CAM TYPE

TECHNICAL FIELD

The present invention generally relates to an electrically operated actuating unit of the articulated lever or cam type. In particular, the present invention relates to actuating units of the articulated lever or cam type typically used in the field of sheet metal working, for example for the construction of motor vehicle bodies.

BACKGROUND

In the context of the construction of motor vehicle bodies, it is known to use various types of actuating units including actuating units for blocking sheets to be welded, rotating units for moving groups of blocking units, centring units for the correct positioning of sheets on equipment through appropriate references and so on.

For this purpose, the known actuating units comprise a closing device that is movable between a first operating position and a second operating position in which the closing device reaches a condition of irreversibility. Once the condition of irreversibility is triggered, the closing device is able to remain in the second operating position even in the absence of an actuation command. The closing device is connected to an actuating arm to move it between an open position and a closed position, wherein the closed position of the actuating arm corresponds to the second operating position of the closing device, in a condition of triggered irreversibility. These actuating units are generally controlled through a pneumatic or electric actuator which acts on an element that is axially movable between two end positions and through which the actuator acts on the closing device to move it between the first and second operating position. In general terms, the axially movable element acting on the closing device can be made in the form of a rod with an end shaped like a fork, trolley or other.

Electrically operated actuating units usually have design problems since it is complex to maintain the same overall dimensions as the corresponding pneumatically operated actuating units, i.e. pneumatically operated actuating units of the same model.

Actuating units of the articulated lever or cam type present on the market today are in fact made according to predetermined "models" specifically defined by industrial standards in terms of dimensions (in order to ensure interchangeability) and actuation, which in the specific case of pneumatic control is translated into "sizes" of the drive cylinders.

Owing to the nature of the electric drives traditionally used in the electrically operated actuating units, in fact, the action is imparted through a rotationally driven stem, therefore requiring special gears for transforming the rotary motion into a linear translation of the control rod which acts on the closing device, which gears generally require additional overall dimensions.

By way of example, document DE 102013005 484 describes an actuating unit provided with an electric actuator which brings a threaded spindle on which a nut screw engages into rotation. A carriage provided with a pair of rollers constrained to slide longitudinally in a track parallel to the spindle is connected laterally, in an integral manner, to the nut screw. The carriage is in turn pivoted to the closing device to guide it between the first and second operating position. This configuration, in addition to requiring greater lateral dimensions to accommodate the spindle at the side of the closing device, is not particularly effective in imparting the pushing action on the closing device as the carriage slides along an axis parallel to the movement axis of the nut screw. Document DE 11 2012 005 764 describes an actuating unit provided with an electric actuator which brings a threaded spindle into rotation, causing in turn the rotation of a gear pivoted to the actuating arm of the unit. Document EP 1 431 001 describes an actuating unit provided with a pair of electric actuators which, through respective toothed wheel gears, bring a nut screw crossed by a threaded rod locked to rotation into rotation. The clockwise or counterclockwise rotary movement of the nut screw causes a linear forward or backward translation of the threaded rod. The actuating unit described in EP 1 431 001 has increased overall dimensions due to the need to house, inside the unit, the toothed wheel gears and the nut screw, as well as necessarily to have to arrange the electric actuators in an offset manner with respect to the threaded rod. Finally, document EP 1 464 445 describes an actuating unit provided with an electric actuator which brings a threaded spindle on which a nut screw housed inside a hollow rod engages, in turn hinged to the closing device into rotation. A planetary reducer is also interposed between the electric actuator and the spindle. Also in this case, the need to house a reducer and the nut screw inside the body of the unit leads to an overall increase in the overall dimensions of the unit. Furthermore, the actuating unit described in EP 1 464 445 does not allow a mechanical adjustment of the open position, but requires that this position be set by means of suitable software and position detectors.

The Applicant has also pointed out that, in addition to the problems of overall dimensions, the known electrically operated actuating units have the disadvantage of strong wear due to the number of interacting parts, used to transfer the command imparted by the actuator to the closing device.

