EP1640493B1

EP1640493B1 - Door-lock device for a household appliance

Info

Publication number: EP1640493B1
Application number: EP05108596A
Authority: EP
Inventors: Renato Gaj; Marco Moro; Costanzo Gadini
Original assignee: Eltek SpA
Current assignee: Eltek SpA
Priority date: 2004-09-22
Filing date: 2005-09-19
Publication date: 2011-04-06
Anticipated expiration: 2025-09-19
Also published as: EP1640493A2; PL1640493T3; EP1640493A3; DE602005027296D1; ITTO20040636A1

Description

The present invention relates to a door-lock device for a household appliance.
Various types of household appliances are equipped, for reasons of safety, with door-lock devices. For example, washing and/or drying machines, whether of the front-loading type or of the top-loading type, are equipped with a door, through which the user has access to a drum for the normal operations of loading and unloading of the laundry. In these cases, the door-lock device is provided to prevent opening of the door during the cycle of operation of the machine, and, on the other hand, to prevent operation of the machine with the door open. Door-lock devices are typically used also on ovens for cooking equipped with a program or step of pyrolytic self-cleaning, i.e., self-cleaning at a high temperature, to prevent opening of the door of the oven in the course of the aforesaid program, or else to prevent start-up of the program itself in the condition where the door is open or not correctly closed.
In the devices of the type referred to there is, in certain situations, the need to release the door of the household appliance manually, for example in the case of malfunctioning of the actuator that actuates the mechanical part of the device, or else of malfunctioning of the control system that manages said device, or again of a fault in the electrical system of the household appliance.
From the document No. EP-A-0 977 104 there is known a bi-stable actuating system, actuated via a wax electro-thermal actuator, which can be used in combination with a door-lock device for a household appliance. The device described can be released manually, via a purposely provided mechanical system, should the need arise, for example in the case of absence of mains supply or malfunctioning of the control system of the household appliance. Said system comprises a slit formed in the casing of the device, accessible from outside the household appliance, in which the end of a purposely provided implement can be inserted for the purpose of re-setting or modifying the working condition of the device itself, enabling passage thereof into a respective position of release of the door. Albeit reliable, the system referred to in the aforementioned prior document, in addition to requiring the use of a purposely designed implement, is complex from the standpoint of production and use, moreover requiring a particular arrangement of the household appliance that uses it, such as, for example, the presence of a slit that can alter the aesthetic appearance of the household appliance itself.
DE 198 46 863 A1 , upon which the preamble of claim 1 is based, discloses a door lock unit for household devices, having a pawl that co-operates with a door hook and is locked by a control component. The pawl has a pawl body that is moved by the control component and a movable lock that is linked to the pawl body and biased in the lock direction by a spring. The lock can slightly rotates about a pivot pin mounted on the pawl. The lock can also be shifted sideways on the pivot pin, in case manual release of the door lock unit is required, for instance under conditions of electrical power failure.
In its general terms, the present invention is aimed at overcoming one or more of the aforesaid drawbacks, and in particular at providing a door-lock device for a household appliance that is simple and inexpensive to make, as well as being easy to use and service.
The above and other purposes, which will emerge clearly from what follows, are achieved according to the present invention by a door-lock device for a household appliance having the characteristics specified in the annexed claims, which are understood as forming an integral part of the present description.
Further purposes, characteristics and advantages of the present invention will emerge clearly from the ensuing detailed description and from the annexed plate of drawings, which are provided purely by way of explanatory and nonlimiting example and in which:

Figure 1 is a first perspective view of a device according to the invention;
Figure 2 is a side view of the device according to the invention;
Figure 3 is a second perspective view of the device according to the invention, with a respective lid removed;
Figure 4 is a side view of a main body of the device according to the invention;
Figure 5 is an enlarged detail of Figure 4;
Figure 6 is a side view of the device according to the invention, in a first inoperative condition;
Figure 7 is an enlarged detail of Figure 6;
Figure 8 is a cross-sectional view of the device according to the invention, in the condition of Figure 6;
Figure 9 is a side view of the device according to the invention, in an operative condition;
Figure 10 is an enlarged detail of Figure 9;
Figure 11 is a cross-sectional view of the device according to the invention, in the condition of Figure 9;
Figure 12 is a side view of the device according to the invention, in a second inoperative condition;
Figure 13 is an enlarged detail of Figure 12;
Figure 14 is a cross-sectional view of the device according to the invention, in the condition of Figure 12;
Figures 15, 16 and 17 are respectively, a side view, a cross-sectional view, and a perspective view from beneath of a part of a device made according to a possible variant of the invention, in an operative condition similar to that of Figures 9-11;
Figures 18, 19 and 20 are, respectively, a side view, a cross-sectional view, and a perspective view from beneath of the part of the device illustrated in Figures 15-17, in an inoperative condition similar to that of Figures 12-14;
Figures 21, 22 and 23 are, respectively, a first perspective view, a plan view and a second perspective view of a lock member of a device made according to a further variant of the invention; and
Figures 24 and 25 are, respectively, a plan view and a perspective view of a metal plate used for forming of the member illustrated in Figures 21-23.

