EP0496244B1 - Device to put a micro-wave oven in a starting stand by portion - Google Patents

Abstract

The oven includes a cooking enclosure fitted with a movable door (3) hinged to the front face (2) of the said oven and equipped with a fastener (4) comprising a nose (5) and a notch (6). The fastener penetrates into an opening (9) in the front face in order to actuate a movable interlocking element (7). According to the invention, the interlocking element includes a pivoting wheel (20) positioned on a platen (14) fixed to the inner front face of the oven. The said wheel includes a first face (A) comprising two stop contacts (22 and 23), a safety interlock consisting of a locking finger (25) fixed to the second face (B) of the wheel and controlled by a safety pin (24) protruding through a slot (23') transversely to the first face (A) and intended, either to abut with the catch lock (26) of the platen, or to permit rotation of the wheel. Application to all closing devices. <IMAGE>

Description

The present invention relates to microwave ovens and more particularly the safety devices used in microwave ovens. Generally, a microwave oven has a cooking cavity equipped with a movable door hinged on the front face of said oven and intended to completely close the orifice of the cavity by folding down on the front face. Said movable door is kept closed at least by a hook which penetrates into an opening situated on said front face and which comprises an actuating nose of a locking element as well as a notch situated behind the nose and in which the element lock engages. Said locking element thus positioned authorizes the subsequent closing of a switch for operating said oven under the action of an operating button located on a dashboard arranged on the front face of the oven. Such a device is described for example in GB-A-2 176 658.

The openings through which the hook enters being sufficiently visible when the door of the microwave oven is open, it is possible for a child to introduce into this opening a flat element, for example, the handle of a spoon, to activate the locking element.

In this position, the oven only waits for the press of an operating button to start. This security system is therefore not sufficiently reliable and can be dangerous for children.

The object of the invention is to remedy this drawback by implementing a device making it possible to avoid any operation when the door of the microwave oven is open.

According to the invention the device is characterized in that the locking element consists of a wheel which is positioned on a plate fixed transversely to the internal front face of the microwave oven and which is fixed to said plate by a shaft parallel to said front face and around which the wheel can perform a rotational movement, said wheel comprising a first face comprising two stop pads, a first stop pad located in the path of the nose and a second angularly offset stop pad and intended after rotation of said wheel by action of the nose on the first stud, to come to engage in the notch of the hook as well as a safety lock comprising a blocking finger which is intended to come into abutment on a stop boss integral with the plate and arranged opposite the second face of the wheel, and which is mounted movable for this purpose against an elastic means on said second face of the wheel, said finger locking being controlled by a safety lug which protrudes through a light transverse to the first face of the wheel, and which is arranged between the two stop studs so as to occupy two positions, that is to say a standby position for starting for which it is actuated by the nose of the hook and in which it retracts the locking finger thus allowing a determined rotation of the wheel so as to allow the subsequent closing of the operating switch, ie an active position for which, in l absence of an action of the nose, it comes up against the boss stopping and hindering the rotation of said wheel thus preventing authorization to close the switch.

Thanks to this device according to the invention, a simple system to be used is used and the safety of a microwave oven is considerably increased by preventing any user from triggering the operation of the appliance when the door of said oven is opened. On the other hand, the device mounted parallel to the openings through which the locking hook enters, makes it possible to free up a large space behind the dashboard of the microwave oven and thus to limit the bulk.

• la Figure 1 représente en perspective le dispositif de mise en position de démarrage selon l'invention et agencé dans un four à micro-ondes représenté partiellement et équipée d'une porte mobile en position entrouverte ;
• la Figure 2 représente à plus grande échelle et en perspective le dispositif de mise en position d'attente de la Figure 1 ;
• Les Figures 3a et 3b représentent en vue éclatée l'élément de verrouillage de la Figure 2 illustré dans deux étapes différentes de fonctionnement du dispositif selon l'invention ;
• la Figure 3c représente en vue éclatée l'élément de verrouillage selon l'invention avant son montage sur une platine fixée transversalement à la face avant du four à micro-ondes ;

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended drawings in which:

• Figure 1 shows in perspective the device for setting the start position according to the invention and arranged in a microwave oven partially shown and equipped with a movable door in the ajar position;
• Figure 2 shows on a larger scale and in perspective the waiting position setting device of Figure 1;
• Figures 3a and 3b show in exploded view the locking element of Figure 2 illustrated in two different stages of operation of the device according to the invention;
• Figure 3c shows an exploded view of the locking element according to the invention before it is mounted on a plate fixed transversely to the front face of the microwave oven;

