GB2454892A

GB2454892A - Fire Barrier System with heat sensitive locking device

Info

Publication number: GB2454892A
Application number: GB0722856A
Authority: GB
Inventors: Richard Guthrie
Original assignee: GUTHRIE DOUGLAS Ltd
Current assignee: GUTHRIE DOUGLAS Ltd
Priority date: 2007-11-22
Filing date: 2007-11-22
Publication date: 2009-05-27
Anticipated expiration: 2027-11-22
Also published as: GB2454892B; GB0722856D0

Abstract

Mounting means 10, for a rolling fire barrier, comprising a shaft 12 arranged to be located within a rolled barrier member (2, fig.1), a collar member 28 rotatably mounted on said shaft 12 and arranged to support the fire barrier and a selectively operable locking means 27, said locking means being selectively actuable between a disengaged position in which the collar is free to rotate on the shaft and an engaged position activated by heat in which the locking means prevents rotation between the collar and the shaft. A heat frangible retaining member may retain the locking member in the disengaged position; alternatively the locking member may comprise be thermally sensitive and deform under heat such as bi-metallic strip. In use during a fire the collar 28 will rotate and deploy the fire curtain, subsequently due to the increase temperature the locking member activates and prevents further rotation of the fire curtain which may occur should a braking device of the motor fail which might occur if components of the motor melt. The locking device ensures the fire curtain remains taut and no bagging occurs and maintains its sealing function.

Description

Fire Barrier System The present invention relates to fire barriers and in particular to rolling fire barriers such as, for example, rolling fire curtains or fire shutters.

S

A typical fire barrier arrangement is shown in figure 1 and comprises a fireproof, flexible web of material 2, such as a fabric, which is attached at its top edge to a roller tube 4 and at its lower edge to a rail or bar 6. The edges of the material or curtain and the ends of the bottom rail run in guides 8 shown in phantom at each side.

The roller tube 4 is typically mounted in a housing referred to as a head box, in which is also contained a motor (not shown) for actuation of the roller tube about its longitudinal axis. The motor may be attached to one end of the roller tube and a support bearing may be attached at the opposite end such that the roller tube is supported at each end thereof within the head box.

The curtain is normally held in the retracted position within the head box. When a fire is detected by heat and/or smoke sensors, the alarm system is activated and the motor rotates the roller tube about its axis so as to pay out a length of the firecurtain. The curtain is paid out until a fully deployed condition is reached at a position determined by built-in adjustable travel limit switches within the motor.

Thus the motor ceases actuation of the roller tube after a predetermined number of revolutions or parts turns.

The curtain of figure 1 is shown in a partially deployed condition, It will be appreciated that both the weight and the rigidity of the rail 6 is important for maintaining the curtain in a substantially planar condition as it is deployed. It is also an important quality of the curtain that it maintains a close contact with the guides 8 once deployed so as to form a seal therewith and inhibit free movement of air past the curtain. --.

The curtain is retained in the deployed position by a brake built into the motor or by the self-sustaining capability of the drive train. It is important to retain the curtain at the correct length when deployed to prevent the fabric from "bagging" in the guides and thereby losing the effectiveness of the seal between the fabric and the guides.

However conventional locking or braking systems often fail to operate correctly during a fire due to an increase in temperature, since the motor, being of aluminium, copper and/or plastic parts, often melts. In order to retain the effectiveness of the seal of the curtain in its guides, it is common current practice to adjust the length of fabric fitted to the roller so that when fully deployed it cannot unroll any further. However this requires the length of curtain on each roller tube to be tailored on site by fitting the bottom rail when the curtain is fully deployed.

This complicates the installation process, which represents an unwanted cost to the supplier or fitter and means that the curtain system cannot be provided in a condition which is ready for use. The correct operation of the fire curtain is also dependent on a manual installation procedure, which is therefore subject to human error. Furthermore, once installed, the system cannot readily be adapted or transferred since it has been tailored to suit the dimensions of a specific location.

A similar problem is also associated with fire resistant rolling shutter systems which are deployed substantially in the manner described above in that failure of the motor to lock the roller barrel in situ can lead to integrity failure of the system It is an object of the present invention to provide for an improved rolling fire barrier which is simple to install and which operates correctly in varying locations.

