Patent Description:
The following background information is a description of the background of the present invention, which thus not necessarily has to be a description of prior art.

One of our times big challenges is to reduce the overall energy consumption in the world. In many parts of the world, houses, apartments, offices, shops, factories and/or other public or non-public spaces, need to be heated in order to provide an acceptable environment for people spending time in these spaces. Such heating thus needs to provide a comfortable temperature at the same time as the energy consumption should be kept at a minimum.

Underfloor heating may be used for reducing the energy consumption at the same time as an acceptable temperature/environment is provided. It is nowadays common to install underfloor heating using warm water or electricity as a heat source when stone and/or ceramic tiles are used for covering the floor. Also, underfloor heating may be used when wooden floors, such as e.g. parquet flooring, are used for covering the floors.

Traditionally, the heat used for providing the underfloor heating has been created by warm water flowing in pipes/tubes under the floor boards and/or by electricity flowing through resistance in sheet materials arranged under the floor boards. Such a known solution is described in <CIT>, in which a mat/sheet "denoted heating device <NUM>" in the document is arranged under a "floor covering <NUM>", i.e. under the actual floor boards. These pipes/tubes and/or sheet materials are thus arranged underneath the wooden floor, or underneath the stone and/or ceramic tiles. These traditional solutions have a disadvantage in that they are not very efficient in providing the heat into the space where it is actually needed, i.e. into the space above the wooden floor, and/or above the stone and/or ceramic tiles. This is due to the fact that the heat is created underneath the wooden floor, or underneath the stone and/or ceramic tiles, and thus needs to be transported through the entire wooden floor, and/or through the entire stone and/or ceramic tiles to reach the space where the e.g. people are to be present, i.e. to reach the space which should be heated. Also, a large part of the created heat is transported in the opposite direction, i.e. away from the wooden floor, or the stone and/or ceramic tiles, which also means away from the space which should be heated. Thus, a lot of the created heat is lost in such traditional heating systems, wherefore the heating system is inefficient and wastes energy.

In a prior art solution shown in <CIT>, a flooring board is instead provided with an embedded heating foil within the board, which is arranged for creating heat when being supplied with electrical energy. Hereby, the created heat is much more efficiently provided to the space in which it is needed, since the heat is created within the actual flooring board, instead of underneath it.

<CIT>, <CIT> and <CIT> disclose other prior art solution for flooring boards with heating arranged to be coupled to adjacent flooring boards.

The flooring board shown in <CIT> has, however, a number of problems related to the power supply to the flooring boards. The flooring board has electrical connecting means arranged on the grooves and tongues of the quick coupling joints being used for mechanically coupling the flooring board together with other flooring boards. Since the electrical connecting means are arranged on the grooves and tongues of the joint, the electrical connecting means will also experience small movements when pressure is applied on the flooring boards. The parts of the joints, i.e. the grooves and the tongues of the joints, move slightly every time for example a person walks on the flooring boards. Hereby, the electrical connecting means in <CIT> will become worn out after some use. Also, even a lost contact may result from the wear of the electrical connecting means, whereby the heating function is lost. Also, a short circuit may be caused by the wear of the electrical connecting means, which may be hazardous due to e.g. a risk of fire. These possible problems are of course very unfortunate, especially for a floor having a long expected life time. Such a floor may have to be exchanged after a considerably shorter time than expected due to a malfunctioning heating function of the floor.

It is therefore an object of the present invention to provide a panel, an electrical end connector, a method, and a heating system that solve at least some of the above stated problems and/or disadvantages.

The object is achieved by the above mentioned panel according to the characterizing portion of claim <NUM>. The panel may in this disclosure be understood to correspond to a panel assembly comprising the panel and an electrical end connector mounted on/attached to the panel for coupling the panel to an adjacent panel.

Thus, the first and second end panel coupling means include first and second end panel grooves, respectively, the first and second end panel grooves at least partly extending between the first and second opposite longitudinal sides, and the at least one electrical end connector is arranged in one or more of the first and second end panel grooves.

According to an embodiment of the present invention, the at least partly resilient portion of the at least one electrical end connector is arranged to protrude at least partly from the one or more of the first and second end panel grooves in its relaxed state.

According to an embodiment of the present invention, the at least partly resilient portion is arranged to protrude at least partly more than a width Wend_con of the at least partly resilient portion of the at least one electrical end connector.

According to an embodiment of the present invention, the at least partly resilient portion of the at least one electrical end connector is arranged to be pressed into at least one of the first and second end panel grooves by at least one of first and second end panel coupling means of an adjacent panel when the panel is being coupled to the adjacent panel.

According to an embodiment of the present invention, the at least partly resilient portion of the at least one electrical end connector is arranged to relax into, i.e. to at least partly return towards its relaxed state by relaxing into, at least one of the first and second end panel grooves of the adjacent panel when the panel is coupled to the adjacent panel.

According to an embodiment of the present invention, the at least partly resilient portion of the at least one electrical end connector is arranged to be snapped into at least one of first and second end panel grooves of the adjacent panel, thereby mechanically locking the panel to the adjacent panel.

According to an embodiment of the present invention, the first and second end panel grooves have a height Hend_groove essentially equal to a height Hend_con of the at least partly resilient portion of the at least one electrical end connector; Hend_groove = Hend_con.

According to an embodiment of the present invention, at least one of the first and second end panel grooves have a first depth Dend_groove1 essentially equal to or larger than a width Wend_con of the at least partly resilient portion of the at least one electrical end connector; Dend_groove1 ≥ Wend_con.

According to an embodiment of the present invention, at least one of the first and second end panel grooves have a second depth Dend_groove2 smaller than a width Wend_con of the at least partly resilient portion of the at least one electrical end connector; Dend_groove2 < Wend_con.

According to an embodiment of the present invention, the at least partly resilient portion of the at least one electrical end connector includes a first and a second electrically conducting tongue.

According to an embodiment of the present invention, the first and second electrically conducting tongues of the at least partly resilient portion are arranged to be in electrical contact with the heat providing layer of the panel and with a corresponding heat providing layer of an adjacent panel being coupled to the panel.

According to an embodiment of the present invention, the heat providing layer of the panel includes first and second electrically conducting parts adjacent to at least one of the first and second end panel grooves.

According to an embodiment of the present invention, the first and second electrically conducting tongues of the at least partly resilient portion are arranged to be in electrical contact with the first and second electrically conducting parts, respectively, of the heat providing layer of the panel and with corresponding first and second electrically conducting parts, respectively, of a corresponding heat providing layer of an adjacent panel being coupled to the panel.

According to an embodiment of the present invention, the first and second electrically conducting tongues are at least partly wave-formed.

According to an embodiment of the present invention, the at least partly resilient portion of the at least one end connector is arranged to be located closer to the first end portion than to the second end portion, or vice versa.

According to an embodiment of the present invention, the at least one end connector has a length L and a most protruding part of the at least partly resilient portion of the at least one electrical end connector is arranged to be located a first length L1 from at least one of the first and second end portions, wherein a ratio between the first length L1 and length L is at least one in the group of: <MAT> <MAT>and <MAT>.

According to an embodiment of the present invention, the at least partly resilient portion of the at least one electrical end connector includes a resilient material.

According to an embodiment of the present invention, the at least partly resilient portion of the at least one electrical end connector includes first and second portions being resiliently connected to each other.

According to an embodiment of the present invention, the first and second portions of the at least partly resilient portion are resiliently connected to each other by means of at least one in the group of:.

According to an embodiment of the present invention, at least one of the first and second portions of the at least partly resilient portion includes a resilient material.

According to an embodiment of the present invention, the first and second portions of the at least partly resilient portion include first and second electrically conducting tongues, respectively.

According to an embodiment of the present invention, at least first and second longitudinal grooves are arranged in the base layer from the first end side to the second end side and facing the heat providing layer, the at least first and second longitudinal grooves being arranged in parallel with, and having at least first and second distances to the first and second longitudinal sides, respectively.

According to an embodiment of the present invention, the panel further includes:.

According to an embodiment of the present invention, at least one insulating core is included in the base layer, the at least one insulating core having heat insulating and/or sound absorbing properties.

According to an embodiment of the present invention, the heat providing layer is arranged at a heat depth Dheat from the visible surface <NUM> being one in the group of:.

The above mentioned object is also achieved by the above mentioned electrical end connector. The electrical end connector being insertable into one or more of the first and second end panel grooves of the first and second end panel coupling means of a panel and characterized by the at least one electrical end connector including first and second end portions and an at least partly resilient portion located between the first and second end portions, the at least partly resilient portion at least partly including an electrically conductive material and at least partly protruding from the one or more of the first and second end panel coupling means, thereby providing an electrical connection between the heat providing layer of the panel and a corresponding heat providing layer of at least one adjacent panel coupled to the panel.

When the panel and an adjacent panel are mechanically coupled together, the at least partly resilient portion of the electrical end connector is, according to various embodiments, inserted/received in first and second end panel grooves of both the panel and the adjacent panel, whereby the at least partly resilient portion of the electrical end connector provides for the electrical connection between the heat providing layers of the panel and of the adjacent panel.

The above mentioned object is also achieved by a method for coupling a panel to a corresponding adjacent panel characterized in:.

