Electromagnetic brake for motor drives of roller shutters and motor drive for roller shutters comprising such electromagnetic brake

Abstract

Electromagnetic brake (1) for motor drives (20) configured to rotate drive shafts of roller shutters, which electromagnetic brake (1) comprises a core (4) made of ferromagnetic material, a copper wire coil (5) arranged on the core (4) so as to form an assembly (7), the coil (5) being intended to generate electromagnetic fields by means of the electric power supply, a covering casing (6) with a respective cap (2), means (8) for coupling the cap (2) together with the assembly (7), a disc (10) intended to be moved between an active configuration, in which it is in contact with the body of an electric motor (22) of a motor drive (20) so as to prevent rotation of a drive shaft, and a passive configuration, in which it is spaced from the body of the electric motor (22) so as to allow rotation of the drive shaft, and a spring (9) arranged between the assembly (7) and the disc (10). The disc (10) is kept in the active configuration by the spring (9) and is moved into the passive configuration by means of the electromagnetic attraction effect due to the electromagnetic fields generated by the electrically powered coil (5). The coupling means (8) comprise at least one spring washer (8A) and a Seeger ring (8B).

Description

[0001] “Electromagnetic brake for motor drives of roller shutters and motor drive for roller shutters comprising such electromagnetic brake”

[0002] ★ ★★★★

[0003] Field of application

[0004] The present invention falls within the technical sector of motor drives for roller shutters, said drives comprising in particular electric motors and respective electromagnetic brakes.

[0005] Prior art

[0006] As known from the prior art, roller shutters are mounted in openings designed to connect an internal environment, such as a room in a house, with the external environment; the roller shutters make it possible to selectively prevent access and communication through said openings.

[0007] Generally, a roller shutter is intended to be wound up onto a horizontal shaft which supports respective idle rollers, the shaft being rotatable about a respective longitudinal axis.

[0008] The shaft is connected to an electric motor, in particular an electric gearmotor, and is intended to be rotated by the electric motor; generally, the motor is mounted suspended from the shaft.

[0009] Operation of the motor allows the roller shutter to be wound up and unwound so as to move it between a closed position, in which the shutter is unwound from the shaft, and an open position, in which the shutter is almost completely wound up onto the shaft.

[0010] During the movement, the roller shutter exerts a resistive torque which is variable depending, for example, on its weight, the friction or the external atmospheric agents, this resistive torque opposing the movement imparted by the electric motor.

[0011] The electric motor also comprises an electromagnetic brake which is able to selectively block the roller shutter at any height between the closed position and the open position for safety reasons.

[0012] In particular, the electromagnetic brake prevents the unintentional unwinding and therefore sudden lowering of the roller shutter and also manual raising and / or raising from the outside of the roller shutter when it is in the closed position.

[0013] The electromagnetic brake comprises mainly a plate or disc and a spring; when the motor is not electrically powered, the disc of the electromagnetic brake is kept pressed against the motor body as a result of the thrusting action of the spring, so as to prevent free rotation of the shaft connected to the motor.

[0014] During the movement of the roller shutter, and therefore when the motor is electrically powered, the disc is separated and moved away from the motor body, so as to allow the rotation of the shaft.

[0015] The separation and movement away of the disc are performed by means of electromagnetic fields generated by a copper wire coil arranged on a core made of ferromagnetic material, which also forms part of the electromagnetic brake.

[0016] In particular, the electromagnetic attraction of the coil allows the disc to be moved away from the body of the electric motor, overcoming the resistance of the spring.

[0017] Should there be no electric power, it is possible to move the roller shutter manually by releasing firstly the electromagnetic brake by means of a manual release device, which generally comprises a cable intended to be pulled by the user.

[0018] As can be seen in Figure 1 , which shows an embodiment in accordance with the prior art, the electromagnetic brake 101 also comprises a cap 102 made of aluminium or other similar material.

[0019] A C-shaped bracket 103 made of ferromagnetic material and the above-described core 104 are contained inside the cap 102, the spring 109 being suitably positioned between the C-shaped bracket 103 and the disc 110. Moreover, the core 104 and the C-shaped bracket are arranged inside the cap 102 with an intermediate support element 111 , also visible in Figure 1 , arranged in between them.

[0020] The coil 105 is fixed to the bracket 103 by means of a Seeger ring 106 so as to form a single assembly 107, said assembly 107 being secured to the cap 102 by means of two fixing screws 108 intended to be inserted inside threaded through-holes 113 provided on an end surface of the cap 102 and on a transverse section of the C- shaped bracket 103.

