DESCRIPTION

Field of the invention

The present invention relates to a household cooking appliance, in particular an oven, having the characteristics indicated in the preamble of Claim 1. The invention likewise relates to a method for assembling fore components of a household cooking appliance, in particular an oven, according to the preamble of Claim 12.

Background of the invention

Household cooking appliances having a cooking chamber typically comprise a fixed structure, comprising a muffle, which is closed at the front by means of a door. The door is articulated in a lower area thereof to a fore part of the fixed structure of the household appliance so that it can turn about a horizontal axis.

In these appliances, the front of the appliance typically comprises also a user interface or control panel. This control panel is in general positioned above the door and includes a covering element, generally in the form of plate, where there are present the oven control means, for example keys, push-buttons, knobs, and the possible visual indicating means, for example warning lights or displays. The aforesaid covering element bears appropriate indications, for example in the form of serigraphs, for the control and/or indicating means. Frequently, this covering element is made of plastic material, with a possible further external front coating made of glass. The covering element has typically openings or through seats, for the passage of shafts for actuating control means (when these comprise rotary switches or potentiometers) or for mounting control means (such as keys and push-buttons), as well as possible indicating means (such as warning lights and displays).

In these appliances, provided between the bottom edge of the covering element and the upper edge of the door is an interstice, of a height such as to enable free angular movement of the door, without any interference with the covering element. In certain solutions, at least part of this interstice is also used as outlet opening for fumes or vapours expelled by the cooking chamber, possibly exploiting the presence of a fan outside the muffle.

For the purposes of mounting the above fore components of the appliance, the door is in general articulated to the fixed structure, after which the covering element is mounted, after the control and/or indicating means have been already mounted on the structure or on said covering element.

Fixing of the covering element to the structure of the oven is typically provided via threaded members, generally represented by stud bolts fixed with respect to squares that are glued to the back of the covering element. For the purposes of said fixing, provided on the structure of the oven, in a fore component thereof, are through holes, through which the stud bolts are made to pass. The fixing is then completed by means of nuts that are screwed to the stems of the stud bolts, the fore component of the oven thus remaining set between the nuts and the covering element.

In order to guarantee a good aesthetic and functional effect, the lower edge of the covering element and the upper edge of the door should be set aligned and parallel to one another. Also the side edges of the covering element and of the door should be set ideally aligned. To enable convenient insertion of the stud bolts in the holes provided on the fore component of the structure, the latter have a diameter slightly larger than the diameter of the stem of the stud bolts, with the position and size of the holes and of the stud bolts, as well as the position of the corresponding receiving seats on the covering element, that are established precisely in the design phase.

It happens that, on account of production or assembly tolerances of the fore element of the structure, of the door, and of the covering element there may occur misalignments between the parts in question, in particular between the facing edges of the covering element and of the door and between the side edges of the covering element and of the door. These misalignments, albeit of minimal degree, give rise to an ugly appearance of the product.

DE-A-196 49 047, upon which the preamble of claim 1 is based, discloses a household appliance, particularly an oven, with a control board having side edges which are bent rearwards and are shaped to form wings capable of engaging with corresponding pockets projecting rearwards from a frame of the household appliance. This solution is relatively complex from a manufacturing standpoint and does not solve the above mentioned problems of misalignments due to manufacturing tolerances.

Summary of the invention

The aim of the present invention is basically to overcome one or more of the aforesaid drawbacks and in particular to provide a door for a household cooking appliance, in particular an oven, where the precise mounting of its fore components, and in particular of the aforesaid covering element with respect to a door, is considerably facilitated. A further aim of the invention is to provide a method that is particularly advantageous for the purposes of precise mounting of the aforesaid fore components of the appliance.

The above and yet further aims, which will emerge more clearly hereinafter, are achieved according to the present invention by a cooking appliance, in particular an oven, and by a method for mounting fore components of a cooking appliance, in particular an oven, having the characteristics referred to in the annexed claims. The claims form an integral part of the technical teaching provided herein in relation to the invention.

Brief description of the drawings

Further characteristics and advantages of the present invention will emerge clearly from the ensuing description, with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:

- Figure 1 is a partial and schematic perspective view of a household cooking appliance according to the present invention;

- Figure 2 is a schematic and partially exploded perspective view of an upper comer portion of the appliance of Figure 1 , viewed from its rear side;

- Figures 3 and 4 are views in elevation of the portion of Figure 2, in two different assembly steps;

- Figure 5 is a front elevation of the corner portion of Figure 4, viewed from its front side.

