A sole with an embedded hook, a one-piece injection-molded shoe and a manufacturing method thereof

Abstract

This invention belongs to the field of shoemaking technology and discloses a sole with an embedded shank, a one-piece injection-molded shoe with an integrated upper, and its manufacturing method. The sole with an embedded shank includes: an outsole having an upward-opening receiving cavity; a shank, disposed within the receiving cavity by a supporting structure, with a gap between it and the bottom and inner walls of the receiving cavity; and a midsole filling the receiving cavity and enclosing the shank therein. The one-piece injection-molded shoe with an integrated upper includes a sole and an upper; the sole is as described above, and the bottom of the upper is fixedly connected to an insole. The upper and the insole connected to its bottom are integrally molded with the sole through an injection molding process. This invention, through a unique "pre-positioning of the support component + midsole material encapsulation" structure combined with an injection molding process, successfully solves the technical problems of existing shank installation methods that struggle to balance comfort and support functions, and suffer from insufficient bonding strength. It demonstrates significant technological advancement and practical value.

Description

Technical Field

[0001] This invention belongs to the field of shoemaking technology, specifically relating to an inlaid shank sole, an injection-molded shoe with a continuous upper, and its manufacturing method. Background Technology

[0002] In footwear, the shank is a key component installed in the waist of the shoe (commonly known as the arch). It connects the forefoot and heel, bears the weight of the body, and maintains the stability of the sole. It prevents the sole from bending or collapsing longitudinally in the waist area and is known in the shoemaking industry as the "backbone" of the shoe.

[0003] In existing technologies, the materials used for the shank (or shank) vary, including nylon, steel, and fiberglass. Regarding installation, current technologies typically place the shank above the midsole (i.e., below the insole). Specifically, depending on the assembly process of the upper and sole, the layer between the shank and the foot varies: when using a slip-on design, the shank is located below the midsole fabric, which is a thin layer of fabric or fiber material with limited thickness and weak cushioning; when using a gusseted design, the shank is located below the insole, which, although slightly thicker than the midsole fabric, still cannot effectively cushion the pressure of the hard shank on the foot. Regardless of the process, the shank is close to the foot, separated only by a thin layer of material. When the sole is under stress, the hard shank creates localized hard spots, causing discomfort and pain on the foot. Prolonged wear can lead to foot fatigue and poor comfort.

[0004] In addition, the shank is usually attached to other parts of the sole by adhesive or molding. During long-term dynamic bending, the adhesive layer is prone to aging and failure, which can cause relative displacement or even detachment between the shank and the sole, affecting the lifespan of the shoe. Summary of the Invention

[0005] This invention provides an insole with an embedded shank, an injection-molded shoe with a continuous upper, and a manufacturing method thereof, aiming to solve the technical problems in the prior art where the shank installation method is difficult to balance comfort and support functions, and the bonding firmness is insufficient.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a shoe sole with an embedded shank, comprising: Outsole with an upward-opening receiving cavity; The hook is set in the receiving cavity by a supporting structure and has a gap between it and the bottom wall and inner wall of the receiving cavity; The insole is filled within the receiving cavity and encloses the shank therein.

[0007] As a limitation of the present invention, the support structure includes a plurality of support members, which are spaced apart on the sidewalls on both sides of the accommodating cavity, and each support member extends from the root of the sidewall of the accommodating cavity toward the upper center of the accommodating cavity.

[0008] As a further limitation of the present invention, the support member is made of rubber, and the inclination angle of the support member relative to the bottom wall of the receiving cavity is 45° to 75°.

[0009] As a further limitation of the present invention, the support member and the hook are connected by a snap-fit ​​structure; the snap-fit ​​structure includes a snap-fit ​​portion disposed on the top of the support member, and a snap-fit ​​portion disposed on the hook and cooperating with the snap-fit ​​portion.

[0010] As a further limitation of the present invention, the engaging part is mushroom-shaped or spherical; the engaged part is an assembly hole provided on the hook that is adapted to the engaging part.

[0011] As a further definition of the present invention, the engaging portion is a slot provided on the top of the support member, and the engaged portion is the edge of the hook.

[0012] As another limitation of the present invention, the outsole is a rubber outsole; the insole is a PU insole; The shank has multiple through holes, and the insole passes through the through holes.

[0013] The present invention also discloses a one-piece injection molded shoe with an integrated upper, comprising a sole and an upper; the sole is the aforementioned inlaid shank sole, and the bottom of the upper is fixedly connected to an insole, wherein the upper and the insole connected to the bottom are integrally molded with the sole through an integrated injection molding process.

