APPLIANCE PROVIDED THEREWITH

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates to a resettable door locking device for an electric household appliance, in particular a dishwasher, and electric household appliance provided therewith. In particular, the invention relates to a door locking device that can be used even when one of its latching devices, for any reason, is incorrectly placed in the locking position already with the electric household appliance door still open.

Discussion of Related Art

EP 1344486 is known for a door locking device of high simplicity and reduced size based on a rotating latching device combined with a bistable elastic mechanism which makes the latching device selectively assume two different stable positions, consisting respectively of a locking position, wherein the latching device engages, with the door closed, a hooking element, usually constituted by a U-shaped bracket, and in an unlocking position, wherein the latching device does not engage the hooking element.

It is also known, from DE102007033451, a door locking device for a dishwasher wherein the hooking element, carried by the electric household appliance casing, is to be coupled with a revolving latching device carried by a support body, in turn in use, which can be positioned on the door of the electric household appliance.

However, many known devices, even when they are completely satisfactory, are generally bulky and those of a less modern conception are designed to be mounted with their bulkier part in the thickness of the electric household appliance door; this prevents the construction of electric household appliances with increased load capacity, which would be extremely useful, particularly in the dishwasher field, and the creation of thin doors.

In addition, in known door-locking devices, if the rotating latching device is accidentally positioned in the locking position when the electric household appliance door is still open, on the one hand it is impossible to lock the door correctly and, on the other hand, the microswitch signal of the locked door, which cooperates directly with the rotating latching device or with an element associated with it, mistakenly provides a locked door signal to the electric household appliance, which can therefore be started with the consequent risk of fluid leakage to the outside. Even if the user then detects the incorrect positioning of the rotating latching device, he/she should fit/reset it manually, making it rotate to the unlocked position. In order to do this, dedicated tools are indispensable, without which there is a risk for the user to get hands or fingers injured, albeit slightly.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a door locking device for an electrical household appliance, in particular a dishwasher, which is constructively simple, of reduced cost and dimensions, and of high reliability which allows to overcome the drawbacks of the prior art, in particular that allows to report any abnormal positioning of the latching device and to fit/reset the device automatically, without a manual intervention by the user.

Therefore, this invention relates to a resettable door locking device for an electrical household appliance, in particular a dishwasher, and to an electrical household appliance equipped with such a device, as defined in the annexed claims.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

Further characteristics and advantages of this invention will become clear from the description which is given below of a preferred embodiment, illustrated purely by way of non-limiting example and with reference to the attached drawings, wherein:

Fig. 1 illustrates schematically a three-quarter rear perspective view of a door locking device according to the invention applied on an electric household appliance, known and shown in broken lines only partly and only schematically for simplicity;

Fig. 2 illustrates schematically a three-quarter perspective view taken sideways and sectioned according to a plane II-II of the door locking device of Fig. 1 represented in a first operating position;

Fig. 3 illustrates schematically the same perspective and sectioned view of Fig. 2, with the door locking device of the invention represented in a second operating position;

Figs. 4 and 5 illustrate schematically the same perspective and sectioned view of Fig. 2, with the door locking device of the invention represented, respectively, in a third and fourth operating position;

Figs. 6, 7 and 8 illustrate schematically the same perspective and sectioned view of Fig. 2, with the door locking device of the invention represented in a sequence of operating positions that show its automatic fit/reset sequence;

Fig. 9, illustrates a sectioned and exploded perspective view of the door locking device of the invention; and Fig. 10 illustrates an elevated and sectioned side view of the device of Fig. 1 in a configuration immediately preceding that illustrated in Fig. 6.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Figs. 1 to 5 and Figs. 9 and 10, 1 indicates as a whole a door locking device for an electric household appliance 2, in particular a dishwasher, of which the electric household appliance is illustrated for simplicity only part of a structural element 3, in this particular instance, a front upper crosspiece of a casing of the electric household appliance delimiting an upper edge of an access compartment to a washing chamber or tub 4 closed in use by a closing door 5.

Although the following non-limiting description refers to the case of a dishwasher with front door, it remains clear that the door locking device 1 according to the invention can be applied both to doors with horizontal rotation axis and to doors with vertical rotation axis. Therefore, the invention can also be used on drawer dishwasher machines.

The door locking device 1 comprises a support body 6 configured to be fixed in a known way to the door 5 of the electric household appliance 2, a bracket 7, for example 11- shaped or frame-shaped, and configured to be fixed in a known way to the structural element 3 and a latching device 8 carried by the support body 6 and configured to cooperate in use with the bracket 7, in the manner that will be illustrated later.

