EP0930806B1 - Glas-ceramic plate comprising arelief-patern for tactile locating tactile - Google Patents

Abstract

Tactile controls for hob elements comprise e.g. metal, plastics or, preferably, ceramics inserts (6) with conducting strip bases (14) providing the capacitance required for touch-sensitive circuits, sealed into openings in the hob edge (1), which they completely fill, using adhesive or fusing techniques. Their concave tops rise above the hot surface without ridges or other discontinuities. Adjoining serigraphic symbols (17), themselves, optimally, in slight relief, indicate progressively increasing power levels for the controlled element; optimally, progression is achieved using several sequential inserts. Optimally, the relief surface is fixed directly to the unbroken hob surface, or directly molded within the hob material.

Description

The invention relates to vitroceramic plates for covering heating elements. More specifically, the invention relates to vitroceramic plates used in the constitution of hobs. Such hobs include in particular heating elements such as radiant heaters or halogen fires, and control and regulating means for varying their power.

For such control and regulating means, knobs fixed on axes passing through holes in the glass-ceramic plate are commonly used. This solution is not entirely satisfactory. In the first place, the making of holes in the plate, under conditions preserving sufficient mechanical strength thereof and limiting manufacturing defects and therefore the proportion of products to be discarded, requires the implementation of complex processes. On the other hand, this embodiment of the control means does not allow a perfect cleaning of the plate, because whatever the sealing of the button-plate interface, the peripheral edge of the button necessarily forms a sharp edge or delimits a slot, which do not fail to hang and possibly retain the dust, small crumbs ...

One solution is to replace the conventional control buttons with sensitive keys, according to the teaching of the patent application EP 0 443 924 A1. The control and regulating means for a means of cooking or of keeping in temperature consists especially as described in this document, in a pair of keys, one of which serves to increment the power delivered to the focus associated with each contact of the finger of the user on this key, while the other serves, conversely, to reduce step by step the power of this same focus. According to an alternative, it is possible to provide a multiplicity of keys corresponding to different heating powers. In order to specify the location of the keys and their assignments to the various foci, the document suggests forming, on the upper surface of the glass plate, screen printed or otherwise drawn marks. It is then an essentially visual reference; indeed, although screen-printed patterns are in very slight protrusion (for example of 4 μm at most) with respect to the plane of the plate and constitute a differentiated surface state, they do not allow a purely tactile identification of the control means and how to use them, even by an exercised, blind or other person.

In addition, screen printed markers are undesirable with respect to the cleaning of the plate. They tend to retain the dust and be gradually destroyed by the abrasive action of the cloth or sponge and the chemical attack of the cleaning product.

To remedy this, the patent application EP 0 464 323 A2 proposes, to mark the contours of the heating zones on a glass-ceramic plate, to replace the screen-printed patterns by strips of parallel ridges carved on the surface of the plate. Such a mark has the advantage of being almost indelible and is designed, in particular, not to be affected by the repeated sliding, above it, various utensils (stoves, pans ...). It allows visual identification; a tactile location, for example by a blind user, is of course not described because it does not make sense in the case of too much proximity of the cooking means or temperature maintenance, because of the risk that it comprises.

Other key or marking systems are also described in patent applications FR 2 680 937 A, DE 36 00 109 A and US 3 313 919 A.

The invention therefore aims to provide a glass-ceramic plate whose control zone of the cooking or temperature maintenance means does not require a complex additional step of transformation (making holes, shaping ...), but ensures easy identification, particularly tactile for a blind user, control means.