According to a first aspect of the present invention there is provided mounting means for a rolling fire barrier, the fire barrier comprising a barrier member rolled onto a tubular member, wherein the mounting means comprises a shaft arranged to be located within the rolled barrier member, and a collar member rotatably mounted on said shaft and arranged to support said tubular member on said shaft during use, wherein the mounting means further comprises selectively operable locking means, said locking means being selectively actuable between the shaft and collar by application of heat thereto.

In one embodiment, the locking means is movable between a retracted and an engaged position, the locking means being retracted during normal operation of the fire curtain. The locking means may be selectively actuable between a retracted condition and an engaged condition. In the retracted condition, relative rotation between the shaft and collar may be enabled, whereas in the engaged condition, relative rotation between the shaft and collar may be inhibited.

The present invention is allows the roller to be locked in fire conditions, when high temperatures can lead to a risk of failure of the motor, such that the curtain cannot unwind beyond an optimum deployed length. The present invention is advantageously incorporated within the free end bearing or shaft arrangement for a rolling fire barrier such that it does not inhibit normal operation or deployment of the barrier.

The locking of a power operated rolling fire barrier system in fire conditions improves the performance of the system and better prevents the spread of flames and smoke through a building by ensuring that a planar profile of the barrier is maintained.

In one embodiment, the locking means comprises a movable member such as a pawl or key. The movable member may be biased towards a locked condition, for example, by any or any combination of a spring, gravity or magnetic biasing means. The movable member may be retained in a retracted condition by retaining means. The retaining means may comprise temperature-sensitive means.

In one embodiment the retaining means comprises a frangible sleeve. The sleeve may be formed of a plurality of sleeve portions which are connected together by heat sensitive attachment means so as to form the complete sleeve.

The heat-sensitive attachment means may comprise a solder.

According to a preferred embodiment, the retaining means is disposed about the shaft. In one particular embodiment, the retaining means passes through the locking means.

According to a second aspect of the present invention there is provided a rolling fire barrier system comprising mounting means according to the first aspect.

One or more working embodiments of the present invention are described in further detail below with reference to the accompanying drawings, of which: Figure 1 shows a three-dimensional view of a rolling fire curtain system according

to the prior art;

Figure 2 shows a three-dimensional view of mounting means for a fire curtain according to the present invention; Figure 3 shows a part cut away side view of a mounting means according to the present invention; Figure 4 shows a three-dimensionaj view of a collar member according to a preferred embodiment of the present invention; and, Figure 5 shows an end view of the collar of figure 4.

russn*,,n C In figure 2, there is shown mounting means 10 for mounting a roller tube 4 as generally shown in figure 1. The mounting means 10 forms a bearing arrangement which is insertable into an open and of the roller tube 4.

In addition to the features of figure 1, the present invention may include a number of studs or buttons (not shown) towards the peripheral edges of the curtain. Such formations are attached to the curtain such that they are located outwardly of the guides 8. The guides 8 define a narrow passage within which the curtain is held.

The studs or buttons are too large to pass through the guides and thus maintain the curtain correctly between the guides 8 during use. The studs or buttons are pitched so that they do not coincide when the curtain is rolled up.

Turning now to figure 2, the mounting means 10 comprises a shaft 12 which is fixed at one end to a bracket 14 via a bolt 15. The bracket depends from a mounting plate 16 which can be mounted on a wall or other upright member capable of supporting the rolling curtain system. The bracket and/or mounting plate are typically mounted on the inside face of a housing (not shown), commonly referred to as a head box. When the shaft 12 is attached as shown, it extends substantially perpendicularly to the mounting plate 16, such that the shaft will be generally horizontal in use.

A pair of locating members 18 and 20 are fitted to shaft 12. The locating member 18 is fitted towards the bracket end of the shaft 12, whilst the member 20 is fitted towards the free end of the shaft 20.

Each of the members 18 and 20 are generally disk shaped with a central aperture shaped to closely fit about the shaft 20. Each member 18, 20 is provided with one or more tongue-shaped formations 22 on its peripheral edge. The tongue members 22 are spaced radially about the periphery of the disk and extend in a direction perpendicular to the plane of the disk. The tongue members have a curved front end and are shaped to locate with the inside surface of the roller tube 4 during use.