The above mentioned object is also achieved by a heating system. The heating system includes:.

The panel and heating system according to the present invention provide for an energy efficient and durable heating of essentially all sorts of spaces.

By integrating the heat providing layer into a construction panel, such as e.g. a flooring panel, a wall panel and/or a ceiling panel, it is possible to efficiently, precisely and reliably regulate the indoor climate/temperature in spaces delimited by a floor, walls and a ceiling at least partly including such panels.

The heat providing layer is arranged very close to the space to be heated, since it is located directly under the covering/decorative layer. Hereby, the created heat may be very efficiently transported to the space to be heated when the panel according to the present invention is used. By this efficient heat transportation to the space to be heated, the consumption of electric energy being used for creating the heat is minimized.

The panel according to some embodiments of the present invention is cuttable in the sense of being possible to cut off and still be used for laying floors. This is due to the fact that the locations of the first and second longitudinal grooves are well defined, which also results in a well-defined placement of the first and second electrical power supply end connectors placed in the first and second grooves.

By usage of the present invention, a secure and reliable power supply to the panel is assured. Also, the design of the electrical end connector according to the present invention simplifies mechanical coupling of panels together, at the same time as a stable electrical coupling is provided.

Also, the electrical end connector of the panel according to the present invention provides for a reliable and secure electrical contact to adjacent panels. Hereby, electrical energy to be used for creating the heat in the heat providing layer reliably reaches each one of mechanically and electrically coupled panels, and therefor also reaches the heat providing layers of each one of the panels.

The panel according to the present invention may be produced and installed cost efficiently. Since the heat may be created by use of low voltages, such as <NUM>-<NUM> Volts, e.g. approximately <NUM> Volts or approximately <NUM> Volts, the panels may even be installed by a layman, i.e. by a non-professional. Thus, by installation of the panels according to the present invention, there may not be a need for an electrician to be present, depending on laws and regulations where the panel is to be installed/used, which dramatically reduces the total cost for an end user, e.g. a house owner. Prior art electrical underfloor heating systems are often driven by much higher voltages, e.g. <NUM> Volts, which must be installed by a certified electrician.

Some known underfloor heating systems include a lower voltage mat/sheeting creating the heat, which is arranged under the wooden floor or underneath the stone and/or ceramic tiles. One such example is the above-mentioned heating device <NUM> in <CIT>, which is arranged under the floor covering <NUM>. This arrangement results in considerable energy losses as described above. Also, this prior art lower voltage mat/sheeting is often difficult to properly install, wherefore a skilled person often must adapt e.g. the size of the mat/sheeting to fit the area to be covered by the floor. This increases the costs for installation of the floors.

The panel according to the present invention, however, already itself includes the heat providing layer, and does thus not need any heat creating mats to be installed underneath it.

As a non-limiting example, a power per floor area in an interval of approximately, <NUM>-<NUM> W/M<NUM>, or <NUM>-<NUM> W/m<NUM> may be used for creating the heat. The used power per floor area may be seen as a balance between differing characteristics for the floor and/or heating. Higher power generally results in shorter heat providing circuits, which is an advantage when cutting off the panels since the part of the panel without heating due to the cutting off becomes small. However, for lower powers per floor area, the resistances of the heat providing circuits are less critical than for higher powers and lower resistances.

Detailed exemplary embodiments and advantages of the panel, the heating system, and the method according to the invention is hereafter described with reference to the appended drawings illustrating some preferred embodiments.

Embodiments of the invention are described in more detail with reference to attached drawings illustrating examples of embodiments of the invention in which:.

<FIG>, <FIG>, <FIG>, and <FIG> schematically show views of a panel <NUM> and/or an electrical end connector <NUM> according to various embodiments of the present invention.

As is shown e.g. in <FIG>, the panel <NUM> is delimited by a first longitudinal side <NUM> and by a second longitudinal side <NUM> being opposite the first longitudinal side <NUM>. The panel <NUM> is also delimited by a first end side <NUM> and by a second end side <NUM> being opposite the first end side <NUM>.

The first longitudinal side <NUM>, the second longitudinal side <NUM>, the first end side <NUM>, and the second end side <NUM> may be provided with panel coupling means, such as a groove/female and tongue/rabbet forming e.g. "click joints" <NUM>, <NUM>, <NUM>, <NUM>, respectively. The panel coupling means <NUM>, <NUM>, <NUM>, <NUM> are, according to an embodiment, arranged in the base layer <NUM> at the first <NUM> and second <NUM> longitudinal sides of the panel <NUM>, and at the first <NUM> and second <NUM> end sides of the panel <NUM>, for mechanically coupling the panel <NUM> to at least one adjacent panel <NUM>, <NUM>,. <NUM>, i.e. to at least one other corresponding panel <NUM>, <NUM>,. , <NUM> (as shown in <FIG>), where the at least one other corresponding panel is provided with corresponding panel coupling means, in a known way.

The panel <NUM> further includes a base/core layer <NUM> and a covering/visual layer <NUM>. The covering/visual layer <NUM> has a surface <NUM> possibly being visible from the space to be heated, i.e. from within the room in which the panel <NUM> covers a floor, wall and/or ceiling. The covering/visual layer <NUM> may have a suitable appearance/look, including colors and/or patterns.

The panel <NUM> further includes a heat providing layer <NUM> attached to the base layer <NUM>, i.e. arranged between the base layer <NUM> and the covering/visual layer <NUM>. This also means that the heat providing layer <NUM> is arranged very close to the space to be heated, i.e. directly underneath the thin covering/visual layer <NUM>. The heat providing layer <NUM> may include essentially any material being electrically conducting and having an electrical resistance suitable for creating heat, i.e. an increased temperature, when current flows through the material. The material may be formed as a heat generating element, which may have a large number of shapes. For example, the heat providing layer <NUM> may comprise printed electronics, a film, one or more resistors, a sheet, a tape, a paint, or may have essentially any other shape or form suitable for creating heat through its electrical resistance and for being included in the panel <NUM> according to the present invention. Thus, for example, the heat providing layer <NUM> may comprise at least one heat generating element including printed electronics having an electrical resistance, at least one film having an electrical resistance, and/or one or more resistors having an electrical resistance.

As a non-limiting example, it may be mentioned that, when the electric energy has a voltage of <NUM> V, i.e. when the electrical energy providing arrangement delivers a voltage of <NUM> V is used as power supply, <NUM> W/m<NUM> may be created by the heat providing layer <NUM> according to an embodiment. The time constant for the temperature increase at the covering layer may be short, in the area of minutes, and a temperature increase of e.g. <NUM> may be quickly achieved.

The voltage drop increases with the squared length of the floor. For shorter floors, e.g. floors having a length shorter than <NUM>, the voltage drop has little effect on the created heat. However, for longer floors, e.g. floor longer than <NUM>, the voltage drop may noticeably affect the produced heat.

According to an embodiment of the present invention, the heat providing layer <NUM> is arranged at a heat depth Dheat from the visible surface <NUM> in an interval of <NUM> - <NUM>, <NUM> - <NUM>, or <NUM> - <NUM>, and/or at a depth of <NUM>. This then also means that the covering layer <NUM> has a thickness Tcov being equal to the heat depth Dheat; Tcov = Dheat; which results in an efficient transport of heat energy into the space to be heated, since the heat providing layer <NUM> is very close to the heated space.

According to an embodiment of the present invention, the layers of the panel <NUM>, i.e. the base layer <NUM>, the heat providing layer <NUM> and the covering layer <NUM> are attached/fixed to each other by use of an adhesive, such as e.g. a glue.

The panel <NUM> according to the present invention may according to some embodiments include a first longitudinal groove <NUM> arranged in parallel with, and having at least a first distance <NUM> to, the first longitudinal side <NUM>, and a second longitudinal groove <NUM> arranged in parallel with, and having at least a second distance <NUM> to, the second longitudinal side <NUM> (as shown in <FIG> and <FIG>). The first <NUM> and second <NUM> longitudinal grooves may be arranged in the base layer <NUM> of the panel <NUM> and may extend from the first end side <NUM> to the second end side <NUM>. The first <NUM> and second <NUM> longitudinal grooves face the heat providing layer <NUM>, i.e. the opening/aperture of the grooves are directed towards the heat providing layer <NUM>. The first <NUM> and second <NUM> longitudinal grooves may be used to provide an electrical connection between the heat providing layer <NUM> of the panel <NUM> and an electrical energy providing arrangement <NUM>, as will be further described below with reference to <FIG>.

The panel <NUM> according to the present invention further includes at least one electrical end connector <NUM> arranged at one or more of the first end panel coupling means <NUM> at the first end side <NUM>, and the second end panel coupling means <NUM> at the second end side <NUM>. More in detail, the first <NUM> and second <NUM> end panel coupling means include first <NUM> and second <NUM> end panel grooves, respectively. These first <NUM> and second <NUM> end panel grooves at least partly extend between the first <NUM> and second <NUM> opposite longitudinal sides of the panel. The at least one electrical end connector <NUM> is arranged in one or more of the first <NUM> and second <NUM> end panel grooves, respectively. <FIG> shows an embodiment where an electrical end connector <NUM> is arranged at the first <NUM> coupling means at the first end side <NUM> of the panel <NUM>.

