in particular an oven"

DESCRIPTION

Field of the invention

The present invention relates to a door-locking device for an electrical household appliance, in particular an oven, having the characteristics referred to in the preamble of Claim 1. Devices of this type are known, for example, from EP 1640493 A2 and EP 1703212 A2, filed in the name of the present Applicant.

Prior art

As explained in the introductory part of the aforesaid prior documents, devices of the type referred to usually comprise a main body, associated to which are a movable locking member and a corresponding actuation system, which can be electrically controlled for displacing the locking member between an operative condition or condition of engagement and an inoperative condition or condition of release, with respect to a suitable retention element. The main body of the door- locking device is usually fixed to the stationary structure of the appliance, with its locking member that is able to co-operate with the retention element, which is defined or mounted on the door of the appliance. In certain cases, the main body of the device is, instead, fixed to the door, and the retention element is associated to the stationary structure.

In door-locking devices of the type referred to there is, in certain situations, the need to enable opening of the door of the appliance also when this is locked in the closing position by engagement between the locking member and the retention element: consider, for example, the case of malfunctioning of the electric actuator that actuates the mechanical part of the door-lock device, or else malfunctioning of the control system that controls the aforesaid device, or else again a fault in the wiring system of the appliance.

For this reason, some door-locking devices - such as the ones described in the aforesaid prior documents - are provided with a release arrangement, which may be actuated manually to bring about passage of the locking member from its condition of engagement to its condition of release so as to enable in any case opening of the door. This arrangement is basically conceived so as to enable a translation on the main body of the device of a rotation pin of the locking member, with respect to a working position thereof, so that the locking member can be released from the retention element. The aforesaid translation may be obtained by forcing opening of the door, i.e., applying to the door an opening force that is significantly greater than the minimum force necessary for opening the door itself, when it is not locked via the door-locking device.

The system for locking the door presupposes the co-operation of components that are associated to two different parts of the appliance, one of which (the door) is mounted movable with respect to the other (the stationary structure). In order to ensure proper operation of the door-locking device, the locking member and the corresponding retention element must hence be able to interact in a precise way, i.e., in accordance with the design specifications. This imposes a particular attention and precision in installation of the components in question on the respective parts of the appliance, as well as of the aforesaid parts with one another (the door with respect to the stationary structure). It is, however, possible that, on account of any production and/or assembly tolerances of the components involved, the relative position between the locking member of the device and the corresponding retention element is not optimal, or in any case is not such as to guarantee proper and safe operation of the device over time.

For these reasons, some door-locking devices are provided with a compensation arrangement, aimed at enabling the locking member to adapt its own working position as a function of the relative positions of assembly or installation between the parts involved (the main body of the device, the stationary structure of the appliance, the door and the retention element), in the case where these positions differ from the ones predefined in the design stage. In the case of the aforementioned document EP 1703212 A2, upon which the preamble of Claim 1 is based, the compensation arrangement is provided by the same release arrangement mentioned previously (or vice versa), and for this purpose comprises elastic means that constantly urge the rotation pin of the locking member downwards, into its working position on the main body, enabling a displacement of the pin for the purposes of compensation. The aforesaid elastic means also enable autonomous recovery of the working position of the pin of the locking member, after this has been induced to displace upwards following upon a compensation of the mechanical tolerances and/or a forced opening of the door.

Object and summary of the invention

The devices according to the lnown technique referred to above, albeit efficient, are relatively complicated to produce and are occasionally subject to anomalous displacements of the rotation pin of the locking member; for example, they are subject to imprecise inclinations thereof due to translations of different extent of the pin at its two ends. In this perspective, the present invention has the aim to provide a door-locking device for an electrical household appliance, provided with a release arrangement and/or a compensation arrangement, production of which is further simplified and reliability of which is increased. These and other aims still, which will emerge clearly hereinafter, are achieved according to the present invention, by a door-locking device for an electrical household appliance having the characteristics referred to in the annexed claims, which are to be understood as forming an integral part of the present description.

Brief description of the drawings

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

- Figures 1 and 2 are perspective schematic views of a door-locking device according to a possible embodiment of the invention;

- Figure 3 is a schematic top plan view of the device of Figures 1 and 2;

- Figure 4 is a partially exploded, partial and schematic view of two end portions of the device of Figures 1-3;

- Figure 5 is a schematic top plan view of an articulation arrangement of the device of Figures 1-3;

- Figures 6 and 7 are perspective schematic views from different angles of a component of the articulation arrangement of Figure 5;

- Figures 8 and 9 are cross-sectional views according to the lines VIII- VIII and IX-IX of Figure 5, with the articulation arrangement in a first condition;

- Figures 10 and 11 are cross-sectional views similar to those of Figures 8 and 9, with the articulation arrangement in a second condition;

- Figures 12, 13 and 14 are schematic views in side elevation of the device of Figures 1-3, in a first condition, a second condition, and a third condition;

- Figures 15 and 16 are a perspective schematic view and a schematic view in side elevation of the device of Figures 1-3, in a fourth condition;

- Figure 17 is a perspective schematic view of a door-locking device according to another embodiment of the invention;

- Figures 18 and 19 are a perspective schematic view and a schematic top plan view, respectively, of a door-locking device according to another embodiment of the invention;

- Figure 20 is a perspective schematic view of an assembly part of a device according to possible embodiments of the invention;

- Figures 21, 22, and 23 are schematic views in side elevation of the device of Figures 18-19, in a first condition, a second condition, and a third condition, respectively;

- Figures 24 and 25 are a perspective schematic view and a schematic view in side elevation of the device of Figures 18-19 in a fourth condition;

- Figure 26 is a perspective schematic view of a door-locking device according to another possible embodiment of the invention;

- Figure 27 is a perspective schematic view of a door-locking device according to another embodiment of the invention;

- Figures 28, 29, 30, and 31 are schematic views in side elevation of the device of Figure 27, in a first condition, a second condition, a third condition, and a fourth condition; and

- Figure 32 is a perspective view of an assembly component of a device according to possible embodiments of the invention.

Description of embodiments of the invention

Reference to "an embodiment", "one embodiment", "various embodiments", and the like, in the framework of the present description is intended to indicate that at least one particular configuration, structure, or characteristic described in relation to the embodiment or embodiments is comprised in at least one embodiment. Hence, phrases such as "in an embodiment", "in one embodiment", "in various embodiments", and the like that may be present in various points of this description do not necessarily refer to one and the same embodiment, but may instead refer to different embodiments. Moreover, particular conformations, structures, or characteristics defined in the framework of the present description may be combined in any adequate way in one or more embodiments, which may even be different from the ones represented. The reference numbers and spatial references (such as "top", "bottom", "upper", "lower", "up", "down", "front", "rear", "vertical", "horizontal", etc.) used herein, in particular with reference to the examples in the figures, are only for convenience and hence do not define the sphere of protection or the scope of the embodiments. The same reference numbers are used in the figures to designate elements that are similar or technically equivalent to one another.

With particular reference to Figures 1 to 4, designated as a whole by 1 is a door-locking device according to the invention, provided for use on an electrical household appliance equipped with a door or hatch. For the purposes of the present description, it will be assumed that the electrical household appliance is a cooking oven and that the device 1 is provided for locking the hatch or door of the oven in the respective closing condition, when an operating program is in progress, for example a program of pyrolytic self-cleaning.

