WO1996012388A1

WO1996012388A1 - Unit for a kitchen range

Info

Publication number: WO1996012388A1
Application number: PCT/SE1995/001186
Authority: WO
Inventors: Lennart W. Castwall; Christer C. I. Wiss
Original assignee: Ab Electrolux
Priority date: 1994-10-14
Filing date: 1995-10-13
Publication date: 1996-04-25
Also published as: AU3715095A; SE9403517D0

Abstract

A building unit intended for a domestic cooking range (28; 66) having a ceramic glass hob (30). The building element includes an insulating slab (10) having provided in its upwardly facing main side a measurement-adapted open recess (20, 22) for accommodating a corresponding heating unit (12, 16) forming part of the building element. The heating unit is comprised of a heating filament and rests on projections (50) upstanding from the bottom of the recess with a small abutment surface. The slab (10) includes at least one passage (58) for accommodating electric wires (54, 56) intended for connection to and the remote control of the heating unit (12, 16), these wires extending from each recess (24) to one of the other sides of the slab (10; 70).

Description

UNIT FOR A KITCHEN RANGE

The present invention relates to a building element for a domestic cooking range fitted with a ceramic glass hob, wherein the building element includes an insulating plate or slab which is provided in its upwardly facing main side with a measurement-adapted open recess for receiving a correspond¬ ing heating unit forming part of the building element.

When fitting heating units, such as electric heating plates, heating spirals or the like in a domestic cooking range, it is known to use separate building elements for each heating unit, see for instance U.S. Patent No. 4,371,780. Such a building element has the form of a basin made of insulating ceramic material which embraces the heating unit or units placed in the basin, and is lined externally with stabilizing sheet-metal. The building element is dimensioned in accor¬ dance with the measurements of its separate associated heating unit, which means that building elements of mutually different dimensions must be provided. Each building element is fitted separately to the undersurface of the ceramic glass hob and there secured in some appropriate way, for instance with the aid of metal bracket connections. Electric wires or cables extend from the heating unit in respective basins to a related range operating knob. The wires are drawn to the knob at least partially unprotected. The ceramic material in each building element is relatively thin and is easily damaged during transportation, although the risk of damage is reduced considerably by the protective plate on the underside of the basin. The plate forms a part of the building element when fitting said element in the range. The building elements are normally sorted and packaged in accordance with size prior to their transportation. The thin wires or filaments that may form a heating unit in a building element intended for a domestic cooking range provided with a ceramic glass hob must be well-protected with special packaging material. Different types of heating filaments are generally used in building elements of the kind intended here (see for instance U.S. Patent No. 3,833,793 and EP 0 266 115). These filaments lie with one side in direct contact with an insulating support surface. As the filaments are heated, the insulating support surface affords a certain cooling effect which reduces the speed at which the filaments are heated.

This cooling effect is particularly noticeable when using a thin sintered KANTHAL^® filament as a heating unit. A filament of this kind can be heated quickly to very high temperatures and in order to achieve the best possible performance, it is absolutely necessary that the filament environment will not give rise to undesirable cooling effects. Naturally, rapid cooling of the filament may also be desirable, for corre¬ sponding reasons, for instance when wishing to lower the temperature of the filament.

Accordingly, one object of the present invention is to provide a building element which substantially decreases the aforesaid cooling effects and which enables a heating unit to be heated and cooled rapidly. Because the heating units and the wires included in the building element are very sensitive to impact, it is also important to ensure that the building element is well-protected when transported. In accordance with the invention, this protection is afforded by virtue of the fact that the building element has a thickness which in itself constitutes a durable transporta¬ tion safeguard. The building element shall be of relatively light construction and it shall be possible to arrange the heating unit/units and electric wires well-protected in the insulating ceramic material. When transporting the new building elements, it is advantageous to position said elements in relation to one another so that heating units and wires will always be surrounded by the actual containment material. The possibility of incorporating a plurality of heating units in one single building element in accordance with the invention also facilitates the assembling of a domestic cooking range, since a building element need now only be fixed relative to the ceramic glass hob, whereas in the earlier known case it was necessary to affix perhaps four separate building elements for each heating unit.

The novel inventive building element is mainly characterized in that the heating unit consisting of a heating filament rests with a small abutment surface on a projection which is upstanding from the bottom of the recess, wherein the slab includes at least one channel which is intended to accommo¬ date electric wires which are intended for connection to the heating unit and for the remote control of said unit and which extend from each recess to one of the remaining sides of the plate.

Further features of the inventive building element will be apparent from the depending Claims.

