heating mat

Abstract

Heating mat (100) with a planar support (10) and at least one heating element (50, 52, 54, 56, 58) made of a wire-shaped or fibrous element (51, 53, 55, 57, 59) which is connected to the support (10), wherein the support (10) has at least one area (20, 21, 22) with the at least one heating element (50, 52, 54, 56, 58) in which the at least one heating element (50, 52, 54, 56, 58) has changes of direction along its length (30) on the support (10) that deviate from a straight course, characterized by the fact that the carrier (10): is designed to be reversibly stretchable with an elongation at break of at least 50% in at least one direction and the at least one heating element (50, 52, 54, 56, 58) is embroidered or sewn onto the carrier (10) and has at least two-dimensional elongation capability with an elongation reserve of at least 10% when the carrier (10) is stretched.

Description

State of the art

[0001] The invention relates to a heating mat with a planar support and at least one heating element connected to the support.

[0002] Heating mats are used, for example, for tempering and heating repair areas of fiber-reinforced composites or during the production of fiber-reinforced structures or composite components, hereinafter also referred to as laminates. The heating mats typically consist of a wire embedded in carrier materials such as silicone.

[0003] From DE 10 2017 116 931 A1, a repair device is known, comprising a repair mat and at least one heating element arranged on the repair mat. The repair mat incorporates a plurality of thermally conductive particles, which are integrated into the repair mat. These particles are spaced apart from one another within a structural material of the repair mat. The repair mat is designed to be flexible. The heating element is, for example, arranged on one side of the structural material of the repair mat. The at least one heating element is in thermal and / or mechanical contact with the repair mat.

[0004] DE 10 2016 115 284 A1 describes a repair device for a workpiece made of a plastic material, comprising an induction heating device which is arranged on the workpiece and a repair material which is arranged on a repair area of ​​the workpiece.

[0005] The induction heating device comprises a magnetic field generator and a heat source. The heat source is located between the magnetic field generator and the repair area. The repair device has at least one temperature sensor, which detects whether the repair material is being heated by the heat source. The at least one temperature sensor is connected to a control and / or regulating device. The control and / or regulating device has a storage device in which a temperature profile is stored. The control and / or regulating device controls and / or regulates the temperature measured by the at least one temperature sensor according to the stored temperature profile.

[0006] DE 69636952 T2 discloses a flexible insulated heating element that is wrapped around pipes or other unusually shaped components for heating. The heating element comprises a relatively thin and elastic, non-stretchable heating mat that has either a two-dimensional curvature, such as that found in pipes or other pipelines, or three-dimensional curvatures, such as spheres, saddles, valve bodies, elbow fittings, or T-fittings.

[0007] DE 10243448 B4 describes a flexible heating element, such as an electric blanket, heating pad, or heated underblanket, comprising a heating cord embedded within the element. This cord is connected to an electrical supply line via a section extending outside the element and an electrical wiring component, with the other end of its heating wires terminating within the element. The exposed heating cord section is provided with a heat-insulating, flexible sheath applied to the outer insulation of the heating cord. This sheath is equipped with a kink protection or strain relief component at its transition to the heating element and / or at its further transition to the wiring component.

[0008] WO 99 / 60823 A1 discloses an electric heating element with a heating layer designed as an electric resistance heater, wherein the heating layer is formed from electrically conductive non-metallic fibers embedded in a plastic layer. The electrically conductive non-metallic fibers are in the form of a nonwoven fabric. When epoxy or polyester resin is used to produce the plastic layer, the electric heating element is more or less stiff and rigid and can be shaped according to a desired three-dimensional form, whereas when silicone resin is used to produce the plastic layer, it remains flexible and deformable. The electric heating element with a plastic layer formed from silicone resin is used as a heater for car seats, loungers, beds, electric blankets and thermal blankets, as well as generally for clothing.

[0009] DE 202008011596 U1 discloses a heating element with a composite structure, with an external conductive area with an internal first insulation and a heating conductor embedded therein and an internal second insulation.

[0010] The conductive area completely surrounds the first and second insulation along a conductive path, conducting a trigger current to activate a sensor function. The geometric shape of the heating element can vary depending on the application, for example, as a heating surface such as a flat band, a flat mat, etc., such as flexible heating mats for vulcanization in tires or flexible heating tapes for pipe tracing.

