footwear

Abstract

The smooth outer contour of the shape-retaining member maintains the appearance, and the slide section guides attachment and detachment, while the protruding and extended sections provide retention, resulting in a hands-free shoe with superior aesthetics. [Solution] To prevent the appearance from being compromised by the curved heel structure of conventional hands-free shoes, the present invention provides a shape-retaining member in the heel composed of multiple curved surfaces with different radii of curvature. This member is integrally molded from resin material using an alloy mold and includes a slide portion, a support portion, an extension portion, and a convex portion. The convex portion and the center of the support portion form a roughly T-shaped support keel, and the extension portion has a thickness that can accommodate injection molding.

Description

Technical Field

[0001] The present invention relates to the field of shoemaking technology, particularly to hands-free shoes.

Background Art

[0002] In recent years, footwear (including sneakers, casual shoes, formal shoes, etc.) equipped with a hands-free function that can be worn without using hands and without bending while standing is becoming increasingly popular. In this type of footwear, in order to smoothly slide the heel of the foot into the heel part of the footwear, a "sliding table-shaped warp structure" with the upper end of the heel part inclined backward and upward is generally adopted. However, this structure causes a problem of impairing the aesthetic beauty of the appearance.

[0003] Particularly for formal shoes worn in business scenes or official occasions, the flatness of the upper part, the well-shaped silhouette of the shoe, and the refined aesthetic beauty are extremely important requirements. However, in various footwear including formal shoes, heel cups and reinforcing members that have conventionally been used to assist in putting on and taking off shoes at the heel part often have structures where their upper edge parts and side edge parts are explicitly exposed outside the footwear. Therefore, in the case of formal shoes, not only does it disrupt the silhouette and damage the appearance, but there is also a common problem of impairing the unity and aesthetic beauty of the appearance in line with the design intention in other footwear such as sneakers and casual shoes.

[0004] Firstly, heel counters are expensive, secondly, difficult to install, and thirdly, their monotonous appearance makes them incapable of meeting the diverse needs of consumers. In recent years, technologies have emerged, such as JP 2024-116124, JP 2022-139151, JP 2024-128061, and Patent No. 7569114, that attach heel counters to the heels of footwear. These allow the heel to slide more smoothly into the shoe. Formal shoes, in particular, require a flat appearance and refined aesthetics to meet the strict requirements of business settings, but for other types of footwear, "inconspicuous structure" and "consistent appearance" are also important requirements depending on the application and design concept. Traditionally, reinforcing members and heel cups have been installed on the heels of various types of footwear to improve ease of putting on and taking off, but these members have a common problem: due to their structure, outward curvature and exposed edges are unavoidable, resulting in a decrease in the overall appearance quality of the footwear.

[0005] In other words, a common challenge for all footwear with hands-free functionality (including formal shoes) is to achieve both "ease of putting on and taking off" and "flatness and aesthetic appeal in appearance." While this challenge is particularly pronounced in formal shoes, a similar demand exists for other types of footwear as well.

[0006] The heel cup disclosed in Patent Document 1 has a complex S-shaped contour when viewed from the side, and in particular, its upper edge is structured to curve upward and backward. As a result, it is easily visible as a noticeable curve when viewed from the outside of the shoe, which disrupts the simple and upright silhouette required for footwear such as formal shoes. Furthermore, because the heel cup is thin in the central part and thicker around the edges, especially the inner and outer edges, its contour protrudes from beneath the shoe's upper material after molding, which also detracts from its aesthetic appeal.

[0007] The heel counter disclosed in Patent Document 2 is characterized by a shape in which the apex of its arch portion extends in an arc upward and diagonally backward. Due to this structure, the upper end of the heel portion of a shoe molded using this heel counter inevitably curves upward and backward. Furthermore, when downward pressure is applied to the tray portion of the heel counter, the tray portion deforms in a curved manner, which is transmitted to the outer leather upper material, causing unnatural bending of the upper material and making it prone to wrinkles. This presented a technical problem.

[0008] The crescent-shaped core disclosed in Patent Document 3 has a shape in which the upper rear end of its upper portion is curved backward in the front-to-back direction of the footwear. Due to this structural feature, when viewed from the outside of the shoe, this curved portion is easily visible as a conspicuous protrusion. Furthermore, the crescent-shaped core has a roughly inverted triangular shape, with a narrow lower part and a small support base. This shape is thought to be unable to provide sufficient support rigidity against repeated stepping loads and stresses during putting on and taking off, and is considered to have problems with structural stability and durability in long-term use.

[0009] Conventional shaping materials such as chemical sheets and hot melt adhesives provide short-term support and shaping effects, but they lack an active structure that actively assists in tool-free attachment and detachment. Furthermore, these materials have fundamental durability issues, as they are susceptible to material aging over time and fatigue from repeated foot-pressure loads, making them prone to collapse and deformation without being able to maintain their original shape. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] International Publication No. 2023 / 064568 [Patent Document 2] Utility Model Registration No. 3246100 Publication [Patent Document 3] Patent No. 7523103 [Overview of the initiative] [Problems that the invention aims to solve]

[0011] While conventional hands-free shoe technology offers a certain degree of ease of putting on and taking off, its structure often compromises the refined silhouette and flat appearance required for formal footwear, making it difficult to achieve both aesthetic quality and practical performance. Therefore, shoemakers need manufacturing technology that provides hands-free functionality while maintaining a superior appearance, and consumers strongly desire products that offer comfortable and convenient on-and-off functionality while maintaining a level of sophistication appropriate for specific occasions. [Means for solving the problem]

[0012] To address the aesthetic challenges and practical shortcomings of conventional hands-free shoes as described above, the present invention provides footwear equipped with a novel shape-retaining member. Footwear typically includes components such as an opening, upper, forefoot, heel, insole, midsole, and outsole, but the present invention does not require complex modifications to these basic structures. Instead, by incorporating a shape-retaining member composed of curved surfaces with multiple different radii of curvature in the heel, hands-free (tool-free on / off) functionality is achieved without compromising aesthetic appearance.