With particular reference to Figures 1 to 3, the reference number 1 designates as a whole a door-lock device according to the invention, provided for use on a household appliance equipped with a door. For the purposes of the present description, it is assumed that said household appliance is an oven for cooking and that the device 1 is provided for locking the door of the oven in the respective condition of closing when a program of pyrolytic self-cleaning is run.
The device 1 comprises a main body 2, made, for example, of moulded thermoplastic material, designed to be fixed to the cabinet of the oven or in any case to its structure or fixed chassis, the latter being represented only schematically and partially in Figure 2, where it is designated by M. Fixed with known means to the body 2 is an electrical actuator 3; in the case exemplified, the actuator is constituted by a rotary motor, equipped with terminals 3a for the necessary electrical supply.
Associated to the shaft 3b of the motor is an eccentric 4, articulated to which, with means in themselves known, is a slider designated as a whole by 5. The slider 5 is constrained to the body 2 so as to be able to slide linearly between two limit positions, as will emerge from what follows. In this connection, the end wall 2a of the body 2 defines projections for positioning and guiding the slider, some of which designated by 2b in Figure 3.
The end of the slider 5 opposite to the eccentric 4 has a front surface 5a defining an inclined plane designed to co-operate with a movable locking member which, in the case exemplified, is constituted by a catch which can turn through an angle and is designated as a whole by 7, preferably made of metal material. The catch 7 is constrained in a movable way or hinged to the body 2, in particular by means of a pin 8 which extends between two parallel walls 2c of the front portion of the body 2. In the case exemplified, the cylindrical, preferably metal, pin 8 is a component distinct from the body of the catch 7 and inserted in a transverse through hole of the catch itself. In a possible variant, the pin 8 could be formed by two reliefs or protrusions projecting from opposite sides of the body of the catch 7, which are cylindrical and are coaxial with respect to one another. As emerges from Figure 3, a top wall 2d extends between the aforesaid walls 2c of the body 2.
The catch 7 comprises a substantially arched rear portion, designated by 7a in Figure 3, which has an end with a rounded profile and is designed to co-operate with the inclined surface 5a of the catch 7, and a substantially L-shaped or hook-shaped front portion, designated by 7b, the terminal stretch of which is designed to engage in a respective seat 9a, defined in a door of the oven on which the device 1 is mounted. Said door, represented limitedly to the part in which the seat 9a is formed, is designated by 9 in the figures. In the area of joining between its two portions 7a, 7b, the catch 7 is equipped with a transverse through hole, from which there project the ends of the pin 8. It should be noted that, for certain applications, the arrangement could be reversed, i.e., with the body 2 fixed to the door and with the seat 9a, or other retention element designed to co-operate with the catch 7, provided in the fixed or movable structure of the household appliance.
In the case exemplified, the device 1 is further equipped with at least one sensor, such as a microswitch of a normally closed type, designated by 10 in Figure 3, connected or interfaced to the control system of the oven and having a respective sensitive element or feeler 10a, which can be actuated via a corresponding actuation element, such as a shaped rod, designated by 11, constrained to the body 2 so as to be able to slide linearly. For this purpose, defined in the end wall 2a of the body are projections for positioning and guiding the rod 11, some of which are designated by 2e in Figure 3.
The microswitch 10, with the respective rod 11, has the function of detecting whether the door 9 is in the correct closing position, irrespective of the operative condition of the catch 7, in order to issue a command to the control system of the oven for enabling start up a program of pyrolytic self-cleaning. In particular, in the position of correct closing, the door 9 maintains the rod 11 in a retracted position, counteracting the action of a spring 12. In said position, as may be seen, for example, in Figure 3, a projection 11a of the rod 11 is displaced from the feeler 10a in such a way that the microswitch 10 is in a closing condition and thus closes the supply circuit of the motor 3. In said condition, in the case where the user selects the program of pyrolytic self-cleaning, the control system of the oven will supply the motor 3, to enable movement of the slider 5 and hence of the catch 7 so as to bring the latter into the respective operative position, in which it locks the door 9. Instead, in the case where the door 9 is open, or not correctly closed, the rod 11 will be located in an advanced position by virtue of the action of the spring 12, in which position the projection 11a presses the feeler 10a, keeping the microswitch 10 in the opening position, in which it opens the supply circuit of the motor 3. In said condition, the control system of the oven will not enable start-up of the program of pyrolytic self-cleaning even in the case of a specific selection in this sense by the user.
Designated as a whole by 13 is a lid, which is not represented in Figure 3. In the case exemplified, the lid 13 comprises at least one portion 13a, designed to close at the top the area of the body 2 in which the inclined surface 5a of the slider 5 co-operates with the rear portion 7a of the catch 7. As may be seen in Figures 1 and 2, said portion 13a has two symmetrical side projections, one of which designated by 13b, which are designed to extend parallel on the outside of the walls 2c of the body 2, and each have an end designed to be inserted in a respective seat 2f of the body 2. The projections 13b have the function of ensuring correct positioning of the pin 8 in the various conditions of operation of the device 1, as will emerge from what follows.