According to Figure 1, only part of the elements constituting a microwave oven is shown. The microwave oven comprises a cooking cavity, not shown, the side walls of which bear the reference 1. A front face 2 of the microwave oven forms an opening giving access to the cooking cavity. A movable door 3 articulated on the front face 2 is intended to completely close the cooking cavity. Said movable door 3 comprises a closing system, for example, at least one hook 4 fixed, for example, by removable fixing on the door and making it possible to obtain complete closure of the door; this hook 4 comprises, for example, an actuating nose 5 and a notch 6. The notch 6 has, for example, an inverted U shape, the curved part of the U being slightly modified so as to create a slight slope s' elevating towards the nose and facilitating the sliding of the locking element 7 of the microwave oven. The actuating nose has, for example, a thickness e like the entire hook 4, a width 1 and a narrowing 8 sufficiently wide to avoid any flexibility of said nose when the nose comes into contact with the locking element 8 of the microwave.

The front face 2 of the microwave oven comprises, in addition to a first opening 9 allowing the hook 4 of the movable door 3 to penetrate in order to come to engage in the locking element 7, other openings of which only one 10 is shown in Figure 1, said openings allowing, for example, by fixing lugs 11, 12 and 13, the positioning of a plate 14 supporting, in addition, the locking element and a switch 15 for operating the microwave oven, said plate 14 is fixed transversely to the front face 2 of the microwave oven between one of the side walls 1 of the cooking cavity of the microwave oven and locations 16, 17, 18 and 19 provided for mounting a dashboard (not shown) containing, for example, components determining time, power, rapid cooking instructions with timer setting and switching on the appliance.

The locking element 7 fixed on the plate 14 consists, for example, of a wheel 20. The wheel 20 is rotatably mounted on said plate 14 around a shaft 21 positioned parallel to the front face 2 of the micro oven -waves and integral with the plate 14. Said wheel 20 further comprises two faces A and B placed opposite, of which only one A is visible in FIG. 1. The first face A comprises, for example, two studs stop 22 and 23, a first stop stud 22 located on the path of the nose 5 of the hook 4 of the movable door 3 and a second stud 23, located near the edge 22 ′ of the first face A and angularly offset relative to the first pad 22 to avoid any abutment of the nose 5 on the second pad 23 when the movable door 3 is closed, as well as a light 23 ′ arranged angularly between and under the two stop pads 22 and 23 and allowing a lug to safety 24 positioned transversely to the first face A of the wheel 2 0 and constituting, in addition, an element of a locking finger 25 (shown in Figures 3a to 3c) and mounted movably on the second face B of the wheel 20 and facing the plate 14. The locking finger 25 is an element of a safety lock comprising, in addition, a stop boss 26 integral with the plate 14 and disposed opposite the second face B of the wheel 20. The locking pin 25 is mounted movable to the against an elastic means consisting, for example, of a spring system 27 (shown in Figures 3a to 3c), fixed on the second face B of the wheel 20 and which tends to bring the free end 28 of the finger 25 at the periphery of the wheel 20 near the boss 26 so that, when no action is exerted on the safety lug 24, the rotation of the wheel 20 is limited to the distance existing between the free end 28 of the locking finger 25 and the boss 26. Said studs 22 and 23 are, for example, ovoid. The first face A of the wheel 20 also includes a shaft 29 positioned on the periphery of the wheel 20 and located at the top of a triangle passing through the abutment pads 22 and 23. A rocker 30 is mounted free around this tree 29 of pendulum. The free end 31 of this rocker 30 has, for example, a rounded shape.

According to Figure 2, when the oven door is closed, the second stud 23 and the safety lug 24 of the wheel 20 are placed inside the notch 6 of the hook 4. The wheel 20 having on its first face At the shaft 29 on which the rocker 27 is movably mounted, said rocker 27 passes from the position shown in Figure 1 to the position shown in Figure 2. Indeed, during the rotation of the wheel 20, the shaft 26, on which the rocker 27 is pendulumly mounted, performs a rotational movement limited by a shoulder 32 of the hook 4 (represented by dotted lines). The shoulder 32 is intended to abut against the front face 2 of the oven when the movable door 3 comes to completely close the cavity, a distance d between said shoulder 32 and the internal face of the notch 6 adjacent to the nose 5 being thus defined by rigorously by the manufacturer to obtain complete closure of the door 3 without play.

