FIELD

[01 ] This invention relates to a roller shutter door assembly, a kit of parts for a roller shutter door and a fail-safe method of operating a roller shutter door.

BACKGROUND

[02] Doors which act as fire doors must comply with relevant product standards, in order to operate in a safe manner in the event of a fire. For example, BS EN 14637:2007 sets out the European standard for electrically operated hold-open systems for fire doors. According to the standard, hold-open systems must disengage in the event of a fire or fault, allowing the door to close. In the case of traditional hinged doors, the hold-open system disengages and releases stored mechanical energy (e.g. in springs), closing the door and allowing it to act as a barrier to fire.

[03] Roller shutter doors typically comprise an assembly of laths that can be stored on a rotatable barrel above a doorway. The rotatable barrel is turned to lower the assembly of laths to cover the doorway. The laths are hinged together to allow for movement between the rolled configuration and a deployed configuration covering the doorway. The rotatable barrel is typically driven by a motor. In a typical roller shutter assembly, the motor has an integral brake, which activates when there is no power to the motor, in order to retain the door in position.

[04] It is an aim of the invention to provide a roller shutter door assembly which may safely act as a fire door, preferably in compliance with the relevant product standards.

SUMMARY

[05] According to the present invention there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

[06] According to a first aspect of the disclosure there is provided a roller shutter door assembly, comprising: a rotatable barrel; a roller shutter door connected to the rotatable barrel; a motor configured to drive the rotatable barrel to open or close the roller shutter door; and a braking system configured to apply a braking force to the barrel to prevent rotation thereof upon receipt of power and release the braking force in response to loss of power.

[07] The motor may have an active state in which it is configured to drive the rotatable barrel to open or close the roller shutter door. The motor may have an inactive state in which it is configured to permit rotation of the barrel. The braking system may be configured to apply the braking force when the motor is in the inactive state.

[08] The motor may be a tubular motor, suitably disposed within the barrel. The motor may be disposed remotely from the barrel and connected to the barrel by a drive connection.

[09] The braking system may comprise a brake disc mounted to the rotatable barrel. The braking system may comprise a braking unit configured to apply a friction force to the brake disc to prevent rotation thereof.

[10] The braking unit may comprise a brake calliper arranged to apply a compressive force to an edge portion of the brake disc.

[11] The braking unit may be configured to apply the friction force to a face of the brake disc.

[12] The braking unit may be mounted on a torque arm.

[13] The braking system may be a concentric braking system, arranged radially around a shaft rotationally fixed to the barrel. The shaft may be a mounting shaft, rotationally supportable by a mounting bracket. The concentric braking system may comprise a coil housing comprising an electromagnetic coil, a hub rotationally fixed to the shaft, and an armature connected to the hub and movable from a first position in which there is an air gap between the armature and the coil housing, and a second position in which the armature contacts the coil housing to apply the braking force, upon supply of power to the braking system. The braking system may comprise a biasing member to bias the armature to the first position upon loss of power.

[14] The roller shutter door may be configured to close upon release of the braking force. The roller shutter door may be weighted to overcome a gearing system connecting the motor and the barrel. The roller shutter door may be a fire door.

[15] According to a second aspect of the disclosure, there is provided a control unit for a roller shutter door assembly as defined in the first aspect, the control unit configured to: receive power from a first power supply, supply power to the motor of the roller shutter door assembly and cease power supply to the braking system to move the roller shutter door; and supply power to the braking system of the roller shutter door assembly to hold the roller shutter door in position.

[16] The control unit may be configured to communicate with a fire and/or smoke detection system. The control unit may be configured to cease power supply to the braking system upon activation of the fire and/or smoke detection system.

[17] The control unit may be configured to detect a fault in the fire and/or smoke detection system, motor or braking system, and in response cease power supply to the braking system. [18] The first power supply may be a mains power supply. The control unit may be configured to receive power from a second power supply, which may be a battery power supply. The control unit may be configured to supply power to the braking system from the second power supply, in response to a fault in the first power supply, suitably for a predetermined time period.

