EP2056650B1 - Holder for an electric heater, electric heating device and method for its production - Google Patents

Description

Field of application and state of the art

The invention relates to a support for an electric heater, which consists of insulating material and on the upper side at least one heating element is arranged. The heating element is elongated and runs in tracks on the top of the carrier. Furthermore, the invention relates to an electric heater with such a carrier and a method for producing such an electric heater.

It is for example from the EP 612 197 A1 known to form an electric heater in the form of a radiant heater with a similar carrier in which heating elements in the form of Bandheizleitern run in grooves in a prefabricated path on top of the carrier. At certain intervals on the tracks are the side walls the tracks and laterally pressed against the Bandheizleiter to mechanically secure them. A fuse against overtemperature or a kind of temperature sensor is designed as a known rod controller, which is attached to one side of the radiant heater and the heating elements overlaps because it extends to the opposite side.

From the US 3612826 For example, a similar electric heater is known with a carrier for heating conductors on top of this carrier in corresponding grooves. A Klixon rests on a mat underneath it with lateral projections under this support.

From the WO 00/28786 A1 an electric heating device with a carrier is known, are arranged on the heating elements, wherein a temperature sensor is provided. The temperature sensor is inserted as an elongated sensor from below or from the side into the heater and protrudes with a sensor end having a temperature sensor in the heating zone above the carrier.

From the DE 102005025896 A1 It is known to provide optical temperature sensors directly to the side of the heater or in its central region in an electric heater.

From the DE 2500586 A1 it is known to arrange a temperature detection of a thermohydraulic temperature controller in the central region of an electric heater. This is pressed from below in a guide resiliently upwards against the underside of a hob plate on the heater for good thermal contact.

From the DE 102005005527 A1 an induction heating device is known which has an electrical temperature sensor in a central region.

From the DE 3717728 A1 Another electric heating device is known, which has a contactless pot detection. For this purpose, a proximity switch with sensor elements is provided, which are arranged in a central region of the heating device and are directed from below against a hob plate above the heating device.

Task and solution

The invention has for its object to provide a support mentioned above, an electric heater with such a carrier and a method for producing such a heater with which problems and disadvantages of the prior art can be avoided and in particular in the simplest possible way a kind of temperature sensor or a Klixon can be provided.

This object is achieved by an electric heater with the features of claim 1 and a method according to claim 10. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below. Some of the features are described only for one embodiment of the carrier, the heater or the method, but should also apply independently to the other versions. The wording of the claims is incorporated herein by express reference.

According to the invention, an opening is provided in a central region of the carrier, through which a so-called Klixon can be introduced or pushed through. The term klixon is to be understood in this application generally a thermally actuated switch, which is triggered by thermally triggered spring means, advantageously a bimetal snap-action disc, thereby opening a contact, so interrupts the power line when a certain temperature is exceeded. This particular temperature is determined by the formation of the bimetallic snap disk. The following is for the term Metal snap disc set. In the following, the term Klixon should be used for this purpose, but without limiting the scope of protection of the application. At the top, the Klixon protrudes over the opening with side projections in the manner of wings, preventing it from falling through. This introduction or insertion of the Klixons takes place from the upper side in such a way that electrical connections of the Klixons project beyond the underside of the carrier or can be reached there. By bending the terminals or attaching a connection device such as a plug or attaching connection cables or the like. can be reliably prevented from moving back or fall out of the Klixons. Under certain circumstances, it is not even necessary that the electrical connections protrude far beyond the underside. Here, an attachment of electrical connections is possible such that they overlap the opening in the carrier from the bottom so that a moving back or falling out of the Klixons is not possible. In an embodiment of the invention, the Klixon can be inserted in the opposite direction from bottom to top, and then the said lateral projections are bent at the top as a safeguard against falling out. In an embodiment of the invention, the Klixon can be resiliently attached to the carrier, for example by means of the aforementioned lateral wings odgl.

This type of attachment can be chosen for both a Klixon and for two Klixons, if two such switches should be needed for two different temperature switching points. Furthermore, a kind of double Klixon can be mounted in this way be contained in a housing two Klixons and has four electrical connections.

