Method for manufacturing a household cooking appliance, and corresponding household cooking appliance

A method for manufacturing an oven includes a) providing the muffle defining a cooking chamber (5); b) providing a channelling (10) for conveying air; c) associating to a rear wall (5c) of the muffle (5) a first fan (30) for ventilation of the cooking chamber; d) associating to the channelling (10) a second fan (20) for forcing air into the channelling (10); e) associating the channelling (10) to an upper wall (5a) of the muffle (5). Step b) comprises shearing from a semi-finished product of a metal component (10a) of the channelling (10) a corresponding portion (40), so as to define an opening (23) for installation of the second fan (20). Step c) comprises using the portion (40) sheared from the semi-finished product of the metal component (10a) of the channelling (10) as a bracket for fixing the first fan (30) to the rear wall (5c) of the muffle (5).

TEXT OF THE DESCRIPTION

Field of the Invention

The present invention relates to household cooking appliances and to the corresponding manufacturing methods. The invention has been developed with particular reference to cooking appliances comprising a cooking chamber, defined by a muffle, and a channelling for conveying air, which extends over an upper wall of the muffle.

Prior Art

Appliances of the type referred to above are known and are typically constituted by cooking ovens or kitchen ranges comprising a cooking oven and include a metal load-bearing structure associated to which are the muffle, which delimits the cooking chamber, and a corresponding front door.

In some ovens, the muffle has, in an area corresponding to its upper wall, a flue for expulsion of fumes from the cooking chamber, and extending over this upper wall is a channelling into which the flue gives out. The channelling, which is generally formed in one or more parts of sheet metal, is shaped so as to have a corresponding outlet at the front of the appliance. Some of these ovens also comprise a second fan, associated to a rear end of the channelling so as to force an air/fume mixture along the channelling itself and expel it from its outlet, on the front of the appliance. The fan used is typically a tangential fan with horizontal axis, which, in some solutions, has a volute defining an air intake, for taking in air from inside the structure of the appliance, generally from an area behind the rear wall of the muffle. The channelling may also be divided into a delivery duct, for the aforesaid air/fume mixture, and a duct for intake of air from outside, which extends underneath the delivery duct and has an inlet at the front of the appliance, substantially at the upper portion of the door, but underneath the outlet of the delivery duct.

In some cases a channelling of the type indicated above is used—not necessarily in combination with a flue—for inducing flows of cooling air into one or more gaps of its front door, in particular when the appliance has functions of pyrolytic cleaning of the cooking chamber.

It is then known that, in ovens of a ventilated type, generally provided inside the muffle is a metal partition wall, mounted in a position facing the rear wall of the muffle itself. This partition wall divides the internal cavity of the muffle into a front cooking chamber, which extends between the door and the partition wall, and a rear air-distribution chamber, which extends between the partition wall and the rear wall of the muffle. Operatively set in this air-distribution chamber are at least one rear heating resistance, which usually has a circular shape, and the impeller of a centrifugal fan, which is usually positioned within a region circumscribed by the resistance. The motor of the fan, with a corresponding support, is mounted on the outside of the rear wall of the muffle.

In general, the support of the motor is mounted on a quadrangular bracket, which is fixed to the rear edges of two side walls of the load-bearing structure of the appliance. An intermediate region of the quadrangular bracket is set up against and fixed to the rear wall of the muffle. In this intermediate region, the quadrangular bracket has a through hole aligned to a through hole of the rear wall of the muffle, for the shaft of the motor of the fan, fitted on which is the corresponding impeller.

This type of embodiment is relatively laborious as a result of the need to fix the quadrangular bracket both to the load-bearing structure of the appliance and to the rear wall of the muffle and entails a significant use of metal material to produce the bracket.

SUMMARY OF THE INVENTION

In view of what has been set forth above, the object of the present invention is to provide a cooking appliance, including a ventilated cooking cavity and a channelling for conveying air, that is extremely simple and inexpensive to manufacture.