Accordingly, the subject of the invention is a glass-ceramic plate comprising one or more cooking or temperature-keeping means and one or more associated control means. More specifically, the invention consists in the fact that the glass-ceramic plate has a relief in bosses and / or recesses of dimensions such that it allows a tactile identification of a zone and / or a certain function of the plate, the relief in the form of zones of cooking or temperature maintenance at differentiated heights and / or geometric patterns in close proximity or in coincidence with control means, such as substantially linear continuous or discontinuous, rectilinear or curved, and / or an element connecting at least one of the control means to the cooking means or temperature maintenance associated therewith. A relief according to the invention is feasible without it being necessary to implement a specific additional step in the process of manufacturing the glass-ceramic plate: at most, must we adapt the geometry of the support or molding surfaces or pressing to which the plate must conform and which, ordinarily, were flat. On the other hand, the ease of a tactile location is easily obtained by a judicious choice of the geometry of the relief. Another advantage, obtained in addition thanks to the invention, is the almost indestructible and indelible character of the relief, despite the multiple mechanical and chemical aggression to which it can be subjected.

In order to guarantee a tactile location under the best conditions, the height of the relief is at least 15 μm and preferably 0.2 mm, the latter value being easily reproducibly attained by conventional molding methods. "Height" of the relief in the sense of this embodiment means its dimension in the direction perpendicular to the plane of the plate, that is to say so the difference in level between its highest point and its lowest point. This height advantageously does not exceed 50 mm; a higher height would indeed be useless, even embarrassing, for reasons of ergonomics, congestion and difficulty of the training process.

According to a particularly advantageous embodiment of the invention, the environment of the registration relief on the plate has a substantially smooth surface state, said relief constituting a continuous variation. The control zone is then free of streaks, enamelled lines (screen-printed, etc.) and any sharp edge in outgrowth or hollow, likely to be hung up and possibly chipped or otherwise affected, in particular by a kitchen utensil, or retain the dust so that it can be removed only with difficulty by cleaning.

On the contrary, the substantially smooth surface finish eliminates the problem of progressive abrasion of the screen printed patterns, minimizes the risk of chipping due to mechanical shock and allows perfect cleaning of the control area.

Another object of the invention consists of a cooking appliance comprising a glass-ceramic plate as described above.

On the other hand, the subject of the invention is also a method of manufacturing this vitroceramic plate. This method comprises precisely a formatting of the plate consisting of a collapse, molding or pressing operation, using a support or molding or pressing surfaces having the desired geometry, in particular in their part corresponding to the zone of control of the plate.

The collapse, molding or pressing can be carried out at any time by a conventional method of manufacturing a glass-ceramic plate, provided that the material constituting it is at a sufficiently high temperature to prevent plastic deformation. Such a conventional process is described in patent FR 2,657,079.

• la figure 1a est une vue de dessus d'une plaque vitrocéramique selon l'invention,
• la figure 1b est une vue en coupe selon l'axe A-A de cette plaque,
• la figure 1c est une vue en coupe selon l'axe B-B de cette plaque,
• les figures 2, 3 et 4 sont des représentations schématiques partielles en perspective d'exemples de réalisation distincts d'un relief selon l'invention.

Other features and advantages of the invention will become apparent from the following description of an exemplary embodiment, based on the appended drawings, in which:

• FIG. 1a is a view from above of a glass-ceramic plate according to the invention,
• FIG. 1b is a sectional view along the axis AA of this plate,
• FIG. 1c is a sectional view along the axis BB of this plate,
• Figures 2, 3 and 4 are partial schematic representations in perspective of different embodiments of a relief according to the invention.

With reference to FIGS. 1a, 1b and 1c, the vitroceramic plate 1, of conventional thickness and constituent material and known in the prior art, comprises four foci 2, 3, 4 and 5. These foci are indifferently radiant, halogen or induction. However, there is no reason why, contrary to what is shown, one of the cooking hobs should consist of a gas burner installed in an opening in the plate, as described, for example, in the patent application. EP 0 715 125 A1.

