Drive unit for a rolling barrier

Abstract

Drive unit of a rolling barrier, comprising: - a tubular body (2) having a main development direction (D) and a first and a second end (2A, 2B); - a motor (3) designed to rotate the tubular body (2); - a support body (4) having an accommodation seat (40); - a safety device (5) housed in the seat (40) of the support body (4) and comprising a centrifugal brake (50) operatively coupled to the tubular body (2) in use, the safety device (5) being designed to engage when a predetermined rotational speed of the tubular body (2) is exceeded and to block rotation of the tubular body (2); - at least one torsion spring (7) having a first end (7A) coupled to the motor (3) to be set in rotation; - a first sensor (9) designed to detect a signal relating to a state of the torsion spring (7).

Description

[0001] This invention relates to a drive unit of a rolling barrier.

[0002] When it comes to blocking off rooms or areas such as garages, shops, rooms, etc., there are various types of barrier walls, including roller doors and motorized roller shutters.

[0003] The drive unit with which the state-of-the-art roller doors or shutters are equipped has several disadvantages both in terms of ease of installation and maintenance as well as safety.

[0004] In general, the drive units include a motor for moving the rolling wall, a torsion spring and a safety device, which may, for example, be of the catch type.

[0005] The torsion spring is automatically tensioned when the barrier wall is lowered, absorbs elastic energy and reduces the force required by the motor (or the user in the case of manual operation) when raising the wall by counteracting the weight of the wall.

[0006] As a rule, the safety gear is located outside the other elements of the unit and interacts with the torsion spring.

[0007] There is a need to produce a drive unit that is characterized by particularly practical installation and is also suitable for small areas.

[0008] In addition, there is a need to report any problems with the drive unit, such as a broken spring.

[0009] The object of this invention is to provide a drive unit for a rolling barrier that meets the above-mentioned needs.

[0010] The stated technical problem is essentially solved by a drive unit of a barrier wall which comprises one or more of the technical features listed in the appended claims and the description.

[0011] This description is described below with reference to the drawings attached as a non-limiting example. In the drawings: - Fig. 1 a drive unit of a barrier wall in a perspective view according to this description according to a first embodiment; - Fig. 2 an exploded view of the drive unit from Fig. 1; - Fig. 3 a section of the drive unit Fig. 1; - Fig. 4 shows a detail of a drive unit of a barrier wall in a perspective view according to this description according to the first embodiment; - Fig. 5 shows a detail of a drive unit of a barrier wall in a perspective view according to the first embodiment; - Fig. 6 and Fig. 7 respective perspective views of the detail from Fig. 5 with an activation disc in two different positions; - Fig. 8 shows a detail of a drive unit of a barrier wall in a perspective view according to this description according to the first embodiment; - Fig. 9 a perspective view of the detail from Fig. 8 in disassembled condition with one component removed; - Fig. 10 a perspective view of the detail from Fig. 8 in disassembled condition; - Fig. 11 and Fig. 12 is a partially assembled perspective view and a perspective exploded view of a safety gear of a drive unit of a barrier wall in a perspective view according to this description; - Fig. 13 a drive unit of a barrier wall in a perspective view according to this description according to a second embodiment; - Fig. 14 an exploded view of the drive unit from Fig. 13; - Fig. 15 and Fig. 16 shows a detail of a drive unit of a barrier wall in a perspective view according to this description according to the second embodiment in two different configurations; - Fig. 17 and Fig. 18 an enlargement of some details of the Fig. 15 and Fig. 16.

[0012] This invention relates to a drive unit 1 of a rolling barrier. According to the invention, the drive unit of a rolling barrier comprises the following: - a tubular body 2 having a main development direction D and a first and a second end 2A, 2B; - a motor 3 designed to rotate the tubular body 2; - a support body 4 having an accommodation seat 40; - a safety device 5 housed in the seat 40 of the support body 4 and comprising a centrifugal brake 50 operatively coupled (directly or indirectly) to the tubular body 2 in use, the safety device 5 being designed to engage when a predetermined rotational (angular) speed of the tubular body 2 is exceeded and to block rotation of the tubular body 2; - at least one torsion spring 7 having a first end 7A operatively coupled (preferably indirectly) to the motor 3 to be set in rotation; - a first sensor 9 (preferably a switch) designed to detect a signal relating to a condition (preferably breakage and / or relaxation) of the torsion spring 7.