The device 1 comprises a supporting body 2, which is to be secured to the stationary structure 100 of the oven, such as its cabinet or load -bearing frame, on a respective resting surface. In the figures, the stationary structure 100 is illustrated limitedly to a portion of a wall thereof, for example a horizontal wall, on which the body 2 is secured. Consequently, in the examples provided, the aforesaid resting surface - designated by P for example in Figures 12-14 and 16 - is defined by the aforesaid, preferably horizontal, wall, the surface being substantially parallel to the wall.

The body 2, which is preferably generally box-shaped, may be made of a single piece, for example a moulded plastic material, but not excluded from the scope of the invention is an embodiment thereof in a number of parts rendered fixed with respect to one another, possibly also via an articulated or at least in part movable coupling, for example in such a way that two parts of the body 2 will be movale with respect to one another. As may be seen in Figure 2, in the example, the body 2 comprises two side walls 2a, a rear wall 2b, and a lower or bottom wall 2c, which in the example is resting on the structure or wall 100.

The body 2 supports in a displaceable way a locking member, which is designed to co-operate with at least one retention element associated to the door of the oven, or defined therein. In the case exemplified, the locking member, designated by 3, is angularly rotatable and is, for example, made of metal material. The member 3 is preferably basically shaped like a hook; in the sequel of the present description, the member 3 will thus be identified as "hook", for simplicity.

In various embodiments, the hook 3 is hinged or pivoted to the body 2 via respective constraint means, preferably comprising a pin 4, which extends between two generally parallel portions of the side walls 2a, in a front area of the body 2, these wall portions being purposely provided with coaxial holes for the pin 4. The hook 3 is in this way able to turn or move angularly about an axis identified by the pin 4, this axis being designated by for example in Figure 3. The pin 4, which is preferably cylindrical and made of metal material, may be a component distinct from the body of the hook 3 and be inserted in a transverse through hole of the hook itself. In other embodiments, the pin 4 may be made up of two reliefs or appendages projecting from opposite sides of the hook 3, which are coaxial, or else the pin 4 may be made up of two reliefs or appendages projecting from the facing sides of the side walls 2a of the supporting body 2, which fit into corresponding lateral holes or seats in the hook 3.

The device 1 has an actuation system, which comprises an electric actuator 5 controllable for causing displacements of the hook 3. In the case exemplified, the actuator 5, preferably fixed on the body 2, consists of a rotary motor, provided with electrical terminals, designated by 5a only in Figure 1, for its electrical supply. The actuator 5 could, however, be of some other type, such as a linear actuator, for example an electromagnet or an actuator of a thermal or electrothermal type. The actuation system of the device 1 further comprises a transmission arrangement, designated as a whole by 6 for example in Figure 3, configured for transferring to the hook 3 an actuation imparted via the actuator 5.

The transmission arrangement 6, which is mounted on the supporting body

2, may be of any known type and, with reference to the case exemplified, is suitable for converting into angular movements of the hook 3 the movements of actuation produced by the actuator 5. For instance, in various embodiments, the transmission arrangement 6 may be of the type described in the aforementioned patents EP 1640493 A2 and EP 1703212 A2, the teachings of which in this regard are incorporated herein for reference. In this perspective, for example, to the shaft of the motor 5 there may be associated a cam, for example a three-lobed cam (see Figure 27, where such a shaft and such a cam are partially visible, designated by 5b and 5c), for producing displacement of a slider, designated by 6a in Figures 2- 3. The slider 6a is constrained to the body 2 so as to be able to slide linearly between two limit positions, and for this purpose the bottom wall 2c of the body 2 preferably defines appendages for positioning and guiding the slider itself. The end of the slider 6a opposite to the actuator 5 preferentially presents a front surface defining an inclined plane, designed to co-operate with a rear part of the hook 3 (this inclined plane may for example be seen in Figure 18, where it is not designated by any reference number).

Also the shape of the hook 3 may vary from the one exemplified in the figures, in view of its function of co-operating, on the one hand, with a retention element, and, on the other, with an actuation system. In embodiments of the type illustrated, the hook 3 has a generally arched rear portion (see, for example, Figure 18), having one end with rounded profile, designed to co-operate with the inclined surface of the slider 6a to convert a linear movement into an angular movement, as well as a front engagement portion (see, for example, Figures 1 and 12), designed to engage with a retention element that is fixed or defined on the door of the oven. In the figures, the door is illustrated with a solid line limitedly to the aforesaid retention element, which is designated by 7, and is represented in partially schematic form and with a dashed line only in some of the figures, where it is designated by 101. Preferentially, mounted in a position corresponding to the pin 4 of the hook 3 is a torsion spring 4a, the ends of which react, respectively, against the body 2 and the hook 3, in order to urge the latter into an inoperative position or release position relative to the retention element 7.

As has been said, the system for actuation of the hook 3, i.e., the type of actuator 5 and the corresponding transmission system 6, may be of any suitable type. It should also be noted that, for certain applications, the locking system comprising the device 1 could have a configuration of assembly that is opposite to the one illustrated, i.e., with the body 2 mounted on the door 101, according to a respective surface of lie or resting surface, and with the retention element 7 on the stationary structure 100.

In the case exemplified, the device 1 is further equipped with at least one sensor, such as the one designated by 8, for example, an optical sensor or else a magnetic sensor or else a microswitch, preferably of a normally closed type, which is connected to the control system of the oven. For this purpose, the device 1 may advantageously be equipped with a connector, such as the one designated by 9, for interfacing the aforesaid sensor to the control system of the oven. Switching of the sensor, for example using a microswitch, may be obtained by means of a corresponding actuation element, such as the slider 6a itself or a shaped rod constrained to the body 2 so as to be able to slide linearly.

In the case exemplified, the sensor 8, associated to which is a respective actuation or excitation rod 10, has the function of detecting whether the door 101 is in the correct closing position (even irrespective of the position of the hook 3) in order to supply to the control system of the oven a signal for enabling start of an operating program or a program of pyrolitic self-cleaning. In addition or as an alternative to the sensor 8, there may be provided a different or further sensor (for example, an electromechanical, or optical, or magnetic sensor) for detecting whether the hook 3 is in the correct position of locking of the door 101 and supplying thereby a signal for enabling start of a program, for example the program of pyrolitic self-cleaning: also such a sensor, like the one designated by 8' in Figures 2, 17 and 18, here in a position underneath the sensor 8, may comprise a microswitch, for example co-operating in a direct or indirect way with the slider 6a (for example, by a relief or cam thereof).

In the case of presence of the sensor 8 for detecting closing of the door 101 and a sensor 8' for detecting the position of the hook 3, both of these sensors concur in supplying to the control system of the oven the signals for enabling start of the operating program.