Illustrated in Figure 4 is just the main body 2 of the device 1, whilst Figure 5 represents a respective enlarged detail thereof corresponding to the area of positioning of the pin 8 of the catch 7, here omitted for reasons of greater clarity. As may be appreciated, present in the visible wall 2c is an opening, designated as a whole by 14, within which there protrudes, in an intermediate position, an elastically deformable wall portion, which forms a sort of arched tooth or elastic element, designated by 15.
Between the tooth 15 and a side edge of the opening 14 (the right-hand edge, in the case of Figure 5) there is delimited a seat, designated as a whole by 16, having an external profile substantially shaped like a figure eight, i.e., with the form of two circular holes that intersect one another in a substantially symmetrical way to form a top portion of seat 16a and a bottom portion of seat 16b. As may be noted, the form of the seat 16 is such that, in the area of intersection of the two aforementioned holes, there is formed a restriction 16c. In an area corresponding to said restriction 16c the width of the seat 16 is smaller than the diameter of the pin 8, whilst the circumference of the latter is substantially coincident with, or slightly smaller than, the circumferential profile of each of the seat portions 16a and 16b.
As may be appreciated, moreover, a part of the profile of the seat 16 (substantially the left-hand part, in Figure 5) is formed in the tooth 15, whilst another part (substantially the right-hand part, in Figure 5) is formed in a substantially rigid portion of the wall 2c. From Figure 5 it is also possible to note how the restriction 16c is formed in part in the elastic tooth 15 and in part in said substantially rigid portion of wall 2c. The portion 14a of the opening 14 that extends from the part of the tooth 15 opposite to the seat 16 (the left-hand part of the opening 14, in Figure 5) enables elastic deformation of the tooth 15, as will emerge from what follows. Finally, in Figures 4 and 5 it is possible to note how the seat 16 is as a whole slightly inclined, with its top portion 16a closer to the part of catch 7b with respect to the bottom portion 16b.
An identical and/or symmetrical passage 14, with corresponding tooth 15 and seat 16, is formed in the wall 2c opposite to the one that may be seen in Figures 4 and 5.
In Figures 6-8, the device 1 according to the invention is represented in an inoperative condition, with the door 9 open. It is to be noted that in said figures, as in Figures 9-11 and 12-14, the lid 13, the rod 11 and some internal components of the device 1, such as the microswitch 10, are not represented for reasons of greater clarity.
In the condition illustrated in Figures 6-8, the pin 8 of the catch 7 extends between the bottom portions 16b of the seats 16 formed in the two walls 2c of the body 2. Note that mounted on the pin 8 is a torsion spring, partially visible in Figures 7, 10 and 13 where it is designated by 17, the terminal branches 17a and 17b of which react, respectively, against the body 2 and the catch 7 in order to bias the latter in its respective inoperative position or position of release. As may be seen in Figure 8, in said step the action of the spring 17 is such that the end of the rear portion 7a of the catch 7 is set resting upon the end wall 2a of the body 2, given the retracted condition of the slider 5. In said inoperative condition of the device 1, opening of the door 9 can be performed by applying thereon a tensile force in the direction of normal opening of the door itself, as indicated by the arrow F in Figure 8.
In the case where the user of the oven selects a program of pyrolytic self-cleaning, the control system enables controlled supply of the motor 3, as previously mentioned with reference to the microswitch 10 and to the rod 11, in order to bring the device 1 into the respective operative condition, or condition of locking of the door 9 in the closed position.
The motor 3 is controlled in such a way that its shaft 3b determines an angular movement through 180° of the eccentric 4, with the consequent advance of the slider 5 (towards the right, as viewed in Figure 11). As may be seen in Figure 11, following upon advance of the slider 5, its inclined front surface 5a can penetrate underneath the rounded end of the rear portion 7a of the catch 7. In this way, the catch 7 is induced to move angularly about the pin 8, countering the action of the spring 17. At the end of said angular movement, the end of the portion 7a of the catch 7 comes to rest upon the top surface of the slider 5.
Basically, the aforesaid angular movement of the catch 7 is such that the rear portion 7a rises, with consequent lowering of the front portion 7b of the catch itself. The end of said front portion 7b then penetrates within the seat 9a of the door 9, blocking the latter in the closing condition. In said condition, as represented in Figures 9-11, a normal tensile force exerted on the door 9 does not enable opening of the latter.
The operative condition illustrated in Figures 9-11 is maintained throughout the cycle of pyrolytic self-cleaning. At the end of said cycle, the control system of the oven determines a new activation of the motor 3 in order to bring about a new angular movement through approximately 180° of the eccentric 4. As a result, recession of the slider 5 is obtained, followed by the return of the catch 7 into the position indicated in Figures 6-8, by virtue of the action of the spring 17. The device 1 then returns into the respective inoperative position, in which the door 9 can be freely opened by the user.
