EP3799754B1

EP3799754B1 - Footwear for cooling and heating a user's foot

Info

Publication number: EP3799754B1
Application number: EP20199948.9A
Authority: EP
Inventors: Teófilo Óscar RIBEIRO GONÇALVES LEITE; Sónia Isabel MATOS SILVA; Joana Catarina TORRES PIMENTA; Filipe Cerqueira Da Silva; José Joaquim POÇAS GONÇALVES; Helena Filipa DA CUNHA FERNANDES; João MOREIRA FERRAZ
Original assignee: Icc Industrias E Comercio De Calcado Sa
Current assignee: Icc Industrias E Comercio De Calcado Sa
Priority date: 2019-10-02
Filing date: 2020-10-02
Publication date: 2022-04-20
Anticipated expiration: 2040-10-02
Also published as: EP3799754A1

Description

TECHNICAL FIELD

The present description concerns a footwear for heating and cooling a user's foot, method of operation and uses thereof. The footwear comprises two thermal regulation systems, namely, a heating system and a cooling system, fully integrated into the footwear structure through an insole and a sole.

BACKGROUND

Commercial cooling systems integrated into footwear, known in the state of the art, undergo passive systems, such as the use of a valve system that, when the shoe flexes during walking, allows the extraction of hot and humid air, from the inside of the shoe into a pumping chamber, renewing the air inside the shoe (fresh air that flows from the outside). Subsequently, when the shoe returns to a horizontal position, the pumping chamber is compressed, leading the hot and humid air to the outside of the shoe. As air is drawn into the shoe only when the heel is raised, water does not enter.
For example, GORE TEX^® SURROUND^® Technology channels the heat and humidity of the feet in all directions (360° breathing capacity) through a microporous membrane and channels present in the sole. The GORE TEX^® membrane provides impermeability and resistance to some chemicals.
The known commercial heating systems are WARMAWEAR^™, DIGITSOLE^® Warm Series, +WINTER, ThermoSoles, Outrek II by TORCH Electrek, Glovii, ThermaCELL^®, THERM IC, HeatSole EXO2. However, these solutions only have the heating functionality.
KR101451719B1 presents a shoe insole having automatic cooling and heating function, which automatically performs a cooling or heating function in accordance to a wearers walking. The shoe insole system having an automatic cooling and heating function comprises: the insole main structure, including an insole member and an adhesive sheet, wherein the insole member includes a heel having a predetermined height to install a blower unit, a recess corresponding to the shape of the blower unit, having an open lower part to accommodate said blower unit in the heel, and the adhesive sheet cut into a shape corresponding to the insole member and attached to a lower open part of the insole member; and the blower unit, which includes a power supply part integrated in the heel of the insole main structure, a walking-sensitive part for its detection and to block or allow an output from the power part, a cooling part to generate cold air and a heating part. The operation to automatically drive the cooling part or the heating part is done in accordance to the detection of the user's foot. Thus, the shoe insole can selectively and conveniently be used according to the seasons or to the user's needs.
KR101742601B1 describes a shoe insole having a cooling and heating function. The shoe insole comprises the following: an insole body inserted into a shoe, supporting the sole of the user's foot; a cooling and heating device installed on the insole body to cool or heat the inside of the shoe, using a thermoelectric element; and an ventilation unit extended from the insole body, which allows the release of heat or cold generated by the thermoelement.
In terms of prior art regarding footwear having heating and cooling systems simultaneously, EP3287031B1 refers to an insole for controlling and adjusting the temperature of the foot. Said insole comprising, from top to bottom: - a first heat-conductive layer, made of fabric; - a second heat insulating layer comprising a Peltier module, wherein said Peltier module comprises a first surface and has a predetermined polarity such that, when the Peltier module is turned on, the first surface of the Peltier module is heated or cooled; - a third heat-dissipating layer, comprising an accelerometer and a control unit connected to said accelerometer and to said Peltier module. Said insole further comprises a first flexible printed circuit, configured to measure the temperature of the foot through at least a first temperature sensor, and the temperature of the first surface of the Peltier module, through another temperature sensor. Said accelerometer is configured to detect an acceleration, and send a signal to the control unit, communicating whether or not an acceleration has been detected in a predetermined period of time, and said control unit is configured, at least, to: - acquire the temperature value detected by the first temperature sensor; - compare the temperature value, detected by the first temperature sensor, with a predetermined temperature range, comprised between the predetermined first and second temperature thresholds; - turn on the Peltier module, when said temperature value is less than the first temperature threshold or greater than the predetermined second temperature threshold; or turn on the Peltier module and reverse the predetermined polarity of the Peltier module, via said H-bridge, when said temperature value is greater than the predetermined second temperature threshold, or less than the predetermined first temperature threshold; - acquire the temperature value detected by said first temperature sensor; - compare said temperature value acquired from said temperature sensor with a third predetermined temperature threshold; - turn off the Peltier module, when said temperature value of said first surface of the Peltier module is higher or lower than the predetermined third temperature threshold.
The inventions described above, within the scope of the prior art, have some limitations when compared to the proposed system, namely: document KR101451719B1 presents a forced air-based cooling system, using fans, promoting only the air circulation and not active cooling, as proposed in the present embodiment.
Documents KR101742601B1 and EP3287031B1 present Peltier modules as heating and cooling systems, the main limitation of which is the integration of said modules to simultaneously promote heating and cooling, and the dimensions of said module cannot be customizable and adaptable to the geometry of the insole.
These facts are described in order to illustrate the technical problem solved by the embodiments of the present document.