[0014] The present invention also discloses a method for manufacturing the injection-molded shoe with a continuous upper as described above, comprising the following steps: S1: Provide an outer bottom having an upwardly opening receiving cavity, and a support member is provided on the side wall of the receiving cavity; S2: Provide a hook, install the hook on the support member inside the receiving cavity, so that a gap is formed between the hook and the bottom wall and side wall of the receiving cavity; S3: The shoe last with the upper attached is joined with the bottom mold with the outsole completed in step S2; the bottom of the upper is fixedly connected to the insole; S4: The midsole material is injected into the cavity through an injection process, so that the midsole material fills the cavity and completely covers the shank, and combines with the bottom edge of the upper and the lower surface of the insole. After curing, the midsole is formed, resulting in a shoe product in which the upper and sole are integrally molded.

[0015] As a limitation of the present invention, the shank is provided with a plurality of through holes; in step S4, the injected midsole material passes through the through holes, so that the midsole forms an integral structure on the upper and lower sides of the shank.

[0016] By adopting the above-described technical solution, the beneficial effects achieved by this invention compared to the prior art are as follows: First, it balances comfort and support, completely solving the problem of the shank causing discomfort. The shank is completely encased within the midsole material, forming a cushioning layer of a certain thickness between it and the sole of the foot. The sole directly contacts the soft and elastic midsole material (such as PU), rather than the hard shank. Compared with existing technologies that place the shank on top of the midsole, this invention avoids the hard spots and discomfort caused by the shank as a hard material, while ensuring that the shank, as the "backbone" of the shoe, can properly perform its core functions of connecting the forefoot and heel, bearing the weight of the body, and maintaining the stability of the sole. This prevents the sole from bending or collapsing longitudinally in the waist area, achieving a balance between comfort and support. Secondly, it significantly enhances the torsional control of the sole, ensuring stable wear. In this invention, the shank is suspended and positioned within the receiving cavity by a support member, placing it at a suitable stress point on the sole. When the sole is under stress, the shank can fully exert its torsional resistance, effectively suppressing excessive torsion of the sole during walking, maintaining sole shape stability, and avoiding the risk of instability or even ankle sprains. Simultaneously, the shank is completely covered by the midsole material, forming a composite structure with the midsole material, further enhancing the overall torsional resistance of the sole. Third, the shank and sole are firmly bonded, completely avoiding the problem of adhesive aging. This invention ensures a strong bond between the shank and sole through multiple structures: First, the shank has multiple through holes. During injection molding, the midsole material passes through these through holes, forming a continuous, integrated structure on both sides of the shank, like multiple "anchors" that firmly lock the shank inside the midsole; Second, the midsole material completely covers the shank, forming a comprehensive wrap-around bond. These structures eliminate the need for adhesive bonding between the shank and sole, completely avoiding relative displacement or detachment caused by adhesive aging and failure, significantly extending the shoe's lifespan. Fourth, the snap-fit ​​structure ensures precise shank positioning during the (midsole) injection process, guaranteeing product consistency. In this invention, the support component and the shank are mechanically locked together via a snap-fit ​​structure (such as a mushroom-shaped locking part engaging with the assembly hole). This structure plays a crucial role in the injection process: before and during the injection of the midsole material, the snap-fit ​​structure firmly fixes the shank to the support component. Even under the impact of high-pressure material flow, the shank will not drift, tilt, or fall off, ensuring it remains in the preset suspended position. After the midsole material cures, the shank is completely encased within the midsole, forming a permanent fixation. Therefore, the snap-fit ​​structure ensures the positional accuracy of the shank during the molding process, thereby ensuring consistent shank positioning and stable quality in every pair of shoes.

[0017] In summary, this invention, through its unique "pre-positioning of support components + midsole material covering" structure combined with the injection molding process, successfully solves the technical problems of existing shank installation methods, which struggle to balance comfort and support functions and suffer from insufficient bonding strength. It demonstrates significant technological advancement and practical value. Attached Figure Description

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] Figure 1 This is a three-dimensional structural diagram of the injection-molded shoe with integrated upper in an embodiment of the present invention; Figure 2 This is a longitudinal section diagram of the injection-molded shoe with integrated upper in an embodiment of the present invention; Figure 3 This is a top view schematic diagram of the assembly relationship between the outsole and the shank in an embodiment of the present invention; Figure 4 This is a three-dimensional structural diagram of the hook in an embodiment of the present invention; In the diagram: 1. Outsole; 2. Hook; 3. Midsole; 4. Recess; 5. Support; 6. Assembly hole; 7. Through hole; 8. Insole; 9. Upper. Detailed Implementation

[0020] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and understanding purposes only and are not intended to limit the scope of the invention.

