Patent Application
20190075889
The present invention relates to a shoe upper for a shoe, in particular a sports shoe, comprising a knitted fabric, and to a method of manufacture of such a shoe upper.
Conventional shoes essentially comprise two elements: a sole and a shoe upper. Whereas a sole often consists of only one material (e.g. rubber or leather) or of only a few materials, various materials are often used in a shoe upper for different parts of the foot, in order to provide different functions. As a result, there are various individual parts. A typical shoe upper for a sports shoe may comprise more than fifteen parts. During manufacture, the assembly of these parts is particularly time-consuming and often carried out by manual labor. Moreover, such a manufacturing technique produces a large amount of waste.
In order to reduce production efforts, it is therefore known to knit a shoe upper in one piece. Knitting shoe uppers has the advantage that they can be manufactured in one piece but may still comprise various structures with a variety of characteristics. Moreover, the one piece shoe upper is already manufactured in its final shape and usually only requires to be closed in one section. This approach does not produce any waste by the final shape being cut out. Knitted shoe uppers are described in U.S. Pat. Nos. 2,147,197, 1,888,172, 5,345,638, and PCT Pub. No. WO1990/003744, for example.
U.S. Pat. No. 7,774,956 describes a shoe upper with zones of multiple properties (e.g. stretchability) by using different yarns and/or stitch patterns. Additionally, pockets, tunnels, or layered structures are manufactured by knitting. U.S. Publication No. 2011/0078921, now U.S. Pat. No. 9,149,086, describes a shoe upper in which various elements, such as e.g. the tongue or the upper edge of the heel, are manufactured by knitting.
In contrast to woven textile materials or other less elastic materials, a knitted shoe upper has considerably greater stretchability, owing to the textile structure created by intertwined stitches. It may therefore be desirable to reduce the stretchability of the knitted material for use as a shoe upper. U.S. Pat. No. 2,314,098 describes a shoe upper, certain portions of which are stiffened by the use of yarns for the textile material that contain synthetic filaments, which are heat treated so that the textile material melts and subsequently solidifies. U.S. Pub. No. 2010/0154256, now U.S. Pat. No. 8,490,299, describes a thermoplastic yarn that is melted in different regions. The use of thermoplastic yarns for knitting shoe uppers and subsequent thermal treatment for altering the properties of the material or for shaping are described in U.S. Pat. Nos. 2,314,098, 2,641,004, 2,440,393, and U.S. Pub. No. 2010/0154256, now U.S. Pat. No. 8,490,299.
Reduced stretching of a knitted shoe upper by applied structures is described in U.S. Pat. Nos. 7,637,032, 7,347,011, and 6,931,762. In U.S. Pat. No. 4,785,558, a shoe upper consists of an outer knit fabric layer and an inner knit fabric layer connected by a synthetic monofilament in order to achieve suitable elasticity and air permeability.
U.S. Pat. Nos. 7,047,668 and 4,447,967 describe shoe uppers with a polymeric outer layer manufactured in a mold and an inner layer formed of a textile material. In German Pat. No. DE102009028627, a shoe upper is reinforced by reinforcement ribs on the inside.
However, the previous solutions for limiting the stretchability of knitted shoe uppers have disadvantages. The use of thermoplastic materials alters the appearance of the knitted textile material and limits design options. The use of additionally applied structures also alters the appearance of the knitted textile material, since they are applied to the outside of the shoe upper. Moreover, the number of parts of the shoe upper and thus the manufacturing effort is increased. Applying them on the inside might cause pressure sores at the foot leading to a limitation of the design of the outside of the shoe upper. The shape of the applied structures also reduces stretchability only in certain directions.
In view of the prior art, it is therefore an object of the present invention to provide a shoe upper with knitted fabric, which overcomes the described disadvantages and which effectively limits the stretchability of the knitted fabric without the outer appearance of the knitted fabric being adversely affected.
The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings and each claim.
According to a first aspect, this problem is solved by a shoe upper for a shoe, in particular a sports shoe in accordance with claim 1. The shoe upper comprises a first portion and a second portion, which are jointly manufactured as a knitted fabric, wherein only one of the portions is reinforced by a coating of a polymer material applied to the shoe upper.
Due to the applied polymer coating, the stretchability of the knitted fabric is specifically reduced in a portion without affecting the outer appearance of the knitted fabric and without limiting the design options of the knitted fabric. Thus, the structure of the knitted fabric does not have to be altered in order to achieve its advantages such as increased air permeability. At the same time, the stretchability of the knitted fabric is effectively reduced in any desired directions of movement. The polymer coating furthermore increases the stiffness and stability of the knitted fabric.
