Footwear with heel shape-keeper

Abstract

Conventionally, hands-free footwear having a spring structure at the heel is known. To provide footwear which has a fit feeling and can be quickly and easily worn in a hands-free manner without giving a user a sense of incongruity due to the presence of a spring structure, and to provide a method of manufacturing the same.SOLUTION: The shape retainer 6 as the spring structure includes a heel shape retaining member 10 arranged at the uppermost part of the heel of the footwear, two foot members 20 arranged at the lowermost part of the instep material of the footwear, and two connecting members 30 formed of a superelastic alloy for connecting the heel shape retaining member 10 and the foot members 20. The foot member 20 has a foot member sewing portion 22 which is formed in a substantially triangular shape so as to withstand the force from the connecting member 30 and which is formed to be particularly thin so as to be sewn to the instep member by a sewing machine. One set of the mold holders 6 can be manufactured at a time through an injection molding process using a mold.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention belongs to the field of footwear manufacturing, and specifically relates to footwear having a heel support. [Background technology]

[0002] In recent years, there has been an increasing demand for hands-free footwear that can be quickly put on without using hands or a shoehorn. In particular, the elderly, people with disabilities, and people working in specialized occupations desire footwear that is easy to put on and convenient to wear. Technologies used in hands-free footwear include those that involve modifying the shape of the heel portion and its heel counter, and those that involve adding a spring structure to the heel portion of the footwear to restore the shape of the heel portion. In the case of footwear that has a spring structure in the heel portion of the footwear, how easily the spring structure can be implemented in the footwear has a significant impact on the manufacturing process of the footwear and, ultimately, on the cost.

[0003] Regarding the implementation of spring structures in footwear, for example, Patent Document 1 discloses a wire spring formed by bending an elastic metal wire, in which the wire spring, excluding both ends, is sandwiched between the outer and inner surfaces of the shoe instep, the center portion folded back into a U-shape along the rear opening edge of the shoe opening, the left and right sides folded downward in an arc, and both ends passing through the rear surface of the sole plate via notched grooves and through holes, with the left and right ends further bent backward and attached to mounting holes. Patent Document 2 discloses a wire rod made of an elastically deformable material, with one end of the wire rod fixed to the lower rear portion of the upper on the medial side of the foot. The other end of the wire rod is fixed to the lower rear portion of the upper on the lateral side of the foot. Each end of the wire rod is bent forward and inserted into a pouch fixed to the upper by adhesive or manufacturing process, and is fixed to the pouch. Patent Document 3 discloses a mounting method having a deformable element attached to a rigid base, the deformable element being disposed between an inner layer and an outer layer and having an outward-facing peg for positioning the deformable element from at least one of the deformable element and the base. The deformable element is first coupled to anchors, which are then coupled to anchor receiving parts. Each anchor receiving part includes a pair of pins. The mounting method then discloses a method in which the deformable element is secured to the base by a snap-fit ​​effect. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-139502 [Patent Document 2] Utility Model Registration No. 3239159 [Patent Document 3] Special Publication No. 2022-516464 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the method of Patent Document 1 has problems such as water intrusion and a lack of aesthetic appeal, since both ends of the wire penetrate the back of the sole plate via notched grooves and through-holes, and the left and right ends are bent backward and attached to the mounting holes. Furthermore, the method of Patent Document 2 has each end of the wire bent forward and inserted into a pouch fixed to the upper by gluing or sewing, and then fixed to the pouch, which causes problems such as stress concentration at the bent portion, a small spring constant, and a lack of safety as the wire may slip out of the pouch. Furthermore, the mounting method of Patent Document 3 requires a large number of steps, such as attaching the deformable element to the anchor, fitting the anchor into the anchor receiver, and attaching the peg to the footwear, as well as a special structure for mounting the spring structure to the footwear.