GENERAL DESCRIPTION

The present disclosure refers to footwear having cooling and heating systems of the feet comprising an insole, with a heating system and a cooling system, and a sole. Said insole comprises a heating system comprising circuits composed of resistive elements (inks) in the materials that constitute said insole which, by Joule effect, will convert electrical current into heat.
On the other hand, the insole further comprises a cooling system comprising the integration of Peltier modules in the structure thereof. The structure of said insole is multilayered and comprises a thermally conductive layer; a thermal insulating layer and a dissipating layer. This structure is integrated in the sole of the footwear, and further comprises fans and channels for the release of the hot air generated. In the present disclosure, the Peltier module is used to promote cooling, and also comprises the use of a printed heating system, which can present customizable geometries and, also, areas with different temperatures, promoting a more efficient and personalized heating for the user. In addition, the use of printed heating systems allows for longer battery life, as these systems have a lower energy consumption compared to Peltier modules.
The Peltier module can have dimensions between 15x15 - 40x40 mm (width × length), with thicknesses that can vary between 2.5 - 3.5 mm.
In addition, the system presented is autonomous since by detecting the presence of movement it activates the heating/cooling systems, according to what the user has previously defined through the mobile application.
The present invention is defined by a footwear for cooling and heating a user's foot having an insole, according to the appended claim 1.
In a preferred embodiment, the printed heating system comprises: a finishing layer; a printed circuit with resistive inks and a polymeric layer, wherein the printed circuit is integrated in the polymeric layer for receiving the finishing layer on top thereof. The finishing layer is a film for protecting the printed circuit.
In a preferred embodiment, the control module comprises a voltage regulation circuit, a USB or coil charging module for inductive charging.
In a preferred embodiment, the forced air mechanism may include fans or valve systems and pumping chambers. In a preferred embodiment, the forced air mechanism comprises a metal dissipating block.
In a preferred embodiment, the dissipating layer may comprise a metal dissipating block; copper-based woven or non-woven fabric, or heat pipes, or combinations thereof.
In a preferred embodiment, the sole comprises a plurality of channels to force the passage of hot air generated by the Peltier module.
In a non-claimed embodiment, the forced air mechanism is a fan with dimensions between 10 × 10 × 3.8 mm (width, length and thickness) and 40 × 40 × 10 mm, with rotation speeds between 1500 and 4500 rpm, preferably 1700 - 4000 rpm, which may also contain a thermal dissipating block, a pump, fan or suction device, or combinations thereof.
In a preferred embodiment, the sole comprises a cooling fluid circulation system.
In a preferred embodiment, the sole comprises a cooling fluid circulation system distributed over the entire area of said sole.
In a preferred embodiment, the insole comprises a printed heating circuit with resistive inks, sized with a specific geometry for the insole, in order to obtain a uniform heat distribution, said system being directly integrated in a polymeric layer.
In a preferred embodiment, the sole comprises a control module that contains voltage regulation circuits, USB and/or coil charging circuit for inductive charging, a microcontroller, sensors and power supply dimensioned with a specific geometry and functionality, positioned substantially in the heel area of said sole/insole to activate the heating or cooling system.
In a preferred embodiment, the footwear comprises a temperature sensor and an accelerometer to activate the control module and a humidity sensor.
In a preferred embodiment, the heating system comprises a finishing layer, a printed heating circuit and a polymeric layer.
In a preferred embodiment, the printed circuit is positioned between the finishing layer and the polymeric layer. The layers may have specific characteristics, such as: anti-static, anti-microbial, anti-mycotic, anti-odor, breathability, thermoregulation, high memory capacity, high water absorption and desorption capacity, anti-fatigue and impact absorption.
In a preferred embodiment, the printed circuit comprises carbon-based conductive inks, graphene-based conductive inks, silver-based conductive inks, silver and copper conductive inks, or combinations thereof.
In a preferred embodiment, the printed circuit comprises an encapsulation for providing protection against mechanical wear and electrical insulation.
In a preferred embodiment, the encapsulation is done with dielectric inks, lamination of non-conductive membranes, or combinations thereof.
In a non-claimed embodiment, the printed circuit comprises a thickness between 2-55 µm, preferably between 5-20 µm.
In a non-claimed embodiment, the printed circuit comprises an electrical resistivity between 2-40 Ω, preferably between 5-30 Ω.