In further embodiments, the knitted fabric is weft-knitted or warp-knitted. Flat knitted fabric has the advantage that the outline of the shoe upper is manufactured directly, without having to subsequently cut out the knitted fabric and to process it further at the edges.
According to some embodiments, the coating of a polymer material is applied to the inside of the shoe upper. Thus, the outer appearance of the knitted fabric remains unaffected by the polymer layer.
The polymer material may be applied to the shoe upper in a liquid state. In some embodiments, the polymer material has a viscosity in the range of about 15-80 Pa·s at about 90-150° C., and may further have a viscosity in the range of about 15-50 Pa·s at about 110-150° C. Further, the applied polymer material may have a hardness in the range of about 40-60 shore D. These values provide the necessary reduction of stretchability of the knitted fabric but maintain the required elasticity of the knitted fabric.
The polymer material may be applied in layers with a thickness of about 0.2-1 mm. The polymer material may also be applied in several layers, e.g. on top of each other or in an overlapping fashion. Thus, the polymer material can be sprayed on and adjusted to the respective requirements on the overall thickness of the polymer material. In this regard, several layers, e.g. at least two layers, may have different thicknesses. There may be continuous transitions between areas of different thicknesses, in which the thickness of the polymer material continuously increases or decreases, respectively. In the same manner, two different polymer materials may be used in different areas in order to achieve desired properties.
The portion that is reinforced with the polymer material may be arranged in the toe area, the heel area, in the area of the tongue, on a lateral side in the midfoot area and/or on a medial side in the midfoot area of the shoe upper. Reducing stretching of the knitted fabric by a polymer material is particularly desirable in these areas. Further reinforced areas may be the area of the eyelets, the area of the sole or the ankles (if the shoes are sufficiently high).
According to certain embodiments, the first and/or the second portion of the knitted fabric comprises a first textile layer and a second textile layer, wherein the first textile layer comprises a yarn, and wherein the second textile layer comprises a monofilament. It is preferable for the portion coated with the polymer material to comprise the first textile layer and the second textile layer. It is also preferable for the second textile layer to be coated with the polymer material, i.e. the polymer material is arranged on the second textile layer. In other embodiments, it may be preferable that the portion comprising the first textile layer and the second textile layer is arranged in the area of the toes, the midfoot, the heel and/or the eyelets of the shoe upper.
In certain embodiments, the knitted textile furthermore comprises a fuse yarn comprising a thermoplastic material. The fuse yarn may be arranged (e.g. knitted into) in the first textile layer and/or the second textile layer. Furthermore, the fuse yarn may be arranged between the first textile layer and the second textile layer (e.g. placed between the layers). Upon applying pressure and temperature, the fuse yarn fuses with the knitted material and reinforces the knitted fabric. In doing so, the arrangement of the fuse yarn between the first textile layer and the second textile layer has the advantage that the mould does not get dirty during pressing. In certain embodiments, the material should not be in direct contact with the mould.
In certain embodiments, the first textile layer and the second textile layer are connected by weft-knitting or by warp-knitting. Thus, the monofilament, which is less elastic, can effectively reduce stretching of the more elastic yarn. This reduces stretching of the knitted fabric, wherein every single stitch is limited in stretching.
A further aspect of the invention is a shoe upper for a shoe, in particular a sports shoe with a least one portion comprising a weft-knitted fabric. The weft-knitted fabric comprises a first weft-knitted layer of a yarn and a second weft-knitted layer of a monofilament. The second weft-knitted layer and the first weft-knitted layer are connected such that the stretching of the first weft-knitted layer is reduced by the second weft-knitted layer.
The second weft-knitted layer may be only connected to the first weft-knitted layer. The second textile layer may be knitted into the first textile layer, i.e. the first and second textile layers may be interknitted. As a result, stretching of the first weft-knitted layer can be effectively reduced by the second weft-knitted layer, since the monofilaments of the second weft-knitted layer are not elastically deformable. While the second textile layer of a monofilament is indeed stretchable due to its stitches, it is considerably less than the first textile layer of yarn.
Preferably, the first textile layer comprises apertures for ventilation. Further, the second textile layer may comprise larger stitches than the first textile layer.
Further aspects of the invention include a method of manufacture of a shoe upper for a shoe, in particular a sports shoe, wherein the shoe upper comprises a first portion and a second portion that are jointly manufactured as knitted fabric. The method comprises a step of applying a polymer layer as a coating in only one of the two portions of the shoe upper.
