EP1952716B1 - Flexible insole for increasing the weight of shoes - Google Patents

Abstract

The flexible shoe-insert (1) is extended over a partial area of a foot sole and is injection-molded in which the shoe is inserted and is again detachable. The shoe insert is made from a material mixture with thermoplastic material and metallic particles and has a foot-bed-like or a flat form. The thermoplastic material is ethylene-vinyl acetate or thermoplastic polyurethane.

Description

The invention relates to a flexible shoe insert for increasing the weight of shoes, which causes an increased calorie requirement in a wearer of such shoes.

The increase in weight of shoes to increase calorie consumption or to achieve an increase in performance during exercise is already known from various publications.

DE 601 01 444 T2 describes a weight embedded in the outsole of a shoe for increasing the weight of the shoe. In this case, the outsole of a shoe according to this document has an upwardly to the sole of the foot facing recess into which a weight, which is manufactured separately embedded. The weight consists of a mixture of an elastic material and metallic grains, wherein the mixture is poured in the liquid state of the elastic material in a container, and the container is embedded together with the mixture as a single weight in the recess of the outsole.

A disadvantage of the prior art here is that the outsole with the recess and the embedded in the outsole weight must be made separately. The two parts are joined together in a next step to a heavy shoe outsole. The shoe is then completed with the heavy sole. This is a complex process and causes correspondingly high costs.

Another disadvantage of the prior art is the fact that the embedded in the outsole weight is not removable from this. At least not without placing a replacement body in the recess of the outsole.

US 2004/0250450 A1 discloses a shoe insert for increasing the weight of shoes which extends at least over the area of a sole of the foot and which causes increased demand for calories in a wearer of such shoes. The shoe insert can be inserted into and removed from the shoe. It consists of a material combination of a thermoplastic material and metal particles and also has a footbed-like shape.

The shoe insert consists of a carrier and a cover layer, which is firmly connected to the carrier. The carrier, which is preferably made from polyphenylene sulfide (PPS), can take up lead and thus weigh more than one pound. The PPS and lead combination can be formed by injection molding.

US 5,758,435 shows a sports shoe with a regular array of weight chambers in a flexible outsole that can be filled with weights. The weights are first formed from a mixture of metal particles and a binder and then placed in the weight chambers. The binder is a material that hardens by drying.

US 3,109,245 describes a shoe with a heavy insole, which is incorporated in the shoe. The insole is a layered body having a base layer and a topsheet. The base layer consists of a material mixture of butadiene-styrene copolymer (GR-S) mixed with lead oxide. The material mixture is cured in a mold giving shape to the base layer at a temperature of 325 ° C for about 20 minutes.

WO 02/45534 A1 shows a sports shoe insert which can absorb weighting metal parts and is designed so that it can be inserted into a training shoe. The complaining Metal parts are thus fixed in a certain position within the training shoe. In a specific embodiment, in a flexible, porous, soft or elastic material, which is in liquid form, as a powder or granules, weighted material is introduced by mixing, wherein the weighting material may have substantially any size and shape. The material mixture of the liquid material and the particles is then cured in a mold to form an insert for a training shoe.

WO 2005/110139 A1 describes a training shoe with a lower sole connected to the upper of the shoe, which has receptacles that are open to the top (to the shoe interior). Weights can be introduced in these recordings. An insole is removably disposed on the upper surface of the weights and thus covers the weights. The weights are prepared from a molding compound and weight additives added to the molding compound. The molding compound may be a rubber or a plastic. As weight additives are proposed magnetic powder, stone powder or metal powder. The weights are formed as moldings and can be removably introduced into the receptacles of the lower sole.

If the metal particles, as in conventionally produced shoes whose weight is increased, introduced by introducing into the liquid state of the elastic material, it is not guaranteed in this type of mixture that each individual metal grains is surrounded by the elastic material. When mixing elastic material and metal granules or particles by (pressure-free) casting into a mold, partial segregation of the constituents due to gravity occurs, with the metal particles settling on a lower surface.

As a result, there is a risk that cracks may occur in a deformation of the sole in a deformation of these weights thus produced on the side on which a higher concentration of the metal particles is present.

Furthermore, by such a separation of the two components, the desired weight distribution of the weights thus produced for shoes is not guaranteed, which may result in wearing such equipped with such a weight shoes that certain muscle groups are overstressed.

Further, the incorporation of metal particles in the liquid state of the elastic material is limited to about 50% by weight. An amount greater than 50% by weight of metal granules in the weight which complains the shoe leads to increased brittleness of the weight, whereby the elastic properties are no longer sufficient and cracks can occur in the weight or fragments or individual metal particles can fall out of the weight during deformation. These fragments can then get into the interior of the shoe and can cause an uncomfortable or even painful wear on the wearer of the shoe.