The at least one electrical end connector <NUM> includes first <NUM> and second <NUM> end portions and an at least partly resilient portion <NUM> located between the first <NUM> and second <NUM> end portions. The at least partly resilient portion <NUM> is at least partly electrically conductive, i.e. at least partly include an electrically conducting material, such as e.g. a suitable metal. Thus, the at least partly resilient portion <NUM> may include one or more sections being resilient, and may also include one or more non-resilient sections. Further, the at least partly resilient portion <NUM> may include one or more sections of a conductive material, and may also include one or more sections of a non-conductive material. The at least partly resilient portion <NUM> is further at least partly protruding from the one or more of the first <NUM> and second <NUM> end panel coupling means when being arranged at the one or more of the first <NUM> and second <NUM> end panel coupling means. Thus, one or more sections of the at least partly resilient portion <NUM> may protrude from the one or more of the first <NUM> and second <NUM> end panel coupling means when being arranged therein.

These features make it possible for the at least partly resilient portion <NUM> to provide an electrical connection between the heat providing layer <NUM> of the panel <NUM> and a corresponding heat providing layer <NUM>' of at least one adjacent panel <NUM>, <NUM> coupled to the panel <NUM>. Thus, the at least partly resilient portion <NUM> is arranged to make the heat providing layers <NUM>, <NUM>' of at least two adjacent panels <NUM>, <NUM>, <NUM> (shown e.g. in <FIG>) electrically connectable to each other when the panels <NUM>, <NUM>, <NUM> are mechanically coupled to each other.

According to embodiments of the present invention, schematically illustrated e.g. in <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, the first <NUM> and second <NUM> end panel coupling means include first <NUM> and second <NUM> end panel grooves, respectively. The first <NUM> and second <NUM> end panel grooves are at least partly extending between the first <NUM> and second <NUM> opposite longitudinal sides and being arranged for at least partly receiving the at least one electrical end connector <NUM>. In other words, the at least one electrical end connector <NUM> can be arranged in the one or more of the first <NUM> and second <NUM> end panel grooves, e.g. being inserted into the one or more of the first <NUM> and second <NUM> end panel grooves. The first <NUM> and second <NUM> end panel grooves are facing the first <NUM> and second <NUM> end sides, respectively, i.e. the opening/aperture of the grooves are directed towards the first <NUM> and second <NUM> end sides, respectively. The first <NUM> and second <NUM> end panel grooves may further be arranged adjacent to the heat providing layer <NUM> such that the heat providing layer <NUM> is partly exposed within or is coupled to the inside of the first <NUM> and second <NUM> end panel grooves. In embodiments, an upper wall of first <NUM> and second <NUM> end panel grooves may at least partly include/expose a part of the heat providing layer <NUM>, as shown in e.g. <FIG> and <FIG>. The part of the heat providing layer <NUM> included in the upper wall of first <NUM> and second <NUM> end panel grooves may be partly conductive, e.g. may include first <NUM> and second <NUM> electrically conducting parts/sections of the heat providing layer <NUM> as shown in <FIG>. In embodiments, the first <NUM> and second <NUM> end panel grooves may instead at least partly include a coupling to the heat providing layer <NUM>, as is explained in detail below.

When the at least one electrical end connector <NUM> is arranged in the one or more of the first <NUM> and second <NUM> end panel grooves, the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> is arranged to protrude at least partly from the one or more of the first <NUM> and second <NUM> end panel grooves in its relaxed state. When the panel <NUM> is being coupled to an adjacent panel <NUM>, <NUM>, the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> is arranged to be pressed into at least one of the first <NUM> and second <NUM> end panel grooves by at least one of first <NUM>' and second <NUM>' end panel coupling means of the adjacent panel <NUM>, <NUM>. Furthermore, the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> is arranged to relax, i.e. to at least partly return towards its relaxed/non-tensioned/normal state/form, into at least one of the first <NUM>' and second <NUM>' end panel grooves of the adjacent panel <NUM>, <NUM> when the panel <NUM> is coupled to the adjacent panel <NUM>, <NUM>. In other words, when the panel <NUM> is coupled to the adjacent panel <NUM>, <NUM>, the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> is arranged to be snapped into at least one of the first <NUM>' and second <NUM>' end panel grooves of the adjacent panel <NUM>, <NUM>, thereby mechanically coupling/locking and electrically coupling the panel <NUM> to the adjacent panel <NUM>, <NUM>. The mechanically coupling/locking of the panel <NUM> to the adjacent panel <NUM>, <NUM> using the electrical end connector <NUM> will now be further described with reference to <FIG>.

<FIG> schematically illustrates the coupling of the panel <NUM> to the adjacent panel <NUM> according to an embodiment of the invention. <FIG> illustrates the panel <NUM> in an initial stage before the panel <NUM> is coupled to the adjacent panel <NUM>. In the initial stage, the electrical end connector <NUM> is arranged in the first end panel groove <NUM> of the first end panel coupling means <NUM> of the panel <NUM>. The electrical end connector <NUM> may be fixed, e.g. by being pre-fixed, to the panel <NUM> by insertion into the first end panel groove <NUM> of the first end panel coupling means <NUM> of the panel <NUM>. The electrical end connector <NUM> is then in its relaxed/non-tensioned/normal/initial state/form, and hence the at least partly resilient portion <NUM> of the electrical end connector <NUM> protrudes at least partly from the first end panel groove <NUM>, as shown in <FIG>. The panel <NUM> is thereby ready to be coupled to the adjacent panel <NUM>.

<FIG> illustrates an intermediate stage of the coupling of the panel <NUM> to the adjacent panel <NUM>, e.g. when the panel <NUM> has already been mounted on the floor/wall/ceiling and it is time for the adjacent panel <NUM> to be mounted on the floor/wall/ceiling by coupling it to the panel <NUM>. During the coupling, the adjacent panel <NUM> is first tilted and then pressed down towards the panel <NUM> to couple the first end panel coupling means <NUM> of the panel <NUM> to the second end coupling means <NUM>' of the adjacent panel <NUM>. In the embodiment shown in <FIG>, the adjacent panel <NUM> is tilted such that the second longitudinal side <NUM>' of the adjacent panel <NUM> is level with the second longitudinal side <NUM> of the panel <NUM>, while the first longitudinal side <NUM>' of the adjacent panel <NUM> is higher than the first longitudinal side <NUM> of the panel <NUM>. When the first longitudinal side <NUM>' of the adjacent panel <NUM> is being pressed down towards the first longitudinal side <NUM> of the panel <NUM>, the at least partly resilient portion <NUM> of the electrical end connector <NUM> is pressed into the first end panel groove <NUM> of the panel <NUM> by the second end panel coupling means <NUM>' of the adjacent panel <NUM>. The dimensions of the at least partly resilient portion <NUM> of the electrical end connector <NUM> and the first end panel groove <NUM> of the panel <NUM> may be selected/chosen such that the whole at least partly resilient portion <NUM> of the electrical end connector <NUM> can be pressed into the first end panel groove <NUM> of the panel <NUM>, allowing the adjacent panel <NUM> to be arranged level and in contact with the panel <NUM>, i.e. aligned with the panel <NUM>. Further details related to the shape and dimensions of the at least partly resilient portion <NUM> of the electrical end connector <NUM> and the first <NUM> and second <NUM> end panel grooves of the panel <NUM> will be described below with reference to <FIG>.

<FIG> illustrates a final stage of the coupling of the panel <NUM> to the adjacent panel <NUM>. In <FIG>, the coupling is completed and the panel <NUM> is hence mechanically and electrically coupled to the adjacent panel <NUM>. The adjacent panel <NUM> has been pressed down such that it is level/aligned with the panel <NUM> and the first end panel coupling means <NUM> of the panel <NUM> has been coupled to the second end coupling means <NUM>' of the adjacent panel <NUM>. Furthermore, the at least partly resilient portion <NUM> of the electrical end connector <NUM> has returned at least partly towards its relaxed/non-tensioned/normal/initial state/form by relaxing into the second end panel groove <NUM>' of the adjacent panel <NUM>, as illustrated in <FIG>. In other words, the at least partly resilient portion <NUM> of the electrical end connector <NUM> has been snapped into the second end panel groove <NUM>' of the adjacent panel <NUM>, thereby mechanically coupling/locking the panel <NUM> to the adjacent panel <NUM> and electrically coupling the panel <NUM> to the adjacent panel <NUM>.

As described above and below, the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> is at least partly electrically conductive, i.e. includes one or more conductive sections, which provides an electrical connection between the panel <NUM> and the adjacent panel <NUM>, i.e. between the heat providing layers <NUM>, <NUM>' of the panel <NUM> and the adjacent panel <NUM>. In embodiments, the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> provides the electrical connection between the heat providing layers <NUM>, <NUM>' of the panel <NUM> and the adjacent panel <NUM> using electrically conducting tongues. Thus, the one or more conductive sections then include one or more electrically conductive tongues, respectively. The tongues are in this embodiment arranged to be in electrical contact with the heat providing layers <NUM>, <NUM>' of the panel <NUM> and of the adjacent panel <NUM>, respectively.

