WO2004067095A1

WO2004067095A1 - Improved fall restraint system

Info

Publication number: WO2004067095A1
Application number: PCT/GB2004/000185
Authority: WO
Inventors: David Riches
Original assignee: Hadrian Iye (England) Limited
Priority date: 2003-01-29
Filing date: 2004-01-21
Publication date: 2004-08-12
Also published as: GB0301968D0; GB2397845A

Abstract

A fall restraint system for persons working at height on a roof comprising a first restraining means for restraining the person from moving beyond a first side edge of the roof and second restraining means for restraining the person from moving beyond first and second end edges of the roof, said first and second end edges extending from and being perpendicular to said side edge of the roof.

Description

IMPROVED FALL RESTRAINT SYSTEM

The present invention relates to an improved fall restraint system and in particular an improved fall restraint system for preventing persons from falling from the roof of a structure.

When working on a roof of a structure, during maintenance, assembly or inspection thereof, the worker is at risk from potentially fatal injury if he should fall from the roof. Accordingly it is usual to utilise a safety system for the worker comprising a safety harness, worn by the worker, to which is connected a safety line, the other end of the safety line being tethered to a moveable or fixed anchor point on the roof. Such safety system may comprise a fall arrest system (FAS) wherein the system is designed to arrest the fall of the worker should the worker fall uncontrollably, either down the roof or over the gutter or gable edges of the roof, or a fall restraint system (FRS) wherein the length of the safety line and the position of the anchor point are such that the person is restrained from reaching or moving beyond the gutter and/or gable edge of the roof to prevent the occurrence of a fall. Figures 1 to 4 disclose a known fall restraint system for preventing the working from falling over the gutter edge of the roof.

Fig 1 shows a known fall restraint system (FRS), in which a safety track 1 is secured to the roof structure at or near the ridge 2 of a sloping roof 3, equal in length to the ridge and running parallel to the ridge 2. A sliding device 4 is slidably mounted on the safety track 1 for movement along the track in both directions, and is prevented from disengaging the track at the ends by a stop 5. The sliding device 4 has an attachment point for the attachment of a safety line 6, which in turn is be attached to a worker's safety harness 7.

A worker is shown at four different places of work at positions "A" "B" "C" and "D". At positions "A" "B" and "C" the safety line 6 is at its maximum length thus preventing the worker from reaching gutter edge 8 and thus preventing a fall over this edge. At position "D" the same is true except at this position a swing- fall over gable edge 9 (the trajectory of which is described by arrowed dashed line in Fig. 1 ) cannot be prevented. Consequently in such emergency situations the hitherto FRS is called on to act as a fall arrest system (FAS). The safety line 6 may be over-stressed as it is pulled upwardly and over the gable edge 9, leading to severing, which in turn would result in a fall to the ground.

Fig 2 illustrates schematically the known FRS of Fig. 1 , wherein a worker is shown in a position where safety line 6 is at its maximum length thus preventing the worker from reaching gutter edge 8 and thus preventing a fall over this edge. However, at this position a swing-fall over gable edge 9 (the trajectory of which is described by arrowed dashed line in Fig. 2) cannot be prevented. The length of the safety line 6 may be such that distance between where the safety line 6 makes contact with the gable edge 9 and the ground is smaller than the maximum length of safety line 6 which would allow the worker to suffer a collision with the ground.

Fig 3 illustrates schematically the known FRS of Figs. 1 , 2 and 3, but with supplemental peg-type stop protection in the form of one or more peg stops 10 installed on gable edge 9. A worker is shown in a position where the safety line 6 is at its maximum length preventing the worker from reaching the gutter edge 8 and thus preventing a fall over this edge. However, at this position a swing-fall over the gable edge 9 (the trajectory of which is described by an arrowed dashed line) cannot be prevented. Consequently in such emergency situations the hitherto FRS is called on to act as a FAS. However, the position of peg stop 10 is such that the swing motion of the safety line 6 is intercepted which reduces the likelihood of a fall to the ground as in Fig. 2 or severing of the safety line as in Fig. 1.

