GB2471140A

GB2471140A - Fire shutter with brake released by main or auxiliary supply

Info

Publication number: GB2471140A
Application number: GB0910677A
Authority: GB
Inventors: Andrew James Mackie; John Patrick O'sullivan
Original assignee: DOOR MAINTENANCE GROUP Ltd
Current assignee: DOOR MAINTENANCE GROUP Ltd
Priority date: 2009-06-19
Filing date: 2009-06-19
Publication date: 2010-12-22
Anticipated expiration: 2029-06-19
Also published as: GB0910677D0; GB2471140B

Abstract

A method of deploying a fire shutter system is disclosed. The fire shutter comprises a motor 1 for operating the shutter. The motor 1 may be a tubular motor (fig.2) comprising motor section 102, gear section 103 and a brake mechanism 104. The method involves using a primary power source, if available, to release the brake and operate the shutter. If the primary power source is not available (e.g. due to fire), an auxiliary power source, such as a battery, is used to release the brake, thus permitting the fire shutter to close under its own weight. Keywords: roller shutter brake auxiliary power.

Description

Fire shutter motor and apparatus comprising fire shutter motor The present invention relates to fire shutter motors and in particular (but not exclusively) so-called tubular motors.

The use of retractable fire shutters to form a barrier to the passage of fire s well known. A motor is typically arranged to deploy the shutter across an opening so as to form a fire barrier. The shutter is usually formed from a plurality of linked members, the links permitting relative movement of the member so that the shutter may form a roll. The shutter is typically movable between a retracted configuration in which the shutter is up and a deployed configuration in which the shutter is deployed across the opening. The shutter may be retracted when it is desirable to use the aperture (for example, a serving hatch) . The shutter is usually deployed when it is no longer desirable to use the aperture (for example, at the end of a working day) . It is also desirable for the shutter to be deployed in the event of a fire. A fire will typically trigger a fire alarm circuit, an output from which will be fed to the fire shutter motor, causing the deployment of the fire shutter.

The motor is typically powered by mains electricity, and the apparatus and motor mentioned above work well until mains power to the motor is lost (for example, if a wire between the motor and mains electricity is melted or if mains power supply is inoperable [for example, if a circuit breaker associated with the mains power supply has "tripped"}) . In order to overcome this problem, some fire shutter deployment mechanisms comprise a failsafe mechanism so that the shutter is deployed in the event that mains power to motor is lost. There are problems, however, with some of these failsafe mechanisms, and the motor and apparatus of the present invention seek to address one or more of these problems.

In accordance with a first aspect of the present invention, there is provided a fire shutter motor for moving a fire shutter between retracted and deployed positions, the fire shutter motor comprising a stator and a rotor, the rotor being rotatable to cause movement of a fire shutter, the motor comprising a braking mechanism for inhibiting the movement of the rotor, wherein the braking mechanism is operable between a braking mode in which rotation of the rotor is inhibited and a release mode in which rotation of the rotor is permitted, the braking mechanism being operable so that the braking mechanism is in the braking mode when no voltage is applied to the braking mechanism and being operable so that the braking mechanism is in the release mode when a voltage greater than a threshold is applied to the braking mechanism.

Those skilled in the art will realise that the fire shutter is not part of the motor of the first aspect of the present invention.

The motor of the present invention typically provides a motor which has a low power consumption. Furthermore, the motor of the first aspect of the present invention may be used as part of a fire shutter deployment apparatus having an improved failsafe mode (in the absence of a primary power supply (such as in the absence of mains electricity) an auxiliary power source, such as a battery, may be used to operate the braking mechanism into the release mode, therefore permitting a fire shutter to move towards a deployed position under its own weight) The motor may be provided with a first set of electrical contacts, said first set being for operating the braking mechanism. The motor may be provided with a second set of electrical contacts, said second set being for moving a fire shutter. The motor may be arranged so that power may be supplied to the braking mechanism independently of power being supplied for movement of the fire shutter.

The motor may comprise a gear set comprising one or more gears associated with rotor, the gear set being provided for converting the rate of rotation of a rotating rotor into a desirable velocity of motion of a shutter. The gear set is typically selected and arranged so as to facilitate the provision of an appropriate force to a shutter from the motor.