The method may further comprise a step of pressing the polymer coated portion of the shoe upper under pressure and heat. The polymer melts due to pressure and heat and fuses with the yarn. Thus, the stiffness of the knitted fabric is increased and its stretching is decreased in the coated portion.
The polymer coating may be sprayed on, applied with a scraper or coating knife or by laying on. By means of such method steps the polymer material can be applied to the portion to be coated with particular ease.
In other embodiments, the knitted fabric comprises a first textile layer and a second textile layer, wherein the first textile layer comprises a yarn, and wherein the second textile layer comprises a monofilament. In this regard, the method further comprises the steps of applying the polymer material to the second textile layer and subjecting the shoe upper to pressure and heat, wherein the polymer material melts and penetrates the second textile layer, thus essentially coating the first textile layer. In the second step, the polymer material essentially connects to the fibers of the first textile layer, thus reinforcing the first textile layer. During this process, stitches are positioned relative to each other, either at their points of intersection or by the entire stitch being surrounded by the polymer and thus positioned or otherwise secured.
In further embodiments, an additional step of the method is compression-molding the coated textile material. By compression-molding the coated textile material the shoe upper can be provided with a certain shape in certain areas, e.g. a curved shape in the area of the heel or the toes. The shape of the shoe upper can either be adjusted to the last or to the foot itself.
In this regard, the yarn of the first textile layer and the monofilament of the second textile layer may comprise a higher melting point than the polymer material. Thus, it is possible that only the polymer material melts at suitable temperatures and fuses with the yarn of the first textile layer, without the yarn and the monofilament being destroyed or damaged.
In some embodiments, the yarn of the first textile layer comprises a fuse yarn, which comprises a thermoplastic material. Thus, the fuse yarn can fuse with the yarn and reinforce it when subjected to heat and pressure. Therein, it may be desirable for the monofilament and the yarn to comprise a higher melting point than the fuse yarn so that only the fuse yarn melts at suitably selected temperatures during pressing. In this regard, it may also be desirable that the monofilament and the yarn comprise a higher melting point than the thermoplastic material of the fuse yarn.
Further embodiments are described in further dependent patent claims.
In the following detailed description, embodiments of the invention are described referring to the following figures:
The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.
In the following, embodiments and variations of the present invention are described in more detail referring to a shoe upper for a shoe, in particular a sports shoe. However, the present invention can also be used otherwise, e.g. for clothing or accessories where supporting functions, stiffening, increased abrasion resistance, elimination of stretchability, increased comfort and precise fit to prescribed geometries are required.
The use of the weft-knitting technique enables a shoe upper to comprise areas with different characteristics, while it still can be manufactured in one single operation. The various characteristics or functions of the areas include stiffness, stability and comfort, for example. Various techniques are used in order to achieve such characteristics or functions, which will be described in the following. The described techniques include suitable knitting techniques (e.g. Jacquard, inlaid works and/or gusset technique), the selection of fibers and yarns, the coating of the textile material with a polymer, the use of monofilaments, the combination of monofilaments and polymer coating, the application of fuse yarns and multi-layer textile material. These and other techniques will be explained in the following, before embodiments of shoe uppers will be described that apply these techniques.
As shown in
Knitted fabrics constitute the majority of textile materials used for shoes. An essential advantage of knitted fabric over woven textiles is the variety of structures and surfaces that can be created with it. Using essentially the same manufacturing technique, it is possible to manufacture both very heavy and stiff materials and very soft, transparent and stretchable materials. The properties of the material can be influenced by the weft-knitting pattern, the yarn, and the needle size.
Weft-knitted textile materials are currently used for the manufacture of shoe uppers only to a limited extent, particularly for shoe lining. Textile materials of shoe uppers and the majority of shoe lining materials are mainly warp-knitted textile materials.
Weft-knitted textile materials 11, 12 are created by knitting with one thread from the left to the right. View 11 shows a front view and view 12 shows a back view of a weft-knitted material. In contrast, warp-knitted textile materials 13 are created by warp-knitting with many threads from the top to the bottom. The further classification of warp-knit goods and weft-knit goods is illustrated in
The manufacture of the final shape or outline is possible by flat knitting. To this end, a three-dimensional shape of the shoe upper has to be created by closing a seam. Creating a final outline is not possible in circular knitting. Here, it is necessary to cut out the final shape from the knitted material and to provide it with a seam along the edge.