Last but not least, the Applicant has perceived the need to realise an electrically operated actuating unit which allows minimizing the interventions necessary to convert an electrically operated unit into a pneumatically operated unit and vice versa, thus conceiving a solution that incorporates as much as possible the geometry and the structural characteristics of the pneumatically operated actuating units.

In particular, the Applicant has recognised the importance of maintaining the possibility of a mechanical adjustment of the opening angle.

OBJECTS AND SUMMARY OF THE INVENTION

In light of the above, the problem underlying the present invention is that of devising an actuating unit capable of overcoming the drawbacks of the prior art.

Within the context of this problem, an object of the present invention is to realise an electrically operated actuating unit of the articulated lever or cam type capable of maintaining the same overall dimensions or reducing the overall dimensions with respect to pneumatically operated actuating units of the same model.

Another object of the present invention is to realise an electrically operated actuating unit of the articulated lever or cam type which has a reduced number of gears for transforming the rotary command imparted by the electric actuator into a translational motion of the rod acting on the closing device.

In accordance with a first aspect thereof, the invention therefore concerns an actuating unit of the articulated lever or cam type comprising an actuating arm rotatable between an open position and a closed operating position. A closing device is also provided configured to bring the actuating arm into rotation between the open position and the closed operating position, wherein the closing device comprises a mechanism for movement irreversibility configured to trigger when the actuating arm reaches the closed operating position. The actuating unit also comprises an electric actuator comprising an electromagnetic stator and a magnetic rotor, and a control rod functionally interposed between the electric actuator and the closing device, movable into translation along an actuation axis under the action imparted by the electric actuator for controlling the movement of the closing device, the electric actuator comprising a control stem coaxial to the magnetic rotor and connected to the control rod according to an arrangement coaxial to the actuation axis. Advantageously, the control stem is fixed to rotation.

The Applicant has identified that thanks to the particular configuration of the control stem of the actuator it is possible to realise an electrically operated actuating unit which is as compact and at the same time robust as a pneumatically controlled actuating unit.

In fact, the stem fixed to rotation and coaxial to the actuation axis allows avoiding special drive return gears which, in addition to affecting the overall dimensions of the actuating unit, may be subject to wear.

Furthermore, the electrically operated actuating unit according to the invention is substantially convertible into a pneumatically operated actuating unit of the same size by simply replacing the actuator. In fact, both actuators impart the command through the translation of a control stem.

The present invention may have at least one of the following preferred features; the latter may in particular be combined with one another as desired in order to meet specific application needs.

In a variant of the invention, the magnetic rotor is shaped like a hollow cylinder and is arranged inside the electromagnetic stator coaxially with the same.

Preferably, the hollow cylindrical magnetic rotor is solidly constrained to a nut screw coaxial with the same which engages at least one external thread of the control stem, so that a rotation of the cylindrical rotor causes a translation of the control stem.

Alternatively, the hollow cylindrical magnetic rotor is internally threaded and engages at least one external thread of the control stem, so that a rotation of the cylindrical rotor causes a translation of the control stem.

This particular configuration of the electric actuator means that the rotor can house the control stem inside it according to a coaxial arrangement, also allowing a translational movement to be transferred to it.

Preferably, the external thread of the control stem is configured to allow the reversibility of the control stem in case of external action imparted on the actuating arm.

Advantageously, this expedient facilitates installation operations by allowing the actuating arm to be moved in the absence of an electric control, without necessarily having already finalized the electrical connection.

Preferably, the external thread of the control stem is configured to ensure the irreversibility of the control stem in the absence of a command imparted by the electric actuator.

Advantageously, this expedient ensures that the actuating unit is able to maintain the open condition even in the absence of a command, for example in the event of a power failure of the electric actuator.

Preferably, the electromagnetic stator comprises a plurality of coils with a winding axis which is arranged radially with respect to the actuation axis and the hollow cylindrical magnetic rotor comprises a plurality of permanent magnets arranged on a rotor mantle, parallel to the actuation axis and with alternating polarity with respect to adjacent magnets.

This specific conformation of the actuator allows it to be realised in a particularly compact manner, with overall dimensions comparable to or smaller than a pneumatic cylinder of the corresponding size.