The above object is achieved, according to the present invention, by a method for manufacturing a cooking appliance and by a cooking appliance that present the characteristics indicated in the annexed claims.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Reference to “an embodiment” or “one embodiment” in the framework of the present 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 various points of this description do not necessarily refer to one and the same embodiment of the oven forming the subject of the invention. In addition, particular conformations, structures, or characteristics may be combined in any adequate way in one or more embodiments, even different from the ones represented. The references used herein are only provided for convenience and hence do not define the sphere of protection or the scope of the embodiments. Moreover, the cooking appliance will be described in what follows limitedly to the elements necessary for an understanding of the invention, it being taken for granted that it includes all the other components normally known and necessary for its operation.

With initial reference toFIG. 1, designated as a whole by1is a household cooking appliance according to the invention, represented herein by a built-in oven. The invention may in any case be applied also to free-standing ovens and kitchen ranges integrating an oven. The oven1has a load-bearing structure or body, designated by2, associated in a stationary way to the front of which is a control panel3. Also associated to the front part of the body2is a front door4, which in particular is hinged in a lower region thereof and is provided with a handle4a. The structure of the door4, which is preferably at least in part made of metal, may comprise a plurality of door panels, just one of which is designated by4b, which define between them a series of cooling chambers. The lower edge of the control panel3and the upper end of the door4are separated from one another by a space or gap, designated by G. The presence of this gap prevents the panel3from constituting a hindrance to opening of the door itself and—as will emerge hereinafter—enables passage of at least one flow forced by a fan.

Housed inside the body2is a muffle, designated as a whole by5inFIG. 2, which may be made of a single piece or of a number of parts fixed together, made of sheet metal. The muffle5has a rigid metal body, for example obtained from sheet metal, which has an upper wall, a lower wall, a rear wall, and two side walls (just one of which is visible), designated by5a,5b,5cand5d, respectively. The muffle5is preferentially thermally insulated via an insulating cladding, of a conception in itself known and not represented. The body of the muffle5defines a cooking cavity (not visible), which can be opened and closed at the front by means of the door4ofFIG. 1. For this purpose, associated to the muffle5are means (not visible either) for heating the cooking cavity, which comprise, for example, a circular rear resistance, as mentioned in the introductory part of the present description.

Designated as a whole by10is a channelling for conveying air, with a fan20associated thereto, provided with a corresponding electric motor21and a support22. The channelling10may form part of a system for extracting fumes from the muffle. In addition or as an alternative, the channelling10may form part of a system for cooling the door4, when the latter has one or more cooling chambers. The channelling10preferentially includes at least one delivery duct, the outlet of which is located at the front of the appliance1. On the other hand, the channelling10may define both an intake duct and a delivery duct set on top of one another, with the inlet of the latter at the front of the appliance. The channelling preferentially has a generally tapered shape, starting from its front part towards its rear end region, where the fan20is mounted.

The channelling10is associated to the upper wall5aof the muffle5and preferably extends over the upper wall so that its front part, here having a width roughly corresponding to the width of the muffle5, is located in the proximity of the gap G and of the upper portion of the door4. The fan20is mounted at an opening (not represented herein) of the upper wall of the channelling10, present in the rear region of the latter. In the non-limiting example illustrated, the channelling10is made up of two components coupled together, designated by10aand10b, obtained by pressing of sheet metal and basically configured as half-shells.

To the outer side of the rear wall5cof the muffle a fan30is associated by means of a corresponding supporting bracket40provided according to the present invention, which is preferentially disk-shaped. As will emerge more clearly hereinafter, the bracket40is made of the same sheet metal and has the same thickness as the component10aof the channelling10.