The plate 1 is provided at the anterior portion of its upper surface with a protruding relief 6 having the shape of a transverse segment. This segment marries, for aesthetic purposes but also for the sake of rational use of the surface of the plate, the slight curvature of the front edge of the latter. It appears in Figure 1c that the relief 6 is devoid of sharp edge. The relief 6 allows sensory identification of the control zone of the foci 2, 3, 4 and 5. Sensory keys 7, 8, 9 and 10 for controlling and regulating the foci 2, respectively 3, 4 and 5 are arranged immediately. front and along the relief 6, from left to right in Figure 1a, that is to say, in accordance with the provision of households to which they are assigned. The substantially linear shape of the keys 7, 8, 9, 10 and the relief 6 is particularly suitable for selecting a heating power, determined according to the position of the finger on the key or the distance traveled. by the finger on the key.

The relief is here positioned near the control means 7, 8, 9 and 10 which are further delimited by a marking screen printed on the plate.

According to a preferred variant of the invention, it would also be possible to eliminate this screen-printed marking in order to give the control zone a substantially smooth surface state in the sense indicated above. One way to overcome the screen printing marking is for example to conform the relief 6 in individualizable elements each associated with a control means at most, including clearly identifiable elements assigned to each of the cooking stoves to ensure the control and the regulation.

It is for example conceivable to create discontinuities in the relief 6 as drawn in the appendix, in front of the interstices separating the sensitive keys 7 and 8, 8 and 9, 9 and 10. The control of a home is done at the location of the appropriate touch pad, lacking its identification in enamelled lines, more precisely in front of and in the immediate vicinity of the appropriate element of the relief 6.

According to another embodiment, the relief 6 coincides with one or more control means. It can be formed here again into individualizable elements, coinciding, for example, simply with the sensitive keys 7, 8, 9 and 10 of FIG. 1a, in which case the screen-printed marking becomes superfluous.

All other practical forms of relief 6 for the control means are conceivable. Conveniently, relief elements positioned relative to one another are provided in the same manner as the various cooking stoves; these relief elements are used to designate the controlled cooking zone. To select the heating power, a conventional circular arrangement of clockwise increasing powers may be convenient. Each power level can be identified by a raised figure or a geometric pattern of correspondingly increasing size. Moreover, all other geometric shapes such as square, rectangular, triangular, circular, oval, polygonal concave or convex, regular or not, in a rounded, quasi-linear or point-like slope can be used in the constitution of the locating relief.

At the time of forming the relief 6, an elevation 11, including the hobs 3 and 4, was created in the same way. The elevation 11 has no sharp edge, and therefore allows easy cleaning and perfect.

The creation of elevation meets aesthetic concerns, but also practical. Thus, according to one variant, a particular elevation of the plate corresponds to each of the cooking hobs, all these elevations being separated from each other by a part of the upper surface of the plate of lower height. In case of leakage of liquid from the cooking vessel, this liquid flows on this portion of lower height, thus avoiding the plate area corresponding to the cooking hobs themselves, likely to reach the maximum temperatures. This prevents the escaped liquid from being heated to a solid and adherent deposit; the cleaning of the plate is facilitated. On the other hand, the elevation of the zone 11 of the rear cooking stoves 3 and 4 minimizes the effort required to deposit cooking containers on these homes or, on the contrary to remove them, while passing them over possible other containers placed on one of the front foci 2 and 5.

Furthermore, at least part of the relief 6 may consist of an element, not shown, connecting at least one of the control means 7, 8, 9, 10 to the cooking or temperature keeping means 2, 3, 4 , 5 which is associated with it. It may be a hollow channel in the plate or a protrusion of equivalent shape. An element of identical shape to that just described may itself be a touch-sensitive control means, the heating power selected being then advantageously proportional to the channel length or equivalent shape of protuberance described by touch of a finger.

Another variant concerns the case of a modular glass-ceramic plate, that is to say consisting of an assembly of elementary parts of any shape identical or different (triangular, rectangular, square, in arcs of circles ...). According to this variant of a particularly easy embodiment, a portion of the relief 6 is disposed between the edges of neighboring elementary parts of the plate; this part of the relief 6 constitutes or comprises, if necessary, sensory control keys of the cooking hobs.