[0011] DE 60132943 T2 discloses a heating pad comprising a mixture of a homogeneous paste made from a thermally conductive particle solid and a liquid metal alloy in a flowable synthetic resin material. The surfaces of the thermally conductive particle solid are wetted with the liquid metal alloy, the liquid metal alloy encapsulating the individual particles that form the thermally conductive particle solid.

[0012] DE 32 37 028 A1 describes a method for manufacturing an elastic and flexible base in the form of a heated seat cushion. A thin electrical conductor is applied to a base in a zigzag pattern and bonded in place.

[0013] US patent 2014 O 317 925 A1 describes a heated repair mat for repairing a wind turbine blade, for example, made of a fiber composite material. In this mat, the heating wire is embedded in a meandering pattern within an elastic carrier material.

[0014] DE 29901225 U1 describes a heating mat for a vehicle seat heating system, in which the heating wire is woven into a knitted layer in a meandering pattern.

[0015] DE 29 08 576 A1 describes a heating mat for a seat heating system of a vehicle seat, in which the heating wire is arranged in a meandering pattern between two firmly connected plastic fleeces.

[0016] DE 69 22 206 U describes an elastic pressure bandage for the heat treatment of body parts, in which an elastically stretchable resistance element with a meanderingly bent heating wire is embedded in rubber-elastic material.

[0017] DE 10 2016 209 487 A1 describes a heating mat for a steering wheel heater in which a heating conductor is applied to a carrier material in the form of a knitted fabric.

[0018] DE 10 2016 209 487 A1 describes a vacuum hood with an induction heating device for repairing composite workpieces, in which a coil assembly is fixed to a textile carrier with a fiber and / or mesh structure by means of retaining threads. The carrier is embedded in the silicone vacuum hood along with the coil assembly and is designed to be flexible. A reinforcing structure can be provided on or in the vacuum hood for reinforcement.

[0019] DE 10 2017 116 931 A1 describes a thermally conductive repair mat and a repair device for repairing composite workpieces, in which thermally conductive particles are embedded in the structural material of the repair mat. The particles can be heated, for example, with an external heating element. Disclosure of the invention

[0020] The object of the invention is to create a heating mat with a flat support and at least one heating element, which can be applied to curved shapes and can be manufactured cost-effectively.

[0021] The problem is solved by the features of the independent claim. Favorable embodiments and advantages of the invention become apparent from the further claims, the description, and the drawing.

[0022] The invention relates to a heating mat with a planar support and at least one heating element made of a wire-shaped or fibrous element connected to the support.

[0023] It is proposed that the support be designed to be reversibly stretchable and have at least one area with the at least one heating element in which the at least one heating element has changes of direction along its length on the support that deviate from a straight course.

[0024] The carrier is designed to be reversibly stretchable with an elongation at break of at least 50% in at least one direction. The at least one heating element is embroidered or sewn onto the carrier and exhibits at least two-dimensional elongation with a stretch reserve of at least 10% when the carrier is stretched.

[0025] Advantageously, the heating element flexibly follows the expansion of the support.

[0026] The wire-shaped or fiber-shaped element can be a metal wire or an electrically conductive, non-metallic fiber, for example a carbon fiber.

[0027] In the heating mat according to the invention, an elongated heating element, made of a wire or fiber, for resistance or induction heating is applied directly to an elastic medium as a carrier and laid, for example, in reciprocating loops or arcs on the surface of the carrier. The heating element thus possesses a reserve of elasticity. If the carrier is stretched, for example, when it is placed on a curved surface of a component, the heating element can flexibly follow the stretching of the carrier in that area by, for example, stretching itself. The heating element is embroidered or sewn onto the carrier. The embroidery process can be machine-assisted, with the embroidery pattern being created on a computer. In this way, a very cost-effective production of the heating mat is possible. The carrier material can be, for example, a silicone mat or silicone rubber.

[0028] The heating element can be arranged on a straight section of the support and have a greater length along its extent than the straight section of the support has in its relaxed state. The heating element typically has an expansion reserve of at least 10%, preferably at least 20%.