[0021] A first drawback of the aforementioned technical solution consists in the fact that the production of the C-shaped bracket 103 is performed by mean of a progressive die cutting process, a low-cost technology which however results in tolerance errors of about ±1 / 10. Alternatively, the production may also be performed by means of further bending processes, for example using a bending press.

[0022] These tolerance errors may result in malfunctioning of the electromagnetic brake owing to an excessive or insufficient air gap.

[0023] In order to overcome at least partially this drawback, the operator may perform manual adjustments of the fixing screws 108, tightening or loosening them depending on the tolerance error detected, during assembly of the roller shutter with the corresponding electric motor.

[0024] This adjustment procedure has the drawback that it requires particularly long assembly times and results in the need for the operator to perform manual adjustment operations in order to ensure correct operation of the electromagnetic brake 101 .

[0025] A further drawback consists in the fact that the C-shaped bracket 103 and the core 104 must be pre-assembled by a supplier before definitive assembly of the electromagnetic brake, resulting in further costs. Presentation of the invention

[0026] The main object of the present invention is to overcome the drawbacks of the prior art described above by providing an electromagnetic brake for motor drives of roller shutters and a motor drive for roller shutters comprising such electromagnetic brake, which are able to solve the aforementioned drawbacks.

[0027] A further object of the present invention is to provide an electromagnetic brake of the type described above which is able to simplify the motor drive and the roller shutter assembly operations.

[0028] Another object of the present invention is to provide an electromagnetic brake of the type described above which allows the motor drive and the roller shutter assembly operations to be performed more rapidly.

[0029] A further object of the present invention is to provide an electromagnetic brake of the type described above which is able to avoid or limit the manual adjustment operations performed by an operator.

[0030] Another object of the present invention is to provide an electromagnetic brake of the abovementioned type which is able to improve the negative braking efficiency of the motor drive.

[0031] The object and the main tasks described above are achieved with an electromagnetic brake according to Claim 1 and a motor drive for roller shutters according to Claim 10.

[0032] Brief description of the drawings

[0033] In order to illustrate more clearly the innovative principles of the present invention and its advantages compared to the prior art, an example of embodiment of an electromagnetic brake according to the prior art and an electromagnetic brake and a motor drive according to the present invention will be described below with the aid of the attached figures. In particular: - Figure 1 is an exploded perspective view of an electromagnetic brake according to the prior art;

[0034] - Figure 2 is a perspective view of a motor drive with an electromagnetic brake according to the present invention;

[0035] - Figure 3 is a perspective view of an electromagnetic brake according to the present invention in the assembled configuration;

[0036] - Figure 4 is an exploded perspective view of the electromagnetic brake according to the present invention.

[0037] Detailed description

[0038] The present invention relates to an electromagnetic brake for motor drives configured to rotate drive shafts of roller shutters and a motor drive for roller shutters comprising such an electromagnetic brake.

[0039] The electromagnetic brake is denoted overall by the reference number 1 and the motor drive is denoted overall by the reference number 20.

[0040] Furthermore, the motor drive 20 according to the present invention is shown in detail in Figure 2 and the electromagnetic brake 1 according to the present invention is illustrated in detail in Figures 3 and 4.

[0041] In a manner known per se, the motor drive 20 comprises, in addition to the electromagnetic brake 1 according to the present invention, an electric motor 22, in particular an electric gearmotor, intended to be electrically powered and a drive shaft which is connected to the electric motor and on which a roller shutter is wound.

[0042] The drive shaft is rotated by the electrically powered motor 22 so as to be rotatable about a longitudinal axis X and to move the roller shutter between a closed position, in which the shutter is unwound from the drive shaft, and an open position, in which the shutter is at least partially or almost fully wound onto the drive shaft.

[0043] The roller shutter is not shown in the attached figures and the drive shaft is not visible in the attached figures. The electric motor 22 is of the known type and will not be further described in the continuation of the present description.

[0044] Moreover, as illustrated more clearly in Figure 2, the motor drive 20 comprises a cable 24 connected to the electromagnetic brake 1 and designed to be pulled by a user for manual release of the electromagnetic brake 1 in the event of an interruption in the electric power supply.

[0045] The cable 24 is also of the type known per se and will not be further illustrated in detail in the continuation of the present description.