[0021] Example 1: A shoe sole with an embedded shank This embodiment includes an outsole 1, a shank 2, and a midsole 3.

[0022] The outsole 1 is made of abrasion-resistant material and has an upward-opening receiving cavity 4. In this embodiment, the outsole 1 is made of rubber. The shape of the receiving cavity 4 matches the outline of the sole, and its depth is determined according to the sole design requirements, generally in the range of 4 to 15 mm. The receiving cavity 4 is used to accommodate the shank 2 and serves as the molding space for the midsole 3 material.

[0023] The shank 2 is positioned within the receiving cavity 4 via a supporting structure. It is a conventional elongated structure used in shoemaking, extending along the length of the sole. Its shape and size can be adjusted according to the sole design requirements. The shank 2 is made of a material with sufficient rigidity, such as glass fiber composites, carbon fiber composites, nylon, or steel, to ensure it can properly perform its core functions of connecting the forefoot and heel, bearing the weight of the body, and maintaining sole stability. Those skilled in the art should understand that the shank 2 can adopt various conventional shapes known in the art, as long as the above functions are achieved; this invention does not limit its application.

[0024] The midsole 3 is made of a foamable injection moldable material, which is filled into the receiving cavity 4 by injection molding and completely covers the shank 2 therein. The midsole 3 is preferably made of polyurethane (PU) material, but other foamable injection moldable materials such as ethylene-vinyl acetate copolymer (EVA) can also be used.

[0025] like Figure 3 As shown, the support structure includes multiple support members 5. These support members 5 are spaced apart on the sidewalls of the receiving cavity 4 on both sides of the waist area, and each support member 5 extends from the root of the sidewall of the receiving cavity 4 towards the upper center of the receiving cavity 4. Through this arrangement, when the hook 2 is installed on the support member 5, a uniform gap is formed between the hook 2 and the bottom and sidewalls of the receiving cavity 4. This reserves space for the subsequent filling of the midsole 3 material, ensuring that the hook 2 is completely enclosed within the midsole 3 material.

[0026] Preferably, the support member 5 is made of rubber and is integrally molded with the outsole 1. The inclination angle of the support member 5 relative to the bottom wall of the receiving cavity 4 is 45° to 75°, with 60° being optimal. This angle allows the support member 5 to provide stable support for the shank 2 from both sides, while also facilitating the installation and positioning of the shank 2. The length of the support member 5 is set according to the thickness requirements of the midsole 3 in the outsole design, generally 3 to 15 mm, ensuring that the shank 2 is suspended in the central area of ​​the receiving cavity 4, that is, from the widest part of the forefoot to the heel counter. For irregularly shaped shanks 2, it can also extend to the toe area or the end of the heel.

[0027] To ensure that the hook 2 does not drift, tilt, or detach when subjected to high-pressure material flow during injection, the support 5 is connected to the hook 2 via a snap-fit ​​structure. The snap-fit ​​structure has two preferred implementation methods: Method 1: Mushroom head / ball head snap-fit The top of the support member 5 is provided with a locking part, which is a mushroom-shaped or spherical structure, and its maximum diameter is larger than the diameter of the main body of the support member 5. The hook 2 has a corresponding mounting hole 6 that is adapted to the locking part, serving as the locked part.

[0028] During installation, the elasticity of the rubber material is used to press the mushroom-shaped or spherical engaging part into the mounting hole 6. After passing through the mounting hole 6, the engaging part elastically returns to its original position. Since its diameter is larger than the diameter of the mounting hole 6, the hook 2 is thus locked onto the support member 5.

[0029] Method 2: Card slot connection The top of the support member 5 is provided with a slot as a locking part, which is an annular groove surrounding the top of the support member 5. The edge of the hook 2 serves as the locking part.

[0030] During installation, the edge of the hook 2 is inserted into the slot to achieve a fixed connection between the two. This structure can also achieve precise positioning of the hook 2 on the support 5, and is suitable for hooks 2 of different shapes and thicknesses.

[0031] The aforementioned snap-fit ​​structure plays a crucial role in the injection process: before and during the injection of the midsole 3 material, the snap-fit ​​structure firmly fixes the shank 2 to the support 5, ensuring that it always remains in the preset suspended position, thereby ensuring that the position of the shank 2 of each pair of shoes is consistent and the quality is stable.