Several peg stops 10 may have to be installed along the gable edge so that wherever a fall takes place the swinging motion of the safety line 6 is intercepted. These have to be of a height to ensure that the safety line 6 is retained and will not slip off the peg stop 10. The peg stops 10 have to be of sufficient strength to maintain the impact forces as does the surrounding structure which may make their installation impractical apart from detracting from the building aesthetics. Furthermore although peg stops 10 reduce the gable end risks they do not altogether eliminate them. The safety line 6 may still be prone to severing if the gable edge conditions and forces involved are of sufficient detriment. If not severed, rescue methods will also need to be employed to recover the worker who will be suspended by the safety line after being arrested.

Fig 4 shows the same kind of known fall restraint system as shown in Figs. 1 and 2, but with supplemental single belay point protection installed inboard from the gable edge 9. A safety line 6 is attached between sliding device 4 and worker's safety harness 7 but additionally is reeved or threaded through a belay ring 11 which itself is secured to the roof 3.

A worker is shown at a position where the safety line 6 enters the belay 11 and exits it shown by the length 6'. At this position the safety line 6 is at a length to allow access to whilst simultaneously preventing the worker from going beyond the gable edge 9. The belay ring 11 acts as an anchor for the safety line 6 and movement of worker is restricted to a locus described by radius of length 6', thus preventing a fall over the gable edge 9.

The worker is also shown at another position where the safety line 6 enters the belay ring 11 and exits it shown by the length 6". To achieve this position of access where the gutter edge 8 meets the gable edge 9 the safety line 6 has to be lengthened to length 6". At this length the belay ring 11 cannot prevent a swing-fall over the gable edge 9 as described by broken arrowed line as length 6" is greater than length 6'. Whereas severity of such a fall may be reduced as compared to the same type of hazards described in Figs. 1 and 2, the portion of safety line 6" may still be prone to severing if the gable edge conditions and forces involved are of sufficient detriment. If not severed, rescue methods will also need to be employed to recover the worker who will be suspended by the safety line 6 after being arrested.

This situation could only be overcome if a series of belay rings could be installed into the roof - each ring could be utilised to gain safe access to a limited area of gable edge 9. However this may not be possible due to roof structure and/or cost. It would also mean that the worker would have to repeatedly connect and disconnect the safety line 6 through successive belay rings necessitating a backwards and forwards motion between the line of belay rings and the gable edge, which would be impractical.

The invention seeks to overcome the disadvantages of the prior art fall restraint systems by providing a fall restraint system that permits the worker to reach substantially all regions of the roof top whilst restraining the worker from falling over the gutter edge whilst at the same time restraining the worker from movement beyond the gable edges of the roof to prevent a fall therefrom.

According to the invention there is provided a fall restraint system for persons working at height on a roof comprising a first restraining means for restraining the person from moving beyond a first side edge of the roof and second restraining means for restraining the person from moving beyond first and second end edges of the roof, said first and second end edges extending from and being perpendicular to said side edge of the roof.

Where the roof comprises a pitch roof, said first side edge comprises the gutter edge of the roof and said first and second end edges comprising the gable edges of the roof extending from the ridge to the gutter edge. In a first embodiment of the invention said first restraining means comprises elongate track means securable to the roof so as to lie at or adjacent the ridge or longitudinal centre line of the roof and extending parallel thereto, a sliding device being coupled to the track means to be freely displaceable therealong, a first safety line extending from said sliding device for attachment to a harness worn by a person, the maximum length of the first safety line being substantially equal to the minimum distance between the elongate track means and said first side edge of the roof, thus allowing the person to reach said first side edge whilst restraining the person from moving beyond and thus falling over said first side edge, said second restraining means comprising an anchor point securable to the roof at or adjacent said first side edge approximately midway between said end first and second edges of the roof, a second safety line extending from said anchor point and having a coupling means at a terminal end thereof, said coupling means being coupled to said first safety line to be freely displaceable therealong, the maximum length of the second safety line being substantially equal to the minimum distance between the anchor point and the end edges of the roof, such that the second safety line restrains the person from moving beyond the end edges of the roof.