<FIG> illustrates the electrical end connector <NUM> according to such an embodiment. In <FIG>, the at least partly resilient portion <NUM> of the electrical end connector <NUM> includes a first <NUM> and a second <NUM> electrically conducting tongue. The first <NUM> and second <NUM> electrically conducting tongues may be attached to the at least partly resilient portion <NUM> e.g. by a nail, by soldering and/or by an adhesive. Furthermore, the first <NUM> and second <NUM> electrically conducting tongues may be at least partly wave-formed. However, the first <NUM> and second <NUM> electrically conducting tongues may have other shapes that promote and/or provide electrical contact between the heat providing layers <NUM>, <NUM>'of the panel <NUM> and the adjacent panel <NUM>, without deviating from the scope of the invention.

The first <NUM> and second <NUM> electrically conducting tongues of the at least partly resilient portion <NUM> are arranged to be in electrical contact with the heat providing layer <NUM> of the panel <NUM> and with a corresponding heat providing layer <NUM>' of the adjacent panel <NUM>, <NUM> being coupled to the panel <NUM>. When the first <NUM> and second <NUM> electrically conducting tongues are wave-formed, the first <NUM> and second <NUM> electrically conducting tongues may each comprise a first wave and a second wave, as illustrated in <FIG>. In this case, the first wave of the first <NUM> and second <NUM> electrically conducting tongues, respectively, may be in electrical contact with the heat providing layer <NUM> of the panel <NUM>, while the second wave of the first <NUM> and second <NUM> electrically conducting tongues, respectively, may be in electrical contact with the corresponding heat providing layer <NUM>' of the adjacent panel <NUM>, <NUM> being coupled to the panel <NUM>. By using a wave-form, a pressure can be created between the heat providing layers <NUM>, <NUM>' and the first <NUM> and second <NUM> electrically conducting tongues which ensure a solid electrical connection.

According to embodiments of the invention, the heat providing layer <NUM> of the panel <NUM> includes first <NUM> and second <NUM> electrically conducting parts/sections, while the heat providing layer <NUM>' of the adjacent panel <NUM>, <NUM> includes corresponding first <NUM>' and second <NUM>' electrically conducting parts/sections, as illustrated in <FIG>. The first <NUM> and second <NUM> electrically conducting parts of the heat providing layer <NUM> may be adjacent to at least one of the first <NUM> and second <NUM> end panel grooves. The first <NUM> and second <NUM> electrically conducting parts may be located in an upper wall of at least one of the first <NUM> and second <NUM> end panel grooves and facing down into the space created by the first <NUM> and second <NUM> end panel grooves. In this way, the first <NUM> and second <NUM> electrically conducting parts are arranged to be in contact with the electrical end connector <NUM> when the electrical end connector <NUM> is arranged in the at least one of the first <NUM> and second <NUM> end panel grooves. In embodiments, the first <NUM> and second <NUM> electrically conducting tongues of the at least partly resilient portion <NUM> are arranged to be in electrical contact with the first <NUM> and second <NUM> electrically conducting parts, respectively, of the heat providing layer <NUM> of the panel <NUM> and with corresponding first <NUM>' and second <NUM>' electrically conducting parts, respectively, of a corresponding heat providing layer <NUM>' of an adjacent panel <NUM>, <NUM> being coupled to the panel <NUM>.

<FIG> show views of the electrical end connector <NUM> according to an embodiment where electrically conducting tongues are used to provide the electrical connection. However, according to some embodiments, the electrical connection may instead be provided by the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> being made partly of an electrically conducting material, e.g. including one or more sections of a suitable metal. The at least partly resilient portion <NUM> may e.g. comprise two parts/sections of an electrically conducting material separated by a non-electrically conducting material. In this case, the electrical connection between the panel <NUM> and the adjacent panel <NUM>, <NUM>, i.e. between the heat providing layers <NUM>, <NUM>' of the panel <NUM> and the adjacent panel <NUM>, <NUM>, is provided through the two conductive parts/sections of the at least partly resilient portion <NUM> of the electrical end connector <NUM>.

<FIG> and <FIG> show the dimensions of the at least partly resilient portion <NUM> of the electrical end connector <NUM> and the first <NUM> and second <NUM> end panel grooves of the panel <NUM> according to an embodiment of the invention. The dimensions of the at least partly resilient portion <NUM> and the first <NUM> and second <NUM> end panel grooves may be selected such that a solid electrical connection is achieved between the conductive parts/sections of the at least partly resilient portion <NUM> of the electrical end connector <NUM> and the conductive parts/sections of the heat providing layer <NUM>.

The first <NUM> and second <NUM> end panel grooves have a height Hend_groove essentially or approximately equal to a height Hend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM>; Hend_groove = Hend_con or Hend_groove ≈ Hend_con. Thus, the at least partly resilient portion <NUM> of the electrical end connector <NUM> is movable within the end panel grooves <NUM>, <NUM> with limited play, e.g. essentially without play, thereby providing a solid mechanical coupling/locking and electrical coupling. Thereby, when the electrical end connector <NUM> is arranged in at least one of the first <NUM> and second <NUM> end panel grooves, the conductive parts/sections of the at least partly resilient portion <NUM> of the electrical end connector <NUM> will be in contact with the heat providing layer <NUM> of the panel <NUM> exposed to the inside of the first <NUM> and second <NUM> end panel grooves. Hence, for the electrical end connector <NUM> shown in <FIG>, the first <NUM> and second <NUM> electrically conducting tongues of the at least partly resilient portion <NUM> of the electrical end connector <NUM> will press up against the heat providing layer <NUM> of the panel <NUM> constituting an upper wall of at least one of the first <NUM> and second <NUM> end panel grooves, when the electrical end connector <NUM> is arranged in at least one of the first <NUM> and second <NUM> end panel grooves of the panel <NUM>. The height Hend_con of the at least partly resilient portion <NUM> may in embodiments vary over the length of the at least partly resilient portion <NUM>. The height Hend_groove of the first <NUM> and second <NUM> end panel grooves would in this case correspond the height Hend_con of the at least partly resilient portion <NUM> at the location of the conductive parts/sections of the at least partly resilient portion <NUM>.

Furthermore, at least one of the first <NUM> and second <NUM> end panel grooves may have a first depth Dend_groove1 essentially equal to or larger than a width Wend_con of the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM>; Dend_groove1 ≥ Wend_con; while at least one of the first <NUM> and second <NUM> end panel grooves may have a second depth Dend_groove2 smaller than the width Wend_con of the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM>, i.e. Dend_groove2 < Wend_con. If the width Wend_con of the at least partly resilient portion <NUM> varies over the length of the at least partly resilient portion <NUM>, the first depth Dend_groove1 may be selected based on the maximum width Wend_con of the at least partly resilient portion <NUM> and the second depth Dend_groove2 may be selected based on the maximum width Wend_con and/or the width Wend_con of the at least partly resilient portion <NUM> at the location of the conductive parts/sections of the at least partly resilient portion <NUM>.

An end panel groove <NUM>, <NUM> having the first depth Dend_groove1 allows the full width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM> to be received in the end panel groove <NUM>, <NUM>. Thereby, during the coupling of the panel <NUM> to the adjacent panel <NUM>, <NUM> the at least partly resilient portion <NUM> of the electrical end connector <NUM> can be fully pressed into the end panel groove <NUM>, <NUM> having the first depth Dend_groove1. Hence, an end panel groove <NUM>, <NUM> having the first depth Dend_groove1 is suitable to be fitted with the electrical end connector <NUM> in its relaxed state before coupling the panel <NUM> to the adjacent panel <NUM>, <NUM>.

On the other hand, an end panel groove <NUM>, <NUM> having the second depth Dend_groove2 can not receive the full width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM>. Therefore, at least a portion of the at least partly resilient portion <NUM> of the electrical end connector <NUM> will protrude from the end panel groove <NUM>, <NUM> with the second depth Dend_groove2. Hence, an end panel groove <NUM>, <NUM> having the second depth Dend_groove2 is suitable to receive the corresponding at least partly resilient portion <NUM>' of the electrical end connector <NUM>' of the adjacent panel <NUM>, <NUM> when coupling the panel <NUM> to the adjacent panel <NUM>, <NUM>.

In the embodiment shown in <FIG>, the first end panel groove <NUM> has the first depth Dend_groove1, which in this embodiment is at least equal to the width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM>. Furthermore, the second end panel groove <NUM> has the second depth Dend_groove2, which in this embodiment is essentially or approximately half that of the width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM>. The first end panel groove <NUM> is thereby adapted to receive the electrical end connector <NUM> in its relaxed state, as shown e.g. in <FIG>. The first end panel groove <NUM> is further adapted to allow the whole at least partly resilient portion <NUM> of the electrical end connector <NUM> to be pressed into the first end panel groove <NUM> when the panel <NUM> is being coupled to the adjacent panel <NUM>. The second end panel groove <NUM> is on the other hand adapted to allow the corresponding at least partly resilient portion <NUM>' of the electrical end connector <NUM>' of the adjacent panel <NUM> to be snapped into it when the panel <NUM> is being coupled to the adjacent panel <NUM>. When the at least partly resilient portion <NUM>' of the electrical end connector <NUM>' of the adjacent panel <NUM> has been snapped into the second end panel groove <NUM>, the second end panel groove <NUM> has received essentially or approximately half the width Wend_con of the at least partly resilient portion <NUM>' of the electrical end connector <NUM>', while essentially or approximately half the width Wend_con of the at least partly resilient portion <NUM>' of the electrical end connector <NUM>' remains in the corresponding first end panel groove <NUM>' of the adjacent panel <NUM>. Thereby, the at least partly resilient portion <NUM>' of the electrical end connector <NUM>' is simultaneously connected to the heat providing layer <NUM> of the panel <NUM> and the heat providing layer <NUM>' of the adjacent panel <NUM>.