Furthermore, the gear set may be selected so that the descent rate of a shutter when deploying in a failsafe mode is appropriate (i.e. not too fast and not too slow) The braking mechanism may comprise a solenoid. A solenoid may be operable to generate a magnetic field which may be used to move one or more further components, thus causing the braking mechanism to move between the braking and release modes.

The braking mechanism may be provided with a brake pad and a corresponding braking surface, wherein when the braking mechanism is in the braking mode, the brake pad and corresponding braking surface contact one another to provide a frictional braking force, the braking mechanism being provided with a bias means for urging the brake pad and corresponding surface into frictional braking engagement with one another.

The bias means may typically comprise a helical spring.

The brake pad may be associated with the rotor so that rotation of the rotor causes rotation of the brake pad.

Alternatively, the corresponding surface may be associated with the rotor. Preferably, the brake pad is associated with the rotor.

If the braking mechanism comprises a solenoid, the solenoid may be operable to move one or both of the brake pad and the corresponding surface when an activating voltage is applied to the solenoid. It is preferred that the corresponding surface is movable when solenoid is activated. The corresponding surface may be provided by a braking member comprising magnetic material. It is preferred that activation of the solenoid by the application of voltage causes the corresponding surface to move, thus changing the braking mechanism from the braking to release modes.

If the braking mechanism comprises a solenoid, it is preferred that the bias means is located in a recess or a space provided in the magnet of the solenoid.

It is preferred that at least a proportion of the rotor being located within the stator. It is preferred that a considerable length of the rotor (say, at least 30%, preferably at least 50% and more preferably at least 70%) is located within the stator. This is conveniently achieved when the motor is a so-called tubular motor.

In accordance with a second aspect of the present invention, there is provided an apparatus for deploying a fire shutter, the apparatus comprising: a fire shutter motor in accordance with the first aspect of the present invention, the fire shutter motor being operable under normal operating conditions by a primary power source, and 5 an auxiliary power source which, in a primary power source failure condition, is operable to supply power to change the brake mechanism from the braking mode to the release mode.

The apparatus of the present invention is advantageous because it provides a failsafe for deploying the fire shutter when the primary power source fails, and does so at a very low power, thus saving power and electrical energy.

Those skilled in the art will realise that the main power source and the fire shutter are not necessarily part of the apparatus of the second aspect of the present invention. By disengaging the brake mechanism, the auxiliary power source permits the fire shutter to deploy under its own weight.

The auxiliary power source is generally only operable to supply power to the brake mechanism to change the brake mechanism from the braking mode to the release mode when a fire condition exists. Such a condition would be generated on the receipt of (or possibly the absence of) a suitable signal from a sensor or alarm. The sensor or alarm may already be present in a building. Alternatively, a sensor or alarm may be provided as part of the apparatus of the present invention.

The sensor may comprise a smoke detector or a temperature sensor.

The apparatus may comprise a fire shutter. The fire shutter may comprise a plurality of hinged laths. The laths typically comprise a fire-resistant material, such as a fire-resistant metal (e.g. steel) The primary power source typically comprises a source of mains electricity, but could be a portable generator, for example.

Mains electricity provides a relatively cheap and readily-available source of power.

The auxiliary power source may comprise one or more batteries, which may be rechargeable. The batteries may be arranged to be rechargeable by the primary power source. The auxiliary power source may be capable of supplying 24V. Rechargeable batteries are reliable and relatively inexpensive.

The fire shutter typically comprises a sheet or a plurality of shutter members which are linked together so that the shutter may be formed into a roll. Such a roll may be conveniently stored in a housing above an aperture to be provided with a fire shutter.

The motor may typically be a tubular motor. Such motors are* generally small and are therefore relatively easy to accommodate. A tubular motor may typically comprise an elongate rotor (typically in the form of a rod) disposed within a substantially cylindrical stator.

In accordance with a third aspect of the present invention, there is provided a fire shutter deployment method, said method comprising: providing a fire shutter deployable between a retracted position and a deployed position in which the fire shutter forms a thermal barrier providing a primary power source for moving the fire shutter between the retracted and deployed positions, an auxiliary power source and a brake for controlling the movement of the fire shutter sensing for the presence of a fire and, in the event that a fire is sensed: determining whether the primary power source is capable of moving the fire shutter from the retracted to the deployed position, and if so, using the primary power source to release the brake and move the fire shutter from the retracted to the deployed position, and in the event that the primary power source is not capable of moving the fire shutter from the retracted to the deployed position, using the auxiliary power source to release the brake, thus permitting the fire shutter to move from the retracted to the deployed position under its own weight.