[0046] The electromagnetic brake 1 preferably comprises:

[0047] - a core 4 made of ferromagnetic material;

[0048] - a copper wire coil 5 arranged on the core 4 so as to form an assembly 7, the coil 5 being intended to generate electromagnetic fields by means of the electric power supply;

[0049] - a covering casing 6 with a respective cap 2;

[0050] - means 8 for coupling the cap 2 together with the assembly 7 formed by the core 4 and the coil 5;

[0051] - a disc 10 intended to be moved between an active configuration, in which it is in contact with the body of the electric motor 22 of the motor drive 20 so as to prevent rotation of the drive shaft, and a passive configuration, in which it is spaced from the body of the electric motor 22 so as to allow rotation of the drive shaft;

[0052] - a spring 9 arranged between the assembly 7 and the disc 10.

[0053] The disc 10 is kept in the active configuration by the spring 9 and is moved into the passive configuration by means of the electromagnetic attraction effect due to the electromagnetic fields generated by the electrically powered coil 5.

[0054] In the aforementioned passive configuration, the electromagnetic attraction of the coil 5 is able to overcome the resistance of the spring 9, moving the disc 10 away from the body of the electric motor 22 and allowing the drive shaft to rotate about the longitudinal axis X in order to move the roller shutter.

[0055] The selective activation of the coil 5 may be remotely performed by an operator via a control device, of the type known per se and not further described in the present description.

[0056] In accordance with a particular aspect of the invention, the coupling means 8 comprise at least one spring washer 8A and a Seeger ring 8B, as illustrated more clearly in Figure 4.

[0057] Advantageously, the spring washer 8A and the Seeger ring 8B are inserted and locked onto a portion 11 of the core 4 projecting from an end surface 12 of the cap 2. In particular, said portion 11 of the core 4 projects at least partially through a through-hole 13 formed in the end surface 12 of the cap 2 and having a shape matching that of the portion 11 of the core 4.

[0058] The cable 24 for manual release of the electromagnetic brake 1 is also connected to the projecting portion 11 of the core 4 by means of a suitable connector 26, as shown in Figures 2 and 3.

[0059] As is more clearly visible in Figure 4, the core 4 comprises a further portion 14 integral with the projecting portion 11 and having a main body 14A and a respective end surface 14B.

[0060] Conveniently, the main body 14A of the further portion 14 of the core 4 is inserted and housed inside a passage 15 formed in the coil 5.

[0061] Moreover, the end surface 14B of the further portion 14 faces the disc 10 and is designed to come into contact with the disc 10. For this purpose, the end surface 14B is larger in size than the diameter of the main body 14A.

[0062] This latter feature results in an improvement in the electromagnetic field generation efficiency for the same amount of electric power used. The electromagnetic brake 1 also comprises a C-shaped bracket 3 for supporting the assembly 7 formed by the core 4 and the coil 5 and an intermediate support element 17.

[0063] The bracket 3 is arranged between the assembly 7 and the inner surface of the cap 2 and the intermediate element 17 is arranged between the bracket 3 and the inner surface of the cap 2.

[0064] In a manner known per se, the C-shaped bracket 3 is made by means of a progressive die cutting process. Alternatively, the C-shaped bracket 3 may also be made by means of further bending processes.

[0065] Conveniently, the C-shaped bracket 3 of the present invention is also displaceable, about one or two tenths of a millimetre, along the longitudinal axis X in order to move the assembly 7 towards the disc 10.

[0066] The use of the coupling means 8 described above and the possibility of axial displacement of the C-shaped bracket 3 allows automatic adjustment of the electromagnetic brake 1 during operation, with the assembly 7 being automatically moved towards the disc 10 and with compensation of the production tolerances of the C-shaped bracket 3 due to the progressive die cutting process.

[0067] Conveniently, the C-shaped bracket 3 also has a through-hole 16 for inserting and housing the projecting portion 11 of the core 4.

[0068] In particular, this through-hole 16 is formed in a transverse section 3A of the C- shaped bracket 3 facing the inner surface of the cap 2 and aligned with the intermediate support element 17 and with the through-hole 13 formed in the end surface 12 of the cap 2.

[0069] Differently from the electromagnetic brakes known from the prior art, the assembly 7 formed by the core 4 and the coil 5 is removably coupled together with the C-shaped bracket 3. Therefore, the assembly 7 and the C-shaped bracket 3 are no longer provided preassembled before mounting of the electromagnetic brake, thus allowing the production costs to be reduced.

