Apparatus for cooking food products in a quick manner on both sides thereof

Abstract

Apparatus for cooking food products on both sides thereof, comprising a base member associated to a bottom heating surface, a first electric heating element located between the base member and the bottom heating surface, an upper movable member associated to a top heating surface, a second electric heating element located between said upper member and said top heating surface, and one or more microwave generators housed in the base member; when said upper member is lowered, the top heating surface comes to lie opposite to the bottom heating surface so as to form a cooking cavity therebetween. Said first electric heating element is separated from the bottom heating surface by a hollow space and the microwave generator is placed in such position, with the use of appropriate wave-guide means, as to allow the microwaves issuing therefrom to propagate towards said hollow space and, eventually, towards the bottom surface of said bottom heating surface.

Description

The present invention refers to an improved kind of griddle or plate for cooking food products in a quick manner on both sides thereof.

Widely known in the art are currently broilers, or griddles, that are used to cook food products of the most varied kind, such as hamburgers, toasted rolls, meat in general, and the like.

The features and peculiarities of such griddles are extensively described in the European patent application EP 06 111 596.0 filed by this same Applicant, which reference should therefore be made to for reasons of brevity and greater illustrative simplicity.

Griddles of the kind described in the above-cited document have proven to be simple to manufacture and easy to operate; however, in practical use they have been found to be connected with a particular drawback tending to affect their capability of being used in a satisfactory manner and, as a result, their actual acceptance by the users, such drawback lying practically in the fact that the heating elements (27) are placed and arranged in close proximity of the bottom heating surface (3) and the microwave generator is in turn provided under said heating surface and, as a result, also under said heating elements, and is of course oriented upwards. It therefore ensues that the microwaves have necessarily to pass through said heating elements, which turn in this way out as undesirably forming an ample shield opposing the propagation thereof and preventing in a clearly appreciable manner the same microwaves from being able to fully efficiently and effectively reach the food product placed upon said bottom heating surface.

Needless to say that such main problem is further aggravated by the drawbacks deriving from electromagnetic coupling problems brought about by such unacceptable shielding effect created by the heating elements.

Known from the disclosure in WO 03/098972 (O ZON INC.) is an apparatus for processing small food portions, such as toasted and filled rolls, small pizzas and the like, with the aid of microwaves. This apparatus is made so as to feature small cavities or chambers having a flat bottom and raised peripheral edges, and such chambers are capable of being closed from above by means of a kind of microwave-tight cover; in addition, such chambers can be heated with the use of heating means of any traditional kind as largely known as such in the art, so that the food product being placed inside these cooking chambers for processing, is exposed to both a conventional heating treatment and a microwave heating treatment at the same time when the related chamber is closed.

No indication is however given however in the above-cited document as to how the traditional, or thermal, heating means can be prevented from at the same time acting as a shield opposing microwave propagation, nor any teaching is given there, either, as to the construction measures that can be taken in view of avoiding such undesirable effect.

Known from the disclosure in WO 99/44394 is an apparatus from cooking foods by both traditional electric heating and microwave heating; however, the food products being cooked—although fully capable of being baked, i.e. grilled in a traditional manner, owing to the two mutually opposing grilling/heating surfaces (2′) being able to be displaced into contacting the food to be cooked (4)—cannot practically being treated with the emission of microwaves in any satisfactorily even manner, since such microwave emission takes place in a direction that is parallel to said grilling/heating surfaces themselves. Moreover, the cavity or chamber, in which the food to be processed is contained and retained can be closed through a double handling calling for the bottom grilling/heating surface to be displaced, i.e. moved horizontally and the top grilling/heating surface to be lowered, thereby adding inconvenience in the use of the apparatus and lengthening the time usually needed to operate it, further to introducing complications in the construction of the same.

It would therefore be desirable, and it is a main object of the present invention, actually, to provide an apparatus for grilling and, at the same time, treating food products by means of microwaves, which can be easily and conveniently opened with a simple handling, such as a simple griddle or similar appliance that can be opened from above, i.e. of the top opening kind, and is capable of grilling food products on both sides thereof at the same time.