An aforementioned Klixon is used for a residual heat indicator of the heater, especially when used in a cooktop. Another Klixon can serve as overtemperature protection not to exceed a temperature of 175 ° C on the top of a ceramic hob plate of the hob, since such keep-warming radiators are usually operated not clocking, but are operated permanently with a constant power after switching ,

The carrier is particularly advantageous entirely made of insulating material. It may advantageously be designed in the manner of a flat plate or a disk with a peripheral edge at the top. This edge can survive a little over the heating elements or the paths provided for them and the side walls of the webs, for example a few millimeters. Furthermore, such a peripheral edge can survive even over the set on the top prescribed Klixon, so that no extra recesses must be made for this. The edge should then rest against the underside of a hob plate.

On the one hand, the underside of the carrier may be substantially flat. Alternatively, at least one projecting attachment region can be provided on its underside, which is preferably integrally formed, that is, produced at the same time, wherein it can alternatively also be subsequently attached, for example adhesively bonded. Particularly advantageous two such mounting areas are provided on the underside, which are in particular the same design. Such a fastening region projects over at least the underside of the carrier, possibly also over the side edge. It serves, for example, the carrier or the electric heating device constructed with it as a hotplate to a hob under a glass ceramic hob plate to attach. For this purpose, the attachment region has at least one prefabricated opening into which a fastening screw or the like. can be screwed. It is also possible to provide a plurality of such openings in order to allow a different positioning with fine adjustment of the carrier.

In a further embodiment of the invention, the carrier may be formed relatively thin, for example, be about 10mm to 15mm thick. The thermal insulation is sufficiently ensured, especially if the finished heater does not cause excessive temperature development. This is the case in particular when the heating device is designed as a so-called heated radiator. This means that in a food preparation, no large energy inputs are possible, but a provided with this heater cooking surface on a hob for keeping warm pots and the food is used. For this purpose, the power of the heating element or the heating device can be between 100 watts and 150 watts, in particular with a power density for the carrier of 0.6 W / cm ² .

Connections of the heating element to the electrical connection can advantageously be guided in a central region of the carrier with distance from the outer edge so that they extend from an upper side of the carrier through the carrier to a lower side and are easily accessible there for electrical contacting or for mechanical fastening. The mechanical attachment is achieved through the electrical connection, so to speak. This means in a simple embodiment that the terminals or terminal ends of the heating element are inserted through the carrier and survive at the bottom and connected there to a supply line or a connection cable. As a result, a simple electrical connection can be achieved, which does not necessarily have to be at the edge, as is usual with other radiant heaters or similar heating devices, but in the middle area. Furthermore, the connections are mechanically secured or secured against movement by the surrounding material of the carrier. Finally, it can be prevented by attaching the leads or connecting cables, that the connections move back again or the heating element dissolves in this area of the carrier. An electrical connection in the middle of the underside of the carrier is also more accessible in many cases than on an outside of the heater.

Advantageously, connection cables can be brought laterally or approximately parallel to the underside of the carrier to the terminals of the heating elements and then connected to these, preferably welded. Especially when the brought up connecting cables cross the connections of the heating elements such that they protrude to the two sides over the opening for passing through the connections and securely and reliably secure the connections against being moved back. Due to the compliance of the carrier, at least when made of a suitable insulating material, the terminals of the heating elements can also be bent at least 30 ° to 45 °, and then connected to the connecting cables.

According to a further embodiment of the invention, the tracks for the heating elements are recessed in the carrier and have, at least in sections, side walls which in particular run relatively close to the heating element. At least in part, the side walls or portions of the side walls are adapted to secure the heating elements in the webs against lifting from the carrier by being pressed in such a way that they also incline over the web at least on one side for engaging both the web and Also, the heating element therein to secure it against lifting from the carrier. Thus, in this embodiment, a retaining sidewall portion is not laterally adjacent to the heating element, but overlaps it from above. Although he can rest against the heating element, it is however unnecessary. While only a non-positive retention of the heating element in the web is possible by lateral pressing against the heating element, by a spreading of the side wall portions a positive mounting is possible, which holds much better. This is from the aforementioned EP 612 197 A1 known.

