WO2022136031A1

WO2022136031A1 - Shoe

Info

Publication number: WO2022136031A1
Application number: PCT/EP2021/085762
Authority: WO
Inventors: Cornelius Schmitt; Peter Graeff
Original assignee: Zellerfeld R&D GmbH
Priority date: 2020-12-23
Filing date: 2021-12-14
Publication date: 2022-06-30
Also published as: DE102020134848A1

Abstract

The invention relates to a shoe consisting of at least one upper and at least one sole, the upper and the sole being made as a single piece from at least one thermoplastic material in a 3D printing process. The upper and the sole have different structures.

Description

shoe

The invention relates to a shoe consisting of at least one upper and at least one sole, the upper and sole being produced in one piece from at least one thermoplastic material by 3D printing.

A shoe generally includes an upper and an associated sole. The sole typically includes an insole, a midsole, and an outsole. The midsole is usually used for cushioning, while the outsole is essentially an abrasion-resistant layer. In general, the soles are designed in a way to provide high stability on the one hand and to absorb an impact load when the foot hits the ground on the other hand. The sole often consists of so-called ethylene vinyl acetate foam (short: EVA foam), which can have different degrees of hardness.

The upper is essential to the fit, comfort and level of support of the foot. Different parts of the foot need different levels of support or cushioning. For maximum comfort, the properties of an upper must be locally adjusted to properly support and cushion the wearer's foot. However, this poses a manufacturing challenge because manufacturing an upper with multiple different functional areas is complex. In particular, when using traditional manufacturing techniques such as weaving, individual sheets of material with different properties, e.g. in relation to elasticity, must be used for different parts of the upper. The upper part is often made of a mesh fabric, particularly in the case of sports and leisure shoes. "Mesh" stands for a linked structure of fibers. It is therefore a kind of lattice, which is created from interconnected threads. The yarn is either knitted or woven to create the holes characteristic of mesh fabric. The fabric can be made from a variety of materials - In known shoes, the upper part is glued to the sole. This leads to some disadvantages. For example, the durability of the connection between the upper and sole is not guaranteed. The effect of the adhesive used can decrease due to aging processes, so that the upper part detaches from the sole. The load-bearing capacity of the glued connection is also limited.

It has also been known for a number of years to produce shoes using the so-called 3D printing process. In 3D printing, three-dimensional parts are usually built up in layers from one or more materials. For example, plastics, resins, ceramics and/or metals are used as materials.

In this context, for example, the rapid prototyping method or stereolithography method (SLA for short) is known. The workpiece is in a liquid bath made of photopolymer. This is a polymer that changes its properties when exposed to light in the UV-VIS region of the electromagnetic spectrum. In this process, the workpiece is gradually lowered deeper into the liquid bath. A laser scans the base fabric at each step to create the desired shape. With the SLA process it is possible to create filigree structures and smooth surfaces. With this method, however, it is hardly possible to create cavities in the workpiece to be manufactured. Also, with this method, different structures cannot be printed in one piece in one printing process.

Another 3D printing process is selective laser sintering (SLS for short). In this process, plastic powder is melted using heat and a laser. The laser beam fuses the individual particles hit. The workpiece is then lowered by one layer and refilled with powder. This process is repeated until the complete object is printed. With this method, no supporting elements have to be manufactured, even with complicated geometries. However, it is also not possible with this method to produce closed cavities. Also, different materials cannot be processed together. Another 3D printing process is known as the so-called fused deposition modeling (FDM) or fused filament fabrication (FFF). a molten material. Thermoplastics are usually used here. For the layered production of the respective component, printing material is applied to a printing plate via at least one printer nozzle of a 3D printing device, e.g. in the form of a so-called 3D printer The printing material emerging from the printing nozzle is built up layer by layer by a sequence of traversing paths within a plane, with the aid of a computer, to build up the respective three-dimensional component.

Various 3D printing devices are known from practice, which are provided in particular for the layered application of printing material for the production of three-dimensional components and which can be operated with different plastics. In practice, depending on the component to be produced, the printing material to be used is often varied as a test until a prototype of the component to be printed with the required material and component properties is available.