[0029] In this way, a doubly curved surface can be represented by the heating mat, which represents a significant advantage over the prior art, where a textile structure consisting of several threads in the warp and weft directions is typically used as the substrate. Such a textile structure lacks elasticity in the plane of the textile structure. Known doubly curved heating mats currently require complex manufacturing processes to adapt them to the shape to be heated and are practically unusable for other shapes.

[0030] In contrast, the heating mat according to the invention has so much elasticity that the heating mat can be applied to multiply curved surfaces in order to, for example, carry out repair procedures on fiber composite structures by placing repair pieces such as laminates on it, heating them up and joining them with the fiber composite structure.

[0031] Such a heating mat can also be used to heat laminates on complexly shaped tools in a suitable manner. This enables efficient manufacturing processes for laminates that do not require autoclaves.

[0032] According to an advantageous embodiment of the heating mat, the at least one heating element can have, at least in certain areas, direction-reversing structures extending parallel to a surface of the support and / or, at least in certain areas, direction-reversing structures projecting from the surface of the support. The area can be two-dimensionally planar on the surface of the support if the direction-reversing structures extend parallel to the surface of the support. However, if the direction-reversing structures project from the surface of the support, the area can even be three-dimensional.

[0033] The directional reversal structures can be, for example, arcs, waves, loops, and / or kinks, allowing the heating elements' wires to be arranged over a greater length on a straight and / or flat support. When the heating mat is curved or bent, the heating element's expansion reserve can then be advantageously utilized to apply the heating mat to a multiply curved surface of a repair structure or to a complexly shaped tool.

[0034] According to an advantageous embodiment of the heating mat, the at least one heating element can be held on the substrate by loops, or at least temporarily held by loops. In particular, the at least one heating element can be embroidered. The heating element can be embroidered onto the substrate, for example, with a thread made of at least one of polyester, aramid, polyamide, or fiberglass. The substrate can, in turn, be made of silicone or, alternatively, of a woven material. Then, using a two-component (2K) process, silicone can be poured onto it so that the heating element is embedded in a 2K silicone mat. The threads that held the heating element can then be removed. The embroidery process can be machine-based, with the embroidery pattern being created on a computer. In this way, a very cost-effective production of the heating mat is possible.

[0035] According to an advantageous embodiment of the heating mat, the substrate can have a Shore hardness of 5 to 60 Shore, in particular 10 to 40 Shore, preferably 20 to 30 Shore. The Shore hardness is defined according to DIN 53505 from the year 2000. These Shore hardness values ​​are typical for silicone.

[0036] According to an advantageous embodiment of the heating mat, the carrier can have a tear resistance of 4 to 100 N / mm², particularly 15 to 100 N / mm², and most preferably 25 to 100 N / mm². The tear resistance values ​​can be determined according to ASTM D 624 B (2000) using a strip test and according to DIN 53515 using an angle test.

[0037] According to an advantageous embodiment of the heating mat, the carrier can have an elongation at break of at least 50% in at least one direction, preferably an elongation at break of 100% to 800%, particularly preferably of 200% to 800%, and most preferably of 500% to 800%, in each case measured according to DIN 53504, S3A from 2017. The elongation at break is specified as a percentage relative to the initial length before stretching. For standard elastomers, the elongation at break is between 100% and 800%. In individual cases with special compounds, this value can be significantly exceeded.

[0038] According to an advantageous embodiment of the heating mat, at least one sensor element can be attached to the carrier, in particular by means of loops. The sensor element can, for example, be a temperature element such as a resistance temperature sensor or a thermocouple, which can also expediently be embroidered into the carrier. In this way, the sensor element can be permanently attached to the heating mat and reliably measure the temperature of the heating mat and / or the heating element.

[0039] According to an advantageous embodiment of the heating mat, the carrier can be made of silicone, preferably of 2K silicone, and / or of a woven material.

[0040] The woven material can be made from an elastic material or also woven or embroidered using another textile technology in such a way that the backing material also has loops or patterns similar to wire-shaped or fibrous elements, which can also be elastically deformed under load.

[0041] The heating element can be embroidered onto the substrate, for example, with a thread made of at least one of polyester, aramid, polyamide, or fiberglass. The substrate can be made of silicone or, alternatively, a woven material. Silicone can then be poured onto it using a two-component (2K) process, embedding the heating element in a 2K silicone mat. The threads holding the heating element in place can then be removed. The embroidery process can be automated, with the design created on a computer. This method allows for very cost-effective production of the heating mat.

