EP0070042B1 - Electric cooking plate - Google Patents

Description

The invention relates to a method for producing an electric hotplate, which has a hotplate body with heating elements and with a lower cover plate and an insulating piece protruding through the cover plate for receiving heating element connecting lines, the heating element connecting lines being electrically and on the outside of the hotplate arranged heat-resistant insulated free ending and are intended for the connection of mains power supply lines for the hotplate to be carried out when installing the hotplate for connection to a connector.

For hot plates it is e.g. B. from US-A-1 093 754 known to provide an insulating piece to lead out the connecting lines directly connected to the heating elements on the underside of the hotplate, from which the connecting lines protrude freely ending. When the hotplate is installed, its connecting lines are then connected in an electrically conductive manner to the mains power supply lines installed at the installation site, for which purpose a suitable connecting piece is generally used. The attachment of the connecting piece at the installation site or during the installation of the hotplate is relatively unwieldy and, especially with hotplates to be connected with more than two poles, has the essential disadvantage that incorrect connections can easily be caused. Furthermore, the individual lines protruding from the hotplate are bulky due to their bulkiness, both during storage and during transport and when installing the hotplate.

From DE-A-2 651 848 it is also known to structurally integrate a connector with the hotplate body in such a way that the connector protrudes outward over the circumference in a plan view of the hotplate and is therefore accessible for attaching the mains power supply lines . This immovable or rigidly attached to the hotplate connector, which in and of itself facilitates the correct connection of the hotplate to the mains power supply lines, is a hindrance both for storage and transportation of the hotplate and, above all, makes it difficult to insert the hotplate into the associated installation opening of a hob or the like, which is why such an arrangement could not always satisfy.

The invention has for its object to provide a method for producing an electric hotplate and an electric hotplate produced by this method, which ensure simplified installation of the electric hotplate with improved storage and transport options.

To solve this problem is provided according to the invention in a method of the type described in the introduction that the connector is attached to the heating element connecting lines during the production of the hotplate in such a way that they are combined into a flexible band consisting of individual lines lying next to one another, which at a Swiveling about a transverse axis lying parallel to the plane of the belt is more flexible than swiveling about other axes and that the heating element connecting piece is movable relative to the hotplate between an installation position for installing the hotplate and a connection position outside the hotplate due to the sufficient length of the heating element connecting lines remains. As a result, several problems that arise with regard to the storage, transport and installation of electric hotplates are solved in a surprisingly simple manner. The heating element connecting lines are already connected in the correct order from the time the hotplate is manufactured to the connection piece integrated with the hotplate into a prefabricated assembly, which generally has markings for the correct connection of the mains power supply lines and that there is a risk of incorrect connection of these supply lines significantly reduced. Since the connector still remains movable with respect to the hotplate body, it can be brought into a suitable position for storage, transport, installation and electrical connection, which considerably simplifies the handling of the electric hotplate from manufacture to final installation. The relatively easy pivoting in one level means that the connector can be folded inwards, which is particularly advantageous during the installation of the hotplate in the stove.

An electric hotplate according to the invention is specified in independent claim 2.

A particularly advantageous feature of this subject matter of the invention is that in the lower cover plate of the electric hotplate there is a depression which is directed toward the interior of the electric hotplate and is designed to accommodate the connecting piece. This results in the possibility of accommodating the connector during storage and possibly during transport and also during the installation of the hotplate in a particularly space-saving manner or almost sunk into the cover plate, as a result of which the connector does not increase the stacking height of hotplates stacked one on top of the other. According to the invention, the depression can lie in the region of the insulating piece, so that it can accommodate not only the insulating piece of one cooking plate but also the connecting piece of the other cooking plate when the hotplates are stacked together with their undersides.

• Figur 1 einen Querschnitt durch eine in einen Elektroherd, eine Kochmulde o. dgl. eingebaute Elektro-Kochplatte,
• Figur 2 drei übereinandergestapelte Kochplatten, die bis auf den Erdungsanschluß derjenigen nach Fig. 1 entsprechen und die zugehörigen Verpackungsmittel,
• Figur 3 die Hinteransicht einer Kochplatte.

Further advantages and features of the invention emerge from the description in connection with the drawings. Execution Games of the invention are shown in the drawing and are explained in more detail below. Show it :

• FIG. 1 shows a cross section through an electric hotplate built into an electric cooker, a hob or the like,
• 2 shows three hotplates stacked one on top of the other, which correspond to those of FIG. 1 except for the ground connection and the associated packaging means,
• Figure 3 is the rear view of a hot plate.

In Fig. 1, an electric hotplate 11 is shown, which has a hotplate body 12 made of cast iron with an upper flat and closed cooking surface 13. The unheated central zone 14 is lowered, so that an annular cooking surface 13 is formed. The hotplate body 12 overlaps on its outer circumference via an overhang edge 15 made of sheet material of essentially U-shaped cross section, which is supported on the raised opening edge 16 of the worktop 17 of an electric cooker or hob.

In the heated ring area, the hotplate 11 is provided with spirally extending ribs, which likewise form spiral grooves 18, in which heating elements 19 in the form of heating coils lie in a ceramic investment material 20.