In conditions of normal operation, in the passage from the condition of door open and released illustrated in Figures 6-8 to the condition of door closed and locked illustrated in Figures 9-11, the pin 8 is always positioned in the bottom portion 16b of the seat 16, as may be seen for example in Figures 6 and 9.
Assume now that the device 1 is set in the operative condition illustrated in Figures 9-11, i.e., with the door 9 blocked in the closed position via the catch 7. In said situation, if for any reason whatsoever (such as, for example, a malfunctioning of the control system or a mains supply black-out) the motor 3 is not in the condition of being made to work in the way described above, the release of the device 1 can be obtained manually by virtue of the particular construction of the seat 16 of the pin 8.
For this purpose, a tensile force must be exerted on the door 9, i.e., a force must be applied in the direction of normal opening of the door itself, as indicated schematically by the arrow F' of Figure 11. Note that the device 1 is conceived such that the force F' necessary for obtaining manual release of the device to be considerably greater than the force F required for opening the door 9 in conditions of normal use, i.e., a force such as to meet the safety standards; merely by way of example, for this purpose a tensile force F' of at least 20 kg must be applied to the door 9.
The arrangement between the catch 7 and the seat 9a is such that the torque exerted on the door 9 determines a vertical component of force on the catch itself, with the end 7b of the latter that will tend to move angularly in a counterclockwise direction, as viewed in the figures, or upwards. Preferably, at least some surfaces that co-operate with one another of the end of the portion 7b of the catch 7 and of the seat 9a of the door 9 will be in the form of slightly inclined planes, for the purpose of obtaining the components or forces necessary for the movement of release of the catch 7.
As has been said, in the situation under examination (device 1 that blocks the door - Figure 11), the portion 7a of the catch 7 is resting upon the top surface of the slider 5. Consequently, following upon the aforesaid vertical component of force that is applied on the portion 7a (approximately 4 kg, with reference to the aforementioned example of tensile torque F' of approximately 20 kg), the catch 7 tends to behave, as a whole, as a second-class lever, with the point of rest of its portion 7a on the slider 5 that functions as fulcrum.
The pin 8 is then biased upwards within its end seats 16, i.e., pushed against the restriction 16c. Note that, in said step, the angular movement of the catch 7 is limited by the interference between an intermediate area of its portion 7a with the top wall 2d of the body 2, as may be seen in Figure 14. This fact, together with the inclination of the seat 16, entails the consequence that the force exerted on the pin 8 is unloaded on the teeth 15.
In this way, the teeth 15 are induced to undergo elastic deformation, towards the portion 14a of the respective passage 14, thus causing an increase in the width of the seat 16 in an area corresponding to the restriction 16c, such as to enable the pin 8 to pass from the bottom portions of seat 16b to the top portions of seat 16a, displacing upwards also the spring 17. In this way, there is obtained a snap-action passage of the pin 8 from the seat portions 16b to the seat portions 16a, and when said position is reached, the tooth 15 will return elastically into the original position, as may be seen, for example, in Figure 13.
Following upon said displacement of the pin 8, also the front portion 7b of the catch 7 will be displaced upwards, and its end will exit from within the seat 9a of the door 9, as may be seen in Figures 12 and 14, thus releasing the latter, which may be opened.
As may be appreciated, the opening 14, or more in particular the tooth 15 and the seat 16, provide bistable switching means, which can be actuated to bring about translation of the pin 8, and hence of the catch 7, between a position of normal operation and a position of special operation, both being stable. In the position of normal operation, the actuating system formed by the electrical actuator 3, the eccentric 4 and the slider 5 thus enables the catch 7 to be brought from a first inoperative condition (Figures 6-8) to an operative condition (Figures 9-11), whereas, in the position of special operation, the catch 7 assumes a second inoperative condition, in which the catch itself is not engaged with the retention element constituted by the seat 9a. Actuation of the aforesaid switching means, which is necessary to bring about said translation from the position of normal operation to the position of special operation, can be obtained by applying on the door, in its normal direction of opening, a force that is considerably greater than the minimum force necessary for opening the door itself when the catch is set in said first inoperative condition illustrated in Figures 6-8.
The device 1 can then be restored manually by a person responsible for carrying out technical assistance on the oven, by first pushing the front portion 7b of the catch 7 downwards. In said step (as may be seen in Figure 14 in relation to the position of the catch 7 alone), an intermediate stretch of the portion 7a of the catch is in contact with the top wall 2d of the body 2. For said reason, the catch 7 behaves again as a second-class lever, with the point of rest of the aforesaid intermediate stretch of the portion 7a on the top wall 2d that functions as fulcrum.