The track means may be of rigid or flexible construction, in the form of a rail, rope, cable or the like. The first and/or second safety line is preferably of flexible construction in the form of a rope or cable or the like, but may comprise a rigid member, for example a glass fibre pole.

Preferably the coupling means of the second safety line comprises a loop or ring through which the first safety line can be passed. Preferably the diameter of said loop or ring is sufficient to allow the first safety line to slide freely through said coupling means.

Stop means may be mounted on the first safety line between the sliding device and the coupling means of the second safety line to restrict the movement of the coupling means up the first safety line. Stop means may be provided at the ends of the elongate track means to prevent the sliding device from disengaging the track means and to limit the travel of the sliding device.

Preferably the length of the first safety line extending between the sliding device and the persons harness is adjustable to allow the person to vary his position from the track means, whilst maintaining tension within the safety line. The safety line may be securable to the harness via a selectively operable locking device attached to the persons harness or to the sliding device, the safety line passing through the locking device, the locking device having locking means, operable to permit the safety line to slide through the locking device to vary the length thereof. Stop means may be provided on the safety line which abuts the locking device to define the maximum extended length of the safety line.

In a second embodiment of the present invention the first restraining means comprises first elongate track means securable to the roof so as to lie at or adjacent the ridge or longitudinal centre line of the roof, equal in length to said ridge or longitudinal centre line of the roof and extending parallel thereto, a first sliding device being coupled to the first track means to be freely displaceable therealong, a first safety line extending from said first sliding device for attachment to a safety harness worn by a person, the maximum length of the first safety line being substantially equal to the minimum distance between the first elongate track means and said first side edge, said second restraining means comprising second elongate track means securable to the roof so as to lie approximately midway between said first and second end edges of the roof and extending perpendicular to said first track means, a second sliding device being coupled to the second track means to be freely displaceable therealong, a second safety line extending from said second sliding device for attachment to the safety harness worn by said person, the maximum length of the second safety line being substantially equal to the minimum distance between the second track means and the first and second end edges of the roof.

The first and second track means may be of rigid or flexible construction, in the form of a rail, rope, cable or the like. The first and/or second safety line is preferably of flexible construction in the form of a rope or cable or the like, but may comprise a rigid member, for example a glass fibre pole.

Preferably the length of the first safety line extending between the sliding device and the persons harness is adjustable to allow the person to vary his position from the track means, whilst maintaining tension within the safety line. The safety line may be securable to the harness via a selectively operable locking device attached to the persons harness, the safety line passing through the locking device, the locking device having locking means, operable to permit the safety line to slide through the locking device to vary the length thereof. Stop means may be provided on the safety line, said stop means abutting the locking device to define the maximum extended length of the safety line. Alternatively, the first safety line may be retractably wound on a spring loaded reel provided on either the harness or the first sliding device, such that the first safety line is automatically retracted onto the reel as the person moves towards the first track means and is automatically extended towards its maximum length as the person moves away from the first track means towards the first side edge of the roof. The reel may be automatically lockable in the event of a sudden extension of the first safety line to prevent a fall of the person down the side of the roof.

Preferably the second safety line is retractably wound on a spring loaded reel provided on either the harness or the second sliding device, such that the second safety line is automatically retracted onto the reel as the person moves towards the second track means and is automatically extended towards its maximum length as the person moves away from the second track means. The reel may be automatically lockable in the event of a sudden extension of the second safety line to prevent a fall of the person through an open or fragile part of the roof.

