METHOD FOR PRODUCING A SHOE SOLE

Abstract

A method for producing a shoe sole. To be able to produce the shoe sole in an economical fashion and with easily selectable spring and damping characteristics, the invention has the following steps: a) extruding a plastic hose and feeding the plastic hose into a blow mold; b) blow molding the plastic hose into a sole hollow body, wherein recesses are introduced on mutually opposing walls of the sole hollow body during the blow molding process, such that parts of the walls are brought into contact with one another and form a supporting structure between the mutually opposing walls; c) removing the blow-molded sole hollow body from the blow mold; d) at least partially filling the blow-molded sole hollow body with plastic bodies, wherein the plastic bodies are added through a first opening in the sole hollow body.

Claims

1-15. (canceled)

16. A method for producing a shoe sole, comprising the steps: a) extruding a plastic hose and feeding the plastic hose into a blow mold or injection molding of a plastic blank and feeding the plastic blank into a blow mold; b) blow molding the plastic hose or the plastic blank into a sole hollow body, wherein recesses are introduced on mutually opposing walls of the sole hollow body during the blow molding process, such that parts of the walls are brought into contact with one another and form a supporting structure between the mutually opposing walls; c) removing the blow-molded sole hollow body from the blow mold; d) at least partially, preferably completely, filling the blow-molded sole hollow body with plastic bodies, wherein the plastic bodies are added through a first opening in the sole hollow body.

17. The method according to claim 16, wherein as plastic bodies spheres, ellipsoids or cylinders are used.

18. The method according to claim 17, wherein the dimensions of the single plastic bodies in the three special directions are between 1 mm and 13 mm, preferably between 3 mm and 6 mm.

19. The method according to claim 16, wherein the plastic bodies consist of foamed plastic material.

20. The method according to claim 16, wherein the plastic bodies consist of expanded thermoplastic polyurethane, of expanded thermoplastic elastomer, especially of expanded thermoplastic elastomer based on olefin, and/or of expanded polypropylene.

21. The method according to claim 16, wherein the sole hollow body consists of thermoplastic polyurethane, of thermoplastic elastomer, of polyamide and/or of rubber material.

22. The method according to claim 16, wherein after step d) a sealing, especially a welding, of the first opening occurs.

23. The method according to claim 16, wherein during or after step d) an evacuation of air from the sole hollow body occurs, especially via a second opening which is disposed at a distance from the first opening.

24. The method according to claim 16, wherein the plastic bodies are arranged in the sole hollow body without connection to another.

25. The method according to claim 16, wherein the plastic bodies are arranged in full package and preferably under pressure in the sole hollow body.

26. The method according to claim 16, wherein the production of the supporting structure takes place by creating one of the recesses with the closed end region into one of the walls by means of a first deformation tool and by creating the other recess with the open end region into the other wall by means of a second deformation tool, wherein the closed end region of one of the recesses is designed for entry into the open end of the other recess.

27. The method according to claim 16, wherein prior to closing of the blow mold and carrying out of step b), an insert is placed into the blow mold so that the insert connects with the sole hollow body during the blow molding process.

28. The method according to claim 27, wherein the insert is pre-fabricated by an injection molding process.

29. The method according to claim 27, wherein the insert has a U-shaped design.

30. The method according to claim 27, wherein the insert consists of thermoplastic polyurethane.

Description

[0037] In FIG. 1 the start of the production process of a shoe sole is shown schematically. An extruder 18 plasticizes plastic material and outputs the same via an extrusion head 17 so that a plastic hose 2 is produced which is closed around the whole circumference. When the same is long enough it is placed into a blow mold 3 which consists of two mold halves which are moved against another into the direction of the double arrow and then enclose the plastic hose 2 for blow molding in known manner.

[0038] As already mentioned alternatively an injection molding of a plastic blank can be taken in consideration which is then deformed in the blow mold 3.

[0039] By the blow molding process a sole hollow body 4 (see FIGS. 2 and 3) is produced which provides a reception space in its inner.

[0040] A first deformation tool 13 and a second deformation tool 15 are schematically indicated. Those tools 13, 15 are moved against another in the direction of the arrow when the mold halves of the blow mold 3 are closed. By the tools 13, 15 supporting structures 9 (see FIGS. 2 to 4) are formed into the sole hollow body 4.

[0041] A plurality of tools 13, 15 are provided although in FIG. 1 is shown only one single pair of tools 13, 15.