[0006] The inventors conducted extensive research to solve these problems, and as a result, they came up with a very simple structure in which the spring structure is made up of a heel-retaining member placed at the top of the heel part of the footwear, a foot member placed at the bottom of the upper material of the footwear, and a connecting member made of a superelastic alloy that connects the heel-retaining member and the foot member.This makes it easy to implement the spring structure in the heel of the footwear, simplifies the manufacturing process, and achieves significant cost reductions. [Means for solving the problem]

[0007] Footwear having a shape retaining device at the heel of the footwear for hands-free wearing, the shape retaining device comprising: The footwear comprises a heel-supporting member located at the top of the heel portion of the footwear, two foot members located at the bottom of the upper material of the footwear, and two connecting members formed of a superelastic alloy that connect the heel-supporting member and the foot members, the heel-supporting member having two connecting member insertion holes for inserting the connecting members, and each of the foot members having one connecting member insertion hole for inserting a connecting member, the heel-supporting member having a small thickness to accommodate the connecting member insertion holes, and the central part being as thin as possible and formed with an inwardly concave shape, the foot members being thin so as not to cause discomfort to the user's feet and being formed in a roughly triangular shape so as to withstand the force from the connecting members, and the foot members having an especially thin foot member sewing section for sewing to the upper material with a sewing machine. This allows the spring structure to have a very simple configuration, making it easy to implement the spring structure in footwear, simplifying the manufacturing process, and achieving significant cost reductions.

[0008] In the footwear, the insertion hole for the connecting member of the foot member is inclined obliquely backward, and the approximately triangular shape of the foot member has a long front side and a short rear side, with the ratio of the lengths being approximately 2:1. This satisfies the three requirements for the leg member: 1. It must not break even when a strong force is applied diagonally upwards towards the front, 2. It must be thin and small so as not to cause discomfort to the user, and 3. It must have a connecting member insertion hole that is inclined diagonally towards the rear.

[0009] In the above-mentioned footwear, the central part of the heel support member has a shape that imitates the shape of the heel of the footwear, and a portion with connecting member insertion holes on the left and right extends from the central part of the heel support member toward the foot member, and can be easily deformed via the connecting member according to the attachment distance between the left and right foot members, and the width of the arc-shaped V-shape formed by this deformation is formed slightly narrower than the width of the heel of the foot. This allows the user to feel a tight fit while preventing the shoes from coming off during natural walking.In addition, the overall beauty and design of the footwear is maintained without significantly changing the appearance of the footwear.

[0010] In the above-mentioned footwear, the central part of the heel support member is configured to always receive pressure from the heel of the foot diagonally downward and outward, and when pressure is applied from the heel of the foot, the connecting member is formed to bend in an arc outward. As a result, when a user puts on the footwear, the force from the user's foot to the connecting member always acts downward and outward on the opening, and the force from the foot to the connecting member does not act inward on the opening, so there is no risk of the heel of the footwear being crushed toward the opening.

[0011] In the above-mentioned footwear, when the heel support member receives pressure from the heel of the foot, the connecting member curves in an arc diagonally downward outward, so that the upper end of the heel of the footwear extends farther rearward than the rearmost part of the outsole of the footwear, widening the opening. This widens the opening, allowing for quick, hands-free putting on. When the heel of the foot slides into the footwear, the recovery force of the connecting member causes the heel of the footwear to return to its normal state, and the arc-shaped V-shaped heel of the footwear formed by the heel support member and the connecting member fits snugly around the heel of the user's foot, making it less likely to slip off.

[0012] In the above-mentioned footwear, the heel support member and the foot member are formed from TPU (thermoplastic polyurethane), and the connecting member is a superelastic alloy made of Nitinol. As a result, the heel support member and the foot member can be made elastic and thin, giving the user a comfortable fit and being durable. In addition, the connecting member has strong elastic recovery properties, so that the heel of the footwear is always biased sufficiently, and when the user puts on the footwear, the rebound force allows the crushed heel to instantly return to its original state when the user's foot is inserted into the footwear.

[0013] In the above-mentioned footwear, when the shape retainer is attached to the heel of the footwear, a force is controlled to act in a direction that prevents the connecting member from slipping out of the connecting insertion holes of the heel shape retainer and the foot member. This provides safe footwear in which the connecting member does not slip out of the connecting insertion holes of the heel-shape member and the foot member even if the force of the user's entire body weight is applied to the shape retainer when the user puts on the footwear.