Thus, the weft-knitting technique allows manufacturing of textile materials with different functional areas and simultaneously maintaining their outlines. As a result, it is possible to manufacture shoe uppers in one operation by means of the weft-knitting technique, as illustrated in
The structures of a weft-knitted material can be adjusted to functional requirements in certain areas, by weft-knitting patterns, the yarn or the needle size being selected accordingly. It is possible, for example, to include structures with large stitches or apertures within the weft-knitted textile material in areas where ventilation is desired. By contrast, in areas where support and stability are desired, fine-meshed weft-knitting patterns, stiffer yarns or even multi-layered weft-knitting structures can be used, which will be described in the following. The thickness of the weft-knitted textile material is equally variable.
Fibers are usually of a rather short length and are spun or twisted into threads or yarns. However, fibers can also be long and twirled into a yarn. Fibers may consist of natural or synthetic materials. Natural fibers include cotton, wool, alpaca, hemp, coconut fibers or silk. Among the synthetic fibers are polymer-based fibers such as nylon, polyester, Spandex or Kevlar, which can be produced as classic fibers or as high-performance or technical fibers.
The mechanical and physical properties of a fiber and the yarn manufactured therefrom are also determined by the fiber's cross-section, as illustrated in
A fiber having the circular cross-section 310 can either be solid or hollow. A solid fiber is the most frequent type; it allows easy bending and is soft to the touch. A fiber as a hollow circle with the same weight/length ratio as the solid fiber has a larger cross-section and is more resistant to bending, since deformations occur during bending. Examples of fibers with a circular cross-section are nylon, polyester, and Lyocell.
A fiber having the bone-shaped cross-section 330 has the property of wicking moisture. Examples of such fibers are acrylic or spandex. The concave areas in the middle of the fiber support moisture being passed on in the longitudinal direction, whereby moisture is rapidly wicked from a certain place and distributed.
The following further cross-sections are illustrated in
Individual fibers with their properties that are relevant for the manufacture of shoe uppers will be described in the following:
The following yarns can be applied for textile materials for shoe uppers:
Functional yarns are capable of transporting moisture and thus of absorbing sweat and moisture. They can be electrically conducting, self-cleaning, thermally regulating and insulating, flame resistant, and UV-absorbing, and may enable infrared remission. They may be suitable for sensors.
Stainless steel yarn contains fibers made of a blend of nylon or polyester and steel. Its properties include high abrasion resistance, higher cut resistance, high thermal abrasion, high thermal and electrical conductivity, higher tensile strength and high weight. Stainless steel yarn is only available in grey steel colors to date.
Electrically conducting yarns for the integration of electronic devices in textile materials.
Fuse yarns (see also section 5.7) are a mixture of a thermoplastic yarn and polyester or nylon. There are essentially three types of fuse yarn: a thermoplastic yarn surrounded by a non-thermoplastic yarn; a non-thermoplastic yarn surrounded by thermoplastic yarn; and pure fuse yarn of a thermoplastic material. After being heated to the melting temperature, the thermoplastic yarn fuses with the non-thermoplastic yarn (e.g. polyester or nylon), stiffening the textile material. The melting temperature of the thermoplastic yarn is defined accordingly.
A shrinking yarn is a dual-component yarn. The outer component is a shrinking material, which shrinks when a defined temperature is exceeded. The inner component is a non-shrinking yarn, such as polyester or nylon. Shrinking increases the stiffness of the textile material.
Further yarns for application in shoe uppers are luminescent or reflecting yarns.
Due to their structure with loops/stitches, weft-knitted or warp-knitted textile materials are considerably more flexible and stretchable than woven textile materials. For certain applications and requirements, e.g. in certain areas of a shoe upper, it is therefore necessary to reduce flexibility and stretchability in order to achieve sufficient stability.
For this purpose, a polymer coating may be applied to one side or both sides of knitted fabrics (weft-knit or warp-knit goods), but generally also to other textile materials. Such a polymer coating causes a reinforcement and/or stiffening of the textile material. In a shoe upper, it can serve the purpose of supporting and/or stiffening in the area of the toes, in the area of the heel, or in other areas, for example. Furthermore, the elasticity of the textile material and particularly the stretchability are reduced. Moreover, the polymer coating protects the textile material against abrasion. Furthermore, it is possible to give the textile material a three-dimensional shape by means of the polymer coating using compression-molding.
In a first step of polymer coating, the polymer material is applied to one side of the textile material. However, it can also be applied to both sides. The material can be applied by spraying on, coating with a scraper or coating knife, laying on, printing on, sintering, spreading, or by applying a polymer bead. An important method of applying is spraying on, which may be automatically performed. This can be carried out by a tool similar to a hot glue gun. Spraying on enables the polymer material to be evenly applied in thin layers. Moreover, spraying on is a fast method.