Description of preferred embodiments of the invention

Reference to "an embodiment" or one embodiment" in the framework of this description is meant to indicate that a particular configuration, structure, or characteristic described in relation to the embodiment is comprised in at least one embodiment. Hence, phrases such as "in an embodiment" or "in one embodiment" and the like that may be present in different points of this description do not necessarily all refer to one and the same embodiment. In addition, the particular configurations, structures, or characteristics can be combined in any adequate way in one or more embodiments. The references used in what follows are only provided for convenience and do not define the sphere of protection or the scope of the embodiments. With particular reference to Figure 1 , designated as a whole by 1 is a household cooking appliance according to the present invention. In the example of embodiment exemplified, the appliance 1 is a built-in oven, but the invention must be understood as also applying to other types of cooking appliances having a front door and a generic covering fore element, above or below the door.

The oven 1 has a fixed structure, designated as a whole by 2. In the extremely schematic example illustrated, this fixed structure 2 comprises a muffle body 3, rendered fixed with respect to which, at the front, is a fore component 4, in particular a frame including at least two opposed vertical members and an intermediate cross member. In what follows, for reasons of simplicity, the fore component 4 will be identified as frame.

Hinged to the structure 2, in particular but not necessarily to the component 4, is a door designated as a whole by 5. The door 5 comprises a respective frame 6, mounted on which is a covering panel 7, for example made of glass. The door 5 is articulated at the bottom to the structure 2 so that it can turn about a substantially horizontal axis, via hinging means (not visible) of a type in itself known. Alternatively, the door 5 is articulated laterally to the structure 2 so that it can turn about a substantially vertical axis. The handle of the door 5 is not illustrated in the figures, there being visible only the corresponding fixing holes, designated by 8.

Designated as a whole by 10 is a covering element, which, in one embodiment, is mounted in a fixed position on the structure 2, above the door 5. In the preferred embodiment, as is the one shown, the covering element 10 provides the front face of a user interface or control panel. As regards the covering element 8 not illustrated either are the control means and/or the indicating means of said panel, but just two openings 13 are highlighted, merely by way of example, for passage of drive shafts belonging to respective control means of the oven (not represented) for example rotary selectors. Obviously, the control panel can comprise more than two control means and/or also visual warning elements, in which case the covering element 10 possibly envisages other openings or through seats. The control means may also be of the touch type, in which case it is not necessary to provide the element 10 with the openings 13 represented in the figures.

In the example of embodiment illustrated, the covering element 10 includes a main body 1 1, preferably formed by moulding of thermoplastic material, having a front wall 1 l a on which there is applied, for example via gluing, a plate 12 having an aesthetic purpose. This plate 12 may, for example, be made of glass and bear indication serigraphs for the control and/or indicating means of the control panel (not represented).

Defined between the lower edge of the covering element 10 and the upper edge of the door 5, when this is closed, is an interstice, designated in Figure 1 by G. In a preferred embodiment, the interstice G, in addition to having the function of enabling free movement in opening and closing of the door 5, without any interference with the element 10, is exploited at least in part as outlet for fumes or vapours expelled from the muffle 3. In one embodiment, the interstice G has for this purpose a height of approximately 4 mm.

In the case where the appliance 1 is provided with a system for cooling the door, aimed at generating (for example, via the action of a tangential fan) a flow of cooling air through an internal gap to the door 5, the interstice G may also be exploited for supply or discharge of the cooling air: in this case, the height of the interstice G should preferably be more than 4 mm, for example approximately 8 mm or else approximately 14 mm in the case where the appliance 1 is a pyrolytic oven.

With particular reference to Figure 2, a portion of the fore element may be seen from the rear side thereof. In said figure, also partially visible is the back of the door 5. In the example, the frame 4 comprises at least two vertical side members, only one of which may be seen and is designated by 4a, and at least one cross member, preferably two cross members, just one of which is visible and is designated by 4b. In one embodiment, the upper cross member 4b is in a position intermediate between the two ends of the vertical member 4a.

As explained previously, in a cooking appliance of the type considered herein the door 5 and the covering element 10 must be set mounted with respect to the fixed structure 2 in such a way that, in the conditions of closing of the door 5, defined between the lower edge or wall of the covering element 10 - designated by 10a - and the upper edge 5a of the door 5 - designated by 5a - is the interstice G of Figure 1. Moreover designated by 10b and 5b in Figure 2 are a lateral edge or wall of the covering element 10 and a lateral edge 5b of the door 5, respectively.