With reference to the case illustrated, in a position of correct closing of the door 101 (as, for example, in Figure 12), the door itself holds the rod 10 in a retracted position, countering the action of a spring (designated by 10a only in Figure 3). In this retracted position, the rod 10 keeps the sensor 8 in an enabling condition or a condition of closing of an electrical circuit, which enables supply of the actuator 5. In this condition, in the case where the user selects a program or a pyrolitic self-cleaning, the control system of the oven will supply the actuator 5, for the purposes of movement of the slider 6a and hence of the hook 3, to bring the latter into the respective operative position, or position of locking of the door (in the presence of the further sensor 8", this will be used by the control system for verifying the correct operative position of the hook 3). Instead, in the case where the door is open, or not properly closed, the rod 10 will occupy an advanced position, by virtue of the action of the corresponding spring 10a, in which position the sensor 8 will be in a safety condition or a condition of opening of the aforesaid circuit, thereby preventing supply of the actuator 5. In this condition, there is hence prevented start of the program or the pyrolitic self- cleaning, also in the case of a specific selection in this sense by the user (a similar safety condition is assumed by the sensor 8' for detecting the position of the hook 3, if the aforesaid sensor 8' does not detect the correct position of locking of the hook itself). Obviously, in other appliances, similar functions could be controlled directly by the electronic control circuit of the appliance, even without any intervention on the part of a user.

In Figure 12, the device 1 is represented in an inoperative condition, in which the hook 3 is not engaged with the element 7. In this condition, the door 101 may be brought from its closed position to its open position by manually exerting on the door itself a first opening force, indicated schematically by the arrow Fi of Figure 12. In various embodiments, the door 101 is articulated in its lower part to the stationary structure of the oven, via known hinges that include respective return springs, which tend to keep the door itself in its closed position. In embodiments of this type, then, the force Fi is the one that must be exerted manually on the door by a user to overcome the elastic reaction of the aforesaid return springs. More in general, the force Fi can be understood as the minimum force necessary that must be applied manually to the door by a user to cause opening thereof, when it is not locked by the hook 3.

In the condition illustrated in Figure 12, the torsion spring 4a - when envisaged - urges the hook 3 into the respective inoperative position or release position. Preferentially, the action of the spring 4a is such that, in this condition, the end of the rear portion of the hook 3 is resting on the bottom wall 2c of the body 2, given the retracted condition of the slider 6a (see what is described in EP 1703212 A2, in relation to operation of the corresponding actuation system). In the case illustrated in Figure 12, as has been said, the door 101 is in its closed position: in this way, the door 101 holds the rod 10 in the respective retracted position, countering the action of the spring 10a, so as to keep the sensor 8 in its enabling condition, as explained above.

In the case where the user selects, for example, a program of pyrolitic self- cleaning, the control system of the oven enables supply of the actuator 5 so that, via the transmission arrangement 6, the hook 3 is brought into the respective operative condition, in which the hook itself is engaged with the retention element 7: in this condition, as illustrated for example in Figure 13 (as well as in Figures 1-3), the hook 3 holds the door 101 in its closed position, also against application of the aforesaid opening force Fi.

With reference to the example illustrated, the actuator 5 is supplied in such a way that the slider 6a of the transmission system 6 advances towards the hook 3 (to the left, as viewed in Figure 12), preferably countering the action of a spring (such as the one designated by 6b only in Figure 3). Following upon advance of the slider 6a, its inclined front surface (Figure 18) can penetrate underneath the rounded end of the rear portion of the hook 3. In this way the hook 3 is induced to move angularly about its pin 4 (in a counterclockwise direction, as viewed in the figures), countering the action of the spring 4a. As has been said, reaching of the final position of the slider 6a, i.e., of the position of engagement or locking of the hook 3, can be detected via a purposely provided sensor (such as the one designated by 8').

Basically, then, the aforesaid angular movement of the hook 3 is such that its rear portion lifts, with consequent lowering of its front portion. The end of the front portion of the hook 3 then engages the retention element 7 so as to lock the door 101 in its closing position. In this condition, as represented in Figure 13, the pull or force Fi possibly exerted on the door does not enable opening of the latter. Of course, the shape of the retention element 7 may be different from the one illustrated by way of example.

The condition illustrated in Figure 13 is maintained throughout the operating program set by the user or by the control circuit of the apparatus. At the end of the program, the control system issues a command for new activation of the actuator 5 in order to obtain a movement of the transmission arrangement 6 opposite to the previous one, i.e., a retraction of the slider 6a (for example, under the action of the spring 6b of Figure 3), and hence return of the hook 3 into the position illustrated in Figure 12. The device 1 thus returns into the respective inoperative position, where the door 101 can be opened by the user by exerting the pull or force F\.

In various embodiments, the device 1 is equipped with a release arrangement, to be used in the case where there is the need to open the door 101 manually, even though the latter is at the moment locked via engagement of the hook 3 with the retention element 7. As will be seen, in various embodiments, the aforesaid arrangement may be used - in addition or as an alternative - for the purposes of compensation of possible production and/or assembly tolerances so that the above arrangement could also be defined as "release and/or compensation arrangement": described in what follows, for clarity of exposition, are first the functions of release and then the functions of compensation of the arrangement in question, which will also be identified for simplicity as "release arrangement" and "compensation arrangement" according to the cases described.

As in the cases described in EP 1640493 A2 and EP 1703212 A2, the aforesaid release arrangement may be actuated for enabling passage of the hook 3 from its operative condition to a second inoperative condition, in which the hook 3 is not engaged with the retention element 7. More in particular, the release arrangement is prearranged for enabling temporary displacement of the hook 3 from its locking position, i.e., from the operative condition of Figure 13, to a release position, illustrated in Figure 14, where the hook 3 is in the aforesaid second inoperative condition. Reaching of the second inoperative condition may be obtained following upon manual application to the door 101 of a second force, indicated schematically by F ₂ in Figure 14, which is greater than the force Fi mentioned previously. In various embodiments, such as the one represented, the hook 3 and the retention element 7 have co-operating profiles, shaped in such a way that, following upon the aforesaid application of the force F ₂ , a translation upwards of the hook 3 is obtained (allowed by an angular displacement of the body 2 or of a part thereof), until it exits from the corresponding engagement seat of the retention element 7.

According to an aspect of the invention, the release arrangement of the door-locking device 1 comprises an articulation arrangement (where this definition refers to arrangements provided with a fulcrum or some other type of hinge or articulation), which is prearranged for enabling the supporting body 2 (or, as will be seen, at least a first part of the body 2 associated to which are at least the constraint means 4 of the hook 3) to perform angular displacements relative to the stationary structure 100. These angular movements occur about a second axis of rotation - denoted schematically by X ₂ in Figures 3 and 5 - that is substantially parallel to the resting plane P identified by the structure or wall 100 and/or substantially parallel to the axis Xi of rotation of the hook 3, so as to vary the distance between the axis Xi of the hook 3 and the resting plane P or the structure 100 that defines it. Preferentially, these angular displacements take place starting from a working or initial angular position of the body 2, in which it lies according to the aforesaid resting plane P. The variations with respect to the above initial position occur following upon manual application to the door 101 of the aforesaid second opening force (or, as will be seen, occur for the purposes of compensation of dimensional tolerances or differences).

Preferentially, the release arrangement of the device 1 is also prearranged for elastically urging the supporting body 2 (or the aforesaid first part of the body 2) towards the resting plane P. As has been said, preferentially but not necessarily, the supporting body 2, or its aforementioned first part, are able to perform the aforesaid angular displacements about a second axis of rotation X ₂ , which is substantially parallel to the axis Xi of rotation of the hook 3, the distance between the axes of rotation Xi and X ₂ being substantially the same in the various operating conditions.