The method of the third aspect of the present invention may use the motor of the first aspect of the present invention and/or the apparatus of the second aspect of the present invention.

There is provided in accordance with a fourth aspect of the present invention, a fire shutter motor for moving a fire shutter between retracted and deployed positions, the fire shutter motor comprising a stator and a rotor, the rotor being rotatable to cause movement of a fire shutter, the motor comprising a braking mechanism for inhibiting the movement of the rotor, wherein the braking mechanism is operable between a braking mode in which rotation of the rotor is inhibited and a release mode in which rotation of the rotor is permitted, the motor being arranged so that power may be supplied to the braking mechanism independently of power being supplied for movement of the fire shutter.

The motor may be provided with a first set of electrical contacts, said first set being for operating the braking mechanism. The motor may be provided with a second set of electrical contacts, said second set being for moving a fire shutter.

It is preferred that the braking mechanism is operable so that the braking mechanism is in the braking mode when no voltage is applied across the electrical contacts and being operable so that the braking mechanism is in the release mode when a voltage greater than a threshold is applied to the electrical contacts.

The motor of the fourth aspect of the present invention may comprise those features described above with reference to the motor of the first aspect of the present invention. For example, at least a proportion of the rotor may be located within the stator. The motor may be a tubular motor, for

example.

In accordance with a fifth aspect of the present invention, there is provided an apparatus for deploying a fire shutter, the apparatus comprising: a fire shutter motor in accordance with the fourth aspect of the present invention, the fire shutter motor being operable under normal operating conditions by a primary power source, and an auxiliary power source which, in a primary power source failure condition, is operable to supply power to the brake mechanism.

The method of the fifth aspect of the present invention may comprise those features described above in relation to the method of the second aspect of the present invention.

The present invention is now described by way of example with reference to the following figures of which: Figure 1 shows an example of part of a motor in accordance with the present invention; Figure 2 shows an example of the motor shown in part in Figure 1; and Figure 3 is a wiring diagram for an example of an apparatus of the present invention using the motor of Figures 1 and 2.

An example of a motor and apparatus in accordance with the present invention will now be described. The motor is denoted generally by reference numeral 1 in Figure 2. Figure 2 shows a section through the motor 1. The motor 1 is used to control the movement of a fire shutter (not shown) . Such fire shutters are well known to those skilled in the art, and may be obtained for example from Coopers Fire Ltd., Hampshire, UK; Abacus Shutters, Essex, UK; Hag Shutters and Grilles Ltd., Bristol, UK; and Al Shutters Ltd., Bolton, UK. Such shutters typically comprise a plurality of hinged laths, the laths being fire-resistant. The motor 1 comprises three distinct sections; the rotation-generating section (denoted generally by reference numeral 102), the gear set 103 and brake mechanism 104. The rotation-generating section 102 comprises an elongate rotor 105 in the form of a cylindrical rod disposed within an elongate cylindrical stator 106. The arrangement of the rotation-generating section 102 is well- known to those skilled in the art and is used in many so-called tubular motors (for example, the Neco NF200, 500, 500 and 1000 motors, Britaija Door Products Limited, Cardiff, UK) The application of electrical signal from a mains power supply (not shown) urges the rotor 105 to rotate and the rotor does indeed rotate, so long as the braking mechanism is not in a braking mode (as is described below) . Rotation of the rotor causes transmission of rotational motion via gear set 103 to a driveshaft (not shown) of the shutter, optionally via a chain and gear arrangement (such as that available for the Neco NF500 motor, available from Britalia Door Products Limited, Cardiff, UK), therefore causing the shutter to be raised and lowered as desired.