[0042] As can be seen from FIG. 2 a number of the mentioned supporting structures 9 have been produced presently which are described in detail below. They have the purpose to provide a supporting function at desired locations via the contact area of the foot on the surface of the shoe sole 1 so that at the application of the body weight of the wearer of the shoe the shoe sole 1 does not yield to the side in an uncontrolled manner.

[0043] Details of the supporting structure are apparent from FIG. 4. Here it can be seen that the sole hollow body 4 comprises an upper wall 5 and a bottom wall 6 which are arranged facing another with a distance after carrying out the blow molding process and enclose the mentioned hollow between another. By the deformation tools 13 and 15 recesses 7 and 8 are formed at those locations which are apparent from FIG. 2, namely by the first deformation tool 13 the recess 7 and by the second deformation tool 15 the recess 8.

[0044] As can be seen the recess 7 has a closed end region 14 while the recess 8 has an opening by the second deformation tool 15 which is designed needle-shaped at its axial end. This opening is dimensioned in such a manner that the recess 7 with its closed end region 14 can at least partially enter into the same.

[0045] The supporting structure 9 which is produced in such a manner prevents respectively impedes a relative movement between the upper wall 5 and the bottom wall 6 in horizontal direction (at intended use of the shoe which has the mentioned shoe sole 1).

[0046] When the described sole hollow body 4 is completed insofar the hollow, which is contained in the same, is filled with plastic bodies 10. This is illustrated in FIG. 3. For this a filling nozzle 19 is inserted into an opening 11 in the sole hollow body 4. Then, via the filling nozzle 19 sphere-shaped or ellipsoid plastic bodies 10 made of expanded thermoplastic polyurethane (E-TPU) are filled, as the case may be supported by pressurized air, into the sole hollow body 4 until the same is completely filled with plastic bodies 10. With respect to the material of the plastic bodies 10 hints to respective publications are already given above.

[0047] It is essential that the plastic bodies 10 are filled into the hollow of the sole hollow body 4 quasi as loose material and are placed in the hollow unconnected with another. Accordingly the plastic bodies 10 are free from any connection with another. The plastic bodies 10 indeed stabilize mutually after filling of the sole hollow body 4, but are arranged loosely to another.

[0048] Hereby not only the damping behavior of the sole and thus of the shoe can be influenced very beneficially; also the production process is easy and can be carried out cost-efficiently.

[0049] By the evacuation of air, i. e. by the application of a vacuum at a second opening 12 of the sole hollow body, the filling process can be supported and as the case may be after completion of the same air can be evacuated from the inner of the sole hollow body 4 (see arrow at the opening 12).

[0050] The openings 11 respectively 12 can be closed after completion of the filling process with plastic bodies 10. Here, especially a welding of the openings is taken in consideration. So, a hermitically closed hollow is created in the shoe sole 1 which is filled with the loosely arranged plastic bodies 10.

[0051] In cooperation with the supporting structure 9 the possibility is given to influence the spring and damping behaviors of the shoe sole in a certain range arbitrarily but to take care nevertheless that a good hold for the foot at good stability of the sole is given at the intended use of the shoe which is provided with the shoe sole.

[0052] In FIG. 2 also a preferred embodiment of the described process is illustrated: Here, a U-shaped insert 16 can be seen which is inserted prior to the closing of the blow mold 3 into the cavity of the same. By the blow molding process the insert 16 is firmly connected (welded) with the plastic hose 2 respectively the sole hollow body 4.

[0053] The insert 16 can be used to influence selectively the supporting function of the shoe sole 1. Preferably, the insert 16 is used as heel shell which supports the foot of the user of the shoe which is equipped with the shoe sole in the rear region and namely in the region of the heel.

LIST OF REFERENCES

[0054] 1 Shoe sole

[0055] 2 Plastic hose

[0056] 3 Blow mold

[0057] 4 Sole hollow body

[0058] 5 Wall

[0059] 6 Wall

[0060] 7 Recess

[0061] 8 Recess

[0062] 9 Supporting structure

[0063] 10 Plastic body

[0064] 11 First opening

[0065] 12 Second opening

[0066] 13 First deformation tool

[0067] 14 Closed end region

[0068] 15 Second deformation tool

[0069] 16 Insert

[0070] 17 Extrusion head

[0071] 18 Extruder

[0072] 19 Filling nozzle