Patent Publication Number: US-2022211138-A1

Title: Method for making sole structure with knitted fabric and sole structure

Description:
CROSS REFERENCE TO RELAED APPLICATIONS 
     The present application is a divisional application of U.S. patent application Ser. No. 17/093,156, which was filed on Nov. 9, 2020, for which priority is claimed under 35 U.S.C. § 120, and this application claims priority of Application No. 108141747 filed in Taiwan on Nov. 18, 2019 under 35 U.S.C. § 119, the entire contents of all of which are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a method for making a sole structure, and more particularly to a method for making a sole structure with a knitted fabric and a sole structure. 
     BACKGROUND OF THE INVENTION 
     A shoe is nothing more than composing of an upper and a sole combined with the upper. For the upper, it was formed by splicing multiple sheets of material in the early days. However, some manufacturers have introduced a technical solution to make the upper with knitted fabric, so that the upper is no longer restricted by the material of the sheets, and complex color patterns can be realized by the knitted fabric. 
     However, for the sole, a compressible elastomer is still commonly used as the main implementation. As disclosed in U.S. Pat. Nos. 9,950,486, 10,051,915, and 10,238,172, the compressible elastomer is generally made to have only a single color or monotonous pattern change. In addition, although some manufacturers have introduced a technical solution for forming the sole with a plurality of compressible elastomers, as disclosed in U.S. Pat. Nos. 10,172,415 and 10,166,734, the sole presents color changing with a sense of design by making the compressible elastomers with different colors, but this implementation can still only present visual experience of large-scale color block changes, and cannot present a more unique visual experience or patterns with fine changes. 
     In addition, U.S. Pat. No. 9,848,673 discloses an implementation different from the above-mentioned techniques. In the process of forming the upper, an insert element  300  ( FIG. 11  of U.S. Pat. No. 9,848,673) is added, and a knitted jacket is placed on the insert element and a mold of the upper to form the integral upper and sole, and then a shoe cover element  1800  ( FIG. 18  of U.S. Pat. No. 9,848,673) or an outsole covering component  2400  ( FIG. 24  of U.S. Pat. No. 9,848,673) is correspondingly disposed. However, although this implementation allows the shoe to present a visual experience of fine changes as a whole through the knitted fabric, the shoe is not visually pleasing or attractive and is monotonous. Since the upper and the sole are made of a single knitted fabric, if a user wears the shoe to do vigorous exercise, the knitted fabric corresponding to the upper will pull the knitted fabric corresponding to the sole, causing the knitted fabric corresponding to the sole to detach from the insert element easily, which can easily cause damage to the shoe. 
     In addition, the U.S. Pat. No. 9,775,401 discloses that the sole includes a one-piece woven outsole formed by the knitted fabric  112  ( FIG. 24  of U.S. Pat. No. 9,775,401). The embodiments disclosed in  FIGS. 13-24  and the corresponding paragraphs of the patent U.S. Pat. No. 9,775,401 show that when the one-piece woven outsole is developed, the knitted fabric is first placed in a mold, the knitted fabric is then pressed to form a plurality of concave parts. During pressing the knitted fabric to form the concave parts, a material is injected into each of the concave parts to form a protrusion. However, it can be known from the foregoing that the one-piece knitted outsole described in the embodiments does not have the compressible elastomer as a buffer, which can only be used as one of the components for composing the sole, commonly known as an outsole in the industry, but fail to be qualified as the sole referred in the present invention. 
     SUMMARY OF THE INVENTION 
     A main object of the invention is to solve the problem that the existing methods are incapable of making a sole structure with a compressible elastomer by using a knitted fabric. 
     In order to achieve the above object, the invention provides a method for making a sole structure with a knitted fabric, the method comprises steps of: 
     placing a thermoplastic filling material in the knitted fabric, wherein the knitted fabric comprises a space for the thermoplastic filling material to be placed in and an opening communicating with the space; 
     sealing the opening; and 
     placing the knitted fabric with the opening sealed into a mold, applying a heating temperature to melt the thermoplastic filling material of the knitted fabric, and restricting a shape of the knitted fabric via the mold to make the sole structure, wherein the sole structure includes a compressible elastomer and a knitting texture wrapped around the compressible elastomer and fused with a surface of the compressible elastomer, the compressible elastomer is formed from the thermoplastic filling material after being melted and cooled , the knitting texture is formed from the knitted fabric and is directly observed from an appearance of the sole structure. 
