EP0697083B1 - Domestic oven - Google Patents

Abstract

PCT No. PCT/FR94/00494 Sec. 371 Date Oct. 26, 1995 Sec. 102(e) Date Oct. 26, 1995 PCT Filed Apr. 29, 1994 PCT Pub. No. WO94/27092 PCT Pub. Date Nov. 24, 1994The oven comprises a housing (1) enclosing an open cavity (4) which is closed by a door (6) pivotally mounted about a horizontal shaft (8) placed in the housing. The cavity includes a food-carrying tray (5) horizontally translatable via at least one motion transfer mechanism (10) controlled by the door. The motion transfer mechanism (10) includes several transmission stages, each consisting of a notched belt (12;23) meshing with two toothed wheels (13, 19; 26, 28) set respectively on two horizontal shafts, the shaft of one of the two wheels of the stage level being comprised of the pivoting shaft (8) of the door, and the shaft of one of the two wheels of the last stage extending into the cavity (4) and bearing another toothed wheel (35) that meshes with teeth on a lower edge (5a) of the food-carrying tray (5). The invention relates for instance to microwave ovens.

Description

The present invention relates to a household oven comprising a housing having a vertical front face and containing a heating cavity open on the front face and intended to be closed by a door pivotally mounted about a horizontal axis located in the housing, said cavity being equipped with a tray supporting a food to be heated.

It relates more particularly to a household oven whose food carrier plate is movable in horizontal translation under the action of at least one movement transmission mechanism controlled by the door, disposed in the housing and adapted, on the one hand, to transform the pivoting movement of the door into a translational movement of the food carrier plate, and on the other hand, to ensure a displacement of the food carrier plate such that it comes to occupy either an engagement position in which it is completely contained in the cavity when the door is closed, that is to say a release position in which it projects transversely from the cavity when the door is open. An oven of this type is described in US-A-2,069,706.

This type of household oven is particularly advantageous insofar as it allows the food to be placed or removed while avoiding any risk of burns for the user. However, in such an oven, the transmission mechanism adapted to ensure the horizontal displacement of the food-carrying tray in response to the pivoting of the door generally consists of a complex set of rods hinged to each other, which makes it a mechanism complicated transmission.

The object of the invention is in particular to remedy this drawback by producing an oven such that the mechanism for transmitting movement between the door and the food-carrying tray is simple, economical and reliable.

According to the invention, the transmission mechanism comprises several successive stages of transmission associated with each other and each consisting of a toothed belt mounted to mesh on two rotary toothed wheels, respectively of the driving type and of the driven type, which are respectively wedged on two horizontal shafts parallel to each other, the shaft of the driving gear wheel of the first stage being constituted by the pivot axis of the door and the shaft of the driving gear wheel of the last stage having an end which opens transversely into the cavity and which carries a rotary toothed wheel known as a driving gear meshing with a toothing formed on a lower edge of the food-carrying tray and extending over the entire length thereof.

Preferably, there are two transmission stages, the second stage driving gear being wedged on the same shaft as the first stage driving gear.

• la figure 1 est une vue schématique en élévation partielle du four selon l'invention, la porte étant en position fermée (plateau porte-aliment dans la cavité) ;
• la figure 2 est une vue partielle en perspective éclatée d'un des deux mécanismes de transmission couplant la porte au plateau porte-aliment ; et
• les figures 3 et 4 sont des vues schématiques partielles de côté du four montrant, d'une part, la porte en position fermée et le plateau porte-aliment dans la cavité (figure 3), et d'autre part, la porte en position ouverte et le plateau porte-aliment en saillie de la cavité (figure 4).

Other characteristics and advantages of the invention will emerge from the description which follows, by way of nonlimiting example, with reference to the appended drawings in which:

• Figure 1 is a schematic partial elevational view of the oven according to the invention, the door being in the closed position (food carrier tray in the cavity);
• Figure 2 is a partial exploded perspective view of one of the two transmission mechanisms coupling the door to the food tray; and
• Figures 3 and 4 are partial schematic side views of the oven showing, on the one hand, the door in the closed position and the food carrier plate in the cavity (Figure 3), and on the other hand, the door in position open and the food tray protruding from the cavity (Figure 4).

The description of the invention which follows is made with reference to a microwave oven used in particular, but not exclusively, for defrosting and reheating a frozen food preparation, it being understood that the invention also applies to any type of electric oven, whether autonomous or integrated with a cooking appliance such as a stove.

The microwave oven illustrated in FIG. 1 comprises a housing 1, for example in the form of a straight parallelepiped, having a vertical front face 2, part of which is slightly recessed and has a front opening 3 leading to an internal heating cavity 4, for example of octagonal shape, in which is arranged transversely a rectangular plate 5 which supports a frozen food preparation P visible in FIGS. 3 and 4, and which is movable in horizontal translation under the action of the door as will be seen further.

In the cavity 4 opens at least one arrival of microwave radiation (not shown) connected to a microwave transmitter; optionally, at least one arrival of infrared rays (not shown) also opens into the cavity 4, which arrival being connected to an infrared transmitter.