[19] The control unit may be configured to supply a first level of power to activate the braking system to apply the braking force. The control unit may be configured to apply a second level of power to maintain application of the braking force. The second level of power may be lower than the first level of power.

[20] Further suitable features of the control unit of the second aspect are defined herein with respect to the first aspect, and may be combined in any combination. In addition, the roller shutter door assembly of the first aspect may comprise the control unit of the second aspect.

[21] According to a third aspect of the disclosure, there is provided a kit of parts for a roller shutter door assembly, comprising: a motor configured to drive a rotatable barrel to open or close a roller shutter door, and a braking system configured to: apply a braking force to the barrel to prevent rotation thereof upon receipt of power; and release the braking force in response to loss of power.

[22] The kit may comprise a control unit as defined in the second aspect.

[23] Further suitable features of the kit of parts of the third aspect are defined herein with respect to the first and second aspects, and may be combined in any combination.

[24] According to a fourth aspect of the disclosure, there is provided a fail-safe method of operating a roller shutter door, comprising: applying a braking force to prevent rotation of a barrel of the roller shutter door; and releasing the braking force in response to detection of a fail-safe condition.

[25] Further suitable features of the method of the fourth aspect are defined herein with respect to the first, second and third aspects, and may be combined in any combination.

BRIEF DESCRIPTION OF DRAWINGS

[26] For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example only, to the accompanying diagrammatic drawings in which:

[27] FIG. 1 is a schematic perspective view of a roller shutter door shown between open and closed configurations;

[28] FIG. 2 is a schematic block diagram of a first example roller shutter door assembly; [29] FIG. 3 is a schematic side view of a first example roller shutter door assembly, with the roller shutter door omitted;

[30] FIG. 4A is a schematic side view of a second example roller shutter door assembly with the roller shutter door omitted;

[31] FIG. 4B is a schematic cross-sectional side view showing the braking system of the example roller shutter door assembly of FIG. 4A with the braking system released;

[32] FIG. 4C is a schematic cross-sectional side view showing the braking system of the example roller shutter door assembly of FIG. 4A with the braking system applying a braking force;

[33] FIG. 5A is a schematic side view of a third example roller shutter door assembly;

[34] FIG. 5B is an enlarged schematic side view of the braking system of the example roller shutter door assembly of FIG. 5A and

[35] FIG. 6 is a flowchart of an example fail-safe method of operating a roller shutter door.

[36] In the drawings, corresponding reference characters indicate corresponding components. The skilled person will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various example embodiments. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various example embodiments.

DESCRIPTION OF EMBODIMENTS

[37] In overview, examples of the disclosure relate to a roller shutter door assembly that, upon a power cut, malfunction or receipt of a fire alarm signal, releases a brake holding the door. This prevents the door being held open in the event of a fire, and may allow the door to return to a closed configuration.

[38] FIG. 1 shows an example roller shutter door 10. The roller shutter door 10 comprises a plurality of horizontally oriented laths 11 , and is mounted on a rotatable barrel 12 above a doorway opening 13. A motor 14 (see FIG. 2 and 3) is configured to rotate the barrel 12 to cause the roller shutter door 10 to move between an open configuration in which the roller shutter door 10 is rolled around the barrel 12, and a closed or deployed configuration in which the roller shutter door 10 covers the doorway opening.

[39] FIG. 2 and 3 show an example roller shutter door assembly 1. The roller shutter door assembly 1 comprises the roller shutter door 10, the barrel 12, and the motor 14. In addition, the assembly 1 comprises a braking system 16.

[40] The barrel 12 is rotatably mounted. A first end of the barrel may comprise a shaft 12a, configured to be supported by a suitable mounting bracket (not shown). For example, the mounting bracket may be a plate having an aperture comprising bearings to rotatably support the shaft.

