Field of the Invention

The present invention relates to an interlock device for the closing door of household appliances, particularly for washing machines and/or tumble dryers.

In household appliances, in particular washing machines and similar appliances, it is mandatory to safely close and lock in the closed position the door for accessing to the charging drum.

The drum is closed by a door with a hermetic seal, hinged to the front panel of the machine and provided with a closing catch that engages with an interlock device, also mounted on the front panel of the machine.

The interlock device also comprises an electromechanical delaying device for instantaneous interlocking and delayed release of the door which has the function of preventing opening of the door after the machine has been started and of delaying opening thereof at the end of the working cycle, for example to ensure that inside it the inertial rotation of the drum has ceased.

Prior art

Door interlock devices are known that also perform the function of preventing starting of the machine with the door open by means of a microswitch that closes the machine operating circuit only when the door is closed and interlocked.

Additionally, known devices, as well as inhibiting starting of the machine with the door open, also make it possible to interrupt its operating cycle in the case that, during operation of the machine, the door catch accidentally becomes detached from its seating, for example as a result of yielding of the catch or of the striking zone or through incorrect dimensioning thereof.

Known devices of this type had the drawback that they permit starting of the machine with the door open in the case that the mechanical device locking the door catch is actuated in the retaining position, for example using a pointed object that simulates the action of the catch.

This drawbacks are solved by the interlock device described in the previous patent application WO201301 1528 in the name of the same Applicant of the present invention, which teaches how to realize an interlock device that provides not only mechanical prevention of starting of the machine with the door open, by effecting, during the operating phase of the machine and in the case of forced opening of the door, opening of the operating circuit with consequent stopping of the operating cycle, but also to recognize if blocking of the closing device occurred incorrectly, without insertion of the door catch.

With reference to Figures 1 , 2 and 3, such kind of interlock device already known in the art comprises a support or containing body 1 , preferably of thermoplastic material, which comprises, in a known way, a portion for fixing to the panel of the washing machine, closed by a cover 2, and a portion for housing a door interlock 3.

The door interlock or delaying device 3 is an electromechanical device, provided in a known manner with a latch 4, actuated by a thermal system, for example by the plate of the moving contact of a microswitch mounted in series on one phase of the machine operating current.

The door interlock 3 is provided with three terminals that extend to the outside in the form of quick-coupling or faston or blade contacts 15, 15', 15" .

One of the contacts 15, called the locked-door contact, has the function of detecting whether the device is in the "door closed" position and locked, and is actuated by a solenoid simultaneously with the interlock latch 4.

A second contact, called the open-door contact, since it has the function of detecting whether the door catch 19 is inserted in the device, is actuated by an actuator 20.

The support 1 is provided with an opening 5, preferably having a rectangular shape, that receives the door catch 19 when the latter is closed.

The mechanical device for locking the door catch 19 consists of a catch or interlock wheel 6, able to rotate to correspond to opening 5 and subject to the action of a torsional spring 17.

Two sliders 7 and 8 are housed in the support 1 and, subject respectively to the action of coil springs 9 and 10, engage the interlock wheel 6 with their shaped ends, 13 and 16 respectively.

The first slider 7, in the central position, is provided with a window 1 1 , for receiving the interlock latch 4 of the electromechanical delaying device 3, and has a shaped notch 12 for actuation of the actuator 20.

The second slider 8 carries, corresponding to notch 12 of the first slider 7, a shaped notch 14 for actuation of the actuator 20.

A further technical problem afflicts the interlock devices of the type described above, and in particular of the type comprising a containing body 1 which in turn comprises a portion for fixing to the panel of the washing machine, closed by a cover, and a portion for housing a door interlock, as per the example of interlock device.

In fact, the cover 2 houses the mechanical device for locking the door catch 19 which comprises the catch or interlock wheel 6, able to rotate to correspond to opening 5, and the torsional spring 17.

A drawback that afflicts the interlock device of the type described above is the disassembly of the cover 2 from the containing body 1 to which the latter is associated. The disassembly of the interlock wheel 6 and/or of the cover 2 from the containing body 1 may therefore occur under different circumstances.