[0070] Conveniently, the C-shaped bracket 3, as well as the core 4, is made of ferromagnetic material, the cap 2 is made of aluminium or a similar material and the spring washer 8A is made of spring steel.

[0071] From the above description it is now clear how the electromagnetic brake and the motor drive according to the present invention are able to achieve advantageously the predefined objects.

[0072] In particular, the above-described configuration of the electromagnetic brake is able to simplify the motor drive and the roller shutter assembly operations and allow said motor drive and the roller shutter assembly operations to be performed more rapidly. Moreover, with the electromagnetic brake of the type described above it is possible to avoid the manual adjustment operations performed by an operator and the braking efficiency is improved.

[0073] Obviously, the above description of embodiments applying the innovative principles of the present invention is provided by way of example of these innovative principles and must therefore not be regarded as limiting the scope of the rights claimed herein.

Claims

Claims1. Electromagnetic brake (1 ) for motor drives (20) configured to rotate drive shafts of roller shutters, which electromagnetic brake (1 ) comprises:- a core (4) made of ferromagnetic material;- a copper wire coil (5) arranged on said core (4) so as to form an assembly (7), said coil (5) being intended to generate electromagnetic fields by means of the electric power supply;- a covering casing (6) with a respective cap (2);- coupling means (8) for coupling said cap (2) together with said assembly (7);- a disc (10) intended to be moved between an active configuration, in which the disc is in contact with the body of an electric motor (22) of a motor drive (20) so as to prevent rotation of a drive shaft, and a passive configuration, in which the disc is spaced from the body of the electric motor (22) so as to allow rotation of the drive shaft;- a spring (9) arranged between said assembly (7) and said disc (10); wherein said disc (10) is kept in the active configuration by said spring (9) and is moved into said passive configuration by means of the electromagnetic attraction effect due to the electromagnetic fields generated by said electrically powered coil (5); characterized in that the coupling means (8) comprise at least one spring washer (8A) and a Seeger ring (8B).

2. Electromagnetic brake (1 ) according to claim 1 , characterized in that said spring washer (8A) and said Seeger ring (8B) are inserted and locked on a portion (11 ) of said core (4) projecting from an end surface (12) of said cap (2).

3. Electromagnetic brake (1 ) according to any one of the preceding claims, characterized in that the electromagnetic brake comprises a C-shaped bracket (3)arranged between said assembly (7) and the inner surface of said cap (2) for supporting said assembly (7) formed by the core (4) and by the coil (5), said bracket(3) being displaceable along a longitudinal axis (X) so as to move the assembly (7) towards the disc (10).

4. Electromagnetic brake (1 ) according to the preceding claim when dependent on claim 2, characterized in that said C-shaped bracket (3) has a through-hole (16) for inserting and housing said projecting portion (11 ) of the core(4).

5. Electromagnetic brake (1 ) according to claim 3, characterized in that said C-shaped bracket (3) is made by means of a progressive die cutting process.

6. Electromagnetic brake (1 ) according to any one of claims 3-5, characterized in that said assembly (7) is removably coupled with said C-shaped bracket (3).

7. Electromagnetic brake (1 ) according to claim 2, characterized in that said core (4) comprises a further portion (14) integral with said projecting portion (11 ) and having a main body (14A) and an end surface (14B) larger in size than said main body (14A), said end surface (14A) facing said disc (10) and being designed to come into contact with said disc (10).

8. Electromagnetic brake (1 ) according to the preceding claim, characterized in that the main body (14A) of the further portion (14) of said core (4) is inserted and housed inside a passage (15) formed in said coil (5).

9. Electromagnetic brake (1 ) according to any one of the preceding claims, characterized in that said spring washer (8A) is made of spring steel.

10. Motor drive (20) for roller shutters, comprising:- an electric motor (22) intended to be electrically powered;- a drive shaft which is connected to said electric motor (22) and around whicha roller shutter is wound, said drive shaft being rotated about a longitudinal axis (X) by said electric motor (22) so as to move the roller shutter between a closed position, in which the shutter is unwound from the drive shaft, and an open position, in which the shutter is at least partially wound onto the drive shaft.- an electromagnetic brake (1 ) associated with said electric motor (22); characterized in that said electromagnetic motor (1 ) is of the type according to any one of Claims 1 to 9.

11. Motor drive (20) according to the preceding claim, characterized in that the motor drive comprises a cable (24) for the manual release of the electromagnetic brake (1 ).

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