GB2143030A

GB2143030A - Cooker hob

Info

Publication number: GB2143030A
Application number: GB08417114A
Authority: GB
Inventors: Henry Schroder; Wilhelm Neuhauser; Rainer Haberlander
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-07-08
Filing date: 1984-07-05
Publication date: 1985-01-30
Also published as: PT78849A; NL8402097A; IT1174232B; ES292952Y; ES292952U; SE8403551L; NO842752L; FR2548765A1; DE3324783A1; PT78849B; SE8403551D0; ES289155Y; IT8421740A0; ES289155U; GB2143030B; IT8422473V0; GB8417114D0

Abstract

A cooker hob comprises a hob plate (1) which is provided with at least one opening (5) into which an electrical hotplate (2) is inserted. The hotplate rests on the rim (7) of the opening, preferably by way of a carrier ring (16), and is connected at its underside through releasable fastening means with a support element. For the formation of the opening (5), the hob plate (1) has a pot-shaped recess (6) into which the hotplate (2) is inserted and tightened to support elements arranged at a base flange (9) of the recess. <IMAGE>

Description

SPECIFICATION Cooker hob The present invention relates to a cooker hob.

In known cooker hobs with electrical hotplates, especially solid hotplates (DE-OS 29 33 350), inserted into openings in the hob plate, the hotplate is constructed as a cast part and is connected firmly with the hob plate in such a manner that underneath the hotplate or all the hotplates a respective or a common trough-like support plate is arranged, to which the or each hotplate is attached by, for example, threaded bolts and which bears against the upper hob plate. In this case, the support plate serves as a counterbearing for the fastening element. The hotplate itself rests at its outer periphery which is formed in the manner of a flange, on a substantially U-section carrier ring which in turn bears against the rim of the afore-mentioned opening in the hob plate.DE-PS 25 55560 shows a similar construction, in which the lower support plate has saucer-like stamped portions in the region of the hotplates and is secured by threaded bolts to the hotplates in the middle region of these stamped portions.

In all these known constructions, a relatively large number of individual parts are required, which makes production and assembly more difficult and expensive. Moreover, the parts serving for the fastening of the hotplates must be constructed to be very rigid in order to ensure firm seating of the hotplate and particularly a good sealing between the upper hotplate rim and the hob plate. A problem in this case is that for reasons of weight-saving, the lower support plate is usually made of relatively thin sheet metal which then yields during the tightening of the fastening element so that the contact pressure is reduced.

There is thus scope to so improve cooker hobs that the effort in terms of production and assembly is reduced and a firmer seating of the hotplates in the hob plate is obtained.

According to the present invention there is provided a cooker hob comprising a hob plate provided with a substantially pot-shaped recess, and an electrical hotplate which is inserted into the recess to be supported by way of a rim portion of the hob plate around the recess and which is releasably secured at its underside to locating means at the base of the recess.

Due to the pot-shaped recess, or several such recesses, in the hob plate, the rigidity of the parts serving for the fastening may be substantially increased in the region in which the hotplate is to be connected firmly with the hob plate. The recess serves for reception of the hotplate as well as a supporting or fastening parttherefor, and even when a relatively thin sheet metal material is used for the hob plate, a relatively high rigidity and compressive strength is obtained at the location of the recess. As a result, it may be possible to tighten the hotplate in the recess with increased compressive force relative to the hob plate without risk of a deformation. By this means as well, an improved sealing at the rim of the hotplate is obtained.

Through such a pot-shaped recess, the advantage may be obtained that further functional elements, such as elements to secure against rotation or the like, can be formed at the recess so that special components for these purposes are not needed.

There is also the advantage that the elements provided for fastening are disposed in a position which is convenient in terms of assembly procedures, and special connecting support elements between the plane of the hotplate base and the plane of the hob plate may be redundant. All such recesses in a hob plate can be formed, in economical manner, in one deep-drawing operation.

Preferably, the recess is defined by an annular wall substantially perpendicular to the general plane of the hob plate and by an annular flange projecting substantially radially from the annular wall. This provides a very rigid and pressure-resistant structure of the recess, wherein the locating means or support elements, i.e. the parts at which a connection takes place between hotplate and hob plate, lie in a region of the recess of stable shape, namely directly in the region or in the proximity of a bending location so that deformation is unlikely even in the case of very firm mounting of the hotplate.

