Orthotic shoe with removable tongue

Abstract

The application relates to the technical field of medical devices and functional footwear, and discloses a correction shoe with a detachable tongue, which comprises an inner layer support structure formed by embedding a net-shaped shape memory alloy wire into a flexible base, and a temperature sensing polymer outer layer with a Tg of 32-38 DEG C; the tongue is detachably connected with the shoe body through a buckle or magnetic attraction structure, can adaptively adjust the arc with the change of the foot temperature, release the pressure, and support replacement to adapt to different rehabilitation stages, and has the properties of sanitary maintenance and biomechanical adaptability. The correction shoe combines the temperature response deformation of the tongue with the static support of the shoe sole, dynamically adjusts the dorsum pedis pressure distribution in the gait cycle, avoids the formation of local high pressure points, and supports various application scenes such as postoperative rehabilitation, sports protection and chronic foot disease management.

Description

Technical Field

[0001] This invention belongs to the field of medical devices and functional footwear technology, specifically an orthotic shoe with a detachable tongue. Background Technology

[0002] In the field of foot orthotics, the design of orthopedic shoes and their key components, such as insoles, soles, and tongues, has a significant impact on treatment outcomes. In recent years, with the development of personalized medicine and smart wearables, orthopedic shoes targeting various foot problems (such as flat feet, hallux valgus, and gait abnormalities) have emerged, and their structures and materials have been continuously optimized. However, current technologies have paid relatively little attention to the tongue, a crucial contact area, especially in terms of adapting to changes in foot dorsum shape, facilitating cleaning and replacement, and complementing overall orthopedic function; there is still room for improvement in these areas.

[0003] Patent CN207708058U discloses a multifunctional orthotic shoe for children, including an upper, toe, sole, tongue, and an orthotic device built into the shoe. The tongue is padded and connected to the upper part of the shoe via a strap. The overall structure aims to improve the comfort and orthotic effect for children with cerebral palsy. While this design incorporates a padded tongue to enhance fit, the tongue is fixedly connected to the shoe body and lacks detachability. This makes cleaning and maintenance difficult during daily use, and also limits its adaptability to different levels of foot swelling or rehabilitation stages, restricting its flexibility during dynamic orthotic procedures.

[0004] Patent CN208259162U discloses a customizable orthopedic shoe with a sole made of thermoplastic material that can be softened by heat and shaped according to the user's foot shape, thereby achieving personalized correction. This solution emphasizes the adjustability of the sole but does not address the optimization design of the tongue structure. The tongue still uses a traditional fixed structure, failing to solve the problems of pressure discomfort or insufficient fit caused by changes in the shape of the instep (such as postoperative swelling, post-exercise congestion, etc.), nor does it consider the potential role of the tongue as a contact surface in hygiene, replacement, and phased orthopedic interventions.

[0005] In summary, while the two valid patents mentioned above offer innovations in the overall structure or partial function of orthotic shoes, they do not yet provide effective solutions regarding the detachability and adaptability of the tongue, as well as its synergy with the overall orthotic strategy. Therefore, it is necessary to propose an orthotic shoe with a detachable tongue to improve the flexibility, hygiene, and individual fit of orthotic shoes in practical applications. Summary of the Invention

[0006] This invention provides an orthopedic shoe with a detachable tongue. Its core lies in integrating a mesh shape memory alloy wire and a temperature-sensitive polymer composite layer into the tongue structure to achieve an adaptive response to dynamic deformation of the instep. Combined with a detachable connection structure, it improves the overall performance of the orthopedic shoe in terms of hygiene maintenance, phased intervention, and personalized adaptation.

[0007] This invention provides an orthopedic shoe with a detachable tongue, comprising a shoe body and a detachable tongue; the tongue consists of an inner support structure and an outer contact layer; the inner support structure is a flexible substrate with shape memory alloy wires embedded in a mesh arrangement, the shape memory alloy wires having a diameter of 0.05-0.3mm, a mesh spacing of 2-8mm, and a mesh geometry of hexagon, rhombus, or orthogonal rectangle; the outer contact layer is a temperature-sensitive polymer coating with a Tg set between 32-38℃ and a thickness of 0.1-0.5mm; the tongue is detachably connected to the upper part of the shoe body via a snap-on connector or a magnetic connector.

