Motorized hinge

A hinge (1) for connecting a door to a household appliance compartment is described, comprising a fastening bracket (2) adapted to be fastened to the compartment of said household appliance, a movable support (3) to rotatably constrain said door to said fastening bracket (2), an activating arm (5) coupled to said fastening bracket (2), movement means (6) adapted to move said activating arm (5), said activating arm (5) comprising a first end portion (5a) adapted to be constrained to said door, and a second end portion (5b) fitted to be coupled to said movement means (6) to move said activating arm (5) between an open position (P2) of the door and a closed position (P1) of the door, said movement means (6) comprising an electric motor (10) and reversible connecting means (9) to couple and decouple selectively said electric motor (10) and said second end portion (5b), said hinge (1) being configured so that when said electric motor (10) is coupled to said second end portion (5b), the electric motor (10) causes the movement of the activating arm (5), whereas when said electric motor (10) is decoupled from said second end portion (5b), the movement of the first end portion (5a) occurs independently of the electric motor (10) to allow a user to freely move the door.

This Non-Provisional application claims priority to and the benefit of Italian Application No. 202019000002526 filed on 24 Jul. 2019, the content of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the field of hinges. The invention is mainly intended for the field of hinges made for connecting a door to a household appliance compartment, such as, for example, for connecting a door to an oven compartment. It should be noted that hereinafter, the term “household appliance” will generally refer to a household appliance or machinery of the type prevalently driven by electric current or gas, such as, for example, a refrigerator, dishwasher, oven, washing machine, etc.

Known Prior Art

In the known art, hinges used to connect a door to a household appliance compartment are known, such as, for example, the compartment of an oven, dishwasher and the like.

These hinges typically comprise a fastening bracket adapted to be fastened to the household appliance compartment and a movable support to rotatably constrain the door to such bracket. In particular, the movable support of the hinge, fastened to the door, is pivoted to the fastening bracket so that the door is rotatable around a rotation axis (e.g. horizontal or vertical) between an open position and a closed position.

Known hinges can also be provided with elastic means for leading the door towards the closed position. For example, in case of ovens, the elastic means can be coupled to an activating arm comprising a first end portion constrained to the door or better to the respective movable support, and a second end portion coupled to the fastening bracket. The elastic means can, for example, act on the first end portion, so as to move the door towards the closed position.

In order to facilitate the opening of the door, known hinges are provided with a motor drive, typically electrical, and are adapted to perform the opening/closing functions of the door. These hinges, for example, can be provided with a manual user control that, once actuated, turns on an electric motor to open or close the door. The electric motor, acting directly on the hinge of the door, is normally sized to fully move the door autonomously between the open position and the closed position.

In particular, in order to allow the door to move from the closed position to the open position, by counteracting the force exerted by the elastic means, the motor used on known hinges can be bulky and expensive, in addition to consuming a high amount of electric energy.

Known motorized w3edszhinges may also have difficulties in opening and closing the door (not fluid or tiring for the user) in case of motor malfunctions or in the absence of electric current. In certain cases, known motorized hinges could remain locked in the absence of electric current. This problem is particularly annoying when motorized hinges are installed on an oven. In this case, any absence of electric energy while cooking food, or even the malfunctioning of the motor of the hinge, could hamper the opening of the oven door, therefore resulting in a consequent excessive cooking time (also due to, for example, the oven's thermal inertia), which could ruin or burn the food inside of the oven itself.

SUMMARY OF THE INVENTION

Object of the present invention is to solve the aforesaid problems and to provide a hinge for connecting a door to a household appliance compartment able to be motorized, while simultaneously allowing a user to freely move the door when the door is stationary.

Another further object of the present invention is to provide a hinge able to be motorized by using an electric motor of reduced size and with reduced electric consumptions.

These and further objects are achieved by the present invention thanks to a hinge and to a household appliance according to the independent claims. Preferred aspects are set forth in the dependent claims.

In particular, according to an aspect of the present invention, the hinge for connecting a door to a household appliance compartment comprises a fastening bracket adapted to be fastened to the compartment of the household appliance and a movable support to rotatably constrain the door to the fastening bracket around a rotation axis.

The hinge further comprises an activating arm coupled to the fastening bracket, movement means adapted to move the activating arm, and elastic countering means functionally interposed between the fastening bracket and the activating arm.

The activating arm comprises a first end portion adapted to be constrained to the movable support of the door and a second end portion adapted to be coupled to the movement means intended to move the activating arm between an open position of the door and a closed position of the door.