The axis of rotation X ₂ is here referred to as being "generally" or

"substantially" parallel to the resting plane P and/or to the axis Xi given that, during installation or operation of the device, also minimal movements of rocking or inclination of the aforesaid axis with respect to the plane P are possible. Similar considerations obviously also apply to the axis Xi.

In various embodiments, such as the one represented in Figures 1-16, the hook 3 is set in a position corresponding to a generally front or distal portion of the supporting body 2, whereas the articulation arrangement, designated as a whole by 20, is set in a position corresponding to a generally rear or proximal portion of the supporting body 2. In preferential embodiments, the articulation arrangement 20 and the corresponding axis X ₂ are hence set in a position substantially opposite to the position of the hook 3 and of the corresponding pin 4 or axis Xi.

With reference in particular to Figures 2-5 and 12, the articulation arrangement 20 comprises a movable part 21, which is coupled to a fixed part 22. In various embodiments, the movable part 21 is defined by the supporting body 2, but not excluded from the scope of the invention is the case of a movable part configured as a distinct part fixed to the body 2. Likewise, the fixed part 22 may be configured as an element fixed to the structure or wall 100, or else - as will be seen in relation to other embodiments - be directly defined in the structure or wall 100.

With reference in particular to Figures 4-5, in the case exemplified, the movable part 21 comprises at least one movable hinge element 21a, in particular of a substantially rigid type, which is preferably made of a single piece with the body 2, very preferably projecting from its rear wall 2b. In various embodiments, the movable hinge element 21a is shaped to create in an end area thereof a profile in relief, which is at least in part circular or arched. Defined for this purpose in the rear area of the movable part 21a is a transverse formation or shape, which forms a sort of fulcrum or hingepin. Preferentially, this shape has an approximately cylindrical outer profile or, as in the case exemplified, is defined by at least two opposed semi-cylindrical portions, which may also have different diameters: these two semi-cylindrical portions are designated by 21ai and 21a ₂ in Figures 4 and 9, respectively.

Defined centrally in the same area of the movable element 21a is an axial through seat, designated by 21a ₃ in Figures 4 and 8, which also passes through the aforesaid cylindrical transverse formation 21ai-21a ₂ . Preferentially, the seat 21a ₃ has a diameter or cross- sectional dimension greater than the diameter or cross- sectional dimension of the formation 21ai-21a ₂ .

As may be seen in Figures 5-9, the fixed part 22 comprises at least one fixed hinge element 23, which is configured for constraining the aforesaid rear end area of the hinge element 21a to the stationary structure 100, in particular via at least one screw 24 or similar fixing member (for example, a rivet). In the example illustrated, the fixed element 23 has an upper part 23a configured substantially like a small shaped plate, projecting underneath which is a relief 23b, which can be received in the through seat 21a ₃ of the fixed hinge element 21a. The relief 23b and the corresponding seat 21a ₃ preferentially have a substantially circular cross section and are coupled in a slack way or with play.

In various embodiments, the lower face of the part 23a of the fixed hinge element 23 defines a transverse seat 23d, for example a substantially semi- cylindrical seat, in which there may be received a substantially complementary part of the movable element 21a, here represented by the upper semi-cylindrical portion 21ai of the formation 21ai-21a ₂ .

The upper part of the fixed hinge element 23 preferably also includes front slits 23e for the passage of stiffening ribbings of the movable hinge element 21a (these ribbings being designated by 21b in Figures 4-5 and 8-9). The movable hinge element 21 and the fixed hinge element 23 preferably envisage means for mutual engagement, for example to keep the two items in question in position during production steps (for example, prior to fixing with the screw or rivet 24). In the case exemplified, these mutual-engagement means - which in any case enable mutual angular movement between the elements 21 and 23 - comprise lateral reliefs or teeth 23f of the upper part 23a of the element 23, suitable for engagement in corresponding seats provided on the two opposite sides of the movable element 21a, in particular on the two sides of the formation 21ai-21a ₂ .

Assembly of the articulation arrangement 20 is very simple. In the first place, the fixed element 23 is set on top of the corresponding end area of the movable element 21a so that the relief 23b penetrates into the seat 21a ₃ and the semi-cylindrical profile of the upper portion 21ai of the formation 21ai-21a ₂ couples with the corresponding seat 23d of the fixed element 23. With this operation, the ribbings 21b of the movable element 21 are received in the corresponding slits 23e of the upper part 23a of the fixed element, and the lateral teeth 23f of the upper part of the fixed element 23 couple with the corresponding lateral seats of the movable element 21a. As may be seen, for example, in Figure 8, the cross-sectional dimension or diameter of the through axial seat 21a ₃ of the movable element 21a is greater than the corresponding cross -sectional dimension or diameter of the relief 23b of the fixed element 23, whereas the length of the relief 23b is greater than that of the corresponding seat 21a ₃ .

The element 23 is then secured to the stationary structure 100 by tightening home the screw 24 so that the lower end of the relief 23b bears upon the structure 100. For this purpose, provided in the structure 100 is a hole for the screw 24, which may even be of a self -tapping type (this also applies to the other screws or the like referred to hereinafter). Following upon tightening of the screw 24, the lower end of the relief 23b hence rests on the structure or wall 100, with the head of the screw 24 that holds the element 23 in the fixing position, as may be seen, for example, in Figures 8-9. The height of the relief 23b is such that, following upon fixing with the screw 24 or the like, the semi-cylindrical profile of the lower portion 21a ₂ of the formation 21ai-21a ₂ rests on the structure or wall 100, as may be seen for example in Figure 9. Preferentially, then, the movable part 21a is not free to perform axial movements along the relief 23b.

Possibly, in order to favour positioning of the parts, the lower end of the relief 23b of the fixed element 23 may be shaped (for example, convex) for coupling in a corresponding seat defined in the structure 100, as may be seen, for example, in Figure 8 (this seat may be a flare of the type commonly provided for receiving partially the head of a screw).

Given that the diameter of the through seat 21a ₃ of the movable hinge element 21a is greater than the diameter of the relief 23b of the fixed hinge element 23, a certain angular movement of the movable part 21 with respect to the fixed part 22 is allowed.

Following upon the assembly of the articulation arrangement 20, the supporting body 2 is then secured in its rear part to the stationary structure 100, but so as to be able to perform angular movements about the axis X ₂ . This is allowed by the different diameters of the relief 23b and the seat 21a ₃ and by the possibility of rotation of the movable hinge element 21a (in particular, of its formation 21ai-21a ₂ ) with respect to the fixed hinge element 23 (in particular, with respect to its seat 23d). The movements about the axis X ₂ allowed by the articulation arrangement 20 occur starting from a working or initial angular position of the body 2, such as the one that may be seen in Figures 8-9 and 12, where the body itself 2 lies in the resting plane P. With reference to the aforesaid figures, these movements occur in the clockwise direction. Figures 10- 11 illustrate a condition in which the part 21 is rotated with respect to the fixed part 22, about the axis X ₂ of Figure 5. Passage from the position of Figures 8-9 to that of Figures 10-11 is favoured by the presence of the semi-circular profile of the lower portion 21a ₂ of the formation 21ai-21a ₂ , which can slide in rotation on the wall 100.