In a variant of the invention there is also provided a rotation locking and sliding group which acts on the control stem so as to lock the same with respect to a rotary movement.

Preferably, the rotation locking and sliding group comprises at least one roller free to rotate about a respective pin housed according to an arrangement transverse to the actuation axis, and the thread of the control stem is flattened on at least one sliding face which extends parallel to the actuation axis, the sliding face cooperating with the sliding roller so as to enable the linear sliding of the control stem in the absence of rotation.

Advantageously, the presence of a rotation locking and sliding group and the particular shape of the stem ensure that the control stem performs a strictly linear movement, thus avoiding the transfer of torques to the closing device which could lead to damaging the same.

In a variant of the invention, the control stem is internally hollow and houses a first portion of the control rod according to a mutual coaxial arrangement which is fixed and axially adjustable. Preferably, the actuating unit additionally comprises means for adjusting the open position comprising:

- a first toothed element placed at a free end of the control stem and coaxial with it, the first toothed element being constrained with respect to the control stem so as to be free to rotate and fixed in translation, the first toothed element being threaded internally and engaging a threaded portion of the control rod; and

- at least one second toothed element rotatable about an axis transverse to the actuation axis and configured to go into engagement with the first toothed element, so that a rotation imparted to the second toothed element about the transverse axis causes a rotation of the first toothed element about the actuation axis.

These expedients allow to mechanically adjust the angular open position of the actuating arm, thus maintaining the same characteristics of the pneumatic units. This makes the use of electrical units highly simple for operators generally used to working with pneumatic units. The interchangeability of the pneumatic and electric units is thus particularly facilitated and increased.

Preferably, the first toothed element comprises a sleeve externally provided with a crown gear, and a nut screw integral with the sleeve and which engages a radially protruding portion of the control stem.

In this way it is advantageously ensured that the first toothed element is fixed to the control stem in a manner fixed to translation, being able on the contrary to rotate about the actuation axis by means of the action imparted on the crown gear.

Preferably, the actuating unit comprises temporary rotation blocking means configured to lock the rotation of the first toothed element about the actuation axis when disengaged from the second toothed element.

More preferably, the temporary blocking means comprise a plurality of elastic means interposed between the first toothed element and the free end of the control stem, wherein each elastic means acts on a respective spherical element to force it into corresponding seats made in the free end of the control stem.

Advantageously, this expedient makes it possible to prevent the first toothed means from screwing along the control rod during normal use of the actuating unit. However, the retaining action exerted by the temporary blocking means on the first toothed element can be easily overcome through the rotation imparted to the same by the at least one second toothed element. According to a variant of the invention, the actuating unit comprises a housing body inside which the closing device is arranged, the electric actuator being fixedly connected to the housing body of the closing device.

Preferably, the nut screw is housed in the electromagnetic stator so as to be free to rotate and fixed to translation and/or has an enlarged collar which develops by interposition between the hollow magnetic rotor and an upper cover of the electromagnetic stator. For example, the enlarged collar develops between the hollow magnetic rotor and the housing body of the closing device.

In this way a translation of the nut screw along the actuation axis A is effectively prevented.

In a variant of the invention, a portion of the control rod is slidably housed inside a sliding seat that is coaxial with the actuation axis A. Furthermore, the portion of the control rod comprises at least one pair of sliding rollers that are configured to guide the sliding of the rod inside the sliding seat.

Conveniently, this conformation of the control rod prevents it from rotating about the actuation axis A, for example following the rotation imparted to the first toothed element of the means for adjusting the open position.

In a variant of the invention, the actuating unit comprises an encoder associated with the magnetic rotor and configured to monitor the instantaneous position of the stem as a function of the number of revolutions performed by the rotor.

In a variant of the invention, the actuating unit comprises means for adjusting the position of the control stem comprising:

- a first toothed element placed at the upper end of the nut screw and integral with it; and

- at least one second toothed element rotatable about an axis transverse to the actuation axis and configured to go into engagement with the first toothed element, so that a rotation imparted to the second toothed element about the transverse axis causes a rotation of the first toothed element about the actuation axis.