[0008] According to the present invention, the shape memory alloy wire is made of nickel-titanium based alloy with a nickel content of 49-51 at%. After cold drawing, it undergoes aging heat treatment at 450-550℃ for 10-60 minutes to obtain a stable martensitic transformation temperature range. The martensitic transformation initiation temperature is set at 28-34℃, and the austenitic transformation end temperature is set at 36-42℃. This ensures that when the human foot is at rest (approximately 32℃), the shape memory alloy wire is in the austenitic phase, maintaining the initial preset curvature. When the foot temperature rises above 36℃ due to exercise, swelling, or local congestion, the alloy wire enters the martensitic phase and undergoes reversible deformation, reducing the overall curvature of the shoe tongue and releasing pressure on the instep. When the temperature drops below 34℃, the alloy wire returns to the austenitic phase and re-presents the initial support shape.

[0009] The flexible substrate is a polyurethane elastomer film with a Shore A hardness of 60-85 and a thickness of 0.3-1.2 mm. The shape memory alloy wire is fixed to the surface of the flexible substrate by laser micro-welding or conductive adhesive bonding to form a continuously conductive mesh circuit structure, which facilitates the subsequent integration of temperature sensing or low-voltage driving functions.

[0010] The temperature-sensitive polymer is a blend of poly(N-isopropylacrylamide) and polyurethane, wherein the mass fraction of poly(N-isopropylacrylamide) is 15%-40%, and the remainder is thermoplastic polyurethane. The blend is formed into a film by solution casting, with N,N-dimethylformamide and deionized water mixed in a volume ratio of 70:30 to 90:10, and the solid content is 8%-15%. After film formation, it is vacuum dried at 60-80°C for 12-24 hours to obtain a temperature-responsive outer contact layer.

[0011] The surface of the temperature-sensitive polymer coating has a microporous structure with a pore size of 10-100 μm and a porosity of 20%-50%, which is achieved by adding a soluble porogen before film formation. The porogen is polyethylene glycol (molecular weight of 4000-20000) or sodium chloride microparticles, and the amount added is 5%-20% of the total polymer mass. After film formation and drying, the coating is immersed in deionized water for 2-6 hours to dissolve and remove the porogen, forming a through-pore network, which enhances breathability and sweat wicking ability.

[0012] The detachable connection structure of the shoe tongue includes convex buckles on both sides of the bottom of the shoe tongue and concave grooves on the inside of the shoe tongue opening; the convex buckles are made of polyoxymethylene, with a trapezoidal or semi-circular cross-section, a height of 2-5mm, and a width of 3-7mm; the inner wall of the concave groove is provided with a silicone rubber cushioning pad with a thickness of 0.5-1.5mm, which is used to absorb impact vibration during walking and prevent the buckles from loosening.

[0013] In other embodiments, the detachable connection structure is a magnetic component, including an array of neodymium iron boron permanent magnets embedded in the bottom of the shoe tongue and a soft magnetic stainless steel sheet embedded in the corresponding position of the shoe tongue opening; the permanent magnets are cylindrical or square, with dimensions of 2mm×2mm×1-5mm×5mm×3mm, and the surface is covered with an epoxy resin insulating layer with a thickness of 0.1-0.3mm; the soft magnetic stainless steel sheet has a thickness of 0.3-1.0mm, and the surface is sandblasted to increase the coefficient of friction and prevent slippage.

[0014] The tongue has a trapezoidal shape with an upper edge width of 40-70mm, a lower edge width of 25-50mm, and a height of 50-90mm. Its initial preset curvature is determined by the anatomical data of the instep, with a radius of curvature of 80-150mm. This curvature is solidified by applying mold constraints during the pre-deformation stage of the shape memory alloy wire and performing a shaping heat treatment at 400-500℃ for 30-90 minutes.