The covering element 10 is secured in a fixed position to the frame 4 via fixing means, which include threaded members 18, typically represented by screws having a head 18a and a threaded stem 18b. According to a characteristic of the invention, the fore component or frame 4 of the structure 2 and the covering element 10 are provided with means for mutual hooking, which comprise first hooking means on the frame 4 and second hooking means on the covering element 10, where the first and second hooking means are pre-arranged to provide between them a loose or slack coupling with

Play- According to another characteristic of the invention, the means used for fixing the covering element 10 on the fore component or frame 4 are provided to enable the covering element 10 to be secured in one of a plurality of possible alternative positions, allowed by the play existing between the aforesaid first and second hooking means.

As will emerge more clearly hereinafter, according to a preferential characteristic of the invention, the aforesaid means for mutual hooking are designed to support the covering element 10 on the component or frame 4, in the respective condition of loose coupling, also before the element 10 is definitively fixed in the corresponding fixed position, obtained via the aforesaid fixing means.

According to another preferential characteristic of the invention, the aforesaid means for mutual hooking are configured to enable play in more than one direction of the covering element with respect to the front element, in particular at least in a generally vertical direction and in a generally transverse direction, to enable:

- an alignment of the lower edge 10a of the covering element 10 with respect to the upper edge 5a of the door 5, with the two aforesaid edges at a distance apart and parallel to one another for defining the interstice G; and

- an alignment of a lateral edge 10b of the covering element 10 with respect to a lateral edge 5b of the door 5.

As may be seen in Figure 2, in one embodiment the first hooking means comprise at least one tongue, projecting frontwards from a front of the frame 4, designated by 14. On the other side, the second hooking means comprise at least one seat for engagement with play of the tongue 14. This engagement seat, designated by 15, is defined like a pocket on the back of the covering element 10, in particular in the front wall 1 1 a of the body 1 1 thereof. In the embodiment exemplified, the body 1 1 is made of moulded thermoplastic material and the seat 15 is made integrally in the back of the wall 1 l a thereof. In the example, said seat 15 basically consists of a projection or embossing of the rear surface of the wall 1 1 a of the body 1 1 , which is hollow and open at the bottom in order to enable insertion of the tongue 14. In the embodiment exemplified in the figures, the tongue 14 generally faces upwards and extends substantially parallel to a front surface of the frame 4: it will, however, be appreciated that the tongue 14 might also be possibly slightly inclined.

It should be pointed out that a reverse arrangement of the hooking means is also possible, i.e., with the tongue 14 on the back of the wall 1 la of the body 1 1 and with the seat 15 on the front of the frame 4. In one such configuration, the tongue on the body 1 1 will be set projecting downwards, whilst the seat 15 will be open upwards.

Once again with reference to Figure 2, the fixing means used for securing the covering element 10 to the frame 4 in a fixed position comprise a plurality of openings, formed in the front of the frame 4. Highlighted in Figure 2 are two of said through openings, designated by the reference 16, which have a diameter, or in any case a cross-sectional dimension, larger than the section of the stem of the threaded members used for fixing. On the other side, i.e., on the covering element 10, the fixing means include a plurality of seats 17 for receiving an end portion of the stem of the aforesaid threaded members. In Figure 2, the aforesaid receiving seats are designated by 17, whilst the threaded members, here represented by screws advantageously having the peculiarity of being self-tapping, are designated by 19, with the corresponding head 1 8a and the corresponding stem 18b.

In the example of embodiment exemplified, the seats 17 are defined by projections 19, which project from the rear surface of the wall 1 l a of the body 1 1 and have one end that, in the fixed condition of the covering element 10, bears upon the front surface of the frame 4 that surrounds the respective through opening 16. Each seat 1 7 defined in the projections 1 9 has cross-sectional dimensions coinciding with the diameter of the threaded stem 18b of the screws 18, and hence smaller than the cross-sectional dimensions or diameter of the through openings 16. Obviously, also the ends of the projections 19 that bear upon the frame 4 have cross-sectional dimensions larger than those of the corresponding openings 16 so that there can be generated appropriate mating between the projections 19 and the frame 4. In one embodiment, as in the case illustrated, each opening 16 is formed in the bottom of a respective depression of the frame 4, here of an approximately circular shape, having cross-sectional dimensions larger than the aforesaid ends of the projections 19 to enable the necessary play between the parts. These depressions, when present, contribute to facilitating positioning between the parts in the assembly phase.

The frame 4 has two opposite side regions, where the covering element 10 is fixed in two respective opposite side regions via the aforesaid fixing means 16- 19: in Figure 2 just one of these side regions of the frame 4 (basically corresponding to the upright 4a) and of the covering element 10 may be seen, it being understood that the opposite regions are made in a similar way.

