EP2005851B1 - Shoe, in particular safety shoe or leisure shoe with anti-static function - Google Patents

Abstract

The shoe consists of a sole with a foot rest and outer sole area (12). The foot rest is formed as single piece with the sole which is made up of plastic. An integrated channel (13) is provided extending from the foot rest up to the outer sole area, which is filled with an electrically conducting material (14).

Description

The invention is based on a shoe, in particular a safety shoe or a leisure shoe with an antistatic function, according to the preamble of claim 1.

Safety shoes are often made entirely of plastic to meet the requirements of technological properties, hygiene and safety regulations. With such plastics, safety shoes can be provided from an antibacterial material which has stain-resistant properties and is machine washable. In addition, safety shoes made of plastic have good wearing properties and are characterized by a low weight. For example, polyurethane has prevailed as a material in safety shoe technology.

The problem with shoes made of such a plastic, the electrostatic charge of the shoe wearer and the risk of electrical short-circuit currents through the shoe wearer. The associated discharges are uncomfortable for the wearer and sometimes painful. Especially when working with semiconductors, micro-chips, and other sensitive components, static discharges can even have serious consequences until component destruction. In the health sector too, sensitive devices are being used, especially in the surgical area, where static discharges can lead to malfunctions and cause disturbances with fatal consequences.

To avoid such discharges such material can be made antistatic by appropriate composition and thus a required technological property. However, the often associated low resistance to abrasion, to heat and insufficient cut resistance are undesirable. However, the latter properties in particular limit the scope of such shoes considerably.

In the utility model DE 26 10 170 U1 For example, a shoe is proposed having a multi-layered sole comprising a midsole of antistatic material and a durable outsole, the midsole being provided with guide bridges passing through the outsole.

In the utility model DE 35 16 916 U1 is described an insole for a safety shoe to reduce the electrostatic charge of the shoe wearer. The insole is penetrated by electrically conductive inserts which form a conductive connection between the foot of the shoe wearer resting against the upper side of the insole and an electrically conductive outsole of the shoe. It is proposed that the inserts are formed from plugs of electrically conductive elastomeric material, preferably rubber or rubber, which pass through the insole, are provided exclusively in the forefoot region of the insole and terminate flush with the insole.

The WO 2005/122814 A as well as the DE 21 47 904 A disclose a safety shoe comprising a sole with a footrest and an outsole region, the footrest being formed integrally with the sole of a plastics material, at least one continuous "channel extending from the footrest to the outsole region being provided with one electrically conductive element Material is filled.

The production of such shoes or insoles for the production of shoes with antistatic effect, however, is complicated and thus costly.

The object of the invention is to provide an improved safety shoe, which has antistatic properties and is particularly simple and inexpensive to produce.

The object is achieved by the features of the main claim. Favorable embodiments and advantages of the invention will become apparent from the other claims and the description.

An inventive safety shoe or leisure shoe with anti-static function comprises a sole with a footrest and an outsole area, wherein the footrest is formed integrally with the sole of a plastic, and wherein at least one continuous, ranging from the footrest to the outsole area channel is provided, with a electrically conductive material is filled. As a footrest below the area is referred to, on which the foot of the user rests directly. Advantageously, the foot of the user is in direct electrical contact with the electrically conductive material, thereby preventing a static charge of the user in a simple manner. The electrically conductive material is embedded in a casting material. The electrically conductive material is encapsulated or encapsulated in the channel. This allows particularly rapid and inexpensive production processes such as injection molding. In addition, in this production method of great advantage that the electrically conductive material can be flush mounted in the channel, which increases the comfort while maintaining the favorable antistatic effect.

The electrically conductive material may preferably comprise antistatic fibers, in particular carbon fibers or a foam which contains carbon fibers, for example coated with carbon fibers. These may be embedded in the channel such that the carbon fibers are flush with both the foot-facing surface of the footrest and the floor-facing surface of the outsole region. Thus, the conductive material formed of carbon fibers is favorably barely noticeable to the user and provides the required frictional contact with the ground on the tread surface of the outsole without creating a troublesome bump.