[0013] In some embodiments of the present invention, the footwear of the present invention has an upper made of leather or fabric, and a shape-retaining member in the heel portion, which is composed of multiple curved surfaces having different radii of curvature. The shape-retaining member is formed by integral molding of a resin material using an alloy mold, and possesses excellent support and flexibility. The shape-retaining member has a slide portion, a support portion, an extension portion, and a protrusion projecting toward the toe at the lower part of the slide portion. In a side view, the surface of the slide portion facing the foot is inclined diagonally backward, and in a plan view, both sides are inclined downward in an arc shape, forming a guide structure for sliding the heel of the foot into the footwear.

[0014] Preferably, both the inner and outer sides of the slide portion extend diagonally forward of the shoe, forming two wing portions, and the angle at which the extensions of the two wing portions intersect is acute.

[0015] Preferably, in a right side view, the extending portion bulges rightward, and in a bottom view, both sides are arcuate and inclined upward, forming a shape that fits the heel of the foot.

[0016] Preferably, in a side view, at least a part of the convex portion protrudes most forward with respect to other parts of the shape retention member.

[0017] Preferably, in a side view, the convex portion, the support portion, and the extending portion form a shape that fits the heel of the foot.

[0018] Preferably, in a front view, the upper part of the shape retention member is arcuate, and both side edges of the upper part have a shape that gradually widens obliquely downward from the slide table portion to the extending portion.

[0019] Preferably, in a side cross-section, the shape retention member does not have a prominent concave-convex shape at the rear, its rear contour line is smooth, and it extends in a single direction or substantially linearly from the upper end to the lower end.

[0020] Preferably, the interior material incorporating the convex portion bulges in the toe direction to form a raised portion, and in a side cross-sectional view, the most protruding point of the raised portion in the toe direction protrudes most forward.

[0021] Preferably, at least a part of the thickness of the convex portion is the thickest compared to other parts of the shape retention member.

[0022] Preferably, the thickness of the convex portion gradually thins across the support portion to the edge of the extending portion.

[0023] Preferably, an end that can be drawn with a single line is formed at the edge of the extending portion.

[0024] Preferably, in order to fit various standard lasts on the extending portion, it has one or more hollow portions (notches).

[0025] Preferably, the central region of the support portion is the thickest, gradually becomes thinner toward the edge region, and an end that can be drawn with a single line is formed at the end of the edge.

[0026] Furthermore, the convex portion and the central region of the support portion constitute a support keel of a substantially T-shaped structure of the support member, the convex portion constitutes a transverse portion of the substantially T-shaped structure, and the central region of the support portion constitutes a longitudinal portion of the substantially T-shaped structure.

[0027] Preferably, the shaping member is integrated and strengthened by a shaping material such as a chemical sheet or hot melt.

[0028] Preferably, a sewing portion is provided at the upper end portion of the heel portion, and it has a structure for fixing the shaping member to the upper end of the heel portion.

[0029] Preferably, the extending portion has a thickness that enables sealing between the mold and the sole mold in the injection manufacturing method.

[0030] Preferably, the convex portion forms a raised structure when the footwear is worn, fits the heel of the foot, and makes it difficult to slip off.

[0031] Preferably, the width of the opening of the heel portion is formed to be smaller than the horizontal width of the heel of the human body, and the radius of curvature of the shape formed by the opening inside the footwear is set to be smaller than the natural radius of curvature of the heel of the human body.

[0032] Preferably, the method of attaching the shaping member is simple and does not require a complicated wrapping process for the heel portion. In the manufacturing process, the sewing portion on the upper part of the shaping member is fixed to the upper end portion of the heel portion by machine sewing or hand sewing, and in the subsequent turning process, the extending portion of the shaping member is sewn together with the upper material and the back material to firmly attach the shaping member to the heel portion.

[0033] Preferably, the lower part of the shape-retaining member is reinforced with a shape-retaining material such as a chemical sheet (a chemically treated sheet material) or hot melt (a material that functions as an adhesive when heated) to ensure the stability of the shape and support capacity of the shape-retaining member, and at the same time, the lower part of the shape-retaining member is sewn to the lower part of the heel of the upper material to further fix its position.

[0034] Preferably, the form-retaining member is made of a resin material that has support strength and elasticity, such as a new high-elasticity material such as TPU, TPE, or TPEE, which has good elasticity and toughness characteristics, can provide sufficient support strength, and further has advantages such as wear resistance, durability, and high temperature resistance, ensuring the sustainability and durability of the form-retaining member. [Effects of the Invention]

[0035] Footwear equipped with the shape-retaining member according to the present invention has the following excellent effects. 1. Maintaining the aesthetic appearance and silhouette of the exterior. The shape-retaining member of the present invention has a blade-like shape with a smooth, unidirectional, or linearly extending rear contour and gradually tapering edges. This design allows the shape-retaining member to be completely embedded between the upper and lining materials, preventing the rearward curvature and external exposure of the member's contour that were problems in the prior art. As a result, it is possible to maintain the flat, refined upper surface and upright, neat silhouette required of footwear, especially formal shoes, without compromising them. 2. Achieving both tool-free attachment / detachment and secure heel retention. This invention integrates the on / off guidance function of an inclined "slide section" and the heel-wrapping and positioning function of "protrusions" and "extensions" that extend inward into the shoe into a single composite curved surface shape. This allows for smooth on and off while naturally guiding the foot, and after wearing, it securely holds the heel to prevent slippage or falling out during walking. In other words, it simultaneously achieves at a high level two functions that were previously in a trade-off relationship: "ease of putting on and taking off" and "stable retention." 3. Excellent support, shape retention, and durability The optimized thickness distribution, which gradually decreases from the thickest "convex" portion of the shape-retaining member through the center of the "support portion" to the edge, and the "approximately T-shaped support keel" structure, provide high support rigidity and shape retention to the entire heel area. This effectively prevents indentation deformation of the instep due to repeated foot strikes and long-term use. Furthermore, by using highly elastic and fatigue-resistant resins such as TPU as the integral molding material, superior durability against aging and load fatigue is achieved compared to conventional fixed-form materials such as chemical sheets and hot melts. 4. Simplification of the manufacturing process and improvement of versatility. The shape-retaining component is fixed to the upper end of the heel section by a simple stitching, significantly reducing the need for complex bonding and wrapping processes. Furthermore, the design of the extension section, which has a "hollow space," allows for high compatibility with various sizes and shapes of shoe lasts, resulting in excellent manufacturing versatility. This enables cost-effective mass production while maintaining appearance quality. 5. Applicability to a wide range of footwear types The technology of this invention, with its core features of "embedded structure that does not impair appearance" and "integrated functionality," can be widely applied not only to formal shoes but also to sneakers, casual shoes, and other types of footwear where appearance and design are important. This makes it possible to achieve both hands-free functionality and excellent appearance quality in a diverse product line. To more clearly illustrate the technology in the embodiments of the present invention, a brief explanation will be given using the following drawings. The drawings in the following explanation are some embodiments of the present invention, and those with ordinary skill in the art can use these drawings to obtain other drawings without requiring any creative effort. [Brief explanation of the drawing]