In a third embodiment of the present invention the second restraining means comprises first elongate track means securable to the roof so as to lie at or adjacent the ridge (in the case of a pitch roof) or at or adjacent a second side of the roof, opposite said first side (in the case of a flat roof), equal in length to said ridge or second side of the roof and extending parallel thereto, second elongate track means securable to the roof so as to lie at or adjacent said first side of the roof, substantially equal in length to said first side and extending parallel to said first elongate track means, a first sliding device being coupled to the first elongate track means to be freely displaceable therealong, stop means being provided at the ends of the first track means to prevent the first sliding device from disengaging the first track means and to limit the travel of the first sliding device, a second sliding device being coupled to the second elongate track means to be freely displaceable therealong, stop means being provided at the ends of the second track means to prevent the second sliding device from disengaging the second track means and to limit the travel of the second sliding device, an third elongate track means, in the form of a rail, rope cable or the like of rigid or flexible construction, being coupled to and extending between said first and second sliding devices, the maximum length of the third track means being substantially equal to the minimum distance between the first and second track means, a safety line being coupled to and extending from said third track means and being connectable to a harness of a person, the maximum length of the safety line being substantially equal to the minimum distance between the third track means and the end edge of the roof closest thereto when the first and second sliding devices abut the respective stop means at a respective end of the first and second track means, the first restraining means comprising coupling means coupling the safety line to the third track means such that the safety line is freely displaceable therealong whereby that the person can move freely between the first and second elongate track means, said coupling means abutting the second sliding device when the person approaches said first side edge of the roof, thus restraining the person from falling over said first side edge.

The first and second track means may be of rigid or flexible construction, in the form of a rail, rope, cable or the like. The safety line is preferably of flexible construction in the form of a rope or cable or the like, but may comprise a rigid member, for example a glass fibre pole.

The coupling means may comprise a third sliding device, similar in construction to said first and second sliding devices. The coupling means may include locking means, which permit the coupling means to freely slide along the safety line in normal use but which automatically engages the third track means to lock the coupling means to said third track means in response to a sudden movement of the coupling means along said third track means, in order to arrest the fall of a person down the side of the roof.

The safety line may be retractably wound on a spring loaded reel provided on either the harness or the coupling device, such that the safety line is automatically retracted onto the reel as the person moves towards the third track means and is automatically extended towards its maximum length as the person moves away from the third track means. The reel may be automatically lockable in the event of a sudden extension of the safety line.

The present invention will be described further, by way of example, with reference to the accompanying drawings, in which:-

Figure 5 is a plan view of a fall restraint system according to a first embodiment of the present invention;

Figure 6 is a perspective view of the fall restraint system of Fig. 5;

Figure 7 is a plan view of a fall restraint system according to a second embodiment of the present invention;

Figure 8 is a schematic view of the safety harness arrangement for use with the fall restraint system of Fig. 7; Figure 9 is a plan view of a roof top fall restraint system according to a further embodiment of the present invention.

Figs. 5 and 6 show a fall restraint system according to a first embodiment of the present invention. A safety track 100 is installed at or near ridge 101 of a sloping roof 102 (or at or adjacent the centre line of a flat roof). A sliding device 110 is slidably mounted on the safety track 100 for movement along track 100 in both directions and is prevented from disengaging track by stops 111 ,112 provided at the ends of the track 100. A safety line 120 is attached at one end to the sliding device 110 and passes through a locking member 125 attached to a worker's safety harness 130. The locking member 125 has an operating handle or lever (not shown), whereby operation of the operating lever by the worker permits the safety line 120 to slide through the locking member 125, locking means of the locking member 125 preventing movement of the safety line 120 through the locking member 125 when the operating lever is released.

The locking member 125 permits the length safety line 120 between the locking member 125 and the sliding device 110 to be adjusted, thus allowing the worker to vary his position from the safety track 100, whilst maintaining tension within the safety line 120. A stop 135 (Fig. 6) is secured to the end of the safety line 120, which limits the maximum extended length of the safety line 120, and restrains the worker from reaching the gutter edge 103 of the roof 102. This system allows workers to reach any part of the roof in relative safety, and prevents a worker from falling over the gutter edge 103.

The safety line 6 is additionally is reeved or threaded through a diverter ring 140. The diverter ring 140 is connected to an end of a belay line 145, the other end of which is attached to a belay anchor 150 secured to a central region of the gutter edge 103 approximately midway between the gable edges 104, 105. The diverter ring 140 is of sufficient diameter to allow safety line 120 to pass freely therethrough. When belay line 145 is taut/the diverter ring 140 ensures safety line 120 is reeved through an angle.

The belay line 145 is of a fixed length, set approximately equal to or slightly less than the distance between the anchor 150 and the gable edges 104,105.