The front opening 3 of the housing 1 is closed, during operation of the oven, by a door 6 (shown partially in broken lines in Figure 1) which is pivotally mounted about a horizontal axis 8 located in the lower part of the housing 1 and which is dimensioned so as to fit into the recessed part of the front face 2 so to reconstruct, with the latter, a perfectly flat facade.

The door 6 includes protective means (not shown) which, when the door is closed and the oven in operation, provide a seal against microwaves and, possibly, infrared.

The plate 5 carrying the food preparation is made of a material transparent to microwaves such as, for example, a ceramic coated with a glass-based enamel which is easy to maintain.

In the embodiment shown in Figure 1, the oven has two identical movement transmission mechanisms, each designated by the general reference 10, which are fully and laterally integrated in the housing 1, in the immediate vicinity of the front face 2 of this last, extending substantially vertically and symmetrically with respect to a median plane Q passing through the cavity 4, and which are each interposed between the axis 8 of the door 6 and one of the two lower edges 5a , 5b of the tray 5 carrying the food preparation.

Each of these two transmission mechanisms 10 is adapted, on the one hand, to transform the pivoting movement of the door 6 into a movement of horizontal translation of the plate 5 carrying the food preparation, and on the other hand, to ensure a displacement of said plate 5 such that it comes to occupy either an engagement position in which it is entirely contained in the cavity 4 when the door 6 is closed (see FIG. 3), that is to say a release position in which it projects transversely from the cavity 4 when the door 6 is opened, for example at 90 ° (see FIG. 4).

As the two transmission mechanisms 10 illustrated in FIG. 1 are identical, only one will be described hereinafter, for example the one on the right in FIG. 1, in order to simplify the description.

With reference to FIGS. 1 and 2, the transmission mechanism 10 according to the invention comprises several successive stages of transmission, in this case two stages, the first of which comprises a planed toothed belt 12 which is mounted in engagement with both a large lower toothed wheel 13, of the driving type, wedged on a horizontal shaft 14 which is mounted on the axis 8 of the door 6, at one end thereof, and which is engaged in a bore 16 formed in a plate vertical forming a bearing 17 integral with the housing, and on a small upper toothed wheel 19, of the driven type, wedged on one end of a horizontal shaft 20 parallel to the shaft 14 and engaged in a bore 21 formed in the plate 17. The second transmission stage also comprises a notched planar belt 23, considerably longer than the belt 12, which extends through an opening 24 formed in the plate 17 and which is mounted in engagement on both a large lower toothed wheel 26, of the driving type, wedged on the shaft 20 and placed on the same side as the toothed wheel 19 relative to the plate 17, and on a small upper toothed wheel 28, of the driven type, placed on the side opposite to the toothed wheel 26 relative to said plate 17 and wedged on a horizontal shaft 29, in the vicinity of one end thereof, which is engaged in a bore 31 formed in the plate 17. This shaft 29 opens out transversely at its other end 33 in the cavity 4, at a determined level thereof, and is enclosed in a cylindrical sealing sleeve 34 made of a microwave insulating material such as, for example, a ceramic. The through end 33 of the shaft 29 carries a large drive toothed wheel 35, of the driving type, cooperating by meshing with a toothing 36 forming a rack which is produced over the entire length of the lower edge 5a of the plate 5 carrying the food preparation.

Thanks to this transmission mechanism with toothed belts, not only a good sliding amplitude of the plate 5 is obtained, but also a flexible and silent operation.

The plate 17, Figure 2, has at its base two horizontal flat wings 38,39 which are fixed, for example by welding, on the bottom 41 of the housing 1 (Figure 1), and on its front edge, a vertical flat wing 42 which is fixedly applied, for example by welding, to the internal part of the front face 2 of the housing 1 (FIGS. 3 and 4).

As shown in FIG. 2, the toothed wheel 13 has a lateral flange 44 having a thin flat portion forming a heel 45, wedged angularly on the shaft 14 and adapted to come into abutment against the vertical wing 42 of the plate 17 at the end opening door 6, so as to keep door 6 in the open position according to the chosen opening angle, in this case 90 °. In this regard, the vertical wing 42 of the plate 17 advantageously constitutes an internal shielding of the front face 2 of the housing with respect to the abutment heel 45 when the door 6 pivots from its closed position to its open position.

In Figure 2, the control shaft 14 of the toothed wheel 13 has a flat 47 on which is mounted the side face 6a of the door 6 via a corresponding bore 48 formed therein. This flat 47 guarantees better pivoting of the door 6 and provides the latter with greater rigidity, which is necessary when the oven is used almost permanently, such as in the field of fast food.

It should be noted that the stroke of the plate 5 carrying the food preparation is determined as a function of the angular displacement of the door 6 and of the gear ratio between the driving gear wheels (13,26,35) and driven (19,28) of the transmission mechanism 10. By way of nonlimiting example, for an angular displacement of the door of 90 ° and a reduction ratio of the order of 4, the stroke of the plate carrying the food preparation is approximately 150 millimeters.