[0042] According to an advantageous embodiment of the heating mat, at least one heating element can be designed as a resistance heater. In this way, a laminate or repair piece can be heated directly by the heating mat placed on top of it. This allows for a homogeneous temperature distribution.

[0043] According to an advantageous embodiment of the heating mat, at least one heating element can be designed as an induction heater. In this case, coils with the same winding direction are expediently used as the heating element and are traversed by alternating current. This generates a spatially homogeneous magnetic field, which in turn induces eddy currents in an underlying electrically conductive layer, for example, a metallic one. Instead of a metallic layer, carbon nanotubes or carbon fibers can also be inductively heated.

[0044] These eddy currents heat the metallic layer due to their so-called eddy current losses. If the metallic layer is positioned in the immediate vicinity of the object to be heated, for example a laminate or a repair piece of a fiber composite structure, the object can be effectively heated as a result.

[0045] According to an advantageous embodiment of the heating mat, a vacuum channel can be arranged at least partially at the edge of the carrier. The vacuum channel can expediently be designed to extend all the way around the mat. When the heating mat is placed against a workpiece and the vacuum channel is evacuated, the heating mat is drawn to the surface of the workpiece and assumes its shape. Simultaneously, the heating mat is held in position. This allows the heating process of the workpiece to be carried out efficiently and reliably.

[0046] According to an advantageous embodiment of the heating mat, at least one heating element can be covered with a flexible material. This flexible material can be, for example, silicone, but other plastics with sufficient elasticity and temperature resistance can also be used. In this way, the heating element is embedded in the heating mat and thus mechanically protected against potential damage. Reliable electrical insulation can also be achieved with such an arrangement.

[0047] According to an advantageous embodiment of the heating mat, at least one heating element can be formed from a stranded wire. The stranded wire can consist of a large number of individual wires. Typical stranded wires for induction heating can, for example, comprise several hundred, or 500, individual wires. Such stranded wires exhibit great flexibility, making them particularly suitable for laying the heating wires in curves, bends, kinks, or loops. For resistance heating, stranded wires with a smaller number of individual wires are also possible, for example, 10.

[0048] According to an advantageous embodiment of the heating mat, the substrate and / or the flexible mass can incorporate at least one cooling element. Such a cooling element can effectively dissipate heat generated in the heating mat, for example, from the current-carrying heating wires of an inductive heater, or from the workpiece via heat conduction. In this way, the temperature of the heating mat itself can be kept within a favorable range. For example, temperatures of up to 400°C may be necessary for processing laminates, while the silicone substrate of the heating mat can exhibit degradation at temperatures above 200°C. With such a cooling element, the temperature of the heating mat can be appropriately reduced.

[0049] According to an advantageous embodiment of the heating mat, the at least one cooling element can have at least one cooling line through which a fluid, in particular air, flows. Cooling lines laid on the support can effectively dissipate heat when air flows through them. Alternatively, it is also possible to use fluids such as water as the cooling medium. In this way, effective and cost-efficient cooling of the heating mat can be achieved. Furthermore, the temperature can be regulated within a temperature range favorable for the application by means of such a cooling element. drawing

[0050] Further advantages become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0051] They show, for example: Fig. 1 a section through a heating mat with a heating element arranged on a support according to a first embodiment of the invention; Fig. 2 a section through a heating mat with a heating element arranged on a support according to a further embodiment of the invention, wherein the heating element is covered with a flexible mass; Fig. 3 a section through a heating mat with a heating element arranged on a carrier according to a further embodiment of the invention, wherein the carrier has a circumferential vacuum channel; Fig. 4 a section through a heating mat with a heating element arranged on a carrier according to a further embodiment of the invention, in which the heating element is embroidered onto the carrier and held by loops of the sewing thread; Fig. 5 a section through a heating mat with a heating element arranged on a carrier according to a further embodiment of the invention, in which the heating element protrudes from the surface of the carrier in arcs; Fig. 6 a schematic top view of a support with several parallel heating elements arranged in wavy lines according to a first embodiment of the invention; Fig. 7 a schematic top view of a support with several parallel heating elements arranged in wavy lines and intersecting each other according to a further embodiment of the invention; Fig. 8 a schematic top view of a support with a heating element formed in zigzag lines according to a further embodiment of the invention; Fig. 9 a schematic top view of a carrier with a heating element designed in a meandering coil shape according to a further embodiment of the invention; Fig. 10 an enlarged view of the heating element according to Fig. 9; Fig. 11 a schematic top view of a support with a wavy-line shaped heating element according to a further embodiment of the invention; Fig. 12 an enlarged representation of the heating element according to Fig. 11; Fig. 13 a section through a heating mat with a heating element arranged on a support according to a further embodiment of the invention, wherein a cooling element is arranged on the support; Fig. 14 a section through a heating mat with a heating element arranged on a support and a cooling element according to a further embodiment of the invention, wherein the heating element and the cooling element are covered with a flexible mass; Fig. 15 a section through a heating mat with a heating element arranged on a carrier and a cooling element according to a further embodiment of the invention, wherein the carrier has a circumferential vacuum channel. Embodiments of the invention