According to an aspect of the present invention, the elastic countering means are functionally interposed so that to provide an elastic countering force adapted to lead the activating arm towards the closed position and/or towards the open position of door.

According to an advantageous aspect of the present invention, the movement means comprise an electric motor and reversible connecting means to couple and decouple selectively the electric motor and the activating arm, and, in particular, these means allow the direct or indirect coupling or decoupling of the drive shaft of such electric motor and the aforesaid second end portion of the activating arm.

The hinge is configured so as to ensure that, when the electric motor is coupled to the second end portion of the activating arm, the electric motor causes the movement of the activating arm, in particular it pushes or pulls the movable support of the door to make it rotate, while, when the electric motor is decoupled from the second end portion, the manual movement of the first end portion of the activating arm occurs independently of the electric motor (i.e. without operating on the motor) to allow a user to freely move the door.

This way, the second end portion of the activating arm can only be coupled to the electric motor when a door movement is required, a movement that is physically carried out by suitable movement means.

Preferably, the movement means comprise a slider linearly moved, by means of a screw for example, by means of the electric motor. The slider is constrained to the second end portion of the activating arm.

In particular, according to an aspect of the present invention, the second end portion of the activating arm is preferably constrained to the slider so that to be moved along a direction parallel to the movement of the slider.

Preferably, the first end portion and the second end portion of the activating arm are rotatably constrained to each other at an intermediate portion of the activating arm, for example by means of a pin arranged perpendicularly to the moving direction of the slider. More preferably, the first and the second end portions of the activating arm are rotatably constrained to each other around a rotation axis substantially parallel to the rotation axis of the support movable with respect to the fastening bracket. Further embodiments can however provide that the activating arm consists of a single piece (i.e. that the first end portion and the second end portion of the activating arm are integral with each other), still remaining within the protection scope of the present invention.

Some embodiments can provide that the electric motor is a magnetic linear motor, alternatively, as already mentioned, the movement means comprise a reversible screw adapted to be rotated by means of the electric motor (e.g. a direct-current electric motor). The slider is therefore coupled to the screw, preferably by means of a screw-nut screw coupling so as to transform the rotation of the screw into a translation of the slider. In this embodiment, the reversible connecting means are configured to couple and decouple selectively the electric motor and the screw.

Preferably, the activating arm is subjected to an elastic countering force adapted to lead this activating arm towards the closed position of the door. The aforesaid elastic countering force is provided by elastic countering means functionally interposed between the fastening bracket and the activating arm.

Some embodiments can provide that the elastic countering means comprise at least one spring functionally interposed between the second end portion of the activating arm and the fastening bracket. Alternatively or in addition, the elastic countering means preferably comprise a spring functionally interposed between the fastening bracket and an intermediate portion of the activating arm, comprised between the first and the second end portion.

According to an aspect of the present invention, the reversible connecting means comprise a joint of the coupling type, by means of complementary toothing for example, provided with a first member constrained to a driven member kinematically coupled to the activating arm, such as a screw for example, and a second member constrained to the drive shaft of the electric motor. The second member is movable with respect to the first member and/or vice-versa between a configuration of mutual engagement, wherein the rotation of the drive shaft of the electric motor is transferred to the activating arm, such as by means of the screw for example, and a configuration of mutual disengagement, wherein the activating arm and member to which it can be constrained, such as a screw, are free to move independently of the rotation of the drive shaft of the electric motor.

Advantageously, the reversible connecting means comprise elastic means configured to lead the second member and/or first member of the coupling joint to the configuration of mutual disengagement.

Preferably, the reversible connecting means comprise an electromagnet (or any electromechanical actuator known in the art) to lead the second member and/or first member of the coupling joint to the configuration of mutual disengagement.

According to a further aspect of the present invention, the reversible connecting means are configured to couple the electric motor to the activating arm and, in particular, to the second end portion of the activating arm, in response to a user actuation command.

Preferably, the hinge comprises means for detecting the electric current absorption of the electric motor. The position taken by the door during the movement between the open and closed positions preferably causes a variation in the electric current absorption of the electric motor and, since it is easily detectable, it can be advantageously used to obtain the position of the activating arm.

According to an aspect of the present invention, the movement means preferably comprise a connecting bracket configured to rotatably constrain the electric motor to the household appliance compartment.

A further object of the present invention is a household appliance comprising at least one hinge according to any one embodiment the present invention.