The locating members 18, 20 are fitted with bearings 24 about their central aperture for location on the shaft as shown in figure 3. The disks and beatings 24 are retained in position on the shaft 20 by washers 26.

As can be seen in figure 3, within the body of the shaft 12 there is formed a first recess or bore 21 which extends laterally through the shaft 12. In addition there is a second recess 23 which forms a depression or cut-out in the outer surface of the shaft 12. The recess 23 extends longitudinally along a portion of the shaft 12 and is shaped to receive locking means in the form of a locking key or pawl 27.

The lateral recess 21 opens into recess 23 and is shaped to receive a spring 25 or a plurality of springs which act upon the locking means 27.

In figure 3, the locking pawl 27 is shown in a displaced condition. However in normal operation, the pawl is held within the recess 23 by an annular retaining means 29 such that it is flush with the surface of the shaft 12. The annular retaining means 29 is in the form of a fusible band made from two halves 29A and 298 which are soldered together with a solder having a precise melting point.

The annular band 29 passes around the outside of the shaft 12 and over or else through the body of the pawl 27. The opposing halves 29A and 29B of the band 29 are connected at a location angularly spaced from the pawl 27.

The shaft 12 is also provided with a block or stop member 31 which serves to close the bore 21 such that the spring 25 is held trapped therein against the pawl 27. Accordingly, the stop may be provided with a screw thread which corresponds with a screw thread ion the inside of the bore 21.

A collar member 28 is located on the shaft 12 part way between the free end and the bracket 14, that is between the locating members 18 and 20. The collar member is shown in further detail in figures 4 and 5 and comprises a pair of circumferential end walls 30 and 32. The end walls are similar in shape to the locating members 18 and 20 and are generally disk-shaped with tongue formations 34 spaced radially about the outer peripheral edge thereof.

The opposing end walls 30 and 32 of the collar 28 are connected by a circumferential wall 36 which retains the end walls in an axially spaced relationship. The circumferential wall 36 is generally tubular in shape in the form of a cuff or collar and is connected about its opposing peripheral edges to end walls 30 and 32. The end walls are typically connected to the circumferential wall by welding. The circumferential wall 36 has openings 38 within its surface to aid airflow through the device and transmission of heat to the retaining means 29 during use.

Each of the end walls 30 and 32 have a central aperture 40 for location about the shaft 12. However the diameter of the openings 40 is slightly greater than the diameter of the shaft 20. The openings 40 are provided with locking formations in the form of teeth or castellations 42 which are spaced about the inner periphery of the opening 40.

In this embodiment, five castellations 42 are shown on the inner periphery of the end wall 30 and a five castellations 42 are provided on the inner periphery of end waIl 32. The centre of the castellations are therefore radially spaced by 72°.

However, as shown in figure 4, the castellations on the end wall 30 are offset from the castellations 42 in end wall 32 by half the distance between the castellations in an anti-phase arrangement or sequence. Therefore each castellation on end wall 30 is radially offset from an adjacent castellation on end waIl 32 by approximately 36°. When the width of the castellations is taken into account, the gap between the castellations on the end walls is approximately 18°, when viewed end on as shown in figure 5.

Each of disks 18 and 20, and end walls 30 and 32 have a cut-out 44 in the -.

peripheral edge thereof. This cut-out 44 may be used for location of a correspondingly shaped axially extending formation (not shown) on the inside of the tube 4 during use to ensure correct alignment of the mounting members. The tube formation or groove is used for location of the fabric which is formed with a pocket or sleeve in its upper edge such that a steel rod can be inserted therein.

The rod can be located in the groove in tube 4 for ease and accuracy of fitting.

When the mounting means 10 is installed for use, the locating members 18 and and the collar 28 are located on the shaft in the order shown in figure 2. The roller curtain tube 4 is then located on the shaft by pushing the tube over the locating member 18, 20 and collar 28. The outer locating disc 18 is fixed to the roller tube 4 and the inner disc 20 is left free so that it supports the tube but can slide inside it. This enables the roller tube to rotate freely and also provides an axial adjustment for ease of installation.