The braking mechanism 104 of motor 1 may be seen clearly in Figures 1 and 2. The braking mechanism 104 comprises a brake disk 7a which is associated with the rotor 105. The brake disk is attached to a connection portion 7 which is provided with a bore therethrough for the accommodation of an end of the rotor (or an extension part attached to the rotor). The end of the rotor (or the extension part attached to the rotor) is provided with a screw thread which mates with a corresponding thread provided on a stop member 8. The stop member 8 secures the rotor 105 to the brake disk 7a via the connection portion 7 so that rotation of the rotor 105 causes rotation of the brake disk 7a (and therefore any braking of this rotational movement caused by frictional engagement of the brake disk with another surface will cause braking of the rotor's rotational motion) . The braking mechanism further comprises a gag bit 9 which provides a surface 15 which may, in use, engage with the brake disk to produce braking of the rotation of the rotor. The gag bit is formed from a magnetic material (in this case, iron) . The gag bit 9 is associated with a solenoid 16 which comprises an iron core 12 and a coil 14 disposed about the iron core. The braking mechanism fQrther comprises a helical spring 11 which urges the surface 15 of the gag bit 9 into frictional engagement with brake disk 7a.

In the default condition (i.e. when the solenoid is not activated by the application of a suitable voltage) the braking mechanism is in the braking mode, the spring urging surface 15 into engagement with brake disk 7a, therefore inhibiting rotation of the rotor 105.

When it is desired to move the shutter, rotation of the rotor is required and so the braking mechanism must be put into release mode. This is facilitated by activating the solenoid.

Applying an appropriate voltage to the solenoid causes the gag bit to be moved towards the solenoid against the action of the I 11 spring (in a rightwards direction in Figures 1 and 2). This causes the surface 15 to disengage from the brake disk and therefore rotation of the rotor is freely permitted. When the shutter has been moved the desired distance, the voltage to the solenoid is removed and the spring urges surface 15 into frictional engagement with the brake disk.

The fire shutter is typically deployed in two cases; firstly, the shutter may be deployed as a precautionary measure, for example, at the close of a working day. Additionally, the shutter should be deployed in the event of a fire. Mains electricity will usually be used to activate the brake mechanism from the braking mode to the release mode, therefore permitting movement of the rotor. The mains electricity is then used to drive the rotor so that the fire shutter is deployed.

In the event of the mains electricity not being operable to activate the braking mechanism from the braking mode to the release mode, a relay (not shown) triggers the auxiliary power supply (in this case, two 12V rechargeable batteries) to activate the braking mechanism from the braking mode to the release mode. This permits rotation of the rotor, and the fire shutter may then be deployed by gravity. The auxiliary power source is usually only used to deploy the shutter in the event that a fire is detected.

The wiring diagram for an example of the apparatus of the present invention is shown in Figure 3. The wiring diagram shows the presence of mains electricity input 501 and an input for the fire alarm signal 502, said input being arranged so that when alarm signal is received, the brake is actuated, moving the brake from the braking mode to the release mode.

The wiring diagram also shows the outputs 503, 504 for turning the rotor in two directions. The diagram also shows the output 505 of 24V for activation of the solenoid. This 24V supplied by mains electricity if possible (with about 200V being supplied to the rotor/stator, but if mains electricity cannot be supplied to the solenoid then the required 24V is supplied by batteries. The motor is therefore arranged so that power may be supplied to the braking mechanism independently of power being supplied for movement of the fire shutter. The wiring diagram of Figure 3 is similar to known arrangements, such as those supplied with the Neco NF200 and NF500 motors (Britalia Door Products Limited, Cardiff, UK) . However, in the present case there are separate power supply arrangements for the brake mechanism and the rotor/stator so that the brake mechanism is operable separately from the rotor/stator.