In various embodiments, the polymer spray on process may be automated. Preferably, the polymer material may be sprayed on in an automated process with a robot. The design of the polymer coating, e.g. its thickness and its two-dimensional or three-dimensional profile, may be controlled by suitably programming the robot. Thus, the spray on process may be carried out fast and reproducibly, and the design of the polymer coating can be flexibly varied as well as precisely controlled.
In further embodiments, the polymer material is applied by dipping the textile material in a polymer solution comprising polymer particles and water. The textile material may be completely dipped into the polymer solution, and the solution soaks through the textile material. Alternatively, only one surface of the textile material may be dipped or partly dipped into the solution at a time. In that case, the polymer solution may partially soak through the textile material, wherein the extent of soaking through may be controlled by the duration of the dipping process. In some embodiments, a further surface of the textile material, e.g. the opposite surface of the previously dipped-in surface, may be dipped or partly dipped into the same or into a different polymer solution having different properties such as different color pigments, different fibers, etc. Thus, the same or different polymer solution(s) may also partially soak through the textile material from further surfaces.
After the one or more dipping steps, excess polymer may be squeezed out of the textile material, e.g. with a roller, particularly in cases where the polymer solution was made to soak through the textile material. Subsequently, the textile material with soaked-in polymer is dried with heat.
In some embodiments, the polymer is applied by means of a “Foulard” technique: After dipping the textile material into a polymer solution and squeezing out excess polymer e.g. with a roller, as described above, the textile material is dried with heat such that the polymer infiltrates and/or coats the yarn of the textile material.
In other embodiments, the polymer is applied by means of a “thermosetting” technique: After the aforementioned dipping and squeezing out steps, the textile material is stretched out. Subsequently, a heat setting process is carried out.
In various embodiments, the polymer is applied in at least one layer with a thickness of about 0.2-1 mm. It can be applied in one or several layers, whereby the layers can be of different thicknesses. There can be continuous transitions from thinner areas to thicker areas between neighboring areas of different thicknesses. In the same manner, different polymer materials may be used in different areas, as will be described in the following.
During application, polymer material attaches itself to the points of contact or points of intersection, respectively, of the yarns of the textile material, on the one hand, and to the gaps between the yarns, on the other hand, forming a closed polymer surface on the textile material after the processing steps described in the following. However, in case of larger mesh openings or holes in the textile structure, this closed polymer surface may also be intermittent, e.g. so as to enable ventilation. This also depends on the thickness of the applied material: The thinner the polymer material is applied, the easier it is for the closed polymer surface to be intermittent. Moreover, the polymer material may also penetrate the yarn and soak it, thus contributing to its stiffening.
After application of the polymer material, the textile material is subjected to heat and pressure. The polymer material liquefies in this step and fuses with the yarn of the textile material.
In a further optional step, the textile material may be pressed into a three-dimensional shape in a machine for compression-molding. For example, the area of the heel or the area of the toes can be three-dimensionally shaped over a last. Alternatively, the textile material may also be directly fitted to a foot.
After pressing and molding, the reaction time until complete stiffening may be one to two days, depending on the type of polymer material used.
The following polymer materials may be used: polyester; polyester-urethane pre-polymer; acrylate; acetate; reactive polyolefins; co-polyester; polyamide; co-polyamide; reactive systems (mainly polyurethane systems reactive with H2O or O2); polyurethanes; thermoplastic polyurethanes; and polymeric dispersions.
Further, the polymer material may comprise fibers and/or pigments. Thus, the properties of the textile material may be changed. In certain embodiments, the fibers change at least one mechanical property, such as stability, stiffness, cut-resistance, etc. provided by a polymer coating applied to a textile material. In certain embodiments, carbon fibers are added to increase the stability provided by a polymer coating. Further, para-aramid fibers, e.g. Kevlar®, may be added for increased cut resistance. Additionally or alternatively, color pigments may be added to create a desired color appearance of a polymer coating irrespective of the specific polymer material used. The described addition of fibers or pigments does not affect the manufacturing process. Fiber-reinforced polymer material with and without pigments may be sprayed on or applied to the textile material in any of the further ways, as described above. In particular, fibers and pigments may be added to a polymer solution into which the textile material is dipped.
In certain embodiments, a non-woven polymer material e.g. a fleece is applied to the textile material. In these embodiments, the non-woven polymer material may be applied to that surface of the textile material that is to form the inner surface of an upper. Thus, the inner surface of an upper may be manufactured in an advantageous manner. In some embodiments, the non-woven polymer material is applied to the surface of the textile material, which forms the inner surface of an upper, and in addition may be applied to the surface of the textile material forming the outer surface of an upper. Therein, the non-woven polymer material may be applied in the heel and/or toe area. Thus, a convenient feel at the inner surface of an upper and a suitable stability in desired portions of the upper may be provided in a manufacturing step based on a single material.