EMBODIMENTS OF THE INVENTION

FIGS. 1A and 1Bshow a particular embodiment of the hinge1according to the present invention for connecting a door to a household appliance compartment. In particular,FIG. 1Ashows the hinge1when the door is in a closed position P1, andFIG. 1Bshows the hinge1when the door is in an open position P2.

The hinge1comprises a fastening bracket2adapted to be fastened to the compartment of the household appliance, for example by means of screws or other known fastening means. The door is configured to be rotatably constrained to the fastening bracket2by means of a movable support3. This movable support3, which can consist of an additional bracket, is stably fastened to the door, inside of a housing arranged inside the door itself for example, and is rotatably constrained to the fastening bracket2, such as by means of a pin4, so that the door can rotate around a rotation axis R-R (e.g. a horizontal axis) with respect to the fastening bracket2.

In the embodiment herein shown, the movable support3is pivoted to the fastening bracket2so that when the movable support3is fastened to a respective door, the door is rotatably constrained to the fastening bracket2around a horizontal axis R-R.

Further embodiments can however provide that the movable support3is shaped variously and made integral with the door in ways per se known to the art, in addition to being pivoted to the fastening bracket2in various modes, still remaining within the scope of protection of the present invention.

The hinge1further comprises an activating arm5that can be coupled to the fastening bracket2and that is constrained to the movable support3, or directly to the door, and movement means6adapted to move the activating arm5between an open position of the door P2(shown by way of example inFIG. 1B) and a closed position of the door P1(shown by way of example inFIG. 1A). In particular, the activating arm5comprises a first portion5arotatably constrained to the movable support3(e.g. by means of pins8) and a second portion5badapted to be coupled to the movement means6. The movement means6act on the second portion5bof the activating arm5so as to move the activating arm5between the open position P2and the closed position P1of the door. It should be noted that in the embodiment shown herein, such first portion5aand second portion5bof the activating arm5are end portions, i.e. substantially the end parts of this arm5. However, further configurations of the arm5, that provide a first portion5athereof constrained to the movable support3and a different second portion5bthereof that can be coupled, reversibly, to the aforesaid movement means6, still fall within the scope of protection requested herein.

The hinge1further comprises elastic countering means7functionally interposed between the fastening bracket2and the activating arm5.

The fastening bracket2comprises a housing24, preferably a box-like body, for accommodating the activating arm5.

With reference toFIGS. 1A, 1B and 2A, the elastic countering means7can be housed inside the housing24of the fastening bracket2. In particular, the elastic countering means7can comprise a spring7afastened to a retainer25of the housing24and a retainer26of the second portion5bof the activating arm5. For example, the spring7acan advantageously be a helical spring arranged coaxially around the drive shaft5. The expansion action of the spring7atends to lead the activating arm5towards the closed position P1of the door, preferably when the door reaches a given opening angle (e.g. less than 45°).

Some embodiments can provide that the elastic countering means7comprise a spring (not shown) functionally interposed between the fastening bracket2and an intermediate portion5cof the activating arm5, comprised between the first end portion5aand the second end portion5b.

The movement means6comprise an electric motor10and reversible connecting means9to couple and decouple selectively, or reversibly, the electric motor10and the activating arm5and, in particular, this electric motor10and the second portion5bof the activating arm5.

The hinge1is therefore configured so as to ensure that when the electric motor10is coupled to the second portion5bof the activating arm5, the actuation of the electric motor10causes the movement of the activating arm5, whereas when the electric motor10is decoupled from this second portion5b, the manual movement of the activating arm5, and therefore of its first portion5a, occurs independently of the electric motor10(i.e. without acting on the electric motor10) so as to allow a user to freely move the door of the household appliance.

In other words, when the second portion5bof the activating arm5is decoupled from the electric motor10, the user can freely move the door, substantially as if there were no movement means6, that is to say as if the hinge1was a non-motorized hinge. The second portion5bcan therefore only be coupled to the electric motor10when the movement means6are asked to move the activating arm5.

As can be better seen below, these reversible connecting means9, which can consist of a joint, such as of the coupling type, and which is functionally interposed between the electric motor10and the activating arm5, can be controlled by a special electromagnetic member, such as by a manual switch or door movement sensor or even an electric current absorption detector of the electric motor10itself for example, so as to determine the mechanical coupling or decoupling of the motor10to/from the arm5, depending on the operative requirements of the household appliance to which the hinge1is applied.

Preferably, these movement means6comprise a slider11linearly moved by means of the electric motor10. This slider11is constrained to the second portion5bof the activating arm5to move, by pushing or pulling for example, this activating arm5between the open position P2and the closed position P1of the door.