Preferably, the first toothed element is made in the form of a crown gear with a conical conformation and the second toothed element is made in the form of a gear provided, at a first end thereof, with a conical toothed head configured to go into engagement with the first toothed element and being accessible, at a second end thereof, through a side opening provided on the housing body for controlling rotation of the gear about the transverse axis.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will be more evident from the following description of some preferred embodiments thereof made with reference to the appended drawings.

The different features in the individual configurations can be combined with each other as preferred according to the previous description, should it be necessary to avail of the advantages resulting specifically from a particular combination.

In such drawings,

- Figures la and lb are side elevation views of an electrically operated actuating unit according to the invention, specifically a locking unit, respectively in the closed configuration with triggered irreversibility mechanism and in the open configuration;

- Figure 2 is a partially cut-out perspective view of an electrically operated actuating unit according to a first embodiment of the invention from which the actuating arm has been removed for simplicity's sake of representation;

- Figure 3 is a sectional view of the actuating unit of Figure 2 according to a first vertical plane of section passing through the actuation axis A;

- Figure 3 a is an enlarged detail of Figure 3; - Figure 4 is a sectional view of the actuating unit of Figure 2 according to a second vertical plane of section passing through the actuation axis A, orthogonal to the first vertical plane;

- Figure 5 is a sectional view of the actuating unit of Figure 4 according to an orthogonal sectional plane indicated in Figure 4 with plane C-C; and

- Figures 6a and 6b are respectively a sectional view and a partially cut-out perspective view of an electrically operated actuating unit in line with a second embodiment of the invention from which the actuating arm has been removed for simplicity's sake of representation; and

- Figures 7a and 7b are respectively a sectional view and a partially cut-out perspective view of an electrically operated actuating unit according to a third embodiment of the invention from which the actuating arm has been removed for simplicity's sake of representation.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, for the illustration of the figures, identical numbers or reference symbols are used to indicate construction elements with the same function. Further, for illustration clarity, some references may not be repeated in all the figures.

While the invention is susceptible to various modifications and alternative constructions, certain preferred embodiments are shown in the drawings and are described hereinbelow in detail. However, it is to be understood that there is no intention to limit the invention to the specific embodiment illustrated but, on the contrary, the invention intends to cover all the modifications, alternative and equivalent constructions that fall within the context of the invention as defined in the claims.

The use of “for example”, “etc.”, “or” indicates non-exclusive alternatives without limitation, unless otherwise indicated. The use of “comprises” and “includes” means “comprises or includes, but not limited to”, unless otherwise indicated.

With reference to Figures la and lb, an articulated lever actuating unit according to the present invention is illustrated, indicated as a whole with 10, specifically made in the form of a locking unit.

Figures 2-4 show a first preferred embodiment of the articulated lever actuating unit according to the present invention. The locking unit 10 comprises a housing body 11 inside which a locking device 30 of the articulated lever or toggle type (shown in Figures 2 and 3) is arranged and is movable between a first operating open position (not illustrated) and a second closed operating position (illustrated in Figures 2 and 3).

The locking unit 10 further comprises an electric actuator 20 provided with an actuator body 23 fixedly connected to the housing body 11 of the closing device 30. The electric actuator 20 comprises a control stem 21 movable linearly along an actuation axis A between two end positions, of which a first position retracted inside the body 23 of the actuator and a second position of maximum protrusion from the body 23 of the actuator. The control stem 21 has a thread on its external mantle. In the embodiment of Figures 2-4, the threaded stem 21 is internally hollow and houses a first portion of a control rod 16 according to a mutual coaxial arrangement which is fixed and axially adjustable. A second portion of the rod 16, protruding from the threaded stem 21, is slidably housed inside a sliding seat 11a of the housing body 11 coaxial to the actuation axis A, and has a fork termination connected to the closing device 30 inside the housing body 11 to move it between the first and second operating position. The first and second operating position of the closing device 30 correspond respectively to the two end positions between which the threaded stem 21 of the actuator 20 is movable, which in turn brings the rod 16 inside the sliding seat 11a into translation. The rod 16 comprises two pairs of sliding rollers 16a which guide the sliding of the rod inside the sliding seat 11a, preventing a rotation thereof.