[0014] In the above-mentioned footwear, the thickness of the foot member is approximately 4 mm at the connection part with the connecting member, and gradually becomes thinner from the connection part toward the periphery, being approximately 2 mm at the farthest part, and even thinner at approximately 1 mm at the foot member sewn part. This makes it possible to provide safe footwear that does not give the user any discomfort due to the presence of the shape retainer and that will not break even under the pressure of the user's foot.

[0015] This method for manufacturing footwear with heel retainers includes the steps of using a mold to manufacture one set of heel retainers at a time through an injection molding process, attaching a protective layer to the heel retainers, and sewing the foot member sewing portion of the foot member to the bottom of the upper material by machine sewing with sewing thread. This allows for the highly efficient manufacture of a shape-retaining device having a spring structure, and also allows the shape-retaining device to be mounted on footwear through a very simple process, thereby improving productivity and significantly reducing manufacturing costs.

[0016] In the above-mentioned method for manufacturing footwear, the mold is made of mold steel of a chromium-nickel-molybdenum alloy. This makes the mold more durable and stable, ensuring precision and consistency of the product during the manufacturing process.

[0017] In the above-described method for manufacturing footwear, the heel-retaining member and the connecting member are integrally formed by an injection molding process using a mold. This strengthens the joining strength between the heel-holding member and the connecting member, and also eliminates the step of inserting the connecting member into the connecting insertion hole of the heel-holding member.

[0018] In the above-mentioned method for manufacturing footwear, the mold is provided with a plurality of positioning points for manufacturing connecting members of different lengths. This allows for different lengths of connecting members to be made and for use with different sizes of footwear.

[0019] In the above-mentioned footwear manufacturing method, the mold is equipped with two needles for forming a connecting member insertion hole of the foot member, and the needles can be replaced with needles of different thickness and / or length depending on the size of the connecting member insertion hole. This allows accurate drilling of connecting member insertion holes that are inclined diagonally backward in the leg members. Also, by changing to needles of different thicknesses and / or lengths, connecting member insertion holes of different sizes and / or lengths can be drilled. [Effects of the Invention]

[0020] As described above, the present invention provides footwear that fits well, is safe, and can be put on quickly and easily in a hands-free manner without causing the user any discomfort due to the presence of a shape-retaining device. Furthermore, the present invention makes it possible to make the shape-retaining device, which is a spring structure, a simple spring structure that is easy to install in footwear, and since the footwear does not need to have a special structure for installing the shape-retaining device, the manufacturing process for footwear with a shape-retaining device is simplified, made more efficient, and allows for significant cost reductions. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram showing the overall structure of a shoe having a heel shape retainer 6 according to this embodiment. [Figure 2] FIG. 2 is an overall configuration diagram of a shape-retaining tool 6. [Figure 3] FIG. 1 is a perspective view of an embodiment in which a shape retaining device 6 is mounted on a shoe. [Figure 4] 1A and 1B show an embodiment of a heel support member 10, in which (a) is a front view and (b) is a perspective view. [Figure 5] 10 is an explanatory diagram showing deformation of the shape retainer 6 due to pressure from the user's foot. FIG. [Figure 6] A generally triangular embodiment of the leg member 20 is shown. [Figure 7] 1 shows an embodiment of a leg member 20, where (a) is a front view and (b) is a cross-sectional view taken along the line A-A'. [Figure 8] 1 shows the manufacturing process steps for footwear with a shape retainer 6. [Figure 9] 1 shows a mold 50 of one embodiment used to manufacture the mold retainer 6. [Figure 10] 1 is a schematic diagram for explaining how the shape-retaining device 6 is attached to the heel part 40 of the shoe. FIG. [Figure 11]1 is an explanatory diagram of the restoring action of the shape-retaining device 6, in which (a) shows a state in which no pressure is applied to the top of the heel portion 40 of the shoe, (b) shows a state in which the heel of the user's foot abuts against the heel portion 40 of the shoe and presses down slightly when putting on the shoe, (c) shows a state in which the user presses down on the heel portion 40 of the shoe with the heel of the user to insert the heel into the shoe, causing the heel portion of the shoe to be crushed, and (d) shows a state in which the user has inserted the heel into the shoe and the heel portion 40 of the shoe is released from the pressure of the heel of the user's foot. DETAILED DESCRIPTION OF THE INVENTION