Preferentially, the release arrangement of the device 1 is prearranged for urging the supporting body 2 elastically towards the aforesaid working or initial angular position, i.e., towards the resting plane P. For this purpose, the release arrangement may comprise a restoring arrangement, for the articulation arrangement 20, suitable for constantly urging the body 2 towards its working or initial angular position.

With reference to the example of embodiment of Figures 1- 16, the restoring arrangement, designated as a whole by 30, is associated to the supporting body 2 in a position intermediate with respect to its front portion, which is provided with the hook 3, and to its rear portion, which is provided with the articulation arrangement 20. In various embodiments, the restoring arrangement is in a position close to the hook 3, preferably in a position generally set alongside one end of the hook 3, in particular the controlled end on which the transmission arrangement 6 operates.

In various embodiments, the arrangement 30 comprises at least one guiding member, which is provided for guiding the deformations or the displacements of an elastic element and/or for guiding the angular displacements of the body 2 - in particular, its front portion - about the axis X ₂ , as well as preventing lateral displacements thereof (for example, about the vertical axis identified by the screw 24) or undesired longitudinal displacements. For this purpose, in various embodiments, the body 2 is slidably constrained - in particular, in its front portion - to the guiding member, which is preferably configured as component distinct from the body itself (possibly, however, forming part thereof).

In various embodiments, the guiding member is pre-arranged for fixing to the stationary structure and supports a respective elastic element, preferably a helical spring, in particular made of metal, with the above elastic element that interacts between the guiding member and the supporting body for urging the latter towards its working or initial angular position. In other embodiments, the elastic element is of some other type, of a different shape, such as a leaf-spring element and/or an element made of a different material, for example an elastomer or an element made of elastically deformable thermoplastic material.

In the example illustrated (see Figure 4), the guiding member, designated by 31, comprises a base or lower part 32, which is configured for being secured to the stationary structure 100, in particular via a screw 33 or similar fixing member (for example, a rivet). The member 31 then comprises an upright part 34, which is generally elongated, preferably but not necessarily of a substantially cylindrical shape. Preferably, the member 31 is made of a single piece, for example obtained via moulding of plastic or metal material. As an alternative, the upright part 34 could be a distinct component, for example made of metal, with the base part 32 made of plastic material overmoulded in a position corresponding to the lower end of the upright part.

The upright part 34 extends longitudinally upwards and is preferentially slidably coupled to the body 2, or in any case coupled in such a way that the body 2 can perform movements with respect to the plane P only in a substantially vertical direction or angular movements with respect to the axis X ₂ . In various embodiments, such as the one exemplified, the body 2 has - preferentially substantially at a side wall 2a thereof - a hole or through seat, which is substantially vertical (possibly inclined or arched). Slidably engaged in this through seat, designated by 35 only in Figures 1 and 4, is the upright part 34 of the member 31. In various embodiments, the upright part 34 is slightly arched backwards, so as to be able to guide precisely the angular displacements allowed for the body 2.

Preferentially, the body 2 defines, in its lower wall 2c and/or in the side wall 2a where the guide member 31 is located, a housing, which may be seen only partially in Figures 14-16, where it is designated by 2d, for positioning of the member 31. In the case exemplified, the housing 2d is configured for receiving at least a portion of the base part 32, as well as enabling another portion of the base part 32 to project laterally from the body 2 in order to enable fixing thereof to the structure 100 via the screw 33.

Fitted on the portion of the upright part 34 that projects at the top of the through seat 35 is a helical spring, designated by 36. The upper end of the spring 36 bears upon a suitable arrest element 37 associated to the upright 34 or defined thereby, for example a stop ring, as in the case illustrated. The lower end of the spring 36 bears, instead, upon the body 2, in the area 35a (Figure 4) that surrounds the through seat 35, as may be seen, for example, in Figure 1. In this way, the body 2 is urged elastically by the spring 36 towards the structure 100, i.e., towards its working or initial angular position, i.e., towards the resting plane P. Hence, preferably, the spring 36 bears upon or operates in thrust on an upper area or surface 35a of the body 2, which is set at a distance from the plane P or the lower wall 2c of the body 2. Preferably, the upper area or surface 35a is set at a height greater than that of the rotation pin 4 of the hook 3.

Assume that the device 1 is set in the operative condition illustrated in

Figure 13, i.e., with the door 101 that is locked in a closed position via the hook 3. In this situation, if for any cause (such as malfunctioning of the control system of the oven or a power black-out), the actuator 5 is not in a condition to be made to function in the way described above, release of the device 1 can be obtained manually, by virtue of the release arrangement, here including the articulation arrangement 20 and the restoring arrangement 30.

For this purpose, a pull must be exerted on the door 101, i.e., a force applied in the opening direction of the door itself, as indicated schematically by the arrow F ₂ of Figure 14. The system is conceived in such a way that the force F ₂ necessary to obtain manual release is higher than the minimum force Fi required for opening of the door 101 in the usual opening condition of Figure 12, preferably a force such as to satisfy safety parameters. Merely by way of example, to the door 101 there must be applied a pulling force F ₂ greater than 9 kg or 90 N (safety value), whereas the force Fi usually required for opening, in the condition of Figure 12, is approximately just 3-5 kg.

The relative position between the hook 3 and the retention element 7 is such that the torque exerted on the door 101 determines a vertical component of force on the hook 3, with the front end of the latter that will tend to move angularly in a clockwise direction or upwards, as viewed in the figures. As mentioned, preferentially, the surfaces co-operating with one another of the front end of the hook 3 and of the retention element 7 are shaped in order to obtain the components of force necessary for the aforesaid movement of the hook 3: in the case exemplified, the front end of the hook has a generally rounded surface, which is able to slide on a generally vertical inclined surface of the element 7.

As has been said, in the situation under examination (device 1 that locks the door) the rear end of the hook 3 is resting on the upper surface of the slider 6a (see Figure 2). Consequently, following upon the aforesaid vertical component of force that is applied on the rear end of the hook 3 (approximately 1.33 kg, with reference to an example of pulling force F ₂ of approximately 12 kg, higher than the safety value of 9 kg exemplified above), the body 2 is urged as a whole upwards, with the body itself that - thanks to the presence of the articulation arrangement 20 - can move angularly about the axis X ₂ (in a clockwise direction, as viewed in Figures 1-16), also constrained and guided in this movement by the restoring arrangement, and especially by the coupling between the upright part 34 and the corresponding through seat 35 of the body 2, as explained previously. The angular movement of the body 2 is allowed by the movable part 21 of the articulation 21-22 and occurs with respect to the fixed part 22, as well as with respect to the rear anchorage point represented by the screw 24.

This angular displacement upwards of the body 2, which occurs against the action of the spring 36 of the restoring arrangement 30, determines a corresponding displacement of the pin 4 and of the hook 3 associated thereto. Also the front portion of the hook 3 hence displaces upwards, freeing itself from the retention element 7, as may be seen in Figure 14, thus releasing the door 101 , which can thus be opened. As may be noted from the comparison between Figures 13 and 14, in this step the body 2 comes to assume temporarily a position inclined upwards with respect to the initial one, relative to the stationary structure 100, i.e., with the axis X ₁ that is now at a greater distance from the resting plane P.