This rocker 30, by gravity effect, has its end 31 which is positioned at the level of the switch 15. This switch 15 having a push button 33 for triggering, it suffices with a pivoting movement of the rocker 30 to activate the 'switch 15 for operating the microwave oven. This pivoting movement of the rocker 30 is caused, for example, by a flap 34 mounted mobile in rotation about a hinge pin 35. The rotation of this flap, along an arrow F4 , is caused, for example, by a operating button 36 which is the start button for the microwave oven located on the dashboard and shown partially.

According to FIG. 3a, when the movable door 3 is closed on which the hook 4 is fixed, the nose 5 of said hook 4 performs a rotational movement around the hinge axis of the door according to an arrow F1 . The nose 5 engages in the opening 9 of the front face 2 of the microwave oven and strikes the first stud 22 of the wheel 20. Before the nose 5 contacts the first stud 22, the locking finger 25, shown detached from the wheel 20 for a better understanding, is located near the boss 26 to abut against the latter if no action is exerted on the safety lug 24. The closing of the door continuing, as shown on Figure 3a, the force F1 exerted on the first pad 22 drives the wheel 20 in rotation.

On the other hand, according to Figure 3b, the nose 5 of the hook exerts through its lower part, on the safety lug 24, an action in the direction of arrow F2 . The locking finger 25 is mounted movably on an axis 37 of the second face B of the wheel 20, against the spring 27 comprising two ends 38 and 39, one 38 is linked to the locking finger 25, the another 39 is linked to the wheel 20, this connection being represented figuratively in the exploded views 3a, 3b, 3c.

The tilting of the safety pin 24 and the rotation of the wheel 20 allow the locking finger 25 to pivot and retract, thus avoiding the boss 26 which limited the angular displacement of the wheel 20 when no action is exerted on the safety lug 24.

The final position of the wheel 20 after complete closure of the movable door 3 of the microwave oven is shown in FIG. 2.

According to Figure 3c, the finger 25 has a hole 40, parallel to the safety pin 24 and which allows the threading on the shaft 37 of the second face B of the wheel 20. The wheel 20 has its fixing shaft 21 rotatably mounted in a hole 42 made in the plate 14. A retaining washer (not shown) fixed on the end of the shaft 21 after its engagement in the hole 42 on the other face (not shown) of the plate 14 allows the axial maintenance of the wheel 20 on the plate 14 leaving a free rotation of said wheel 20 around the shaft 21.

Said wheel 20 is limited in its angular displacement, by the hook 4 of the movable door 3 of the microwave oven. In addition, to pull the hook 4 towards the interior of the oven, and therefore apply the door against the front face, the wheel 20 and therefore the first stud 22 are subjected to a rotary drive device comprising a tenon 43 mounted on the second face B of the wheel 20 and placed in alignment with the shaft 29 of the first face A of the wheel 20, said lug 43 passing through a slide 44 produced on the plate 14.

To control said movement of the stud 43, the end 45 of the stud 43 protruding, after mounting of the wheel 20 of the plate 14, is fixed to a first end 46 of a toggle joint 47 with an unstable midpoint under the effect a spring 48 and shown in dotted lines because located on the other face of the plate 14, while a second end 49 passes through a support 50 fixed and integral with the plate 14 and serves as a stop for the spring 48 as well as a bearing slide for the knee lifter 47.

Thus the stud 43 of the wheel 20 passes from a first position illustrated at 51 representing the axis of the stud 43 when no action is exerted on the studs 22 and 23 as well as on the safety lug. 24, in a second position illustrated at 52 representing the axis of the post 43 after an action on the aforementioned elements. An arrow 53 shown in the slide 44 describes the rotational movement made by the lug 43 of the wheel 20 when the locking pin 25 of the wheel 20 is retracted, thus avoiding the abutment against the boss 26 and allowing the continuation of the rotational movement of the wheel 20.

Other operating keys can trigger the rotation of the rocker 30 to trigger the switch 15 for operating said oven, for example, a preprogrammed timing device of a microwave oven of the type described, for example, in patent application No. 2,630,613 or an electronic button of a microwave oven, but in these latter cases it is essential to adapt and position adequate mechanisms not shown to operate the device. The device according to the invention is applicable to microwave ovens but can be applied to other devices requiring very reliable security.