In normal use the worker can move over the roof surface and is prevented from falling over gutter edge 103 when the safety line 120 reaches its maximum length. When worker approaches a gable edge 104,105, the belay line 145 becomes taut. At this position the portion of the safety line 120 between the harness 130 and diverter ring 140 is at a length to allow access to all parts of the roof whilst simultaneously preventing the worker from going over or beyond the gable edge 104,105. The diverter ring 140 acts as an anchor for the safety line 120 depending on the amount of friction between the diverter ring 140 and the safety line 120.

As the worker moves towards the ridge 101 , the diverter ring 140 moves in an arc (shown by the dotted line in Fig. 5) about the anchor 150. The worker can shorten the safety line 120 by means of the locking member 125 to ensure that the portion of safety line 120 between the locking member 125 (and the harness 130) and the diverter ring 140 is at a length to allow access to whilst simultaneously preventing the worker from going over or beyond the gable edge 104,105.

Whilst an arrangement for a single worker is described above, it is envisaged that a number of separate sliding devices, associated safety lines and belay lines may be provided on a roof to enable a number of workers to carry out activities on the roof simultaneously.

Drawbacks of the first embodiment include: (i) possible reduced falls over the edge because of slippages of the diverter ring 140 over the safety line 120, and (ii) difficulties in obtaining safe access to corner areas where the gable edge 104,105 meets the ridge 101 , because of the fixed length of the belay line 145. To solve (i) a locking device similar to the locking member 125 could be utilised, mounted on safety line 120 immediately above the diverter ring 140 which would prevent the diverter ring 140 from slipping up the safety line 120. Solving both (i) and (ii) leads to the preferred embodiment of the present invention as shown schematically in Fig. 7.

Fig. 7 illustrates a plan view of the preferred embodiment of the present invention in which a safety track 200 is installed at or near the ridge 204 of a sloping roof 205 (or centre line of a flat roof), equal or near equal in length to the ridge 204 and running parallel to the ridge 204. A sliding device 210 is slidably mounted on the safety track 200 for movement along the track in both directions, and is prevented from disengaging the track at the ends by stops 215,216 provided at the ends of the track 200. The sliding device 210 has an attachment point for the attachment of a safety line 220, which in turn can be attached to a worker's safety harness 225, via a locking member 270 (see Fig. 8) similar to that described above in relation to the first embodiment of the invention shown in Figs. 5 and 6.

The adjustable length safety line 220 allows the worker to vary his position from the safety track 200, whiist maintaining tension within the safety line 220 an affords protection from falling over gutter edge 206.

A second safety track, the "belay track" 230 is installed so to run perpendicular or near-perpendicular and centrally disposed to safety track 200. Another sliding device the "belay slider" 235 is slidably mounted on the belay track 230 for movement up and down the track 230, and is prevented from disengaging the track at the ends by stops 240, 245.

A fixed length belay line 250 is connected from the belay slider 235 to the worker's safety harness 225 substantially equal in length to the distance between the respective gable edges 207,208 and belay track 230. In normal use a worker can move over the roof surface 205 and is prevented from falling over the gutter edge 206 when the safety line 220 reaches its maximum length. When the worker approaches a gable edge 207, 208, the belay line 250 becomes taut and prevents movement that would result in a fall over the gable edge 207, 208.

As the worker moves towards the ridge 204 the belay slider 235 is urged up belay track 230 by way of the tension in belay line 250, which ensures that the worker can never get into a position where a fall from the gable edge 207, 208 is possible. Alternatively, as the worker moves towards gutter edge 206, the belay slider 235 slides down belay track 230 by virtue of the weight of belay slider 235, which ensures that the worker can never get into a position where a fall from the gable edge 207, 208 is possible. Movement across the roof top 205 is therefore permissible and where access is required to any element of roof edge either the safety line 220 or the belay line 250 provides restraint. The belay track 230 ensures the worker's motion can remain parallel to gable edges 207, 208.