Also provided are means for detecting the position 14 and a set of levers 15 which cooperate in a per se known manner with the rod 16 to signal that the end positions delimiting the stroke of the rod 16 have been reached and therefore the first or the second operating position of the closing device 30 have been reached.

In detail, the closing device 30 comprises a connecting rod 31 and a crank 32 connected to each other rotatably about a first axis orthogonal to the actuation axis, substantially at a respective end. The rod 16 is constrained to another end of the connecting rod 31 of the closing device 30 rotatably about a second axis orthogonal to the actuation axis A. The crank 32 is constrained to the housing body 11 to another of its own end rotatable about a third axis orthogonal to the axis A and is provided with a pair of coaxial pins 12 which protrude from opposite sides of said housing body 11. At least one actuating arm 13 (shown - for clarity's sake of illustration - only in Figures la and lb) is integrally constrained to the coaxial pins 12 and is therefore brought into rotation by the movement of the crank 32.

The fixed adjustable connection between the threaded stem 21 and the rod 16 is set by means for adjusting the open position 17,18 which comprise a first toothed element 17 placed at a free end 21c of the stem 21 and constrained with respect to the same so as to be free to rotate and fixed to translation. In the embodiment illustrated by way of example, the first toothed element 17 is made in the form of a sleeve and is kept in a fixed axial position with respect to the threaded stem 21 using a ring nut 17b screwed onto the same 17 which abuts against a radially protruding portion of the stem 21.

The sleeve 17 comprises externally a crown gear 17a with a conical shape through which it is possible to impart a rotation to the sleeve 17. Furthermore, the sleeve 17 is internally threaded and engages on a threaded portion of the rod 16, so that a rotation of the sleeve 17 leads to a relative axial translation between the rod 16 and the sleeve 17 and, consequently, between the rod 16 and the stem 21.

The means for adjusting the open position 17,18 further comprise at least a second toothed element 18 which in the embodiment illustrated is made in the form of a gear provided, at a first end thereof, with a conical toothed head 18a configured to go into engagement with the crown gear 17a of the sleeve 17. The gear 18 is arranged at the base of the housing body 11 so that its first end ends substantially at the sliding seat 11a of the rod 16 and a second end thereof faces laterally from an opening lib provided on the housing body 11. In the illustrated embodiment, two gears 18 are provided which are accessible from respective side openings lib provided on opposite sides of the housing body 11.

Each gear 18 can be moved along an axis transverse to the actuation axis A to be brought from a position of disengagement with the crown gear 17a to a position of engagement with the crown gear 17a. In the engagement position, a rotation of the gear 18 about the transverse axis causes a rotation of the sleeve 17 about the actuation axis A and, consequently, an adjustment of the mutual axial position between the stem 21 and the rod 16. A respective elastic return means (not illustrated) acts on each gear 18 to bring the gear 18 back to the position of disengagement from the sleeve 17 when not forced to assume the engagement position.

The body of the sleeve 17 comprises temporary rotation blocking means 19 that are configured to prevent a screwing of the sleeve 17 during normal operation of the actuating unit 10. These temporary blocking means 19 exert a force to counteract the rotation sized so that it can be easily overcome by the action imparted through the gears 18. The temporary rotation blocking means 19 comprise a plurality of elastic means 19a interposed between the crown gear 17a of the sleeve 17 and the free end 21c of the stem 21. Each elastic means 19a acts on a respective spherical element 19b to force it into corresponding seats 2 Id made in the free end 21c of the stem 21.

The electric actuator 20 is advantageously of the hollow shaft type, such as for example a torque motor, and comprises a cylindrical electromagnetic stator 23, which cooperates with a corresponding hollow magnetic rotor 24, it thus also having a cylindrical shape. A nut screw 22 is also provided, integrally constrained to the hollow magnetic rotor 24. In particular, in the illustrated embodiments, the electromagnetic stator 23 acts as the body of the actuator.