Clearly visible inFIG. 3is the fan30, comprising a corresponding electric motor31and a support32, which defines respective fixing appendages, some of which are designated by32aand which are provided with a through hole. The appendages32aare positioned within respective positioning seats41, preferably seats recessed towards the rear wall5cof the muffle5, which are defined in the disk-shaped bracket40. The bracket40moreover defines a series of positioning protrusions or projections, designated by42. These projections42, which are also preferably recessed towards the rear wall5cof the muffle5, are brought up against and fixed to respective protrusions or projections6projecting from the above rear wall5c.

The shaft31aof the motor passes through respective holes of the bracket40and of the rear wall5cof the muffle in order to project into the cavity of the latter. Fitted to the end of the shaft31a(not visible) is a centrifugal impeller (not visible), which is for example located in the area circumscribed by the rear circular resistance referred to previously. As per the known technique, on the inside of the muffle5there may be provided a partition wall, which divides its cavity into a front cooking chamber and a rear air-distribution chamber, where the above resistance and impeller are located.

Visible inFIG. 4is just the body of the muffle5, defined in the upper wall5aof which is a fume outlet7. The fume outlet7comprises a through hole or through opening of the upper wall5a, which is preferentially defined in a central area of the wall itself. In the embodiment exemplified inFIG. 2, this fume outlet7is connected to a respective inlet defined in the lower component10bof the channelling10. Once again visible inFIG. 4is the rear wall5cof the muffle, defined in the central area of which are the projections6, for example three projections arranged substantially at approximately 120° from one another. In a central position with respect to the projections6, the wall5chas a through hole8for the shaft31aof the motor31of the fan30(FIG. 3).

The projections6, which preferentially have a generally plane top, are provided with corresponding through openings6a. In a preferred embodiment, these openings6aare substantially quadrangular in order to enable installation of corresponding clips9, as may be seen inFIG. 5and in the corresponding detail ofFIG. 6. These clips9, provided with corresponding threaded through holes9aor having an associated nut, are used for fixing the bracket40to the rear wall5cof the muffle, via threaded means, for example screws. In a different embodiment, on the other hand, the openings6aare configured as simple through holes for receiving respective threaded fixing means, for example self-tapping screws.

Visible in top plan view inFIG. 7is a semi-finished product, designated by10a′, from which it is possible to obtain the upper component10aof the channelling10. The component10a, and hence the semi-finished product10a′, is obtained from sheet metal of a given thickness via pressing and shearing operations.

In a step of pressing of the semi-finished product10a′, for example with a suitable punch, an impression is defined that reproduces the shape of the support40, including the seats41, the projections42, and a through hole for passage of the shaft of the motor31, this impression being designated as a whole by A inFIG. 7. The impression A is made at the area where the fan20of the channelling10is to be installed, in the rear region of the semi-finished product itself, and hence of the component10a. Next, the part including the impression A is sheared from the semi-finished product10a′, thus obtaining simultaneously the bracket40and an opening for installation of the fan20.FIG. 8is a schematic illustration of the result of the aforesaid shearing operation, which enables the component10aof the channelling to be obtained, with the respective opening23—here circular—for installation of the fan20, as well as the supporting bracket40for the fan10. Evidently, in this way, the bracket40and the component10awill be made out of one and the same sheet material of the same thickness.

The bracket40is visible in different views inFIGS. 9 and 10, with the respective positioning seats41and positioning protrusions or projections42, provided with the corresponding end holes or openings. In a central area with respect to seats and projections (which here are both three in number, arranged at approximately 120° from one another) the aforesaid central through hole is present, designated by43, for the shaft31aof the fan30.

As may be seen inFIGS. 9 and 10, in a possible embodiment the bracket40comprises further positioning seats44, for example four seats, for use in the case where the support of the motor31is provided with appendages or bayonet fittings. In the example represented, the seats44are through seats obtained by shearing around the central hole43. The seats44may be provided in addition or as an alternative to the seats41. In the case where the seats41are not envisaged and the support for the motor is provided with appendages or bayonet fittings, the bracket40may include through holes (some of which are visible but are not designated by references) in the area of the seats44, to secure the support for the motor to the bracket also with screws.