[0052] In the figures, similar or equivalent components are numbered with the same reference symbols. The figures merely show examples and are not to be understood as limiting.

[0053] The directional terminology used below, including terms like "left," "right," "above," "below," "in front," "behind," "after," and the like, serves only to improve the understanding of the figures and is in no way intended to limit their generality. The components and elements depicted, their interpretation, and their use may vary according to the considerations of a person skilled in the art and be adapted to the specific applications.

[0054] Fig. Figure 1 shows a section through a heating mat 100 with a heating element 50 arranged on a support 10 according to a first embodiment of the invention.

[0055] The heating mat 100 has a planar support 10 and at least one heating element 50 made of a wire 51, which is connected to the support 10. It is understood that an electrically conductive fiber can also be used instead of a wire 51.

[0056] In this embodiment, the heating element 50 is arranged on the surface 44 of the support 10. A plurality of wires 51 can be seen in the cross-section of the heating element 50, of which, for the sake of clarity, only three are designated with the reference numeral 51. The wires 51 can be formed as individual wires. However, they can also be connected to each other in front of and / or behind the plane of the cross-section.

[0057] The support 10 is designed to be reversibly stretchable and has at least one area 20 with the at least one heating element 50 in which the at least one heating element 50 has changes of direction along its length on the support 10 that deviate from a straight course.

[0058] The heating element 10 can be arranged on the straight section 20 of the support 10 and have a greater length along its extent than the straight section 20 of the support 10 has in the relaxed state of the support 10. A strain reserve can typically be at least 10%, preferably at least 20%.

[0059] The length of the heating element 50 is, for example, in Fig. 6 is designated with the reference numeral 30 and represents the physical length of the heating element 50 from its beginning to its end, which can be measured when the curved heating element 50 is pulled straight out along its length.

[0060] The heating element 50 has, at least in some areas 20, direction-reversal structures 23 such as arcs, waves and / or kinks that extend parallel to a surface 44 of the support 10. However, the direction-reversal structures 24 can also project, at least in some areas, away from the surface 44 of the support 10, as in the embodiment shown in Fig. 5 is shown.

[0061] The carrier 10 can, for example, be made of silicone, preferably of 2K silicone. Alternatively, it is also possible for the carrier 10 to be made of a woven material.

[0062] At least one heating element 50 can be designed as a resistance heater. For this purpose, heating wires 51 with a relatively high resistance are preferably used, which are supplied with direct or alternating current.

[0063] Alternatively, the heating element 50 can also be designed as an induction heater. In this case, heating wires 51 with the lowest possible resistance are used, arranged in the form of individual coils with the same winding direction and supplied with alternating current. The magnetic field generated can induce eddy currents in a nearby electrically conductive heat-generating element, such as a metallic layer. These eddy currents, through their electromagnetic losses, cause the heat-generating element to heat up. This generated heat can then be transferred to a workpiece, such as a laminate.

[0064] The heating wire 51 of the heating element 50 can be formed from a stranded wire. Such a stranded wire exhibits high flexibility and can be easily arranged with changes in direction, such as bends, on the carrier 10.

[0065] The support material 10 can have a Shore hardness of 5 to 60 Shore, in particular 10 to 40 Shore, preferably 20 to 30 Shore. Its tensile strength can be 4 to 100 N / mm², in particular 15 to 100 N / mm², and most preferably 25 to 100 N / mm². The support 10 can further exhibit an elongation at break of at least 50% in at least one direction, preferably 100% to 800%, particularly preferably 200% to 800%, and most preferably 500% to 800%.