[0013] According to another aspect, the first sensor 9 is associated with the support body 4, in particular attached thereto.

[0014] It should be noted that the drive unit preferably comprises a first sensor 8 which is arranged in the support body 4 and designed to detect an actuation of the centrifugal brake 50.

[0015] Both illustrated embodiments, the first and the second, share the concept which is the subject of claim 1; the actual differences between these embodiments will be clarified below.

[0016] According to one aspect of this description, the drive unit comprises an activation body 20 which is partially rotatable with respect to the support body 4.

[0017] In addition, the torsion spring 7 preferably has a first end 7A which is operatively connected (directly or indirectly) to the motor 3 in order to be set in rotation, and a second end 7B which is operatively connected directly or indirectly to the activation body 20.

[0018] The term “indirect connection” means that one element can be connected to another by means of additional elements, while the term “direct connection” means that one element can be connected to another without additional elements.

[0019] It should be noted that, unless stated whether the connection is direct or indirect, it is to be assumed that it can be implemented in either way, depending on the embodiments. It should be noted that the first sensor 9 is designed to switch between a first and a second angular position (i.e., to change the logical state) as a result of rotation of the activation disc 20.

[0020] It should be noted that the term "partially rotatable" with respect to the activation disc 20 is to be understood in such a way that the activation body 20 does not perform a complete rotation, ie over 360°, with respect to the support body 4, but a rotation over a predetermined angle of rotation (less than 360°).

[0021] This aspect is explained in more detail below.

[0022] According to another aspect, the activation body 20 is designed to rotate with respect to the support body 4 by an angle of less than 45° (preferably by an angle of less than 15°).

[0023] To enable the "partial rotation" of the activation body 20 with respect to the support body 4, either the activation body 20 or the support body 4 comprises limiting recesses 23A, and the other element, either the support body 4 or the activation body 20, comprises projections 23B designed to fit into the recesses 23A, wherein the limiting recesses 23A and the projections 23B are designed to define limitations on the partial rotation of the activation body 20 with respect to the support body 4.

[0024] The use of this partial rotation with respect to the signal from the first sensor 9 is described in more detail below.

[0025] According to the second embodiment, the activation body 20 comprises a housing seat 21.

[0026] The second end 7B of the spring 7 is fixed to the activation body 20 and inserted into the accommodation seat 21.

[0027] According to the first embodiment, the activation body 20 has the shape of a disc.

[0028] In such a first embodiment, the drive unit further comprises a body 22 for fastening the spring 7, to which the second end 7B of the spring 7 is directly fastened; in this first embodiment, the activation body 20 is coupled to (ie, fastened to) the fastening body 22.

[0029] According to another aspect, the activation body 20 has an activation projection 24A or an activation recess (shown in the Fig. 10 and Fig. 17) which are designed to engage with the first sensor 9 (in particular with the activation element of the first switch 9) when the activation body 20 is in a predetermined angular position with respect to the support body 4.

[0030] In practice, the arrangement of the activating body 20 in a predetermined angular position determines the switching of the state of the first sensor 9 (ie the switch 9).

[0031] This functionality is explained below with reference to the specific advantages of the innovation.

[0032] According to one aspect, the drive unit comprises a further spring 25 which is operatively coupled to the activation body 20 and the support body 4.

[0033] This additional spring 25 is active (inserted) between the activation body 20 and the support body 4. The functionality of this additional spring 25 is described in more detail below.

[0034] According to another aspect, the support body 4 comprises a housing seat 26 for the further spring 25, and one end of the further spring 25 is coupled to the activation body 20.

[0035] Preferably, the spring 25 is a linear spring.