In some embodiments, the non-woven polymer material is heat pressed or ironed to the respective surface or area of the textile material. According to certain embodiments, the polymer material used has a melting temperature of about 160° C.
The polymer material may comprise a viscosity of about 50-80 Pa·s at about 90-150° C., and may further comprise a viscosity of about 15-50 Pa·s at about 110-150° C.
The hardened polymer material may comprise a hardness of about 40-60 Shore D. Depending on the application, other ranges of hardness are also conceivable.
The described polymer coating is meaningful wherever support functions, stiffening, increased abrasion resistance, elimination of stretchability, increased comfort and/or fitting to prescribed three-dimensional geometries are desired. It is also conceivable to fit a shoe upper to the individual shape of the foot of the person wearing it, by polymer material being applied to the shoe upper and then adapting it to the shape of the foot under heat.
Monofilaments are yarns consisting of one single filament, that is, one single fiber. Therefore, the stretchability of monofilaments is considerably lower than that of yarns that are manufactured from many fibers. As a result also the stretchability of knitted fabrics manufactured from monofilaments is reduced. Monofilaments are typically made from polyamide. However, other materials, such as polyester or other thermoplastic materials, are also conceivable.
Thus, while a textile material made from a monofilament is considerably more rigid and less stretchable, this material does, however, not have the desired surface properties such as e.g. smoothness, colors, transport of moisture, outer appearance and variety of textile structures as usual textile materials have. This disadvantage is overcome by the material described in the following.
The monofilament may also be slightly melted in order to connect with the layer of yarn and to further limit any stretching. The monofilament then fuses with the points of connection with the yarn and fixes the yarn towards the layer made from the monofilament.
The weft-knitted material having two layers described in the preceding section may additionally be reinforced by a polymer coating as described in section 5.4. The polymer material is applied to the weft-knitted layer made from monofilaments. It does not connect to the polyamide material of the monofilaments, since the monofilament has a smooth and round surface, but essentially penetrates the underlying layer of yarn. During subsequent pressing, the polymer material therefore fuses with the yarn of the first layer and reinforces the first layer.
The polymer material has a lower melting point than the yarn of the first layer and the monofilament of the second layer, and the temperature during pressing is selected such that only the polymer material melts.
For reinforcement and for the reduction of stretching, the yarn of a knitted fabric may also be supplemented with thermoplastic material that fixes the knitted fabric after pressing. There are essentially three types of fuse yarn: a thermoplastic yarn surrounded by a non-thermoplastic yarn; a non-thermoplastic yarn surrounded by a thermoplastic yarn; and a pure fuse yarn of a thermoplastic material. In order to improve the bond between the thermoplastic material and the yarn, the yarn's surface is texturized. In certain embodiments, pressing takes place at a temperature ranging from about 110 to 150° C., and may further take place at a temperature of about 130° C. The thermoplastic material melts at least partially in the process and fuses with the yarn. After pressing, the knitted fabric is cooled so that the bond is hardened and stabilized.
In certain embodiments, the fuse yarn is knitted into the knitted fabric. In case of several layers, the fuse yarn may be knitted into one, several, or all layers of the knitted fabric.
In other embodiments, the fuse yarn may be arranged between two layers of a knitted fabric. In doing so, the fuse yarn may simply be placed between the layers. An arrangement between the layers has the advantage that the mold is not contaminated during pressing and molding, since there is no direct contact between the fuse yarn and the mold.
Various techniques will be described in the following, which may be relevant to the manufacture of a shoe upper made from knitted fabric (weft-knitted).
A textile material having more than one layer provides further possible constructions for the textile material, which provide many advantages. Several layers fundamentally increase solidness and stability of the textile material. In this regard, the resulting solidity depends on the extent to which, and the techniques by which, the layers are connected to each other. The same material or different materials may be used for the individual layers. A weft-knitted textile material having a weft-knitted layer made from yarn and a weft-knitted layer made from monofilament whose stitches are enmeshed was previously described in section 5.5. In particular, the stretchability of the weft-knitted layer is reduced due to the combination of different materials. It is an advantageous alternative of this construction to arrange a layer made from monofilament between two layers made from yarn in order to reduce stretchability and to increase solidity of the material. A comfortable surface made from yarn is obtained on both sides of the textile material in this way, in contrast to a harder surface made from a monofilament.
Multi-layered constructions also provide opportunities for color design, by different colors being used for different layers.