BRIEF DESCRIPTION OF THE FIGURES

For an easier understanding, figures are herein attached, which represent preferred embodiments which are not intended to limit the object of the present description.

Figure 1 : Representation of the perspective and expanded view of the footwear with the insole with heating system, based on printed circuits, wherein:
1. (1) represents the finishing layer;
2. (2) represents the printed heating circuit;
3. (3) represents the polymeric layer;
4. (4) represents the sole.
Figure 2 : Representation of the perspective and expanded view of the footwear with the insole with cooling system, wherein:
- (6) represents the thermally conductive layer;
- (7) represents the thermal insulating layer;
- (8) represents the dissipating layer.
Figure 3 : Representation of the perspective and expanded view of the footwear with the insole with a cooling system, based on the integration of Peltier modules in the thermal insulating layer, wherein:
- (5) represents the control and power supply module;
- (9) represents the Peltier module;
- (10) represents the forced air mechanism.
Figure 4 : Representation of the perspective and expanded view of the footwear with the insole with cooling system, integrated in the thermal insulating layer, wherein (11) represents the ventilation/dissipation channels and/or fluid circulation system.
Figure 5 : Representation of an embodiment of the cooling system connection scheme.
Figure 6 : Representation of an embodiment of the heating system connection scheme.

DETAILED DESCRIPTION

The present disclosure refers to footwear for cooling and heating a foot comprising an insole, with a heating system and a cooling system, and a sole (4). Said insole comprises a heating system comprising circuits composed of resistive elements (inks) in the materials that constitute said insole which, by Joule effect, will convert electrical current into heat.
In one embodiment, Figure 1 shows a schematic representation of a preferred embodiment where the heating system comprises a finishing layer (1), a printed heating circuit (2) and a polymeric layer (3).
Depending on the type of substrate, the printing of the heating circuit may require a previous treatment of the material, in order to waterproof and standardize the surface thereof. This treatment consists of applying coatings, which can be carried out by two different techniques:

Application of aqueous dispersion films (for example by the Doctor Blade method or 4-sided film applicator) followed by thermal curing;
Lamination of membranes (polyurethane composition or other) under temperature and pressure.

In one embodiment, the substrates that can be used in the manufacture of insoles can have the following characteristics (for example):

Foam composition: polyurethane (PU);
Density: 196 kg/m3;
Elongation: 66 - 62 %;
Tear resistance: 1,7 - 1,6 N/mm
Compression: 7.7 %;
Fatigue resistance: 4.9 - 7.5 %;
Moisture absorption: 243 mg/cm2; desorption: 98 %;
Electrical resistance: 2.6 - 2.7 kΩ.