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention can be embodied in various forms. Below, an embodiment of the present invention applied to a shoe will be described. Naturally, the present invention can also be applied to footwear other than shoes. FIG. 1 shows a typical shape of a shoe. A shoe is composed of an upper 2, a midsole 3, an outsole 4, and an opening 5. In the following description, "shoe" refers to a single shoe, "upper 2" refers to the upper part of the shoe excluding the sole, "upper material" refers to the material of the upper 2 of the shoe, and "lining" refers to the material used inside the shoe. Upper materials typically include leather, synthetic leather, mesh, and synthetic fabric. Lining materials typically include rubber, EVA (ethylene vinyl acetate copolymer), and PU (polyurethane).

[0023] As shown in Figure 1, footwear with a shoe shape retainer of the present invention has a shoe heel shape retainer 6 with a spring structure attached to the heel portion 40 of the shoe. When a user puts on shoes, the heel portion 40 of the shoe bends in response to pressure from the user's foot, widening the shoe opening 5 and allowing the user to put on the shoes quickly and easily without using their hands.

[0024] First, we will explain the shoe heel shape retainer 6 of the present invention. Figure 2 shows the overall configuration of the shape retainer 6. The shape retainer 6 is composed of a heel shape member 10 attached to the top center of the shoe heel, a foot member 20 attached to the bottom of the upper material of the shoe heel, and a connecting member 30 connecting the heel shape member 10 and the foot member 20. The foot member 20 is composed of two foot members 20: a left foot member 20L and a right foot member 20R. Therefore, the connecting member 30 is also composed of two connecting members 30: a left connecting member 30L connecting the heel shape member 10 to the left foot member 20L and a right connecting member 30R connecting the heel shape member 10 to the right foot member 20R.

[0025] Two holes are drilled in the heel-supporting member 10: a left connecting member insertion hole 11L for inserting the left connecting member 30L and a right connecting member insertion hole 11R for inserting the right connecting member 30R. Also, a left connecting member insertion hole 21L for inserting the left connecting member 30L is drilled in the left foot member 20L, and a right connecting member insertion hole 21R for inserting the right connecting member 30R.

[0026] Materials for the heel-supporting member 10 include TPU (Thermoplastic Polyurethane), TPE (Thermoplastic Elastomer), silicone, elastomer, neoprene, etc., but TPU is preferred in terms of abrasion resistance, oil resistance, chemical resistance, elastic recovery, and flex resistance. Also, TPU is preferred as the material for the foot member 20 from the same viewpoint.

[0027] The connecting member 30 is made of a superelastic alloy. A superelastic alloy is an alloy that, even if deformed by a large strain, returns to its original shape when the deforming force is removed. Examples of superelastic alloys include Nitinol, an alloy of nickel and titanium, cobalt-chromium alloy, copper-aluminum-nickel alloy (Cu-Al-Ni), and silver-cadmium alloy, with Nitinol being preferred. Nitinol is an alloy of nickel and titanium that possesses superelasticity and shape memory properties. It retains a fixed shape at low temperatures and returns to its original shape when heated. This property allows it to be used as a memory alloy in medical devices (stents, vascular filters, etc.), eyeglass frames, dental wires, robotics, the aerospace industry, and more.

[0028] Figure 3 is a perspective view of one embodiment of a shoe heel retainer 6 mounted on a shoe. The heel retainer 10 is attached to the top center of the shoe heel portion 40. The left foot member 20L is attached to the bottom left side of the shoe upper. The left connecting member 30L is then inserted into the left connecting member insertion hole 11L of the heel retainer 10 and the left connecting member insertion hole 21L of the left foot member 20L to connect them. At this time, in order to maintain the shape of the shoe heel portion 40, it is preferable that the left connecting member 30L be long enough to bend slightly so that the upward restoring force of the superelastic force of the left connecting member 30L constantly applies an upward bias to the heel portion.

[0029] Similarly, the right foot member 20R is attached to the bottom right side of the shoe upper. The right connecting member 30R is then inserted into the right connecting member insertion hole 11R of the heel-shape retaining member 10 and the right connecting member insertion hole 21R of the right foot member 20R to connect them. At this time, in order to maintain the shape of the heel portion 40 of the shoe, it is preferable that the right connecting member 30R be slightly bent so that the upward restoring force of the superelastic force of the right connecting member 30R constantly applies an upward bias to the heel portion.