     In one embodiment, the mold includes at least one first mold to define a size of the sole structure, and a second mold matching with the first mold to form a side of the sole structure which is assembled with a shoe upper. 
     In one embodiment, a side of the second mold facing the knitted fabric comprises a continuous curved surface that simulates shape of a sole of a human foot. 
     In one embodiment, the second mold is a shoe last. 
     In one embodiment, the method further includes: performing a trimming operation to the sole structure. 
     In one embodiment, the method further includes: defining the sole structure as a midsole, and sticking an outsole under the sole structure. 
     In one embodiment, the method further includes: placing a thermoplastic material in the mold while the knitted fabric is placed in the mold, wherein the thermoplastic material directly fuses with the sole structure and forms as the outsole when the sole structure is manufactured. 
     In one embodiment, the thermoplastic material and the thermoplastic filling material are a plurality of thermoplastic polyurethane (TPU) expanded particles, and the thermoplastic material and the thermoplastic filling material are melted by a microwave heating method. 
     In one embodiment, the knitted fabric comprises a plurality of yarn loops, and the plurality of yarn loops is knitted by at least one yarn and at least one hot melt yarn. 
     In addition to the aforementioned method, the invention also provides a sole structure, which is made with a knitted fabric, takes a compressible elastomer as a base. The sole structure comprises a knitting texture fused with a surface of the compressible elastomer to wrap around the compressible elastomer while the compressible elastomer is formed, wherein the knitting texture comprises a plurality of yarn loops. 
     In one embodiment, the sole structure comprises an outsole provided on one side of the sole structure. 
     In one embodiment, the compressible elastomer and the outsole are respectively formed from a plurality of thermoplastic polyurethane expanded particles after heated by a microwave heating method. 
     According to the foregoing description, compared with the prior art, the invention has the following features: the sole structure of the invention is an independent part of shoemaking, and the knitting texture located on a surface of the sole structure can also be made of yarns with different colors and be designed with a variety of patterns, so that design ideas of a shoe designer are no longer restricted by the conventional structure. Furthermore, the knitting texture on the surface of the sole structure of the invention can not only provide different colors or patterns of an appearance of the sole for consumers to choose, but also strengthen a structural strength of the compressible elastomer and reduce an incidence of damages of the compressible elastomer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural diagram of a sole structure of a first embodiment of the invention; 
         FIG. 2  is a flowchart of a method of the first embodiment of the invention; 
         FIG. 3  is a first schematic diagram of implementation of the first embodiment of the invention; 
         FIG. 4  is a second schematic diagram of implementation of the first embodiment of the invention; 
         FIG. 5  is a third schematic diagram of implementation of the first embodiment of the invention; 
         FIG. 6  is a fourth schematic diagram of implementation of the first embodiment of the invention; 
         FIG. 7  is a schematic diagram of implementation of a second embodiment of the invention; 
         FIG. 8  is a flowchart of the method of a third embodiment of the invention; 
         FIG. 9  is a schematic diagram of implementation of the third embodiment of the invention; 
         FIG. 10  is a flowchart of the method of a fourth embodiment of the invention; 
         FIG. 11  is a schematic diagram of implementation of the fourth embodiment of the invention; 
         FIG. 12  is a flowchart of implementation of a fifth embodiment of the invention; and 
         FIG. 13  is a top view of the sole structure of a sixth embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The detailed description and technical content of the invention are described below with reference to the drawings. 