In addition, circuits are specifically sized for the insole geometry, in order to increase the uniformity of heating in the frontal region of the insole.
In one embodiment, the printed circuits may include the following materials, with electrical resistivities, preferably between 5 to 30 Ω:

carbon-based conductive inks;
graphene-based conductive inks;
silver-based conductive inks;
mixture of the above (carbon/silver)

In one embodiment, the thickness of the printed circuit can be comprised between 5-20 µm (dry).
In one embodiment, after printing the heating circuit on the base substrate, it is necessary to encapsulate it, in order to protect against mechanical wear and electrical insulation. This insulation can be performed by applying coatings with dielectric inks (by film application technologies such as doctor blade) or by laminating non-conductive membranes (applying pressure and temperature). The electronic components (control and power module) are inserted in a cavity of the sole, preferably in the region of the heel and properly protected.
In one embodiment, Figure 2 shows a representation of a preferred embodiment of the footwear with the insole with a cooling system comprising the thermally conductive layer (6); the thermal insulating layer (7) and the dissipating layer (8).
In one embodiment, Figure 3 shows a preferred embodiment of the insole with a cooling system, based on the integration of Peltier modules (9) in the thermal insulating layer (7), and with fans integrated in the sole (4).
The Peltier effect is characterized by the production of a thermal gradient, usually between two opposite faces, when subjected to an electrical voltage. In this sense, Peltier devices can produce a cooling and heating effect (simultaneously, on opposite faces).
In one embodiment, in order to avoid overheating and to promote the correct operation of the Peltier device, the use of heat spreaders is mandatory.
In one embodiment, the insole shall consist of a multilayer structure, specifically 3 layers, namely, (order to consider: from surface to base):

Thermally conductive layer (6): this layer has the function of promoting the uniformity of freshness feel; since the Peltier has relatively small dimensions, so that the cooling is not localized and, eventually, may even cause discomfort, the use of a thermally conductive layer will allow to homogenize the freshness feel; in this layer materials with good thermal conductivity can be used, for example, silver woven/non-woven fabrics (average surface resistivity <0.5 Ω/sq) or graphite sheets (thermal conductivity comprised between 700 -1950 W/(m·K)); or copper and silver sheets (thermal conductivities comprised between 390 - 420 W/(m·K)); not excluding other materials with high thermal conductivity.
Thermal insulating layer (7): this layer, wherein the Peltier shall be integrated, acts in order to insulate the passage of the heat generated from the bottom face, to the top, where it is intended to promote cooling. In this layer, materials such as: polyurethane with insulating properties can be used; not excluding other materials with low thermal conductivity.
Dissipating layer (8): this layer must have a high thermal dissipating capacity, in order to facilitate the extraction of the heat generated on the underside of the Peltier (and which is at the base of the insole). In this layer, materials with high thermal conductivity can be used, for example, copper-based woven/non-woven fabrics (average surface resistivity 0.02 Ω/sq); or other specific structures for thermal conduction, such as for example, heat pipes (thermal conductivity comprised between 1500 - 4.0 × 10⁶ W/(m·K)); not excluding other materials with high thermal conductivity.