[0066] In Fig. Figure 2 shows a cross-section through a heating mat 100 with a heating element 50 arranged on a carrier 10 according to a further embodiment of the invention, in which the heating element 50 is covered with a flexible material 16. This flexible material can, for example, be silicone, which is poured over the heating element 50 arranged on the carrier 10 in a casting process. In this way, after the flexible material 16 has cured, the heating element 50 is firmly embedded in the finished structure consisting of the carrier 10 and the flexible material 16. The heating mat 100 can thus still exhibit the necessary flexibility and elasticity.

[0067] In Fig. Figure 3 shows a section through a heating mat 100 with a heating element 50 arranged on a carrier 10 according to a further embodiment of the invention, in which the carrier 10 has a circumferential vacuum channel 90.

[0068] A vacuum channel 90 is arranged at least partially along the edge of the carrier 10. The vacuum channel 90 can advantageously be designed to extend all the way around the carrier. When the heating mat 100 is placed against a workpiece and the vacuum channel 90 is evacuated, the heating mat 100 is drawn to the surface of the workpiece and assumes its shape. Simultaneously, the heating mat 100 is held in position. This allows the heating process of the workpiece to be carried out efficiently and reliably.

[0069] Fig. Figure 4 shows a section through a heating mat 100 with a heating element 50 arranged on a support 10 according to a further embodiment of the invention, in which the heating element 50 is held by loops 32, for example in the form of individual threads.

[0070] In particular, one of the heating elements (50) can be embroidered. This can be done, for example, by stitching loops of a sewing thread made of polyester, aramid, polyamide, or fiberglass onto the backing. The embroidery process can be done by machine, with the embroidery pattern created on a computer. This allows for very cost-effective production of the heating mat.

[0071] The carrier 10 can be made of silicone or, alternatively, of a woven material. Optionally, silicone can be poured onto it using a two-component (2K) process, so that the heating element 50 is embedded in a 2K silicone mat. In an alternative embodiment not according to the invention, the threads with which the heating element 50 was held can also be removed again by separating and peeling them off on the outer surface 12.

[0072] Furthermore, in the exemplary embodiment in Fig. 4. A sensor element 80 is visible on the carrier 10, which is also attached by means of loops 33 of a sewing thread. The sensor element 80, which can be, for example, a temperature sensor, can be embroidered on the surface 44 of the carrier 10 like the heating element 50.

[0073] Fig. Figure 5 shows a section through a heating mat 100 with a heating element 50 arranged on a support 10 according to a further embodiment of the invention, in which the heating element 50 projects from the surface 44 of the support 10 in arcs 24. The area 20, in which the heating element 50 has direction-reversal structures 23, extends in Fig. 5 firstly parallel to the surface of the support 10. However, in this embodiment, the heating element 50 also has direction-reversal structures 24 which point away from the surface 44 of the support 10, so that the area 22 is perpendicular to the surface 44.

[0074] The arcs 24 of the heating wires 51 can be connected to each other. However, they can also be configured as arcs 24 of different heating wires 51 arranged side by side.

[0075] In the Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. Figure 12 shows schematic top views of carriers 10 with various arrangements, in particular embroidery patterns, of heating elements 50, 52, 54, 56, 58 attached to the carrier.

[0076] Fig. Figure 6 shows a first embodiment of a heating element 50 with heating wires 51 arranged side by side in a wave-like pattern. Each individual heating wire 51 has successive arcs forming a direction-reversal structure 23. The heating element 50 is arranged two-dimensionally in the straight, mutually perpendicular sections 20, 21. The length 30 of a wire 51 is greater than the length of the straight section 20, so that when the support 10 (not shown) is stretched, the heating element 50 has a certain reserve of elasticity and can thus flexibly follow the stretching of the support 10. When the support 10 is stretched in the direction of section 21, the heating element 50 can also be easily stretched, as the heating wires 51 are then pulled apart.In the event of a curvature or bending of the heating mat 100, the expansion reserve of the heating element 50 can therefore be used advantageously to apply the heating mat 100 to a multiply curved surface of a repair structure or to a complexly shaped tool.