According to the present invention, this aim is reached a kind of apparatus, in particular of the type intended for use in commercial foodservice and mass-catering applications, incorporating the features as defined and recited in the appended claims.

Features and advantages of the present invention will anyway be more readily understood from the description that is given below by way of non-limiting example with reference to the accompanying drawings, in which:

FIG. 1 is a front and cross-sectional elevational view of a food cooking apparatus according to the present invention, as represented in a symbolical, simplified manner with its upper plate raised in the resting, i.e. inoperative position thereof;

FIG. 2 is a similar view of the food cooking apparatus shown in FIG. 1, however represented in the state in which its upper plate is lowered into the cooking position thereof;

FIGS. 3 and 4 are corresponding views of a simplified embodiment of the apparatus shown in the preceding Figures, as viewed with its upper plate raised in the inoperative position thereof and lowered in the cooking position thereof, respectively;

FIGS. 5 and 6 are views of a different embodiment of the apparatus shown in the preceding Figures, as viewed with its upper plate raised in the inoperative position thereof and lowered in the cooking position thereof, respectively;

FIG. 7 is a see-through top view of the upper plate shown in FIGS. 5 and 6;

FIGS. 8 and 9 are views of a further different embodiment of the apparatus shown in the preceding Figures, as viewed with its upper plate raised in the inoperative position thereof and lowered in the cooking position thereof, respectively;

FIGS. 10 and 11 are views of a variation introduced in the embodiment of the apparatus shown in FIGS. 8 and 9, as viewed again with its upper plate raised in the inoperative position thereof and lowered in the cooking position thereof, respectively;

FIG. 12 is a simplified, outer perspective view of the cooking apparatus according to the present invention.

An apparatus for cooking a food product 1 as it is generally known from the prior art comprises:

• • a base member 2 associated to a lower or bottom heating surface 3 adapted to support food products to be cooked,
  • an upper member 4 associated to an upper or top heating surface 5 and pivotally joined to the base member 2 so that, when the upper member 4 is lowered or swung towards the base member 2, the top heating surface 5 moves close to the bottom heating surface 3 supporting the food to be cooked, so as to enclose the latter therebetween.

Said bottom heating surface 3 supporting the food to be cooked and said top heating surface 5 are made of a rigid material that is transparent to both microwaves and radiated heat without being damaged by them, either, as typically constituted by glass-ceramic plates as generally known as such in the art.

The kind of movement needed to lower the upper member 4, i.e. the top heating surface 5 onto the bottom heating surface 3 lying therebelow can for instance be a rotary one about a hinging pin provided on the base member 2 or a simple translational one, or a combination of both. Anyway, these details shall not be explained any further, owing to them being generally and widely known to all those skilled in the art.

Said base member 2 and said upper member 4, when closed in against each other, are adapted to define—in the volume comprised therebetween—a gap in which there are placed the food products to be cooked, and in which there are of course provided also said heating surfaces 3 and 5.

The afore-cited microwave generators may consist of either a single generator or a plurality of generators; accordingly, even the internal configuration of said base member may vary. Such circumstance shall however be explained and illustrated in greater detail further on.

The bottom heating surface 3 covers and substantially closes the area on top of the base member 2 and, similarly, the top heating surface 5 covers and substantially closes the area at the bottom of the upper member 4.

According to the present invention, and with reference to the illustrations in FIGS. 1 and 2, under said bottom heating surface 3 there is arranged a first electric heating element 14, which is anyway housed within said base member 2, and, in a fully similar manner, above said top heating surface 5 there is arranged a second electric heating element 15, which is anyway housed within said upper member 4.

Both said heating surfaces 3 and 5 are made of a material that is resistant to high temperatures and substantially transparent to both microwave and infrared radiation, so that heat produced by said electric heating elements 14 and 15 passes directly on to the food 1 being cooked.

In addition, inside said base member 2 there are housed one or more microwave generators 7A, 7B for them to be able to irradiate the food products enclosed within said heating surfaces 3 and 5; the same cooking cavity formed by said base and upper members when closed against each other defines and forms a microwave screen adapted to retain the same microwaves therewithin, i.e. prevent them from leaking outside.