The belay line 250 may be a single length of rope, or alternatively may be wound and secured onto a drum, which is torsionally spring biased in one direction so as to allow extraction of the belay line 250 under a light tension and to retract the line back on the drum automatically. This assembly is itself securable to the belay slider 235. This would ensure that as the worker moved to and from the belay track 230 no slack would be allowed to form in belay line 250. The maximum extended length of belay line 250 would be equal to that of the fixed length variant.

Fig 8 shows a harness 225 for use with the fall restraint system of Fig. 7 and shows a schematic cross-section of the worker's body at the midriff, contained by a waist belt strap portion 260 of the harness 225. The safety line 220 passes through the locking member 270 which is connected to a fixing ring 265 attached to the front of the waist belt portion 260. The other end of adjustable length safety line 220 is connected to the sliding device 210 as described above in relation to Fig. 7. The unused portion of the safety line 220' exits the locking member 270. The belay line 250 is connected at to a side attachment link 275 mounted on the waist belt portion 260 of the harness 225 to be freely slideable around back of waist belt portion 260 as indicated by arrows and positions A, B and C. This enables the take off point of belay line 250 to be moved around the back of the worker's body when the worker moves from one end of the roof to the other, and in so doing passes over the belay track 230.

Fig 9 shows a further embodiment of the present invention in which two safety tracks 300, 301 are installed respectively at or adjacent the ridge 311 and gutter edge 312 of a sloping roof 310 (or at opposite sides of a flat roof) equal or near equal in length to the ridge 311 and running parallel to the ridge and to each other. At least one sliding device 320, 321 is slidably mounted on each safety track 300, 301 for movement along the respective track in both directions, each sliding device being is prevented from disengaging the track at the ends by stops 305, 306, 307, 308 provided at the ends of the each track 300, 301.

Each sliding device 320, 321 has an attachment point to which is attached an end of a fixed length safety line 330, of rigid or flexible construction, such that the fixed length safety line 330 extends between and is connected to a sliding device 320, 321 on each safety track 300, 301 such that the safety line 330 extends substantially perpendicular to the safety tracks 300, 301 , each sliding device 320, 321 to which the safety line is connected thus being constrained to slide in parallel concert with each other. A short connecting lanyard 340 is slideably mounted on the safety line 330 for movement therealong, either directly or via a sliding device (not shown), the free end of the connecting lanyard 340 being securable to a worker's safety harness 345.

In normal use a worker can move over the roof surface and is prevented from falling over gutter edge 312 when short connecting lanyard 340, or its sliding device, abuts the sliding device 320, 321 mounted on the safety track 301 adjacent the gutter edge 312 and connected to the lower end of the safety line 330. When the worker approaches a gable edge 313, 314, the sliding devices 320, 321 , connected to the safety line 330 to which the worker is attached via the lanyard 340, abut the respective stops 305,306,307,308 on the safety tracks 300, 301 and the worker is prevented from the reaching gable edge 313, 314 by the short lanyard 340. The safety line 330 may be fitted with a proprietary sliding device with an automatic locking feature, connecting the worker to said safety line 330 via the short lanyard 340. This would allow movement along the safety line 330 but the proprietary sliding device would automatically lock to said safety line if the worker should slip down the slope.

Whilst an arrangement for a single worker is described above, it is envisaged that a number of separate sliding devices, associated safety lines and lanyards may be provided on a roof to enable a number of workers to carry out activities on the roof simultaneously.

Claims

1. A fall restraint system for persons working at height on a roof comprising a first restraining means for restraining the person from moving beyond a first side edge of the roof and second restraining means for restraining the person from moving beyond first and second end edges of the roof, said first and second end edges extending from and being perpendicular to said side edge of the roof.

2. A fall restraint system as claimed in claim 1 , wherein the roof comprises a pitch roof, said first side edge comprises the gutter edge of the roof and said first and second end edges comprising the gable edges of the roof extending from the ridge to the gutter edge.