     Please refer to  FIG. 1 ,  FIG. 2 , and  FIG. 3 , the invention provides a method  10  for making a sole structure with a knitted fabric. A knitted fabric  20  referred to herein is formed with a space  201  and an opening  202  communicating with the space  201 . Further, the knitted fabric  20  can be implemented by a sock blank (as shown in  FIG. 3 ), a fabric knitted by a bag knitting technique, or a fabric stitched with a plurality of cloth materials. In addition, the knitted fabric  20  of the invention is not used as a basis for forming a sole structure  30 , and a basis of the sole structure  30  is realized with a compressible elastomer  31 . Further, the method  10  includes the following steps of: 
     step  11 : placing a thermoplastic filling material  21  in the space  201  of the knitted fabric  20 ; 
     step  12 : sealing the opening  202 ; and 
     step  13 : placing the knitted fabric  20  with the opening  202  sealed into a mold  40  (as shown in  FIG. 6 ), applying a heating temperature to melt the thermoplastic filling material  21  of the knitted fabric  20 , and restricting a shape of the knitted fabric  20  via the mold  40  to make the sole structure  30 . 
     At the beginning of implementation, the knitted fabric  20  and the thermoplastic filling material  21  are prepared. In one embodiment, the thermoplastic filling material  21  is a plurality of thermoplastic polyurethane (TPU) expanded particles. Please refer to  FIG. 4 , the thermoplastic filling material  21  is placed in the space  201 , and the amount of the thermoplastic filling material  21  filled into the space  201  can be determined according to requirements, and is not limited to be fully filled the space  201 . Thereafter, the opening  202  of the knitted fabric  20  is sealed at a sealing position  203  (shown in  FIG. 5 ) by a processing method such as sewing or hot pressing, so that the thermoplastic filling material  21  is confined in the space  201 . Please also refer to  FIG. 6 . Then, the knitted fabric  20  manufactured by the aforementioned operations is placed in the mold  40 . In one embodiment, the mold  40  includes a first mold  401  and a second mold  402  matching with the first mold  401 . The first mold  401  can be a single mold base or a plurality of sub-mold bases. However, regardless of structures of the first mold  401 , the first mold  401  is formed with a mold cavity  403 . A size of the mold cavity  403  determines a size of the sole structure  30 , that is, the mold cavity  403  is provided for the knitted fabric  20  which is filled and sealed to be placed therein. In general, the sole structure  30  is not only formed in a single size for shoemaking; in other words, it needs to develop multiple sizes in response to market demands. Therefore, the first mold  401  is selected according to the size of the sole structure  30  to be made. In addition, the second mold  402  is used to form a side of the sole structure  30  for assembling with a shoe upper (not shown in the figures), wherein the shoe upper is ordinary skills in the art and will not be repeated here. The second mold  402  is formed with a continuous curved surface  404  thereon that simulates shape of a sole of a human foot. Further, viewed from a side of the continuous curved surface  404 , a lowest point  405  is defined, and based on the lowest point  405 , a forefoot curved surface  406  extends in one direction, and a hindfoot curved surface  407  extends toward an opposite direction of the forefoot curved surface  406 . The forefoot curved surface  406  and the hindfoot curved surface  407  have different shapes. Furthermore, after the first mold  401  and the second mold  402  are disposed correspondingly, the continuous curved surface  404  faces the mold cavity  403  and contacts the knitted fabric  20  placed in the mold cavity  403  to limit shape of the knitted fabric  20  on one side. Specifically, the first mold  401  presses the knitted fabric  20  to form a side of the sole structure  30  facing a sole of a human foot. In addition, in one embodiment, the second mold  402  is directly implemented as a shoe last  408 , and the continuous curved surface  404  is a bottom surface of the shoe last  408 , as shown in  FIG. 7 . 
     After the mold  40  is prepared, the knitted fabric  20  is heated and pressed by the mold  40 . The mold  40  is controlled to apply a heating temperature to the knitted fabric  20 , wherein the heating temperature is sufficient to cause the thermoplastic filling material  21  to melt. In one embodiment, the mold  40  is implemented by microwave heating. In addition, when the thermoplastic filling material  21  is melted, the knitted fabric  20  will be bonded to the thermoplastic filling material  21 . After the mold  40  is demolded and cooled, the sole structure  30  of the invention is formed. Further, the thermoplastic filling material  21  is fused to become the compressible elastomer  31  after being melted and cooled, and texture on the knitted fabric  20  is fused with the thermoplastic filling material  21  when the thermoplastic filling material  21  is melted. That is, after the method of the invention is completed, the sole structure  30  comprises a knitting texture  32  wrapped around the compressible elastomer  31  and fused with a surface of the compressible elastomer  31 . The knitting texture  32  comprises a plurality of yarn loops  22  which is an ordinary skill in the field of knitting technique and will not be described herein. The plurality of yarn loops  22  is formed as the structure of the knitted fabric  20 . Furthermore, the knitting texture  32  of the invention can be directly observed from an appearance of the sole structure  30 , that is, the sole structure  30  as a whole is rendered with colors by the knitting texture  32 . For example, if the knitted fabric  20  with camouflage patterns is used for manufacturing the sole structure  30 , an appearance of the sole structure  30  will be camouflage patterns. In this way, the sole structure  30  of the invention is not limited to a color of the compressible elastomer  31 , but can exhibit a variety of colors and patterns by the knitting texture  32 . In addition, the knitting texture  32  increases the structural strength of the compressible elastomer  31  and reduces a possibility of damage to the compressible elastomer  31  due to multiple deformations and other factors since the knitting texture  32  is wrapped around the compressible elastomer  31  and fused with the surface of the compressible elastomer  31 . 