The plate 1 is embedded in a known manner in a work plane, which appear the front edges 12 and posterior 13.

In each of FIGS. 2, 3 and 4 there is shown a glass-ceramic plate 1, a control touch pad of one or more cooking or temperature-keeping means which comprises a raised control surface 6 and a capacitive element 14.

As represented in FIG. 2, the relief 6 is formed by the emergent part of an insert housed in a recess passing right through a peripheral zone of the plate 1. According to another embodiment, the insert could be positioned between the adjacent edges of two elementary modules constituting the plate. The insert is metallic, made of plastic or, preferably, a glass material such as glass-ceramic. It is optionally secured to the plate 1, depending on the material that constitutes it, by gluing, welding of glass material, etc.

Screen printed patterns 17 are markers of selected power levels.

According to the variant of Figure 3, the relief 6 consists of an element simply attached to the plate 1. This element is made in the same group of materials as those of the aforementioned insert; it is secured to the plate 1.

According to another embodiment shown in Figure 4, the relief 6 is formed in the material constituting the glass-ceramic plate 1 itself, in particular by collapse, molding or pressing as mentioned above.

Therefore, the glass-ceramic plate of the invention facilitates the maintenance of perfect cleanliness; the means of locating the means of control, consisting of a relief in the material of the plate or in another material, offers an optimal resistance to mechanical and chemical aggression. Its formation presents no difficulty, but integrates into the conventional process of manufacturing glass-ceramic plates, without causing additional investments. All control operations and manipulations relating to this plate are made possible in the absence of any visual approach, thanks to the concept of integral tactile tracking implemented.

Claims (10)

1. Glass-ceramic plate (1) comprising one or more means of cooking or of keeping at temperature (2, 3, 4, 5) associated with one or more control means (7, 8, 9, 10), the said plate having a relief (6) with bosses and/or with recesses of dimensions such that it allows a tactile identification of a determined zone and/or of a determined function of the plate (1), characterized in that the relief (6) is presented in the form of zones (11) of cooking or of keeping at temperature with differentiated heights and/or of geometric patterns immediately adjacent to or coinciding with control means (7, 8, 9, 10), such as substantially continuous or discontinuous linear, rectilinear or curved patterns, and/or of an element connecting at least one of the control means (7, 8, 9, 10) to the means of cooking or of keeping at temperature (2, 3, 4, 5) that is associated therewith.
2. Glass-ceramic plate (1) according to Claim 1, characterized in that the height of the relief (6) is at least equal to 15 µm.
3. Glass-ceramic plate (1) according to Claim 2, characterized in that the height of the relief (6) is at least equal to 0.2 mm.
4. Glass-ceramic plate (1) according to one of Claims 1 to 3, characterized in that the height of the relief (6) is less than 50 mm.
5. Glass-ceramic plate (1) according to one of Claims 1 to 4, characterized in that the environment of the relief (6) on the plate (1) has an essentially smooth surface state, whose relief (6) constitutes a continuous variation.
6. Glass-ceramic plate (1) according to one of Claims 1 to 5, characterized in that the relief (6) is formed in the material constituting the glass-ceramic plate (1) itself.
7. Glass-ceramic plate (1) according to one of Claims 1 to 5, characterized in that the relief (6) is formed by the addition of an appropriate element on the plate (1).
8. Glass-ceramic plate (1) according to one of Claims 1 to 7, characterized in that at least one control means (7, 8, 9, 10) consists in a sensor pad.
9. Cooking device comprising a glass-ceramic plate (1) according to one of Claims 1 to 8.
10. Method of producing a glass-ceramic plate (1) according to one of Claims 1 to 8, characterized in that it comprises a forming which consists in an operation of settling, moulding or pressing the material constituting the plate (1), with the aid of a moulding or pressing medium or surfaces having the desired geometry.

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