[41] The motor 14 is operatively connected to the barrel 12, such that rotation of the axle of the motor 14 causes rotation of the barrel 12. For example, the motor 14 may be a tubular motor 14, which is be disposed at least partially within the barrel 12. The components shown in dashed lines in FIG. 3 are disposed in the interior of the barrel 12. The motor 14 comprises a motor head 14a, which protrudes from a second end of the barrel 12 opposite the first end, and which may be secured to a suitable mounting bracket (not shown) in order to rotationally support the second end of the barrel 12. The motor 14 may be connected to a driven wheel 12c disposed within the barrel. Upon activation, the motor 14 may deliver drive to the driven wheel 12c by virtue of a suitable gearing assembly (not shown), which may for example gear down the rotation of the axle of the motor 14. The motor 14 is configured such that the axle may be driven to rotate in either direction, so as to open and close the roller shutter door 10.

[42] The motor 14 is configured such that its axle may freely rotate when the motor 14 is not being driven. In other words, the motor 14 has no integral brake to prevent rotation of the axle. When the motor 14 is being driven, the motor 14 may be referred to herein as being in an active state. When the motor 14 is not being driven, the motor 14 may be referred to herein as being in an inactive state.

[43] The braking system 16 comprises a brake disk 18 and a braking unit 20. The brake disc 18 may be formed at one end of the barrel 14, and is rotationally fixed therewith. The braking unit 20 takes the form of a brake calliper, arranged at a rim of the disc 18. The calliper receives a portion of the disc 18, and once activated, is configured to apply a compressive force to the disc 18 to prevent rotation thereof.

[44] The braking system 16 is configured to activate upon receipt of power, for example DC power of 12 or 24 volts. Upon loss of power, the braking system 16 is configured to deactivate, thereby permitting rotation of the disc 18, and thus the barrel 12.

[45] As illustrated in FIG. 2, the roller shutter assembly 1 further comprises a control unit 30, which is configured to control the operation of the assembly 1. The control unit 30 may be a separate unit disposed remotely from the roller shutter assembly 1 or may alternatively be disposed in a housing of the roller shutter assembly 1.

[46] The control unit 30 is configured to receive power from a power supply 2, which may for example be a mains power supply. The control unit 30 is configured to selectively control the supply of power to the motor 14 from the power supply 2, so as to selectively activate and deactivate the motor 14.

[47] The control unit 30 is also configured to selectively control the supply of power to the braking system 16, so as to activate and deactivate the braking system 16. [48] The control unit 30 may also be configured to monitor the motor 14 and/or braking system 16, so as to detect a fault therein.

[49] The control unit 30 may also be connected to a battery power supply 4. The battery power supply 4 may act as a back-up power supply in the event of the failure or interruption of the power supply 2, as will be discussed in more detail below.

[50] The control unit 30 may also be configured to communicate with a fire and/or smoke detection system 5. The control unit 30 may be configured to actively monitor the fire and/or smoke detection system 5 in order to determine if the detection system 5 activates or develops a fault. In other examples, the control unit 30 may receive a signal from the detection system 5 indicating activation thereof.

[51] In one example, the control unit 30 is also configured to communicate with a building management 6, for example to receive control signals therefrom and/or to provide notifications thereto in relation to the status of the roller shutter door assembly 1.

[52] The control unit 30 may also be connected to or comprise a control panel 7, for controlling operation of the roller shutter door 10.

[53] In normal use, the control unit 30 activates the motor 14, for example in response to a user providing user input via the control panel 7. When activating the motor 14, the control unit 30 controls the braking system 16 to release the braking force applied by the braking unit 20 to the brake disc 18 by ceasing the supply of power to the braking system 16. The rotation of the axle of the motor 14 then causes the rotation ofthe barrel 12 in the desired direction, and consequently the opening or closing of the door 10.

[54] The control unit 30 then deactivates the motor 14, for example because the user ceases to provide a user input via the control panel 7. Upon deactivating the motor 14, the control unit 30 activates the braking system 16, by supplying power thereto. The braking unit 20 applies the braking force to the disc 20, preventing rotation of the barrel 12 and thus holding the door 10 in place.