[0030] Heel-retaining member 10 is made of a material with elastic restoring force, such as TPU, and is formed so that it can deform from the open state shown in Figure 2 to a closed, arc-like, approximately V-shaped state as shown in Figure 3, depending on the distance between left foot member 20L and right foot member 20R attached to the bottom of the upper. The width of this arc-like, approximately V-shaped shape is formed slightly smaller than the width of the heel of the foot, and the pressure of the user when putting on the shoe causes it to expand, and when the shoe is finished, a restoring elastic force applies a bias that causes it to return to its original width. This gives the user a snug fit while preventing the shoe from coming off when walking naturally.

[0031] FIG. 4(a) is a front view of one embodiment of a heel-supporting member 10, and FIG. 4(b) is a perspective view. The heel-supporting member 10 is attached to the top center of the heel portion 40 of a shoe. One of its functions is to constantly bias the heel portion of the shoe upward using the restoring force of the superelastic alloy of the connecting member 30, thereby maintaining the shape of the heel portion 40. The heel-supporting member 10 has two connecting member insertion holes 11, a left connecting member insertion hole 11L and a right connecting member insertion hole 11R, and is shaped to fit the shape of the top center of the heel portion 40 of the shoe. It is also thin enough to avoid causing discomfort to the heel of the user's foot, and must be constructed so that it will not break even when the user's entire weight is applied to the heel-supporting member 10 via the heel of the user's foot when wearing the shoe. Therefore, in this embodiment, the heel support member 10 is made of TPU as shown in Figure 4, with both ends being slightly thick to accommodate the connecting member insertion holes 11, and the center being as thin as possible with an inwardly concave shape. However, the shape of Figure 4 is not restrictive, and any shape that can fulfill the function of the heel support member 10 is within the scope of this invention.

[0032] Another function of the heel support member 10 is to ensure that, when a user puts on the shoe, pressure from the user's foot on the connecting member 30 always acts outward and downward on the opening 5, preventing pressure from the foot from acting inward on the connecting member 30. To this end, the foot member insertion hole 21 is shaped to be inclined diagonally backward relative to the base of the foot member 20, so that the heel support member 10 ensures that pressure from the user's foot always acts outward and downward on the connecting member. That is, as shown in Figure 5, when no force is applied, the connecting member is inclined diagonally backward in a straight line as shown in A. With the heel support member 10 and foot member 20 attached to the shoe, it is inclined diagonally backward and slightly curved outward as shown in B. When pressure is applied from the user's foot, the pressure from the foot acts even more outward and downward than in A. This curvature also creates a restoring force that pushes the upper heel of the shoe upward. In other words, the upper heel of the shoe is always biased upward.

[0033] When pressure is applied from the user's foot, connecting member 30 bends outward and downward as shown by arrow A, passing through state C and then into state D. This bending causes a strong outward force to act on the highest point 41 of the heel of the shoe from connecting member 30 via heel-holding member 10, widening shoe opening 5 from the very rear of the outsole to the rear, allowing the user's heel to easily slide into the footwear. At this time, a strong diagonally upward force as shown by arrow B is also applied to foot member 20 through connecting member 30.

[0034] When the heel support member 10 and foot member 20 are attached to the shoe, a reaction force acts diagonally forward from the heel of the shoe on the heel support member 10. This force is then applied to the foot member 20 through the connecting member 30, and the foot member 20 then applies an upward reaction force. In other words, a force acts on the connecting member 30 to prevent it from slipping out of the connecting member insertion holes of the heel support member 10 and foot member 20. This is also true when pressure is applied from the user's foot, causing the connecting member 30 to bend from state C to state D. Thus, the heel support member 6 of the present invention has a self-regulating function that prevents the connecting member 30 from slipping out of the connecting member insertion holes of the heel support member 10 and foot member 20. However, because the foot member connecting hole 21 is inclined backward, if it is too shallow, it may slip out due to a force applied diagonally forward. Therefore, it is desirable to make it deeper, between 15 mm and 25 mm. This provides safe footwear that will not allow the connecting member 30 to slip out of the connecting member insertion hole and injure the user. Of course, the scope of this invention also includes methods of achieving control functions such as providing a gap expansion control structure between the heel-supporting member 10 and the foot member 20 and an expansion control structure in the heel portion of the footwear in a direction away from the heel portion.

