Cooking hob for cookers with radiating electric plates

Abstract: A cooking hob for cookers with radiating electric plates comprises a metal sheet (20) wherein at least one housing (1) is formed for a respective radiating electric plate (2); said housing (1) consists of an area of the metal sheet (20) drawn to form a cup (3), with shape and dimensions substantially corresponding to those of the radiating plate (2).

Description: The present invention relates to a cooking hob for cookers with radiating electric plates. Known cooking hobs for cookers with radiating electric plates consist of metal sheets, and provide housings for the radiating plates consisting of circular holes with a diameter substantially corresponding to that of the plates which have to be housed therein. The edges of these holes are drawn and have substantially vertical walls. The radiating plate, provided with a flange with a slightly larger diameter compared to the body of the plate, rests on said walls of the hole. The plate is attached by means of a cup-shaped counterflange provided with a central hole for the passage of a bolt screwed to the radiating plate. The counterflange is mounted on the lower surface of the cooking hob, and is attached to the plate by means of a tightening nut. The counterflange also consists of a metal sheet, but with greater thickness compared to the cooking hob, to prevent it from deforming when the fastening nut is tightened onto the bolt of the radiating plate. The main disadvantage of these cooking hobs lies in the fact that, having to provide one or more holes of considerable diameter, they lose some of their rigidity, becoming subject to deformations caused by temperature gradients. This problem, which is more marked when the cooking hob is small and the more electric plates it has to house, already appears during the operation of enamelling (performed hot), causing cracks in the enamel film during subsequent cooling. The problem also occurs again while the cooker is being used. A second disadvantage lies in the complexity of the manufacturing process, which has to include moulding of the metal sheet to form the holes, trimming of the edges of said holes and drawing of the sheet to give it the required shape. The metal sheet forming the counterflange, being of greater thickness, has to be drawn separately. It should also be taken into account that the part of the sheet which is removed to form the holes cannot be reused, thus leading to a waste of material. A further problem consists of the laborious efforts involved in mounting the radiating plates on the cooking hob: before screwing the fastening nut of the counterflange, both the radiating plate and the respective counterflange must in fact be centered in the housing hole. Since, for reasons of time, the operator in charge of assembly cannot additionally orientate the radiating plate angularly in the respective housing so that the respective electric supply terminals are arranged in a predefined position, it is not possible to include an automatic wiring operation. In practice the wiring layout is designed in order to adapt to the variable position of the electric terminals of the plates. AT-B-123 135 discloses a portable electric cooking plate as defined in the preamble of claim 1. In view of the state of the art described, the object of the present invention is to provide a cooking hob for cookers with radiating electric dates which is unaffected by the aforementioned problems. In accordance with the present invention, this object is achieved thanks to a cooking hob as defined in claim 1. Thanks to the present invention it is possible to provide a stronger cooking hob, whose production only requires operations of drawing and not moulding nor trimming of holes, as is however the case for known cooking hobs. The cooking hob is thus less subject to torsions during the machining phase, and has properties of greater rigidity which reduce heat deformations. It is no Longer necessary to provide separate parts which, being of different thicknesses, have to be moulded and drawn separately, and complicate the operations of assembly: the latter are instead simplified, since positioning of the radiating plate in the respective housing is immediate, and it is not necessary to pay attention to centering. The features of the present invention will be made clearer from the following detailed description of one of its embodiments, illustrated by way of a non-limiting example in the accompanying drawings, in which: Figure 1 is a sectioned view along line I-I of Figure 2, of a part of a cooking hob according to the present invention wherein a housing is obtained for a radiating electric plate; Figure 2 is a plan view of said cooking hob part; Figure 3 is a sectioned view similar to that of Figure 1, after assembly of a radiating electric plate. A cooking hob according to the present invention consists of a metal sheet 20, appropriately shaped by means of drawing operations. Said cooking hob may house only radiating electric plates or radiating electric plates in combination with gas burners. Figures 1 and 2 show a part of a cooking hob according to the invention wherein a housing 1 is formed for a radiating electric plate 2 (which can be seen in section in Figure 3). The housing 1 is obtained by drawing of the metal sheet 20, and comprises a cup 3, for example circular, whose base 6 is lowered in relation to the surface 4 of the cooking hob. The edges 5 of the cup 3 are instead raised in relation to the surface 4 of the cooking hob to form a support crown 21. A circular projection part 8 is formed on the base 6 of the cup 3 and again obtained by drawing of the sheet 20, which projection surrounds a lowered circular area 9 in the centre whereof a central through hole 7 is provided. An opening 10 (in the shape of a circular crown segment) is also provided on the base 6 of the cup 3 for the passage of electric contacts 11 of the radiating plate 2 (Fig. 3). Again on the base 6 of the cup 3, two through holes 12 are formed (Fig. 2) for housing respective pins 13 with which the radiating plate 2 is provided in order to facilitate correct positioning of the same (Fig. 3). The base 6 of the cup 3 is therefore substantially closed, with only the minimum necessary number of openings for electric connection and attachment of the radiating plate 2 being formed therein. As can be seen, the position of the electric terminals 11 is predefined and depends on the position of the opening 10. This allows the wiring layout design to be optimised: in the case wherein the cooking hob has to house several radiating plates 2, the wiring layout can for example be designed so as to take into account distribution of temperature on the cooking hob. The wiring operation can also be performed automatically. Since also the electric terminals are to be found below the cooking hob, they are insulated thermally. The radiating plate 2 comprises, in a manner in itself known, a base 22, an intermediate circular flange 16 and an upper radiating disk 23. At the bottom of the base 22 the electric terminals 11 are connected, with a threaded tie rod 15. The circular flange 16 has a diameter which is slightly Larger than the base 22. For installation the radiating plate 2 is placed in the cup 3 and oriented so that the pins 13 are inserted in the respective holes 12 provided on the base of the cup 3 itself. In this position, the electric terminals 11 project below the sheet 20. The circular flange 16 rests on the support crown 21. The radiating plate 2 is attached by screwing a nut 14 on the threaded tie rod 15, which projects from the hole 7.

Claims: Cooking hob for cookers with radiating electric plates, comprising a metal sheet (20) wherein at least one housing (1) is formed for a respective radiating electric plate (2), said housing consisting of a cup (3) with shape and dimension substantially corresponding to those of the radiating electric plate (2) and having a base (6) provided with an opening (10) for the passage of the electric terminals (11) of the radiating electric plate (2), characterized in that said cup (3) is formed by an area of the metal sheet (20) which is drawn to form a cup (3), said base (6) consisting of a substantially closed metal sheet plane which is provided with a central through hole (7) for the passage of a threaded tie rod (15) integral with the radiating plate (2) for supporting and fixing the electric radiating plate (2) to the base of the cup (3) and has said opening (10) for the passage of electric terminals (11) which is arranged between said central through hole (7) and the periphery of said base. Cooking hob according to claim 1, characterised in that said area drawn to form a cup (3) is surrounded by an annular drawn area (21) of the metal sheet (20), projecting in relation to an upper surface (5) of the cooking hob to form a support for a flange (16) of the radiating plate (2).

Inventors: FUMAGALLI SILVANO, FUMAGALLI, SILVANO
Applicants: CANDY SPA, CANDY S.P.A.
Application year: 1995
Main classification: H05B3
IPC codes: H05B3