The object of the invention is to provide a shoe insert which increases the weight of a shoe and avoids the disadvantages of the prior art.

According to the present invention there is provided a shoe insert which increases the weight of a shoe so as to increase the caloric demand of a wearer of such a shoe. The shoe insert according to the present invention is injection molded using a material mixture consisting of at least a thermoplastic material and metal particles. Compared to pouring, pouring or pouring the material mixture into a container according to DE 601 01 444 is ensured by the injection molding of the material mixture that all metal particles are at least so far surrounded by thermoplastic material that an elastic or flexible deformation of the shoe insert without the formation of cracks is possible.

The shoe inserts produced according to the invention have a desired distribution of the thermoplastic material and the metal particles such that not only each individual metal particle is surrounded by the thermoplastic, but that the outer sides of the injection molded shoe insert have a virtually closed surface of thermoplastic material. In this case, a practically closed surface means that the thermoplastic material is more visible on the surface than the metal particles. This also means that in a shoe insert according to the invention, the concentration of metal particles in its interior is higher than at the respective outer surfaces. The arranged inside the shoe insert metal particles are therefore individually so surrounded with the thermoplastic material that a high flexibility of the shoe insert part is given. This ensures that no crack formation occurs during any type of deformation of the shoe insert according to the invention and no metal particles or other particles can fall from the shoe insert into the interior of the shoe.

Due to the good enclosing of the metal particles, the proportion by weight of metal particles can be greatly increased with the injection molding process, and proportions by weight of 90% by weight and more can thereby be achieved. This is compared to the conventionally produced weights for increasing the weight of shoes or other conventionally made, heavy shoes a significantly higher weight gain for shoes achievable. The effect to be achieved by the weight increase, ie an increased calorie consumption and / or increase in the Performance or the training effect can be achieved much better with the shoe inserts according to the invention.

To increase the wearing comfort shoe insert according to the invention can be provided on its upper side with a soft, flexible, skin-friendly upper layer, which comes into contact with the sole of the foot.

Advantageously, the upper side opposite the underside of the shoe insert part is provided with a layer which, for example, consists of the same material as the upper layer. But it can also have a different material to advantageously prevent slippage of the shoe insert in the shoe. Other coatings, in particular heat-insulating coatings or damping coatings, likewise fall within the scope of the present invention.

Particularly advantageously, both the material for the upper layer and, if desired, the material for the lower layer before injection molding is introduced into the injection mold, and the injection of the material mixture takes place between the two materials. A further advantageous variant consists in that the upper layer and the lower layer consist of the same material and the same surface material preferably completely surrounds the shoe insertion part after the injection molding.

When the shoe insert is provided with a backsheet and a topsheet, the two layers are joined together at the peripheral edge of the shoe insert such that particles that could dissolve out of the injection molded mix are retained by the surrounding top and backsheet sheath.

However, due to the injection molding process for making a weight-increasing shoe insert, it is not necessary to place protective layers around the molded article. By injection molding, the metal particles are surrounded by the thermoplastic material so that no dissolution of particles occurs during normal use of the shoe insert. Therefore, the shoe insert according to the invention without upper layer and / or without lower layer be used in a shoe, without it comes to the wearer of the shoe to an uncomfortable wearing feeling. To increase the wearing comfort of the shoe insert, however, it is advantageous to provide at least one upper layer. An underlayer is not required for the aforementioned reasons, but may nevertheless be provided if it is to fulfill a specific function.

Further advantageously, the shoe insert according to the invention is injection-molded in such a way that, for example, a top layer of a shoe sole, which comes into contact with the sole of the foot, is molded directly onto the flexible weight-increasing material mixture. That is, to the flexible shoe insert, here z. As an insole, to increase the weight of a shoe, a soft skin-friendly, comfort-enhancing and / or visually appealing upper layer is formed in the same step in which the material mixture of a thermoplastic and metal particles is injected into a corresponding injection mold. The material for the upper layer is already inserted before injection into the injection mold. A subsequent application of a layer is then no longer necessary, but injecting such a top layer is not absolutely necessary. Such a topsheet may also be applied to the shoe shoe weight increasing shoe by any other suitable method of connection. It should also include a complete wrapping of the weight-increasing shoe insert with a top layer of the invention.

As described above, the backsheet can be molded to the shoe insert according to the present invention in the same manner. In this case, upper and lower layers can be attached to the same time directly in the manufacture of the shoe insert according to the invention.

The shoe insert according to the invention is shaped so that it can be inserted into a shoe and removed from this shoe again. The shoe is usable with or without the shoe insert in its normal function.