[0015] The shape memory alloy mesh structure is densely arranged in the middle area of ​​the shoe tongue, with the mesh spacing reduced to 1-3mm, to enhance local support and deformation response sensitivity in high-pressure areas of the dorsum of the foot (such as the navicular bone prominence); while it is sparsely arranged in the upper and lower edge areas of the shoe tongue, with the mesh spacing increased to 6-10mm, to reduce edge stiffness and avoid compressing the skin in front of the ankle.

[0016] An intermediate buffer layer is provided between the outer layer of the temperature-sensitive polymer and the inner supporting structure. The intermediate buffer layer is an open-cell polyurethane foam with a density of 80-150 kg / m³. 3 The thickness is 1-3mm; the buffer layer is bonded to the inner and outer layers by hot-pressing composite process, with a hot-pressing temperature of 100-130℃, a pressure of 0.2-0.5MPa, and a time of 30-120s.

[0017] The back of the shoe tongue (i.e., the side facing the instep) is provided with biomechanical guiding patterns. These patterns are formed by laser engraving or molding, with a depth of 0.2-0.8mm. The pattern direction is designed according to the distribution of the dorsalis fascia tension line, including longitudinal main patterns and transverse auxiliary patterns. The main patterns extend along the axis of the second metatarsal bone, and the auxiliary patterns are distributed radially in the medial cuneiform and navicular bone regions to guide the redistribution of local tissue stress and reduce shear force concentration.

[0018] The shape memory alloy wire is coated with a biocompatible insulating coating, which is parylene or medical-grade silicone rubber with a thickness of 5-20 μm. The coating is formed by vapor deposition or dip coating curing process to prevent metal ion precipitation and improve corrosion resistance.

[0019] The shoe tongue can be matched with a variety of replacement models with different initial curvatures, which users can choose according to the recovery stage or foot condition; the connection interface of each shoe tongue model is kept consistent to ensure compatibility with the same shoe body; the curvature radius of the replacement models covers a range of 60-200mm to adapt to different clinical needs from severe swelling to complete swelling reduction.

[0020] The outer surface of the temperature-sensitive polymer is treated with plasma using oxygen or argon as the treatment gas, with a power of 50-150W and a treatment time of 30-180s, to increase surface energy, enhance affinity with sweat, and improve the adhesion of the antibacterial coating. After treatment, an antibacterial solution containing silver ions or chitosan can be sprayed on, with a solid content of 0.5%-3%, and after drying, a nanoscale antibacterial film is formed.

[0021] The present invention also provides a method for preparing the above-mentioned orthotic shoe material with a detachable tongue, comprising the following steps: S10: Preparation of the inner support structure—Ni-titanium alloy wire is cold-drawn to a target diameter of 0.05-0.3 mm through multiple passes, and then subjected to aging heat treatment at 450-550℃ for 10-60 min to obtain a shape memory alloy wire with a predetermined phase transformation temperature; the alloy wire is woven or laser-cut into a mesh structure according to a preset grid pattern, and fixed to a polyurethane elastomer film by micro-welding to form the inner support structure; S20: Prepare the intermediate buffer layer (if used) - cut the open-cell polyurethane foam into the same outline as the inner support structure, and control the thickness to 1-3mm. S30: Preparation of the outer contact layer—Dissolve poly(N-isopropylacrylamide) and thermoplastic polyurethane in a mass ratio of 15:85 to 40:60 in a mixed solvent of N,N-dimethylformamide and deionized water, add 5%-20% polyethylene glycol pore-forming agent, stir evenly, and then cast onto a release film. Control the doctor blade gap at 0.2-0.6 mm, level at room temperature for 30 min, and then vacuum dry at 60-80℃ for 12-24 hours to obtain a temperature-sensitive polymer film; S40: Composite molding - The inner support structure, the intermediate buffer layer (if any) and the outer contact layer are stacked in sequence, placed in a hot press, and hot-pressed for 30-120 seconds at 100-130℃ and 0.2-0.5MPa to make each layer firmly bonded. S50: Post-processing - Laser engraving of biomechanical guiding patterns on the composite tongue to a depth of 0.2-0.8mm; followed by plasma surface treatment with parameters of oxygen atmosphere, power 50-150W, and time 30-180s; S60: Assembly connectors - Polyoxymethylene buckles or neodymium iron boron permanent magnets are embedded on both sides of the bottom of the shoe tongue, and slots or soft magnetic stainless steel sheets are installed at the corresponding positions of the shoe tongue opening to complete the integration of the detachable structure.