Preferably, each of the aforesaid side regions of the frame has two through openings 16, in a position set on top of one another, and each side region of the covering element 10 has two receiving seats 17, in particular with the respective projections 19 in a position set on top of one another, with the first and second hooking means that are arranged in an intermediate position between the openings 16 and the seats 17. Consequently, with reference to the example of embodiment illustrated, the tongue 14 is located between the two through openings 16, whilst the seat 1 5 is located between the two seats 17.

As has been said, very advantageously, in an embodiment as the one represented, the body 1 1 is made of moulded thermoplastic material so as to integrate both the corresponding fixing means, i.e., the receiving seats 17 or the corresponding projections 1 9, and the corresponding hooking means, i.e., the seats 1 5. In one such embodiment, the fixing screws 18 are preferably self-tapping screws. It is to be noted that the threaded fixing members might also be of a type different from the one exemplified (for example, bolts and nuts), even though this might complicate assembly.

The methodology of mounting of the components illustrated previously, and in particular of the covering element 10, is very simple and enables the typical problems of the prior art to be overcome.

In the production phase, the fixed structure 2 is provided, which comprises the frame 4, and the door 5 is assembled separately, according to a technique in itself known. Likewise obtained is the covering element 10, which, as has been said, preferably comprises a body 1 1 made of moulded thermoplastic material so as to define the various functional elements described previously, to which the plate 12 will then be applied at the front, for example by gluing.

Next, the door 5 is articulated to the fixed structure 2, with modalities in themselves known. For this purpose, known hinges can be used, which are fixed between the frame 6 of the door and, for example, the frame 4, in a lower region of the latter. After mounting and alignment of the door with respect to the frame 4, secured in a fixed position to the structure 2, i.e., to the frame 4, is the covering element 10.

As already explained previously, mounting of the door 5 and of the covering element 1 0 on the structure must be such that, in the condition where the door is closed, the lower edge 10a of the covering element 10 is at a distance from the upper edge 5a of the door 5 so as to define the interstice G, with the two edges that are parallel to one another.

According to the invention, and as already explained previously, the frame 4 is provided with the first hooking means, which in the example illustrated are represented by the tongues 14, and the covering element 10 is provided with the second hooking means, represented in the example by the seats 15. As has been seen, these first and second hooking means can be coupled together in a loose way with play. Likewise, the fixing means 16- 19 are provided for the purposes referred to previously, i.e., so as to enable the covering element 10 to be secured in a fixed position on the frame 4 in one of a plurality of possible alternative positions, which are allowed by the play existing between the hooking means 14- 1 5.

It should therefore be pointed out in this regard that the width of the tongue 14 is smaller than the width of the cavity of the seat 15 in such a way that - in the condition where the two tongues 14 are coupled to the corresponding seats 15 - the covering element 10 can be displaced manually to the right and to the left with respect to the frame 4, in the condition of loose coupling of the hooking means. It should likewise be pointed out that the vertical development or the development in height of the tongue 14 is smaller than the homologous dimension of the seat 15 so as to enable - once again in the condition of loose coupling - a substantial displacement also in a vertical direction, without this bringing about disengagement between the tongues and the seats.

For the purposes of assembly the covering element 10 is coupled in a loose way to the frame 4, via the coupling of the hooking means provided between the two parts in question, i.e., the tongues 14 and the seats 1 5. In this condition the covering element 10 is already supported on the frame 4, even though the final fixing has not yet been carried out. This facilitates the operations that the operator responsible for assembly must perform, in so far as he does not have to support the covering element 10 in position manually. At this point, and if necessary, the operator can displace the covering element 10 with respect to the frame 4, until the desired final fixing position is identified. This final fixing position can be identified by the operator from among a plurality of possible alternative positions, which are allowed, on the one hand, by the play defined by the hooking means 14- 15 and, on the other hand, by the fact that a play is also possible between the fixing screws 1 8 and the through openings 16 (as has been said, in fact, the cross section of the stem 18b of the screws 1 8 is decidedly smaller than the diameter of the through openings 16). In practice, the operator can displace to the right or to the left, upwards or downwards the covering element 10, albeit in the condition of loose coupling with the frame 4, until the desired position of alignment of the edges 10a, 5a 10b, 5b is identified. Once this position has been identified, the operator proceeds to the final fixing, via the screws 18. These screws 1 8 are screwed from the rear side of the frame 4 (i.e., from the position visible in Figure 2), with the screws 1 8 that are inserted through in the openings 16 and their tip portion that screws into the seats 17 of the projections 19. The heads 18a of the screws 1 8 bear upon the surface that surrounds the openings 16, in the rear part of the frame 4. By tightening the screws, the head surface of the projections 19 approaches the front surface of the frame 4, until they bear upon it, in the area surrounding the openings 16. When the screws 1 8 are tightened down final fixing in position is obtained.