The invention will now be described in more detail with reference to a preferred embodiment thereof and also with reference to the accompanying drawings, in which

Fig. 1 illustrates one embodiment of a novel inventive building element from above;

Fig. 2 is a sectional view of the building element shown in Fig. l taken on the line A-A, said building element being shown installed in a schematically and only partially indicated domestic cooking range; and

Fig. 3 is a sectional view of part of a building element, wherein a special heating arrangement is illustrated in relation to adjacent range parts. The building element illustrated in Fig. 1 includes a base unit in the form of a slab 10 consisting of an insulating, ceramic encasement material. The slab 10 is rectangular in shape and the measurements of said slab are adapted to the horizontal cross-section of the cooking range. The slab is suitably made of aluminium oxide. This material is light in weight and somewhat brittle, although the slab 10 will nevertheless be relatively strong mechanically, due to its thickness. The fact that the material is also well-suited to function as a transportation packaging medium, as before mentioned, is to a large part due to the relatively large thickness of the material.

The novel building element shown in Fig. 1 includes four heating units 12, 14, 16, 18 in three different sizes, said units being arranged in corresponding recesses 20, 22, 24, 26 in the ceramic slab 10. The heating units 14, 18 are mutually of the same size. In the illustrated case, each heating unit 12, 14, 16, 18 is comprised of a thin sintered SUPERKANTHAL^® filament, which is relatively brittle when cold. The filament patterns are shown clearly in the Figure. The filaments are very light in weight and have the advantage of retaining their form without weighting down the light encasement material in any way.

Fig. 2 illustrates the novel building element in more detail and shows the element fitted in a domestic cooking range 28 equipped with a ceramic glass hob 30. The Figure shows the upper parts 32, 34 of two mutually opposing sheet-metal side walls of the range 28. As will be seen, the side walls include an upper stiffening frame part 36. The frame part 36 is provided with an inwardly facing flange 38, on which the ceramic glass hob 30 is placed. Extending between the adjacent side edges of the frame part 36 and the hob 30 is a thin silicone layer 40 which functions to seal and affix the hob 30. The novel building element is fitted immediately beneath the hob 30, said building element being pressed in between mutually abutting and inwardly facing side edges 42 of the flange 38. Also shown in Fig. 2 is a metal bracket means 44 which is attached to the flange 40 and abuts with the underside of the building element, so as to press said element lightly against the ceramic glass hob 30.

The building element illustrated in Fig. 2 has two recesses 20, 24 provided in the upwardly facing main side thereof, each of these recesses accommodating a corresponding heating unit 12 and 16 respectively. The measurements of respective recesses 20, 22, 24, 26 are adapted to the measurements of respective corresponding heating units 12, 13, 16, 18, so as to provide a suitable clearance between the inner surface of a recess and the juxtaposed heating element, and between the heating element 12, 14, 16, 18 and the upper side of the building element, i.e. the side that faces towards the hob 30.

The slab 10 consisting of insulating, ceramic encasement material has essentially the same thickness over the major part of its extension. This is made possible by providing the underside of the slab 10 with elevated parts 46, 48 centrally opposite the respective recesses 20 and 24. This arrangement provides a saving in material while enabling the total weight of the slab 10 to be kept down without jeopardizing its mechanical strength.

Each heating unit 12, 14, 16, 18 rests on a plurality of raised parts 50 which constitute part of the material in the ceramic slab 10. The raised parts or projections 50 are conveniently disposed in mutually parallel relationship transversely across the bottom of respective recesses 20, 22, 24, 26. The projections 50 may either be continuous or discontinuous. In this latter case, the projections support- ing a respective heating unit are disposed in mutually spaced relationship along the same line. Each heating unit 12, 13, 16, 18 rests on its projections 50 in respective recesses 20, 22, 24, 26 and is also affixed in relation to said projections. This is achieved with the aid of wire U-shaped fasteners 52 which lock the SUPERKANTHAL^® filaments firmly in relation to the projections 50.

In the case of the illustrated embodiment, two electric wires 54, 56 are drawn from each heating unit 12, 14, 16, 18 for the purpose of enabling said units to be remotely controlled. The two wires 54, 56 extend through a passage which, in the illustrated case, has an upwardly open part 58 which extends in towards the centre of the building element and which then passes transversely through the ceramic slab 10 and opens out at its underside. As will be seen from Fig. 2, the electric wires 54, 56 will pass out into the protected free space 60 between the elevated parts 46, 48 resting on the plate 44. The wires 54, 56 can then be led to a desired place of connection (not shown) without risk of being damaged.