In the case of shoes that are manufactured using the 3D printing process, the upper and sole are usually printed separately from one another because, as explained above, different requirements are placed on the upper than on the sole. The upper part is then glued to the sole in a known manner, which entails the disadvantages mentioned above. However, shoes are also known that are produced entirely using the 3D printing process, in which case both the sole and the upper part are printed in one operation. This eliminates the disadvantages caused by gluing the sole to the upper. However, these shoes are uniform in their structure. As a result, the sole has the same properties as the upper, although both parts should meet completely different requirements. The shoes made in this way are therefore in principle only suitable for use as slippers or bathing shoes; they are unsuitable for use in particular as sports shoes.

Against this background, the invention is based on the object of creating a shoe that is produced using the 3D printing process and at the same time meets the different requirements for the upper and sole. According to the invention, this object is achieved with the features of claim 1.

With the invention, a shoe is created that is manufactured using the 3D printing process and at the same time meets the different requirements for the upper and sole.

In the case of shoes that are known and printed in the conventional way, no long-lasting connections between the structures are created from different printing processes, for example for the production of the upper material on the one hand and for the production of the sole on the other hand. Rather, the materials simply abut one another and are then connected to one another using known joining methods. Advantageously, to eliminate this disadvantage, the structure of the upper and the structure of the sole mesh at their contact points. This creates a stable and long-lasting connection between the various structures.

At least one structure is advantageously surrounded by an outer shell. The attachment of an outer shell offers the possibility of changing the properties of the respective structure or closing the structure. For example, by attaching the outer shell in the area of the structures forming the sole, there is the possibility of protecting them against the ingress of water. In this way, even with an open-pored structure, water or dirt can be prevented from being deposited in the structure.

Other developments and refinements of the invention are specified in the remaining dependent claims. Exemplary embodiments of the invention are shown in the drawings and are described in detail below. Show it: FIG. 1 shows the section in the area of entry through a 3D-printed shoe according to the prior art;

FIG. 2 shows the section in the area of entry through a shoe produced by 3D printing according to the invention;

FIG. 3 shows the section in the area of entry through a shoe produced by 3D printing according to the invention in a different embodiment;

FIG. 4 shows the schematic representation of two interlocking structures;

FIG. 5 shows the section in the area of entry through a shoe produced by 3D printing according to the invention in a further embodiment;

FIG. 6 shows the section in the area of entry through a shoe produced by 3D printing according to the invention in an additional embodiment;

FIG. 7 shows the section through the sole in the area of entry through a shoe according to the invention produced by 3D printing;

FIG. 8 shows the section in the area of the metatarsus through a 3D-printed shoe according to the invention in a modified embodiment;

FIG. 9 shows an exemplary selection of structures in the form of six different geometries.

The shoe according to the present invention comprises an upper, also called an upper, and a sole, also called a bottom. In the context of the present invention, upper means the area of the shoe that surrounds the foot from the side facing away from the ground—that is, from above. Sole in the context of the present invention means the area of the shoe on which the foot essentially rests and which, when used as intended, is in contact with its underside with the ground. The sole can have a multi-layer structure and can include an insole, a midsole and an outsole, among other things. The sole can also enclose the foot at least in sections, as is shown in FIGS. 3 and 6, among other things. The enclosing in sections can be both along the longitudinal sides of the foot as well as in the area of the toes and heel.

The upper and sole are made in one piece using 3D printing. As a result, the upper and the sole are produced in a continuous printing process, using the “Fused Deposition Modeling” (so-called FDM printing) or the “Fused Filament Fabrication” (so-called FFF printing) process. A thermoplastic material in the form of rolls or rods is melted in the extruder. It is also possible to feed the thermoplastic in the form of granules to the extruder or to the liquid melt. The molten plastic is forced out of one or more nozzles and transferred to a print bed. There, the 3D printer shapes the liquid material layer by layer according to the structure defined in the 3D files by following predetermined paths, resulting in the desired shape. The plastic used in this procedure can be a thermoplastic elastomer (TPE), a thermoplastic polyurethane (TPU), a polyamide (PA), for example Nylon®, or polyethylene terephthalate (PET).