[0077] The individual heating wires 51 can be energized separately. Alternatively, they can also be connected in series outside of areas 20, 21, so that the heating element 50 has only a single wire 51. It is understood that an electrically conductive fiber can also be used instead of a wire 51.

[0078] The two-dimensional extensibility of the heating elements 50, 52, 54, 56, 58 during an extension of the flexible planar support 10 of the heating mat 100 in the areas 20, 21 is also in the following, in the Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. The embodiments illustrated in Figure 12 with different arrangements of heating elements 52, 54, 56, 58 ensure this. However, in all embodiments of heating elements 50, 52, 54, 56, 58, a certain expansion reserve in the third dimension of the area 22 is also provided, as shown in Figure 12. Fig. 5 shown, given.

[0079] Fig. Figure 7 shows a schematic arrangement of a heating element 52 according to a further embodiment of the invention. In this embodiment, two heating elements 50 are shown, as in Fig. Figure 6 shows the heating element 52 rotated by 90° and placed one on top of the other. In this way, an increased effective current density of the heating element 52, and thus an increased heating power compared to the heating element 50, can be achieved. The individual heating wires 53 can be arranged as in the exemplary embodiment in Fig. 6 can be individually controlled or connected in series.

[0080] In Fig. Figure 8 shows a schematic arrangement of a heating element 54 according to a further embodiment of the invention. Here, a single wire 55 with direction-reversal structures 23 is laid in a zigzag arrangement and loops. Even with such an embodiment of a heating element 54, a good expansion reserve of the heating element 54 can be achieved when the support 10 is stretched. It is understood that an electrically conductive fiber can also be used instead of a wire 55.

[0081] In Fig. Figure 9 shows a schematic arrangement of a heating element 56 according to a further embodiment of the invention, in which a wire 57 is laid in the form of a flat coil with the terminals 40, 42. In order to achieve advantageous elasticity of the heating element 56, the wire 57 is not laid straight along the straight sections 20, 21, but in a meandering pattern with changes of direction 23, resulting in a significantly greater length 30 of the wire 57 than corresponds to the length of the straight sections 20, 21. It is understood that an electrically conductive fiber can also be used instead of a wire 57.

[0082] Fig. Figure 10 shows an enlarged view of the heating element 56. Fig. 9, in which the meandering changes of direction 23 of the laying of the wire 57 can be seen.

[0083] In Fig. Figure 11 shows a schematic arrangement of a heating element 58 according to a further embodiment of the invention. In this embodiment, a wire 59 is laid out in the form of zigzag-shaped changes of direction 23 and larger loops. The heating element 58 is thus designed as a wire loop with the adjacent terminals 40, 42. It is understood that an electrically conductive fiber can also be used instead of a wire 59.

[0084] Fig. Figure 12 shows an enlarged representation of the heating element 58. Fig. 11, in which the shape of the zigzag-shaped changes of direction 23 and larger loops can be clearly seen.

[0085] In the Fig. 13, Fig. 14 and Fig. Figure 15 shows embodiments of a heating mat 100, which has a cooling element 60. The cooling element 60 can have at least one cooling line 62 through which a fluid, in particular air, flows. Two cooling lines 62 are shown in each figure.

[0086] The other specifications of the heating mat 100 correspond to those in the Fig. 1, Fig. 2 to Fig. The three illustrated embodiments are described below. To avoid unnecessary repetition, the description of the... Fig. 1, Fig. 2 to Fig. 3 referred.

[0087] In the exemplary embodiment in Fig. In section 13, the cooling element 60, like the heating element 50, is arranged on the surface 44 of the carrier 10. Both the heating element 50 and the cooling element 60 can be conveniently stitched onto the carrier 10 and thus reliably attached while maintaining the desired flexibility and elasticity. In this way, both the heating element 50 and the cooling element 60 can exhibit sufficient elastic reserve against any stretching of the flexible carrier 10.

[0088] Fig. Figure 14 shows a cross-section through a heating mat 100 with a heating element 50 and a cooling element 60 arranged on a support 10, according to a further embodiment of the invention, in which the heating element 50 and the cooling element 60 are covered with a flexible material. This means that both the heating element 50 and the cooling element 60 are embedded in the heating mat 100 and protected against possible damage from external influences.