[0036] [Figure 1] This is an illustrative diagram of footwear according to one embodiment of the present invention. [Figure 2] This is a side cross-sectional view of a form-retaining member according to one embodiment of the present invention. [Figure 3] This is a plan view of a form-retaining member according to one embodiment of the present invention. [Figure 4] This is a side cross-sectional view of a form-retaining member according to one embodiment of the present invention. [Figure 5] This is a bottom view of a form-retaining member according to one embodiment of the present invention. [Figure 6] This is a cross-sectional view of the slide portion of a form-retaining member according to one embodiment of the present invention, in the direction of A1-A2 in Figure 2. [Figure 7] This is a cross-sectional view in the direction of B1-B2 of the support portion of a form-retaining member according to one embodiment of the present invention. [Figure 8] This is a side cross-sectional view of the heel portion of one embodiment of the present invention. [Figure 9] This is a front view of a form-retaining member according to one embodiment of the present invention, with the dashed line in the middle representing the approximate area of ​​a roughly "T"-shaped support keel. [Figure 10] This is a comparative image of the width of the heel opening of footwear according to one embodiment of the present invention and the width of the heel of the foot. The dashed line in the middle indicates the heel of the foot. Image a shows an image where the heel opening has a polygonal shape, and image b shows an image where the heel opening has a curved shape. [Modes for carrying out the invention]

[0037] The art of embodiments of the present invention will be described clearly and completely below with reference to the drawings of the embodiments. Clearly, the embodiments described are some, but not all, embodiments of the present invention. All other embodiments that can be obtained by a person of ordinary skill in the art based on embodiments of the present invention without requiring any creative effort are within the scope of the present invention. Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 10.

[0038] As shown in Figure 1, an embodiment of the present invention provides footwear equipped with a shape-retaining member 100, which consists of a heel portion 10 of the shoe and a shape-retaining member 100 provided between the outer material 20 and inner material 30 of the heel portion 10. The shape-retaining member 100 is manufactured by integral molding of resin material with an alloy mold, and in one embodiment, the shape-retaining member 100 is made of TPU which has support force and elasticity, and simultaneously possesses excellent support force and flexibility. That is, while ensuring the support rigidity necessary to maintain the shape of the heel portion, it has flexibility that can be flexibly deformed according to the various specifications of the last (shoe-making mold), achieving both structural stability and adaptability, and further possessing advantages such as abrasion resistance, durability and high temperature resistance, ensuring the sustainability and durability of the shape-retaining member 100. TPU with a Shore hardness of A80-90 degrees is preferred.

[0039] In an embodiment of the present invention, as shown in Figure 2, the shape-retaining member 100 includes a slide portion 101, a support portion 102, and an extension portion 104. The slide portion 101 has a surface facing the foot that is inclined diagonally backward, and as shown in Figure 3, both sides are inclined downward in a bracketed arc shape, forming a guide structure for the heel of the foot to slide smoothly into the footwear.

[0040] Preferably, the inclination angle of the slide portion 101 can be set to 25 to 50 degrees relative to the vertical line to optimize the heel sliding effect. The inclination angle of the slide portion 101 can be set within the range of 20 to 60 degrees, and 30 to 60 degrees is preferable for the need for quick putting on and taking off of business shoes, etc.

[0041] In one embodiment, as shown in Figures 4 and 6, the inner and outer sides of the slide portion 101 may extend diagonally forward of the footwear, forming two wing portions 105.

[0042] In this configuration, the two wing portions 105 are formed integrally and continuously from the slide portion 101, and their thickness may have a tapered shape that gradually thins from the slide portion 101 towards the tip of the wing portion 105. The direction in which each wing portion 105 extends has an inclination angle that is obliquely downward and forward when viewed from the side of the footwear, and when viewed from the top, the outer wing portion 105a is arranged to open obliquely forward and outward, and the inner wing portion 105b is arranged to open obliquely forward and inward.

[0043] Preferably, the acute angle at which the extensions of the two wing portions 105 intersect is within the range of 30 to 60 degrees. This angle range is optimized so that the wing portions 105 can provide effective stiffening and guiding functions while ensuring sufficient support area within the structure of the heel portion 10.

