HOT PLATE, AND HOB HAVING A HOT PLATE

Abstract

A hot plate has a hot-plate body from metal, having an upper side and a lower side. At least one heating element is disposed on the lower side of the hot-plate body. The upper side of the hot-plate body is configured so as to be flat, for setting up a cooking vessel to be heated. The upper side of the hot-plate body in an external region has an encircling planar region which lies in a plane, or which forms a plane, respectively, wherein the upper side, radially within the planar region, has at least one internal region which is concavely depressed, which in relation to the planar region is depressed by between 0.05 mm and 1 mm.

Claims

1. A hot plate comprising: a hot-plate body, wherein: said hot-plate body has an upper side and a lower side; said hot-plate body is composed of metal; at least one heating element is disposed on said lower side of said hot-plate body; said upper side of said hot-plate body is configured so as to be flat, for setting up a cooking vessel to be heated; said upper side of said hot-plate body comprises an external region in which an encircling planar region is provided, said encircling planar region lying in a plane or forming a plane, respectively; and said upper side, radially within said planar region, comprises at least one internal region being concavely depressed.

2. The hot plate according to claim 1, wherein said hot-plate body is composed of cast iron.

3. The hot plate according to claim 1, wherein said planar region is spaced apart from an external edge of said hot plate having a maximum radial extent by a maximum of 5% of a radius of said hot-plate body, wherein only an oblique and sharply downward chamfered hot-plate periphery, radially outside said planar region, encircles said planar region.

4. The hot plate according to claim 1, wherein said encircling planar region comprises a width of 1 mm to 30 mm.

5. The hot plate according to claim 1, wherein said encircling planar region comprises a width of 3 mm to 10 mm. 6. The hot plate according to claim 1, wherein said encircling planar region comprises a width between 1% and 20% of a radius of said hot-plate body.

7. The hot plate according to claim 6, wherein said encircling planar region comprises a width between 3% and 10% of a radius of said hot-plate body.

8. The hot plate according to claim 1, wherein said encircling planar region comprises a consistent width.

9. The hot plate according to claim 1, wherein said internal region is concavely depressed, said concavity comprising a shape or curvature, respectively, of a cone or of an arc.

10. The hot plate according to claim 9, wherein said internal region comprises a single concave depression.

11. The hot plate according to claim 10, wherein a maximum depth of said concave depression below said encircling planar region is 0.05 mm to 1 mm.

12. The hot plate according to claim 9, wherein, in a central region of said internal region, a central zone that in relation to said concave depression is yet again depressed and that comprises a depth between 0.3 mm to 3 mm below said encircling planar region is provided.

13. The hot plate according to claim 12, wherein a maximum depth of said concave depression of said internal region below said encircling planar region is 0.05 mm to 1 mm.

14. The hot plate according to claim 13, wherein said depressed central zone is concavely curved, having a more intense curvature than a curvature of said internal region.

15. The hot plate according to claim 12, wherein no heating elements are provided below or opposite said depressed central zone, respectively, on a lower side of said hot plate.

16. A hob having at least one hot plate according to claim 1, wherein: said hob comprises a hob plate comprising a hot-plate opening in said hob plate into which said hot plate is inserted, said hot plate by way of a laterally projecting periphery of said upper side of said hot-plate body projecting beyond said hot-plate opening, wherein for fastening said hot plate to said hob, a counterbearing is attached to said hot plate from below and in a central region is fastened or screwed to said hot plate; and said counterbearing engages across said hot-plate opening and bears on said lower side of said hob plate at least three bearing points, said bearing points being mutually spaced apart by an arc angle of at least 45°.

17. The hob according to claim 16, wherein said counterbearing is configured so as to be cruciform, comprising at least three arms that emanate from a center.

18. The hob according to claim 17, wherein said arms are mutually equiangular.

19. The hob according to claim 16, wherein said counterbearing comprises a shape of a curved disc and a central region, wherein said counterbearing in said central area is connected to said hot plate, and in an external region largely bears on said lower side of said hob plate.

20. The hob according to claim 19, wherein said counterbearing comprises an opening for an electrical connector to said hot plate.