For a clearer picture of assembly reference may be made to Figures 3 and 4. Figure 3 illustrates a first step of hooking with loose coupling, where the covering element 10 is engaged to the frame 4, via the tongues 14 and the seats 1 5. In said condition, the vertical engagement between the tongues and seats is maximum, in the sense that the bottom edge of the seats 15 bears upon the stretch of the tongues 14 that is substantially orthogonal or transverse to the front surface of the frame 4. As may be noted in Figure 3, in said condition, the distance between the lower edge 10a of the element 10 and the upper edge 5a of the door is minimum. From Figure 3 it may moreover be noted how, in said condition, the seats 17, or else the projections 19, are in a first position with respect to the openings 16.

At this point, as has been said, the operator can displace the element 10, exploiting the play allowed by the hooking means 14- 15 and by the fixing means 16- 19, for locating the position deemed optimal for final fixing. Figure 4 highlights such a positioning, which, merely by way of example, shows the receiving seats 17 centred with respect to the openings 16. As has been said, this is a condition illustrated purely by way of example, in so far as the alignment between the edges 10a and 5a could be obtained also with a different relative position between the seats 17 and the openings 1 6, in the limits allowed by the play existing between the parts.

In the preferred embodiment of the invention, the hooking means 14- 15, the dimensions of the through openings 16, and the diameter of the stems 18b of the screws 18 is chosen preferably to enable play in more than one direction (up, down, right, left, diagonal) of at least 2 mm in each direction: in said perspective, for example, the openings 16 can have a nominal diameter of 8 mm (when they are circular in shape, as illustrated) whilst the cross section of the stem 1 8b of the screws 1 8 will have a nominal diameter of 4 mm.

The hooking means constituted by the tongues 14 and by the seats 15 can enable also a slight play in a front direction. As may be readily understood, when the screws 1 8 are tightened a slight displacement of the covering element 10 is obtained towards the front surface of the frame 4; on the other hand, even in the absence of play in a front direction tightening of the screws 18 can be such as to cause a bending or deformation of the tongues 14 backwards.

In a particularly advantageous embodiment of the method according to the invention, the operation of identification of the fixing position deemed optimal is carried out by the operator using at least one positioning template. One such template is designated as a whole by 20 in Figure 5.

Preferably, the template used is configured to enable an alignment or parallelism between the lower edge 10a of the covering element 10 and the upper edge 5a of the door 5, with the two aforesaid edges at a distance apart from one another to define the interstice G, as well as an alignment of a lateral edge 10b to the covering element 10 with a lateral edge 5b of the door.

In the example of embodiment of Figure 5, the template 20 comprises for this purpose two portions 21 and 22 generally orthogonal to one another. The portion 21 has a predefined thiclcness substantially corresponding to the height of the desired interstice G. This portion 21 has two opposite faces, designated by 21 a and 21 b, designed to come into contact with the edges 10a and 5a, respectively. The second portion 22 has two coplanar surfaces 22a and 22b, designed to come into contact with the lateral, edge 1 0b and the lateral edge 5b of the element 10 and of the door 5, respectively.

As may be readily understood from Figure 5, by inserting the template 20 in the position illustrated, it is possible to obtain easily alignment of the edges 10a and 5a and alignment of the edges 10b and 5b. In the example illustrated, the template 20 comprises the portions 21 and 22 corresponding only to a side region of the ensemble constituted by the door 5 and the covering element 10, but obviously a template could be conceived to enable simultaneous alignment at both sides, i.e., with portions 21 and 22 specular to those visible in Figure 5.

The invention has been described previously with reference to a covering element for a user interface, which is positioned above the door of the cooking appliance. It will be appreciated, however, that the same idea can be adopted also in the case where a user interface is positioned underneath the door of the appliance, there remaining understood the need to provide a interstice G, in this case between the upper edge of the covering element and the lower edge of the door. An embodiment of this sort is, for example, indicated in the case of built-in ovens for in-column installation, where it may prove convenient to provide the user interface underneath the door, in a position that for certain end users can be considered more advantageous from the ergonomic standpoint.

Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary with respect to what is described and illustrated herein purely by way of example, without thereby departing from the scope defined by the ensuing claims.

Finally, the present invention could find application on other electrical household appliances having a door and a front control panel, such as for example dishwashers.