An alternative of multi-layered constructions are pockets, in which two textile layers are connected to each other only on one side so that a hollow space is created. It is then possible to introduce a foam material, for example, through an opening, e.g. at the tongue, the shoe upper, the heel or in other areas. Alternatively, the pocket may also be filled with a knitted fabric spacer.
A tongue may be manufactured as a continuous piece and connected with the shoe upper subsequently, or it can be manufactured in one piece with the shoe upper. Ridges on the inside may improve the flexibility of the tongue and ensure that a distance is created between the tongue and the foot, which ensures additional ventilation. Laces may be guided through one or several weft-knitted tunnels of the tongue. The tongue may also be reinforced with polymer in order to achieve stabilization of the tongue and e.g. prevent a very thin tongue from convolving. Moreover, the tongue can then also be fitted to the shape of the last or the foot.
Three-dimensional knitted fabrics may be used wherever additional cushioning or protection is desired, e.g. at the shoe upper or the tongue. Three-dimensional structures may also serve to create distances between neighboring textile layers or also between a textile layer and the foot, thus ensuring ventilation.
The knitted fabric is particularly stretchable in the direction of the stitches (longitudinal direction) due to its construction. This stretching may be reduced e.g. by a polymer coating, as described above in section 5.4. The stretching may also be reduced by various measures in the knitted fabric itself. One possibility is reducing the size of the mesh openings, that is, using a smaller needle size. This technique can be used at the shoe upper, for example. Moreover, the stretching of the knitted fabric can be reduced by knitted reinforcement, e.g. three-dimensional structures. Such structures may be arranged on the inside or the outside of a shoe upper. Furthermore, a non-stretchable yarn may be laid in a tunnel in order to limit stretching.
Colored areas with several colors may be created by using a different thread and/or by additional layers. In transitional areas, smaller mesh openings (smaller needle sizes) are used in order to achieve a fluent passage of colors. Further effects may be achieved by weft-knitted inserts (inlaid works) or Jacquard knitting.
The shoe upper 1 depicted in
In the area of the toes 610, reinforcement of the shoe upper is advantageous in order to protect the toes from impacts and to offer support to the foot in this exposed area. Moreover, three-dimensional molding may be desirable in this area.
Reinforcement of the textile material may essentially be achieved in four ways. Firstly, a smaller needle diameter may be used, resulting in greater density of stitches and thus greater solidity of the weft-knitted material. Secondly, the area of the toes 610 may be weft-knitted in a multi-layered manner, as described above in section 5.8.
Thirdly, a fuse yarn may be used in one or several layers, as described above in section 5.7. In doing so, a layer may either be entirely weft-knitted from fuse yarn or merely include a fuse yarn. Fourthly, the area 610 may be reinforced by a polymer coating, as described above in section 5.4. By subsequent melting under pressure and heat and the ensuing cooling and hardening, the area of the toes is given substantially greater solidness. Finally, this area can be given a three-dimensional shape by pressure-molding (see section 5.4).
Combining two or more of the aforementioned techniques results in particularly effective reinforcement.
The base area 620 spans large parts of the shoe upper 1. Considerably greater air-permeability is desirable in this area than in the area of the toes 610 and in the area of the heel 650, in order to enable good ventilation of a shoe having the shoe upper 1. In order to solve this problem, a smaller stitch diameter may be used, on the one hand, which gives the weft-knitted material made from yarn great solidness.
On the other hand, apertures are provided for in the weft-knitting pattern, which enable airflow. However, these apertures increase the stretchability of the weft-knitted material. In order to make the resulting weft-knitted material more solid and less stretchable, a second layer made from monofilament is therefore knitted in or connected with the first layer in another manner on the inside of the base area 620. Since the monofilament has a low stretchability, the stretchability of the first layer is also decreased.
In order to prevent a significant restriction of air-permeability of the first layer made from yarn, the size of the stitches for the monofilament of the second layer may be larger than that for the yarn on the first layer and/or the thread thickness of the monofilament may be significantly smaller than that of the yarn of the first layer. This can also be seen in
In some embodiments, the diameter of the apertures is approximately 1-2 mm and there are approximately 8-12 apertures per cm2. Due to these dimensions, a certain ventilation of the shoe is enabled, on the one hand, and, on the other hand, the two-layered material of the area 620 is of sufficient solidity to support the foot during movement against the occurring forces.
In certain embodiments, a texturized knitting polyester yarn with a yarn thickness of about 660-840 dtx, comprising four to five individual threads, with each individual thread having a yarn thickness of about 160-170 dtx, is used for the base area 620. The unit dtx refers to a yarn with a yarn thickness of about 1 g/10,000 m. According to some embodiments, the base area is weft-knitted with a fine structure of about 12-14 stitches per inch.