[0044] Preferably, the length of the wing portion 105 is such that it does not reach the inner or outer ankles, and from the viewpoint of the footwear's "inconspicuous structure" and "consistency in appearance," the upper edge is chamfered and the lower edge is edge-shaped to avoid discomfort from contact with the foot and prevent the contour from protruding from the outer material 20. The wing portion 105 has a side shape that is approximately straight or slightly outward convex curve, forming a three-dimensional structure with respect to the front-to-back and inward-to-outward directions of the heel portion 10. As a result, the shape-retaining member 100 constitutes a support frame that three-dimensionally wraps around the side and diagonally forward of the heel portion 10, suppressing unnatural lateral movement and rotation of the heel when worn. Furthermore, the shape-retaining member 100, with its slide portion 101 and the pair of wing portions 105 extending from it, guides the insertion of the heel and realizes a combined function of stably holding the heel from multiple directions while being worn. Furthermore, as shown in Figure 2, a protrusion 103 is formed at the lower part of the inclination of the slide portion 101, projecting toward the toes. Referring to the vertical line in the figure, the protrusion 103 has a shape in which at least a part of it protrudes most toward the toes relative to the other parts of the shape-retaining member 100. This protrusion 103 functions as a stopper to prevent the heel of a foot that has slid down the slide portion 101 into the footwear from easily coming out.

[0045] Preferably, the protrusion 103 has a smooth, curved shape that contacts the heel, conforms to the upper rear contour of the heel, does not hinder the movement of the heel during putting on or taking off, and is shaped to engage securely when held in place.

[0046] In one embodiment, as shown in Figure 2, the support portion 102 and the extension portion 104 are connected and extended sequentially in an arc along the contour of the heel of the foot, below the convex portion 103. As shown in Figure 2, the extension portion 104 bulges backward, and as shown in Figure 5, both sides are arc-shaped and inclined upward, forming a shape that fits the heel of the foot. The thickness of the support portion 102 decreases from the bottom and continues to decrease towards the extension portion 104, all the way to the edge of the extension portion 104, forming an end that can be drawn with a single line. Because the convex portion 103, the support portion 102, and the extension portion 104 are formed integrally and continuously, the force transmission path is clearly defined, and the multi-directional load received from the heel is efficiently distributed and absorbed. In particular, the fact that the edge of the extension portion 104 has an "end that can be drawn with a single line" prevents stress concentration and reduces the risk of cracking or breakage. When the footwear is worn, the convex portion 103, the support portion 102, and the extension portion 104 form a shape that fits the heel of the foot. The arc shape that follows the skeletal contour of the heel and the three-dimensional shape that fits it distribute the pressure points on the heel, reducing localized load and fatigue. As a result, comfort is maintained even when worn for long periods of time.

[0047] Preferably, the support portion 102 and the extension portion 104 are integrally formed with the slide portion 101 and the two wing portions 105, and may include a structure for fixing the shape-retaining member 100 inside the heel portion 10 of the footwear and for reinforcing the connection with the midsole and outsole. As a result, the shape-retaining member 100 functions as a strong, integrated frame that encloses the heel, contributing to the overall structural stability and durability of the footwear.

[0048] In one embodiment, as shown in Figure 4, the right rear side of the shape-retaining member 100 does not have any noticeable irregularities, and the rear contour line is smooth. Furthermore, the rear contour line from the upper end to the lower end of the shape-retaining member 100 is inclined in a single direction or extends in a substantially straight line, which allows the appearance of the member to be simple and does not detract from the aesthetic appeal of the footwear.

[0049] Preferably, as shown in Figure 4, the thickness of the protrusion 103 is set to 7 mm, making it the thickest part compared to the thickness of all other parts of the form-retaining member 100 (e.g., the central part of the support portion 102 has a thickness of 4 mm, and the middle part of the extension portion 104 has a thickness of 2 mm). This 7 mm thickness tapers continuously and without steps from the protrusion 103 towards the support portion 102, and further decreases in a smooth gradient from the support portion 102 to the edge of the extension portion 104. Specifically, the thickness is continuously reduced from the apex of the convex portion 103 (thickness 7 mm) to the central part of the support portion 102 (thickness 4 mm) to the intermediate position of the extension portion 104 (thickness 2 mm) to the edge end of the extension portion 104 (thickness 0.3 mm or less), forming a sharp end that is essentially edge-like, that is, a sharp end that can be drawn with a single line.

[0050] In one embodiment, the lower part of the extension 104 has the thinnest wall thickness, and in the injection molding process, it can be easily inserted into the gap between the last (aluminum mold of the foot) and the heel portion 10 of the sole mold, allowing the mold to be tightly closed and sufficient clamping force to be applied, thereby preventing material leakage (burr generation) from the parting line (joint surface) of the mold during the injection molding process of the sole material. Therefore, at least the lower part of the extension 104 should have a wall thickness that enables sealing between the last and the sole mold in the injection molding process. Furthermore, as shown in Figure 6, the wall thickness of the convex portion 103 gradually decreases from its center toward both the inner and outer edges, conforming to the natural shape of the heel, fitting well, and reducing unnecessary protrusion from the side. Furthermore, as shown in Figure 7, the central region of the support portion 102 has the greatest wall thickness, and its thickness gradually decreases toward the inner and outer edges. This design provides sufficient support rigidity in the central area where the heel 10 directly receives the load, while also providing appropriate flexibility towards the sides, optimizing the balance between comfort and structural strength.

[0051] Furthermore, as shown in Figure 9, the maximum thickness region of the protrusion 103 and the central thickness region of the support portion 102 are continuous, forming a robust support keel 106 that is roughly "T" shaped overall inside the shape-retaining member 100. In this support keel 106, the protrusion 103 forms a "T" shaped cross section, fitting to the upper rear side of the heel and reinforcing its support function as a stopper. On the other hand, the central region of the support portion 102 forms a "T" shaped longitudinal section, reinforcing the shape retention of the entire heel portion 10 and effectively preventing indentation deformation of the exterior material 20 and interior material 30 due to repeated foot pressure. The thickness of the support keel 106 is controlled within a range of 5 mm to 15 mm, taking into consideration optimal support performance and weight reduction. Also, as shown in Figures 6 and 7, the cross-sectional view of the support keel 106 shows that the curve of the outer arc-shaped edge is smooth and has a smaller curvature than the arch curvature of the inner arc-shaped edge. This design maintains a discreet and simple silhouette externally, while ensuring ample support space and strength internally to conform to the skeletal shape of the heel, thus achieving a high degree of balance between functionality and aesthetics.