[0036] The spring 25 is compressed between the first angular position of the activation body 20 (position corresponding to the non-tensioned or broken spring 7) and the second angular position of the activation body 20 (position corresponding to the tensioned spring 7).

[0037] According to another aspect, the drive unit comprises a second sensor 8 (preferably a switch) arranged in the support body 4 and designed to detect an actuation of the centrifugal brake 50 as a result of an exceeding of the angular rotation speed of the tubular body 2 corresponding to an excessive falling speed of the barrier with respect to a predetermined value.

[0038] This condition corresponds to the situation in which the spring 7 has broken due to a failure of the motor and / or the brake (or another mechanical component of the motor-barrier kinematic chain), resulting in a sudden acceleration (fall) of the barrier.

[0039] According to another aspect, the drive unit comprises a control unit connected to the first sensor 9 and / or the second sensor 8 and designed to trigger an alarm signal depending on a state of the signal received by the first sensor 9 and / or the second sensor 8.

[0040] According to another aspect, the drive unit comprises a reporting unit in communication with the control unit, which is designed to provide a report regarding the first sensor 9 and / or the second sensor 8.

[0041] Preferably, the first sensor 9 is defined by a switch. Furthermore, the second sensor 8 is preferably defined by a switch.

[0042] According to one aspect, the first and second switches 9, 8 each have a first and a second activation contact 9A, 8A.

[0043] Other aspects related to the drive unit are described below.

[0044] The support body 4 has a support section in which the seat 40 is arranged.

[0045] The support portion preferably has a square configuration and receives the seat 40.

[0046] The seat 40 is preferably defined by a hole in which the safety device 5 is accommodated.

[0047] The support section is preferably attached to the frame (not shown) of the rolling barrier when in use.

[0048] The centrifugal brake 50 comprises a first rotor portion 50A which, in use, is mechanically coupled to the motor 3 (preferably indirectly, ie, by means of other elements).

[0049] This first section 50A is set in rotation when the motor 3 is actuated.

[0050] The safety device 5 is designed to block rotation of the tubular body 2 under certain conditions (exceeding a predetermined rotation speed of the tubular body 2 corresponding to an excessive downward speed of the barrier wall), so that the falling of the rolling door is essentially stopped.

[0051] The safety device 5 is arranged at the end 2B of the tubular body 2.

[0052] The drive unit 1 according to the first embodiment also comprises a shaft 6 positioned inside the tubular body 2, having one end 6A mechanically coupled (in particular rotationally secured) to the inner surface 2C of the tubular body 2, and another end 6B coupled to the safety gear 5 (in particular to the first rotor portion 50A of the centrifugal brake 50).

[0053] According to the first embodiment, this shaft 6 thus enables the movement of the motor 3 to be transmitted to the first rotor section 50A of the centrifugal brake 50.

[0054] According to the first embodiment, the torsion spring 7 is arranged inside the tubular body 2.

[0055] According to the first embodiment, the torsion spring 7 is arranged so that it wraps around the shaft 6.

[0056] It should be noted that the torsion spring 7, the drop device 5 and the shaft 6 according to the first embodiment define a single assembly (aggregate) 100 due to the mechanical couplings.

[0057] The single assembly 100 is non-removably connectable to the tubular body 2.

[0058] Therefore, if the spring 7 breaks or if the safety device 5 is triggered, it is advantageously possible to replace the entire assembly 100.

[0059] As is well known, if the safety gear 5 is triggered, it must be replaced.

[0060] Regarding the second sensor 8, it should be noted that the second switch 8 is arranged in a first seat 4C of the support body 4. Preferably, the first switch 9 is attached to a region 4D on the support body 4.

[0061] In a preferred embodiment, the tubular body 2 has an octagonal cross-section.

[0062] The motor 3 comprises a rotor connected to the tubular body 2.

[0063] Motor 3 is a tubular motor.

[0064] Preferably, the motor 3 according to the first embodiment is united to the inner surface of the tubular body 2 by means of a flange 60.

