by steps
• CPC Class Codes: B29C 66/919 : characterised by specific temperature, heat or thermal flux values or ranges specific electrical resistance values B29C66/81262
• CPC Class Codes: B29C 66/91921 : in explicit relation to another temperature, e.g. to the softening temperature or softening point, to the thermal degradation temperature or to the ambient temperature
• CPC Class Codes: B29C 66/91935 : lower than said fusion temperature
• CPC Class Codes: B29C 66/91941 : in explicit relation to Tg, i.e. the glass transition temperature, of the material of one of the parts to be joined
• CPC Class Codes: B29C 66/92445 : by steps
• CPC Class Codes: B29C 66/929 : characterized by specific pressure, force, mechanical power or displacement values or ranges
• CPC Class Codes: B29C 66/949 : characterised by specific time values or ranges
• CPC Class Codes: B29D 35/142 : Soles
• CPC Class Codes: B29D 35/148 : Moulds or apparatus therefor
• CPC Class Codes: B29K 2067/00 : Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2075/00 : Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: B29L 2022/02 : Inflatable articles balls B29L2031/54 ; inner tyres B29L2023/245
• CPC Class Codes: B29L 2031/502 : Heels
• CPC Class Codes: B29L 2031/504 : Soles
• CPC Class Codes: B29L 2031/721 : Vibration dampening equipment, e.g. shock absorbers bumpers B29L2031/3044, springs B29L2031/774
• CPC Class Codes: D04B 21/16 : incorporating synthetic threads
• CPC Class Codes: D10B 2403/0122 : Smooth surfaces, e.g. laminated or coated
• CPC Class Codes: D10B 2403/021 : Lofty fabric with equidistantly spaced front and back plies, e.g. spacer fabrics
• CPC Class Codes: D10B 2501/043 : Footwear
• CPC Class Codes: Y10T 156/1002 : with permanent bending or reshaping or surface deformation of self sustaining lamina
• CPC Class Codes: Y10T 428/231 : Filled with gas other than air; or under vacuum
• CPC Class Codes: Y10T 428/233 : Foamed or expanded material encased

Abstract

The present invention includes a method for forming a resilient bladder structure for use in the sole of footwear. The method comprises the steps of forming a shell from a flexible material to have a floor and a perimeter sidewall extending from the floor; placing a core, having spaced apart outer surfaces connected together by a plurality of connecting members, into the shell within the area bounded by the sidewalls; enclosing the shell and core with a covering sheet; bonding the floor of the shell to one outer surface of the core and the covering sheet to the other outer surface of the core by applying pressure and heat to the shell-core-covering sheet assembly to compress the core during the bonding step; preventing bonding of the sidewall to the covering sheet during the compression of the core; and bonding the covering sheet to an outer edge of the perimeter sidewall of the shell to form a sealed bladder structure; and placing fluid into the interior of the bladder so that the plurality of connecting members are placed under tension.

Claims

1. A method for forming a resilient bladder structure comprising the steps of:

thermoforming a shell from a sheet of plastic material by drawing the sheet to a mold configuration to form a shape having a floor, a perimeter sidewall with a draft angle portion to locate an outer perimeter edge of the sidewall outward of the floor of the shell, and a rim having a flat region extending from the outer perimeter edge of the sidewall;

placing a core, having spaced apart outer fabric layers connected together by plurality of connecting yarns, into the shell within the area bounded by the sidewalls;

enclosing the shell and core with a covering sheet of a plastic material, the covering sheet being sized to extend to at least the flat region and cover the perimeter sidewall and the core placed in the shell;

bonding the floor of the shell to one fabric layer of the core and the covering sheet to the other fabric layer by;

i) applying RF energy with a lamination die to the shell-core-covering sheet assembly;

ii) compressing the core with the lamination die to apply pressure between the shell-core interface and the covering sheet-core interface; and

iii) rolling the sidewall of the shell in on itself during the compression of the core with the lamination die to prevent bonding of the sidewall to the covering sheet during the bonding step;

welding the covering sheet to the outer edge of the sidewall by applying RF energy with a seal die; and

placing fluid into the interior of the bladder so that the plurality of connecting members are placed under tension.

2. The method of claim 1 wherein said bonding step includes heating and applying pressure to the perimeter edge of the shell-core-covering sheet assembly outwardly of the perimeter of the core to ensure application of sufficient energy along the perimeter of the core to form essentially complete bonds between the shell and the core and the covering sheet and the core along the perimeter of the core by extending the perimeter edge of the lamination die outward of the perimeter of the core.

3. The method of claim 2 including preventing the lamination die from drawing thermal energy away from the perimeter of the core by placing an insulating material on the perimeter area of the lamination die which faces the core.

4. The method of claim 2 wherein the step of rolling the sidewall of the shell includes applying pressure with the perimeter edge of the lamination die sufficiently inward of the outer perimeter edge of the sidewall to prevent the lamination die from buckling the sidewall during the compression of the core.

5. The method of claim 1 wherein the thermoforming step includes forming the draft angle sufficiently shallow to prevent the sidewall from flattening during compression of the core to thereby assure rolling in of the sidewall.

6. The method of claim 1 including the step of cooling the shell after thermoforming in a manner sufficient to shrink the shell and bend the perimeter sidewall inwardly to during the shrinkage.

7. The method of claim 6 wherein the thermoforming step includes forming the draft angle sufficiently steep to limit the amount of inward bending of the perimeter sidewall caused by the shrinkage of the shell.