[0052] According to several embodiments of the present invention, the combination of the support force of the thick support keel 106 and the flexibility of the thin extension 104 simultaneously provides the heel with high shape retention and appropriate flexibility, achieving both structural stability and shoemaking suitability for long-term use of footwear. The interior material 30, which incorporates the protrusion 103, rises in the direction of the toe, forming a raised structure 12. As shown in Figure 8, the point of maximum protrusion of this raised structure 12 in the direction of the toe is located furthest toe (forward).

[0053] In one embodiment, as shown in Figure 8, a cushioning material 40 such as a shrinkable sponge is placed between the interior material 30 and the shape-retaining member 100. When the heel slides diagonally forward and downward along the sliding surface of the slide portion 101 and reaches the most protruding point of the convex portion 103, the cushioning material 40 is compressed and thinned, and with the help of inertia and the elasticity of the outer material 20, the heel can smoothly pass over the most protruding point of the convex portion 103 and slide forcefully into the footwear. After the heel enters the footwear, the cushioning material 40 and outer material 20 quickly return to their original state, and the stopper action of the convex portion 103 causes the heel portion 10 to tightly enclose the heel, making it difficult for it to fall out.

[0054] In another embodiment of the present invention, if the heel slides diagonally forward and downward along the sliding surface and reaches the most protruding point of the protrusion 103, the heel may not be able to enter smoothly due to obstruction by the protrusion 103. In this case, by providing an expandable structure at the opening of the footwear, the opening can be widened by the tension created by the insertion of the foot. After the foot enters the footwear, the expandable structure elastically recovers, allowing the protrusion 103 to precisely position the heel.

[0055] In one embodiment, as shown in Figure 9, the extension portion 104 is provided with a retractable or expandable hollow portion 108 (notch), the maximum expandable amount of which is set to 15 mm. This design makes it possible to accommodate the heel shapes of various standard lasts (shoe molds) within the general size range of 22.0 cm to 28.0 cm. Furthermore, when worn, this retractable hollow portion 108 works in conjunction with the convex portion 103 and the wing portion 105 to tightly wrap around the heel from all directions, significantly improving the fit and stability. Of course, one or more hollow portions 108 (notches) can be provided as needed.

[0056] In one embodiment, the shape-retaining member 100 has a structure for securely fixing to the heel portion 10. In some embodiments of the present invention, as shown in Figure 9, a sewn portion 107 is provided at the upper part of the shape-retaining member 100 and in the center in the left-right direction, for the purpose of fixing to the upper end of the heel portion 10 of the footwear.

[0057] Preferably, the horizontal width of the sewn portion 107 is 0.5 cm or more, and its thickness is approximately 0.05 cm. This dimensional setting ensures sufficient strength and ease of handling as a seam allowance, while preventing the seam from becoming bulky and causing discomfort or pressure inside the footwear. Furthermore, because the sewn portion 107 has a thin plate-like shape that extends smoothly and continuously from the main body of the shape-retaining member 100, the needle passes through easily during the sewing process, and stress concentration around the seam is reduced, thereby reducing the risk of seam fraying and damage to the member itself with long-term use.

[0058] With this configuration, the shape-retaining member 100 is securely and durablely fixed to the heel portion 10 of the footwear, and as a result, the shape-retaining member 100 does not shift or deform during walking or exercise, and a consistent heel-holding and support function can be performed. Furthermore, the horizontal width of the slide portion 101 in the left-right direction is smaller than the horizontal width of the human heel. In the embodiment of the present invention, considering support force and aesthetics, the width of the slide portion 101 is preferably 3 to 4.5 cm and the thickness is preferably 0.15 to 0.25 cm.

[0059] Furthermore, in order to prevent the heel portion 10 from appearing unnecessarily high in the appearance of the footwear, in the embodiments of the present invention, it is desirable to set the height (H1) of the slide portion 101 to less than half, preferably in the range of one-third to one-half, of the height (H2) of the extension portion 104. This proportional relationship gives the shape-retaining member 100 and the center of gravity of the entire shoe a visually and substantially lower and more stable impression, and enables structurally more efficient force transmission.

[0060] Preferably, the height ratio can be adjusted according to the type of footwear (e.g., sports shoes, business shoes, etc.) and design, within a range where the slide portion 101 does not impair its function as an insertion guide and the extension portion 104 can secure a sufficient support area. This configuration achieves a balance between aesthetics and functionality, reducing excessive heel protrusion, giving the footwear a sleeker silhouette, and improving practical stability when worn.

[0061] When the footwear is worn, the protrusion 103 takes on a shape that surrounds at least part of the lower part of the Achilles tendon and the rear of the heel. As a result, the protrusion 103 works in conjunction with the support part 102 and the extension part 104 to three-dimensionally wrap around the heel of the foot, forming an integrated holding structure. This configuration uniformly supports and holds the entire heel, including the area around the Achilles tendon, against multidirectional forces applied to the heel during walking and exercise, especially downward pulling forces. As a result, it effectively prevents the footwear from unexpectedly slipping off or excessively shifting, and greatly improves dynamic stability.

[0062] Preferably, the inner surface of the protrusion 103 that contacts the Achilles tendon is a smooth curved surface to reduce pressure and friction on the skin, and its curvature is set within a range that does not hinder the range of motion of the ankle joint when standing and walking.

[0063] In one embodiment, as shown in Figure 9, the upper part of the form-retaining member 100 is arc-shaped, and both side edges of the upper part have a shape that gradually widens diagonally downward from the slide portion 101 to the extension portion 104. The shape that widens diagonally downward forms a path that efficiently distributes and transmits the insertion force from above that the slide portion 101 receives and the impact force that the heel receives when landing to the extension portion 104, which has a large surface area. Optimizing this flow of force suppresses deflection and deformation of the member itself and increases durability. From the viewpoint of further optimizing the overall stability of the form-retaining member 100 and the support performance for the slide portion 101, it is preferable that the width (W2) of the extension portion 104 be set to approximately 1.5 times the width (W1) of the slide portion 101. This 1:1.5 width ratio ensures that the extension 104 has sufficient width relative to the slide portion 101, allowing support for the heel portion 10 to extend laterally and improving stability during landing.