[0035] As described above, a strong diagonally upward force is applied to the foot member 20 as indicated by arrow B. Therefore, the foot member 20 is required to have the following characteristics: 1. a shape that will not break even when this strong diagonally upward force is applied, 2. a thin and small shape so as not to cause discomfort to the user, and 3. a shape that includes a connecting member insertion hole 21 that is inclined diagonally backward. After various experiments and trial and error, the inventors have become convinced that the most suitable shape to meet these requirements is a generally triangular shape, as shown in Figure 6, in which the front portion 23 of the foot member is long and the rear portion 24 of the foot member is short, with a ratio of approximately 2:1. The generally triangular shape also includes shapes that are modified from the shape shown in Figure 6 (A) to the shapes shown in Figure 6 (D) and (C).

[0036] FIG. 7(a) is a front view of one embodiment of the foot member 20, and FIG. 7(b) is an A-A' cross-sectional view of the foot member 20. In this embodiment, the foot member 20 has a generally triangular shape with a base length of 60 mm, a front portion 23 length of 40 mm, a rear portion 24 length of 20 mm, and a height 25 of 27 mm. The connecting member insertion hole 21 has a diameter of 2 mm and a depth of 20 mm. The connecting member insertion hole 21 must be sufficiently deep, between 15 mm and 25 mm, so that the connecting member 30 will not slip out even if the connecting member 30 is bent to the "C" position. To avoid discomfort to the user's foot, the foot member is thin, measuring approximately 4 mm at the connection point with the connecting member and approximately 2 mm from the connection point toward the periphery. Since the foot member 20 is sewn to the lowermost part 43 of the upper material by a sewing machine, the foot member sewn portion 22 is particularly thin, measuring approximately 1 mm, as shown in FIG. 7(b). Even with this thin design, the generally triangular shape of the front portion 23, which is long, can adequately withstand pressure from the foot.

[0037] Next, we will explain the manufacturing method of footwear having the shape-retaining device 6 of the present invention. As described above, the shape-retaining device 6 has a very simple spring structure, so no special structure is required to attach the shape-retaining device 6 to the footwear. Therefore, the manufacturing method of footwear having the shape-retaining device 6 can be realized by simply adding the step of attaching the shape-retaining device 6 to the conventional manufacturing method of footwear.

[0038] As shown in FIG. 8, the process of attaching the shape-retaining device 6 includes the steps of S1. manufacturing the shape-retaining device 6 using a mold, S2. attaching a protective layer to the shape-retaining device 6, S3. fixing the foot member 20 to the lowermost part 43 of the upper material, S4. inserting the connecting member 30 into the connecting member insertion hole 21, and S5. attaching the heel-shape-retaining device 10 to the uppermost part of the heel part 40 of the shoe.

[0039] In step S1, the heel support 6 is manufactured using a mold, and one set of heel support 10 is manufactured at a time through an injection molding process using a mold. For example, a mold 50 as shown in FIG. 9 can be used as the mold. This mold 50 is made of a chromium-nickel-molybdenum alloy, and the titanium-nickel alloy thread that forms the connecting member 30 is directly incorporated into the heel support 10, thereby forming the heel support 10 and the connecting member 30 as a single unit. This strengthens the bond between the heel support 10 and the connecting member 30. This injection molding process makes the production process more efficient, reduces raw material waste, and significantly reduces manufacturing costs.

[0040] The mold 50 can be provided with a plurality of positioning points to obtain titanium-nickel alloy threads of different lengths, which are the connecting members 30, so that they can be applied to different sizes of shoes. As shown in Figure 9, this is achieved by controlling the length of the alloy threads, which are the connecting members 30, using a number of positioning holes 52 and positioning pins 51 that can be attached to the mold 50.