3. A fall restraint system as claimed in any preceding claim, wherein said first restraining means comprises elongate track means securable to the roof so as to lie at or adjacent the ridge or longitudinal centre line of the roof and extending parallel thereto, a sliding device being coupled to the track means to be freely displaceable therealong, a first safety line extending from said sliding device for attachment to a harness worn by a person, the maximum length of the first safety line being substantially equal to the minimum distance between the elongate track means and said first side edge of the roof, thus allowing the person to reach said first side edge whilst restraining the person from moving beyond and thus falling over said first side edge, said second restraining means comprising an anchor point securable to the roof at or adjacent said first side edge approximately midway between said end first and second edges of the roof, a second safety line extending from said anchor point and having a coupling means at a terminal end thereof, said coupling means being coupled to said first safety line to be freely displaceable therealong, the maximum length of the second safety line being substantially equal to the minimum distance between the anchor point and the end edges of the roof, such that the second safety line restrains the person from moving beyond the end edges of the roof.

4. A fall restraint system as claimed in claim 3, wherein the track means is of rigid or flexible construction, in the form of a rail, rope, cable or the like.

5. A fall restraint system as claimed in claim 3 or claim 4, wherein the first and/or second safety line is of flexible construction in the form of a rope or cable or the like, or comprises a rigid member, for example a glass fibre pole.

6. A fall restraint system of claim 3, wherein the coupling means of the second safety line comprises a loop or ring through which the first safety line can be passed.

7. A fall restraint system as claimed in claim 6, wherein the diameter of said loop or ring is sufficient to allow the first safety line to slide freely through said coupling means.

8. A fall restraint system as claimed in any one of claims 3 to 7, wherein stop means are mounted on the first safety line between the sliding device and the coupling means of the second safety line to restrict the movement of the coupling means up the first safety line.

9. A fall restraint system as claimed in any one of claims 3 to 8, wherein stop means is provided at the ends of the elongate track means to prevent the sliding device from disengaging the track means and to limit the travel of the sliding device.

10. A fall restraint system as claimed in any one of claims 3 to 9, wherein the length of the first safety line extending between the sliding device and the persons harness is adjustable to allow the person to vary his position from the track means, whilst maintaining tension within the safety line.

11. A fall restraint system as claimed in claim 10, wherein the safety line is securable to the harness via a selectively operable locking device attached to the persons harness or to the sliding device, the safety line passing through the locking device, the locking device having locking means, operable to permit the safety line to slide through the locking device to vary the length thereof.

12. A fall restraint system as claimed in claim 11 , wherein stop means are provided on the safety line which abuts the locking device to define the maximum extended length of the safety line.

13. A fall restraint system as claimed in claim 1 or claim 2, wherein the first restraining means comprises first elongate track means securable to the roof so as to lie at or adjacent the ridge or longitudinal centre line of the roof, equal in length to said ridge or longitudinal centre line of the roof and extending parallel thereto, a first sliding device being coupled to the first track means to be freely displaceable therealong, a first safety line extending from said first sliding device for attachment to a safety harness worn by a person, the maximum length of the first safety line being substantially equal to the minimum distance between the first elongate track means and said first side edge, said second restraining means comprising second elongate track means securable to the roof so as to lie approximately midway between said first and second end edges of the roof and extending perpendicular to said first track means, a second sliding device being coupled to the second track means to be freely displaceable therealong, a second safety line extending from said second sliding device for attachment to the safety harness worn by said person, the maximum length of the second safety line being substantially equal to the minimum distance between the second track means and the first and second end edges of the roof.

14. A fall restraint system as claimed in claim 13, wherein the first and second track means is of rigid or flexible construction, in the form of a rail, rope, cable or the like.

15. A fall restraint system as claimed in claim 13 or claim 14, wherein the first and/or second safety line is of flexible construction in the form of a rope or cable or the like, or comprises a rigid member, for example a glass fibre pole.

16. A fall restraint system as claimed in any one of claims 13 to 15, wherein the length of the first safety line extending between the sliding device and the persons harness is adjustable to allow the person to vary his position from the track means, whilst maintaining tension within the safety line.

17. A fall restraint system as claimed in claim 16, wherein the safety line is securable to the harness via a selectively operable locking device attached to the persons harness, the safety line passing through the locking device, the locking device having locking means, operable to permit the safety line to slide through the locking device to vary the length thereof.