In the case illustrated in FIG. 2, within said base member 2 there are provided two distinct microwave generators 7A and 7B, which are positioned as described below, i.e.:

• • they are located at the sides of said first electric heating element 14, and
  • they are arranged so that the respective microwaves propagating therefrom can—following an inclined path and without passing through said first electric heating element 14—reach and hit the bottom or lower face 17 of said bottom heating surface 3; in the case that said microwave generators 7A and 7B are placed quite at the side of, i.e. in a markedly lateral position relative to said first electric heating element 14, or in a position quite down below said first electric heating element 14, the above-cited condition can be alternatively complied with by also providing suitable waveguide channels 16, 18, as generally known and such in the art and preferably provided in the same base member as shown in the Figures, which will then appropriately convey said microwave propagations towards said bottom face 17.

In view of ensuring the occurrence of the above-cited conditions, said first electric heating element 14 must of course be adequately and appropriately spaced from said bottom heating surface 3; as a result, a hollow space 19 is created between said bodies 3 and 14.

In order to support said first electric heating element 14, and also in view of preventing it from being able to be reached by the microwaves issued by and propagating from the generator 7A, i.e. an occurrence that would give rise to easily and clearly imaginable electromagnetic coupling and interference problems, underneath said same first electric heating element 14 there is placed a first shielding means 20, which is typically configured in the form of a planar sheet-metal plate so arranged as to extend under said first electric heating element 14; preferably, however, said first shielding means is provided with one or more upward-oriented side walls 21 joining to a perforated metal member 21A, which is arranged so as to extend between the electric heating element 14 and the bottom heating surface 3, and which is typically provided in the form of a grid or meshwork of metal wires (transparent to infrared radiation, but not to microwaves), so as to form a box-shaped member that is effective in ensuring that the first electric heating element 14 contained therewithin is fully shielded from and unaffected by the microwaves being emitted.

For it to be able to ensure a thermal protection of the other members and parts of the apparatus mounted therearound against the heat generated by the heating element, while at the same time allowing microwaves to pass therethrough without any attenuating effect whatsoever, in an advantageous manner said upright metal shielding provision 21 is coupled internally to two walls 22, which are also extending vertically in a position opposing said first electric heating element 14 at both sides thereof, and which are made of a heat-insulating, microwave-permeable material, such as a ceramic-fibre material as it is largely known as such in the art.

In an advantageous manner, these walls 22 may be provided so as to continue to eventually join into a semi-peripheral member 22A extending below the respective first electric heating element 14 and—of course—also above said shielding means 20, so as to reduce heat losses downwards from the radiation area of the heating element 14.

Moreover, these walls 22 delimit—in correspondence to the food support area of the heating surface 3—the cooking zone C for both the heat radiated by the heating element 14 and the microwave energy to be able to safely propagate therewithin. Conversely, in the cooking zone D extending annularly around said cooking zone C externally thereto, only microwaves are allowed to flow and propagate so as to hit the food—placed upon the heating surface and extending also outside the cooking zone C as defined above—from both the sides and above (FIG. 3).

Referring again to FIGS. 1 and 2, the second electric heating element 15 is in turn surrounded—above and at the sides thereof—by a second heat shielding means 25, whose lower edges 23 are firmly and solidly connected to the upper face 24 of the top heating surface 5; in addition, even this second or upper electric heating element 15 is surrounded by a metal shielding protection casing 26, 27 that extends further under said heating element 15 into a perforated sheet-metal plate 27A, or the like, in a manner that is fully similar to how the afore-cited parts 20, 21 and 21A are used to surround said first or lower electric heating element 14, albeit in a roughly mirror-image arrangement relative thereto.

Advantageously, even said second heat shielding means 25 is made using a material that has the same properties as the material used for the afore-cited first shielding means 22 and 22A.