Alternatively, the heating element may be formed in the form of coiled wire, in particular round-spiraled, and pressed wide from above. So it is with pressure on the side wall areas, which causes the same holding effect as described above. Under certain circumstances, it is also something pressed into the side wall areas for even better support.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combination in one embodiment of the invention and in other areas be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into individual sections as well as intermediate headings does not restrict the general validity of the statements made thereunder.

Brief description of the drawings

Fig. 1

eine Ansicht von schräg oben auf einen Träger ohne weitere Zusatzteile,

Fig. 2

eine Draufsicht auf eine elektrische Heizeinrichtung gemäß der Erfindung mit einem Träger aus Fig. 1 und darin angeordnetem Heizelement sowie Klixon,

Fig. 3

einen Schnitt durch die Heizeinrichtung aus Fig. 2 und

Fig. 4

eine Schrägansicht von unten auf die Unterseite der Heizeinrichtung aus Fig. 3 mit Vergrößerung der Anordnung und Befestigung eines Klixons.

Embodiments of the invention are shown schematically in the drawings and will be described in more detail below. In the drawings show:

Fig. 1

a view obliquely from above on a carrier without further accessories,

Fig. 2

a plan view of an electric heater according to the invention with a carrier Fig. 1 and heating element arranged therein as well as Klixon,

Fig. 3

a section through the heater off Fig. 2 and

Fig. 4

an oblique view from below on the underside of the heater Fig. 3 with enlargement of the arrangement and attachment of a Klixons.

Detailed description of the embodiments

In Fig. 1 is an oblique view obliquely from above on a support 11 is shown. The plate or disc-like carrier 11 has an upper side 12 and a lower side 13. At the top 12 extends around a slightly raised edge 14. The carrier 11 is made of suitable material in one piece in a single pressing operation.

On the top 12 tracks 16 are formed, which go slightly deeper than half the thickness of the wearer. The tracks run meandering for a heating element with a few turns and start and end in a central area. There, at least one hole 17 a can be seen, which leads at the end of the web 16 through the carrier 11 to its underside 13. In addition to the holes 17 for connections of the heating elements, an opening 22 is provided in the central region. Through this, as explained in more detail below, a Klixon be plugged as a temperature switch.

Furthermore, the webs have different portions as extended portions 19 and protrusions 20 therebetween. The supernatants 20 serve to be pressed into the tracks after insertion of the heating element and then move over the web for reaching over and holding the heating element.

In Fig. 2 is a plan view of an electric heater 23 is shown, which consists of a carrier 11 according to Fig. 1 consists, in which a heating element 24 is inserted in the webs 16. The heating element 24 consists of round-wound heating wire, for example of a FeCrAl alloy. Terminals 26a and 26b are inserted through the respective holes 17a and 17b at the beginning and end of the tracks 16, as are the holes Fig. 3 better shows. After inserting the heating elements 24 in the tracks 16 according to Fig. 2 Pressure is exerted on the supernatants 20 from above, so that they are further deformed and tilt inward or are pressed inwards over the tracks 16 and thus also over the heating elements 24 located therein. In so doing, they can touch the heating elements 24 when reaching over but they do not necessarily have to.

A Klixon 28 is inserted from above into the opening 22, advantageously after the insertion of the heating elements 24 and pressing. In this case, projecting lateral projections 30a and b on the opening 22 and lie on the top 12 of the carrier 11. They may also be pressed into corresponding recesses, so that the Klixon 28 does not protrude beyond the plane of the top 12, that is sunk.

After the step of crimping the projections 20 and inserting the clip 28, the electric heater 23 is in a state as it is Fig. 3 shows in section. It will be appreciated that the projections 20 protrude above the heating elements 24, at least where provided, and mechanically support them. Furthermore, it can be seen how at least one connection 26a extends through the hole 17a in the support 11 to the underside 13. Here, a connection cable 27 is brought to the end of the connection 26a projecting beyond the underside 13 and welded. Thus, not only an electrical contact, but also a mechanical attachment of the terminal 26a against moving back. The same thing happens at the other terminal 26b. A connection 29a of the Klixon is also shown and projects obliquely over the underside 13.

Left in Fig. 3 dashed a protruding mounting dome 31 is shown, which may be integrally formed in particular integrally on the carrier 11 as a further embodiment of the invention. It has two mounting holes 32 on an underside, which are designed so that conventional fastening screws can engage and thereby themselves cut a thread. Advantageously, two such attachment domes 31 are provided, in particular on opposite outer regions of the support 11.