It can also be provided that the electrically conductive material is formed from electrically conductive fibers, for example electrically conductive plastic fibers and / or a plastic filled with electrically conductive particles and / or a conductive fabric.

The channel may be punched out of the sole region of the shoe and filled with the conductive material in the manner of a plug. In an advantageous variant, the channel has a diameter of less than 1 cm, preferably about 5 mm, and is arranged perpendicularly between a plane of the footrest and a plane of the outsole region. The plug formed from the conductive material has a dimension adapted to the diameter of the channel. Thus, together with the conductive material, a preferred conductivity channel is formed with which the foot of the user is in electrical contact when the shoe is worn as intended.

In a simple embodiment, a channel may be formed per shoe, which is expediently arranged in the ball area in order to ensure the most secure possible ground contact. In a preferred variant, two channels per shoe may be formed, wherein a first channel in the ball area and a second channel in the heel area is arranged.

Alternatively, a plurality of channels can be provided, which are distributed over the entire outsole area. In a regular, pattern-like distribution, a designerischer effect can be achieved in addition.

As the base material for the shoe, a plastic may be provided, preferably a cushioning and shock-absorbing foam of closed cells, which is marketed in the US under the trade name "ComtoTek". The entire shoe is preferably made in one piece from this material. The structure of billions of small bubbles is preferably extremely resistant and abrasion-resistant, while providing a high level of comfort for the user with long durability of the sole. In addition, it is favorable that the shoes have only a low weight of about 180g per pair in size M. At the same time all the requirements for a safety shoe are met with this base material, because the shoe is dirt-repellent and easy to clean, because he machine washable. In addition, the shoe is advantageously non-slip, which can be additionally reinforced by a suitable structuring on the tread. In addition, shoes made of this material conveniently leave no annoying marks on floor coverings. The antistatic function according to the invention offers a particularly favorable and easy to produce additional function.

In a preferred embodiment, the electrically conductive material is formed from a carrier material formed from a silicone compound, for example from a silicone rubber, into which nano-graphite or graphite dust and / or graphite fibers is introduced as an electrically conductive admixture. In particular, short graphite fibers can form a favorable contact bridge to the silicone compound. Also conceivable is the introduction of nano-graphite or graphite dust. In this case, graphite fibers have particularly advantageous bonding properties with the silicone rubber.

Before the graphite fibers are mixed with the carrier material, a felting of the graphite fibers is expediently produced in order to produce a conductive structure. Advantageously, the fibers are wetted in a little time-consuming process step, mixed with a weak binder and then mechanically mixed. The blending thus prepared conveniently produces a conductive matrix. The thus formed electrically conductive admixture is then incorporated before vulcanization in the mass to be vulcanized and can be introduced as one-component or as a two-component material, wherein two-component means that before further processing, a curing agent is added, while added in the one-component material no hardener becomes.

Subsequently, the thus prepared material mixture can be introduced into the channel of the shoe, in particular injected. An advantage of the injection method is that the material mixture is crosslinked or vulcanized in the mold. The material mixture thus beneficially assumes the shape of the channel or the recess. Another process step in the form of a gluing the conductive plug with the sole can be advantageously saved. In addition, the compound thus formed is very homogeneous and has particularly favorable connection properties in the channel or with the sole. It is particularly advantageous that the type of support material, eg silicone rubber, with the introduced electrically conductive admixture is definable in such a way that both the density and the expansion factor (modulus of elasticity) are exactly matched to the material from which the shoe is made, can be adjusted. Advantageously, this no longer leads to unwanted loosening of the plug from the channel, because any disadvantageous differences with respect to the density ratio and the elasticity of the plug and shoe material can be compensated. The plug thus formed thus holds even heavy loads when using the shoe, for example by stretching and deformation, stood and remains safe and stable in the channel. Likewise, the tightness of the shoe is guaranteed even in continuous use.