21. The hob according to claim 16, wherein said hob comprises a hob plate from metal or stainless steel, respectively.

22. A hob comprising: at least one hot plate comprising a hot-plate body, wherein: said hot-plate body comprises an upper side and a lower side; said hot-plate body is composed of metal; at least one heating element is disposed on said lower side of said hot-plate body; said upper side of said hot-plate body is configured so as to be flat, for setting up a cooking vessel to be heated; said hob comprises a hob plate comprising a hot-plate opening into which said hot plate is inserted; said hot plate by way of a laterally projecting periphery of said upper side of said hot-plate body projecting beyond said hot-plate opening; for fastening said hot plate to said hob, a counterbearing is attached to said hot plate from below and is centrically fastened or screwed to said hot plate; said counterbearing engages across said hot-plate opening and bears on said lower side of said hob plate at least three bearing points; and said bearing points being mutually spaced apart by an arc angle of at least 45°.

23. The hob according to claim 22, wherein said counterbearing comprises a shape of a curved disc, and in a central region is connected to said hot plate, and in an external region largely bears on the lower side of the hob plate.

24. The hob according to claim 23, wherein said counterbearing in said external region in a completely encircling manner bears on said lower side of said hob plate.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0027] Further advantages and aspects of the invention are derived from the claims and from the description hereunder of various preferred exemplary embodiments of the invention that are explained hereunder by means of the schematic figures. In the drawings:

[0028] FIG. 1 shows a sectional illustration through a first design embodiment according to the invention of a hot plate having a single concavely depressed internal region within an encircling planar region.

[0029] FIG. 2 shows a further alternative design embodiment of a hot plate according to the invention, as a modification of that of FIG. 1, having an additional yet again depressed central zone.

[0030] FIG. 3 shows a hob according to the invention, having two hot plates according to the invention that are inserted into a hob plate and are held from below by counterbearings.

[0031] FIG. 4 shows a lower view of the hob of FIG. 3, having two dissimilarly configured counterbearings.

[0032] FIG. 5 shows a detailed oblique illustration of the disc-shaped counterbearing that is illustrated on the left in FIG. 4.

DETAILED DESCRIPTION

[0033] A right-hand region of a hot plate 11 according to the invention that has a hot-plate body 13 is illustrated in a section in FIG. 1. The hot-plate body 13 has a substantially flat upper side 15 which however does not inevitably have to be completely planar by any means. An encircling planar region 17 which is configured as a circular ring having a consistent width, the latter being indicated thereabove by the short lines, is provided in the external region. This width may be 10 mm. The planar region 17 is completely planar, or lies completely in one plane, or in other words does not project beyond a plane on which the planar region 17 nevertheless chiefly or largely or completely bears, respectively, or which plane the planar region 17 defines, respectively. This means that micro-depressions, a rough surface, or concentric channels that are usually created by rotating final machining of a casting of which the hot-plate body 13 is composed, having a depth of significantly less than 0.3 mm, are not considered a deviation from this planarity. The upper edges or upper sides of the channels in this instance lie substantially in the mentioned planar plane.

[0034] An internal region 19 according to the invention which lies below the planar plane of the planar region 17, or which is concavely depressed, respectively, is provided so as to be radially within the planar region 17. Herein, this depression may either be spherically concave, as has been explained at the outset, such that in a heavily enlarged lateral illustration of FIG. 1 the internal region 19 would be a segment of a circle, having the lowest point in the center. Alternatively, the internal region 19 may be concavely depressed in a conical manner, such that the flanks on the left and the right would substantially be straight lines, and would be mirror-symmetrical in relation to a central axis of the hot plate 11 that is illustrated with dashed lines. This is more readily possible by rotating machining, as has been mentioned above. In yet another further alternative design embodiment of the invention, the depressed internal region 19 may also have any other curved shape. A transition from the internal region 19 to the planar region 17 may be gradual or soft, respectively, in certain circumstances having a very slightly configured edge at the transition. The planar region 17 in the plan view has an annular-ring shape, the depressed internal region 19 having a circular shape.

[0035] The internal region 19 lies in the center in the region of the dashed-line central axis that has the greatest depth, or the deepest point, respectively, approximately 0.1 to 0.2 mm below the plane of the planar region 17. This suffices as a depression in order for the technical advantages that are achieved by the invention. A foreseeably very small air gap results towards the lower side of a set-up cooking vessel. However, the air gap is not capable of being illustrated in the drawing, even at a great enlargement, but is readily comprehensible by means of the illustration shown herein. The diameter of the hot plate herein is approximately 18 cm.