In particular, in the embodiment of the present invention shown inFIGS. 2A and 2B, the second portion5bof the activating arm5is constrained to the slider11, preferably by means of a connecting pin13, slidable inside a guide15(for example a couple of grooves or slots) arranged on the side walls of the fastening bracket2.

The guide15is preferably made so that the second end portion5bof the activating arm5can be moved along a direction parallel to the movement of the slider11.

Further embodiments can however provide that the second portion5bof the activating arm5is for example indirectly constrained to the slider11of the movement means6, for example by means of a connecting lever (not shown) functionally interposed between the second end portion5bof the activating arm5and the slider11, still remaining within the protection scope of the present invention.

With reference toFIGS. 1A and 1B, the first end portion5aof the activating arm5is constrained to the movable support3by means of a pin8. Such pin8goes through a hole made on the first end portion5aof the activating arm5and is slidable along a guide14(for example a slot) made on the movable support3.

The slot, or in general the guide14, is advantageously shaped to impose a given law of motion to the movable support3during the movement between the open position P2and the closed position P1of the door and to transmit the motion from the activating arm5to the movable support3according to certain predefined distance ratios. The shape of the slot14is selected during the design step to obtain a fluent door movement during the opening and closing thereof.

In addition to making it possible to reduce the force needed for the movement means6to move the activating arm5, this configuration makes it possible to obtain a door movement with a given pattern, such as, for example, with given accelerations or decelerations or substantially uniform (that is to say without accelerations or decelerations) during its path between the closed position P1and the open position P2.

This way, by way of example, some embodiments can provide that the electric motor10is a magnetic linear motor typically comprising a slider11arranged on a sliding guide (stator) integrated within the magnetic linear motor. The slider11is moved along the sliding guide by means of a magnetic field provided by coils arranged on the sliding guide. In this case, the slider and the sliding guide are magnetically coupled to one another when the coils are driven. When the magnetic linear motor is deactivated, the slider11freely slides on the sliding guide, in particular when this slider and the relative guide are shaped to be mutually separated by a layer of air. In this embodiment, the movement means6have the aforesaid reversible connecting means (constituted, for example, by a switch for selectively activating and deactivating the power supply of the magnetic linear motor) configured for the selective magnetic coupling and magnetic decoupling of the sliding guide and the slider11.

With reference toFIGS. 1A, 1B and 2A, in the embodiment of the invention herein shown, the movement of the slider11preferably occurs by means of a screw12of the reversible type, which is rotated by the electric motor10. The slider11is coupled, such as by means of a complementary nut screw11afor example, to the screw12, so as to transform the rotation of the screw12into a translation of the slider11.

Surprisingly, a multi-threaded screw12, preferably with more than two threads (e.g. with five threads) and with a pitch between 15 and 35 mm, preferably with a pitch between 20 mm and 30 mm (e.g. with a pitch of about 25 mm), provides optimal performance in terms of the reversibility and reduction of friction between the slider11and the screw12(with a screw-nut screw coupling). In particular, when the reversible connecting means9decouple the second portion5bof the activating arm5from the electric motor10, the translation of the slider11, due to a manual movement of the door, causes the rotation of the screw12with reduced friction. In other words, the transformation of the translatory motion of the slider11into a rotary motion of the screw12produces a substantially negligible frictional force.

With reference to the embodiment ofFIGS. 1A, 1B, 2A, and 2B, the first end portion5aand the second end portion5bof the activating arm5are rotatably constrained to each other at an intermediate portion5cof the activating arm5, for example by means of a pin17arranged perpendicularly to the moving direction of the slider11. Further embodiments can however provide that the activating arm5consists of a single piece (e.g. that the first end portion5aand the second end portion5bof the activating arm5are integral with each other) still remaining within the protection scope of the present invention.

According to a preferred aspect of this invention, the hinge1may comprise a logic control unit16intended to control, in response to one or more control signals of the manual type and/or of the type generated automatically by special sensors or system status detectors, the movement means6of the activating arm5and, in particular, at least the aforesaid reversible connecting means9to couple and decouple the electric motor10and the activating arm5.

This logic control unit16, according to an aspect of the present invention, can preferably be configured to actuate the movement means6, and/or in particular the aforesaid reversible connecting means9in response to a user actuation command. This actuation command can, for example, be imparted by means of a button and/or by means of a vocal command or other.

The logic unit16can preferably be configured to control at least the reversible connecting means9so as to couple the electric motor10to the second portion5bof the activating arm5in response to the aforesaid actuation command.