Another advantage is that, depending on the addition of the electrically conductive admixture of the electrical resistance and thus the conductivity of the silicone rubber is adjustable. Unlike a solid material is in the presently adjustable material mixture is no longer dependent on predetermined physical properties of the introduced electrically conductive admixture, so that a need-based customization is possible. The electrical volume resistance is thus advantageously metered.

A proportion of less than 10% by weight (weight percent) of the electrically conductive admixture, in particular of graphite fibers, is preferably introduced into the silicone material, more preferably 1-3% by weight, in the range of electrically conductive shoes having a lower electrical resistance As antistatic shoes, this weight percentage can vary even more.

In a particularly preferred embodiment, in the at least partially formed from the electrically conductive material plug, an electrical resistance component with a body which represents a well-defined resistance introduced. For this purpose, a commercially available electrical component can be used, which can be suitably deformed, for example by bending and / or roles that it is adapted to the size of the channel. Subsequently, it is completely enveloped by the silicone rubber carrier material mixed with the electrically conductive admixture and introduced into the channel, as described above. Particularly preferably, the electrical resistance component can be embedded or encapsulated in the electrically conductive material. Advantageously, the component is thus arranged moisture-tight in the electrically conductive silicone mixture. The body of the electrical resistance component may comprise a first and a second connection part, which is guided as close as possible to the surface of the plug. Advantageously, an electrical parallel connection is thus produced between the plug and the resistance component. It is particularly advantageous because the electrical conductivity of the shoe is precisely controlled. In a possible interruption of the electric guide bridge formed by the plug in the sole can thus be favorably prevented that the electrical conductivity decreases seamlessly. In addition, the fact that the component is arranged in the plug, the wearing comfort of the shoe is not affected.

The invention is described below by way of example, without limitation of generality, with reference to exemplary embodiments illustrated in drawings.

Fig.1

eine Unteransicht auf eine Laufsohle einer besonders günstigen Ausführungsform des erfindungsgemäßen Schuhs ,

Fig. 2

eine Schnittdarstellung gem. der Linie A-A in Fig. 1; und

Fig. 3

eine besonders bevorzugte Ausführungsform eines in einen Kanal des Schuhs angeordneten Pfropfens.

Show it:

Fig.1

a bottom view of an outsole of a particularly favorable embodiment of the shoe according to the invention,

Fig. 2

a sectional view acc. the line AA in Fig. 1 ; and

Fig. 3

a particularly preferred embodiment of a arranged in a channel of the shoe plug.

In the following figures, functionally identical elements are numbered with the same reference numerals.

Fig. 1 shows a bottom view of a sole, in particular on an outsole region 12 of a safety shoe 10 with antistatic function, and in FIG. 2 is a sectional view of a safety shoe 10 along the line II-II in Fig. 1 shown.

The safety shoe 10 is made of a plastic and preferably formed in one piece. Both on the outsole region 12 and on the footrest 11 not shown corrugations may be provided, which provide a better grip and a high skid resistance.

In the outsole region 12, two continuous channels 13a and 13b are provided, which extend from the footrest 11 to the outsole region 12, wherein the channels 13a and 13b are each filled with an electrically conductive material 14. The electrically conductive material 14 comprises carbon fibers. The channels 13a and 13b are each arranged perpendicularly between a plane of the footrest 11 and a plane of the outsole region 12 and, together with the conductive material 14, in each case form an electrical conductivity channel. Each channel 13a, 13b is each formed so that the foot of the user is in direct electrical contact with the conductivity channel and thus avoids electrostatic charging of the shoe wearer.

In a preferred embodiment, the first channel 13a is provided in the heel area 16 and the second channel 13b is provided in the ball of the foot area 17.