<FIG> shows the position of the electrical end connector <NUM> when the panel <NUM> has been coupled to the adjacent panel <NUM>. In the embodiment shown in <FIG>, the first end panel groove <NUM> of the panel <NUM> has the first depth Dend_groove1, which in this embodiment is approximately equal to the width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM>. Furthermore, the second end panel groove <NUM>' of the adjacent panel <NUM> has the second depth Dend_groove2, which in this embodiment is approximately half the width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM>. As shown in <FIG>, when the at least partly resilient portion <NUM> of the electrical end connector <NUM> of the panel <NUM> has been snapped into the second end panel groove <NUM>' of the adjacent panel <NUM>, approximately half the width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM> is in the second end panel groove <NUM>', while approximately half the width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM> is in the first end panel groove <NUM> of the panel <NUM>. Thereby, the first <NUM> and second <NUM> electrically conducting tongues of the at least partly resilient portion <NUM> of the electrical end connector <NUM> are simultaneously connected to the first <NUM> and second <NUM> electrically conducting parts of the heat providing layer <NUM> of the panel <NUM> and the first <NUM>' and second <NUM>' electrically conducting parts of the heat providing layer <NUM>' of the adjacent panel <NUM>. Thereby, providing an electrical connection between the heat providing layer <NUM> of the panel <NUM> and the heat providing layer <NUM>' of the adjacent panel <NUM>.

<FIG> shows the electrical end connector <NUM> according to an embodiment of the invention. In the embodiment shown in <FIG>, the at least partly resilient portion <NUM> of the electrical end connector <NUM> includes a first <NUM> and a second <NUM> portions being resiliently connected to each other. The first <NUM> and second <NUM> portions of the at least partly resilient portion <NUM> may be resiliently connected to each other by means of at least one in the group of a spring joint, and a resilient member. Alternatively or in addition, at least one of the first <NUM> and second <NUM> portions of the at least partly resilient portion <NUM> may include a resilient material such that the at least one of the first <NUM> and second <NUM> portions are in itself resilient/flexible.

In embodiments where the at least partly resilient portion <NUM> of the electrical end connector <NUM> includes the first <NUM> and second <NUM> portions, the first <NUM> and second <NUM> portions of the at least partly resilient portion <NUM> may include first <NUM> and second <NUM> electrically conducting tongues, respectively, as shown in <FIG>.

In embodiments, the at least partly resilient portion <NUM> of the electrical end connector <NUM> may instead be a single part (not shown). In this case, the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> may include a resilient material, i.e. the at least partly resilient portion <NUM> of the electrical end connector <NUM> is in itself resilient/flexible.

It is the resilience of the at least partly resilient portion <NUM> of the electrical end connector <NUM> that allows the electrical end connector <NUM> to be used to mechanically couple/lock the panel <NUM> to the adjacent panel <NUM>, <NUM>, as well as provide the electrical connection between the panel <NUM> and the adjacent panel <NUM>, <NUM>. The shape and resilience of the at least partly resilient portion <NUM> of the electrical end connector <NUM> may be selected such that a smooth mechanical coupling/locking is achieved. For example, by arranging the at least partly resilient portion <NUM> towards one of the ends of the electrical end connector <NUM>, the force required to press down the adjacent panel <NUM>, <NUM> towards that end during the coupling to the panel <NUM> can be reduced. Thereby, the risk of breaking the electrical end connector <NUM>, the panel <NUM>, and/or the adjacent panel <NUM>, <NUM> during the coupling is reduced. Hence, in embodiments the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> is arranged to be located closer to the first end portion <NUM> than to the second end portion <NUM>, or vice versa. <FIG> shows an embodiment where the at least partly resilient portion <NUM> of the electrical end connector <NUM> is located closer to the first end portion <NUM> than to the second end portion <NUM>. In <FIG>, the electrical end connector has a length L and a most protruding part <NUM> of the at least partly resilient portion <NUM> of the electrical end connector <NUM> is arranged to be located a first length L1 from the first end portion <NUM>. The length L1 of the non-limiting example in <FIG> is approximately <NUM>% of the length L, i.e. the ratio between the first length L1 and the length L is approximately <NUM>; L1/L ≈ <NUM>.

In embodiments, the most protruding part <NUM> of the at least partly resilient portion <NUM> of the electrical end connector <NUM> may instead be located closer to or further away from the first end portion <NUM>. Hence, the length L of the electrical end connector <NUM> and the first length L1 between the most protruding part <NUM> and the first end portion <NUM> may be selected such that the ratio between the first length L1 and the length L is at least one interval in the group (or an interval based on the limiting values in the group) of: <MAT> <MAT> <MAT>.

The location of the most protruding part <NUM> of the at least partly resilient portion <NUM> of the electrical end connector <NUM> along the electrical end connector <NUM> may be selected based on factors such as e.g. the strength of at least one of the first <NUM> and second <NUM> end panel coupling means, a desired strength of the mechanical coupling/locking etc. For example, if the first <NUM> and second <NUM> end panel coupling means are made of a strong material, e.g. solid wood, the most protruding part <NUM> of the at least partly resilient portion <NUM> of the electrical end connector <NUM> may be located in the middle or close to the middle of the electrical end connector <NUM>. Thereby, the electrical end connector <NUM> can provide a strong mechanical coupling/locking. On the other hand, if the first <NUM> and second <NUM> end panel coupling means are made of a less strong material, e.g. wood fiber board, the most protruding part <NUM> of the at least partly resilient portion <NUM> of the electrical end connector <NUM> may be located closer to one end of the electrical end connector <NUM>, e.g. <NUM>-<NUM> of the length L from the end of the electrical end connector <NUM>. Thereby, reducing the force required for the mechanical coupling/locking and hence the risk of breaking the first <NUM> and second <NUM> end panel coupling means and/or the electrical end connector <NUM> during the mechanical coupling/locking.

Furthermore, the shape and resilience of the at least partly resilient portion <NUM> of the electrical end connector <NUM> may be selected such that in its relaxed state the at least partly resilient portion <NUM> is arranged to protrude at least partly more than its width, i.e. more than the width Wend_con of the at least partly resilient portion <NUM> of the electrical end connector <NUM>, as shown e.g. in <FIG>. In the embodiment shown in <FIG>, the at least partly resilient portion <NUM> of the at least partly resilient portion <NUM> protrudes more than the width Wend_con of the at least partly resilient portion <NUM> at the most protruding part <NUM> of the at least partly resilient portion <NUM>. The at least partly resilient portion <NUM> of the at least partly resilient portion <NUM> may e.g. protrude between <NUM> and <NUM> times the width Wend_con of the at least partly resilient portion <NUM>. This ensures a strong enough spring force such that the electrical end connector <NUM> can be used to mechanically couple the panel <NUM> to the adjacent panel <NUM>, <NUM>.

<FIG> illustrate an embodiment of the present invention, in which the panel <NUM> includes at least one sandwich/insulating core <NUM> included in the base layer <NUM>. The at least one sandwich/insulating core <NUM> may have heat insulating properties, preventing that created heat is transported in the wrong direction, i.e. away from the space to be heated. For example, a temperature increase of e.g. <NUM> for a panel without insulation could result in a temperature increase of e.g. <NUM>-<NUM> for the same panel with at least one sandwich/insulating core <NUM> added to the base layer <NUM>. The at least one sandwich/insulating core <NUM> may also have sound/noise absorbing properties, which then efficiently reduces the noise of e.g. high heels being walked across the floor.

The sandwich/insulating core <NUM> may e.g. include polyurethane, for example in form of a polyurethane foam being injected at and/or after assembly of the layers of the panel <NUM>.

<FIG> illustrate some embodiments of the present invention, in which the panel <NUM> includes at least one sandwich/insulating core <NUM> included in the base layer <NUM>. The at least one sandwich/insulating core <NUM> may here e.g. include pyramid formed support elements E that may, by the side surfaces A, B of the pyramid forms, provide supportive force/pressure from the pyramid formed support elements E on the corresponding pyramid formed parts D of the base layer <NUM> of the panel <NUM>, such that they may carry heavier loads. The pyramid formed support elements E may have their base side facing away from the covering layer <NUM>, and the pointed side towards the covering layer <NUM>. As mentioned above, the at least one sandwich/insulating core <NUM> may have heat and/or sound/noise insulating properties. Thus, the pyramid shaped support elements provide optimal insulation in combination with an optimal carrying capacity for the panel <NUM>.