The sections through the 3D printed shoes shown in the figures show designs that are produced using vertical printing. In this case, vertical means that when the shoe is pressed, the shoe is built up from the heel cap, which surrounds the heel when the shoe is worn, towards the front cap, which surrounds the toes, or vice versa. However, the invention is not limited to this type of printing. Rather, there is also the possibility of printing the shoe horizontally, in which the shoe is built up starting with the sole.

According to the invention, both the upper part and the sole have different structures. Structures mean discrete partial areas within the entire shoe that can be distinguished from one another in terms of their pressure parameters and properties. The differences can exist in the material, the density of the print, the geometry, but also in the color used. The shoe can be made up of any number of different structures exist. Examples of different geometries are shown in FIG.

In the schematic illustration according to FIG. 1, a shoe produced by 3D printing according to the prior art is shown. This shoe is recognizable as being made in one piece. It has only a single structure within the meaning of the present invention. Consequently, the properties are the same in all areas of the shoe, which is why there are no special properties in the area of the sole or in the area of the upper. The shoe can therefore have special cushioning properties which are conducive to comfort when walking or running; but such properties are only of secondary importance for the upper part. Rather, good breathability is desirable in this area, for example. The shoe known from the prior art cannot guarantee this.

The shoe according to the invention is different. The use and arrangement of different structures on the shoe according to the invention in relation to the shoe known from the prior art can be explained on the basis of the exemplary schematic representation according to FIG. The shoe has three different structures 1 , 2 , 3 as can be seen. On its shaft edge, which surrounds the entry, it has a first structure 1, which is followed by structure 2, which in this schematic exemplary embodiment forms the material of the upper part of the shoe. The structure 3 connects to the structure 2, which forms the sole of the shoe. The different hatching of the structures is intended to clarify the different properties of the three structures.

The structures 1, 2, 3 can differ in particular in terms of their density and their material. For example, the structure 3 can have very good damping properties in order to achieve a high level of comfort when stepping on the ground. The structure 2, on the other hand, can be particularly kind to the skin, so that there are no negative influences in the event of direct skin contact. In addition, the structure 2 can be designed to be particularly breathable. Last but not least, the structure 1 can form a kind of padding to avoid pressure points To avoid the entry or shaft edge area, on the other hand, the structure 1 can have a higher density than the structure 2 of the upper part in order to provide the required support and protection against tearing.

In a modification of the embodiment according to FIG. 2, in the exemplary embodiment according to FIG. 3, the structure 1 is pressed as a reinforcement into the structure 2 of the upper part in the area of the upper edge. This achieves a uniform structure in the area in contact with the foot and on the outside of the upper. The imprinted structure 1 is used for reinforcement to protect against tearing, but in contrast to the exemplary embodiment according to FIG. 2, it is not visible from the outside.

The shoe according to the invention is also characterized by a particularly good connection between the different structures. This is achieved in that the various structures interlock at their contact points, as can be seen from FIG. 4 and is illustrated by way of example in structure 2 of the upper and structure 3 of the sole. The various mutually adjacent structures overlap at their connection or contact points. This is achieved by printing the structures "into each other" per layer. In the transition area of the structures, they connect by weaving them together. This is possible to mix different materials (e.g. hard material for the heel and soft upper material (Flexible and mesh) to connect, as well as to connect different colored material securely.

In the exemplary embodiment according to FIG. 5, the shoe also consists of the structures 2 and 3 for the upper part and the sole. In this exemplary embodiment, it can be seen that the entire area adjacent to the foot is printed in the same structure 2 . Consequently, the area of the insole is also formed by the structure 2 and--not shown in the drawing--engages with the structure 3 of the sole in order to achieve the good connection described above. Due to the complete enclosure, the foot comes in contact with the same structure in the entire area in contact with the foot, resulting in a comfortable fit. The different characteristics that exist with normal shoes This avoids embossing and properties in individual areas, eg injected soles and textile or leather uppers. At the same time, the edges present in the usual shoe construction, where the different structures meet, are avoided.