The latching device 8 in turn comprises a locking tooth 10 carried by the support body 6 and constrained to the support body 6 so as to be able to rotate relatively thereto around a first A axis (Figs. 2 and 9) and, at the same time, according to an aspect of the invention, so that the first A axis can, as will be illustrated later, translate relatively to the support body 6.

The locking tooth 10 comprises a first hook-shaped end 12, configured to couple with a transversal element 11 of the bracket 7 to lock in use, in a known way, the door 5 against the structural element 3 of the electric household appliance 1.

The latching device 8 further comprises a stem 13 carried by the support body 6 sliding along a symmetry B axis (Fig. 9) of the stem 13 itself and cooperating with a second end 14 of the locking tooth 10, opposite the end 12.

Furthermore, the end 14 is delimited by a first cam profile 15 which cooperates in contact with a second cam profile 16 obtained on a head 17 of the stem 13 facing the locking tooth 10.

In combination with the foregoing, the latching device 8 also includes, in addition to the stem 13 and the respective cam profiles 15, 16, a compression spring 18, in the non-limiting example illustrated a helical spring, operatively associated with the stem 13 and configured to thrust cam profiles 15 and 16 into contact with each other.

Here and below, by "compression spring" is intended an elastically deformable spring configured/mounted so as to be subjected, both at rest and during its operation, to only compression stresses.

According to an aspect of the invention, the latching device 8 finally comprises a frame-shaped tilting element 19, in the illustrated example configured as a substantially quadrangular frame, and hinged to the support body 6 so as to be able to rotate relatively thereto around a second C axis parallel to the first A axis; in addition, the tilting element 19 is configured to cooperate with the transversal element 11 of the bracket 7 regardless of the locking tooth 10.

In fact, the tilting element 19 is mounted externally on the support body 6 to which it is hinged around the C axis in a distal and independent position of the A axis and has opposite ends 20, 21 (Fig. 9) defined by crosspieces of the tilting frame element 19 which are parallel to the transversal element 11 of the bracket 7 and are arranged, respectively, the end 20 on the part of the end 12 of the tooth 10, adjacent thereto, and the end 21 on the part of the stem 13, adjacent to a seat 22 (Fig. 1) for a known microswitch 23 carried externally jointly and severally by the support body 6, preferably obtained integrally as a piece therewith.

According to an aspect of the invention, the cam profiles 15, 16 are configured to form, together with the locking tooth 10, the support body 6, to the stem 13 and to the compression spring 18, a bistable mechanism 24 (Fig. 2) adapted to selectively causing the locking tooth 10 to assume a receiving position, shown in Figs. 2 and 3, and a locking position, shown in Fig. 5.

In the receiving position, a recess 25 obtained in the first end 12 of the locking tooth 10 is directed in parallel to respective longitudinal side members 26 of the bracket 7, perpendicular to the transversal element 11 of the bracket 7, to receive the transversal element 7 inside it.

Furthermore, the support body 6 has a reception slit 27 (Fig. 9) for the bracket 7, arranged facing the locking tooth 10 and configured to be crossed through, in use, by the bracket 7 on the side of the transversal element 11 thereof to reach the locking tooth 10.

In the receiving position, the tooth 10 has the recess 25 facing towards, and faces, the slit 27; the end 20 or crosspiece of the frame-shaped tilting element 19 also faces, and faces the, slit 27. The end 20 also has a central portion 29 shaped like a C (Fig. 9) which, in the receiving position of the tooth 10, is arranged astride the end 12 of the tooth 10 and flanks the recess 25 on opposite sides, facing the transversal element 1 1 of the bracket 7 together with the recess 25 thereof. The conformation of the tilting element 19 is in any case such as to avoid any interference and/or cooperation with the locking tooth 10.

In the locking position, instead, the recess 25 is directed transversely to the side members 26 of the bracket 7 and is arranged substantially perpendicular, or at least transversely, to the slit 27 (Fig. 5).

Preferably, the head 17 of the stem 13 is hinged to an arm 30, for example shaped like a fork (Fig. 9), which in the illustrated non-limiting example protrudes overhanging from the second end 14 of the locking tooth 10, perpendicular to the A axis, and which is obtained integrally in one piece with the end 14, so that the head 17 of the stem 13 rotates in use relatively to the arm 30 around a third D axis (Fig. 9), parallel to the first A axis. Obviously, the arm 30 could be missing or be integrated into the end 14 which in this case would preferably be fork-shaped. Other possible configurations, obvious to the person skilled in the art, are anyhow possible.