The areas 630 are optional and have greater air-permeability than the surrounding areas, e.g. the area 620, due to a wider diameter of the apertures in the pattern of the material and/or a greater density of these apertures.
The areas 640 are arranged on the medial and lateral side of the shoe upper and are manufactured with a suitable pattern of the material in order to ensure support of the foot in these areas. The areas 640 have a smaller diameter of the apertures in the pattern of the material and/or a smaller density of these apertures than the base area 620, in order to achieve greater solidness. In order to reduce stretching, the areas 640 may also be coated with a polymer material, as described in section 5.4.
The area of the heel 650 may also be reinforced by a multi-layered textile material. Furthermore, the area of the heel 650 may be provided with a further layer of monofilament, as described in section 5.5, in order to reduce the stretchability of that area.
Considerable reinforcement of the area of the heel 650 as well as the area of the toes 610 is achieved by using fuse yarn, as described above in section 5.7. Moreover, the area of the heel 650, just as the area of the toes 610, may be coated with a polymer material to reinforce the weft-knitted textile material, as described above in section 5.4. The use of fuse yarn results in stiffer material than a polymer coating, since fuse yarn is capable of forming a thicker layer. On the other hand, using polymer is cheaper than using fuse yarn. Therefore, it may also be possible to apply a polymer coating in different thicknesses, e.g. thicker in the area of the heel 650 and/or the area of the toes 610 than in the medial/lateral areas 640.
The area 660 runs along the area of the shoe's opening and the lacing and is additionally reinforced, e.g. by a multi-layered textile material, which may also comprise a monofilament. In order to further reinforce the material, the area 660 is reinforced with a polymer material, which may have a greater thickness than in the areas 640, e.g. by coating with several layers. Apertures for the laces may be melted through.
The so-called gusset technique, which is depicted in
The area 670 at the upper back end of the shoe upper 1 may e.g. be formed as a pocket by a double-layered material, which is open on one end in order to place a foam material therein for wear comfort and in order to protect the foot. Alternatively, a knitted fabric spacer may provide the desired cushioning. The area 670 is weft-knitted in one piece with the rest of the shoe upper 1. It comprises two layers made from yarn (no monofilament), whereas these two layers are not enmeshed. They are connected on one side such that a pocket is formed.
The structures 680 are embossed by suitable weft-knitting patterns and structures and may be of different colors, respectively. Moreover, a uniform weft-knitting pattern may span the respective strips. A different weft-knitting technique is applied in the area of structures 680, so as to enable a transition of colors. The structures 680 may additionally also be arranged symmetrically in the second one of the areas 640.
The manufacture of a shoe upper by knitting can be fully automated on knitting machines, as they are for example provided by the company Stoll. A knitting program is programmed for that purpose, and subsequently the process runs automatically, virtually without further effort. The manufacture of a shoe can be rapidly re-programmed without great effort, i.e. it is possible to change areas, to adjust the size, to exchange yarns and alter patterns of the material without having to change the machine itself.
Thus, the design of the shoe (color, shape, size, fit, function) can be rapidly modified. This is advantageous for production in a factory, as well as for production at a point of sale. Thus, a customer might specify his or her data in a shop and the shoe would subsequently be knitted according to his or her individual dimensions. The shoe can be adjusted to the person wearing it by the shoe upper being adjusted to the shape of the foot of the person wearing the shoe.
To this end, it is possible to adjust areas coated with polymer material (see section 5.4) as well as areas with fuse yarn (see section 5.7) to a last or a foot.
The following examples are described to facilitate a deeper understanding of the invention:
Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and sub-combinations are useful and may be employed without reference to other features and sub-combinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications may be made without departing from the scope of the claims below.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102012206062.6 | Apr 2012 | DE | national |
| 13161357.2 | Mar 2013 | EP | regional |
This application is a continuation of U.S. patent application Ser. No. 13/861,896, field on Apr. 12, 2013, entitled SHOE UPPER (“the '896 application”), which is related to and claims priority benefits from German Patent Application No. DE 10 2012 206062.6, filed on Apr. 13, 2012, entitled SHOE UPPER (“the '062 application”), and European Patent Application No. 13161357.2, filed on Mar. 27, 2013, entitled SHOE UPPER (“the '357 application”). The '896, '062 and '357 applications are hereby incorporated herein in their entireties by this reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13861896 | Apr 2013 | US |
| Child | 16130995 | US |