<FIG> illustrate an embodiment, for which load/weight carrying element <NUM> are arranged between the sandwich/insulating core pyramid forms <NUM> in the base layer <NUM> material, which may be e.g. wood or some other material suitable for carrying weight. The load carrying element <NUM> may for example have a circular form, e.g. may be essentially screw/bolt-formed with a wider circular head part and a thinner circular pointed part, with the wider part directed towards the covering layer <NUM>. The load carrying element <NUM> may be of essentially any load carrying material, such as e.g. metal or plastic. The circular head part of the load carrying element <NUM> is arranged for carrying weight/load originating from the covering layer <NUM>, such that the bottom regions of the pyramid formed parts D of the base layer <NUM> may be less strong, i.e. do not have to be strong enough to itself take up the whole carrying weight/load. Thus, the weight/load originating from the covering layer is here at least partly carried by the load carrying elements <NUM>.

The load carrying elements <NUM> may be casted/moulded together with base layer <NUM> material in order to improve the load carrying capabilities of the panel <NUM>, i.e. to improve the load/weight carrying capabilities of the base layer <NUM> material. Hereby, a less stable and more porous material may be used for the rest of the base layer <NUM> material, which lowers the production costs.

According to an aspect of the present invention, an electrical end connector <NUM> is presented. The electrical end connector <NUM> and its embodiments are described in this document, and is illustrated e.g. in <FIG> and <FIG>. The electrical end connector <NUM> is insertable into one or more of the first <NUM> and second <NUM> end panel coupling means of the herein described panel <NUM>, according to the herein described embodiments.

As previously described and shown in e.g. <FIG>, the electrical end connector <NUM> includes the first <NUM> and second <NUM> end portions and the at least partly resilient portion <NUM> located between the first <NUM> and second <NUM> end portions. The at least partly resilient portion <NUM> being at least partly electrically conductive and at least partly protruding from the one or more of the first <NUM> and second <NUM> end panel coupling means when being inserted into one or more of the first <NUM> and second <NUM> end panel coupling means. The electrical end connector <NUM> thereby provides an electrical connection between the heat providing layer <NUM> of the panel <NUM> and a corresponding heat providing layer <NUM>' of at least one adjacent panel <NUM>, <NUM> coupled to the panel <NUM>. According to an embodiment, the at least partly resilient portion <NUM> of the electrical end connector <NUM> may be arched, or may be arranged like a triangle with an angle between the first <NUM> and second <NUM> portions, such that the at least partly resilient portion <NUM> protrude between <NUM> and <NUM> times the width Wend_con of the at least partly resilient portion <NUM> from the bottom/base of the arch/triangle to the top of the arch/triangle. This ensures a strong spring force and a solid mechanical and electrical coupling of the panel <NUM> to an adjacent panel <NUM>, <NUM>.

As described above with reference to <FIG>, when the panel <NUM> and the adjacent panel <NUM> are mechanically coupled together, the at least partly resilient portion <NUM> of the electrical end connector <NUM> is, according to various embodiments, inserted/received in the end panel grooves <NUM>, <NUM>' of the panel <NUM> and the adjacent panel <NUM>, whereby the at least partly resilient portion <NUM> provides the electrical connection between the heat providing layers <NUM>, <NUM>' of the panel <NUM> and of the adjacent panel <NUM>.

According to embodiments, the electrical end connector <NUM> also provides a mechanical coupling to at least one adjacent panel <NUM>, <NUM>, e.g. by snap locking.

As mentioned above, and also being illustrated e.g. in <FIG>, the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM> may, according to an embodiment, include first <NUM> and second <NUM> electrically conducting tongues, respectively. The first <NUM> and second <NUM> electrically conducting tongues are arranged for being in electrical contact with the heat providing layer <NUM> of the panel <NUM> and with a corresponding heat providing layer <NUM>' of an adjacent panel <NUM>, <NUM>, when the panel <NUM> is coupled to the adjacent panel <NUM>, <NUM>.

According to an embodiment, the first <NUM> and second <NUM> electrically conducting tongues have a form being suitable for creating a solid electrical contact with the heat providing layers <NUM>, <NUM>'. The first <NUM> and second <NUM> electrically conducting tongues may e.g. be at least partly wave-formed, with the peaks of the wave form pointing towards the heat providing layers <NUM>, <NUM>'.

The electric energy being conveyed to the heat providing layer <NUM>, <NUM>' by the at least partly resilient portion <NUM> may have a voltage in the interval of <NUM> Volts - <NUM> Volts, or in the interval of <NUM> Volts - <NUM> Volts, or in the interval of <NUM> Volts - <NUM> Volts, or in the interval of <NUM> Volts - <NUM> Volts. The panel <NUM> according to the present invention may be supplied with such low voltages since the electrical contact between adjacent panels, and possibly also the heat providing layers, and therefore of the panel <NUM> itself, are very good, i.e. have low losses.

According to an example embodiment of the present invention, the electric energy being supplied to the heat providing layer <NUM> in order to create the heat has a voltage V of <NUM> Volts; V = <NUM> volt, which in many regions and/or countries may be handled by a layman, i.e. by a non-electrician.

According to another example embodiment of the present invention, the electric energy has a voltage V of <NUM> Volts; V = <NUM> volt, which in some regions and/or countries may be handled by a layman.

As described above, at least first <NUM> and second <NUM> longitudinal grooves may be arranged in the base layer <NUM> of the panel <NUM>, as shown in <FIG> and <FIG>. The first <NUM> and second <NUM> longitudinal grooves may extend from the first end side <NUM> to the second end side <NUM> and face the heat providing layer <NUM>. Furthermore, the at least first <NUM> and second <NUM> longitudinal grooves may be arranged in parallel with, and have at least a first <NUM> and a second <NUM> distances to, the first <NUM> and second <NUM> longitudinal sides, respectively. The panel <NUM> may, according to some embodiments of the present invention, include further longitudinal grooves, i.e. may in total include more than two longitudinal grooves.

The at least first <NUM> and second <NUM> longitudinal grooves may in embodiments be used to provide electrical connection between the panel <NUM> and an electrical energy providing arrangement <NUM>. In such embodiments, the panel <NUM> further comprises at least first <NUM> and second <NUM> electrical power supply end connectors arranged in the at least first <NUM> and second <NUM> longitudinal grooves, respectively, at the first end side <NUM> or the second end side <NUM>, the at least first <NUM> and second <NUM> electrical power supply end connectors being arranged to provide an electrical connection between the heat providing layer <NUM> of the panel <NUM> and an electrical energy providing arrangement <NUM>. The electrical energy providing arrangement <NUM> may be part of a heating system <NUM>, as will now be described with reference to <FIG>.

According to an aspect of the present invention, a heating system <NUM> is presented. The heating system <NUM>, is schematically illustrated in <FIG>, and includes at least one panel <NUM>, <NUM> as described above. The heating system further includes an electrical energy providing arrangement <NUM>, arranged e.g. at a mounting base <NUM> and/or facing the base layer <NUM> adjacent to at least one of the first <NUM> and the second <NUM> end sides of the at least one panel <NUM>, <NUM>. The electrical energy providing arrangement <NUM> supplies the electric energy to at least one first <NUM> and at least one second <NUM> electrical power supply end connectors of the panel <NUM>. In <FIG>, only two panels <NUM>, <NUM> are shown for simplicity. As is clear for a skilled person, many more panels may be included in the heating system <NUM>. Also, each one of the panels <NUM>, <NUM> in <FIG> may represent a row of panels. It should be noted that the electrical energy providing arrangement <NUM> described in this document may be used for supplying electrical energy to essentially any electrically heated panel, i.e. not only to the herein described panel <NUM>.

According to the embodiment shown in <FIG>, the electrical energy is provided by first and second polarities P1, P2 being supplied to the first <NUM> and second <NUM> electrical power supply end connectors of the first end side <NUM> of the panel <NUM>, or to a corresponding first end side <NUM>' of an adjacent panel <NUM> coupled directly or indirectly to the first end side <NUM> of the panel <NUM>. Thus, both the first and second polarities P1, P2 are connected to a first end side <NUM> of a first panel <NUM>, <NUM> in each row of panels being coupled together at their end sides <NUM>, <NUM>. The first and second polarities P1, P2 are then electrically connected to further panels in each row of panels, laid as illustrated in <FIG>, such that all panels of the whole floor/wall/ceiling are electrified. Hereby, the whole area covered by the panels is heated. Since the voltage used in <FIG> is rather low, e.g. <NUM> Volts, both of the first and second polarities P1, P2 may be supplied to the same end side <NUM> of the panel. This is possible since the risk for a dangerous electric shock of a person installing the panels is essentially non-existing at these low voltages.

According to another embodiment of the present invention, the electric energy has a voltage of <NUM> Volts; V = <NUM> Volts; which in some regions and/or countries may be handled by a layman, i.e. by a non-electrician. A heating system <NUM> is schematically illustrated in <FIG>, which includes at least one panel <NUM>, <NUM>, <NUM> as described above. The heating system further includes an electrical energy providing arrangement <NUM>, arranged e.g. at a mounting base <NUM> and/or facing the base layer <NUM>, on two opposite sides of a floor, wall or ceiling, and adjacent to at both the first <NUM> and the second <NUM> end sides of the at least one panel <NUM>, <NUM>, <NUM>. It should be noted that the electrical energy providing arrangement <NUM> described in this document may be used for supplying electrical energy to essentially any electrically heated panel, i.e. not only to the herein described panel <NUM>.