[0022] The tongue material prepared by the above method has temperature-responsive deformation capability, detachability, biomechanical adaptability and good hygiene maintenance properties, which solves the problems of traditional orthotic tongues being unable to adapt to foot swelling or shape changes during activity, and being prone to compression or insufficient fit when worn for a long time.

[0023] In step S10, during the cold drawing process of the nickel-titanium alloy wire, the deformation amount of each pass is controlled at 8%-15%, the intermediate annealing temperature is 500-600℃, and the holding time is 5-15 minutes to prevent breakage and regulate the grain size.

[0024] In step S30, the volume ratio of N,N-dimethylformamide to deionized water in the mixed solvent is 70:30 to 90:10, and the total solid content of the polymer is 8%-15%.

[0025] In step S40, a hot melt adhesive film is coated onto each interface before hot pressing. The hot melt adhesive is an ethylene-vinyl acetate copolymer with a melt index of 10-30 g / 10 min, a melting point of 80-110 °C, and a coating amount of 10-30 g / m. 2 .

[0026] In step S50, the laser engraving uses a CO2 laser with a wavelength of 10.6μm, a power of 10-30W, and a scanning speed of 200-500mm / s.

[0027] In step S60, the neodymium iron boron permanent magnet is coated with epoxy resin before embedding. The coating process is vacuum impregnation followed by curing at 80°C for 2 hours.

[0028] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention provides an orthotic shoe, comprising a sole, an upper, and a detachable tongue as described in any embodiment of the first aspect; the tongue area of ​​the upper is provided with a connection interface matching the tongue; the sole has a built-in arch support module, the hardness of which is designed in coordination with the initial support stiffness of the tongue to form an overall biomechanical orthotic system.

[0029] 2. The corrective shoe of the present invention combines the temperature-responsive deformation of the shoe tongue with the static support of the sole to dynamically adjust the pressure distribution on the instep during the gait cycle, avoid the formation of local high pressure points, and support multiple application scenarios such as postoperative rehabilitation, sports protection and chronic foot disease management. Detailed Implementation

[0030] This invention provides an orthopedic shoe with a detachable tongue, the overall structure of which includes a shoe body and a detachable tongue. The tongue is detachably connected to the upper part of the shoe body via a connecting structure. The connecting structure can be a snap-on type or a magnetic type, wherein the snap-on connecting structure includes convex snaps on both sides of the bottom of the tongue and concave slots on the inside of the tongue opening of the shoe body; the magnetic connecting structure includes a neodymium iron boron permanent magnet array embedded in the bottom of the tongue and a soft magnetic stainless steel sheet embedded in the corresponding position of the tongue opening of the shoe body.

[0031] The technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples, so as to ensure that those skilled in the art can fully understand and implement the present invention.

[0032] Example 1: The shoe tongue is connected by a snap-on design; the shape memory alloy wire has a diameter of 0.18 mm (nickel-titanium alloy); the mesh spacing is 5 mm (hexagonal); the temperature-sensitive polymer coating thickness is 0.3 mm (Tg 35℃); the flexible substrate thickness is 0.7 mm; there is no intermediate cushioning layer; Manufacturing process: Inner support structure preparation → Outer contact layer preparation → Composite molding → Post-processing → Assembly connectors → Finished product.

[0033] Example 2: The shoe tongue is magnetically connected (neodymium iron boron permanent magnet + soft magnetic stainless steel sheet), and the rest of the formula and process are the same as in Example 1; Preparation process: Same as in Example 1 (with replacement of the connecting structure).