[0036] An external edge 21 of the hot-plate body 13 runs so as to be radially outside the planar region 17. A peripheral chamfer 22 is configured above this external edge 21. Thus, the planar region 17 does indeed not form the outermost region of the hot plate 11, or of the hot-plate body 13, respectively, but does at least lie very far to the outside, or there is identifiably no region that is conceived for setting up a cooking vessel to be heated radially outside thereof, respectively.

[0037] Except for the upper side 15, or the planar region 17, respectively, and for the depressed internal region 19, the hot plate 11 is configured according to the prior art. An encircling flange periphery 26 which radially lies somewhat within the external edge 21 is moulded to the outside of the lower side 15 of the hot-plate body 13. Encircling webs 28 are moulded to the lower side 25 so as to be radially within the flange periphery 26, wherein a heating helix 29 that is embedded in an insulation material runs as a heating element in the depressions that are formed on account thereof. A projecting central dome 31 having a thread 32 provided therein is configured in a centric manner about the dashed-line central axis. The central dome 31 lies somewhat below the flange periphery 26 but in certain circumstances may also protrude beyond the latter.

[0038] In the case of the further hot plate 111 according to the invention of FIG. 2, an externally encircling planar region 117 is again provided as an annular ring on an upper side 115 of a hot-plate body 113. The width of the annular ring may again be approximately 10 mm, at a diameter of the hot plate 111 of 18 cm. A depressed internal region 119 which in terms of shape and depth may be configured in a manner similar to that of the internal region 19 in the case of the hot plate 11 of FIG. 1, specifically also as an annular ring, is provided radially within the planar region 117, or in certain circumstances so as to directly adjoin the latter. The depth of the annular ring, or the lowest point thereof, in the case of a continuous profile would lie approximately 0.1 to 0.2 mm below the plane of the planar region 117. Again, this is not capable of being illustrated in the drawing; please refer to the explanations above.

[0039] A yet again depressed central zone 120 which advantageously is rotationally symmetrical or which is configured so as to be circular if and when the entire hot plate 111 is circular, is provided in a centric manner about the central axis of the hot plate 111 that is illustrated with a dashed line. The yet again depressed central zone 120 in the center may have a maximum depth of approximately 1 mm to 1.5 mm as the deepest point, this under certain circumstances being somewhat more or less. As can be seen from the sectional illustration, the yet again depressed central zone 120 does not have a very gradual transition to the radially outward and adjacent internal region 119, but drops in a relatively rapid manner to more than half the maximum depth. This means that bearing thereon by a set-up cooking vessel to be heated can definitely not be achieved herein by way of the design embodiment and the depth of the depressed central zone 120. The function of this depressed central zone 120 corresponds to that of other usual hot plates known from the prior art; in particular, the issue is the expansion behavior of the hot-plate body 113 during heating.

[0040] As can be seen, it may be provided according to a generally advantageous aspect of the invention that the yet again depressed central zone 120 in the radial direction extends only as far as heating elements (not illustrated here) would be provided on a lower side 115 between the webs 128. On account thereof, it is ensured that no heating output is discharged in the region of the central zone 120 where effectiveness would in any case be extremely minor.

[0041] A hob 35 according to the invention, having a hob plate 36 known per se, advantageously from a stainless steel sheet, is illustrated in a simplified sectional illustration in FIG. 3. Two hot-plate openings 37, advantageously of identical configuration and under certain circumstances of dissimilar diameters, into which the two hot plates 11 according to the invention are inserted, are provided in the hob plate 36. Alternatively, hot plates as known from the prior art may also be inserted. In practice, the hob plate 36 in the region of the hot-plate openings 37, as can be assumed from the lower view of FIG. 5, has a collar that is pulled upward. As is known to a person skilled in the art, this collar bears externally on the flange periphery 26, in the transition of the latter to the horizontal region of the external lower side 25 of the hot-plate body 13 towards the external edge 21. An encircling stainless-steel ring is also push-fitted over the flange periphery 26 therebetween, the stainless-steel ring in turn externally engaging across the upper end edge of the hot-plate opening 37 and bearing on the upper side of the hob plate 36. In this way, a visually appealing and potentially even tight connection protecting against contamination may be achieved. This, however, corresponds to the prior art.