Disassembly of the cover 2 could be caused for example by the hitting of the door catch 19 against the interlock wheel 6 during the closing of the door and when the interlock wheel 6 is in open position.

This could occur for example when door catch 19 dimensions are out of tolerances and/or in every closing procedure when the over rotation of the interlock wheel 6 due to the action of the torsional spring 17 causes a hit against the cover 2 that may cause the disassembly of the cover 2 over lifetime.

Moreover, cover 2 disassembly could be caused by problems related to the interlock wheel 6 dimensions and position which could be out of tolerance, allowing the door catch 19 to slip off the interlock device before the snapping point position of the interlock wheel 19.

Again, cover 2 disassembly may occur when the interlock wheel 6 does not fully rotate to its open position due to some friction with the containing body 1. In this case a little portion of the interlock wheel 6 could face the opening 5 and hit by the door catch 19 when the same is inserted into the opening 5 during the closing of the door.

In view of the above, it has been noted that, irrespective of the reason, during the lifetime of the interlock device the cover 2 may disengage from the containing body 1 causing the loss of the interlock wheel 6, and consequently the impossibility of closing and locking the door.

The disengagement of the cover 2 lead to an additional and more dangerous unwanted situation: when the interlock wheel 6 is not present in its seat due to the uncoupling of the cover 2, the sliders 7 and 8 are free to move subject to the action of springs 9 and 10 respectively.

More in detail, when the door is open and the cover 2 is correctly assembled to the support body 1 , the sliders 7 and 8 are, with their ends 13 and 16 respectively, up against the interlock wheel 6, which is arranged with the concavity facing the opening 5 so that it can receive the door catch 19.

On closing the door, the door catch 19, inserted in the opening 5, causes rotation of the interlock wheel 6 to the closing position and, at the same time, acts upon the shaped end 16 of the second slider 8, which moves to oppose the action of the spring 10.

In this position the second notch 14 releases the actuator 20 and permits its actuation by the first slider 7.

Said first slider 7, under the action of the first spring 9, is pushed to the retaining position of wheel 6 and is positioned with window 1 1 on the same axis as the interlock latch 4 of the door interlock 3, while first notch 12 actuates the actuator 20.

In this configuration the interlock device reveals a situation in which the door is closed and locked, and therefore the machine can be switched on. The door interlock is supplied with current and moves the interlock latch 4 which enters window 1 1 on the first slider 7 locking it in the retaining position of the door catch 19, thus obstructing the rotation of the interlock wheel 6 to the opening position for the entire duration of the operating cycle.

In a normal condition, at the end of the operating cycle the interlock latch 4 moves back releasing the first slider 7 allowing the rotation of the interlock wheel 6 due to the door opening.

From the above description of the functioning of the interlock device according to the prior art it is clear that in case of disassembly of the cover 2 supporting the interlock wheel 6, when the door catch 19 is inserted in the opening 5 it acts upon the shaped end 16 of the second slider 8, which moves to oppose the action of the spring 10. Even in case that the interlock wheel 6 is not in its correct position because of the dismounting of the cover 2, the second notch 14 of the second slider 8 releases the actuator 20 and permits its actuation by the first slider 7.

In fact, even if the interlock wheel 6 is absent due to the dismounting of the cover 2, the first slider 7, under the action of the first spring 9, is pushed towards the area at which the interlock wheel 6 would have been positioned, and the first slider 7 positions its window 1 1 on the same axis as the interlock latch 4 of the door interlock 3, while first notch 12 actuates the actuator 20.

Therefore, even in absence of the interlock wheel 6, the actuator 20 reveals a condition of door closed and locked, the door interlock 3 is supplied with current and moves the interlock latch 4 which enters window 1 1 on the first slider 7 and the machine can be switched on.

This situation is very dangerous and highly unwanted, because the household appliance can be switched on even with the cover 2, and the interlock wheel 6, disassembled from the support body 1 and, therefore, the door is neither retained nor locked in its closed position.

