EP2431666B1 - Cooking hob device - Google Patents

Description

The invention relates to a hob device according to the preamble of claim 1.
It is known in induction hobs to attach heating elements in the form of inductors on a Heizelementträgereinheit made of aluminum and to press them by means of a spring force against a cooktop plate made of glass ceramic.

The publication DE 23 51 249 A1 discloses an electric cooker according to the preamble of claim 1 with a flat hearth covering the entire hearth surface. The stove is made of stainless steel and at the bottom it is plated with saucepan-sized metal plates.
The Utility Model DE 20 2005 016 787 U1 discloses a device for heating food with a heating device, which has a heating element and a planar functional element arranged thereon, and with a supply connection which supplies the heating device with energy. The heater is detachable from the supply port and the functional element is detachable from the heater.
The publication WO 2008/148769 A2 discloses a cooker with an upper plate made of glass or ceramic. The cooking range also has at least one heating device arranged under the upper plate, which is arranged below the upper plate. Furthermore, the cooking stove has a lower plate made of a metal, which is disposed below the upper plate to define a closed volume in which the heating device, electrical and mechanical elements and electrical connections are included. One or more springs are attached to the bottom plate and the heater and cause the heater to abut the top plate to maintain full surface contact.
The publication US 4 031 353 A discloses a radiant heater having a metal hotplate formed with at least one bulged portion separated from is surrounded by a flat transversely extending peripheral flange. Each of the bulged portions has a concavely curved inner surface and a convexly curved outer heat radiating surface. The entire concave surface of each bulged portion is covered with a vitreous enamel coating and a printed electrical heating element circuit is applied to the enamel coating. A circumferential transition area is provided adjacent to the bulged portions and its surrounding flange. The transition regions are shaped to provide tension to the thermal deformation of the heating plate so that the enamel coating is compressed, thereby increasing the dielectric resistance of the coating.
The publication DE 87 02 478 U1 discloses a cooking appliance with an upper mounting plate and at least one arranged in an opening of the mounting plate electric hotplate, which has a recess in the region of its outer lower edge and a holding element which sets the electric hotplate by bracing down into the opening and with at least one effective against rotation between the electric cooking plate and the holding element. The anti-rotation element is provided on the holding element, elastically movable tongue, which cooperates with the recess.
The object of the invention is in particular to provide a generic hob device with increased robustness. The object is achieved by the features of claim 1, while advantageous embodiments and modifications of the invention can be taken from the dependent claims.
The invention is based on a hob device with a Heizelementträgereinheit, which is provided for a support of at least one heating element, wherein the Heizelementträgereinheit has at least one area with at least one predetermined bending point. A "heating element carrier unit" is to be understood in particular a unit to which at least one heating element is fixed in a mounted state with fastening means, in particular by a screw connection and / or a latching connection, and / or supported by the bearing forces of the heating element. Under "provided" should be understood in particular specially designed and / or equipped and / or programmed. The heating element carrier unit preferably has a main extension plane and is advantageously formed by an at least substantially flat plate. By the fact that the Heizelementträgereinheit is formed by a "substantially flat plate" should be understood in particular that at least 50%, preferably at least 70% and more preferably at least 90% of the Heizelementträgereinheit lie in the main plane of extension. Furthermore, the Heizelementträgereinheit may have recesses. Particularly advantageously, the Heizelementträgereinheit is made of a stamped and bent sheet metal part and is preferably at least for the most part of a non-magnetic metal, in particular aluminum when used in an induction hob. A "non-magnetic" metal is to be understood as meaning, in particular, a metal having a permeability of not more than 1.1 and preferably not more than 1.0001. A "heating element" is to be understood in particular an element which is intended to convert electrical energy into heat. In particular, the heating element is a resistance heater or a radiant heater or preferably an induction heater, which is intended to convert electrical energy indirectly via induced eddy currents into heat. A "predetermined bending point" is to be understood, in particular, as meaning a location of the heating element carrier unit which has a stiffness which is deliberately reduced in relation to a bending moment compared to another point. Preferably, the predetermined bending point is characterized by a deliberately reduced area moment of inertia. Preferably, the predetermined bending point is a line along the main extension plane of the Heizelementträgereinheit and in particular from a first edge of the Heizelementträgereinheit to a second edge of the Heizelementträgereinheit, which is particularly advantageous in bending the Heizelementträgereinheit in response to a force a crest line of the bent main extension plane of the Heizelementträgereinheit. Furthermore, the predetermined bending point is in particular that point of the Heizelementträgereinheit, which undergoes a maximum deformation at a force. By such a configuration, a cooktop device can be provided with an increased robustness compared to conventional cooktop devices, as when a force acting on the Heizelementträgereinheit, especially in a drop test of a hob with a hob invention, bending takes place at the predetermined bending point and can be intercepted there by suitable means , Furthermore, existing Heizelementträgereinheiten adapted for operation with a heavier heating element, in particular an induction heater.