The force applied manually in this way on the catch 7 causes the pin 8 to be biased downwards within the seats 16, i.e., pushed against the respective restricted areas 16c. The teeth 15 are then again induced to undergo elastic deformation, towards the portion 14a of the respective passage 14, thus causing an increase in the size of the restriction such as to enable the pin 8 to pass from the top portions of seat 16a to the bottom portions of seat 16b, displacing downwards also the spring 17. There is thus obtained snap-action switching of the pin 8 from the seat portions 16a to the seat portions 16b, with the subsequent return of the teeth 15 into their original position, as may be seen, for example, in Figures 9 and 11 limitedly to the position of the catch 7 (the door 9 will now be in the opening condition). Next, the slider 5 must be brought into the respective retracted position, for example by rotating the eccentric 4 so that the system will return into the position that may be seen in Figures 6 and 9.
As previously mentioned, the projections 13b of the lid 13 illustrated in Figures 1 and 3, when coupled in the respective seats 2f of the body 2, are each set up against a wall 2c, in an area corresponding to the respective seat 16. In this way, the projections 13b perform the function of guaranteeing correct position of the pin 8 in its various possible operating conditions, and in particular in the course of passage between the seat portions 16a and 16b, thus preventing them from sliding out of the seat 16 or from being misaligned or inclined.
From the foregoing description, it may be appreciated how the device 1 according to the invention is simple and inexpensive to produce. It is pointed out in particular that the system that enables manual release of the device is in effect obtained through the particular conformation of the passages 14, and hence of the teeth 15 and of the seat 16, elements that are defined in the course of the operation of moulding of the body 2 made of thermoplastic material.
Manual release of the device does not render necessary the use of specific implements and can be achieved in an extremely convenient way, possibly directly by the user of the household appliance, whenever the need arises. Also the subsequent step of restoring functionality of the device 1 is obtained via operations which are in themselves elementary and which do not normally involve replacement of components of the mechanical mechanism.
Of course, without prejudice to the principles of the invention, the details and materials of construction and the embodiments may vary with respect to what is described and illustrated herein. Without departing from the scope of the appended claims.
In particular, it is pointed out that the actuator of the device 1 could be of a type different from the one described previously by way of example. In this perspective, the actuator 3 could also be constituted by a linear actuator. The actuator could be of an electromagnetic type, or else of a thermal or electro-thermal type, for example with operation based upon the use of a material designed to expand and/or contract (such as a wax), or other monostable actuator, or again a bistable actuator, i.e., one able to vary its own operative condition between a stable resting position and a stable working position, according to the presence or otherwise of supply. In the case where a monostable actuator is used, a bistable mechanism of a known type could be associated thereto, for example as described in EP-A-0 663 633 .
The pin 8 and the opening 14 could present a reversed arrangement with respect to the one previously exemplified. In this perspective, the body of the catch 7 could, for example, comprise at least one passage or a transverse slot, shaped to provide the tooth 15 and the seat 16, whilst the axis of rotation could extend between the two walls 2c, or else be constituted by two coaxial cylindrical protrusions, each projecting from a wall 2c.
Represented schematically in Figures 15-20 is a possible variant in this sense, in which the device according to the invention is illustrated limitedly to its front part, in which there is positioned the catch 7. In said figures, the same reference numbers are used as in the previous figures to indicate elements that are technically equivalent to the ones already described previously.
In the case of the variant in question, the pin 8 extends between two coaxial holes provided in the two walls 2c of the body 2, in a substantially fixed position (except for the possibility of the pin 8 of rotating about its own axis). In this case, the catch, designated as a whole by 7', has a central undercut, obtained for example by removal of material, in such a way that there are formed in its body two thin walls that are parallel to one another, designated by 7c in Figures 17 and 20, which also define at least the front portion 7b of the catch itself. In each wall 7c, a portion 14' is formed, which, in the case exemplified, comprises a slot with a profile which is substantially similar to that of the opening previously designated by 14, and which consequently has a respective deformable tooth 15 and a seat divided into two portions 16a and 16b. The walls 7c are sufficiently thin to enable the necessary elastic bending of the teeth 15, for the purposes described previously, and the portions 14' of the two walls 7c are in positions substantially specular with respect to one another.
In addition, in the case of the variant in question, also the coupling positions between the pin 8 and the portions of seat 16a, 16b are reversed with respect to the main embodiment described previously. This means that, in the position of normal operation, the bottom portions of seat 16b will be engaged on the pin 8, whereas, in the position of special operation, the top portions of seat 16a will be engaged on the pin 8.
In Figures 15-17, the device 1 may in fact be seen in its position of normal operation, in the condition of locking of the door (not represented therein). In said condition, as may be noted in particular in Figure 16, the top portions of seat 16a of the catch 7' are engaged on the pin 8. In the course of normal operation, as described previously, following upon recession of the slider 5, the catch 7' may be brought angularly into the respective first inoperative condition, in which the catch itself releases the door. Also in this variant, if need be, the door-lock device can be brought into the respective position of special operation, by applying on the door a sufficiently high tensile force, with the modalities described previously. In this way, bending of the teeth 15 is obtained with the translation of the catch 7', enabled by the fact that the portions of seat 16b will engage on the pin 8 instead of the portions of seat 16a, as may be seen in Figures 18-20.