While the bottom heating surface 3 is supported upon said base member 2 by means that are generally known as such in the art, such as by appropriately providing said base member with a bracket-like contour 28 (FIG. 3) acting as a support for such heating surface, the top heating surface 5 may on the contrary be associated to the respective heating element through a connection and support framework or casing 29 that is shaped as illustrated in FIGS. 3 and 4, i.e. internally hollow so as to form a downward-oriented cavity adapted to contain:

• • said shielding casing 26, 27,
  • said perforated plate 27A,
  • along with the various devices and parts associated thereto, i.e. the heat shielding
  • means 25 and the second electric heating element 15, therewithin, while being joined to the edges 29A of said top heating surface 5, so as to form a rigid and solidly built assembly on the whole.

A cooking apparatus is in this way provided, which is adapted to process any food product 1 that is placed upon said bottom support and heating surface 3 by both thermal effect, i.e. by grilling it under radiated heat, and microwave heating effect.

In fact, upon placing said food product 1 thereupon, all it takes is lowering said upper movable member 4 so as to close it in on said base member 2 and ensure that the thereby automatically formed cooking cavity or chamber 6 features a tightly sealed construction and can in addition be both irradiated, i.e. hit by the infrared radiation emitted by the two electric heating elements 14 and 15 from both opposite sides of the food product being exposed, and reached by the propagating microwaves that pass through both said insulating walls 22 and the bottom support and heating surface 3 in an ascending flow pattern.

The microwave propagation reaches in fact the lower or bottom side of said support surface 3 through the passage provided between said surface and the perforated surface of said metal shielding means 27 to eventually pass through the same surface 3 and hit the food product placed thereupon; furthermore, the microwave propagation is positively prevented from being able to reach the lower electric heating element 14 owing to its being guarded off by the same metal shielding means 27, whose perforations are on the other hand such as to allow the respective infrared radiation to pass therethrough and reach the bottom face of the food support surface 3.

A fully similar process takes place within the upper movable member 4 in connection with the second electric heating element 15 provided thereinside, so that it shall not be described again for reasons of greater simplicity.

As far as the operation of the above-described cooking apparatus according to the present invention, it will be capable of being operated in the microwave-only mode, in the infrared heat-only mode, as well as in the combined mode using both microwaves and infrared heat.

Further and more sophisticated operating modes can in addition be provided, in which the power levels being generated and output can for instance be modulated and regulated in a useful manner. Such operating modes, however, are fully similar to those generally available in combination ovens using microwaves and traditional heat as currently available on the market, so that—owing to them being largely known to and within the abilities of all those skilled in the art—they shall not be explained any further.

Although only two microwave generators are represented in the afore-cited Figures as generally indicated at 7A and 7B, it shall be appreciated that even more than two microwave generators may be provided and used in the inventive apparatus, as well.

With reference to FIGS. 3 and 4, an alternative configuration to the use of two distinct microwave generators calls for the use of a single microwave generator 8, which is placed immediately under said first shielding means 20, wherein the surrounding volumes and parts will of course be so sized as to allow for such situation and arrangement.

Advantageously, said single microwave generator 8 is placed in a central position relative to the bottom heating and food support surface 3 lying thereabove, so as to enable the food to be treated in a more even and homogeneous manner by the microwaves issuing therefrom. Furthermore, appropriate waveguides 9 need to be provided in this particular case, wherein such waveguides have to be designed and arranged so as to ensure that the microwave propagation from said microwave generator 8 is effectively able to reach said bottom heating and food support surface 3 under just a minimum of losses.

As already stated above, when the upper movable member 4 of the apparatus is lowered to close in on the base member 2, the lower edges 41 of said upper movable member 4 close against the corresponding upper edges 42 of the base member 2, thereby providing the cooking cavity or chamber 6 adapted to confine the microwaves therewithin.

In order to ensure that said top heating surface 5 will effectively move into and take the right position relative to the food to be cooked after said upper movable member 4 has been lowered, and taking into due consideration also the fact that such right position may also correspond to a height of said member, at which said top heating surface 5 is not in contact with the food product to be treated, such as in the case of small pizzas and similar food items, following improvements are proposed.