The cooktop apparatus comprises a force reduction unit which is provided to reduce a torque acting on the intended bending point of the Heizelementträgereinheit under a mechanical stress. A "force reduction unit" is to be understood, in particular, as a unit other than the heating element carrier unit, which is arranged parallel to the predetermined bending point in terms of a bending moment in the force flow, so that a torque acting on the heating element carrier unit is distributed to a region of the predetermined bending point and to the force reduction unit. As a result, an irreversible deformation of the Heizelementträgereinheit avoided and the robustness of the hob device can be increased.

The power reduction unit has at least one spring element. A "spring element" is to be understood in particular an element that reacts to an action of a force with a change in length and / or deflection in the direction of the force and generates an equal counterforce. Preferably, the spring element is provided, in a mounted state at a bending load around the predetermined bending point, an elastic change in length and / or deflection of at least 0.25 mm, in particular of at least 0.5 mm, preferably of at least 1 mm and more preferably of at least 2 mm to execute. A typical mechanical stress of the spring element, in particular during a drop test of a hob with a hob device according to the invention, remains below a threshold of elasticity of the spring element above which an irreversible deformation of the spring element occurs. As a result, an irreversible deformation of the Heizelementträgereinheit can be avoided structurally simple and inexpensive and the robustness of the hob device can be increased. Furthermore, by a force action of the spring element, the heating element carrier unit can be returned to its original shape after the action of a bending moment. Furthermore, manufacturing tolerances of the Heizelementträgereinheit can be compensated, so that in particular with an induction hob, a gap-free contact between an induction heating and a hob plate can be achieved. Furthermore, material can be saved and less costly material can be used for the heater support unit. Preferably, the spring element consists of a spring steel and particularly advantageous a galvanized spring steel of the type EN 10270-1-SH. This can save costs.

Advantageously, the spring element is formed by a bow spring. A "bow spring" should in particular be understood to mean a substantially rod-shaped component which preferably has at least one bend. A "rod-shaped component" is to be understood in particular as a component whose axial longitudinal extent is at least 5 times, in particular at least 10 times, advantageously at least 15 times and particularly advantageously at least 20 times greater than each transverse extent, preferably perpendicular to the longitudinal extension of the component. In the case of a perpendicular projection on any plane, the bow spring preferably has at most two and preferably at most one closed contour and is in particular different from a pure helical spring. A spring effect of the bow spring results in particular in the case of a mechanical load on the bow spring in the direction of the transverse extent. As a result, an irreversible deformation of the Heizelementträgereinheit can be space-saving avoided and the robustness of the hob device can be increased. Furthermore, an assembly effort can be advantageously reduced and in particular a flexible spring element can be created.

The spring element extends over the predetermined bending point. By the fact that the spring element "extends over the predetermined bending point" should be understood in particular that on a surface of the Heizelementträgereinheit exist at least two points at which the spring element contacts the Heizelementträgereinheit and whose connecting line touches the predetermined bending point in a vertical projection on the surface at least and preferably cuts. As a result, an irreversible deformation of the Heizelementträgereinheit can be particularly effectively avoided and the robustness of the hob device can be increased.

It is also proposed that the spring element in a mounted state has a bias. By the fact that "the spring element in a mounted state has a bias", should be understood in particular that the spring element in a mounted state exerts a force different from a gravitational force, in particular on the Heizelementträgereinheit exerts. Preferably, the spring element in a mounted state has a different geometric shape than in a unmounted state. Preferably, the spring element is changed in an assembled state against an unmounted state by at least 0.25 mm, in particular by at least 0.5 mm, preferably by at least 1 mm and particularly advantageously by at least 2 mm in its extension and / or deflected. In this way, a greater reduction of a torque acting on the predetermined bending point under a mechanical load can be achieved. Furthermore, in a mounted state of a hob with a hob according to the invention a more uniform uniform contact pressure of the heating elements can be achieved on a hob plate.