18. A fall restraint system as claimed in claim 17, wherein stop means is provided on the safety line, said stop means abutting the locking device to define the maximum extended length of the safety line.

19. A fall restraint system as claimed in claim 16, wherein the first safety line is retractably wound on a spring loaded reel provided on either the harness or the first sliding device, such that the first safety line is automatically retracted onto the reel as the person moves towards the first track means and is automatically extended towards its maximum length as the person moves away from the first track means towards the first side edge of the roof.

20. A fall restraint system as claimed in claim 19, wherein the reel is automatically lockable in the event of a sudden extension of the first safety line to prevent a fall of the person down the side of the roof.

21. A fall restraint system as claimed in any one of claims 13 to 20, wherein the second safety line is retractably wound on a spring loaded reel provided on either the harness or the second sliding device, such that the second safety line is automatically retracted onto the reel as the person moves towards the second track means and is automatically extended towards its maximum length as the person moves away from the second track means.

22. A fall restraint system as claimed in claim 21 , wherein the reel is automatically lockable in the event of a sudden extension of the second safety line to prevent a fall of the person through an open or fragile part of the roof.

23. A fall reslraiπl system as claimed in claim 1 or claim 2, wherein the second restraining means comprises first elongate track means securable to the roof so as to lie at or adjacent the ridge (in the case of a pitch roof) or at or adjacent a second side of the roof, opposite said first side (in the case of a flat roof), equal in length to said ridge or second side of the roof and extending parallel thereto, second elongate track means securable to the roof so as to lie at or adjacent said first side of the roof, substantially equal in length to said first side and extending parallel to said first elongate track means, a first sliding device being coupled to the first elongate track means to be freely displaceable therealong, stop means being provided at the ends of the first track means to prevent the first sliding device from disengaging the first track means and to limit the travel of the first sliding device, a second sliding device being coupled to the second elongate track means to be freely displaceable therealong, stop means being provided at the ends of the second track means to prevent the second sliding device from disengaging the second track means and to limit the travel of the second sliding device, an third elongate track means, in the form of a rail, rope cable or the like of rigid or flexible construction, being coupled to and extending between said first and second sliding devices, the maximum length of the third track means being substantially equal to the minimum distance between the first and second track means, a safety line being coupled to and extending from said third track means and being connectable to a harness of a person, the maximum length of the safety line being substantially equal to the minimum distance between the third track means and the end edge of the roof closest thereto when the first and second sliding devices abut the respective stop means at a respective end of the first and second track means, the first restraining means comprising coupling means coupling the safety line to the third track means such that the safety line is freely displaceable therealong whereby that the person can move freely between the first and second elongate track means, said coupling means abutting the second sliding device when the person approaches said first side edge of the roof, thus restraining the person from falling over said first side edge.

24. A fall restraint system as claimed in claim 23, wherein the first and second track means are of rigid or flexible construction, in the form of a rail, rope, cable or the like.

25. A fall restraint system as claimed in claim 23 or 24, wherein the safety line is of flexible construction, in the form of a rope or cable or the like, or comprises a rigid member, for example a glass fibre pole.

26. A fall restraint system as claimed in any one of claims 23 to 25, wherein the coupling means comprises a third sliding device, similar in construction to said first and second sliding devices.

27. A fall restraint system as claimed in any of claims 23 to 25, wherein the coupling means includes locking means, which permit the coupling means to freely slide along the safety line in normal use but which automatically engages the third track means to lock the coupling means to said third track means in response to a sudden movement of the coupling means along said third track means, in order to arrest the fall of a person down the side of the roof.

28. A fall restraint system as claimed in any one of claims 23 to 27, wherein the safety line is retractably wound on a spring loaded reel provided on either the harness or the coupling device, such that the safety line is automatically retracted onto the reel as the person moves towards the third track means and is automatically extended towards its maximum length as the person moves away from the third track means.

29. A fall restraint system as claimed in claim 28, wherein the reel is automatically lockable in the event of a sudden extension of the safety line.

30. A fall restraint system substantially as herein described with reference to the accompanying drawings.