Alternatively, or in conjunction with a manual control, the actuation command of the logic unit16can be, as mentioned, imparted by sensors or by other status detection means of the system and able to detect the need to actuate the movement means6and/or operate the coupling or decoupling of the reversible connecting means9.

For example, as already mentioned, some embodiments of this invention can provide that the hinge1is equipped with means18to detect the current absorption of the electric motor10(symbolically shown with a rectangle), such as an ammeter or similar means for example. This embodiment can also provide that the aforesaid means18to detect the current absorption of the electric motor10provide an absorption value indicative of the position assumed by the activating arm5during its path between the open position P2and the closed position P1of the door.

In particular, the weight force of the door generates a moment that varies according to the position assumed by the door and causes a different current absorption of the electric motor. In other words, as the door rotates from the closed position P1towards the open position P2, the weight force acting on the door generates an increasing moment that can be detected by the means18to detect the current absorption of the electric motor. Moreover, by means of one or more cam profiles provided for example on the sliding surface between the activating arm5and the fastening bracket2, it is possible to cause easily detectable current absorption variations of the electric motor10during the path of the activating arm5between the position P1and the position P2. A logic control unit16(also symbolically shown with a rectangle) can recognize these variations and can thus associate them to one or more of the aforesaid positions of reference of the activating arm5. This way, it is possible to obtain an indication of the real position of the activating arm5with respect to the fastening bracket2.

It should be noted that further embodiments of the hinge1according to the present invention can provide that the hinge1is not directly equipped with a logic control unit16and/or means18to detect the electric current absorption of the electric motor. However, these components can be, for example, provided in a household appliance (such as an oven, for example) comprising the hinge according to the present invention. In this case, the logic control unit16and/or means18to detect the current absorption of the electric motor can be connected to the electric motor10of the hinge1and/or to the reversible connecting means9, such as by means of electric wires, or in other known ways of the art.

With reference toFIGS. 3A and 3B, the reversible connecting means9, which, as mentioned, are configured to couple and decouple selectively the electric motor10and the activating arm5, are functionally interposed, in this embodiment of the invention, between this motor10and a screw12that, as mentioned, enables the actuation of a slider11intended to transmit a pushing or pulling motion, or any other motion that allows the rotation of the door, to the activating arm5. In this embodiment, the reversible connecting means9comprise a coupling joint19provided with a first member19aconstrained to said screw12and a second member19bconstrained to the motor shaft10aof said electric motor10.

For example, this coupling joint19can be of the type comprising, on the relative rotating members19a,19b, complementary coupling profiles, such as for example with teeth or of the type with protrusions and recesses, able to transmit a torque from one member to the other19a,19bwhen they are mutually engaged.

It should be noted that a coupling joint19of this type, and in particular of the type described below, can be interposed to couple and decouple selectively any two rotating members arranged downstream of the electric motor10, independently of the use of a screw12to transform the rotary motion of the motor shaft of the motor10into the translatory, or rotary-translatory or even rotary motion of the activating arm5. In other words, independently of the arrangement used for the possible transformation of the rotary motion of the electric motor10into the motion required by the activating arm5, this coupling joint19, which belongs to a preferred embodiment of the aforesaid reversible connecting means9, can be interposed between any two rotating members, such as, for example, two shafts that transmit the rotary motion generated by the electric motor10to the motion transformation arrangement possibly positioned upstream of the aforesaid activating arm5.

With reference to theFIGS. 4A and 4B, in the embodiment herein shown, the second member19bis movable, for example axially, with respect to the first member19abetween a configuration C1of mutual engagement, wherein the rotation of the motor shaft10aof the electric motor10is transferred to the screw12, and a disengagement configuration C2, wherein the screw12is free to rotate independently of the rotation of the motor shaft10a.

Preferably, an epicyclic reduction gear20adapted to reduce the number of revolutions of the motor shaft of the electric motor10can be interposed between the second member19bof the coupling joint19and the electric motor10. In general, the reference10atherefore denotes the motor shaft moved by means of the electric motor10, this motor shaft10acan therefore be the motor shaft exiting the epicyclic reduction gear20or exiting further other stages arranged between the electric motor10and the second member19bof the coupling joint19.

Although the embodiment shown inFIGS. 4A and 4Bprovides that the second member19bis movable with respect to the first member19aof the coupling joint19, further embodiments can provide that the first member is movable with respect to the second member or that both the first and second members are movable with respect to one another, still remaining within the scope of protection of the present invention.