The electrical energy providing arrangement <NUM> may include contact means <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, each one being arranged for providing one polarity P1, P2 to the panel <NUM>, <NUM>, <NUM> by use of a contact protrusion <NUM> and/or first <NUM> and second <NUM> electrical power supply end connectors. The contact means <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and/or the panels <NUM>, <NUM>, <NUM> may also include a stability protrusion <NUM>.

When the contact means <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are assembled with, i.e. are inserted into, the panels <NUM>, <NUM>, <NUM>, the electrical energy is provided to the panels <NUM>, <NUM>, <NUM> by the contact protrusions <NUM>, and the panels <NUM>, <NUM>, <NUM> are held in place by the stability protrusions <NUM>. Also, the electrical energy, i.e. the voltage creating the heat in the panels <NUM>, <NUM>, <NUM>, is encapsulated within the panels <NUM>, <NUM>, <NUM> by the contact means <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The risk for getting an electric shock is therefore minimized for the heating system <NUM> illustrated in <FIG>, partly due to the encapsulated electrical energy, and partly because the two polarities P1, P2 are provided to opposite sides of a floor, wall or ceiling being covered by the panels, and are therefore difficult, often impossible, for a person to come in physical contact with both of P1 and P2 at the same time.

Also, the voltage drop over the heat providing layer <NUM> is approximately reduced by <NUM> % when the two polarities P1, P2 are provided to opposite sides of a floor.

According to an embodiment of the present invention, schematically illustrated in <FIG>, the electrical energy is thus provided to the panel <NUM> by the first polarity P1 being supplied to the first <NUM> or second <NUM> electrical power supply end connectors of the first end side <NUM> of a panel <NUM>. The second polarity P2 is then supplied to the first <NUM> or second <NUM> electrical power supply end connectors of the second end side <NUM> of the panel. Thus, the first polarity P1 is supplied to one end side <NUM> of the panel <NUM>, and the second polarity P2 is supplied to the opposite end side <NUM> of the panel <NUM>.

Also, the second polarity P2 may be supplied to the first <NUM> or second <NUM> electrical power supply end connectors of a corresponding first end side <NUM>' of an adjacent panel <NUM> coupled directly or indirectly to the first end side <NUM> of the panel <NUM>, as illustrated in <FIG>. Also, the second polarity P2 may be supplied to the first <NUM> or second <NUM> electrical power supply end connectors of a corresponding second end side <NUM>' of an adjacent panel <NUM> coupled directly or indirectly to the second end side <NUM> of the panel <NUM>.

The electrical energy providing arrangement <NUM> thus supplies the electric energy to the first <NUM> and second <NUM> electrical power supply end connectors on two opposite end sides of the at least one panel <NUM>, <NUM>, <NUM>. In <FIG>, only three panels <NUM>, <NUM>, <NUM> are shown for simplicity. As is clear for a skilled person, however, many more panels may be included in the heating system <NUM>. Also, each one of the panels <NUM>, <NUM>, <NUM> in <FIG> may represent a row of panels.

<FIG> schematically illustrates a complete heating system. As illustrated in <FIG>, and mentioned above, first <NUM> and second <NUM> electrical power supply end connectors, may be used on one end side <NUM> of the panel, if this end side is the end side starting a row of panels, i.e. is the end side facing a wall, socket or the like from which the electrical power is provided to the row of panels. These first <NUM> and second <NUM> electrical power supply end connectors may be essentially any kind of connector/terminal creating a solid electrical connection, such as e.g. a connector being at least partly resilient and slightly tilted vertically, for example in an upward direction, as illustrated in <FIG>, providing a connection force between the first <NUM> and second <NUM> electrical power supply end connectors and a contact means <NUM> of an electrical energy providing arrangement <NUM> including e.g. a mounting base <NUM> arranged for example along at least one wall on at least one side of a floor, wall or ceiling, and adjacent to the end side of the at least one panel <NUM>.

The at least one first contact means <NUM> may here e.g. be arranged as an electrically conducting contact strip, possibly in metal, being arranged horizontally in the electrical energy providing arrangement <NUM>, such that it provides for a contact surface for the slightly upwardly tilted first <NUM> and second <NUM> electrical power supply end connectors. Thus, a vertical contact force Fcon is created when the at least one panel <NUM> and the electrical energy providing arrangement <NUM>, e.g. in the form of a mounting base, are mounted together.

Also, the electrical energy providing arrangement <NUM>, e.g. included in the mounting base <NUM> described in this document may, as mentioned above, be used for supplying electrical energy to essentially any electrically heated panel, i.e. not only to the herein described panel <NUM>, and/or to any other electrical energy consuming device <NUM>, such as e.g. a wall or ceiling heating panel, a lamp or the like. The electrical energy providing arrangement <NUM> may for this reason include at least one second contact means <NUM>.

According to an embodiment, the at least one first contact means <NUM> may be provided with first polarity P1, and the at least one second contact means <NUM> may be provided with another second polarity P2.

Hereby, the electrical energy providing arrangement <NUM> may supply electrical energy to essentially any electrical device <NUM> driven by the voltage provided by the electrical energy providing arrangement <NUM>. For example, many kinds of lamps are driven by lower voltages, such as e.g. <NUM> Volt or <NUM> Volt, and may therefore be directly supplied with this voltage from the electrical energy providing arrangement <NUM>.

Also, the at least one first <NUM> and the at least one second <NUM> contact means of adjacent parts of the energy providing arrangement <NUM>, e.g. in the form of adjacent mounting base parts mounted together, may be electrically coupled by means of coupling means <NUM>, <NUM>, e.g. in form of sheet metal, that may possibly correspond in form and/or function to the herein described first <NUM> and second <NUM> electrical power supply end connectors.

In <FIG>, a heating system according to an embodiment is illustrated. The electrical energy providing arrangement <NUM> is here located underneath the panel <NUM>, i.e. facing the base layer <NUM> of the panel. The at least one first <NUM> and at least one second <NUM> electrical power supply end connectors are then bent around at least one of the first <NUM>, <NUM>' and the second <NUM>, <NUM>' end sides of the panel, and are arranged between the base layer <NUM> of the panel <NUM> and the electrical energy providing arrangement <NUM>. Hereby, the at least one first <NUM> and at least one second <NUM> electrical power supply end connectors are pressed against, and are thus in electrical contact with, at least one part of the electrical energy providing arrangement <NUM>. The electrical energy providing arrangement <NUM> may, according to an embodiment, include at least one adhesive tape comprising an electrically conducting element <NUM> facing the base layer <NUM> of the panel <NUM>. The adhesive tape may for example be pasted/arranged on a floor adjacent to a wall, and thus also adjacent to a panel end side <NUM>, in order to create contact with the at least one first <NUM> and at least one second <NUM> electrical power supply end connectors. On the rest of the floor, i.e. underneath the rest of the panels, a stepping layer <NUM>, being e.g. a thin foam and/or paper layer, may cover the floor.

According to an embodiment of the present invention, a method for installing the heating system <NUM> is presented When panels according to the present invention are to be assembled/laid to become e.g. a floor, the electrical energy providing arrangement <NUM>, <NUM> described above may first be arranged/mounted at a mounting base <NUM>, <NUM> and/or facing the base layer <NUM> on one or two sides of the room to be floored. For example, a lower voltage energy providing arrangement, providing e.g. <NUM> Volts may be arranged/mounted along one wall of a room and then provides both polarities P1, P2 of the voltage. A higher voltage energy providing arrangement, providing e.g. <NUM> Volts, may instead be arranged along two opposite sides of a room and then provides one polarity of the voltage from each opposite side of the room. Thus, the electrical energy is then available at one or two sides of the room.

A first panel <NUM> is then mechanically coupled to at least one second panel <NUM>, <NUM> by use of the electrical end connector <NUM> of the panel <NUM>, the first end panel coupling means <NUM> of the panel <NUM>, and the second end panel coupling means <NUM>' of the at least second panel <NUM>, <NUM>. Hereby, a row of two or more panels <NUM>, <NUM>, <NUM> is created. The last second panel <NUM> in such a row of panels may have to be cut such that the length of the row corresponds to the length of the room.

At the same time as the panels of the row are mechanically coupled, an electrical connection of the first panel <NUM> and the at least one second panel <NUM>, <NUM> is achieved by the at least one electrical end connector <NUM> of the first panel <NUM>. Thus, as the panels <NUM>, <NUM>, <NUM> are pressed together by the mechanical coupling means <NUM>, <NUM>, also the at least partly resilient portion <NUM> of the at least one electrical end connector <NUM>, of the panels <NUM>, <NUM>, <NUM> of the row are pressed into the first <NUM>, <NUM>' and second <NUM>, <NUM>' end panel grooves of the panels <NUM>, <NUM>, <NUM>, thereby causing an electrical connection of the heat providing layers <NUM>, <NUM>' of the panels <NUM>, <NUM>, <NUM>.