Indicatively, the angular movements allowed for the body 2 about the axis X ₂ may be comprised between 0° and 5°, with respect to the resting plane P or to the wall 100.

Return of the body 2 into the initial angular position then occurs in an automatic or autonomous way, by virtue of the elastic reaction of the spring 36, which will again push the body 2 downwards, until it is made to return into the initial angular position of Figure 12 or Figure 13, i.e., in the resting plane P.

In Figures 1-4 and 12-14, the device 1 is represented in a condition of correct relative assembly of the components involved - i.e., the stationary structure 100, the door 101, the supporting body 2, and the retention element 7 - namely, according to the design specifications of the oven. Figures 15 and 16 refer instead to a situation where, for example on account of production and/or assembly tolerances, one or more of the aforesaid components is/are assembled in a slightly different way with respect to what is shown Figures 1-4 and 12-13. In particular, in the case exemplified, in the closed position of the door 101, the upper end of the door itself and/or the retention element 7 is/are located at a height slightly greater than in Figures 1-4 and 12- 13.

Also in this situation of assembly, following upon activation of the actuator 5, the device passes from the inoperative condition (see Figure 12) to the operative condition (see Figure 13). At a certain point of the angular movement of the hook 3, its front portion hence comes to rest on a bottom surface 7a of the retention element 7, but earlier than in the case of Figure 13. In the continuation of the angular movement of the hook 3 brought about by the actuation system 5-6, as described previously with reference to Figure 14, a load is applied to the pin 4 such as to bring about an angular movement upwards of the body 2, about the axis X ₂ , for example up to the position that may be seen in Figure 16, which also in this case is substantially inclined with respect to that of Figure 13 (absence of production and/or assembly tolerances), i.e., with respect to the plane of lie P defined by the structure or wall 100. The position thus reached by the pin 4 and by the hook 3 relative to the retention element is in any case such as to guarantee proper operation of the device 1. Also in this operating mode, there hence occurs a variation (an increase) of the distance of the axis Xi from the resting plane P.

Consequently, as may be appreciated, the device 1 according to the invention is equipped with a compensation arrangement, which enables the supporting body 2 to adapt its angular working position as a function of the effective relative positions of assembly or installation of the body itself, the stationary structure 100, the door 101 and the retention element 7, in the case where these effective positions differ from pre-defined or design positions. In other words, hence, it is possible to compensate any imprecise relative positioning of the parts involved, in particular in height, guaranteeing precise and safe operation of the device 1 over time. As may be appreciated, in the specific case exemplified, the articulation arrangement 20 and restoring arrangement 30 of the compensation arrangement are the same as the release arrangement that, if the case of need, enables manual release of the door 101.

Represented schematically in Figure 17 is a variant embodiment in which the articulation arrangement 20 has a movable part 21 comprising two hinge elements 21a, which extend generally parallel to one another. In this case, two fixed parts 22 and two corresponding screws 24 or the like are provided. Of course, the two parts 21 and/or 22 could be replaced by a single part 21 and/or 22 that is wider than the ones exemplified.

According to a variant not represented, the two movable parts 21 and the two fixed parts 22 could be opposed to one another and/or located on side walls 2a of the supporting body 2, albeit at an end portion of the body 2 opposite to the one that houses the hook 3.

Figure 17 likewise exemplifies possible embodiments in which a device according to the invention comprises two restoring arrangements produced in a way similar to what has been described with reference to Figures 1- 16, i.e., with two guiding members 31, associated to two respective springs 36 and two fixing rings 37, these members 31 sliding in respective seats provided in opposed positions of the supporting body 2, preferably on opposite sides of the hook 3. In the case exemplified in Figure 17, the two members 31 are associated each to a respective side wall 2a of the supporting body 2. Operation of the device 1 of Figure 17 is similar to the one described previously with reference to Figures 1- 16.

In various embodiments, the device according to the invention has a restoring arrangement which is located at, or in the proximity of, the articulation arrangement, or which comprises at least one elastic element mounted or operative at, or in the proximity of, the articulation arrangement. Preferentially, the aforesaid elastic element is a torsion spring that interacts between the supporting body, or a movable hinge part, and the structure 100 on which the body is mounted. An embodiment of this type is exemplified in Figures 18-25.

With initial reference to Figures 18 and 19, also in this embodiment the articulation arrangement 20 envisaged on the rear or proximal portion of the body

2 comprises a movable hinge element 211, which is engaged in a fixed hinge part 22i fixed with respect to the structure 100. In this case, the movable hinge element 211 is substantially configured as a hingepin, preferably at least in part cylindrical or rounded, which extends transverse to the longitudinal direction of the body 2. The element 211 is preferably - but not necessarily - defined by a formation that projects from the rear wall 2b of the body 2, made of a single piece with the latter. The fixed hinge part 22i comprises, instead, an element generally arched backwards, or in any case shaped so as to define a seat for the hingepin 211, this seat being here open in a direction opposite to the hook 3. As may be appreciated, the pin element 211 may be housed with the possibility of angular movement within the seat defined by the element 221, with the pin element that identifies the axis of rotation X ₂ .

The fixed hinge part 22i may advantageously be defined via shearing and deformation of an area of the stationary structure 100, i.e., of the wall - preferably made of sheet metal, for example horizontal - on which the device 1 is secured; such an embodiment is exemplified in Figure 20.

In embodiments where an elastic element of the restoring arrangement is installed in a position corresponding to the articulation arrangement - as, for example, in Figures 18- 19 - it is preferable to provide a constraining and/or guiding arrangement, for constraining laterally the supporting body 2 in at least one area thereof, for example comprised between the hook 3 and the articulation arrangement 20, and guiding the angular displacements thereof about the axis X ₂ .

In the case exemplified, the constraining and/or guiding arrangement comprises two elements or walls 40 that rise from the structure 100 at the two side walls 2a of the body 2, these walls 40 being preferably parallel to one another and with respect to corresponding portions of the walls 2a. The distance between the constraining and/or guiding walls 40 is only slightly greater than the distance of the corresponding portions of the walls 2a. In this way, the walls 40 prevent significant lateral movements of the body 2, however enabling the latter to perform the required angular movements. Preferably, the walls 40 guide the supporting body 2 also so as to prevent it from possibly tilting laterally, towards the walls 2a. Also the constraining and/or guiding arrangement, here including the walls 40, may be defined in the stationary structure 100, as exemplified in Figure 20.

The restoring arrangement of the device of Figures 18-19 comprises an elastic element designated as a whole by 361 interacting between the body 2 and the structure or wall 100 so as to urge the former towards the latter. In the example, the elastic element 36i is a torsion spring. Preferentially, the spring 36i is shaped so as to define a first end portion 36a, bearing upon the structure 100, and a second end portion including two parallel spring arms 36b (only one of which is visible in the figures), each of which bears upon the body 2a, preferably in a corresponding seat or engagement formation 2e (only one of which is visible in the figures). The spring 361 moreover has an intermediate portion that includes two stretches wound in a helix, designated by 36c, substantially coaxial with respect to one another and each fitted on a corresponding pin element 34i, which extends generally parallel to the hingepin 211 or to the axis X ₂ . The two pin elements 34i, preferably opposed to one another or with axis in common, may advantageously be defined by the supporting body 2, in particular by the same formation that forms the hingepin 211. The spring 36i is hence shaped in such a way that its end portion 36a tends to push downwards, on the structure 100, and also the two branches 36b of the other end thereof urge the supporting body 2 downwards.