[0065] Advantageously, such a drive unit allows to reduce the space requirement and is suitable for small areas such as in the case of roller shutters.

[0066] Advantageously, such a drive unit proves to be particularly practical during the assembly and installation phases.

[0067] In one aspect, the centrifugal brake 50 comprises a disc-shaped body 51 having (on its outer surface) a concave portion 52.

[0068] According to one aspect, the support body 4 comprises a locking portion 10, which is intended to contact (upon triggering of the centrifugal brake 50) some elements of the safety gear 5, in particular at least one stop element 30 of the disc-shaped body 51. According to one aspect, the disc-shaped body 51 comprises, as shown in Fig. 5 a first section 51A and a second section 51B.

[0069] In a preferred embodiment, the centrifugal brake 50 comprises a gear 27 which is accommodated within the disc-shaped body 51, in particular within the two sections 51A, 51B.

[0070] The gear 27 is defined by the rotor section 50A.

[0071] The wheel 27 has a plurality of recesses 52' and also has a central hole 53.

[0072] According to the first embodiment, the shaft 6 is coupled to the portion 50A of the safety gear 5 by means of the central hole 53.

[0073] The coupling by means of the hole 53 enables the transmission of a rotation of the shaft 6 to the section 50A of the safety gear 5 or to the gear 27.

[0074] The centrifugal brake 50 comprises a plurality of movable locking elements 54.

[0075] Each movable locking element 54 is housed at each recess 52' of the wheel 27.

[0076] In a preferred embodiment, which for example is shown in Fig. 11, the plurality of movable locking elements 54 includes ball elements 54'.

[0077] When the centrifugal brake 50 is activated, the ball elements 54' disposed in the recesses 52', in particular, emerge from the recesses 52' due to centrifugal force. In particular, the ball elements 54' are locked between the wheel 27 and the disc-shaped body 51, causing the disc-shaped body 51 to move due to the rotation of the wheel 27.

[0078] In this way, as described in more detail below, the centrifugal brake 50 of the safety gear 5 is triggered.

[0079] In one aspect, the disc-shaped body includes a first edge 51C that develops around at least a portion of the first section 51A.

[0080] According to one aspect, the support body 4 has a first stop portion 4B which is designed to strike the first edge 51C (or the stop element 30) upon actuation of the centrifugal brake 50.

[0081] In one embodiment, the disc-shaped body 51 is designed to rotate with respect to the support body 4 in a first direction of rotation W1 as a result of the actuation of the centrifugal brake 50.

[0082] In one embodiment, the first and second sensors (switches) 9, 8 are designed to generate a first signal as a result of the breakage of the torsion spring 7 and a second signal as a result of the actuation of the centrifugal brake 50.

[0083] As a result of the reception of the first and / or second signal, it is advantageously possible to interrupt the supply to the motor 3 and to secure the drive unit.

[0084] The release state of the centrifugal brake 50 and also the breakage state of the spring 7 are described in more detail below.

[0085] As already mentioned, the second switch 8 is designed to detect an actuation of the centrifugal brake 50 as a result of the barrier wall exceeding a predetermined fall value.

[0086] The following explains what happens in this condition, whereby the triggering of the centrifugal brake 50 maintains the mechanical integrity of the rolling door assembly and the safety of the users, thus acting as an active safety element in every respect.

[0087] It should be noted that the fact that the barrier exceeds a predetermined fall speed value is an exceptional event due to the failure of any electrical and / or mechanical components of the motor or the motor brake or other elements of the motor-barrier kinematic chain (e.g. the spring).

[0088] Under these circumstances, when the barrier wall accelerates downward, the rotor portion 50A of the centrifugal brake is also accelerated; as a result, the wheel 27 is accelerated and transmits a centrifugal acceleration to the rolling elements 54, which are pushed radially toward the radial periphery, ie, the inner wall, of the disc-shaped body 51.

[0089] The rolling elements 54 then engage radially circumferentially between the disc-shaped body 51 and the wheel 27, whereby the wheel 27 and the disc-shaped body 51 are firmly connected to one another in every respect in terms of rotation.