With reference to FIGS. 5 and 6, the afore-mentioned framework or casing 29, along with the various parts and devices as described afore, is connected to said upper movable member 4 by means of two guide grooves 31, 32 provided integrally with or, anyway, firmly joined to said upper movable member 4 inside the latter and oriented downwards, in the shape of a U with the open side facing inwards, and two respective sliding arms 33 and 34 provided integrally with or, anyway, firmly joined to said framework or casing 29 so as to extend horizontally therefrom, and adapted to slidably fit into the respective ones of said open sides of said U-shaped grooves.

Conclusively, the above-noted parts and members are so sized and positioned relative to each other as to ensure that said framework or casing 29, along with all devices associated thereto, i.e. basically the shielding casing 26, 27, 27A and the second electric heating element 15 that form a rigid and firmly joined assembly on the whole, is able to rise and sink, i.e. move up and down relative to said upper movable member 4, while being guided in these displacements thereof by said sliding arms 33 and 34 slidably engaging the respective grooves 31, 32.

As a result, when the upper movable member 4 is lowered, said top heating surface 5 is moved into contact with the corresponding portion of the food product to be cooked, thereby pressing it slightly due to the weight of the various devices and parts associated and joined thereto as described above, i.e. the framework 29, the shielding casing 26, 27, 27A and the second electric heating element 15.

With reference again to FIGS. 5 and 6, in the case that the so obtained pressing effect upon the food product proves to be too limited, i.e. inadequate, for said top heating surface 5, in the case that the so obtained pressing effect upon the food product proves to be too limited, i.e. inadequate, in order to ensure that said top heating surface 5 is able to automatically be brought or caused to adequately press against and firmly stabilize upon the upper portion of the food product, it is possible for such pressure to be increased through the application—between the inner surface of the upper movable member 4 and the outer or upper surface of the metal shielding member 26, 27—of two elastic elements 35, 36, preferably spiral or coil springs suitably anchored at the respective end portions thereof, such as to enable the total force that can be exerted—when lowered into the closed position thereof—by said upper movable member 4 (and the related top heating surface 5) upon the food product lying therebelow to be increased in a fully controllable manner.

When handling particular kinds of food products, such as small pizzas, canapés, and the like, the need may also arise for the food product to be heated from both the bottom and above, while however avoiding any contact of the heating surface with the upper portion of the same food product, the basic requirement calling for the whole food product to be irradiated by the microwaves remaining on the other hand fully unvaried. In this case, with reference to FIGS. 8 and 9, on the upper surface of the metal shielding member 26, 27, or the framework 29, there is advantageously applied, in a firmly joined manner, a threaded rod 40 that extends upwards and passes through the upper wall of said upper movable concave member 4, said wall being provided with an appropriate through-bore 41 to such purpose. Onto the portion of said rod 40 that extends above said upper movable member 4 there is screwed a kind of handwheel 42 that engages the threading on said rod.

Comparing now the illustrations in FIGS. 8 and 9 with each other, it can be readily appreciated how the above-described contrivance operates, actually. In fact, all it takes is rotating said handwheel 42 in the appropriate direction to cause it to slide, i.e. displace downwards along said rod 40, until it eventually comes into contact with the upper surface 43 of said upper movable member 4.

If the handwheel 42 keeps at this point being screwed on, the same handwheel—owing to its being clearly unable to move downwards any further due to the resistance opposed by said upper movable member 4—will start by reaction attracting upwards (corkscrew effect) the threaded rod along with the whole framework 29 and—jointly therewith—the assembly comprised of the shielding casing 26, 27, 27A and the devices and parts associated thereto, i.e. the upper electric heating element 15, the top heating surface 5 and the second thermally insulating protection means 25.

Accordingly, the whole assembly as defined above can be raised up to a predetermined height so that the top heating surface 5 is positioned at the desired distance above the food product to be treated.