[0041] The mold 50 is equipped with a slider 53 and two needles 54 fixed thereon to form the leg member connecting holes 21. This allows the leg member connecting holes 21 to be accurately formed with a backward tilt. Also, by changing the thickness and / or length of the needles, leg member connecting holes 21 with different diameters and / or depths can be drilled.

[0042] In the step of attaching a protective layer to the shape retainer 6, the heel retainer 10, foot member 20, and connecting member 30 are covered with cushioning material or the like to protect the shape retainer 6 and improve comfort and safety for the user. For example, to prevent the heel retainer 10 from causing discomfort to the heel of the user, the entire heel retainer 10 is wrapped in fabric lined with a 2 mm thick cushioning material, and the connecting member 30 is covered with nonwoven fabric or the like to prevent it from directly touching the user's foot (not shown). Of course, methods such as attaching cushioning material to the top of the heel portion or attaching cushioning material to the heel portion of the connecting member 30 during advance upper manufacturing are also within the scope of this invention.

[0043] In the step of S3, the foot member 20 is fixed to the lowermost part 43 of the upper material by sewing the foot member sewn part 22 and the upper material together with sewing thread at the lowermost part 43 of the heel part of the upper material. Figure 10 is a schematic diagram for explaining the state in which the shoe heel shape retainer 6 is attached to the heel part 40 of the shoe, and shows the state in which all of the shoe soles have been removed.

[0044] S4. In the step of inserting the connecting member 30 into the connecting member insertion hole 21, the connecting member 30, which is integrally formed with the heel support member 10 through an injection molding process using a mold, is inserted into the connecting member insertion hole 21 of the foot member 20.

[0045] Then, in step S5, the heel support member 10 is attached to the top of the heel portion 40 of the shoe, by placing the heel support member 10 against the lock stitch and fixing it between the heel upper lining 42 of the shoe and the lining (not shown) at the top 41 in the center of the heel portion of the shoe using glue or other methods.

[0046] FIG. 11 is an explanatory diagram of the function of the shoe heel retainer 6. FIG. 11(a) shows the state in which no pressure is applied to the upper part of the heel portion 40 of the shoe. As mentioned above, the connecting member 30 made of a superelastic alloy is attached in a slightly curved state, and therefore, due to its restoring force, an upward bias is always applied to the heel retainer 10 attached to the central top part 41 of the heel portion 40 of the shoe, and the heel portion 40 of the shoe is always maintained in an upright shape. FIG. 11(b) shows the state in which the heel of the user's foot contacts the heel portion 40 of the shoe and steps forward slightly when putting on the shoe. At this time, the connecting member 30 bends more than shown in FIG. 11(a) in response to the pressure of the user's heel. Figure 11(c) shows the state in which the user presses down further on the heel portion 40 of the shoe with the heel of the user's foot to insert the heel of the foot into the shoe, causing the heel portion 40 to collapse and the connecting member 30 to bend significantly. At this time, the restoring force of the connecting member 30 increases further in accordance with the bending, and the force pushing upward on the upper part of the heel portion 40 of the shoe increases further, allowing the user to easily slide the heel of the foot into the shoe. Figure 11(d) shows the state in which, once the heel of the user's foot is inside the shoe, the pressure on the heel portion 40 of the shoe is released, and at the same time, the heel portion 40 of the shoe is restored to its original shape due to the amazing elastic recovery effect of the connecting member 30.

[0047] It should be noted that the method of attaching the heel shape retainer 6 of footwear of the present invention shown in this embodiment is not restrictive, and other methods of attachment may be adopted in accordance with the gist of the present invention. The embodiment of the present invention is not limited to the shape shown in this example, and other shapes may be adopted as long as they do not go against the gist of the present invention, which is to provide footwear with a shape-retaining device that can be quickly put on hands-free by implementing the shape-retaining device 6 without significantly changing the structure of existing footwear. [Explanation of symbols]

[0048] 1. Shoes 2. Upper 3 Midsole 4 Outsole 5 Shoe opening 6 Shoe heel retainers 10 Heel support member 11. Connecting member insertion hole 11L Left connecting member insertion hole 11R Right connecting member insertion hole 20 Foot members 20L Left leg member 20R Right foot member 21 Connecting member insertion hole 21L Left connecting member insertion hole 21R Right connecting member insertion hole 22 Leg member sewing part 23 Front 24 rear 25 height 30 Connecting member 30L Left connecting member 30R Right connecting member 40 Heel of shoe 41 Top of the heel of the shoe 42 Shoe heel upper lining 43 Lower part of heel of upper material 50 molds 51 Positioning pin 52 Stereotaxic hole 53 Slider 54 needles