Normally, the catches used in door-lock devices for household appliances have a full body; for example, this is the case of the embodiment illustrated in Figures 1-14. Also in the variant illustrated in Figures 15-20, the body of the catch 7' is prevalently full, even though it has a central undercut aimed at enabling formation of the two parallel walls 7c, in which the shaped passages 14' for the pin 8 are formed.
According to a variant of the invention, the embodiment of a catch for a door-lock device having non-full body is proposed, i.e., with a substantially box-shaped structure. Said possibility is illustrated schematically in Figures 21-25.
With particular reference to Figures 21-23, designated as a whole by 7" is a locking device or catch suitable for application in a door-lock device for household appliances, the body of which is obtained from a plane metal plate 20, shaped in order to obtain a particular perimetral profile and then bent substantially to form a U so as to obtain two parallel side walls 7c, joined to one another by a common or top wall 7d.
As may be noted, the opposite ends of the parallel walls 7c are shaped so as to form the rear portion 7a and front portion 7b of the catch itself, which are here each constituted by parallel terminal stretches of the same walls 7c. As may be appreciated, in the case of the rear portion 7a of the catch, the terminal stretches of wall 7c have the rounded profile necessary to enable co-operation with the slider 5. As regards the front portion 7b of the catch, the respective terminal stretches of wall 7c are provided with at least one inclined-plane stretch, suitable for co-operating with a surface of the seat 9a of the door 9 described previously, in order to obtain the components or forces necessary for movement of switching of the device.
In the embodiment illustrated in Figures 1-14, the catch of the device 1 basically has two arms set at angles with respect to one another, which form their respective portions 7a and 7b. In the case of the variant illustrated in Figures 21-23, instead, the two portions 7a and 7b are, in effect, made just by the end of the side walls 7c, and hence the top surface of the catch 7", represented by the wall 7d, can be substantially plane. This enables the two side walls 7c to be obtained in a convenient way, via simple operations of bending of the plate 20. Obviously, there could advantageously be obtained more complex forms of the catch 7" with further or different shapes and/or bends. As may moreover be seen, formed in each wall 7c is, in an intermediate position, a respective portion 14', with a passage or a slot having a profile substantially similar to that of the opening previously designated by 14, and hence provided with a respective deformable tooth 15 and a seat divided into two portions 16a and 16b. As may be appreciated, then, the modalities of use and operation of the catch illustrated in Figures 21-23 are substantially similar to those described with reference to the variant of Figures 15-20.
In Figures 24 and 25, there may be seen a plate 20 which can be used for formation of the catch 7", in a plane configuration. Said plate 20 is obtained from a metal sheet or strap, so as to have a peripheral profile conformed to provide the various functional parts of the catch 7", and in particular the portions 7a, 7b and the passages or slots 14' that delimit the respective tooth 15 and seat 16. The aforesaid complex profile of the plate 20 can be obtained via shearing, chemical etching, milling, laser cutting, or any other known technique designed for the purpose.
In the course of formation of the aforesaid profile, on the plate 20 there are preferably formed, with known modalities, also at least two reductions of thickness or longitudinal incisions, preferably but not necessarily parallel, represented schematically by the dashed straight lines in Figures 24 and 25, aimed at forming preferential lines of bending for the plate itself. As may be appreciated, said incisions delimit within the plate 20, which is still in a plane configuration, the areas designed to form the walls 7c and 7d.
After obtaining the plate 20, as may be seen in said Figures 24 and 25, this is bent substantially to form a U, exploiting the presence of the aforesaid incisions, and in particular bending the areas of plate which are to form the side walls 7c orthogonally with respect to the area of plate which is to form the top wall 7d. Following upon said bending operation to form a U, the catch 7" is then formed and ready for use.
The aforesaid process enables the catch 7" to be obtained in an extremely simple and inexpensive way, via operations that are easily automatable, and with less material than for a catch with a full body.
The use of the catch 7" according to the embodiment of Figures 21-23 can involve slight modifications in the geometry of the body 2 of the device 1 described previously. It is pointed out, for example, that the top wall 2d could be in a position slightly retracted with respect to what has been illustrated previously, in order to enable the catch 7" to make the necessary movements.
Finally, it should be emphasized how the technique of construction of the catch 7" starting from metal plate can advantageously be used also in the case of the embodiment of the invention illustrated in Figures 1-14. Of course, for this case the side walls 7c of the catch will not be provided with the respective shaped portion 14', but with a simple through hole for passage of the necessary pin for articulation of the catch.