In the exemplary embodiment according to FIG. 6, the area of the insole is also formed by the structure 2 . In addition, the shoe in this embodiment has different structures 3, 4 in the area of the sole; the structure in the sole varies accordingly. This counteracts the following problem: Structure 2 of the upper is usually softer than structure 3 of the sole. However, modern shoes, in particular for sport and leisure, have soles which exceed the height of the area where the foot strikes. Consequently, the sole protrudes beyond the area of the insole of the shoe, particularly on the long sides of the shoe, as can be seen in FIG. 6, among other things. Up to now, such a configuration has led to severe restrictions in the movement of the foot due to the firmer structure of the sole. To eliminate this disadvantage, in the exemplary embodiment according to FIG. 6, the sole in the area above the area where the foot steps on is formed by the less dense and therefore softer structure 4. As a result, the foot has freedom of movement that is not restricted by the sole, although the design of the sole protrudes beyond the area where the foot strikes. Of course, there is also the possibility, if required, of making the structure 4 denser than the structure 3, for example if increased stability is desired in this area of the shoe in order to give the foot more support.

In the exemplary embodiments according to FIGS. 7 and 8, the structure of the sole is made from two materials in each case. This makes it possible to influence the properties of the shoe. In the exemplary embodiment according to FIG. 7, a joint reinforcement in the form of a structure 5 is pressed into the sole. The joint reinforcement prevents the foot, especially the longitudinal arch of the foot, from sinking in the shoe and losing support. For this reason, it is often desirable to build such joint reinforcements ("shanks") into the shoe. This is usually done in classic shoe manufacturing by integrating metal strips that are usually used in the midsole. Through the inventive direct compression If the hard material is pushed into the soft sole of the fully printed shoe, which consists of several structures, the joint reinforcement can be easily integrated. In its simplest form, the joint reinforcement can have the shape of a small plate. In addition, by printing the joint reinforcement, the strength and stiffness of the material can be adjusted, and the weight can be distributed over a larger area. In addition, the joint reinforcement can be adapted to the shape of the foot, which also increases the wearing comfort.

In the exemplary embodiment according to FIG. 8, the outsole is printed on its side facing the ground with a structure 6 made of a denser structure than the remaining part of the sole; optionally, it can also be a harder material. The sole is thus better protected against abrasion. The outsole is therefore much more durable. As a modification of the exemplary embodiments, there is also the possibility of realizing the structures 5 and 6 by using a significantly denser print instead of other materials. Conversely, this also applies to the effect that the structures 1 to 4 each consist of different materials in order to achieve comparable results.

In FIGS. 2, 3 and 5 to 8 the structures are partially surrounded by an outer shell 7 . A selected area of the structures forming the shoe can be closed with the outer shell 7 . The outer shell 7 can also be multi-layered, as is the case, for example, in the area of the structures 3 and 4 forming the sole in the exemplary embodiment according to FIG. The outer shell 7 can vary in thickness depending on the application. It can also only partially surround the respective structure. As can be seen, the outer shell 7 can also surround a structure in the inner region of the shoe, as is shown, for example, in FIGS. 3 and 4 in the structure 3 forming the sole. In contrast to what is shown in the figures of the exemplary embodiments, the structure 2 can also be surrounded by an outer shell. As a rule, this will only rarely be the case, since this restricts air permeability, which is undesirable in large parts of the structures forming the upper.

Claims

patent claims

1 . Shoe consisting of at least one upper and at least one sole, the upper and sole being produced in one piece by 3D printing from at least one thermoplastic material, characterized in that the upper and the sole have different structures (1 to 6).

2. Shoe according to claim 1, characterized in that the structure of the upper part and the structure of the sole mesh at their contact points.

3. Shoe according to claim 1 or 2, characterized in that the density of the structure of the upper and/or the sole varies.

4. Shoe according to one of the preceding claims, characterized in that the structure of the upper part and/or the sole is made of at least two materials.

5. Shoe according to one of the preceding claims, characterized in that an inner side is provided which is formed by a further structure which engages in one another at their contact points with the structure of the upper and the sole.

6. Shoe according to one of the preceding claims, characterized in that the structure of the upper part is printed in the region of the upper edge as a structure which has a higher density than the density of the upper part.

7. Shoe according to one of the preceding claims, characterized in that a reinforcement is pressed into the structure of the upper part in the area of the shaft edge.

8. Shoe according to one of the preceding claims, characterized in that at least one structure is surrounded by an outer shell (7).