In the peripheral area of the hotplate body 12 there is a downwardly directed, essentially cylindrical edge 21, on the lower edge 22 of which a flange-like edge area 23 of a cylindrical cover plate 24, which is stiffened and deformed by features, is supported. At the edge region 23 there is an upward, ie. H. to the cooking surface 13 towards step 25, which rests on the inside of the edge 21 and thus centers the end cover or the cover plate 24.

At one point on the circumference, the edge 21 has a recess 26 in the form of a square cutout, into which a corresponding design 27 of the cover plate is placed and thus ensures that the cover plate 24 is secured against rotation on the hotplate body 12 despite a relatively tight seal. The shape 27 of the cover plate 24 in turn ensures that the finished hotplate 11 can be aligned in the circumferential direction during its handling during manufacture. As a result, no inner projection is necessary at the edge 21. The step 25 is followed by an area 28 of the cover plate 24 which springs back relative to the edge area 23 and is adjoined by a central area 29 which projects somewhat from the edge area 23. With regard to the design in detail, reference is also made to EP-B1-0 024 621.

In the center of the unheated central zone 14, the hotplate body 12 has a downwardly projecting pin 30, into which a blind hole 31 projects. A hollow cap screw 32 is screwed into this threaded bore 31 and protrudes through a central hole in the cover plate 24, so that the cover plate 24 is pressed with its edge region 23 against the lower edge 22 of the edge 21 of the hotplate body 12. Between the head of the cap screw 32 and the cover plate 24, a sheet metal part 37 is interposed, which includes a ground line with a bent end 39. It is particularly advantageous that the sheet metal part 37 lies flat against the underside of the cover plate 24 during manufacture and shipping and is only bent off from it if necessary. The earth connection therefore does not significantly increase the height of the hotplate.

After installation, the hotplate 11 is held in the worktop opening receiving it by a bracket 42 which is supported on the underside of the worktop 17, has a flat U-shape or has a pin 47 which engages in a recess 46 in the cover plate 24 to prevent rotation. Its long back is stiffened by side bends 43. A screw 45, which is screwed into the internal thread in the hollow cap screw 32, projects through a hole 44 in the middle of the bow. Thus, the hotplate 11 is clamped down by the screw 45 and the bracket 42 and is securely fixed.

In order to enable several installation positions for the hotplate 11, which is particularly important because of the position of the supply lines 78 to be connected, a plurality of depressions 46 can be provided on one circumference, possibly also offset by 90 ° from one another.

From Fig. 1 it can be seen that a metal foil 51 is located approximately parallel to the cover plate 24 in the interior 48, which is in particular a bare aluminum wrinkle film. It is clamped between the edge 21 and the cover plate 24 and includes a layer 52 between itself and the cover plate 24, which preferably consists of or contains silica gel or diatomaceous earth. This material not only provides good insulation, but also acts as a drying agent. If extreme conditions with regard to the occurrence of moisture are not to be feared, it is possible to produce the layer 52 from highly heat-resistant insulating materials, for example inorganic fibers such as asbestos or other known insulating materials. Together with the overlying metal foil, a very effective insulation is formed, which further reduces the heat losses due to radiation and convection downwards, which are already low in a contact hotplate. However, this primarily keeps the temperature of the cover plate 24 low, so that it can be installed even in the flattest cooktops near wooden parts in kitchen furniture.

2 shows three hotplates 11 stacked one on top of the other, which are the same as the hotplate 11 according to FIG. In the description, the same reference numerals are used same parts. The cut is offset by 45 ° in FIG. 2 compared to FIG. 1.

It can be seen that through the cover plate 24 protrudes on the inside of this supporting insulating piece 55, which contains a temperature limiter in its interior section and has through openings 57 (Fig. 3), through which a highly heat-resistant insulation provided connection lines 58 protrude from the interior 48, where they are welded to connecting pins of the heating elements which protrude from the investment material 20. The basic shape of the insulating piece 55 is elongated in the circumferential direction and it projects through the cover plate 24 in the region of a bulge 60.

The connecting lines 58 are connected to a common connecting piece 75 made of ceramic insulating material, which contains plug or screw connection terminals 76 for connecting the mains power supply lines 78. Due to the arrangement of the insulating piece 55 in the radial direction approximately in the middle of the annular heated area or in the range between 2/3 to 3/4 of the hotplate radius from the hotplate center, and by the dimensioning of the length of the connecting lines 58, the free end edge lies 77 of the connector 75 preferably at a maximum distance of less than a hotplate radius from the outer edge of the hotplate 11 and can be flexibly adapted to the installation conditions. The adjacent connecting lines 58 act like a flexible band, which allows easy pivoting and greater mobility of the connecting piece 75 in the vertical direction, but more restricting twisting and lateral movement.