Given that, in the case exemplified, the seat defined by the fixed hinge element 22i is open at the rear, it is preferable to provide at least one element that counters any possible displacements backwards or retractions of the body 2 as a whole. In the case exemplified, provided on the structure 100, for this purpose, is an arrest element 50, bearing upon which is the portion 36a of the spring 36i, consequently preventing any retraction of the elements 341 and of the body 2. Also such an arrest element 50 can be defined in the stationary structure 100, as exemplified in Figure 20. Obviously possible are other solutions for preventing any longitudinal displacements backwards of the body 2, for example by providing or fixing purposely designed arrest brackets on the structure 100, or again by providing the hinge element 22i fixed so as to prevent the possibility of exit of the hingepin 211 therefrom (for example, after coupling between the pin 211 and the element 22i, the upper end of the arched wall that forms the latter could be bent downwards, to prevent exit of the pin 211, allowing, however, angular movements thereof).

Operation of the device 1 of Figures 18-25 is substantially similar to what has been described previously with reference to Figures 1-16.

Figure 21 illustrates a condition corresponding to that of Figure 12, i.e., with the door 101 closed and the device 1 in an inoperative condition, where the hook 3 does not engage the retention element 7. The body 2 as a whole is in the "design" working angular position, where the body itself rests entirely on the structure 100.

Figure 22 illustrates a condition corresponding to that of Figure 13, i.e., with the door 101 closed and the device 1 in the operative condition in which the hook 3 engages the retention element 7. Also in this condition, the body 2 as a whole is in its "nominal" angular working position, where the body itself lies in the resting plane P defined by the structure 100.

Figure 23 illustrates a condition corresponding to that of Figure 14, where the actuation system of the device 1 holds the hook 3 in its locking position, but applied to the door 101 is the force F ₂ necessary to obtain manual release of the device itself, i.e., opening of the door. As explained, in this way, the body 2 as a whole is induced to make an angular movement upwards, about the axis X ₂ , countering the reaction of the spring 361, this angular movement being of an amount such as to enable disengagement between the hook 3 and the element 7. After release of the door, the body 2 can return into its starting angular position, thanks to the action of the restoring arrangement 30.

Figures 24 and 25 illustrate a condition corresponding to that of Figures 15 and 16, where - on account of production and/or assembly tolerances between the components - the upper end of the door 101 and/or the retention element 7 are located at a height slightly greater than in Figures 21 or 22. Following upon activation of the actuator 5, applied to the hook 3, and consequently to the pin 4, is a load or force that is transmitted to the body 2, thereby bringing about angular movement upwards of the body itself, about the axis X ₂ , i.e., in a position substantially inclined with respect to the case illustrated in Figure 22, in the absence of production and/or assembly tolerances of the components.

Figure 26 exemplifies the case of a device 1 having an articulation arrangement 20 in which the movable hinge part includes a rotatable hingepin 211, as in the case of Figures 18-25, but in which a restoring arrangement 30 is provided that is associated to the body 2 in an area intermediate between the hook 3 and the articulation arrangement 20. The movable hinge part in this case comprises two elements 22i, substantially similar to that of Figures 18-25, in positions generally parallel to one another. In the case exemplified, the restoring arrangement 30 is of a type similar to the one described with reference to Figures

1-16. Obviously, this arrangement could also comprise two guide members 31, as in the case of Figure 17.

It will be appreciated that the type of embodiment of the articulation arrangement 20 of Figures 18-25 and 26 also enables prevention of possible movements of the rear portion of the body 2, both in the horizontal direction and in the vertical direction, as well as about a vertical axis.

In possible embodiments of the invention, the supporting body of the device comprises two parts joined together by means of an articulation arrangement, where associated to a first part of the body are the constraint means of the locking member, here exemplified by the pin 4 of the hook 3, and the second part of the body is fixed to the stationary structure.

Such a case is exemplified in Figures 27-31, where the supporting body 2 comprises a front part 2i, which carries at least the pin 4 and the hook 3, and preferably also part of the transmission system 6, and is able to perform angular movements with respect to the structure 100, as well as a rear part 2 ₂ , which is instead secured in a fixed position to the structure 100, where these two parts 2i and 2 ₂ are joined together by means of an articulation arrangement 20. In the case illustrated, defined at the rear end of the part 2 ₂ are one or more brackets 2f, for anchorage to the structure or wall 100 via screws 60 or similar fixing members (for example, rivets).

The articulation arrangement may be of any type, for example comprising a fixed hinge part and a movable hinge part, associated to the two body parts 2i and 2 ₂ or defined by the latter, which are coupled together, for example via a pin or an articulation, or else comprising - as in the case exemplified - an elastic or flexible hinge: for this purpose, the body 2 may be made of a suitable polymer, such as a mouldable plastic material, for example a thermoplastic material. In various embodiments, for example, such a body 2 may be moulded with walls of a first thickness in order to provide one or more substantially rigid parts 2 _\ , and 2 ₂ of the supporting body, whereas one or more walls or formations of smaller thickness, which connect the two parts 2 _\ , and 2 ₂ , form an articulation or hinge that is at least in part flexible, or in any case designed to enable angular movement of one part relative to the other part. The elastic or flexible hinge could possibly also be made of a polymer or plastic material different from that of the two parts 2i, and 2 ₂ , such as an elastomer, preferably overmoulded on, or co-moulded to, the substantially rigid parts 2 _\ , 2 ₂ of the supporting body 2 (or in any case fixed or welded or glued or hooked to at least one of the aforesaid parts 2 _\ , 2 ₂ ).

With reference to the example of Figures 27-31, the articulation arrangement 20 is made integrally with a portion of the first body part 2 _\ and a portion of the second body part 2 ₂ (here a rear portion and a front portion of the parts 2 _\ and 2 ₂ , respectively), and comprises at least one generally horizontal transverse wall 21 ₂ , which joins the two parts of the body 2. In order to favour elastic deformation and identify the axis X ₂ , in the wall 21 ₂ there may be defined a recess that traverses the wall itself throughout its width or part thereof. Obviously, instead of a single wall there may be provided a plurality of walls narrower than the one here designated by 21 ₂ , for example parallel to one another, which join the two body parts 2i and 2 _2. . In various embodiments, provided in the wall 21 ₂ are a number of recesses and/or a number of stretches of different thickness, each of which could also define a respective axis of rotation (i.e., a number of axes of rotation could be provided, the combination of which could in any case be functionally equivalent to a single axis of rotation X ₂ of the type described previously). For the purposes of the invention and with reference to the various examples, the definition of "second axis of rotation X ₂ " is hence considered as comprising even a number of axes of rotation or fulcrum axes adjacent or close to one another, or in any case comprised in the area of the articulation arrangement.