FIG. 11represents a subsequent step of production of the cooking appliance, where the bracket40is mounted on the rear wall5cof the muffle5. For this purpose, the projections42of the bracket40are brought up against the projections6projecting from the rear5aso that they can be fixed there via screws that engage the holes9aof the clips ofFIG. 6. Following upon this fixing operation, the central hole8(FIG. 5) of the wall5cof the muffle5and the central hole43of the bracket40are aligned to one another. As has been mentioned, the projections6could also be provided with simple through holes, where the protrusions42can be fixed via self-tapping screws.

After installation of the bracket40as represented inFIG. 11, the shaft31aof the motor31is inserted through the aligned holes8and43, making sure that the fixing appendages32aof the corresponding support32(FIG. 3) are aligned with the respective seats41of the bracket40. At this point, the support32of the motor31can be fixed to the bracket40via threaded means that engage the holes of the seats41and of the appendages32a, for example bolts or self-tapping screws. Obviously, fixing of the support32to the bracket40may be carried out also before fixing of the latter to the rear wall5cof the muffle5. In the case where the support of the motor envisages a bayonet coupling with the bracket40, the seats44described just above can be exploited.

Once this fixing operation is completed, the impeller of the fan30can be associated to the corresponding shaft31a, on the inner side of the muffle5.

The perimetral dimensions or the diameter of the bracket40do not necessarily correspond exactly to the perimetral dimensions or to the diameter of the opening23. The dimensions may differ on account of machining tolerances and residue, or else may differ in the case where the bracket40is to be provided with a peripheral rim bent back. In general terms, the perimetral dimensions of the bracket40are comprised between 80% and 100% of the perimetral dimensions of the opening23, preferably comprised between 85% and 95%, very preferably comprised between 88% and 92%.

In the solution according to the invention, the fan20is a radial fan having a centrifugal impeller. The corresponding support22, which is preferably made of metal and here has a generally annular configuration, is coupled and fixed to the component10aof the channelling at the opening23ofFIG. 8. Preferentially, the diameter of the opening23is greater than the diameter of the impeller of the fan20in order to enable easy insertion of the latter within the channelling10, in the production stage. Preferentially (seeFIG. 2), the support22has an annular peripheral part, which rests and is fixed substantially along the rim of the opening23, and a series of substantially radial uprights for supporting the motor21of the fan20on the outside of the channelling10. The annular part of the support22is fixed around the opening23preferably via threaded means or rivets, possibly with the aid of brackets. The motor21has a single shaft that identifies the axis of rotation of the centrifugal impeller and that projects down from the body of the motor21for supporting the impeller itself in a rotatable way within the channelling10. The channelling10then has at least one air intake. In the example, the support22has a structure that is partially annular and partially spoked so as to define a series of passages (not shown), which, together with the opening23of the component10a, provide an upper air intake. Use of the radial fan20, among other things, affords the advantage that the channelling10itself can provide the volute for the centrifugal impeller20: for this purpose, as highlighted for example inFIG. 2, the rear end region of the channelling10has a generally arched peripheral profile.

The channelling10, when it is equipped with the corresponding fan, can be associated to the upper wall5aof the muffle5, for example via brackets associated to the body2ofFIG. 1, in such a way that a lower inlet thereof, defined in the component10b(FIG. 2), will be located in a position corresponding to the fume outlet7.

From the foregoing description, the characteristics of the present invention emerge clearly, as likewise do its advantages. The solution according to the invention enables simplification of fixing of the rear fan, without any need for anchorages also to the load-bearing structure of the appliance. The bracket can be of contained dimensions, with consequent significant saving of material. Advantageously, moreover, the bracket is obtained from a part that must in any case be sheared from a different component, i.e., a component of the channelling for conveying the air, with consequent further saving in terms of materials used and machining operations.

It is clear that numerous variations may be made by the person skilled in the branch to the cooking appliance described by way of example, without thereby departing from the scope of the invention as defined by the ensuing claims.