[0090] Due to the rotation of the wheel 27, which is actuated by the falling of the mobile wall, under these conditions the disc-shaped body 51 also rotates with respect to the support body 4.

[0091] The rotation of the disc-shaped body 51 with respect to the support body 4 causes the seat 52, on which the second switch 8 is active, to be displaced with respect to the support body 4 or with respect to the second sensor 8 (which is in a fixed position with respect to the support body 4).

[0092] Consequently, the slider 8A of the second switch 8 is no longer active in the seat 52, but in another peripheral zone of the disc-shaped body 51 (having a different radial height) and thus changes from one logical state (preferably "closed") to another logical state (preferably "open").

[0093] Switching the second switch 8 from the logical state “closed” to the logical state “open” enables the inhibition of the drive of the motor 3.

[0094] The second switch 8 is arranged in series in the circuit supplying the motor 3.

[0095] This second signal from the second switch 8 is therefore understandably a trigger signal from the centrifugal brake 50.

[0096] As regards the first sensor (switch) 9, it should be noted that it is designed to detect a breakage of the torsion spring 7 or a non-tensioned state of the spring 7.

[0097] In other words, the first switch 9 detects whether the torsion spring 7 is no longer in a state of tension (ie the storage of elastic energy).

[0098] As is known, the torsion spring 7 is compressed when the barrier wall moves from the opening position of the passage to the closing position of the passage and stores elastic energy.

[0099] The operating mechanism of the drive unit with respect to the first sensor 9 is as follows.

[0100] When the spring 7 is not tensioned, the further spring 25 maintains the activation body 20 in a predetermined angular position (first position) with respect to the support body 4.

[0101] This first angular position of the activation body 20 is in the Fig. 7 with reference to the first embodiment and in the Fig. 15 and Fig. 17 with reference to the second embodiment.

[0102] In this first angular position of the activation body 20, the first sensor (switch) 9 has a predetermined logical state (preferably “open”).

[0103] The first sensor 9, in particular the activation slide 9A of the switch 9, is operatively connected to a first zone 29A ( Fig. 10) of the activation body 20 is active.

[0104] Under these circumstances, the first sensor 9 can advantageously be used to provide a spring 7 “not tensioned” signal that can be used by the technicians during the installation / assembly phase.

[0105] As a result of the rotation of the motor 3 (in the direction indicated by W1), the rotational movement of the motor 3 is transmitted to the end 7A (distal to the centrifugal brake 50 and proximal to the motor 3) of the spring 7. The rotation of the end 7A (distal to the centrifugal brake 50 and proximal to the motor 3) of the spring 7 pulls the activation body 20 in rotation until its angular stop position, i.e., into a second angular position (position defined by the relative dimensions of the projections 23B and recesses 23A).

[0106] This second angular position of the activation body 20 is in the Fig. 6 with reference to the first embodiment and in the Fig. 16 and Fig.18 with reference to the second embodiment. Starting from this second angular position of the activation body 20, further rotation of the motor 3 (in the direction designated W1) causes the tensioning of the spring 7, i.e., the storage of elastic energy in the spring 7.

[0107] In this second angular position of the activation body 20, the further spring 25 is compressed.

[0108] It should be noted that without external forces acting on the activation body 20, the spring 25 tends to push the activation body 20 from the second angular position to the first angular position.

[0109] It should also be noted that the logical state of the first sensor 8 (logical state “closing”) in this second angular position of the activation body 20 differs from that of the first position (logical state “opening”).

[0110] If the spring 7 breaks, the activation body 20 has no fastening of the spring 7 and can thus rotate freely from the first angular position to the second angular position.

[0111] Since the further spring 25 is compressed, when the spring 7 breaks, the stored elastic energy is released and causes the activation body 20 to rotate from the second position to the first position.

[0112] As a result of the displacement of the activation body 20, the first sensor 9 is therefore able to switch the logical state.

[0113] According to the concept underlying the invention, this causes the first sensor 9 to switch from one logical state to another.