[0064] More preferably, the width ratio can be adjusted within a range of 1.2 to 1.8 times, depending on the type of footwear (running shoes, business shoes, etc.) and the required support rigidity. This ensures flexibility in application to a variety of product designs.

[0065] In conventional shoe heel shaping methods, a shaping material 200, such as a chemical sheet or hot melt adhesive, is usually attached to the inside of the heel shaping material 10 to maintain the appearance and aesthetics of the shoe body. Specifically, the chemical sheet is softened with a solvent, molded into a predetermined shape, and then dried and hardened on the shoemaking line. On the other hand, the hot melt adhesive is softened by heating on the shoemaking line, molded in the same way, and then cooled to maintain the shape of the heel shaping material 10 of the last (shoe mold). Both materials need to be fixed between the outer material 20 and the inner material 30 during the upper manufacturing process. In this process, the outer material 20 and the inner material 30 are first sewn together with their right sides facing each other at the opening, and then turned inside out along the seam line in what is known as the "turning inside out process." After turning inside out, the shaping material 200 is inserted and placed between the outer material 20 and the inner material 30.

[0066] In this embodiment of the present invention, first, the outer material 20 and the inner material 30 are sewn together with their right sides facing each other at the opening. During this sewing, the shape-retaining member 100 is placed inside the inner material 30, and its sewing portion 107 is simultaneously sewn into the seam allowance of the outer material 20 and the inner material 30. After that, the entire assembly is turned inside out along the seam (turning process). As a result, the shape-retaining member 100 is securely positioned between the inner material 30 and the outer material 20, and the concave surface of its extended portion 104 adheres to the inner material 30, while the bulging portion adheres to the outer material 20. This method eliminates the need for pre-treatment steps such as spray bonding that were previously required, simplifying operation and shortening the process.

[0067] Furthermore, after turning the material inside out, the pre-formed material 200 is inserted between the outer material 20 and the inner material 30 as needed. It is preferable to place the pre-formed material 200 on the back side (outer material 20 side) of the shape-retaining member 100. This prepares the structure for the formation of a strong support structure in which the shape-retaining member 100 and the pre-formed material 200 are integrated in subsequent steps. Furthermore, at the lower part of the outer material 20, the outer material 20, the lower end of the extension portion 104 of the shape-retaining member 100, the pre-formed material 200, and the inner material 30 are overlapped and sewn together to form a lasting allowance. This sewing aligns the edges of all the components, making the attachment of the midsole and other components in subsequent steps easier and more accurate. After sewing, any excess portion of the extension portion 104 that extends beyond the lasting allowance is cut off. Furthermore, in the final molding process of the footwear (heat and pressure molding using hot melt, etc.), the adhesive pre-formed material 200 softens and firmly adheres and solidifies to the back side of the shape-retaining member 100. As a result, the two components form a single integrated structure, improving the support rigidity and shape retention of the heel portion 10. This series of processes eliminates the need for excessive processing compared to conventional upper manufacturing, making it possible to produce footwear that combines superior structural performance and aesthetic appeal.

[0068] In embodiments of the present invention, as shown in Figures 1 and 8, the shoe body manufactured by the process of the present invention has an upper heel portion 11 that extends posteriorly and upward, widening the foot insertion space at the opening and making it easier to insert the foot. At the same time, the interior material 30 of the upper heel portion 11 forms a slide-like curved surface that slopes toward the inside of the footwear, and furthermore, the upper end of the interior material 30 extends upward, covering the highest point of the heel portion and featuring a structure that adheres precisely to its contour. Inside the footwear, the protrusion 103 and filling material form a raised structure 12 on the underside of the heel portion 10, so that the shoe fits the heel of the foot when worn and prevents the shoe from falling off.

[0069] In embodiments of the present invention, the following cushioning structure can be added to improve foot comfort. Specifically, a flexible cushioning material 40, such as sponge or foam, is attached or laminated to the back surface of the lining material 30 on the inside of the footwear. This softens the contact surface with the heel, absorbing impact upon landing and reducing everyday pressure.

[0070] In one embodiment, a cushioning filler or soft coating is applied to the foot-side contact surface of the shape-retaining member 100 (particularly the slide portion 101 and the protruding portion 103). This maintains the structural support function of the shape-retaining member 100 while softening the feel of the direct contact area with the foot and preventing pressure concentration on specific areas. These cushioning treatments enable the footwear of the present invention to provide not only excellent retention and support functions but also comfortable wear even during prolonged use. Furthermore, by using both cushioning methods in combination as needed, optimal shock absorption and fit can be achieved.

[0071] In one embodiment, a design with the following structural adaptability is adopted to accommodate a variety of shoe sizes. The shape-retaining material 200, such as chemical sheets or hot melt adhesives, used is sized according to the shoe size. Meanwhile, the shape-retaining member 100 is securely fixed to the upper end 11 of the heel portion via the sewing portion 107, but the lower end of its extension 104 may be designed to not reach the bottom sole of the instep.

[0072] As shown in Figure 8, this design allows the extension portion 104 of the shape-retaining member 100 to not cover the length of the heel portion 10, forming a "free support state" where it is supported independently from the outer material 20 and the inner material 30. In this state, the inclination angle and position of the shape-retaining member 100 are confirmed and adjusted using a predetermined positioning tool or marking (positioning point), and then the mold material 200 is heated and pressurized (molding). As a result, the softened mold material 200 completely conforms to the shape of the back surface of the shape-retaining member 100 and adheres tightly, and after cooling and solidification, the two form a strong, integrated structure. It is also preferable to sew the shape-retaining member 100 and the mold material 200 together beforehand using the thin extension portion 104. By deliberately designing the lower end of the shape-retaining member 100 to be short, flexibility is created that allows the same shape-retaining member 100 to be applied to footwear with different lengths (heel portion 10 heights). By combining this with size adjustments for the standard mold material 200, it becomes possible to accommodate a wide range of product lines. Furthermore, even in a "free support state," positioning and angle confirmation prevents misalignment or excessive tilting of the mold-retaining member 100 during molding, ensuring complete and uniform adhesion with the standard mold material 200. Ultimately, integration with the standard mold material 200 ensures that the support rigidity and shape retention performance of the entire heel portion 10 are not compromised, but rather an optimized reinforcement structure for the size is obtained. Therefore, this embodiment achieves high adaptability to various shoe sizes and designs while standardizing parts and improving manufacturing efficiency.