[0089] Fig.Figure 15 shows a section through a heating mat 100 with a heating element 50 and a cooling element 60 arranged on a carrier 10 according to a further embodiment of the invention, in which the carrier 10 has a circumferential vacuum channel 90. Both the heating element 50 and the cooling element 60 are partially immersed in the carrier 10, as can be achieved by casting the carrier 10 with, for example, silicone. 10 Carrier material 12 Outside 16 Masse Area 20 Area 21 Area 22 23 Direction reversal structure 24 Direction reversal structure 30 Length heating element 32 loops 33 loops 40 connection 42 connection 44 surface 50 heating elements 51 wire 52 Heating element 53 wire 54 Heating element 55 wire 56 Heating element 57 wire 58 Heating element 59 wire 60 cooling elements 62 Cooling line 80 sensor elements 90 Vacuum channel 100 heating mats

Claims

[1] Heating mat (100) with a planar support (10) and at least one heating element (50, 52, 54, 56, 58) made of a wire-shaped or fibrous element (51, 53, 55, 57, 59) connected to the support (10), wherein the support (10) has at least one area (20, 21, 22) with the at least one heating element (50, 52, 54, 56, 58) in which the at least one heating element (50, 52, 54, 56, 58) has changes of direction along its length (30) on the support (10) that deviate from a straight course, characterized by , that the carrier (10): is designed to be reversibly stretchable with an elongation at break of at least 50% in at least one direction and the at least one heating element (50, 52, 54, 56, 58) is embroidered or sewn onto the carrier (10) and has at least two-dimensional elongation capability with an elongation reserve of at least 10% when the carrier (10) is stretched. [2] Heating mat according to claim 1, characterized by , that the at least one heating element (50, 52, 54, 56, 58) in the area (20, 21, 22) has at least partially direction-reversal structures (23) that extend parallel to a surface (44) of the support (10) and / or that at least partially direction-reversal structures (24) protrude from the surface (44) of the support (10). [3] Heating mat according to claim 1 or 2, characterized by , that the at least one heating element (50, 52, 54, 56, 58) is held on the carrier (10) by loops (32) or is held at least temporarily by loops (32), in particular that the at least one heating element (50, 52, 54, 56, 58) is embroidered, in particular with a thread made of at least one of polyester, aramid, polyamide, or glass fiber. [4] Heating mat according to any one of the preceding claims, characterized by , that the support (10) has a Shore hardness of 5 to 60 Shore, in particular of 10 to 40 Shore, preferably of 20 to 30 Shore. [5] Heating mat according to any one of the preceding claims, characterized by , that the support (10) has a tear resistance of 4 to 100 N / mm, in particular of 15 to 100 N / mm, particularly preferably of 25 to 100 N / mm. [6] Heating mat according to any one of the preceding claims, characterized by that the support (10) has an elongation at break of 100% to 800% in at least one direction, preferably of 200% to 800%, particularly preferably of 500% to 800%. [7] Heating mat according to one of the preceding claims, characterized by , that at least one sensor element (80) is attached to the carrier (10), in particular by means of loops (33). [8] Heating mat according to any one of the preceding claims, characterized by , that the carrier (10) is made of silicone, preferably of 2K silicone, and / or is made of a woven material. [9] Heating mat according to any one of the preceding claims, characterized by, that at least one heating element (50, 52, 54, 56, 58) is designed as a resistance heater. [10] Heating mat according to any one of the preceding claims, characterized by , that at least one heating element (50, 52, 54, 56, 58) is designed as an induction heater. [11] Heating mat according to one of the preceding claims, characterized by , that at least in some areas a vacuum channel (90) is arranged at the edge of the support (10). [12] Heating mat according to one of the preceding claims, characterized by , that at least one heating element (50, 52, 54, 56, 58) is covered with a flexible mass (16). [13] Heating mat according to any one of the preceding claims, characterized by , that at least one heating element (50, 52, 54, 56, 58) is formed from a stranded wire. [14] Heating mat according to any one of the preceding claims, characterized by that the support (10) and / or the flexible mass (16) has at least one cooling element (60). [15] Heating mat according to claim 14, characterized by , that the at least one cooling element (60) has at least one cooling line (62) through which a fluid, in particular air, flows.

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