[55] In the event of the control unit 30 determining that the fire/smoke detection system 5 has activated, the control unit 30 deactivates the braking system 16. Accordingly, the barrel 12 is free to rotate. In one example, the weight of the door 10 causes the door 10 to move downwardly into the closed configuration. The gearing assembly connecting the barrel 12 to the motor 14 may allow the door 10 to move downwardly at a relatively slow rate. Once closed, the door 10 acts as a fire barrier.

[56] In the event of a loss of power or a fault that renders the control unit 30 inoperable, power will no longer be supplied to the braking system 16 by the control unit 30. Accordingly, the braking system 16 will release and allow the barrel 12 to freely rotate such that the door 10 may close. [57] Due to the nature of roller shutter fire doors 10, which will typically be relatively substantial in order to resist fire, it may be undesirable for the braking system 16 to release in response to a brief interruption in mains power. Accordingly, the control unit 30 may rely on power supplied from battery 4 in order to retain the braking system 16 in its active state. The control unit 30 may then cease the supply of power to the braking system 16 when a predetermined period of time has elapsed without resumption of the power supply. The power supply may also cease to the braking system 16 when the power supplied by battery 4 is exhausted. It will be appreciated that the hold open time may depend upon the battery size, and more or larger batteries may be provided to increase the hold open time.

[58] FIG. 4A, 4B and 4C show an example roller shutter door assembly 101 . The roller shutter door assembly 101 is similar and structure and operation to the roller shutter door assembly 1 , with corresponding elements having corresponding reference numerals incremented by 100. To avoid repetition, the discussion below focuses on the different elements of the roller shutter door assembly 101 .

[59] The roller shutter door assembly 101 comprises a braking unit 120, engageable with a brake disc 118. The braking unit 120 engages the face of the brake disc 118. The braking unit 120 may be mounted on a torque arm 125, arranged to resist rotational momentum resulting from the braking unit 120 contacting the rotating brakr disc 118. Although not shown, it will be appreciated that the torque arm 125 may be fitted to a rigid part of the housing of the assembly, or another suitable mounting point.

[60] As can be seen in more detail in FIGs 4B and C, the braking unit 120 takes the form of a housing 121 having a central bore 121a, which is attachable to the torque arm 125 for example via mounting bracket 125a. The opening of the bore 121 a at the end distant from the brake disc 118 is narrower than the rest of the bore 121a, thereby forming an internally-projecting flange 121 b.

[61] A central axle 122 extends from the bracket 112a through the bore 121a. The central axle 122 has a narrower portion extending through the internally-projecting flange 121 b and wider portion disposed in the bore 121a. This defines a step 122a on the exterior of the axle 122. A biasing member 124 is located in the void defined between the flange 121 b and the step 122a, which is configured to bias the housing 121 and the axle 122 apart in an axial direction. In one example, the biasing member 124 comprises a spring.

[62] A coil 123 is disposed in the housing, which may be sealed therein by a potting compound 123a.

[63] In use, as shown in FIG. 4B, when the coil 123 is not energised, the biasing member 124 pushes the housing 121 in the direction of the mounting bracket 125a, holding it away from the brake disc 118. In this configuration, the barrel 112 may freely rotate. [64] FIG. 4C shows braking unit 120 with the coil 123 in an energised state. The coil 123 acts as an electromagnet, overcoming the force of the biasing member 124 and drawing the housing 121 into contact with the face 118a of brake disc 118. The friction between the housing 121 and the brake disc 118 prevents rotation of the barrel. In some example, the part of the housing 121 that contacts the brake disc 118 may have a high friction surface.

[65] In one example, the power required to move the braking unit 120 into contact with the brake disc 118 may be larger than the power required to maintain the braking unit 120 in position in contact with the coil 123. For example, extra power required to overcome the air gap between the housing 121 and the brake disc 118. Accordingly, in one example, the braking system 116 may supply a first level of power to the braking unit 120 to move it into contact with the brake disc 118, before reducing the level of power to a second level of power to maintain the braking force. This may find particular utility in situations where the power supplied to the braking system 116 is from the battery 4.