The above-described solution may of course be also embodied in other different forms and manners; so, for instance, and with reference to FIGS. 10 and 11, a particularly simple embodiment thereof may consist in providing the upper movable member 4 with a first-class lever 50, 51 pivoted about a fulcrum located on a pin 52 applied on a vertical side wall 53 of said upper movable member 4. The resistance arm 50 of said lever 50, 51 penetrates into the cavity of said upper movable member 4 to get engaged against the afore-noted sliding arms 33 and 34. The effort arm 51 of said lever is on the contrary located—with at least a portion thereof—on the outside of said upper movable member 4 and, as a result, is conveniently accessible to the user/operator. Therefore, when said effort arm 51 is pushed downwards, the resistance arm 50 inside the cavity of the upper movable member 4 is caused to rise, thereby lifting also the framework 29 jointly with the whole assembly comprised of the casing 26, 27, 27A and the devices and parts associated thereto, i.e. the upper electric heating element 15, the top heating surface 5 and the second thermally insulating protection means 25. This enables the desired effect to be obtained of raising the top heating surface 5 up to a pre-determined height, so as to position it above the food product to be treated at a desired distance therefrom.

A cooking apparatus is in this way provided, which—as this has been experimentally found and proven in a quite extensive and exhaustive manner—enables food products to be instantaneously cooked on both sides thereof by exposing them to both traditional heat and microwaves. In addition, this apparatus enables cooking times to be reduced to a quite significant extent, which certainly is a much sought-after feature in commercial and mass-catering foodservice applications, without burning the food products themselves.

A further advantage of inventive apparatus lies in the fact that it allows food products to be handled, i.e. cooked, which may vary to also a considerable extent in size, i.e. may have widely differing heights and extensions, thanks to the top heating surface that can be easily adjusted.

Claims

1. Apparatus for instant-cooking food products (1) on both sides thereof, preferably of the type intended for use in commercial and mass-catering foodservice operations, comprising: a base member (2), on which there is placed a bottom heating surface (3) acting also as a food support surface, a first electric heating element (14) located between said base member and said bottom heating surface, an upper movable concave member (4) pivotally linked with said base member, so as to be able to be lowered towards and close in on the latter so that, when said upper movable member (4) closes in with the lower edges (41) thereof against the upper edges (42) of said base member (2), a cooking cavity or chamber (6) is created therewithin as delimited downwards by said bottom heating and food-support surface (3), at least a microwave generator (7A, 7B) contained in said base member (2) ad 25 adapted to irradiate the food products contained in said cooking cavity, characterized in that a top heating surface (5) is provided in said cooking cavity (6) to lie above said bottom heating and food-support surface (3), is associated in a firmly joined manner to said upper movable member (4), is adapted to be heated by a second electric heating element (15), and is adapted to engage and retain—between it and the bottom heating and food-support surface (3) lying opposite thereto—the food product being cooked, said first electric heating element (14) is separated from said bottom heating and food-support surface (3) so that a hollow space (19) is formed therebetween, said at least one microwave generator (7A, 7B) is placed in such position, and is provided with such appropriate waveguide means (16, 18), as to allow the microwaves issuing therefrom to propagate towards and into said hollow space and, eventually, towards the bottom face of said bottom heating and food-support surface (3).

2. Instant-cooking apparatus according to claim 1, characterized in that there are provided heat-insulating walls (22, 22A) formed so as to enclose said first electric heating element (14) at the sides and the bottom thereof, and adapted to thermally insulate said first electric heating element (14) so that the heat emitted by the latter is confined by said walls and directed to reach said bottom heating and food-support surface (3) at a pre-defined central zone (C) thereof.

3. Instant-cooking apparatus according to claim 1, characterized in that there is provided a metal shielding means (20, 21) enclosing said first electric heating element (14) at the sides and the bottom thereof, wherein an extension (21A) thereof, which is so perforated or interwoven as to feature perforations or meshes that are effective in warding off microwaves, is interposed between said bottom heating and food-support surface (3) and said first electric heating element (14) lying therebelow.

4. Instant-cooking apparatus according to claim 2, characterized in that said at least one microwave generator (7A, 7B) is placed laterally relative to said first electric heating element (14) in a position outside said first metal shielding means (20, 21, 21A).

5. Instant-cooking apparatus according to claim 2, characterized in that said microwave generator is a single microwave generator (8) and is placed in a position below said first metal shielding means (20).