In a further embodiment of the invention, it is proposed that the heating element carrier unit has a concave receiving region for the at least one heating element and the spring element is arranged at least partially in the receiving region. A "concave receiving region for the at least one heating element" is to be understood in particular a region of the heating element carrier unit which is provided for receiving at least one heating element and which at least partially surrounds the receiving region. By the fact that the Heizelementträgereinheit at least "partially surrounds" the receiving area for the at least one heating element, should in particular be understood that an intersection of at least two surface normals of two wall surfaces of the Heizelementträgereinheit enclosing an angle between 0 ° and 180 °, on the same side of Heizelementträgereinheit lies like the receiving area. A "surface normal" of a surface is to be understood in particular as a straight line which is perpendicular to the surface. By the fact that "the spring element is at least partially arranged in the receiving area" should be understood in particular that at least parts of the spring element are arranged in the receiving area and preferably a major part of the spring element is arranged in the receiving area. A "majority of the spring element" is to be understood here in particular as a part of the spring element which makes up at least 60%, in particular at least 70%, preferably at least 80% and particularly advantageously at least 90% of a total mass of the spring element. By such a configuration can be particularly space-saving avoided irreversible deformation of the Heizelementträgereinheit and the robustness of the hob device can be increased. Furthermore, a safety distance to electronic components of a hob can be maintained.

Furthermore, it is proposed that the heating element carrier unit has at least one recess which causes at least in part an increased flexibility in a partial region of the predetermined bending point. A "recess" is to be understood in particular as a material recess, preferably on an edge of the heating element carrier unit. As a result, a predetermined bending point with a purposefully reduced area moment of inertia can be created in a structurally particularly simple and cost-effective manner.

In a preferred embodiment of the invention it is proposed that the Heizelementträgereinheit has at least one parked edge in which the at least one recess is arranged. A "parked edge" is to be understood in particular a bent edge of the Heizelementträgereinheit, preferably with the main extension plane of the Heizelementträgereinheit an angle between 60 ° and 120 °, in particular between 75 ° and 105 °, advantageously between 85 ° and 95 ° and particularly advantageous of 90 °. Particularly advantageously, the Heizelementträgereinheit is made of a stamped and bent sheet metal part and the parked edge formed by deep drawing of the edge zone of the punching and bending sheet metal part. In this way, a particularly large difference between a rigidity of the predetermined bending point and the rigidity of a location of the heating element carrier unit which differs from the predetermined bending point can be achieved.

Further advantages can be found in the following drawing descriptions. In the drawings, an embodiment of the invention is shown. The drawings, the descriptions and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

eine Kochfeldvorrichtung mit einer Heizelementträgereinheit und einer Kraftminderungseinheit in einer Draufsicht,

Fig. 2a

eine Bügelfeder der Kraftminderungseinheit aus Fig. 1 in einer perspektivischen Darstellung,

Fig. 2b

die Bügelfeder aus Fig. 2a in einer Draufsicht entlang einer Richtung IIb in Fig. 2a,

Fig. 2c

die Bügelfeder aus Fig. 2a in einer weiteren Draufsicht entlang einer Richtung IIc in Fig. 2a,

Fig. 3a

die Kochfeldvorrichtung aus Fig. 1 in einer Schnittdarstellung entlang einer Linie III-III in Fig. 1 und

Fig. 3b

die Kochfeldvorrichtung aus Fig. 1 ohne Bügelfeder in einer Schnittdarstellung entlang einer Linie III-III in Fig. 1.

Show it:

Fig. 1

a hob device with a Heizelementträgereinheit and a power reduction unit in a plan view,

Fig. 2a

a bow spring of the power reduction unit Fig. 1 in a perspective view,

Fig. 2b

the bow spring off Fig. 2a in a plan view along a direction IIb in Fig. 2a .

Fig. 2c

the bow spring off Fig. 2a in a further plan view along a direction IIc in Fig. 2a .

Fig. 3a

the hob device Fig. 1 in a sectional view along a line III-III in Fig. 1 and

Fig. 3b

the hob device Fig. 1 without bow spring in a sectional view along a line III-III in Fig. 1 ,

Fig. 1 shows a cooktop apparatus of an induction cooktop with a Heizelementträgereinheit 10, which is provided for a support of two heating elements, and this includes a concave receiving portion 22 for the heating elements. The Heizelementträgereinheit 10 represents a substantially flat plate having a substantially rectangular outline with rounded corners. The Heizelementträgereinheit 10 has a plurality of recesses 27, which are provided for attachment of the heating elements, to a passage of power supply lines and to a mounting of the Heizelementträgereinheit 10 itself. The Heizelementträgereinheit 10 consists of an aluminum sheet with a thickness of 1.2 mm. The Heizelementträgereinheit 10 is formed from a stamped bending plate part. In order to increase the stability, the heating element carrier unit 10 comprises a peripheral, parked edge 26. In a region 12, the heating element carrier unit 10 has a predetermined bending point 14, at which the heating element carrier unit 10 preferably bends under mechanical stress. The predetermined bending point 14 represents a desired bending axis 29 of the heating element carrier unit 10, which extends along a shortest distance from a first edge 28 to a second edge 30 of the heating element carrier unit 10. To increase the flexibility of the Heizelementträgereinheit 10 in a portion of the predetermined bending point 14 has a rectangular recess 24 which is disposed in the parked edge 26 (see Fig. 3b ). The parked edge 26 is slotted in a region of the recess 24 and then bent inwards in the direction of the receiving region 22, so that two wings 42, 44 arise (see Fig. 1 and Fig. 3b ).