In an embodiment of the type illustrated, the rear body part 2 ₂ forms or basically comprises a fixed hinge part, whereas the wall 21 ₂ forms or basically comprises a movable or elastically deformable hinge part, with the body part 2i that is able to move angularly about the axis X ₂ .

It will be appreciated that, by virtue of its capacity of bending or elastic deformation, the wall 21 ₂ enables also the functions of the restoring arrangements described previously to be provided. On the other hand, in possible embodiments, to the movable body part 2i there can be associated a restoring arrangement of its own, for example of the same type as the one designated by 30 in Figures 1-16. As an alternative, according to an example (not represented), the two body parts 2i and 2 ₂ could be distinct from one another and joined by a hinge provided with a pin or an articulation, to which a torsional return spring could be associated.

In the example of Figures 27-31, a constraint and/or guide arrangement is also provided, for lateral constraint of the body part 2i and for guiding the angular displacements thereof. In the case exemplified, this arrangement is similar to the one described with reference to Figures 18-25, including lateral constraint and guide walls 40, but other solutions are obviously possible for this purpose, as mentioned previously. For instance, there may be associated to the body part 2i a restoring arrangement 30 of the type described with reference to Figures 1-16, which, as explained, would also be suitable for constraining and guiding the angular displacements of the aforesaid body part. Operation of the device 1 of Figures 27-31 is substantially similar to what has been described previously with reference to Figures 1-16 and 18-25.

Figure 28 illustrates an inoperative condition of the device 1, corresponding to that of Figures 12 and 21, whereas Figure 29 illustrates an operative condition corresponding to that of Figures 13 and 22. Figure 30 illustrates, instead, a condition corresponding to that of Figures 14 and 23: the actuation system of the device 1 holds the hook 3 in its locking position, but applied to the door 101 is the force F ₂ necessary to obtain manual release of the device itself. The body part 2i, associated to which are at least the pin 4 and the hook 3, and preferably also part of the transmission system 6, is induced to perform an angular movement upwards, about the axis X ₂ , tilting with respect to the resting plane P. This angular movement, i.e., the increase of the distance of the axis Xi from the resting plane P is of an amount such as to enable disengagement between the hook 3 and the element 7. After release of the door 101, the body part 2i can return into its starting angular position, where it rests on the structure 100, in particular thanks to the elastic reaction of the wall 21 ₂ , which in the example also functions as restoring arrangement (as has been said, on the other hand, a distinct restoring arrangement 30 may be provided).

Figure 31 illustrates a condition corresponding to that of Figures 16 and 25, where there exist production and/or assembly tolerances between the components, such that the upper end of the door 101 and/or the retention element 7 are located at a height slightly greater than in Figures 27-29. Also in this case, following upon activation of the actuator 5, applied to the pin 4 is a load or force that determines angular movement upwards of the body part 2 _\ , about the axis X ₂ , in a position substantially inclined with respect to the case illustrated in Figure 29

(absence of production and/or assembly tolerances of the components).

From what has been described with reference to Figures 27-31, it will be appreciated that the angular movements described with reference to the embodiments of Figures 1-26 may also regard just the part of the body 2, associated to which is the hook 3, instead of the body 2 as a whole.

With specific reference to the case of Figures 27-31, or more in general of a supporting body that comprises two parts joined together by means of an articulation arrangement, the actuation system will be devised for enabling angular movements upwards and downwards of the body part that carries at least the hook 3 and possibly at least part of the transmission system 6. In the example, the rear end 6c (Figure 29) of the rod 6a of the transmission system 6 is shaped so as to be able to translate and/or tilt relative to the surface of the cam 5c, following upon the angular movements of the body part 2i (mounted on which is the rod 6a) with respect to the body part 2 ₂ (mounted on which is the actuator 5).

In embodiments described previously, some elements of the device according to the invention are defined by the structure or wall 100, such as at least one fixed hinge part 221, the lateral constraint walls 40, and the arrest element 50 (see Figure 20). As already mentioned, however, one or more of these elements could also be configured as components distinct from the structure and fixed to the latter. Figure 32 exemplifies the case of a sub-structure or base 70 for the body 2, which is to be fixed to the structure or wall 100 (for example, via screws or rivets, or via engagement or welding or gluing) and on which there is then anchored and/or constrained and/or guided the body 2 or an angularly movable part thereof, such as the part 2i of Figures 27-31. In the example, the base 70 is shaped substantially like a plate, for example made of metal, and is shaped so as to define a fixed hinge part 221, two lateral constraint walls 40, and a rear arrest element 50.

From what has been described above, it may be appreciated how the door- locking device according to the invention is simple and economically advantageous to produce. The means that enable manual release of the device and/or that afford compensation of any imprecision of assembly do not entail, in their operation, any translation of the constraint means (the pin 4) of the locking member (the hook 3) on the supporting body 2 of the device, thus overcoming the problems of the cited prior art, such as anomalous displacements or inclinations of the constraint means or of the locking member with respect to the corresponding driving mechanism. The relative positions between the axes Xi and X ₂ remain substantially the same in the various operating conditions of the device.

It should be emphasised that the functions of manual release and compensation referred to may be present, either together or individually, in a device according to the invention, depending upon the production choices, with the major advantage that from one and the same basic structure there may be obtained devices having different functional characteristics (release and compensation; only release; only compensation). For instance, in the production stage, there could be mounted a hook 3 having a shape different from the one illustrated (with the front end more curved or hook-shaped), which, instead of translating following upon a pulling force F ₂ on the door, holds the lock: in this case, the device would hence afford only the function of compensation of the tolerances.

Of course, without prejudice to the principles of the invention, the details of construction and materials and the embodiments may be varied and/or be combined in a way different from what has been described and illustrated so far. Moreover, the individual items described previously may be produced or obtained with any other known technique and may in part be omitted or else be present in a different number and with a different arrangement, or even present different shapes, in order to pursue the aims of the present invention.

As already mentioned, the actuator of the device could be of a type different from the one described previously by way of example, for instance a linear actuator instead of a rotary one, such as a thermo-actuator or an electromagnet.

As has been mentioned, in certain applications, the supporting body of the device may be anchored to the door of the electrical household appliance, and the corresponding retention element may be anchored to the stationary structure, i.e., with an arrangement opposite to the one illustrated in the figures. The position of installation of the device could of course be different from the one exemplified, for example a vertical part of the stationary structure. In certain applications, the locking member 3, the constraint means 4, the retention element 7, and the actuation system 5-6 maybe conceived - according to modalities that will appear clear to the person skilled in the art - in such a way that the member 3 moves angularly about an axis X ₁ that is substantially vertical, instead of being substantially horizontal, as exemplified in the figures.

As mentioned, for the purposes of implementation of the invention, the articulation arrangement that equips the device may have any configuration suitable for enabling angular or rotary movements, as well as combinations of a number of angular or rotary movements, about a single axis or a plurality of axes adjacent to one another. In this perspective, for example, the hinges exemplified with a pin or fulcrum of a substantially cylindrical shape could have a different shape in any case designed for this purpose, such as an articulation at least in part spherical or a restricted or pointed portion.

As an alternative or in addition to the walls 40, the body 2 of the device can define itself one or more constraint and/or guide walls or elements, configured for sliding in a guided way with respect to corresponding seats made in the structure 100 or associated thereto (for example, holes or slits in the structure 100).