For preference, the rim portion is provided by an annular shoulder which projects upwardly from a general plane of the hob plate. Through this measure, inter alia, the rigidity at the transition from the hob plate plane to the recess is increased substantially. In known manner, this annular shoulder can serve as a bearing for a carrier ring, on which the hotplate bears directly by a rim flange.

Preferably, the locating means comprises a member arranged underneath the base of the recess and connected with the hob plate to be secure against rotation relative thereto, and a fastening element fastening the hotplate to the member. The hob plate may be provided at the base of the recess with a plurality of tongues engaged in a corresponding plurality of openings in the member thereby to secure the member and the hob plate against relative rotation. Additionally, the member can be provided with at least two tongues each engaged in a respective opening in the base of the hotplate thereby to secure the member and the hotplate against relative rotation.

Since the diametral spacing between the oppositely disposed support places at the base part of the recess is relatively small, no great rigidity is required for the, for example rail-shaped, member. The member is preferably so constructed that it can be employed universally for different sizes of hotplate.

Preferably, the tongues are hook-like bent lobes or the like, which automatically engage into corresponding openings or recesses of the respective other part on assembly of the hob plate and hotplate.

In further advantageous embodiments, the preferably annular base part of the recess serves directly as a supporting or tightening partforthe hotplate, without additional carrying parts, such as rails or the like, being necessary.

Preferably, the hotplate is associated with a potlike cover which is firmly connected with a heating element body of the hotplate, for example through pressing over of detent lugs or the like, before final assembly of the cooker hob and is inserted together with the element body into the recess of the hob plate. In this case, the support element or support points necessary for fastening to the hob plate are disposed at this cover so that no particular constructional measures are required for this at the heater element body, which may be a cast part.

It is also advantageous if the annular base part of the recess has an upwardly extending inward rim, which, in the case of any leakage, forms a water trap.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a partly sectional elevation of part of a first cooker hob embodying the invention; Figure 2 is a partly sectional elevation of part of a second cooker hob embodying the invention; Figure 3 is a plan view, in the direction Y of Figure 2, of part of the cooker hob of Figure 2; Figure 4 is a plan view of the cooker hob of Figure 2 with hotplates removed; Figure 5 is a partly sectional elevation of part of a third cooker hob embodying the invention; Figure 6 is a view, to an enlarged scale, of the detail Z of Figure 5; Figure 7 is an inverted plan view, in the direction X of Figure 5, of a hotplate of the hob of Figure 5; and Figure 8 is a sectional elevation of part of a fourth cooker hob embodying the invention.

Referring now to the drawings, there is shown in Figure 1 part of a cooker hob comprising a hob plate 1, which is produced of relatively thin sheet metal, for example sheet steel, and which supports a plurality of, for example four, solid electrical hotplates, one such hotplate being designated by 2. This hotplate consists of an upper cast part with a rim flange 3 and a lower cover 4, which is firmly connected with the cast part. The hob plate 1 has a circular opening 5 receiving the hotplate 2, the opening being formed by a pot-shaped recess 6 which is produced by the deep-drawing method and commences from a profiled annular shoulder 7 projecting upwardly of a general plane of the hob plate, the shoulder comprising two step-shaped portions 7' and 7".The recess 6 is defined by an annular wall 8, which extends perpendicularly to the general plane of the hob plate, and an annular flange 9 which extends perpendicularly to the wall 8. At least two diametrally opposite hook-like or strap-like, downwardly bent tongues 10 are formed on the free inside rim of the flange 9. Placed from below against the flange 9 is a locating element 11, which is constructed as a U-rail and which is provided on either side of the hotplate axis band at different spacings with openings 12, into two of which the tongues 10 engage and thereby serve as support elements and simultaneously as elements to secure against rotation.The spacings ofthe openings 12 are selected so that the same element 11 can be employed for different hotplate sizes and for recesses of correspondingly different widths, i.e. the spacing between associated openings corresponds to the diameter of a respective size of hotplate.

Formed on the element 11 or bent out from the limbs thereof are two hook-like or strap-like tongues 13 which, when the hotplate 2 is assembled, engage in corresponding openings 14 in the hotplate base 15 or in the base of a corresponding cover of the hotplate and thereby prevent rotation of the hotplate 2 relative to the hob plate 1. The rim flange 3 of the hotplate 3 bears on a substantially U-section carrier ring 16, the inner limb of which is pressed against the slightly conical external circumference of the hotplate 2 and the outer limb of which bears on the shoulder portion 7'. The hotplate 2 is centred relative to the somewhat wider recess 6 by the tongues securing against rotation or by centring portions 17 bent out of the wall 8 to project into the opening 5 in the region of the flange 9.Serving to tighten the hotplate 2 to the hob late 1, i.e. to the flange 9, is a threaded bolt 18, which extends along the hotplate axis b and is fastened to the hotplate or the cover thereof, the bolt engaging through a corresponding opening in the element 11 and enabling tightening of the hotplate relative to the element 11 by means of a nut 19. The dimension a between the tongues 13 remains the same for a!l hotplate sizes.