     It can be known from the foregoing that the knitted fabric  20  of the invention is composed of the plurality of yarn loops  22 , wherein the plurality of yarn loops  22  can be knitted by a single yarn  221  or a plurality of the yarns  221 . In one embodiment, the plurality of yarn loops  22  is knitted by at least one yarn  221  and at least one hot melt yarn  222 , as shown in  FIG. 3 . Accordingly, at the same time that the thermoplastic filling material  21  is melted, the hot melt yarn  222  is also melted and fused with the thermoplastic filling material  21 . After the sole structure  30  is made, only the yarn loops  22  formed by the yarns  221  can be seen in the knitting texture  32 . In addition, there are many implementations of the hot melt yarn  222  referred to herein. In one embodiment, the hot melt yarn  222  is made of a thermofusible material. In another embodiment, the hot melt yarn  222  is composed of a basis yarn and a hot melt layer wrapped around the basis yarn. 
     Please refer to  FIG. 8  and  FIG. 9 , in one embodiment, the sole structure  30  is a structure with an outsole  33  and a midsole; but in other embodiment, the sole structure  30  is limited to with a midsole only. Namely, if the sole structure  30  only with a midsole is manufactured, the sole structure  30  needs to be assembled with the outsole  33  through an additional processing. In one embodiment, the method  10  further includes step  14 : sticking the outsole  33  under the sole structure  30 . In another embodiment, the outsole  33  is formed during the process of preparing the sole structure  30 . Please refer to  FIG. 10  and  FIG. 11 , the method  10  further includes step  15 : placing a thermoplastic material  23  in the mold  40  while the knitted fabric  20  is placed in the mold  40 , wherein the thermoplastic material  23  directly fuses with the sole structure  30  and forms as the outsole  33  when the sole structure  30  is manufactured. A timing of placing the thermoplastic material  23  depends on different designs of the mold  40 , that is, a placement order can be adjusted as follow: placing the thermoplastic material  23  first and then placing the knitted fabric  20 ; or placing the knitted fabric  20  first and then placing the thermoplastic material  23 . In one embodiment, the thermoplastic material  23  is a plurality of thermoplastic polyurethane expanded particles. Therefore, when the mold  40  is heated and presses the knitted fabric  20 , the thermoplastic material  23  is melted simultaneously and fused with one side of the knitted fabric  20 . After the mold  40  is demolded and cooled, the sole structure  30  including the outsole  33  is formed. In one embodiment, the thermoplastic material  23  is melted by microwave heating. 
     Please refer to  FIG. 12 . In one embodiment, after the sole structure  30  is manufactured, the method  10  further comprises step  16 : performing a trimming operation to the sole structure  30 . The trimming operation is implemented by automated machinery or manually. An object of the trimming operation is to trim edges of the knitted fabric  20  remaining after sealing. On the other hand, a position of the sealing position  203  can be adjusted while sealing the opening  202 . In order to avoid damaging an appearance of the sole structure  30 , the sealing position  203  is adjusted to be located at a side of the knitted fabric  20  which is intended to be assembled with an upper (not shown in the figure). In one embodiment, the sealing position  203  is located at a middle section of the sole structure  30 , as shown in  FIG. 13 . Thereby, a complexity of the trimming operation is simplified.