Claims

A door-lock device for a household appliance of the type having a structure (M) to which a door is associated (9), the device (1) comprising:
- a movable locking member (7; 7'; 7"), mounted via constraint means (8) on a main body (2), where the main body (2) is to be rendered fixed to one of said structure (M) and said door (9), and the locking member (7; 7'; 7") is designed to co-operate with at least one retention element (9a) of the other of said structure (M) and said door (9), the locking member (7; 7'; 7") being angularly movable about a respective axis,

- an actuating system (3-5) having actuator means (3) designed to determine passage of the locking member (7; 7'; 7") between:
- a first inoperative condition, in which the locking member (7; 7'; 7") is not engaged with said retention element (9a), so as to enable opening of the door (9) by applying a first force (F) thereon in a direction of normal opening, and

- an operative condition, in which the locking member (7; 7'; 7") is engaged with said retention element (9a) so as to keep the door (9) in a respective closed position even when said first force (F) is applied in said direction of normal opening,

said device (1) further comprising switching means (14-16; 14'-16) operative for enabling translation of said locking member (7; 7'; 7") from a position of normal operation to a position of special operation in which the locking member (7; 7'; 7") is not engaged with said retention element (9a), said position of normal operation being restorable,
characterized in that said switching means (14-16; 14'-16) are operative for enabling translation of said locking member (7; 7'; 7") from said position of normal operation to said position of special operation following upon application on the door (9), in said direction of normal opening, of a second force (F') greater than said first force (F).
The device according to Claim 1, characterized in that said second force (F') is considerably greater than the minimum force necessary for opening the door (9) when the locking member (7; 7'; 7") is in said first inoperative condition.
The device according to Claim 1, characterized in that said switching means (14-16) are operative for enabling, following upon application on the door of said second force (F'), also the translation of said constraint means (8) between a first position and a second position, which correspond, respectively, to said position of normal operation and said position of special operation of the locking member, where in particular:
- in the first position of said constraint means (8), the movement of the locking member (7; 7'; 7") between said operative condition and said first inoperative condition is determined by said actuating system (3-5), via control of said actuator means (3), and

- in the second position of said constraint means (8), the locking member (7; 7'; 7") assumes a second inoperative condition, in which the member itself is not engaged with said retention element (9a).
The device according to Claim 1 or Claim 2, characterized in that said switching means (14-16; 14'-16) are substantially of a snap-action type or bistable type.
The device according to Claim 1, characterized in that said axis is translatable between a first position and a second position, which correspond, respectively, to said position of normal operation and said position of special operation.
The device according to Claim 1, characterized in that said locking member (7; 7'; 7") is able to operate as a second-class lever with a fulcrum different from said axis, for the purpose of passing between said position of normal operation and said position of special operation.
The device according to Claim 3, characterized in that said locking member (7; 7'; 7") is able to operate as a second-class lever with a fulcrum different from said axis, for the purpose of passage of said constraint means (8) between the respective first position and second position.
The device according to Claim 1, characterized in that said constraint means comprise pin means (8) having at least one respective portion projecting from said locking member (7), and in that said switching means (14-16) comprise at least one passage or one slot (14) formed in a respective wall (2c) of said body (2), within which said projecting portion is at least in part inserted.
The device according to Claim 1, characterized in that said constraint means comprise at least one of:
- pin means (8) fixed to and/or projecting from at least one respective wall (2c) of said body (2), and

- pin means (8) that extend between two walls (2c) of said body (2),
and in that said switching means comprise at least one passage or one slot (14') formed in said locking member (7'; 7"), within which said pin means (8) are at least in part inserted.
The device according to Claim 5 or 6, characterized in that
- said axis is formed by pin means (8) projecting from two opposite sides of said locking member (7) and said switching means (14-16) comprise a first passage or slot and a second passage or slot (14), each formed in a respective wall (2c) of said body (2), a respective portion of said pin means (8) being inserted within each passage or slot (14), or

- said axis is formed by pin means (8) that extend between two walls (2c) of said body (2), and said switching means (14'-16) comprise at least one passage or slot (14') formed in a respective wall (7c) of said locking member (7'; 7"), a respective portion of said pin means (8) being inserted within each passage or slot (14').
The device according to any one of Claims 8 to 10, characterized in that
- into said passage or slot (14; 14') there protrudes an element or tooth (15), which is flexible or elastically deformable and forms part of said switching means (14-16; 14'-16), and/or

- said passage or slot (14; 14') defines an at least in part elastically deformable seat (16), within which a respective portion of said pin means (8) is inserted, and/or