[0032] To further enhance the bonding strength between the shank 2 and the midsole 3, such as Figure 3 and Figure 4 As shown, the hook 2 is provided with multiple through holes 7. The shape of the through holes 7 can be circular, elliptical, or polygonal. In this embodiment, circular holes are preferred, with a diameter of 2.5 to 5 mm. The through holes 7 are evenly distributed on the hook 2, and their number and distribution are determined according to the size and strength requirements of the hook 2, usually 4 to 8 are provided.

[0033] During injection molding, the midsole 3 material passes through these through-holes 7, forming a continuous, integrated structure on the upper and lower sides of the shank 2. After curing, the midsole 3 material forms an "anchor"-like structure at the through-holes 7, firmly locking the shank 2 inside the midsole 3. This structure eliminates the need for adhesive bonding between the shank 2 and the midsole 3, completely avoiding relative displacement or detachment caused by adhesive aging and failure, significantly extending the shoe's lifespan. Simultaneously, the through-holes 7 also reduce the weight of the shank 2 while ensuring sufficient strength.

[0034] In this embodiment, in addition to rubber, the outsole 1 can also be made of materials with good wear resistance, such as thermoplastic elastomer (TPE) and thermoplastic polyurethane (TPU); in addition to the above materials, the shank 2 can also be made of other materials with sufficient rigidity according to performance requirements; in addition to PU and EVA, the insole 3 can also be made of other foamable injection moldable materials.

[0035] Example 2: A one-piece injection molded shoe with integrated upper like Figure 1 and Figure 2 As shown, this embodiment includes an upper 9 and a sole with an embedded shank 2 as described in Embodiment 1. An insole 8 is sewn to the bottom of the upper 9, and the insole 8 is fixedly connected to the upper 9 as a single unit. The insole 8 is made of a soft material, such as EVA foam sheet, PU foam sheet, latex pad, memory foam, or composite material, to improve wearing comfort.

[0036] The upper 9 and the insole 8 sewn to its bottom are integrally molded with the sole using a single injection molding process. Specifically, during the injection molding process, the midsole 3 material fills the cavity 4 of the outsole 1, completely covering the shank 2, and simultaneously bonding with the bottom edge of the upper 9 and the lower surface of the insole 8. After curing, the midsole 3 and insole 8 are tightly bonded together, forming a complete sole structure. This structure eliminates the need for adhesives between the upper 9 and the sole, completely avoiding the problem of glue separation.

[0037] The upper 9 can be made of any suitable upper material, such as leather, fabric, synthetic leather, etc., depending on the purpose and style of the shoe.

[0038] Example 3: A method for manufacturing a one-piece injection molded shoe with a continuous upper. This embodiment employs a combined injection molding process, integrating the installation of the shank 2 with the molding of the sole and the joining of the upper 9 into one unit. The specific steps are as follows: Step S1: Outsole 1 Preparation An outsole 1 is provided, the outsole 1 having an upwardly opening receiving cavity 4, and a support member 5 is provided on the side wall of the receiving cavity 4. The outsole 1 is preferably prepared by compression molding, and the support member 5 is integrally formed with the outsole 1.

[0039] Step S2: Install the hook 2 A hook 2 is provided and installed on the support 5 inside the receiving cavity 4. During installation, the hook 2 is fixedly connected to the support 5 by a snap-fit ​​structure, creating a gap between the hook 2 and the bottom and side walls of the receiving cavity 4. Specifically: If the mushroom head / ball head snap-fit ​​method is adopted, align the mounting hole 6 on the hook 2 with the snap-fit ​​part on the top of the support 5, apply pressure to make the snap-fit ​​part pass through the mounting hole 6, and after the snap-fit ​​part elastically resets, it snaps into the mounting hole 6 to achieve fixation; If a slot-and-clamp method is used, the edge of the hook 2 is inserted into the slot at the top of the support 5 to achieve fixation.

[0040] At this point, the hook 2 is precisely positioned in the receiving cavity 4, maintaining a uniform gap with the bottom wall and side wall of the receiving cavity 4.

[0041] Step S3: Mold closing The shoe last with the upper 9 attached is joined with the bottom mold containing the outsole 1 (after step S2). The bottom edge of the upper 9 is pre-fixed to the insole 8 (e.g., by stitching or gluing), and the insole 8 is fitted onto the shoe last along with the upper 9. After joining, the insole 8 is located at the opening of the receiving cavity 4, maintaining an appropriate distance from the shank 2 to allow space for the subsequent injection of the midsole 3 material.