[0042] A counterbearing 40 is attached from below to each hot plate 11, so as to radially engage across the latter and in particular also across the hot-plate openings 37. The counterbearing 40 then in each case bears on the lower side of the hob plate 36, outside the hot-plate opening 37. The counterbearing 40 is braced in relation to the hot plate 11 by means of a screw 43 in the aforementioned threads 32 in the central dome 31 of the hot plates 11, the counterbearing 40 pulling the hot plate 11 firmly from below against the hob plate 36. On account thereof, an unshiftable connection is achieved on the upper side of the hob 35.

[0043] It can be readily seen from the sectional illustration of FIG. 3 that in those case in which a counterbearing 40, as is the case in the prior art, is only a web or an arm, running from left to right, a specific force is exerted on the hot plate 11 or on the hot-plate body 13 that will bend the latter, in particular downward in the plane of the drawing. Even the hob plate 36 does not prevent this since ever thinner sheet-metal plates are often being used. On account thereof, a planarity of the upper side of the hot plate is compromised, in particular in the case of known hot plates as well as also in the case of a hot plate according to the invention. For this reason, the counterbearings 40 are advantageously configured according to an aspect of the invention as is illustrated in the lower view of FIG. 4, this specifically also applying to known hot plates. A first counterbearing 40a which has the shape of a curved disc, as has been described at the outset, is illustrated on the left in FIG. 4. The diameter of the disc of the counterbearing 40a is larger, for example 5 mm to 20 mm larger, than that of the hot-plate opening 37 that directly adjoins the flange periphery 26 (illustrated with dashed lines) of the hot plate 11, so to speak. The disc 40a has an opening 41a through which a connection cable 12 to an electric connector of the hot plate 11 may be routed. Details in this context will yet be described hereunder in the context of FIG. 5.

[0044] As an alternative to a planar disc-shaped counterbearing 40a, so to speak, a counterbearing may also be configured as is known in the prior art, that is to say in the manner of a web, but having at least four arms or two crossed webs, respectively. The four arms 42 or 42′, respectively, run in a crossed manner and thus bear on all four distributed bearing points on the lower side of the hob plate 36, being firmly held by the force of the screw 43. On account thereof, not quite as uniform bearing and encircling mounting as is the case in the counterbearing 40a on the left in FIG. 4 is achieved, however.

[0045] In the detailed illustration of FIG. 5 which does not require too much detailed explanation, a counterbearing 240a in the form of a disc similar to that of FIGS. 3 and 4 is illustrated in detail. The afore-described elevation of the periphery of the hob plate 36 of the hob 35 towards the hot-plate opening 37 can be clearly seen herein, the counterbearing 240a for this reason herein bearing in a depressed manner so to speak on the lower side of the hob plate 36, in a portion that adjoins the elevation in a radially inward manner. However, this is not mandatory. Centric fastening of a hot plate (not illustrated herein) which by way of the afore-described flange periphery of the hot plate lies radially within the counterbearing 240a is provided by means of a threaded bolt 243 with a nut. Furthermore, two bolts 245 that project from the lower side of the hot plate and penetrate corresponding openings in the counterbearing 240a are provided as anti-rotation protection. Above all, a connection installation 212 (not to be explained in more detail herein) for an electric connector of the hot plate 11 that penetrates an opening 241a in the counterbearing 240a can be seen.

[0046] Usually, hot plates on the lower side thereof have yet another cover feature which substantially covers the region between the flange periphery 26 and the central dome 31, from which thus an electric connector protrudes in a similar manner as illustrated in FIG. 5. Such a cover feature may also be provided in the case of the hot plates according to the invention, or in the case of the hobs according to the invention, having a fastening of the hot plates to the hob plates. Alternatively, when a disc-shaped and largely closed or covering counterbearing, respectively, according to FIG. 4 on the left and to FIG. 5, is used, such a cover feature may be dispensed with, since the hot plate in the installed state on the hob after all is at the latest covered by the disc-shaped counterbearing.