[0114] This switching of the first sensor 9 corresponds to a break signal of the spring 7.

[0115] Some differences between the first embodiment (already described above) and the second embodiment (which is now introduced) are described below, particularly with regard to the mounting of the barrier wall and the transmission of movement from the motor 3 to the centrifugal brake 50 and the spring 7. In this second embodiment, the spring 7 is mounted externally on the tubular body 2.

[0116] In this case, the drive unit comprises external bushings 32 which are rotated by the rotor 3.

[0117] The barrier wall is attached to these sockets 32.

[0118] These bushings 32 absorb the movement of the tubular body 2 directly or via elements inserted therebetween.

[0119] The drive unit also includes a bushing 80 which is free-running, ie not driven by the motor 3.

[0120] According to this second embodiment, one end 7B of the spring is attached directly to the activation body 20.

[0121] According to this second embodiment, the activation body 20 is provided with limiting recesses 23A, and the support body 4 comprises projections 23B defined by screws and / or sleeves wedged on screws, which engage with a clearance in the recesses 23A.

[0122] It should be noted that the clearance nature of the recesses 23A with respect to the projections 23B allows the activation body 20 to rotate relative to the support body 4. It should be noted that the second embodiment is essentially equivalent to the first embodiment in terms of the operating principle with respect to the first sensor 9 or the second sensor 8.

[0123] The drive unit according to the second embodiment does not have a shaft 6: the movement on the bushings 32 is transmitted by the tubular body 2 (by means of a positive coupling allowing the transmission of the torsional moment) or by elements inserted between the tubular body 2 and the bushings 32 and allowing the transmission of the rotary movement.