Fig. 3 illustrates a special arrangement of heating units 62, 64 which is advantageous in certain cases. The Figure is a view of part of a novel building element fitted in a partial¬ ly indicated domestic cooking range 66. The range includes a glass hob 68, an insulating plate or slab 70, and a bottom plate 72. The insulating slab 70 includes recesses 74 in which the two separate heating units 62 and 64 are accommo¬ dated. These heating units may be remotely controlled in a conventional manner and may be either series-connected or parallel-connected. As in the case of the Fig. 2 embodiment, the lower heating unit 62 rests on a plurality of upstanding parts or projections 76. The unit is also fixed in relation to said projections with the aid of U-shaped fastener means 78. In the case of this embodiment, an intermediate sheet is placed above the heating unit 62. This intermediate sheet has the form of a grid-like spacer provided with projections 80 which are similar to the projections 76 in all essentials. The projections 76, 80 have the form of longitudinally extending ridges which extend parallel with one another transversely across the recess 74. The heating unit 64 is placed on top of the spacer. The heating unit 64 is fastened to its respective projections 80 in the same way as the heating unit 62, with the aid of U-shaped wire fasteners 82. Naturally, a building element of the kind illustrated in Fig. 3 may be supplemented with additional heating units, which in turn may be placed above the heating unit 64. This provides a building element in which the heating units are located on several levels.

It will be understood that the invention is not restricted to the illustrated and described exemplifying embodiments thereof and that modifications can be made within the scope of the invention. For instance, the ceramic plate may have a planar underside. Furthermore, if desired, the underside of the ceramic plate can be strengthened with a thin metal sheet or with thin metal strips. The elevated parts located in the recesses can be formed in many different ways. It is also feasible to allow an upper heating unit to rest on elevations which extend from the bottom of a recess to a point beyond a lower heating unit. A separate hole may also be provided for each wire connected to a heating unit.

Claims

1. A building unit intended for a domestic cooking range (28; 66) having a ceramic glass hob (30; 68), wherein the building element includes an insulating plate (10; 70) having provided in its upwardly facing main side a measurement- adapted open recess (20, 22, 24, 26; 74) for accommodating a corresponding heating unit (12, 14, 16, 18; 62) forming part of the building element, characterized in that the heating unit (12, 14, 16, 18; 62) comprises a heating filament and rests with a small abutment surface on projec¬ tions (50; 76) upstanding from the bottom of said recess (20, 22, 24, 26; 62), wherein the slab (10; 70) includes at least one passage (58) for accommodating electric wires or the like (54, 56) that are intended for connection to and the remote control of said heating unit, said wires or the like extend¬ ing from the recess (20, 22, 24, 26; 62) to one of the other sides of the slab (10; 70).

2. A building element according to Claim 1, characterized in that each passage (58) opens out on the downwardly facing main side of the slab (10; 70).

3. A building element according to any one of Claims 1 and 2, characterized in that the building element includes at least one further heating unit (64) which is arranged above the first heating unit (62) in the correspondingly measure¬ ment-adapted recess (74) for remote control in essentially the same way as the first heating unit (62) and which rests on a spacer means mounted above the first heating unit (62).

4. A building element according to Claim 3, characterized in that the spacer means has a grid-like configuration.

5. A building element according to any one of Claims 1-4, characterized in that the projections have the form of mutually parallel ridges (50; 76, 80) located adjacent one another in said recess.

6. A building element according to any one of Claims 1 and 2, characterized in that the building element includes at least one further heating unit which is arranged above the first heating unit in the correspondingly measurement-adapted recess for remote control in essentially the same way as the first heating unit and which rests on projections upstanding from the bottom of the recess.

7. A building element according to any one of the preceding Claims, characterized in that the heating unit (12, 14, 16, 18; 62, 64) is fixed relative to the projections (50; 76, 80), the grid and the ridges respectively by means of U- shaped wire fasteners (52; 78, 82).

8. A building element according to any one of the preceding Claims, characterized in that the ceramic slab (10) includes several recesses (20, 22, 24, 26) and corresponding heating units (12, 14, 16, 18) accommodated therein.

9. A building element according to Claim 8, characterized in that the slab (10) has essentially the same thickness over the major part of its extension, and in that the downwardly facing main side of said slab has elevated parts (46, 48) centrally of the recesses (20, 24).

10. A building element according to any one of the preceding Claims, characterized by a bottom plate (44; 72) which functions to support the slab (10; 70) at its downwardly facing main side.

11. A building element according to any one of the preceding Claims, characterized in that the insulating, ceramic encasement material is aluminium oxide; and in that the heating spiral is comprised of a thin sintered SUPERKANTHAL^® filament.