The shoe insert according to the invention is suitable for all types of shoes, such as. As professionally used shoes, sports shoes, casual shoes, as well as street shoes or boots of all kinds. The shoe insert according to the invention but can also be used in sports shoes, where it does not depend on the flexibility of the sole so much, such as skiing, roller blading or skating.

The shoe insert according to the invention, for example in the form of an insole, is distinguished not only by its increased weight compared to a conventional, purely thermoplastic insole, but also in that the flexibility of the insole corresponds approximately to the flexibility of the insole, which is made only of thermoplastic material has been.

As already mentioned above, the shoe insert according to the invention is produced by injection molding with a material mixture comprising at least one thermoplastic and metal particles. For this purpose, the mixture of the thermoplastic material and the metal particles is prepared and processed in such a way that after injection molding the shoe insert is deformable elastically and without cracking. This means that crack formation is ruled out, which means that elastic deformation, albeit only in some areas, would no longer be possible. This should u. a. It can also be avoided that a shoe insert becomes brittle and fragments occur inside a shoe, which leads to a strong reduction in wearing comfort.

As thermoplastic materials, all injection-moldable plastics can be used, which are elastically deformable after injection molding.

The metal particles used can be present in a wide variety of varieties and shapes. These forms include z. As the powder form, spherical shape, cylindrical shape, rectangular shape, flake shape or the like.

As already indicated above, the mixture of materials must be processed. For example, an adaptation of the materials in quantity, size, shape and / or color takes place. An admixture of other materials is included.

If the materials which are to be used to produce a flexible shoe insert according to the invention are matched and mixed, they can be injected into an injection mold by applying a temperature, which is above the melting point of the thermoplastic material and injected high pressure into an injection mold. Advantageously, a material which forms the upper layer of the injection-molded shoe insert according to the invention is already located in the injection mold. The flexible shoe insert can be molded in a variety of forms. In this case, forms are also included which can fulfill an orthopedic function. But also aesthetic or functional properties and shapes can be taken over by the injection-molded shoe insert. Here, for example, a pressure distribution function, a damping function, a shaping function or the like may be considered.

Advantageously, the shoe insert is shaped to be thinner in areas where greater flexibility is required than in areas where the flexibility requirements are not so high. By such a configuration, additional components or Unterberechungen, which would possibly lead to a division of the shoe insert, can be avoided.

The shoe insert according to the invention, which can be inserted into and removed from a shoe and which can be produced in innumerable different shapes, but especially in a foot-adapted form, ensures that the wearing of the shoes with and without an inserted shoe insert according to the invention does not occur Makes a difference in comfort, except that the weight of the shoe is increased with the inserted shoe insert.

However, the shoe insert can also be produced in a generally flat or wedge-shaped form. Especially the injection molding of the material mixture of thermoplastic material mixed with metal components allows a great deal of freedom in the shaping of the shoe insert according to the invention.

Furthermore, there is the possibility by the shoe insert according to the invention to use the shoe insert in various shoes. The shoe insert is advantageously shaped so that it fits comfortably in each shoe.

Thus, the user of the shoe insert according to the invention is not limited as in the prior art to a pair of shoes having an increase in weight firmly attached to the shoe. The user of the flexible shoe insert according to the invention can thus bring about an increase in the weight of his shoes as needed and desired, without being limited to always the same shoes or sports.

A further advantage of the shoe insert according to the invention results from the fact that the shoe insert according to the invention can be manufactured separately and independently of the shoes in which it is to be used. This not only has the advantage that the goal to obtain a weight-increased shoe can be achieved more cheaply, but also has the advantage for the user that he in an inexpensive manner, and regardless of a particular shoe model, an increase in weight and the associated desired muscle increase in a simple and affordable way can achieve. He does not need, as in the prior art, to buy a whole pair of shoes to use a pair of shoes with increased weight.

In addition to an injection-molded, flexible shoe insert, other parts of a shoe which are injection-moldable can be made with such a material mixture consisting of a thermoplastic material and metal particles, with the aim that the shoe having such injection-molded parts (shoe inserts), has an increased weight compared to normal shoes. That is, it is u. a. Insoles, inserts for heel reinforcement or other reinforcements, such. B lateral stiffening of boot shafts so producible.

Fig. 1:

Eine perspektivische Ansicht eines erfindungsgemäßen Schuheinlegeteils in Form einer Einlegesohle.

Fig. 2:

Einen Längsschnitt durch die Einlegesohle gemäß Fig. 1 entlang der Linie A-A.

An example of an embodiment of a shoe insert according to the invention with further features will be explained in more detail with reference to the drawings. The drawings show:

Fig. 1:

A perspective view of a shoe insert according to the invention in the form of an insole.