In the embodiment according to Figures 2 to 4, an electrical hotplate, again designated by 2, is connected with a carrier ring 16 and is mounted in a recess 6' in a hob plate 1', the recess 6' being slightly changed compared with the recess 6 in Figure 1. The recess 6' also possesses an annular flange 9', which has a slightly upwardly drawn inner rim 20. Figure 4 is a plan view of the hob plate 1' from above without the hotplates 2. The circular openings 5 for the hotplates 2 as well as three uniformly distributed openings 21 in each flange 9 are clearly apparent.

The hotplate 2 has threaded bushes 22 placed on, or threaded portions situated in, the underside of the hotplate 2 or the cover 4 thereof, whereby fastening of the hotplate 2 to the hob plate 1' can take place by means of screws 23. By tightening of the screw 23, the rim flange 3 of the hotplate 2 is firmly pressed against the ring 16 and thereby tightened to the hob plate 1'. The screws 23 can at the same time serve as support points for earth lines 24 (Figure 2) and furthermore as elements to prevent the hotplate 2 from being unintentionally rotated relative to the hob plate 1'. Figure 3 shows the region of the recess 6' to an enlarged scale and in viewing direction according to arrow Y. Illustrated in this case is an electrical connecting element 25 for electrical connection of the hotplate 2, the element 25 being arranged and fastened underneath the flange 9'.

In the embodiment according to Figures 5to 7, the hob plate 1' is constructed as in the embodiment of Figures 2 to 4, i.e. it has a recess 6' with an upwardly extending inner rim 20 in the region of the annular flange 9'. The enlarged view of Figure 6 shows this clearly. Three openings 21 are again provided for screws 23 in the region of the flange 9'. A pot-shaped cover 26, which is illustrated in Figure 7 as a detail with viewing direction X according to Figure 5, is provided for the hotplate 2', in particular a heating element body thereof constructed as a cast part. The hotplate 2' has a rim flange 3', adjoined by a slightly conical downwardly extending collar 27 in which an annular groove 28 is machined or formed.In this case, the rim of the cover 26 is constructed as a carrier ring 26', which is bent into U-section and in the assembled state bears on the annular shoulder of the hob plate 1'. The wall 26" of the cover 26, constructed as a drawn part, is pushed with a press fit over the outer surface of the collar 27. A firm connection between the cover 26 and hotplate 2' is produced by means of individual detent lugs or a single annular lug 29 at the cover 26, in that the lug 29 engages in the groove 28 or is pressed or rolled by a tool into this groove. The unit of hotplate 2' or heater element body and cover 26 is inserted into the recess 6' and firmly mounted to the hob plate 1' by means of screws 23 engaged in corresponding threaded portions 30 of the cover 26.As shown in Figure 7 in particular, the cover 26 has a disc-shaped central metal part integrally connected through radial ray-shaped webs 32 with the cover wall 26".

Disposed in the centre of the part 31 is an opening for a threaded bolt 18, which is fastened to the hotplate and through which an additional connection between the hotplate 2' or heater element body and cover 26 can be effected by means of a nut 19. In this embodiment, the hotplate or the cover 26 thereof bears directly on the rim 20. As shown in Figure 6, insulated heating conductors 33 are arranged in a spirally extending groove in the interior, formed by the collar 27, of the hotplate 2'.

As forthe embodiment according to Figures 5to 7, the recess 6' in the embodiment of Figure 8 has an upwardly extending inner rim 20. In the region of the flange 9', three openings 21 are again provided for screws 23. Provided for the hotplate 2", in particular a cast heater body, is a pot-shaped cover 26", which in line with the openings 21 has threaded bores 30'.