The tongue formations 22 and 34 press against the inside wall of the tube 4 such that the roller tube 4 is held on the disks 18, 20 and collar by friction. Additional formations may be provided on the interior of the tube 4 to ensure a tight or else locked fitment is achieved. The tongues on disc 18 may be screwed or otherwise fixed to the roller tube 4.

In normal operation, the disks 18, 20 and collar are free to rotate about the shaft 12, which in turn allows the roller tube 4 to rotate in order to pay out a length of curtain under operation of a motor (not shown). In this state, the key or pawl is held clear of the internal surface 40 and the castellations 42 of the collar 28.

In the presence of a fire in close proximity to the rolling curtain system, the temperature of the air and the component parts of the mounting means 10 will increase. Once a predetermined temperature is achieved, the solder joining the component parts of frangible band 29 will melt such that the band is split and the pawl 27 is no longer held against the shaft 12. Under the action of the spring 25, the pawl moves radially outward of the recess 23 into engagement with the inner edge 40 of the collar 28. This condftion is shown in figure 3 in which the pawl has been at least partially ejected from the recess 23.

It will be appreciated that, because the band 29 is held within the body of the pawl 27, it does not interfere with the operation of the pawl into engagement with the internal wall of the collar 28.

The pawl becomes engaged between castellations 42 and thus locks the collar 28 relative to the shaft 12. This prevents further rotation of the collar and thus prevents further pay out of the fire curtain from the roller tube 4. Accordingly, regardless of the state of the motor, the pay out of excess curtain length will be avoided and the curtain will be held at the correct length, ensuring a good seal is maintained with guides 8.

The pawl 27 is of length greater than that of the collar such that the pawl may engage against either the castellations on the end waIl 30 or else on the end wall 32.

The spacing of the castellations 42 ensures that only a small angular movement of the collar may be needed for the pawl to correctly engage between the castellations 42. This fraction of a rotation does not significantly affect the effectiveness of the curtain. Thus, in the event that the pawl does not immediately locate in between castellations 42, the weight of the curtain will rotate the collar until locking is achieved. Accordingly, the available drop distance for the curtain is minimised. Furthermore, it is possible to shape the castellation and locking pawl, for example by providing correspondingly ramped edges, in order to ensure that the pawl is correctly urged into engagement between the castellations 42.

The temperature of the solder holding the two halves of the fusible band together is chosen so that the device will not activate except in temperatures indicative of fire conditions. In addition the solder can be selected or tailored to have a melting point below that of the component parts of the motor such that the locking pawl will be actuated in advance of the motor melting. In this way the retaining band splits before the curtain can rotate due to toss of motor braking function or the like.

Thus the melting point of the solder should be greater than the maximum ambient temperature during normal operation but less than the melting point of the relevant components of the motor. A typical activation temperature for the locking pawl will be in the region of 70 to 150°C and more preferably 85-120°C.

A further advantage is that the curtain can be supplied as a fully finished system with the fabric and bottom rail fitted and a slight excess of fabric on the roll. The device enables the finished height to be trimmed automatically using the motor limit switches without risk of the curtain bagging in the guides when the motor melts. The length of the guides 8 may be adjusted on site during installation and the finished deployed condition is self-adjusting once installed. One advantage of the present invention is that no cutting of the curtain is required on site.

Whilst the above embodiment shows multiple locating members 18 and 20 and a tubular collar member, it will be appreciated that one or more locating members may be omitted such that the roller tube 4 is located on the collar only.

Furthermore, the collar may be substantially planar or disk shaped in place of the elongate collar shape shown in the accompanying figures.

The locking pawl is shown as being mounted within the shaft, which represents a preferred embodiment. However it would also be possible to mount the locking pawl within the collar such that it is selectively engageable with castellations on the shaft. Whilst the locking pawl is preferably biased by a spring, it is possible that the locking pawl could fail into the engaged position under the action of gravity alone or else could be biased by other mechanical means such as a weight or lever, or else by a repelling force between opposing magnetic members.