In the non-limiting but illustrated preferred example, the support body 6 comprises a hollow boxed portion 31 (Fig. 9) housing internally the stem 13, the compression spring 18 and the locking tooth 10, with the exception of the end 12 of the latter, which protrudes overhanging from the support body 6 through a slit 32 (Figs. 1 and 9) of the boxed portion 31.

The first A axis is defined by a pair of profiled elements 33 (Figs. 9 and 10) which protrude overhanging transversely from opposite sides of the locking tooth 10 and which are arranged between the ends 12 and 14 thereof.

The laterally protruded overhanging profiled elements 33 cooperate in contact with a radially internal perimeter edge 34 (Fig. 9) of the boxed portion 31 of the support body 6 and the compression spring 18 is configured to keep the laterally protruded overhanging profiled elements 33 of the locking tooth 10 permanently in contact with the radially internal perimeter edge 34 of the boxed portion 31 of the support body 6, so that the first A axis defined by the profiled elements 33 can translate relatively to the support body 6 along the profile of the perimeter edge 34.

In particular, the radially internal perimeter edge 34 of the boxed portion 31 of the support body 6 forms a loop 35 (Figs. 6 and 7) configured to receive the laterally overhanging profiled elements 33 of the locking tooth 10 and within which the profiled elements 33 are normally kept by the compression spring 18, which is pre-loaded, so as to be free to rotate relatively to the support body 6 within the loop 35 between the aforementioned receiving and locking positions.

The lateral protruding overhanging profiled elements 33 of the locking tooth 10, instead of being simple pins, are also preferably shaped as rounded wedges or, anyhow, configured to cooperate selectively with respective portions of the radially internal perimeter edge 34 of the boxed portion 31 immediately adjacent, from opposite sides, to the loop 35, to act as end stops to determine the angular position of the receiving and locking positions of the locking tooth 10 with respect to the support body 6.

The stem 13 is engaged axially passing through a shoulder ring 36 (Figs. 2 and 9) hinged to the support body 6 so that the shoulder ring 36 rotates relatively to the support body 6 around a fourth E axis (Fig. 9) parallel to the first A axis and preferably arranged coaxial to the second C axis. The compression spring 18 is inserted in a pack, pre-compressed, between the head 17 of the stem 13 and the shoulder ring 36, so that it constantly thrusts the head 17 against the end 14 of the tooth 10.

The recess 25 is configured to retain within it the transversal element 1 1 of the bracket 7 when the locking tooth 10 is in the locking position and when the recess 25 thereof has previously been engaged by the transversal element 1 1 of the bracket 7 with the locking tooth 10 in the receiving position (i.e. when the tooth 10 was previously in the receiving position).

According to a further aspect of the invention, the locking tooth 10 is delimited, between the recess 25 and the second end 14 thereof, by a plane surface 37, obtained in a position immediately adjacent to the cam profile 15 and on the part of the recess 25. The plane surface 37 faces towards, or on the side of, the slit 27 of the support body 6 and, in the locking position, defines an inclined plane facing the slit 27 and configured to cooperate with the transversal element 11 of the bracket 7 if the recess 25, with the locking tooth in the locking position, had not already been engaged by the bracket 7 (Figs. 6 and 10).

This inclined plane defined by the surface 37 is configured to determine, as a consequence of a thrust exerted thereon by the transversal element 11 of the bracket 7, an axial thrust on the compression spring 18, through the stem 13, which thrusts the first A axis to move away from the slit 27 to allow the transversal element 11 of the bracket 7 to "jump" the locking tooth 10 and snap-fit with the recess 25 thereof (Fig. 7).

The operation of the described door locking device 1 is as follows.

With the door 5 open, the device 1 is in the configuration of Figs. 1 and 2, wherein the tooth 10 is in the receiving position, which is one of the two stable positions allowed by the bistable mechanism 24. This position is stable, since the elastic thrust exerted by the spring 18 is discharged to the left (in the Figures) of the A axis, retaining the profiled elements 33 pressure supported inside/against the loop 35 (Fig. 2).

When the door 5 closes, the bracket 7 receives the slit 27, the transversal element 1 1 is supported against the end 12 of the tooth 10, up to inside the recess 25 (Figs. 3 and 4). The thrust of the bracket 7 is eccentric with respect to the A axis and therefore forces the tooth 10 to rotate around the A axis, on the hinge defined by the loop 35 and the profiled elements 33; consequently also the end 14 rotates and the cam profiles 15, 16 rotate on the E axis the stem 13 and the shoulder ring 36, further compressing the spring 18 (Figs. 4 and 5) until the B axis exceeds the alignment position of the A axis, defined by the loop 35, and the E axis, and moves to the right thereof in the Figures, triggering the mechanism 24 in a new stable position, bringing the tooth 10 into the locking position (Fig. 5).