- said passage or slot (14; 14') defines a seat (16) having a first portion of seat (16a) and a second portion of seat (16b) between which a restriction (16c) is present, each portion of seat (16a, 16b) being able to house a respective portion of said pin means (8), said seat (16) forming part of said switching means (14-16; 14'-16).
The device according to Claim 11, characterized in that said seat (16) has the form of two circular holes that intersect one another, to form said first portion of seat (16a) and said second portion of seat (16b), a restriction (16c) being formed in the area of intersection of said holes, where in particular, in an area corresponding to said restriction (16c), the width of the seat (16) is smaller than the diameter of said pin means (8), and the circumference of said pin means (8) is substantially coincident with, or slightly smaller than, the circumferential profile of each of said holes.
The device according to Claims 11 or 12, characterized in that said seat (16) is delimited at least in part between said elastic element or tooth (15) and a substantially undeformable edge of said passage (14; 14'), where in particular, in the course of the passage of said locking member (7; 7'; 7"):
- between said position of normal operation and said position of special operation, and/or

- from said operative position to said second inoperative position, and/or

- from said second inoperative position to said first inoperative position,
said pin means (8) are operative for exerting a thrust on said elastic element or tooth (15), determining a bending or elastic deformation or displacement thereof, and hence an increase in the width of said seat (16) in an area corresponding to said restriction (16c), in such a way that said pin means (8) is able to pass from one portion of seat (16a, 16b) to the other.
The device according to Claim 1, characterized in that said switching means (14-16; 14'-16) can be actuated by exerting a force directly on said locking member (7; 7'; 7").
The device according to Claim 14, characterized in that said switching means (14-16; 14'-16) can be actuated manually, in particular when the locking member (7; 7'; 7") is in said second inoperative condition, to cause a translation of said constraint means (8) and hence passage of the locking member (7; 7'; 7") from the position of special operation to the position of normal operation.
The device according to Claim 1, characterized in that said actuating system (3-5) comprises at least one slider (5) constrained to the fixed structure (2) so as to be able to slide linearly between two limit positions, following upon an actuation of said actuator means (3), where in particular said slider (5) comprises an end defining an inclined plane (5a) that is able to co-operate with said locking member (7; 7'; 7").
The device according to Claim 1, characterized in that said locking member (7; 7'; 7") is constituted by a catch that is angularly movable and having:
- a rear portion (7a) with an end that has a rounded profile and is designed to co-operate with an inclined surface (5a) of a slider (5) forming part of said actuating system (3-5), and

- a front portion (7b) having a terminal stretch that is able to engage with said retention element (9a).
The device according to Claim 1, characterized in that it comprises elastic means (17) for constantly biasing said locking member (7) in the direction of said first inoperative condition, where in particular, both in said operative condition and in said second inoperative condition, the rear portion (7a) of the locking member (7; 7'; 7") locally rests upon a top surface of the slider (5), whilst in said inoperative condition it locally rests upon a first wall (2a) of said body (2).
The device according to Claim 1, characterized in that associated to said body (2) is a lid (13) having portions (13b) operative for guaranteeing maintenance of a correct working position of said constraint means (8).
The device according to Claim 1, characterized in that said actuator means (3) comprise at least one from among a rotary or angular actuator, a linear actuator, a bistable actuator, a monostable actuator operatively associated to which is a bistable mechanism, an electrical actuator, a thermal actuator, an electromagnetic actuator, an electro-thermal actuator.
The device according to Claim 1, characterized in that said locking member (7; 7'; 7") and said retention element (9a) have co-operating surfaces at least in part shaped like an inclined plane.
The device according to at least one of the preceding claims, characterized in that said locking member (7'; 7") comprises two substantially parallel walls (7c), in which there are at least in part formed said switching means (14'-16).
The device according to at least one of the preceding claims, characterized in that said locking member (7") comprises a respective body obtained from a metal plate or strap (20) that is at least in part bent.
The device according to Claim 23, characterized in that said plate (20)
- comprises at least two portions that are bent with respect to one another (7c, 7d), preferably in an orthogonal way, and/or

- comprises at least three portions that are bent with respect to one another (7c, 7d), of which two side portions (7c) and a central portion (7d), the side portions (7c) being substantially parallel to one another, and/or

- is bent substantially to form a U, in such a way that said locking member (8) comprises at least two walls (7c) substantially parallel to one another, formed by said side portions of said plate (20), where in particular in said walls (7c) of the locking member (7") there are at least in part formed said switching means (14'-16), and/or

- has at least two stretches of complex peripheral profile (14'), or else two through openings, made in a specular way in two opposite areas of the plate itself, where in particular said stretches of complex peripheral profile (14'), or else said through openings, are parallel to one another or lie on parallel planes following upon bending of the plate (20), and/or

- integrates at least part of said switching means (14'-16).