In another embodiment, alternative temperature sensitive means may be provided for controlling locking of the collar relative to the shaft. The locking pawl itself may be formed of a temperature sensitive material such as a bi-metallic strip such that the locking pawl itself will deform upon the application of heat thereto between a retracted and a locking condition. Such a component may comprise two or more material strips of differing thermal expansion coefficients such that the composite strip deforms or bends upon application of heat.

In such an embodiment, one end of the pawl would typically be fixed within a recess in either of the shaft 12 or collar 28. Thus a free end of the pawl could engage the other of the shaft 12 or collar 28 during a fire condition so as to lock the collar relative to the shaft. This embodiment may replace the spring and retaining band arrangement of figure 3.

Whilst the foregoing description relates specifically to a fire curtain, it will be appreciated by those skilled in the art that the present invention could be applied to a rolling shutter arrangement, in which the curtain is replaced by a number of interlocking metal slats mounted on a roller. The series of connected slats form a barrier which can be rolled up about shaft 12 and deployed by rotation of the rolled shutter in a pay-out direction. Thus the locking of the rolling shutter system can be effected using temperature sensitive means as described above.

Claims

Claims: 1. Mounting means for a rolling fire barrier, comprising: a shaft arranged to be located within a rolled fire barrier: a collar member rotatably mounted on the shaft and arranged to support the rolled fire barrier about the shaft during use; and, locking means arranged to be selectively operable between a disengaged condition in which the locking means is removed from the force path between the collar and shaft, and an engaged condition in which the locking means is interposed in said force path so as to inhibit relative rotation between the collar and shaft, wherein the locking means is heat sensitive so as to be operable between said disengaged and engaged conditions by the application of heat thereto.
2. Mounting means according to claim 1, wherein the heat-sensitive locking means comprises a locking member and a heat-frangible retaining member for retaining the locking member in the disengaged condition.
3. Mounting means according to claim 2, wherein the retaining member is formed of a plurality of parts connect together by a heat-sensitive material.
4. Mounting means according to claim 3, wherein the heat-sensitive material is solid at ambient conditions and has a melting point in the region 70 to 150°C.
5. Mounting means according to claim 3 or 4, wherein the heat-sensitive material comprises a solder.
6. Mounting means according to any one of claims 2 to 5, wherein the retaining member is annular in shape.
7. Mounting means according to claim 6, wherein the retaining member comprises two opposing semi-annular portions.
8. Mounting means according to any one of claims 2 to 7, wherein the retaining member passes over or through the locking means.
9. Mounting means according to any preceding claim, wherein the locking member is biased towards the engaged condition by a spring.
10. Mounting means according to claim 1, wherein the locking means comprises a heat sensitive locking member.
11. Mounting means according to claim 10, wherein the locking member is deformable under the application of heat thereto between the disengaged and engaged conditions.
12. Mounting means according to claim 10 or 11, wherein the locking means comprises a bi-metallic strip.
13. Mounting means according to any preceding claim, wherein the locking means is located within a recess in one of the shaft or collar in the disengaged condition and is selectively actuable therefrom into engagement with the other of the shaft or collar.
14. Mounting means according to claim 13, wherein the shaft comprises first and second recesses, the first recess being arranged to receive the locking means in the disengaged condition and the second recess being arranged to receive means for biasing the locking means into the engaged position, wherein the second recess opens into the first recess.
15. Mounting means according to any preceding claim, wherein the collar member has an inner peripheral edge shaped to surround the shaft and wherein the inner peripheral edge has locking formations depending therefrom for cooperation with the locking means in the engaged condition.
16. Mounting means according to claim 15, wherein the locking formations comprise spaced castetlations.
17. Mounting means according to claim 15 or 16, wherein a first set of locking formations are provided at a first location on the collar and a second set of locking formations are axially spaced from the first set, the first set of locking formations being angularly offset from the second set.
18. Mounting means according to claim 17, wherein the locking means comprises a locking pawl of length greater than the axial spacing between the first and second set of locking formations.
19. A rolling fire barrier system comprising mounting means according to any one of claims I to 18.
20. Mounting means for a rolling fire barrier substantially as herein before described with reference to the accompanying drawings.