[0034] Example 3: The shape memory alloy wire has a diameter of 0.05 mm, and the rest of the formula and process are the same as in Example 1; Preparation process: Same as in Example 1 (alloy wire parameters adjusted).

[0035] Example 4: The shape memory alloy wire has a diameter of 0.3 mm, and the rest of the formula and process are the same as in Example 1; Preparation process: Same as in Example 1 (alloy wire parameters adjusted).

[0036] Example 5: The temperature-sensitive polymer coating thickness is 0.1 mm, and the rest of the formulation and process are the same as in Example 1; Preparation process: Same as in Example 1 (coating thickness adjustment).

[0037] Example 6: The thickness of the temperature-sensitive polymer coating is 0.5 mm, and the rest of the formulation and process are the same as in Example 1; Preparation process: Same as in Example 1 (coating thickness adjustment).

[0038] Example 7: An intermediate buffer layer (polyurethane foam, 2mm thick) is added; the rest of the formulation and process are the same as in Example 1. Preparation process: Same as in Example 1 (with the addition of a buffer layer composite step).

[0039] Example 8: The back of the shoe tongue is provided with biomechanical guiding patterns (0.5mm deep), and the rest of the formula and process are the same as in Example 1; Preparation process: Same as Example 1 (with the addition of a texture engraving step).

[0040] Comparative Example 1: The tongue is fixedly connected to the shoe body; there is no shape memory alloy mesh; the outer layer is a regular polyurethane coating; the rest of the process is the same as in Example 1; Manufacturing process: integral molding of the shoe tongue → fixing it to the shoe body → finished product.

[0041] Comparative Example 2: The shoe tongue is connected by a snap fastener; it has a shape memory alloy mesh; it has no temperature-sensitive polymer coating; the rest of the process is the same as in Example 1; Manufacturing process: Inner support structure preparation → Assembly of connectors → Finished product.

[0042] Test method: Adaptive performance testing: Measure static compression rebound rate at 37℃, deformation at 40℃, and response / recovery time; evaluate temperature response sensitivity.

[0043] Practicality and comfort testing: Testing the weight and ease of disassembly of the shoe tongue; assessing the uniformity of pressure on the instep through pressure sensors; testing breathability and wearing comfort.

[0044] Structural performance testing: Verify the stability of the connection structure; assess the decline in support after long-term use; test the biocompatibility of materials.

[0045] The test data comparisons are shown in Table 1 and Table 2.

[0046] Table 1. Comparison of compression rebound rate at 37℃, deformation at 40℃, and deformation response time. Test Project Compression rebound rate at 37℃ (%) Deformation at 40℃ (%) Deformation response time (s) Example 1 75 18 80 Example 2 74 17 85 Example 3 72 22 70 Example 4 78 13 90 Example 5 73 19 75 Example 6 76 16 88 Example 7 80 15 95 Example 8 75 17 82 Comparative Example 1 55 0 - Comparative Example 2 68 8 180 Table 2 Comparison of Recovery Time, Tongue Weight, Pressure Uniformity, and Ease of Removal Test Project Recovery time (s) Shoe tongue weight (g) Pressure uniformity Ease of disassembly Example 1 150 14 excellent good Example 2 160 16 excellent excellent Example 3 140 8 good good Example 4 170 20 good good Example 5 145 12 good good Example 6 155 17 excellent good Example 7 165 19 excellent good Example 8 152 15 excellent good Comparative Example 1 - 25 Difference Not feasible Comparative Example 2 240 12 generally good Examples 1-8 exhibit temperature-responsive deformation (deformation 13%-22%) and excellent pressure uniformity, far superior to the comparative examples. Comparative example 1 lacks adaptive function and is not detachable, while comparative example 2 has a sluggish temperature response, demonstrating that detachability + shape memory alloy + temperature-sensitive polymer is the key to efficient adaptation.

[0047] The diameter of the alloy wire is reduced (Example 4→1→3), resulting in increased deformation and reduced weight; the temperature-sensitive polymer coating is thickened (Example 5→1→6), improving comfort and pressure uniformity; the magnetic connection (Example 2) makes disassembly easier, and the buffer layer (Example 7) provides better shock absorption.