Fig. 2:

A longitudinal section through the insole according to Fig. 1 along the line AA.

In Fig. 1 is a perspective view of a shoe insert 1 in the form of a complete insole 1 shown, which has a weight-increasing layer 2, a good wearing comfort oriented upper layer 3 and a lower layer 4. The comfort-oriented upper layer 3 can consist of Alcantara, which represents a special soft, flexible and warm-looking material. This material is widely used as a topsheet material in conventional non-weight-increasing insoles. The lower layer 4 is advantageously injected directly onto the weight-increasing layer 2.

The weight-increasing layer 2 is made, for example, from a mixture of ethylene-vinyl-acetate (EVA) and steel round material. In this case, the thermoplastic material EVA was matched in the granular state to the particle size of the steel round material used so that the injection-molded insole is flexible and flexible without cracking deformable.

The insole 1, as in Fig. 1 is shown, is formed so that in their toe area, the wall thickness of the weight-increasing layer 4 is thinner than the wall thickness in the heel area. This has the advantage that the insole thus formed in the toe area is very flexible, that is deformable without much effort, and is more stable in the heel area. Such an embodiment allows the insole 1 in areas where a foot rolls over the ball of the foot when walking, running or jumping, ie in the area of the toes and the football, bend easily and still provides the heel a good grip. In this case, the respective area can be designed to be anatomically advantageous.

In another embodiment, the in Fig. 1 shown insole 1 instead of EVA as a thermoplastic material, for example, thermoplastic urethane as a thermoplastic elastomer. However, the present invention is not limited to mixing only thermoplastic material with metal particles, but it is also possible to use a mixture for To use injection molding of the insert according to the invention, which has thermoplastic and thermoelastic material in addition to the metal particles.

In order to obtain optimum flexibility of the shoe insert 1 according to the invention, it has been shown that it is advantageous to use metal particles which are not larger than 1.5 mm.

The addition of metal particles in different proportions ensures that the weight of the shoe insole according to the invention varies. However, it was found that the proportion of the metallic material should not exceed 90% by weight. Further increase in the weight fraction of metal granules would result in brittleness of the flexible shoe insert.

In the preferred embodiment, as in Fig. 1 ethylene-vinyl acetate (EVA) is used because EVA has a particularly good skin compatibility, is not harmful to health and in particular does not form harmful compounds when it comes into contact with perspiration.

Claims (12)

1. Flexible shoe insert (1) for increasing the weight of shoes, which insert extends at least over a partial region of the sole of a foot and causes a wearer of such shoes to have an increased calorie requirement, characterized in that the shoe insert (1) is produced by injection moulding a material mixture comprising at least one thermoplastic material and metal particles in such a way that the concentration of metal particles is higher in the interior of the shoe insert than at its outer surfaces, and it can be inserted into the shoe and removed again from it and has a foot-bed-like or flat form.
2. Flexible shoe insert according to Claim 1, characterized in that it extends over the complete surface of the sole of the foot.
3. Flexible shoe insert according to Claim 1 or 2, characterized in that it has an upper layer (3) which comes into contact with a foot and is formed from soft material that is conducive to wearing comfort.
4. Flexible shoe insert according to one of Claims 1 to 3, characterized in that it has on a side opposite from the sole of the foot a lower layer (4) which comes into contact with the shoe.
5. Flexible shoe insert according to Claims 3 and 4, characterized in that the upper layer (3) and the lower layer (4) completely enclose the shoe insert (1).
6. Flexible shoe insert according to one of Claims 3 to 5, characterized in that the upper layer (3) and/or the lower layer (4) can be moulded onto the shoe insert (1) during the injection moulding of the material mixture.
7. Flexible shoe insert according to one of the preceding claims, characterized in that the thermoplastic material is ethylene vinyl acetate (EVA) or thermoplastic polyurethane.
8. Flexible shoe insert according to one of the preceding claims, characterized in that the metal particles are smaller than 1.5 mm.
9. Flexible shoe insert according to one of the preceding claims, characterized in that the thermoplastic material has a particle size that is made to match the particle size of the metal particles in such a way that, after the injection moulding, the shoe insert (1) can be deformed elastically and without the formation of cracks.
10. Flexible shoe insert according to one of Claims 1 to 9, characterized in that the individual metal particles are enclosed by the thermoplastic material to achieve high flexibility and its outer sides have a virtually closed surface of thermoplastic material.
11. Flexible shoe insert according to one of Claims 1 to 10, characterized in that the metal particles thereof do not exceed 90% by weight.
12. Flexible shoe insert according to one of Claims 3 to 11, characterized in that the material mixture of thermoplastic material and metal particles can be moulded onto at least the upper layer.

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