In a possible variant of the invention, not illustrated, the electromagnetic stator is made as a stand-alone element, integrally constrained to the body of the actuator. Furthermore, in a possible variant of the invention not illustrated, the hollow magnetic rotor 24 has an internal thread, it acting as a nut screw.

Preferably, the electromagnetic stator 23 comprises a plurality of coils (not illustrated) with a winding axis which is radial with respect to the actuation axis A. The hollow magnetic rotor 24 comprises a plurality of permanent magnets (not illustrated) with an elongated conformation, for example, of the tile or parallelepiped type, arranged on the cylinder mantle, parallel to the actuation axis A and with alternating polarity with respect to the adjacent magnets.

The nut screw 22 is constrained to the body 23 of the actuator so as to be free to rotate and fixed to translation. To this end, the nut screw 22 has an enlarged collar 22a which develops by interposition between the hollow rotor 24 and an upper cover 25 placed as an upper closure of the electromagnetic stator 23. This interposed arrangement ensures that the nut screw 22 is locked to translation. The nut screw 22 has a thread internally in which the threaded stem 21 engages so that a rotation of the nut screw 22 induced by the cylindrical rotor 24 causes a translation of the threaded stem 21.

The upper cover 25 of the stator 23 acts as an interface for the connection to the body of containment 11 of the closing device 30. Inside the upper cover 25 there is a rotation locking and sliding group 26 which acts on the threaded stem 21 so as to ensure that it is only moved in translation, thus allowing a relative rotation between the stem 21 and the nut screw 22. The group 26 comprises a pair of rollers 26a that are free to rotate about respective pins 26b housed in own seats 25a of the cover 25 according to an arrangement transverse to the actuation axis A. In particular, the thread of the threaded stem 21 is flattened on two parallel sliding faces 21a, made on the mantle of the stem 21, which extend parallel to the actuation axis A and are connected to each other by means of two portions 21b in which the thread is not flattened. Each flattened thread face 21a cooperates with a sliding roller 26a included in the group 26 so as to enable a linear sliding of the control stem 21 in the absence of rotation.

The electromagnetic stator 23 is closed at the bottom by a lower cover 27 which carries an encoder 28 for monitoring the instantaneous position of the stem 21, as a function of the number of revolutions performed by the rotor 24 and detected by the encoder 28.

Figures 6a and 6b show a second preferred embodiment of the articulated lever actuating unit according to the present invention comprising an electric actuator 20 of the hollow shaft type provided with a cylindrical electromagnetic stator 23, which cooperates with a corresponding hollow magnetic rotor 24, it thus also having a cylindrical conformation. Inside the cylindrical rotor 24 and constrained thereto there is a nut screw 22 in which the threaded stem 21 engages so that a rotation of the cylindrical rotor 24, and with it of the nut screw 22, causes a translation of the threaded stem 21.

The embodiment of figures 6a and 6b differs from the embodiment of figures 2-4 in particular in that the threaded stem 21 is constrained to the control rod 16 according to a mutual coaxial arrangement which is fixed and not adjustable. For this reason, in this embodiment there are no specific expedients configured to prevent a rotation of the stem (for example a flattened thread portion which cooperates with a rotation locking and sliding group). A rotation could in fact be induced, for example, when adjusting the mutual position between the stem and the rod, an adjustment however not being provided in the actuating unit according to the embodiment of figures 6a and 6b.

According to this embodiment, the adjustment of the open position, i.e. the position of maximum insertion of the threaded stem 21 inside the actuator body, constituted in this case by the stator 23, is electronically adjusted through a measurement signal delivered by the encoder 28 which, suitably processed, delivers a measurement of the instantaneous position of the control rod 16. Similarly, the second embodiment illustrated in Figures 6a and 6b does not have means for detecting the end positions delimiting the stroke of the control rod since the instantaneous position of the rod 16 is detected by means of the measurement signal delivered by the encoder 28. However, a display 14’ is provided, for example comprising one or more LED indicators, to signal that the end positions of the rod 16 have been reached, when the encoder 28 delivers a measurement signal corresponding to these positions.