The insulating piece 55 diametrically opposite and at a corresponding radial distance from the hotplate center there is a recess 61 in the cover plate 24, which is selected in its dimensions so that it the projecting part of the insulating piece 55 in the mutual assignment of the hotplates 11 shown in FIG. 2 can record with certainty without the leads 58 being kinked too sharply. The width of the recess 61 is substantially larger than that of the insulating piece 55, so that, as can be seen from FIG. 2 for the two upper hot plates 11, the connecting lines 58 can be folded inwards and the connecting piece 75 next to the insulating piece 55 in the Well 61 can lie. It is also possible to store the connecting piece 75 (FIG. 2 below) folded outward in approximately one plane with the hotplate 11, the connecting lines 58 leading through a corresponding cutout in a packing plate 63.

The recess 61 in the cover plate 24 makes it possible to pack the hot plates 11 particularly safely and in a space-saving manner during storage and shipping. For this purpose, the hot plates 11 are stacked with their central axes aligned with one another, with their flat cooking surfaces 13 and with their undersides covered by the cover plates 24, with only one sheet or film 62 being inserted between the cooking surfaces 13 to prevent scratches, while between them Hotplate undersides a packing plate 63 is placed, which can consist of plywood or chipboard and has recesses 64 which are selected so that the hotplate is centered on it when placed on it. Parts of the hotplate 11 projecting downward from the edge area 23 of the cover plate 24 protrude into the recess 64 of the packing plate 63.

The hot plates 11 are each offset by 180 ° in the circumferential direction, so that the insulating piece 55 with the connecting lines 58 projects into the recess 61 and the hot plate 11 even requires a smaller packing space than its total height. The edges 21 are supported against one another with the interposition of the packing plate 63, so that a solid stack is formed which does not tend to tip over. The aligned arrangement of the hot plates 11 also contributes to this. The packing plates 63 have numerous recesses 64 side by side and one behind the other in accordance with the desired packaging or plate size, so that a large number of hot plates 11 can be stored and transported in a solid block. This not only saves storage and transport costs, it also increases accident safety. Packing can also be done fully automatically using grippers. 2 is missing the silica gel filling. An aluminum wrinkle film 51 is placed parallel to the cover plate 24 only for insulation purposes.

Since the hot plates 11 are preferably packed in a position offset by 180 °, the depression 61 is diametrically opposite the insulating part 55. It would also be conceivable to provide an offset at a different angle. Accordingly, the recess 61 would also have to be offset from the insulating piece 55 by a different angle. In any case, the end plate 24 has the advantage that it is easy to manufacture despite sufficient rigidity due to the not very deep deformation and creates a well-insulated closed interior. In the case of an embodiment with a central opening for a central sensor socket, the cover plate could be placed against the edge 21 as well as against an inner edge surrounding the central opening with one shoulder of the cover plate. The fastening could also be done there using banjo bolts. In this case, the hollow cap screw would not be located centrally, but in the area of the edge, for example.

A further arrangement can be seen from FIG. 3 in order to ensure that the hotplate 11 is secured against rotation with respect to fastening parts, for example the bracket 42. For this purpose, a sheet metal part 65 is used, which has the shape of a flat, wY, stripy strip and whose leg ends are bent or rolled up so that these Ends are pin-like. The sheet metal part 65, like the sheet metal part 37 in FIG. 1, is fastened to the hotplate body with the hollow cap screw 32 and secured there against rotation. The leg ends of the sheet metal part 65 are preferably only bent by approximately 90 ° when the hotplate 11 is installed in a stove or the like. Only the leg end that is to be inserted into a hole in the mounting bracket 42 needs to be bent.

Claims (2)

1. Method for the manufacture of an electric cooking plate (11) having a cooking plate body (12) with heating elements (19) and with a lower sheet cover (24), together with an insulating piece (55) projecting through the sheet cover for receiving heating element connecting lines (58), the latter being arranged in freely terminating electrically and heat-resistantly insulating manner in the outside of the cooking plate and are intended for the connection of mains current supply lined for the hot plate for connecting to a connecting piece (75) to be carried out on fitting the cooking plate, characterized in that during the manufacture of cooking plate (11), connecting piece (75) is so fitted to the heating elements connecting lines (58) that they are combined into a flexible band comprising juxtaposed individual lines (58) which on pivoting about a transverse axis parallel to the plane of the band is more flexible than on pivoting around other axes and that, due to the adequate length of the heating element connecting lines (58), the heating element connecting piece remains movable with respect to cooking plate (11) between a fitting position for fitting the cooking plate (11) and a connecting position outside cooking plate (11).

2. Electric cooking plate (11) with a cooking plate body (12) and a lower sheet cover (24), as well as an insulating piece projecting through said sheet cover for receiving outwardly directed electric heater connecting lines (58), which are electrically insulated in heat-resistant manner and flexible, characterized in that the connecting lines (58) are combined by their ends with a common connecting piece (75) freely movable therewith to give a flexible line band comprising juxtaposed individual lines and which on pivoting about an axis (located parallel to the cooking surface (13) of cooking plate (11) is more flexible than on pivoting about other axes, that the connecting lines (58) are sufficiently long to permit the positioning of connecting piece (75) outside the region of the electric cooking plate (11) and that in the sheet cover (24) is provided a recess (61) directed towards the interior of cooking plate (11) and which is constructed for receiving connecting piece (75).

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