Summary of the invention

The present invention relates to an interlock device for the closing door of household appliances, particularly for washing machines and/or tumble dryers, of the kind suitable to detect closed and locked condition of the door, suitable to solve the problem left unsolved by the prior art.

Particularly, the present invention relates to an interlock device for the closing door of household appliances suitable to solve the problems related to the disassembling of the cover which contains and retains the interlock wheel for retaining the door catch.

More particularly, the present invention relates to an interlock device for the closing door of household appliances suitable to avoid the possibility that the appliance to which it is associated is switched on in case of disassembling of the interlock wheel.

This advantages, and others that will become more clear from the detailed description of a preferred embodiment of the present invention, are achieved by an interlock device according to claim 1.

Further advantages are achieved by the characteristics according to the dependent claims.

Brief description of the drawings

Further details and specific embodiment will refer to the attached drawing, in which:

- Figures from 1 to 3 show an interlock device according to the prior art;

- Figure 4 is a perspective view of the main support body of the interlock device according to the present invention;

- Figure 5 is an perspective view of the second slider of the interlock device according to the present invention;

- Figure 6 is a perspective view of the cover of the interlock wheel of the device according to the present invention;

- Figure 7 is a sectional view of the interlock device according to the present invention in a rest condition in which the door is open;

- Figure 8 is the same sectional view of Figure 7 in a condition in which the door is closed;

- Figure 9 is the same sectional view of Figure 8 in a condition in which the door is locked;

- Figure 10 represents the same operative condition of the interlock device of Figure 9, sectioned with a section plane perpendicular to the section plane of Figure 9;

- Figure 1 1 represents the same section view of Figure 9 in a disassembly of the interlock wheel situation;

- Figure 12 represents the same condition of Figure 1 1 corresponding to a disassembly of the interlock wheel, sectioned with a section plane perpendicular to the section plane of Figure 1 1.

Detailed Description of the Invention

The following description of an exemplary embodiment refers to the accompanying drawings. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various point of the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

With reference to Figures from 4 to 12, the interlock device according to a preferred embodiment of the present invention comprises a support or containing body Γ which comprises a portion for fixing to the panel of the washing machine, closed by a cover 2' , and a portion for housing a door interlock 3' .

The door interlock or delaying device 3' is an electromechanical device, provided in a known manner with an interlock latch 4' , actuated by a thermal system, for example by the plate of the moving contact of a microswitch mounted in series on one phase of the machine operating current.

Even if not explicitly shown in the drawings, the door interlock 3' is provided with three terminals that extend to the outside in the form of quick-coupling or faston or blade contacts.

One of these contacts, called the locked-door contact, has the function of detecting whether the device is in the "door closed" position and locked, and is actuated by a solenoid simultaneously with the interlock latch 4' .

A second contact, called the open-door contact, has the function of detecting whether the door catch 19' is inserted in the device, is actuated by an actuator. The support Γ is provided with an opening 5' , preferably having a rectangular shape, that receives the door catch 19' when the latter is closed.

The mechanical device for locking the door catch 19' consists of a catch or interlock wheel 6' , able to rotate to correspond to opening 5 ' and subject to the action of a torsional spring 17' .

Two sliders are housed in the support Γ and, each subject to the action of a coil spring, engage the interlock wheel 6' with their shaped ends.

In the attached Figures from 4 to 12 is shown only one slider, a first slider 7' , while a second slider having substantially the same function of the second slider 8 of the prior art locking device shown in Figures 1 to 3 is not explicitly shown but is present in the interlock device according to the present invention.

With reference to Figure 5, according to the present invention, the first slider 7' comprises a substantially elongated body 7 'a provided with a window 1 Γ for receiving the interlock latch 4' of the electromechanical interlock or delaying device 3 ' , and has a shaped notch 12' for actuation of the actuator.