Claims

[1] Drive unit of a rolling barrier, comprising: - a tubular body (2) having a main development direction (D) and a first and a second end (2A, 2B); - a motor (3) designed to rotate the tubular body (2); - a support body (4) having an accommodation seat (40); - a safety device (5) housed in the seat (40) of the support body (4) and comprising a centrifugal brake (50) operatively coupled to the tubular body (2) in use, the safety device (5) being designed to engage when a predetermined rotational speed of the tubular body (2) is exceeded and to block rotation of the tubular body (2); - at least one torsion spring (7) having a first end (7A) coupled to the motor (3) to be set in rotation; - a first sensor (9) designed to detect a signal relating to a state of the torsion spring (7). [2] Drive unit according to the preceding claim, wherein the first sensor (9) is associated with the support body (4), in particular is fastened thereto. [3] Drive unit according to the preceding claim, comprising a second sensor (8) arranged in the support body (4) and designed to detect an actuation of the centrifugal brake (50). [4] Drive unit according to one of the preceding claims, comprising: - an activation body (20) which is partially rotatable with respect to the support body (4), wherein - the torsion spring (7) also has a second end (7B) opposite the first end (7A) and operatively connected directly or indirectly to the activation body (20); - the first sensor (9) is designed to switch as a result of a rotation of the activation disc (20). [5] Drive unit according to the preceding claim, wherein the activation body (20) is designed to rotate with respect to the support body (4) by an angle of less than 45°. [6] Drive unit according to one of the preceding claims 4 or 5, wherein the activation body (20) comprises a housing seat (21) and wherein the second end (7B) is fixed to the activation body (20) inserted into the housing seat (21). [7] Drive unit according to one of the preceding claims 4 or 5, wherein the activation body (20) has the shape of a disc. [8] Drive unit according to one of the preceding claims 4 or 5 or 6, comprising a body (22) for fastening the spring (7), to which the second end (7B) of the spring (7) is fastened, and wherein the activation body (20) is coupled to the fastening body (22). [9] Drive unit according to one of the preceding claims 4 to 8, wherein either the activation body (20) or the support body (4) comprises limiting recesses (23A), and the other element, either the support body (4) or the activation body (20), comprises projections (23B) designed to fit into the recesses (23A), wherein the limiting recesses (23) and projections (23B) are designed to define limitations on the partial rotation of the activation body (20) with respect to the support body (4). [10] Drive unit according to one of the preceding claims 4 to 9, wherein the activation body (20) has an activation projection (24A) or an activation recess designed to engage with the first sensor (9) when the activation body (20) is in a predetermined angular position with respect to the support body (4). [11] Drive unit according to one of the preceding claims 4 to 10, comprising a further spring (25) which is operatively coupled to the activation body (20) and the support body (4). [12] Drive unit according to the preceding claim, wherein the support body (4) comprises a housing seat (26) for the further spring (25) and wherein one end of the further spring (25) is coupled to the activation body (20). [13] Drive unit according to one of the preceding claims 11 or 12, wherein the spring (25) is a linear spring. [14] Drive unit according to one of the preceding claims, comprising a second sensor (8) arranged in the support body (4) and designed to detect an actuation of the centrifugal brake (50) as a result of the falling speed of the barrier wall being exceeded with respect to a predetermined value. [15] Drive unit according to one of the preceding claims, comprising a control unit which is connected to the first sensor (9) and is designed to trigger an alarm signal depending on a state of the signal received by the first sensor (9). [16] Drive unit according to claim 15, comprising a reporting unit in communication with the control unit, which is designed to provide a report regarding the first sensor (9) and / or the second sensor (8). [17] Drive unit according to one of the preceding claims, wherein the motor (3) comprises a rotor which is connected to the tubular body (2). [18] Drive unit according to one of the preceding claims, wherein the support body (4) comprises a locking portion (10) which is intended to contact the safety device (5) upon actuation of the centrifugal brake (50). [19] Drive unit according to one of the preceding claims, wherein the centrifugal brake (50) comprises a disc-shaped body (51). [20] Drive unit according to one of the preceding claims and claim 19, wherein the disc-shaped body (51) has a concave portion (52). [21] Drive unit according to one of the preceding claims and claims 3 and 20, wherein the second sensor (8) is in contact with the concave portion (52) when the centrifugal brake (50) is not actuated. [22] Drive unit according to one of the preceding claims 19 to 21, wherein the disc-shaped body (51) comprises a first portion (51A) and a second portion (51B). [23] Power unit according to the preceding claim, wherein the disc-shaped body (51) comprises a first edge (51C) which develops at least around the first portion (51A). [24] Drive unit according to the preceding claim, wherein the support body (4) has a first stop portion (4B) which is designed to potentially strike the first edge (51C) upon actuation of the centrifugal brake (50). [25] A drive assembly according to any one of claims 19 to 24, wherein the disc-shaped body (51) comprises a second edge (51D) extending around at least the second portion (51B). [26] Drive unit according to the preceding section, wherein the support body (4) has a second stop portion (4A) designed to abut the second edge (51D). [27] A drive assembly according to any one of the preceding claims and claim 19, wherein the centrifugal brake (50) comprises a gear (27) received within the disc-shaped body (51) and having a plurality of recesses (52') and a central hole (53). [28] Drive unit according to the preceding claim, wherein the centrifugal brake (50) comprises a plurality of movable locking elements (54), each movable locking element (54) being received in a recess (52') of the gear (27). [29] Drive unit according to claim 28, wherein the plurality of movable locking elements (54) comprise ball elements (54') or cylinder elements. [30] Drive unit according to one of the preceding claims, wherein the safety device (5) is designed to rotate with respect to the support body (4) in a first direction of rotation (W1) as a result of the actuation of the centrifugal brake (50). [31] Drive unit according to one of the preceding claims, wherein the tubular body (2) has an octagonal cross-section. [32] Drive unit according to one of the preceding claims, wherein the tubular body (2) has a cylindrical cross-section. [33] Drive unit according to one of the preceding claims, wherein the first sensor (9) is designed to generate a first signal as a result of the breakage of the torsion spring (7). [34] Drive unit according to one of the preceding claims, wherein the first sensor (9) is defined by a switch. [35] Drive unit according to one of the preceding claims and claim 3, wherein the second sensor (8) is defined by a switch.

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