In this position the recess 25 is rotated by about 90°, and therefore engages the transversal element 11 so that it can no longer be extracted through the slit 27. The elastic preload of the spring 18 also keeps the door 5 compressed in the closed position.

During the described movement, the tilting element 19 is also rotated by the thrust of the transversal element 11 on the C axis, bringing the end 21 against the microswitch 23, which is activated, signaling the status of closed and locked door.

In the opening phase, an opposite movement takes place; starting from the configuration in Fig. 5. The user, in this case, to open the door 5 must exert a pull on the door handle. The transversal element 1 1 which engages the recess 25 urges the end 12 to rotate towards the slit 27; the tooth 10 rotates on the A axis producing the compression of the spring 18 and the bistable mechanism 24 snaps towards the position of Fig. 3, passing through a configuration wherein, during the opening phase, the crosspiece 1 1 of the bracket 7 is placed next to the tooth adjacent to the inclined plane 37, while the profiled elements 33 remain engaged in the loop 35, due to the thrust of the spring 18, so that the A axis does not translate but the tooth 10 rotates around the A axis, which remains stationary. Once the position of Fig. 3 is reached, the bracket 7 can be extracted from the slit 27 and return to the starting position of Figs. 1 and 2, with the door 5 open.

During these opening movements, the microswitch 23 is disconnected since the tilting element 19 is rotated in the inverted direction either by the thrust of the microswitch 23 thereof (which is internally equipped with a spring) or by a specially provided spring (not shown) for example on the C axis, following the backward movement of the transversal element 11 with the end 20 thereof. With specific reference to Figs. 6 to 8 and 10, the tooth 10 could accidentally find itself already in the locking position, while the door 5 is open (Fig. 10). In this case, the door locking device 1 is able to reset itself automatically without manual intervention by the user.

Firstly, the user is informed of the anomaly in the event that the door 5 is half- closed, but not locked, since even if the tooth 10 is in the locking position, the absence of the bracket 7 within the slit 27 does not cause the rotation of the tilting element 19 and therefore does not activate the microswitch 23.

Secondly, by thrusting the door 5 towards the closed position, the user thrusts the bracket 7 into the slit 27. The tooth 10 is in the locking position. This implies that the inclined plane defined by the plane surface 37 faces the slit 27 and therefore intercepts the transversal element 1 1 of the bracket 7, which begins to slide along the inclined plane 37 while the door 5 progressively approaches the closed position.

This movement involves an axial thrust against the stem 13 which compresses the spring 18, but the B axis remains to the left of the rotation A axis of the tooth 10.

Therefore, the tooth 10 is pushed to move away from the slit 27 descending into the boxed portion 31 through the slit 32, following a straight section 38 (Fig. 9) of the edge 34 against which the elements 33 are thrusted by the spring 18.

Consequently, the tooth 10 assumes sequentially the positions of Figs. 6, 7 and 8, thanks to which the element 1 1 jumps the tooth 10 which is thrusted downwards and goes to engage the recess 25. As soon as this occurs, the thrust on the inclined plane 37 ceases and under the thrust of the spring 18 the tooth 10 rises again (Fig. 8) until it assumes the correct position of Fig. 5.

To mount the latching device 8 within the boxed portion 31 it is possible to obtain the support body 6 by means of a single block. Thanks to the elasticity of the thermoplastic material and the entrance 39, it is possible to snap-fit the shoulder ring 36 and the different components of the latching device 8 described within the boxed portion 31 , in containment holes 28(6).

Through the containment holes 28, the shoulder ring 36 rotates relatively to the support body around a fourth E axis, passing through the center of the containment holes 28.

Finally, from what has been described it is clear that the invention also relates to an electric household appliance 2, in particular a dishwasher, comprising a structural element 3 delimiting an access compartment a washing chamber or tub 4 and a door 5 operatively associated with the access compartment and configured to assume an open position, wherein it allows access to the washing chamber or tub 4, and a closed position wherein it is locked against the structural element 3.

The electric household appliance 2 comprises a door locking device 1 as described having the support body 6 fixed jointly and severally to the door 5 in a known way, for example by means of screws not illustrated for simplicity, and the bracket 7 fixed jointly and severally to the structural element 3, also in a known way and not illustrated for simplicity.

The support body 6 has a lateral seat 22 housing a microswitch 23 and the frameshaped tilting element 19 is configured to cooperate with the microswitch 23 only when the transversal element 11 of the bracket 7 engages the recess 25 of the locking tooth 10, thus warning the user in case of anomalies or in any case preventing the electric household appliance

2 from starting if the door 5 is not locked.

All the purposes of the invention are therefore achieved.