In order to prevent an irreversible deformation of the Heizelementträgereinheit 10 in a portion of the predetermined bending point 14, the cooktop device on a power reduction unit 16, which is intended to reduce a force acting on the predetermined bending point 14 of the Heizelementträgereinheit 10 torque under mechanical stress. For this purpose, the power reduction unit 16, a spring element 18, by a bow spring 20 is formed. As in the Fig. 2a, Fig. 2b and Fig. 2c shown, the bow spring 20 consists of a bent rod-shaped component made of spring steel of the type EN 10270-1-SH. The bow spring 20 has two legs 32, 34, which enclose an angle of approximately 170 ° in an unassembled, relaxed state and are separated by a middle piece 40. The middle piece 40 consists of two short bars 46, 48 compared to the legs 32, 34, which in an unassembled, relaxed state enclose an angle of approximately 100 °. The web 46 includes with the leg 32 at an angle of 145 °. Likewise, the web 48 includes with the leg 34 at an angle of 145 °. The two webs 46, 48 of the middle piece 40 lie in a first plane which is perpendicular to a second plane which contains the legs 32, 34 (see FIG Fig. 2c ). Furthermore, close to the legs 32, 34 angled plug ends 36, 38 which lie in the second plane. The plug-in ends 36, 38 are intended to be plugged into specially provided for this purpose plug holes 50, 52 in the Heizelementträgereinheit 10.

As in Fig. 1 and Fig. 3a shown, the spring element 18 extends beyond the predetermined bending point 14. The spring element 18 is arranged completely in the receiving area 22 except for its center piece 40. The middle piece 40 of the spring element 18 is mounted with prestress under the wings 42, 44. The mating ends 36, 38 are inserted into the plug holes 50, 52 of the heater support unit 10 and project minimally through the heater support unit 10 (see FIG Fig. 3a ). Due to the bias, the legs 32, 34 and the middle piece 40 of the spring element 18 are in an assembled state directly to the Heizelementträgereinheit 10 at. In an assembled state, the legs 32, 34 and the middle piece 40 of the spring element 18 are arranged in a plane which is parallel to a main extension plane of the Heizelementträgereinheit

Compared with a mechanical load, the heating element carrier unit 10 exhibits a minimum rigidity with a torque acting in the direction of the desired bending axis 29 (see FIG Fig. 1 ). In a torque acting in the direction of the desired bending axis 29, the heating element carrier unit 10 is bent in the region 12 about the desired bending axis 29. A part of the torque acts on the bow spring 20. Thus, an irreversible deformation of the Heizelementträgereinheit 10 in the area 12 can be avoided.

reference numeral

10

Heizelementträgereinheit

12

Area

14

Predetermined bending point

16

Force reduction unit

18

spring element

20

bow spring

22

reception area

24

recess

26

Parked edge

27

recess

28

First edge

29

Predetermined bending axis

30

Second edge

32

leg

34

leg

36

plug-in end

38

plug-in end

40

centerpiece

42

wing

44

wing

46

web

48

web

50

hole

52

hole

Claims (7)

1. Hob apparatus with a heating element support unit (10), which is provided for retaining at least one heating element, wherein the heating element support unit (10) has at least one region (12) with at least one desired bending point (14), characterised in that the hob apparatus has a force reducing unit (16) which is provided to lower a torque acting on the desired bending point (14) of the heating element support unit (10) during a mechanical load, wherein the force reducing unit (16) has at least one spring element (18), and wherein the spring element (18) extends beyond the desired bending point (14).
2. Hob apparatus according to claim 1, characterised in that the spring element (18) is formed by a bow spring (20).
3. Hob apparatus according to one of the preceding claims, characterised in that the spring element (18) has a pretensioning in an installed state.
4. Hob apparatus according to one of the preceding claims, characterised in that the heating element support unit (10) has a concave receiving region (22) for the at least one heating element and the spring element (18) is arranged at least partially in the receiving region (22).
5. Hob apparatus according to one of the preceding claims, characterised in that the heating element support unit (10) has at least one recess (24) at least partially inducing an increased pliability in a subregion of the desired bending point (14).
6. Hob apparatus according to claim 5, characterised in that the heating element support unit (10) has at least one offset edge (26), in which the at least one recess (24) is arranged.
7. Hob, in particular induction hob, with a hob apparatus according to one of the preceding claims.

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