[0048] The shoe features a detachable tongue for easy cleaning and replacement; temperature responsiveness adapts to foot swelling and activity changes; even pressure distribution avoids discomfort; multiple parameter combinations are available to suit different orthodontic needs; and it is lightweight and comfortable to wear.

[0049] Compared to traditional fixed tongues (Comparative Example 1), the compression rebound rate of the embodiment is increased by 36%, and the pressure uniformity is significantly optimized; compared to non-temperature-sensitive coatings (Comparative Example 2), the deformation is increased by 112%, and the response time is shortened by 54%, solving the industry problem of poor fit and discomfort of traditional orthotic shoes.

[0050] In summary, the corrective shoe of the present invention, through the collaborative design of multiple components, can achieve adaptive support, convenient disassembly and comfortable wearing with different parameter combinations, and is suitable for foot correction and rehabilitation scenarios.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. 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 corrective shoe with a detachable tongue, characterized in that, Includes the shoe body and a detachable tongue; The shoe tongue consists of an inner support structure and an outer contact layer; The inner support structure is a flexible substrate in which shape memory alloy wires are embedded in a mesh-like arrangement. The outer contact layer is a temperature-sensitive polymer coating with a Tg of 32-38℃ and a thickness of 0.1-0.5mm; The tongue is detachably connected to the upper part of the shoe body via a snap-on connector or a magnetic connector.

2. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, The shape memory alloy wire has a diameter of 0.05-0.3 mm, a grid spacing of 2-8 mm, and a grid geometry of hexagon, rhombus, or orthogonal rectangle.

3. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, The shape memory alloy wire is a nickel-titanium based alloy with a nickel content of 49-51 at%. After cold drawing, it is subjected to aging heat treatment at 450-550℃ for 10-60 min. The martensitic transformation initiation temperature is 28-34℃, and the austenitic transformation end temperature is 36-42℃.

4. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, The flexible substrate is a polyurethane elastomer film with a Shore A hardness of 60-85 and a thickness of 0.3-1.2 mm; the shape memory alloy wire is fixed to the surface of the flexible substrate by laser micro-welding or conductive adhesive bonding.

5. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, The temperature-sensitive polymer is a blend of poly(N-isopropylacrylamide) and thermoplastic polyurethane, wherein the mass fraction of poly(N-isopropylacrylamide) is 15%-40%; the surface of the temperature-sensitive polymer coating has a microporous structure.

6. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, The snap-fit ​​connector includes convex snaps on both sides of the bottom of the shoe tongue and concave slots on the inside of the shoe tongue opening; the convex snaps are made of polyoxymethylene, with a trapezoidal or semi-circular cross-section, a height of 2-5mm, and a width of 3-7mm; the inner wall of the concave slot is provided with a silicone rubber cushioning pad with a thickness of 0.5-1.5mm.

7. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, The magnetic connection assembly includes an array of neodymium iron boron permanent magnets embedded in the bottom of the shoe tongue and a soft magnetic stainless steel sheet embedded in the corresponding position of the shoe tongue opening; the neodymium iron boron permanent magnets are cylindrical or square, with dimensions of 2mm×2mm×1-5mm×5mm×3mm, and the surface is covered with an epoxy resin insulating layer with a thickness of 0.1-0.3mm; the soft magnetic stainless steel sheet has a thickness of 0.3-1.0mm.

8. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, The shoe tongue has a trapezoidal outline, with an upper edge width of 40-70mm, a lower edge width of 25-50mm, and a height of 50-90mm; the initial preset curvature radius is 80-150mm.

9. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, The mesh spacing in the middle area of ​​the shoe tongue is 1-3mm, and the mesh spacing in the upper and lower edge areas is 6-10mm.

10. The orthotic shoe with a detachable tongue according to claim 1, characterized in that, An intermediate buffer layer is provided between the outer contact layer and the inner support structure. The intermediate buffer layer is an open-cell polyurethane foam with a density of 80-150 kg / m³. 3 The thickness is 1-3mm.