Claims

1. Footwear having a shape retaining device at the heel for hands-free wearing, The shape retainer is A heel support member disposed on an upper part of the heel of the footwear; Two foot members disposed under the upper material of the footwear; two connecting members made of a superelastic alloy that connect the heel-retaining member and the foot member; The heel support member has two connecting member insertion holes into which the connecting members are inserted, Each of the leg members has one connecting member insertion hole into which the connecting member is inserted, The heel support member has a small thickness to accommodate the insertion hole of the connecting member, and the central portion is as thin as possible and is formed in a concave shape. The foot member is formed thinly so as not to cause discomfort to the user's foot, and is formed in a substantially triangular shape so as to be able to withstand the force from the connecting member, The footwear is characterized in that the foot member has a particularly thinly formed foot member sewing portion for sewing to the upper material with a sewing machine.

2. Footwear according to claim 1, characterized in that the connecting member insertion hole of the foot member is inclined diagonally backward, and the approximately triangular base of the foot member has a long front side and a short rear side, with the ratio of the lengths being approximately 2:

1.

3. Footwear according to claim 1 or 2, characterized in that the central portion of the heel-retaining member has a shape that imitates the shape of the heel of the footwear, and portions having connecting member insertion holes on the left and right sides extend from the central portion of the heel-retaining member toward the foot members, and the heel-retaining member can be easily deformed via the connecting members according to the attachment distance between the left and right foot members, and the width of the arc-shaped V-shape formed by the deformation is slightly narrower than the width of the heel of the foot.

4. 4. Footwear according to claim 1, wherein the central portion of the heel-holding member is configured to constantly receive pressure from the heel of the foot in an outward and obliquely downward direction, and the connecting member is formed so as to bend in an outward and obliquely downward direction when pressure is applied from the heel of the foot.

5. Footwear according to any one of claims 1 to 4, characterized in that when the heel-holding member receives pressure from the heel of the foot, the connecting member curves in an arc diagonally downward outward, causing the upper end of the heel portion of the footwear to extend farther rearward than the rearmost portion of the outsole, widening the opening.

6. Footwear according to any one of claims 1 to 5, characterized in that, when the shape-retaining device is attached to the heel of the footwear, a force is controlled to act in a direction that prevents the connecting member from slipping out of the connecting insertion holes of the shape-retaining member and the foot member.

7. Footwear according to any one of claims 1 to 6, characterized in that the heel support member and the foot member are formed from TPU (thermoplastic polyurethane), and the connecting member is a superelastic alloy made of Nitinol.

8. Footwear according to any one of claims 1 to 7, characterized in that the thickness of the foot member is approximately 4 mm at the connection portion with the connecting member and gradually narrows to approximately 2 mm from the connection portion toward the periphery, and the thickness of the foot member sewn portion is particularly narrow, approximately 1 mm.

9. A method for manufacturing footwear having a shape retaining device manufacturing one set of heel support at a time through an injection molding process using a mold; attaching a protective layer to the heel support; a step of sewing the foot member sewing portion to the bottom of the upper material with sewing thread by machine and fixing it; A method for manufacturing footwear having a shape-retaining device comprising:

10. 10. The method for manufacturing footwear according to claim 9, wherein the mold is made of mold steel of a chromium-nickel-molybdenum alloy.

11. 11. The method for manufacturing footwear according to claim 9 or 10, wherein the heel-retaining member and the connecting member are integrally formed by an injection molding process using the mold.

12. 12. The method for manufacturing footwear according to claim 9, wherein the mold is provided with a plurality of positioning points for manufacturing connecting members of different lengths.

13. 13. A method for manufacturing footwear according to any one of claims 9 to 12, characterized in that the mold is equipped with two needles for forming the connecting member insertion hole of the foot member, and the needles can be replaced with needles of different thicknesses and / or lengths.

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