Then, the row of the first panel <NUM> and the at least one second panel <NUM>, <NUM> is supplied with electrical energy from the electrical energy providing arrangement <NUM>, <NUM>. According to an embodiment described above, which is useful e.g. for lower voltages, this is done by connecting both of the first <NUM> and second <NUM> electrical power supply end connectors of the first panel <NUM> to the electrical energy providing arrangement <NUM>, <NUM>, which then supplies both of the voltage polarities P1, P2 to the first end side <NUM> of the first panel <NUM>.

According to another embodiment described above, which is useful e.g. for higher voltages, the row of the first panel <NUM> and the at least one second panel <NUM>, <NUM> is supplied with electrical energy from the electrical energy providing arrangement <NUM>, <NUM> by connecting one of the first <NUM> and second <NUM> electrical power supply end connectors on the first end side <NUM> of the first panel <NUM> to the electrical energy providing arrangement <NUM>, <NUM>. The electrical energy providing arrangement <NUM>, <NUM> then provides the first side <NUM> of the first panel <NUM> of the row of panels with one polarity P1 of the electrical energy. Then, another one of the first <NUM> and second <NUM> electrical power supply end connectors on the second end side <NUM>' of the row, i.e. on the second side <NUM>' of the at least one second panel <NUM>, <NUM> is connected to the electrical energy providing arrangement <NUM>, <NUM>. The electrical energy providing arrangement <NUM>, <NUM> then provides the second side <NUM>' of the row with another polarity P2 of the electrical energy.

As mentioned above, to supply the row of panels <NUM>, <NUM>, <NUM> with one voltage polarity at each end of the row has an advantage in that the risk for a person laying the floor getting an electric shock by the electric energy being provided to the panels is considerably reduced. In order to get an electric shock, i.e. in order to come in contact with both polarities of the voltage, the person would have to reach across the entire room, along the whole length of the row of panels, which is not very likely. Thus, a higher voltage supply may be used with this embodiment of the invention.

In the following, some non-limiting examples descriptions of electrical properties and heating properties of a floor according to some of the herein described embodiments are presented.

A power consumption for the floor, P, is given as: <MAT> where U is the voltage applied on the heat providing layer, and I is the corresponding applied electrical current. The applied voltage U is given by the voltage Usupply provided by the power source minus a voltage drop ΔU between the power source and the heat providing layer, i.e.: <MAT>.

The current I flowing through the heat providing layer is given by ohm's law: <MAT> <MAT> where R is the resistance of the heat providing layer. The heat providing layer may be divided in heating modules/sections, where a multiple of modules/sections may be coupled in parallel. For one heat module/section the resistance is given by: <MAT> where the resistivity is a material parameter, e.g. for pure aluminum approximately <NUM> x <NUM>-<NUM> ohm m, Lc_heat is the length of the heating conductor (resistor), and Ac_heat is the cross section area of the heating conductor. The cross section area of the conductor Ac_heat is e.g. for a thin film given as: <MAT> where hc_heat is the height/thickness of the conductor (resistor), and w is the width of the conductor (resistor).

For example, for a heating module with a heating conductor length Lc_heat of <NUM>, a width of the heating conductor wc_heat of <NUM>,<NUM>, and a heating conductor film thickness of <NUM> micrometer, the resistance R is approximately <NUM> ohm for aluminum.

By combining equations <NUM> and <NUM> above, the power is given by: <MAT> i.e. the power increases with the square of the voltage, U, and is decreased with the inverse of the resistance R.

Because the resistivity is a material parameter, and the conducting heat film thickness is a physical parameter to be chosen, the power may be written as: <MAT>.

This means that for a chosen type of heat film, the wanted power P is most easily controlled by the voltage, and then by the length Lc_heat and width wc_heat of the heating conductor (resistor).

Since all electrical power P is converted to Joule heat Q, Pheat = dQ/dt, Pheat is equal to P. The time derivative of Joule heat Q, dQ/dt, which corresponds to a flow of thermal energy. The heat flow, dQ/dt, will flow in the negative direction of the temperature gradient.

The power supplied P will be transformed into heat flow, dQ/dt, which will flow downwards dQ/dtdown to the under lay structure by conduction dQ/dtcond, and upwards, dQ/dtup, by convection dQ/dtconv and radiation, dQ/dtrad, and for non-equilibrium to the rise of the temperature of the board/panel, dQ/dtboard.

For non-equilibrium the temperature of the board will be rised by dQ/dtboard.

Regarding the temporal behavior, the temperature derivative with regard to time of the board/panel is: <MAT> where dT/dt is hence proportional to dQ/dtboard, and obviously, the temperature will rise if dQ/dtboard is not zero.

If the board is well insulated from the underlay structure, dQ/dtcond will be small, and hence the temperature gradient in the board/panel will be small, therefore the temperature will approximately follow a first order differential equation. The time dependence of the board/panel will then be: <MAT> where Tinital is the temperature of the board/panel before the voltage V is applied, Tend is the final temperature, and tau is the characteristic time constant. <MAT> and for tau per area unit: <MAT> where cP is the specific heat capacity, Rth_tot is the total thermal resistance, density is the density of the board/panel, and d is the thickness of the board.

Regarding the heat flow dQ/dt and temperature rise of the board/panel, the temperature rise on the surface of the board/panel will be dependent on the power P, the ambient temperature Tamb, the thermal resistance downwards, Rth down (between the heat film and the ambient floor), the thermal resistance between the film and the ambient air Rth_up. Each layer of the board/panel has its own thermal resistance, i.e. for the board/panel substructure Rth_sub, any dampening layer under the board Rth_damp, the heating film substrate Rth_substrate, the covering layer, Rth_top, and for the interface between the covering layer and the ambient air, Rth_conv. The thermal resistances downwards add in series, and the thermal resistances upwards add also in a series. However, the total thermal resistance downwards and the total thermal resistance upwards is combined in a parallel manner to a total thermal resistance, Rth_tot: <MAT> <MAT> and <MAT>.

The temperature increase ΔTfilm in the heating film conductor (resistance) is given by: <MAT>.

The thermal resistance for a solid material Rth_cond due to thermal conduction is given as: <MAT>.

The thermal resistance convection is given as: <MAT>.

Some non-limiting examples of materials and thermal resistances are given in Table <NUM> below.

In the non-limiting example above, an equal heat flow, dQ/dt, in both directions, upwards and downwards, is provided, assuming that the underlay structure has the same temperature as the ambient floor.

The heat flow due to radiation dQ/dtheat is given by: <MAT> where epsilon is the emissivity factor and SB the Stefan-Boltzmann's constant.

For a surface in a cavity, the radiation has to consider the view factor F, so the heat flow due to radiation becomes: <MAT> where F ranges, i.e. is in the interval, from <NUM> to <NUM>.

The surface temperature of the panel is thus dependent on heat leakage to the underlay structure. For a well insulated floor panel, e.g. for <NUM> expanded polystyrene (PS), the temperature rise will be approximately <NUM> degrees for a power supply of 50W/m<NUM>, and <NUM> degrees for 25W/m<NUM>. If the insulation is poor, however, such as e.g. <NUM> PS, the temperature increase will be less, for example <NUM> degrees at <NUM> W/m<NUM>, according to experiments.

Claim 1:
A panel (<NUM>) comprising:
- a base layer (<NUM>);
- a heat providing layer (<NUM>) attached to said base layer (<NUM>), said heat being created by electric energy;
- a covering layer (<NUM>) attached to said heat providing layer (<NUM>);
- first (<NUM>) and second (<NUM>) opposite longitudinal sides including first (<NUM>) and second (<NUM>) longitudinal panel coupling means, respectively, arranged for coupling said panel (<NUM>) to adjacent panels (<NUM>, <NUM>,..., <NUM>);
- first (<NUM>) and second (<NUM>) opposite end sides including first (<NUM>) and second (<NUM>) end panel coupling means, respectively, arranged for coupling said panel (<NUM>) to adjacent panels (<NUM>,<NUM>,..., <NUM>); characterized by
- said first (<NUM>) and second (<NUM>) end panel coupling means including first (<NUM>) and second (<NUM>) end panel grooves, respectively, said first (<NUM>) and second (<NUM>) end panel grooves at least partly extending between said first (<NUM>) and second (<NUM>) opposite longitudinal sides, and
- at least one electrical end connector (<NUM>) arranged in one or more of said first (<NUM>) and second (<NUM>) end panel grooves of said first (<NUM>) and second (<NUM>) end panel coupling means, each of said at least one electrical end connector (<NUM>) including first (<NUM>) and second (<NUM>) end portions and an at least partly resilient portion (<NUM>) located between said first (<NUM>) and second (<NUM>) end portions, said at least partly resilient portion (<NUM>) at least partly including an electrically conductive material and at least partly protruding from said one or more of said first (<NUM>) and second (<NUM>) end panel coupling means, thereby providing an electrical connection between said heat providing layer (<NUM>) of said panel (<NUM>) and a corresponding heat providing layer (<NUM>') of at least one adjacent panel (<NUM>, <NUM>) coupled to said panel (<NUM>).