8. The method of claim 5 including the step of cooling the shell after thermoforming in a manner sufficient to shrink the shell and bend the perimeter sidewall inwardly during the shrinkage.

9. The method of claim 8 wherein the thermoforming step includes forming the draft angle sufficiently steep to position the outer perimeter edge of the shell at an aligned location with the seal die after the sidewall of the shell bends inwardly due to shrinkage of the shell after thermoforming.

10. The method of claim 1 wherein said thermoforming step includes coining the flat region by pressing the flat region between a projection on one side of a thermoforming mold and a flat opposite portion of the thermoforming mold to hold the flat region at a substantially uniform thickness during the draw of the thermoforming step.

11. The method of claim 10 including selecting the thickness of the covering sheet to be approximately the same as the uniform thickness of the coined flat region.

12. The method of claim 1 wherein said welding step includes forming both a connected area between the covering sheet and the outer edge of the sidewall of the shell and a tear line along the connected area by applying pressure at periodically increasing pressure levels to the covering sheet with an angled edge of the seal die, and applying RF energy at periodically increasing power levels to melt and connect the material of the covering sheet and shell adjacent to, and on either side of, the angled edge of the seal die, and to form the tear line as a line of thinned out material pressed into the material by the angled edge of the seal die.

13. The method of claim 1 including controlling the amount of compression of the core by stopping the movement of the lamination die compressing the core at a predetermined point.

14. The method of claim 1 wherein said thermoforming step includes forming a floor bevel portion in the perimeter sidewall between the floor and the draft angle portion to reduce thinning of the plastic sheet in the area of the floor bevel portion during draw.

15. The method of claim 1 wherein the step of rolling the sidewall of the shell includes applying pressure to at least portions of the perimeter area of the covering sheet overlying the flat region of the rim of the shell.

16. The method of claim 1 wherein the step of placing fluid into the interior of the bladder includes pressurizing the interior of the bladder with a gas.

17. A method for forming a resilient bladder structure comprising the steps of:

forming a shell from a flexible material to have a floor and a perimeter sidewall and a perimeter edge along the distal end of the perimeter sidewall extending from the floor to define an opening to the shell;

placing a core, having spaced apart outer surfaces connected together by a plurality of connecting members, into the shell within the area bounded by the sidewalls;

enclosing the shell and core with a covering sheet sized to extend to at least the perimeter sidewall of the shell and cover the perimeter sidewall and the core placed in the shell;

bonding the floor of the shell to one outer surface of the core and the covering sheet to the other outer surface of the core by applying pressure and heat to the shell-core-covering sheet assembly to compress the core during the bonding step;

preventing bonding of the sidewall to the covering sheet during the compression of the core;

bonding the covering sheet to an outer edge of the perimeter edge of the shell by applying pressure and heat to the covering sheet and a rim extending outward of the perimeter wall of the shell to connect the covering sheet to the rim of the shell to form a sealed bladder structure; and

placing fluid into the interior of the bladder so that the plurality of connecting members are placed under tension.

18. The method of claim 17 wherein the bonding of the two outer surfaces of the core to the shell and covering sheet occurs prior to and separate from the bonding of the covering sheet to the perimeter edge of the shell.

19. The method of claim 18 wherein the shell is formed by thermoforming a sheet of plastic material into the shape of the shell and cooling the thermoformed shell in a manner sufficient to shrink the shell and bend the perimeter sidewall inwardly during the shrinkage.

20. The method of claim 18 wherein the step of preventing bonding of the sidewall to the covering sheet includes rolling the sidewall in on itself during the compression of the core.

21. The method of claim 20 wherein the step of bonding the outer surfaces of the core to the shell and covering sheet includes heating and applying pressure to the perimeter edge of the shell-core-covering sheet assembly outwardly of the perimeter of the core to ensure application of sufficient energy along the perimeter of the core to form essentially complete bonds between the shell and the core and the covering sheet and the core along the perimeter of the core, and the step of rolling the sidewall of the shell includes applying pressure sufficiently inward of the outer perimeter edge of the sidewall to prevent buckling the sidewall during the compression of the core.

22. The method of claim 21 wherein the thermoforming step includes forming a draft angle between the perimeter sidewall and the floor that is sufficiently shallow to prevent the sidewall from flattening during compression of the core to thereby ensure rolling in of the sidewall, while also forming the draft angle sufficiently steep to position the outer perimeter edge of the shell at an aligned location with a sealing tool after the sidewall of the shell bends inwardly due to shrinkage of the shell after thermoforming.

23. The method of claim 17 wherein the step of placing a fluid into the interior of the bladder includes pressurizing the interior of the bladder with a gas.

24. A method of forming a bladder from first and second sheets of plastic material comprising the steps of:

forming a perimeter seal between the first and second sheets of plastic material to define a sealed chamber and forming a tear line along the perimeter seal by;

i) applying pressure, at periodically increasing pressure levels, with a welding die having an angled edge along the area of the perimeter seal being formed; and

ii) applying RF energy, at periodically increasing energy levels, through the welding die along the area of the perimeter seal being formed

to melt and connect the first and second sheets of plastic material adjacent to, and on either side of, the angled edge of the welding die, and to form the tear line as a line of thinned out material pressed into the material by the angled edge of the welding die; and

forming at least one connection between the first and second sheets of plastic material within the area of the sealed chamber.