In one embodiment, for better results, each face of the Peltier must be fully in contact with the specific face (the face that is in the upper region of the insole in contact with the thermally conductive layer and the face that is in the lower region of the insole in contact with the dissipating layer). In order to optimize the thermal contact/interface between the layers, a paste, adhesive or thermal sponge can be additionally used for coupling the thermally conductive layer and dissipating layer to the upper and lower faces, respectively, considering the order from surface to base.
In one embodiment, Figure 4 shows a preferred embodiment of the footwear comprising a sole (4) with a dissipation system of heat generated by the Peltier module (9), wherein the sole (4) comprises a forced air mechanism (10) positioned substantially below the Peltier module (9), and in contact with the third dissipating layer (8). The sole (4) comprises a plurality of channels (11) to force the hot air generated by the Peltier module (9) to pass outside.
In this way, the present embodiment allows that the system works properly and the sole of the shoe will be optimized so that it promotes the extraction of heat.
In one embodiment, the use of a forced air mechanism (10) is provided (for example a fan) that will be positioned at the base of the Peltier (9), in contact with the dissipating layer (8).
In one embodiment, the forced air mechanism will force the hot air generated by the Peltier, to the outside, through channels created in the sole of the shoe.
In one embodiment, a cooling fluid circulation system may be included, distributed throughout the entire sole area, and which will be in contact with the Peltier (9).
In one embodiment, these systems (forced air mechanism + fluid circulation) can be integrated simultaneously, or only one of them can be used.
In one embodiment, the electronic components (control and power supply module) will be inserted in the sole (4), preferably in the heel region.
In one embodiment, Figures 5 and 6 show a preferred embodiment of the connection schemes for the cooling and heating systems, respectively.
The embodiments described are combinable with each other.
The present invention as defined in the appended claims is of course in no way restricted to the embodiments described herein and a person of ordinary skill in the art can foresee many possibilities of modifying it and replacing technical features with equivalents depending on the requirements of each situation.

Claims

Footwear for cooling and heating a user's foot having an insole, a sole and a control module (5)
configured to activate the heating or cooling of the foot, wherein the insole/sole (4) assembly comprises an independent cooling system and an independent heating system, wherein the insole comprises the heating system and the cooling system and said cooling system comprises
a first thermally conductive layer (6) for temperature uniformity along the insole,

wherein the upper part of the layer is configured to be in contact with the user's foot;

a second thermal insulating layer (7) contacting the lower part of the thermally

conductive layer, wherein the lower part of the insulating layer comprises a recess, positioned substantially in the center of the insole and a Peltier module (9) inserted in the recess;

a third heat dissipating layer (8) to dissipate the heat generated by the Peltier module, configured so as to partially come into contact with said second thermal insulating layer;

wherein said heating system is printed;

wherein the sole comprises a forced air mechanism (10) positioned substantially below the Peltier module and in contact with the dissipating layer in order to actively remove the generated heat,

wherein the control module comprises a temperature sensor and a microcontroller configured to drive the Peltier module and/or the forced air mechanism.
Footwear according to the preceding claim, wherein the heating system comprises:
a finishing layer (1); a printed circuit (2) with resistive inks and a polymeric layer (3),

wherein the printed circuit is printed on the polymeric layer,

wherein the finishing layer coats the printed circuit.
Footwear according to the preceding claim wherein the finishing layer is a film for protecting the printed circuit.
Footwear according to any one of the preceding claims, wherein the sole comprises a plurality of channels (11) to force the circulation of the hot air generated by the Peltier module.
Footwear according to any one of the preceding claims, wherein the forced air mechanism comprises one of the following elements: a fan, a pump, a vent or an air suction device, valves, pumping chambers, or combinations thereof; preferably it further comprises a metal dissipating block.
Footwear according to the preceding claim, wherein the dissipating layer comprises a metal dissipating block; copper-based woven or non-woven fabric, or heat pipes, or combinations thereof.
Footwear according to any one of the preceding claims, wherein the sole comprises a system for circulating a cooling fluid, preferably configured to distribute the fluid throughout the entire sole area.
Footwear according to any one of the preceding claims, further comprising an accelerometer for detecting the movement of the foot.
Footwear according to the preceding claim, wherein the temperature sensor and the accelerometer are configured to activate the control module.
Footwear according to any one of the preceding claims, wherein the sole further comprises a power supply module to supply energy to the heating and cooling system.
Footwear according to the preciding claim, wherein the control and power supply module are arranged in the heel area of said sole/insole.
Footwear according to any one of claims 2-11, wherein the printed circuit of the heating system comprises carbon-based conductive inks, graphene-based conductive inks, silver-based conductive inks, silver and copper conductive inks, or combinations thereof.
Footwear according to any one of claims 2-12, wherein the printed circuit is encapsulated by an encapsulating material selected from dielectric inks, lamination of non-conductive membranes, or combinations thereof.
Footwear according to any one of the preceding claims, wherein the control module further comprises a voltage regulation circuit and a USB or coil charging module for inductive charging.