Figures 7a and 7b show a third preferred embodiment of the articulated lever actuating unit according to the present invention in which, like in the case of the embodiment of Figures 6a and 6b, the threaded stem 21 is constrained to the control rod 16 according to a mutual coaxial arrangement which is fixed and not adjustable.

Specifically of the embodiment of Figures 7a and 7b, the external thread of the control stem 21 is configured to allow the reversibility of the control stem 21 in the event of a manual action imparted directly or indirectly on the stem, in the absence of an actuating command.

The embodiment of figures 7a and 7b also comprises means 17’, 18’ for adjusting the position of the control stem 21 which comprise a first toothed element 17’ placed at the upper end of the nut screw 22 and integral therewith and at least a second toothed element 18’ configured to go into engagement with the first toothed element 17’.

In the embodiment illustrated by way of example, the first toothed element 17’ is made in the form of a conical crown gear. Furthermore, the at least one second toothed element 18’ is made in the form of a gear provided, at a first end thereof, with a conical toothed head which is configured to go into engagement with the first toothed element 17’. The gear 18’ is arranged at the base of the housing body 11 so that its first end ends substantially at the first toothed element 17’ and a second end thereof faces laterally from an opening lib provided on the housing 11, being thus possible to access and control a movement of the gear 18’ through said opening lib. Through said opening lib, the at least one gear 18’ can be moved along an axis transverse to the actuation axis A so as to be brought from a position of disengagement with the crown gear 17’ to a position of engagement with the crown gear 17’. In the engagement position, a rotation of the gear 18’ about the transverse axis causes a rotation of the crown gear 17’ about the actuation axis A and, consequently, a rotation of the nut screw 22 integral with the crown gear 17’. This in turn causes a translation of the control stem 21.

The action imparted through the means 17’, 18’ for adjusting the position of the stem 21 thus allows the actuating arm to be moved even in the absence of an electric command. This facilitates the initial installation operations, allowing the actuating arm to be moved without necessarily having already finalized the electrical connection of the actuating unit. Furthermore, the action imparted through the means 17 ’,18’ for adjusting the position of the stem 21 can also be used to manually release the closing device 30 from the condition of irreversibility.

The operation of the actuating unit 10’ according to the present invention is the following.

The activation of the electric actuator 20 causes a translation of the control stem 21. The electrical supply of the electromagnetic stator 23 consisting of the plurality of radial coils leads, in fact, to generating radial forces which alternately attract and repel the permanent magnets arranged on the mantle of the cylindrical rotor 24, which is therefore moved in rotation. This rotation of the cylindrical rotor 24 causes the translation of the control stem 21 due to the engagement between the external threaded portion of the stem 21 with the internal thread of the rotor 24 given by the nut screw 22 integral therewith.

In this way it is possible to move the control stem 21 to slide along the actuation axis A, bringing the closing device 30 from an open configuration to the closing configuration with triggered irreversibility mechanism, illustrated in the figures. In this way, the actuating arm 13 is moved between the open position and the closed operating position.

The linear sliding of the control stem 21 is also enabled by the sliding and locking group 26 which cooperates with the two sliding faces 21a of the stem to prevent a rotation thereof. With specific reference to the embodiment of Figures 2-4, it is also possible to adjust the angular position at which the actuating arm 13 is in the open condition, i.e. the angle of the open position. This angular position is caused by the overall length of the assembly consisting of the stem 21 and the control rod 16, which in turn generates the length of the maximum stroke that the assembly consisting of stem 21 and rod 16 can travel to reach the closed operating position. To this end, it is necessary to bring the actuating arm 13 into the open position. In this condition, the first toothed element 17 is positioned at the base of the housing body 11 where the second toothed elements 18 can act. A second toothed element 18 is therefore brought into engagement with the first one 17 and made to rotate about the axis transverse to the actuation axis A. This causes a rotation of the first toothed element 17 about the actuation axis A and, consequently, a relative translation between the control rod 16 and the control stem 21. In fact, the threaded portion inside the first toothed element 17 in which a threaded portion of the control rod 16 engages makes the rotation of the first toothed element 17 result in a translation of the control rod 16.