The interlock device according to the present invention comprises means for detecting a disassembly condition of the interlock wheel 6' and safety means for preventing the switching on of the household appliance when a disassembly condition of the interlock wheel 6' is detected.

More particularly, safety means for preventing the switching on of the appliance are configured to hamper the closure of the operating circuit of the interlock or delaying device 3' when a disassembly condition of the interlock wheel 6' is detected.

According to a preferred embodiment of the present invention, said means for detecting a disassembly condition of the interlock wheel 6' and safety means are provided on said first slider 7' .

To this purpose, means for hampering the closure of the operating circuit of the interlock or delaying device 3' when a disassembly condition of the interlock wheel 6' is detected comprise, provided on the first slider 7 ' , a locking pin 7'b which projects into the window 1 Γ along the longitudinal direction of the elongated body 7 ' a, the longitudinal direction corresponding to the moving direction of the first slider 7' with respect to the support body Γ .

Means for detecting a disassembly condition of the interlock wheel 6' comprise, on the first slider 7' , a longitudinal groove 7'd from which an arrest element 7'c projects upwardly from the body 7' a in a substantially orthogonal direction with respect to the longitudinal direction of the elongated body 7' .

The operation of the interlock device according to the present invention will be explained here in the following with reference to the preferred embodiment shown in the Figures from 4 to 12.

With reference to Figure 7, when the door is open the first slider 7' subject to the action of the spring 9' , and the second slider not shown in the drawings, are up against the interlock wheel 6' , which is arranged facing the opening 5 ' in a manner suitable to receive the door catch 19' .

The insertion of the door catch 19' in the opening 5' is represented in Figure 10. Once the door catch 19' in inserted in the opening 5' and the interlock wheel 6' rotates, the second slider not shown in the drawings is moved backward against a coil spring and acts on the actuator of the interlock or delaying device 3' revealing the condition of door closed.

The first slider 7' remains in its resting position of Figure 7 in which it obstructs the movement of the interlock latch 4' until the interlock wheel 6' has completed its rotation.

Once the wheel 6' is completely rotated, this condition is represented in Figure 8, the first slider 7 ' moves forward under the action of the coil spring 9' to the retaining position of the interlock wheel 6' , shown in Figures 9 and 10.

The stroke of the first slider 7 ' is limited by the arrest element 7'c which matches against a correspondent part 2' a of the cover 2' , thus detecting the presence of the cover 2' and, consequently, of the interlock wheel 6' .

In this condition, the interlock latch 4' enters the window 1 as visible in Figure 9, closing the operating circuit of the interlock or delaying device 3' , while the notch 12' actuates the actuator and closes the door-locked contact.

Figures 1 1 and 12 show an interlock wheel 6' disassembly condition.

More precisely, the door interlock 6' is supported and partially contained by the cover 2' , which comprises the interlock wheel 6' and the torsional spring 17' , as represented in the Figures, therefore when a disassembly of the cover 2' occurs, the interlock wheel 6' results disassembled too.

When this situation occurs, the first slider' s arrest element 7 'c does not match against the part 2' a of the cover 2' and consequently, under the action of the coil spring 9' , the first slider 7 ' moves forward along the opening 5' area.

The arrest element 7'c is therefore suitable to detect a disassembly condition of the cover 2' .

In this situation, the first slider 7' moves under the action of the spring 9' as represented in Figure 1 1 , and said first slider 7' moves with respect to the body Γ of an extra stroke, until the far internal end 1 1 ' a of the window 1 Γ matches against a corresponding part l ' a of the body Γ .

At the same time, the locking pin 7'b hampers the stroke of the interlock latch 4' and so, even on supplying current to the appliance, the operating circuit of the interlock or delaying device 3 ' cannot be closed because the locked-door contact is open.

It has therefore been shown as the interlock device according to the present invention as described solves the technical problems left unsolved by the prior art. More in details, it has been shown that the interlock device according to the present invention allows to detect a disassembly condition of the interlock wheel 6' and, at the same time, to avoid the switching on of the machine by hampering the closure of the micro-switch 4' revealing the locked-door condition.