Claims (9)

1. Device for putting on stand-by a microwave oven having a cooking chamber equipped with a movable door (3) hinged on the front face (2), of the said oven and designed to close off the opening of the chamber completely by closing against the front face (2) the said movable door (3) being held closed by means of a hook (4) which enters an opening (9) situated on the said front face (2) and which has a nose (5) for actuating a movable locking element (7) and a notch (6), situated behind the nose (5), in which the locking element (7) engages and allows the subsequent closure of a switch (15) for starting up the said oven under the action of an operating button (36) situated on a control panel arranged on the front face of the oven, characterised in that the locking element (7) consists of a wheel (20) which is positioned on a plate (14) fixed transversely to the inner front face (2) of the microwave oven and which is fixed to the said plate (14) by a shaft (21) parallel to the said front face (2) and about which the wheel (20) may effect a rotation movement, the said wheel (20) having a first face (A) comprising two stop studs (22, 23), a first stop stud (22) situated on the path of the nose (5) and a second stop stud (23) offset angularly and intended, after the rotation of the said wheel (20) by the action of the nose (5) on the first stud (22), to engage in the notch (6) in the hook (4), and a safety lock comprising a locking finger (25) which is designed to come into abutment on a stop projection (26) fixed to the plate (14) and disposed opposite the second face B of the wheel, and which is mounted so as to be able to move for this purpose against an elastic means (27) on the said second face (B) of the wheel, the said locking finger (25) being controlled by a safety snug (24) which projects through a slot (23′) transversely to the first face (A) of the wheel (20), and which is arranged angularly between and below the two stop studs (22, 23) so as to occupy two positions, either a stand-by position in which it is actuated by the nose (5) of the hook (4) and in which it retracts the locking finger (25) thus allowing a given rotation of the wheel (20) so as to allow the subsequent closure of the operating switch (15), or an active position in which, in the absence of any action by the nose (5), it comes into abutment against the stop projection (26) and impedes the rotation of the said wheel (20), thus preventing the closure of the switch (15) from being allowed.
2. Device for putting a microwave oven on stand-by, according to Claim 1, characterised in that the first face (A) of the wheel (20) has a shaft (29) on which a rocker (30) is mounted movably, the said rocker, after rotation of the wheel (20) under the action of the hook (4) on the movable door (3), moving from a first idle position corresponding to the door (3) being open, to a second position in which the microwave oven is on stand-by, corresponding to the complete closure of the door (3) and in which it allows the subsequent closure of the switch (15).
3. Device for putting a microwave oven on stand-by, according to Claim 2, characterised in that the rocker (30) is mounted so as to swing about the shaft (29) and is positioned, by gravity, in the said second position, in proximity to a pushbutton (33) on the operating switch (15) so as to be able to close the operating switch when the said rocker (30) is brought by pivoting into contact with the push-button (33).
4. Device for putting a microwave oven on stand-by, according to Claim 3, characterised in that the pivoting of the rocker (30) is controlled by a flap (34) mounted so as to rotate freely about a pin (35) fixed to the plate (14) and actuated by the operating button (36) positioned on the control panel of the microwave oven.
5. Device for putting a microwave oven on stand-by, according to Claim 4, characterised in that the operating button (36) for the microwave oven is the button for starting up the said microwave oven.
6. Device for putting a microwave oven on stand-by, according to Claim 1, characterised in that the second face (B) of the wheel (20) has a peg (43) fitting into a channel (44) formed in the plate (14) in order to limit angularly the rotation movement of the wheel (20).
7. Device for putting a microwave oven on stand-by, according to Claim 6, characterised in that the peg (43) on the wheel (20) has an end (45) which fits into a first end (46) of a toggle lever (47) with a mid-point which is unstable under the effect of a spring (48) so as to obtain an abrupt rotation movement of the wheel (20).
8. Device for putting a microwave oven on stand-by, according to Claim 1, characterised in that the notch (6) in the hook (4) is in the shape of an inverted U, the central curved part of which has a slight slope rising in the direction of the nose (5).
9. Device for putting a microwave oven on stand-by, according to any one of the preceding claims, characterised in that the hook has, at its base, a shoulder (32) designed to come into abutment against the front face (2) of the oven when the movable door (3) closes off the chamber completely, the distance (d) between the said shoulder (32) and the internal face of the notch (6) adjacent to the nose (5) being thus defined stringently in order to obtain complete closure of the door (3) without any play.

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