The first and second members19a,19bhave complementary edges, preferably provided with slightly tapered teeth (visible, for example, inFIG. 3B) adapted to engage with one another in the configuration of mutual engagement C1shown inFIG. 4A.

Preferably, the reversible connecting means9comprise elastic means22configured to lead the first and second members of the coupling joint19to the disengagement configuration C2. For example, the elastic means22can comprise a spring arranged between the first and second members19a,19bof the coupling joint19, the spring being shaped to push a member19aaway from, and thus disengaging it from, the other member19b.

In this embodiment, with reference toFIG. 3A, the reversible connecting means9further comprise an electromagnet23to lead, when they are actuated, the first and second members19a,19bof the coupling joint19to the configuration of mutual engagement C1. This actuator23is preferably controlled by the logic control unit16(as symbolically shown inFIGS. 1A, 1B and 2A).

In particular, in response to a user actuation command and/or in response to an actuation command generated automatically by sensors or detectors of the hinge1or by the household appliance, the logic control unit16actuates (i.e. energizes) the electromagnet23, which moves the second member19bof the coupling joint19towards the configuration of mutual engagement C1shown inFIG. 4A. Once the configuration of mutual engagement C1has been reached, the logic control unit16controls the actuation of the electric motor10. In particular, in the embodiment of the invention herein shown, the electric motor10is actuated to rotate the screw12in one direction or in the opposite direction depending on the position of the door. This position can, for example, be detected by an encoder configured to detect the number of revolutions accomplished by the electric motor10or with known means detecting the position of the door, or with microswitches automatically operated depending on the position of the door itself, or even preferably with means18to detect the electric current absorption of the motor10previously described.

When the electric motor10is actuated, the rotation of the motor shaft10a, i.e. the relative torque, is transferred from the second member19bto the first member19aof the coupling joint19and therefore to the screw12that translates the slider11to move the activating arm5between the closed position P1and the open position P2of the door.

When one of the aforesaid positions P1, P2has been reached, variously detected as mentioned above, the logic control unit16controls the switching off of the electric motor10and of the electromagnet23. By means of the spring22arranged between the first and second members19a,19bof the coupling joint19(and possibly by means of a spring22provided on the electromagnet23), the coupling joint19is led into the disengagement configuration C2wherein the electric motor10and the screw12are decoupled.

In this configuration, the manual movement of the door by a user can be carried out effortlessly, substantially as if there were no movement means6.

This solution is advantageous also in case of absence of electric current while the door is being moved by means of the movement means6. In particular, if the electric current is interrupted during the movement of the door by means of the electric motor10, the electromagnet23is no longer energized, the electric motor is inactive and the screw12stops. In this case, the elastic force of the spring22brings the first member19aaway from the second member19bof the coupling joint19, leading them in the disengagement configuration C2and therefore decoupling the electric motor10from the screw12.

In this configuration, the door can, for example, be brought back towards the closed position P1by means of the elastic countering force acting on the activating arm5, provided by the elastic countering means housed in the fastening bracket2.

In order to simplify the design of the hinge1, the movement means6can advantageously comprise a connecting bracket27configured to rotatably constrain the electric motor10to the household appliance compartment. In particular, between the closed position P1and the open position P2of the door, the movement of the activating arm5causes a rotation of the connecting bracket27to which the electric motor10is fastened.

If the movement means6comprise, by way of example, the screw12of the embodiment herein shown, this rotation occurs both when the electric motor10is coupled to the screw12and when the electric motor10is decoupled from it.

In particular, during the disengagement configuration C2between the first and second members19a,19bof the coupling joint19, the screw12can freely rotate following the translation of the slider11caused by the manual movement of the door. In order to further reduce the friction, the screw12can preferably be supported by means of a ball bearing28(visible inFIG. 3B) arranged inside a casing29inside which the screw12itself is housed. The slider11further comprises a tubular element30arranged coaxially with the screw12inside the casing29. The rotation of the connecting bracket27makes it possible to substantially maintain the tubular element30of the slider1coaxial with the screw12by further reducing the friction and therefore increasing the fluidity of the manual movement of the door when the electric motor is decoupled from the activating arm5.

Finally, it should be noted that although selective connecting means9of the type comprising a coupling joint19are described herein, other selective connecting means, for example acting directly on the electric motor10or on its components such as for the magnetic linear motor mentioned, a linear electric motor or any other type known in the art and able to interrupt or connect the mechanical members to one another for the transmission of motion, can be used without for this reason departing from the scope of the present invention.