The cover 26" is inserted into the inner recess of the hot-plate 2" formed by the annular collar 27'. The cover 26" has a detent element 29', which, on assembly of the hotplate 2" and the cover 26", detents in a groove-like counter-detent element 28' at the inner circumference of the collar 27'. Such an interlocking connection can also be produced through rolling of the wall of the cover 26". Separately from this cover 26", a carrier ring 16 is arranged at the upper part of the recess 6', on which ring the hotplate 2" bears in the aforedescribed manner. After assembly of the hotplate 2", the base flange 9' of the recess 6' is secured to the cover 26" by means of the screws 23.

Claims

1. A cooker hob comprising a hob plate provided with a substantially pot-shaped recess, and an electrical hotplate which is inserted into the recess to be supported by way of a rim portion of the hob plate around the recess and which is releasably secured at its underside to locating means at the base of the recess.

2. A cooker hob as claimed in claim 1, comprising a carrier ring supporting the hotplate on the hob plate rim portion.

3. A cooker hob as claimed in either claim 1 or claim 2, wherein the recess is defined by an annular wall substantially perpendicular to the general plane of the hob plate and by an annular flange projecting substantially radially from the annular wall.

4. A cooker hob as claimed in any one of the preceding claims, wherein the rim portion is provided by an annular shoulder which projects upwardly from a general plane of the hob plate.

5. A cooker hob as claimed in claim 4when appended to claim 2, wherein the shoulder comprises stepped shoulder portions and supports the carrier ring.

6. A cooker hob as claimed in any one of the preceding claims, the locating means comprising at least one of means to centre the hotplate and means to secure the hotplate against rotation.

7. A cooker hob as claimed in claim 6, the locating means comprising a member arranged underneath the base of the recess and connected with the hob plate to be secure against rotation relative thereto, and a fastening element fastening the hotplate to the member.

8. A cooker hob as claimed in claim 7, wherein the member is a rail.

9. A cooker hob as claimed in either claim 7 or claim 8, wherein the hob plate is provided at the base of the recess with a plurality of tongues engaged in a corresponding plurality of openings in the member thereby to secure the member and the hob plate against relative rotation.

10. A cooker hob as claimed in claim 9, wherein the member is provided with a further plurality of openings usable to receive differently spaced tongues associated with a different size of recess.

11. A cooker hob as claimed in any one of the preceding claims, wherein the member is connected with the hotplate to be secure against rotation relative thereto.

12. A cooker hob as claimed in claim 11, wherein the member is provided with at least two tongues each engaged in a respective opening in the base of the hotplate thereby to secure the member and the hotplate against relative rotation.

13. A cooker hob as claimed in any one of claims 1 to 6, the locating means comprising at least two spaced apart threaded fastening elements each extending through a respective opening in an annular flange at the base of the recess and threadedly engaged in a respective threaded opening in the hotplate.

14. A cooker hob as claimed in claim 13, wherein the threaded openings are provided in bushes at the base of the hotplate.

15. A cooker hob as claimed in any one of claims 1 to 6, wherein the hotplate comprises a heating element body and a pot-shaped casing surrounding the element body and firmly connected thereto, the rim of the casing defining a U-section carrier ring supporting the hotplate on the hob plate rim portion and the locating means comprising releasable fastening elements fastening the casing to a portion of the hob plate at the base of the recess.

16. A cooker hob as claimed in claim 15, wherein the casing is connected to the element body by detent means arranged at the circumferential wall of the casing and engaging complementary detent means at the perimeter of the element body.

17. A cooker hob as claimed in either claim 15 or claim 16, wherein the casing is connected to the element body by a threaded bolt extending along an axis of rotational symmetry of the body.

18. A cooker hob as claimed in any one of claims 15 to 17, wherein the base of the casing comprises a disc-shaped central portion integrally connected to the circumferential wall of the casing by radial webs.

19. A cooker hob as claimed in claim 3, wherein the annular flange is provided at its inner edge with an upwardly extending rim portion.

20. A cooker hob as claimed in claim 19, wherein the hotplate rests on said rim portion of the flange.

21. A cooker hob as claimed in any one of claims 1 to 6, wherein the hoplate comprises a heating element body having an annular collar, and a pot-shaped casing engaged in the collar and releasably secured to the locating means.

22. A cooker hob as claimed in claim 1, wherein the casing is connected to the collar by detent means.

23. A cooker hob substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

24. A cooker hob substantially as hereinbefore described with reference to Figures 2 to 4 of the accompanying drawings.

25. A cooker hob substantially as hereinbefore described with reference to Figures 5 to 7 of the accompanying drawings.

26. A cooker hob substantially as hereinbefore described with reference to Figure 8 of the accompanying drawings.