[0073] In this embodiment of the present invention, as shown in Figure 8, the foot-facing surface of the slide portion 101 of the shape-retaining member 100 is inclined upward and backward. Since this slide portion 101 functions as a structure that supports the upper end portion 11 of the heel, the foot-facing surface of the upper end portion 11 of the heel is also inclined upward and backward. This design widens the space for inserting the foot into the opening, making it easier to put on and take off the shoes. At the same time, the width of the slide portion 101 of the shape-retaining member 100 is intentionally set to be narrow. Consequently, the width of the opening of the heel portion 10 is also formed to be smaller than the horizontal width (anatomical width) of the human heel. This dimensional relationship creates an effect in which the opening appropriately holds the heel after the foot is inserted.

[0074] Specifically, as shown in Figure 10, the radius of curvature of the shape formed by the opening inside the footwear is set to be smaller than the natural radius of curvature of the human heel, and its inner angle is formed to be acuter than the anatomical angle of the human heel 10. The dashed line in the figure represents the heel of the foot, with a being an image of the heel opening forming a polygonal shape, and b being an image of the heel opening forming a curved shape. This design, through the narrow design of the slide portion 101 and the optimization of the radius of curvature or inner angle, allows the opening to moderately tighten and hold the heel after the foot is inserted. This improves the stability of the fit and prevents the foot from slipping off. Furthermore, the slide portion 101 acts as a framework that supports the upper end, so that the shape of the heel portion 10 is maintained even with repeated putting on and taking off and under load.

[0075] In one embodiment, the upper part of the slide portion 101 is sloped backward, and both sides are sloped forward in a bracket-like arc shape, forming a slide for the heel to slide into the footwear. This design allows the heel of the foot to slide smoothly into the shoe, avoiding friction and obstruction between the heel and the heel portion 10, and improving the smoothness and comfort of putting on the shoe.

[0076] In one embodiment, the shape-retaining member 100 is manufactured from a polymer material, such as a resin or plastic material, that has a certain degree of support strength and tough elasticity. In selecting the material, new high-elasticity materials such as TPU (polyurethane), TPE (thermoplastic elastomer), and TPEE (thermoplastic polyester elastomer) are recommended. These materials have good elasticity and toughness, can provide sufficient support, and also have advantages such as abrasion resistance, durability, and high temperature resistance. Therefore, the shape-retaining member 100 manufactured from these new high-elasticity materials can effectively meet the structural requirements of the shoe while simultaneously ensuring comfort and durability during wear.

[0077] In one embodiment, the mold-retaining member 100 is integrally molded by injection molding using a metal mold. The metal mold uses 738H mold steel, which is resistant to damage, aging, and deformation, and has a long service life, thus saving on maintenance costs. This means that there is no need to frequently replace or maintain the mold in the production process, further reducing production costs.

[0078] In one embodiment, the shape-retaining member 100 can be made of a pre-formed material 200 such as a chemical sheet or hot melt adhesive, and the same hands-free wearing effect can be achieved. Specifically, the shape-retaining member 100 of the above material is first attached to the upper end 11 of the heel portion 10 by sewing or adhesive, and then molded by sandwiching it between the conventional pre-formed material 200, the outer material 20 and the inner material 30. The shape-retaining member 100 made by this method does not have the same durability as TPU, but it is suitable for short-lived footwear (for example, event shoes intended for temporary use or shoes intended for short-term use).

[0079] In one embodiment, when a person puts on a shoe, the tip of the foot is placed inside the shoe and the heel is pressed down, causing the heel to slide into the footwear along the upper end 11 of the inclined heel portion 10. After the heel is inside the footwear, the raised structure 12 fits the heel, making it difficult for the heel to slip out.

[0080] In one embodiment, the form-retaining member 100 includes a center position mark at a location corresponding to the center of the heel portion 10. The center position mark is a geometrically shaped mark with raised and recessed areas, and during the manufacturing process, the center position mark can be identified visually and tactilely to accurately align the form-retaining member 100 to the center of the heel portion 10. The position mark employs a geometrically shaped structure with raised and recessed areas, forming a clear position indicator. Its shape is circular or linear, with a diameter of 1 millimeter and a height and depth of 0.5 millimeters, making it identifiable without causing the foot to protrude.

[0081] In one embodiment, a fine texture is applied to the surface of the form-retaining member 100. The depth of these textures is 0.5 millimeters or less, and the shape can be linear, mesh-like, dotted, matte, rough, wavy, spotted, uneven, spiral, granular, etc. These textures are distributed on the surface of the form-retaining member 100 and are used to increase the contact area and adhesion strength with the form-forming material 200.

[0082] In one embodiment, the shape-retaining member 100 can be used in multiple manufacturing processes, including cementing, sewing, crimping, injection molding, vulcanization, Goodyear welding, and California welding. These can be selected based on the characteristics of the material, the suitability of the production equipment, and the differences in the production environment. The structure formed by the shape-retaining member 100 and the molded material 200 is effectively fixed inside the heel portion 10, providing the necessary performance and stability for the entire footwear.