Claims

Claims 1. A fire shutter motor for moving a fire shutter between retracted and deployed positions, the fire shutter motor comprising a stator and a rotor, the rotor being rotatable to cause movement of a fire shutter, the motor comprising a braking mechanism for inhibiting the movement of the rotor, wherein the braking mechanism is operable between a braking mode in which rotation of the rotor is inhibited and a release mode in which rotation of the rotor is permitted, the braking mechanism being operable so that the braking mechanism is in the braking mode when no voltage is applied to the braking mechanism and being operable so that the braking mechanism is in the release mode when a voltage greater than a threshold is applied to the braking mechanism.
2. A motor according to claim 1 wherein the motor is arranged so that power may be supplied to the braking mechanism independently of power being supplied for movement of the fire shutter.
3. A motor according to claim 1 or claim 2 wherein the motor is provided with a first set of electrical contacts, said first set being for operating the braking mechanism and a second set of electrical contacts, said second set being for moving a fire shutter.
4. A motor according to any one preceding claim comprising a gear set comprising one or more gears associated with rotor, the gear set being provided for converting the rate of rotation of a rotating rotor into a desirable velocity of motion of a shutter.
5. A motor according to any one preceding claim wherein the braking mechanism comprise a solenoid operable to generate a magnetic field for moving one or more further components, thus causing the braking mechanism to move between the braking and release modes.
6. A motor according to any one preceding claim wherein the braking mechanism is provided with a brake pad and a corresponding braking surface, wherein when the braking mechanism is in the braking mode, the brake pad and corresponding braking surface contact one another to provide a frictional braking force, the braking mechanism being provided with a bias means for urging the brake pad and corresponding surface into frictional braking engagement with one another.
7. A motor according to claim 6 wherein the brake pad is associated with the rotor so that rotation of the rotor causes rotation of the brake pad.
8. A motor according to claim 6 or claim 7, wherein the solenoid is operable to move one or both of the brake pad and the corresponding surface when an activating voltage is applied to the solenoid.
9. A motor according to claim B wherein the corresponding surface is movable when the solenoid is activated by the application of a voltage causes the corresponding surface to move, thus changing the braking mechanism from the braking mode to the release mode.
10. A motor according to any one preceding claim wherein at least a proportion of the rotor is located within the stator.
11. An apparatus for deploying a fire shutter, the apparatus comprising: a fire shutter motor in accordance with any one of claims 1 to 10, the fire shutter motor being operable under normal operating conditions by a primary power source, and an auxiliary power source which, in a primary power source failure condition, is operable to supply power to change the brake mechanism from the braking mode to the release mode.
12. An apparatus according to claim 11, wherein the auxiliary power source is operable to supply power to the brake mechanism to change the brake mechanism from the braking mode to the release mode only when a fire condition exists.
13. An apparatus according to claim 12 comprising a sensor or alarm operable to indicate the presence or absence of a fire condition.
14. An apparatus according to any one of claims 11 to 13 comprising a fire shutter.
15. An apparatus according to any one of claims 11 to 14, the auxiliary power source comprising one or more batteries.
16. An apparatus according to any one of claims 11 to 15, the motor comprising an elongate rotor disposed within a substantially cylindrical stator.
17. A fire shutter deployment method, said method comprising: * 16 providing a fire shutter deployable between a retracted position and a deployed position in which the fire shutter forms a thermal barrier providing a primary power source for moving the fire shutter between the retracted and deployed positions, an auxiliary power source and a brake for controlling the movement of the fire shutter sensing for the presence of a fire and, in the event that a fire is sensed: determining whether the primary power source is capable of moving the fire shutter from the retracted to the deployed position, and if so, using the primary power source to release the brake and move the fire shutter from the retracted to the deployed position, and in the event that the primary power source is not capable of moving the fire shutter from the retracted to the deployed position, using the auxiliary power source to release the brake, thus permitting the fire shutter to move from the retracted to the deployed position under its own weight.
18. A fire shutter motor for moving a fire shutter between retracted and deployed positions, the fire shutter motor comprising a stator and a rotor, the rotor being rotatable to cause movement of a fire shutter, the motor comprising a braking mechanism for inhibiting the * movement of the rotor, wherein the braking mechanism is operable between a braking mode in which rotation of the rotor is inhibited and a release mode in which rotation of the rotor is permitted, the motor being arranged so that power may be supplied to the braking mechanism * 17 independently of power being supplied for movement of the fire shutter.
19. An apparatus for deploying a fire shutter, the apparatus comprising: a fire shutter motor according to claim 18, the fire shutter motor being operable under normal operating conditions by a primary power source, and an auxiliary power source which, in a primary power source failure condition, is operable to supply power to the brake mechanism.
20. A fire shutter motor substantially as described herein with reference to Figures 1 and 2.

*
21. An apparatus for the deployment of a fire shutter substantially as described herein with reference to Figures 1, 2 and 3.
22. A method of deploying a fire shutter substantially as described herein with reference to Figures 1, 2 and 3.