Preferably, the cavity 4 includes means for guiding the movable plate 5 carrying the food preparation. In the embodiment illustrated in FIGS. 3 and 4, these guide means consist of fixed pins 50 mounted transversely in the cavity 4 and arranged in staggered rows along the upper and lower edges of the plate 5.

The cavity 4 also includes coupling / uncoupling means (not shown) which, when the oven is not in operation, make it possible to make the plate 5 removable so as to facilitate its cleaning as well as that of the cavity.

FIG. 3 shows the plate 5 carrying the food preparation P in the engagement position in which it is entirely contained in the cavity 4 when the door 6 is closed.

After defrosting and reheating the food preparation P, the user opens the door 6, the pivot axis 8 of which rotates, counterclockwise, the toothed wheel 13 (FIG. 2), the rotational movement of which is transmitted to the toothed wheel 19 by means of the belt 12, as well as the toothed wheel 26 wedged on the same shaft 20 as the wheel 19. In turn, the toothed wheel 26 transmits its rotational movement to the toothed wheel 28 by means of the belt 23, as well as to the drive toothed wheel 35 wedged on the same shaft 29 as the wheel 28. By its rack and pinion gear with the plate 5 carrying the food preparation P, the toothed wheel 35 drives in horizontal translation the plate 5 which projects from the cavity 4 to occupy, at the end of the 90 ° opening of the door 6, its release position shown in FIG. 4. At the end of the opening of the door 6, the heel 45 of the flange 44 carried by the wheel toothed 13 abuts against the internal wing 42 applied against the front face 2 of the housing.

When the user closes the door 6, the plate 5 carrying the food preparation P moves from its release position (FIG. 4) to its engagement position (FIG. 3) under the action of the toothed wheels driven in a movement of reverse rotation from that described above.

Claims (10)

1. Domestic oven having a casing (1) with a vertical front face (2) and enclosing a heating cavity (4) open at its front face and designed to be closed off by a door (6) mounted so as to pivot about a horizontal shaft (8) situated in the casing, the said cavity (4) being equipped with a plate (5) which supports food to be heated and which is able to move in horizontal translation under the action of at least one movement transmission mechanism (10) controlled by the door (6), disposed in the casing (1) and able, on the one hand, to transform the pivoting movement of the door (6) into a translational movement of the food-carrying plate (5) such that the latter comes to occupy either an engaged position in which it is entirely contained within the cavity (4) when the door (6) is closed, or a disengaged position in which it projects transversely from the cavity (4) when the door (6) is open, characterised in that the transmission mechanism (10) includes several successive transmission stages associated with one another and each consisting of a notched belt (12; 23) mounted so as to mesh on two rotating toothed wheels (13, 19; 26, 28), of the driving and driven type respectively, which are keyed respectively on two horizontal shafts (8, 20; 20, 29), parallel to one another, the shaft of the driving toothed wheel (13) of the first stage consisting of the pivot shaft (8) of the door (6) and the shaft (29) of the driven toothed wheel (28) of the last stage having one end (33) which projects transversely into the cavity (4) and which carries a rotating toothed wheel referred to as the drive wheel (35) meshing with teeth (36) formed on a lower edge of the food-carrying plate (5) and extending over the entire length of the latter.
2. Domestic oven according to Claim 1, characterised in that the transmission stages are two in number, the driving toothed wheel (26) of the second stage being keyed on the same shaft (20) as the driven toothed wheel (19) of the first stage.
3. Domestic oven according to Claim 2, characterised in that the notched belt (23) of the second transmission stage is appreciably longer than that (12) of the first stage.
4. Domestic oven according to one of Claims 1 to 3, characterised in that the respective shafts (8, 20, 29) of the transmission stages are mounted in bores (16, 21, 31) formed in a single plate forming a bearing (17) integral with the casing.
5. Domestic oven according to Claim 4, characterised in that the plate forming a bearing (17) has a vertical flange (42) applied against the inner part of the front face (2) of the casing, and in that the driving toothed wheel (13) of the first transmission stage, keyed on the tilting shaft (8) of the door, has a member (44) with a heel (45), able to come to bear against the said flange (42) on the plate at the end of the opening of the door.
6. Domestic oven according to any one of the preceding claims, characterised in that the toothed wheels (13, 19, 26, 28, 35) of all the transmission stages have between them a transmission ratio that is determined so as to permit a relatively long travel in the food-carrying plate (5) when the door (6) pivots either from its closed position to its open position, or from its open position to its closed position.
7. Domestic oven according to any one of the preceding claims, characterised in that guide means (5) are disposed in the cavity (4) in order to guide the food-carrying plate (5) during its movement.
8. Domestic oven according to any one of the preceding claims, in which the cavity (4) is subjected to microwave radiation, characterised in that the part of the shaft (29) of the driven toothed wheel (28) of the final transmission stage, situated between this driven toothed wheel (28) and the toothed driving wheel (35) positioned in the cavity, is sheathed in a sleeve (34) that is impervious to microwaves.
9. Domestic oven according to Claim 8, characterised in that the food-carrying plate (5) is produced from a material that is transparent to microwaves.
10. Domestic oven according to Claim 9, characterised in that the material transparent to microwaves is a ceramic coated with a glass-based enamel.

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