[0083] In one embodiment, a method for manufacturing footwear equipped with a shape-retaining member 100 includes the following procedure. a. Preparation of the form-retaining member 100: The form-retaining member 100 is manufactured using a resin material (e.g., TPU) that has bearing capacity and flexibility, by a molding process (e.g., injection molding). b. Attachment of the shape-retaining member 100: The shape-retaining member 100 is fixed up to the upper end 11 of the heel portion of the shoe. Specifically, the upper stitched portion 107 of the shape-retaining member 100 is sewn or glued to the upper end 11 of the heel portion 10 to ensure that the shape-retaining member 100 is in the correct position on the heel portion 10, allowing the heel to slide in effectively and fit the heel when wearing the shoe. c. Turning inside out process: The specific operation is as follows. First, the exterior material 20 and the interior material 30 are sewn together facing each other at the opening, and then they are turned inside out along the seam, that is, the turning inside out process is performed. After turning inside out, the shape-retaining member 100 and the shape-setting member 200 are sandwiched between the exterior material 20 and the interior material 30. d. Shape reinforcement: Shape-making (e.g., molding by heating or pressurizing) is performed so that the shape material 200 adheres closely to and integrates with the shape-retaining member 100, ensuring the shape stability and support capacity of the shape-retaining member 100, and enabling the shoe to maintain a good shape and performance when worn. [Explanation of symbols]

[0084] 1. Footwear 10 Heel 11 Upper end of the heel 12 Raised structure 20 Exterior materials 30 Interior materials 40 Cushioning material 100 Shape-retaining member 101 Slide section 102 Support part 103 Convex part 104 Extension 105 Wings 106 Support Keel 107 Sewing department 200 Fixed material

Claims

1. Footwear, The heel portion includes a shape-retaining member composed of curved surfaces having multiple different radii of curvature, The aforementioned form-retaining member is formed by integral molding of a resin material using an alloy mold, and possesses both support capacity and flexibility. The shape-retaining member includes a slide portion, a support portion, an extended portion, and a protrusion that extends in the direction of the toe. In a front view, the upper part of the form-retaining member has an arc shape, and both side edges of the upper part have a shape that gradually widens diagonally downward from the slide portion to the extension portion. In a side view, the slide portion has a surface facing the foot that slopes diagonally backward, and in a plan view, both sides are curved and slope downward, forming a guide structure for sliding the heel of the foot into the footwear. In a side view, the protrusion, the support portion, and the extension portion are formed to fit the heel of the foot. The thickness of the aforementioned protrusion is at least partially thicker than that of other parts of the form-retaining member. In a side view, the aforementioned protrusion extends at least partially toward the toe side relative to the other parts of the shape-retaining member. The thickness gradually decreases from the support portion to the edge of the extension portion, and at least a portion of the extension portion has a thickness that allows for sealing between the last and the sole mold in the injection molding process. Footwear characterized in that, when a user puts on the footwear, the heel of the foot slides along the inclined slide portion, and the protrusion fits the heel of the foot, making it difficult to slip off.

2. The footwear according to claim 1, characterized in that the shape-retaining member is integrated and reinforced with a shape-retaining material.

3. The footwear according to claim 1, characterized in that a sewn portion is provided at the upper end of the shape-retaining member, and the shape-retaining member is fixed to the heel portion.

4. Footwear, The heel portion includes a shape-retaining member composed of curved surfaces having multiple different radii of curvature, The aforementioned form-retaining member is formed by integral molding of a resin material using an alloy mold, and possesses both support capacity and flexibility. The shape-retaining member includes a slide portion, a support portion, an extended portion, and a protrusion that extends in the direction of the toe. In a side view, the slide portion has a surface facing the foot that slopes diagonally backward, and in a plan view, both sides are curved and slope downward, forming a guide structure for sliding the heel of the foot into the footwear. In a side view, the protrusion, the support portion, and the extension portion are formed in a shape that fits the heel of the foot. In the side cross-sectional view, the form-retaining member does not have any noticeable irregularities at the rear, its rear contour is smooth, and extends in a single direction from the upper end to the lower end, either in an inclined or substantially linear manner. The aforementioned protrusion has at least one portion that is the thickest part of the shape-retaining member compared to the rest of the member, and in a side view, at least one portion protrudes furthest towards the toe relative to the rest of the shape-retaining member. The thickness of the protrusion gradually decreases from the support portion to the edge of the extension portion. Footwear characterized in that, when the aforementioned protrusion is attached to the footwear, it forms a raised structure in the interior material, fits the heel of the foot, and prevents it from coming off.

5. The footwear according to claim 4, characterized in that both the inner and outer sides of the slide portion extend diagonally forward of the footwear, forming two wing portions, and the angle at which the extensions of the two wing portions intersect is acute.

6. The convex portion and the central region of the support portion constitute a roughly T-shaped support keel with a relatively thick wall thickness. The footwear according to claim 4, characterized in that the convex portion constitutes the substantially T-shaped cross section, and the central region of the support portion constitutes the substantially T-shaped longitudinal section.

7. Footwear, including a heel portion having a shape-retaining member, the shape-retaining member including a slide portion for sliding the heel of the foot into the footwear, a protrusion for preventing the heel of the foot from slipping off, a support portion and an extension portion, The horizontal width of the aforementioned slide section is smaller than the horizontal width of a person's heel. The interior material at the upper end of the heel portion forms a slide-like curved surface that slopes toward the inside of the footwear, and furthermore, the upper end of the interior material extends upward and covers the highest point of the heel portion. The width of the heel opening is set to be smaller than the horizontal width of the human heel, and the radius of curvature of the shape formed by the heel opening inside the footwear is set to be smaller than the natural radius of curvature of the human heel. The interior material containing the aforementioned protrusions rises in the toe direction to form a raised portion, and in the side cross-sectional view, the point of the most protruding portion in the toe direction is the point that extends the furthest in the toe direction. Furthermore, the footwear is characterized in that at least a portion of the extended portion has a thin wall thickness that enables manufacturing by injection molding.

8. The footwear according to claim 7, characterized in that the extended portion has one or more hollow portions to fit a variety of last sizes.

9. The footwear according to claim 7, characterized in that the footwear is manufactured by an injection molding process.

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