In Fig. 4 It is shown how a Klixon inserted from the upper side 12 in the opening 22 28 on the bottom 13 with its terminals 29a and 29b is not only accessible for electrical contact, for example by plugging or welding. It can also be seen how the terminals 29a and b of the Klixons 28 project beyond the bottom 13 out of the opening 22 and are bent outwards. Thus, a positive retention of Klixons 28 carried on the carrier 11, which is very easy to do and at the same time, for example, to repair malfunction, allows replacement of the Klixons without much effort. As an alternative to attaching the Klixons 28 by bending the terminals 29a and b can also be a plugging a group connector or other plug done, which then protrudes below the opening 22 and thus causes a support of the Klixons. At the top 12 of the carrier 11 of the Klixon 28 with the protrusions 30 just on so that he can not fall through the opening 22.

Claims (11)

1. An electrical heating device (23) including a support (11) for the heating device (23) for disposing heating elements (24) on a top side (12) of said support, said heating elements (24) being elongated and running in paths (16) on said top side of said support, characterized in that in a central area of said support (11), which is free from said heating elements (24), an opening (22) is provided in said support and from said top side a klixon (28) is inserted into said opening and in part projects laterally over said opening (22) having lateral projections (30a, 30b) in the form of wings for resting on said top side (12) of the support, including electrical terminals (29) projecting over the bottom side (13) of said support (11).
2. The electrical heating device according to claim 1, characterized in that on said bottom side of said support (11) at least one salient fixing area (31) is integrally shaped, said fixing area projecting over a substantially flat bottom side (13) of said support (11).
3. The electrical heating device according to claim 2, characterized in that the fixing area (31) has at least one prefabricated opening (32) for engagement of a fixing screw or the like, said opening being directed away from said support (11).
4. The electrical heating device according to any one of the preceding claims, characterized in that through bending of said terminals (29) after insertion a mechanical fixing of said klixon (28) to said support (11) takes place by said terminals (29) laterally overlapping said opening (22) on said bottom side (13) of said support.
5. The electrical heating device according to any one of the preceding claims, characterized in that said klixon (28) is resiliently fixed to said support, preferably by means of lateral wings on a housing of the klixon (28).
6. The electrical heating device according to any one of the preceding claims, characterized in that an elongated heating element (24), in particular made of resistance wire, runs in said paths (16), said heating element being held in said paths (16) by overlapping said side walls (20) of said paths (16) and/or flattening the heating elements (24).
7. The electrical heating device according to any one of the preceding claims, characterized in that said heating element (24) comprises a helically bent wire.
8. The electrical heating device according to any one of the preceding claims, characterized in that a single heating element (24) is placed on said support (11), and terminals (26) of said heating element passing through said support from said top side (12) to said bottom side (13), and said terminals (26) projecting over said bottom side (13).
9. The electrical heating device according to any one of the preceding claims, characterized in that on said bottom side (13) of said support (11) electrical connecting cables (27) are fixed to said terminals (26) of said heating element for electrical connection purposes and as a result said terminals are mechanically secured for preventing moving back, in particular also for securing of said heating element (24), preferably a connection of said electrical connecting cables (27) to said terminals (26) being very close to said support (11).
10. A method for manufacture of a heating device (23) according to any one of claims 1 to 9, wherein in a central area of said support (11) is provided an opening (22) for inserting a klixon (28) from the top side (12) of the support and in part projecting laterally over said opening (22) for resting on said top side (12) of said support, said klixon having electrical terminals (29) projecting over said bottom side (13) of said support (11) characterized in that after placing said at least one heating element (24) on said support (11) in said paths (16) on said top side (12) of said support a pressure is exerted from above on said heating element (24) in such a way that it is at least sectorwise pressed into said side walls of said paths (16) for fixing said heating element so as to prevent lifting or removal from said paths (16).
11. The method according to claim 10, characterized in that at least one electrical terminal (29) of said klixon (28) projecting over said bottom side (13) of said support (11) is bent, or an electrical attachment plug or electrical connecting cable is so fitted thereto that said klixon (28) is fixed to said support (11) by projecting over said bottom side (13) of said support (11).

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