6. Instant-cooking apparatus according to claim 1, characterized in that there is provided a second metal shielding means (27A) provided with a plurality of perforations or apertures, wherein said second shielding means is interposed between said second electric heating element (15) and said top heating surface (5).

7. Instant-cooking apparatus according to claim 6, characterized in that said second metal shielding means extends at the sides of and above (26, 27) said second electric heating element (15).

8. Instant-cooking apparatus according to claim 6, characterized in that there is provided a heat insulating means (25) enclosing said second electric heating element (15) both along its sides and thereabove, wherein the lower edges (23) of said means are joined to the upper face (24) of said top heating surface (5).

9. Instant-cooking apparatus according to claim 6, characterized in that there is provided a framework (29) having a substantially concave configuration, which encloses the assembly comprised of said second electric heating element (15), the related heat-insulating means (25) and the metal shielding means (27, 27) both along its sides and thereabove, and which joins with its lower extremities to the edges (29A) of said top heating surface (5).

10. Instant-cooking apparatus according to claim 6, characterized in that between said framework (29) and said upper movable member (4) there are provided guide means (31, 32) extending vertically and firmly joined to said upper movable member (4), and in that said framework (29) is provided with sliding means (33, 34) adapted to slidably engage respective ones of said guide means (31, 32).

11. Instant-cooking apparatus according to claim 10, characterized in that there are provided elastic means (35, 36), preferably in the form of spiral or coil springs, between the inner surface of said upper movable member (4) and the upper surface of said framework (29).

12. Instant-cooking apparatus according to claim 1, characterized in that there are provided adjustment means adapted to enable said framework (29), or the upper side (26) of said metal shielding means (26, 27), to be positioned at pre-definable distances relative to the upper surface (43) of said upper movable member (4).

13. Instant-cooking apparatus according to claim 12, characterized in that said adjustment means comprise a threaded rod (40) that is firmly joined, at a lower extremity thereof, to the upper surface of said framework (29) and passes with the central portion of its body through the upper wall of said upper movable member (4) via a through-bore (41) provided therein, and in that a handwheel (42) is adapted to externally engage the threading on said threaded rod (40) and is further adapted to rotate relative thereto so as to be able to be positioned at pre-definable heights.

14. Instant-cooking apparatus according to claim 12, characterized in that said adjustment means comprise a first class lever (50, 51) featuring a fulcrum (52) at the centre thereof, said fulcrum being located on a side wall (53) of said upper movable member (4), wherein the resistance arm (50) of said lever penetrates into said upper movable member (4) and is adapted to engage appropriate portions (33, 34) of said framework (29), and wherein the effort arm (51) of said lever is at least partially extending outside said side wall (53).

15. Instant-cooking apparatus according to claim 2, characterized in that there is provided a metal shielding means (20, 21) enclosing said first electric heating element (14) at the sides and the bottom thereof, wherein an extension (21A) thereof, which is so perforated or interwoven as to feature perforations or meshes that are effective in warding off microwaves, is interposed between said bottom heating and food-support surface (3) and said first electric heating element (14) lying therebelow.

16. Instant-cooking apparatus according to claim 3, characterized in that said at least one microwave generator (7A, 7B) is placed laterally relative to said first electric heating element (14) in a position outside said first metal shielding means (20, 21, 21A).

17. Instant-cooking apparatus according to claim 3, characterized in that said microwave generator is a single microwave generator (8) and is placed in a position below said first metal shielding means (20).

18. Instant-cooking apparatus according to claim 2, characterized in that there is provided a second metal shielding means (27A) provided with a plurality of perforations or apertures, wherein said second shielding means is interposed between said second electric heating element (15) and said top heating surface (5).

19. Instant-cooking apparatus according to claim 3, characterized in that there is provided a second metal shielding means (27A) provided with a plurality of perforations or apertures, wherein said second shielding means is interposed between said second electric heating element (15) and said top heating surface (5).

20. Instant-cooking apparatus according to claim 4, characterized in that there is provided a second metal shielding means (27A) provided with a plurality of perforations or apertures, wherein said second shielding means is interposed between said second electric heating element (15) and said top heating surface (5).