[66] FIG. 5A and 5B show another example roller shutter door assembly 201 . The roller shutter door assembly 201 is similar and structure and operation to the roller shutter door assembly 1 , with corresponding elements having corresponding reference numerals incremented by 200. To avoid repetition, the discussion below focuses on the different elements of the roller shutter door assembly 201 .

[67] The roller shutter door assembly 201 comprises a concentric braking system 216. The braking system 216 comprises a housing 217, an armature 218 and a hub 219, each arranged radially about the shaft 212a of the barrel 212.

[68] The coil housing 217 comprises a coil of an electromagnet, which generates a magnetic force upon receipt of power. The coil housing is secured to a mounting plate 217a, such that it radially surrounds the shaft 212a but does not interfere with the rotation thereof. For example, a bore may extend through the plate 217a and coil housing 217, which is larger than the width of the shaft 212a.

[69] The hub 219 is rotationally fixed to the shaft 212a, so that it rotates with the shaft 212a. The armature 218 comprises a ferromagnetic material and is secured to the surface of the hub 219 that faces the coil housing 217. The armature 218 is axially movable between a first position in which there is an air gap between the armature 218 and the coil housing 217, and a second position in which the armature 218 contacts the coil housing. The armature 218 may be biased to the first position, for example by a biasing member 218a such as a flat spring disposed between the hub 219 and the armature 218.

[70] Upon supply of powerto the coil of the coil housing 217, the magnetic attraction of armature 218 to the coil overcomes the bias of the biasing member 218a and the armature 218 is drawn to the second position, in contact with the coil housing 217. Friction between the armature 218 and the coil housing 217 then prevents rotation of the shaft 212a. When the supply of power ceases, the biasing member 218a moves the armature 218 back to the first position, allowing the shaft 212a to freely rotate.

[71] In the example of FIG. 5A-B, the braking system 216 is disposed on a plate 217a between the end of the barrel 212 and the mounting bracket (not shown) rotatably supporting the shaft 212a. However, in other examples, the mounting bracket (not shown) may be disposed between the braking system 216 and the barrel 212. Furthermore, whilst the example of FIG. 5A-B shows the braking system 216 arranged on the side of the mounting plate 217a most distant from the barrel 212, it could equally be arranged on the side of the mounting plate 217a proximate to the barrel 212.

[72] FIG. 6 is a flowchart of an example method. In block S61 , a braking force is applied to prevent rotation of a barrel of a roller shutter door. In block S62, the braking force is released in response to detection of a fail-safe condition. The fail-safe condition may be a loss of power, fault or receipt of a fire/smoke detect signal as discussed herein. The method may comprise further steps, as discussed herein.

[73] Various modifications may be made to the above-described examples within the scope of the disclosure. Whilst the above-described examples include a tubular motor, any of the examples above may instead comprise a motor disposed remotely from the barrel and connected thereto via a suitable drive connection, such as a drive chain or belt. The application of a reduced level of power after overcoming an air gap may be applicable to all of the examples described here. Although the examples show a braking system arranged at the end of the barrel at which drive is received, the brake disc could instead be arranged at the opposing end of the barrel, or at any position along the barrel. In other examples, the brake disc may be located on the support shaft 12a rather than the barrel itself. In further examples, braking systems may be arranged at both ends of the barrel.

[74] The size of the brake disc and braking unit may be varied. For example, a brake disc with a relatively large diameter may reduce the braking force required. In the example of FIG. 3, the braking unit may be mounted on a torque arm in a similar manner to the example of FIG. 4A-C.

[75] At least some of the example embodiments described herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as ‘component’, ‘module’ or ‘unit’ used herein may include, but are not limited to, a hardware device, such as circuitry in the form of discrete or integrated components, a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks or provides the associated functionality. In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to execute on one or more processors. These functional elements may in some embodiments include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements.

[76] Advantageously, the above-described examples provide a convenient means of preventing a roller shutter door from being held open in the event of a fire or other emergency situation. The above-described examples instead allow the brake system holding the door in place to disengage in response to power cut or alarm signal, such that the door may return to a closed position.

[77] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[78] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[79] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[80] The invention is not restricted to the details of the foregoing embodiments). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.