Fig. 3 shows a particularly preferred embodiment of a arranged in a channel 13 of the shoe 10 plug 22, which is at least partially formed of a conductive material 14. The channel 13 is arranged perpendicularly between a plane of the footrest 11 and a plane of the outsole region 12. The plug 22 is flush with its surfaces with the levels of the footrest 11 and the outsole region 12 flush. The plug 22 is formed in its upper region near the footrest and the lower region close to the outer surface of a conductive material 14, which consists of a carrier material of silicone rubber, in which, for example, graphite fibers are introduced as the conductive material 14. The conductive material 14 is, for example, in the amount such that the plug 22 is set to low impedance. In a central region of the plug 22 is a insulating or high-resistance layer 23, into which an electrical resistance component 18 with a body 19, which represents a well-defined ohmic resistance, is introduced. The electrical resistance component 18 may be formed of ceramic, a metal or a plastic. A resistance of the electrical resistance component 18 is defined in a desired ESD range (Electrostatic Discharge range) adjustable. The insulating layer 23 may be formed of a non-conductive silicone rubber or a sealing ring. The body 19 of the electrical resistance component 18 comprises, for example, a first connection part 20 and a second connection part 21, wherein the first and the second connection part 20 and 21 may be formed from a wire or a metallic surface. With this arrangement, an electrical parallel connection between the plug 22 and the electrical resistance component 18 can be produced, as a result of which the electrical conductivity of the shoe 10 can be precisely controlled by the resistance component 18. In a possible interruption of the guide bridge formed by the plug 22 can thus be conveniently prevented that the electrical conductivity drops seamlessly.

In a favorable variant, the insulating layer 23 can be filled with the resistance component 18 in the full width of the channel 13. The resistance component 18 can also be formed from a conductive foam element. Thus, there are more variable design options.

LIST OF REFERENCE NUMBERS

10

safety Shoe

11

footrest

12

Outsole area

13a, 13b

channel

14

conductive material

16

heel

17

football field

18

electrical resistance component

19

body

20

first connection element

21

second connection element

22

Graft

23

insulating layer

Claims (12)

1. Shoe (10), in particular a safety shoe or leisure shoe with anti-static function, comprising a sole having a foot support (11) and an exterior sole region (12), wherein the foot support (11) is formed together with the sole from a single piece of plastic material, wherein at least one continuous channel (13, 13a, 13b) extends from the foot support (11) through to the exterior sole region (12) and is filled with an electrically conductive material (14), characterised in that the electrically conductive material (14) is enclosed in the channel (13, 13a, 13b) by injection moulding or casting.
2. Shoe according to Claim 1, characterised in that the electrically conductive material (14) is embedded in a casting material.
3. Shoe according to one of the foregoing claims, characterised in that the channel (13, 13a, 13b) is formed in such a way that the foot of the user is in electrical contact with the channel (13, 13a, 13b).
4. Shoe according to one of the foregoing claims, characterised in that two channels (13a, 13b) are formed, whereby the first channel (13a) is formed in the area of the heel (16) and the second channel (13b) is formed in the area of the ball of the foot (17).
5. Shoe according to one of the foregoing claims, characterised in that several channels (13, 13a, 13b) are distributed over the whole of the exterior sole region (12).
6. Shoe according to one of the foregoing claims, characterised in that the electrically conductive material (14) incorporates carbon fibres.
7. Shoe according to one of the foregoing claims, characterised in that the electrically conductive material (14) consists of a plastic material filled with electrically conductive particles.
8. Shoe according to one of the foregoing claims, characterised in that the electrically conductive material (14) consists of a carrier material composed of a silicone compound, into which an additive of electrically conductive graphite fibres and/or graphite dust has been incorporated.
9. Shoe according to Claim 8, characterised in that the silicone compound that incorporates the graphite fibres and/or the graphite dust is vulcanised in the channel.
10. Shoe according to one of Claims 8 or 9, characterised in that a proportion of less than 10% by weight, preferably of 1-3% by weight, of electrically conductive additive, particularly graphite fibres, is incorporated in the silicone compound.
11. Shoe according to one of the foregoing claims, characterised in that an electrical resistor component (18) with a precisely defined ohmic resistance is incorporated in the plugs (22) that consist at least in part of electrically conductive material (14).
12. Shoe according to one of the foregoing claims, characterised in that the material for the shoe (10) consists of a plastic material.

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