[0042] Step S4: Injection Molding The midsole material 3 is injected into the receiving cavity 4 using an injection molding process. In this embodiment, the midsole material 3 is preferably liquid PU raw material, the mold temperature is 40-60℃, and the injection pressure is 100MPa. The midsole material 3 fills the receiving cavity 4 and completely covers the shank 2, while also bonding with the bottom edge of the upper 9.

[0043] If the hook 2 is provided with through holes 7, the material of the insole 3 will pass through these through holes 7 during the filling process, forming a continuous integral structure on the upper and lower sides of the hook 2.

[0044] After injection, foaming and curing occur within the mold. The curing time is typically 5–10 minutes, depending on the formulation and thickness of the midsole 3 material. After curing, the midsole 3 is formed, resulting in a shoe product where the upper 9 and sole are integrally molded.

[0045] This manufacturing method has the following significant advantages: First, the shank 2 is precisely pre-positioned before injection through a snap-fit ​​structure, avoiding the displacement problem that may occur during the molding process of the shank 2 in traditional processes, and ensuring that the position of the shank 2 is consistent in each pair of shoes. Second, during injection molding, the midsole 3 material fills the cavity 4 in one go and is simultaneously bonded to the bottom edge of the upper 9 and the lower surface of the insole 8, achieving the one-piece molding of the upper 9 and the sole without the need for subsequent gluing processes. Third, if the shank 2 has a through hole 7, the "anchor" structure formed by the material of the midsole 3 passing through the through hole 7 further enhances the bonding strength between the shank 2 and the midsole 3. Fourth, the entire process is highly integrated, which simplifies the production process, improves production efficiency, and ensures strong controllability of the quality of finished shoes.

[0046] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A shoe sole with an embedded shank, characterized in that, include: Outsole with an upward-opening receiving cavity; The hook is set in the receiving cavity by a supporting structure and has a gap between it and the bottom wall and inner wall of the receiving cavity; The insole is filled within the receiving cavity and encloses the shank therein.

2. The shoe sole with an embedded shank according to claim 1, characterized in that, The support structure includes multiple support members, which are spaced apart on the side walls of the accommodating cavity on both sides of the waist hollow, and each support member extends from the root of the side wall of the accommodating cavity to the upper center of the accommodating cavity.

3. The shoe sole with an embedded shank according to claim 2, characterized in that, The support is made of rubber, and the angle of inclination of the support relative to the bottom wall of the cavity is 45° to 75°.

4. The shoe sole with an embedded shank according to claim 3, characterized in that, The support member and the hook are connected by a snap-fit ​​structure; the snap-fit ​​structure includes a snap-fit ​​part disposed on the top of the support member and a snap-fit ​​part disposed on the hook and cooperating with the snap-fit ​​part.

5. The shoe sole with an embedded shank according to claim 4, characterized in that, The engaging part is mushroom-shaped or spherical; the engaged part is an assembly hole on the hook that is adapted to the engaging part.

6. The shoe sole with an embedded shank according to claim 4, characterized in that, The engaging part is a slot provided on the top of the support member, and the engaged part is the edge of the hook.

7. A shoe sole with an embedded shank according to any one of claims 1-6, characterized in that, The outsole is a rubber outsole; the insole is a PU insole; The shank has multiple through holes, and the insole passes through the through holes.

8. A one-piece injection molded shoe with an integrated upper, comprising a sole and an upper; characterized in that, The sole is an inlaid shank sole as described in any one of claims 1-7, and the bottom of the upper is fixedly connected to an insole. The upper and the insole connected to its bottom are integrally formed with the sole through a joint injection molding process.

9. A method for manufacturing a one-piece injection molded shoe as described in claim 8, characterized in that, Includes the following steps: S1: Provide an outer bottom having an upwardly opening receiving cavity, and a support member is provided on the side wall of the receiving cavity; S2: Provide a hook, install the hook on the support member inside the receiving cavity, so that a gap is formed between the hook and the bottom wall and side wall of the receiving cavity; S3: The shoe last with the upper attached is joined with the bottom mold with the outsole completed in step S2; the bottom of the upper is fixedly connected to the insole; S4: The midsole material is injected into the cavity through an injection process, so that the midsole material fills the cavity and completely covers the shank, and combines with the bottom edge of the upper and the lower surface of the insole. After curing, the midsole is formed, resulting in a shoe product in which the upper and sole are integrally molded.

10. The method according to claim 9, characterized in that, The shank has multiple through holes; in step S4, the injected midsole material passes through the through holes, so that the midsole forms an integral structure on the upper and lower sides of the shank.

Images