AU693619B2

AU693619B2 - Safety system for elevated structures

Info

Publication number: AU693619B2
Application number: AU42021/96A
Authority: AU
Inventors: Ian Robb Mclachlan; Ross Charles Mclachlan
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-01-16
Filing date: 1996-01-16
Publication date: 1998-07-02
Anticipated expiration: 2016-01-16
Also published as: AU4202196A

Description

P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Actual Inventor(s): Address for service is: ROSS CHARLES McLACHLAN ROSS CHARLES McLACHLAN and IAN ROBB McLACHLAN WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 o a o a o o a e o 6 o UOOe oo o n a o W o o Attorney code: WR Invention Title: 'Safety System for Elevated Structures" Details of Associated Provisional Application No(s): PN0570 The following statement is a full description of this invention, including the best method of performing it known to me:- *s- L

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-2- The present invention relates to a safety system for arresting the fall of an object such as a person on an elevated structure.

The invention has been devised particularly, although not solely, as a safety system for protecting workers on roofs of buildings under construction from falls from the roofs.

When a roof is under construction, it is necessary for a construction worker to be able to move freely about the roof area. Existing protection systems which involve tethering a worker to a fixed anchor point on the roof structure does afford some protection against a fall but is not altogether satisfactory as it limits ~10 the extent to which the worker can move about the roof area.

The present invention seeks to provide a safety system with a movable anchor point so as to allow a person to move freely about an elevated structure; or at least a portion thereof covered by the safety system, while having provision for arresting the fall of the person on the elevated structure.

15 The invention provides a safety system for arresting the fall of an object on an elevated structure, the safety system comprising a first track adapted to be supported on the structure, a second track for connection to the first track to extend transversely thereof for movement freely therealong, and a tether, one end of the tether being adapted for connection to the second track for movement freely therealong and the other end of the tether being adapted to be fastened to the object.

With this arrangement, the object is tethered to and moveable along the second track which in turn is moveable along the first track. In this way, the object is connected to the elevated structure in a manner which allows the object to move or be moved about the structure while remaining fastened to the structure such that a fall of the object will be arrested by the safety system.

-3- The object fastened to the structure by the safety system would commonly be a person such as a construction worker. However, the safety system may be used to fasten any other object such as a piece of machinery or a building component to an elevated structure.

The elevated structure would typically be the roof area of a building under construction or repair. The elevated structure could, however, be in any other form such as a tower.

The first track may comprise a pair of spaced apart first track elements such as cables.

The cables may be supported in any suitable manner such as by spaced apart stanchions. With this arrangement, the first track is of a simple yet highly effective construction which can be conveniently erected and removed.

The second track may comprise a second track element such as a cable extending between and movable along the first track elements. The second track element may include a connecter at each end tnereof for connecting the second track element to the respective first track element for free movement therealong.

S. The connector may comprise a pulley adapted to travel along the cable which provides the respective first track element.

90006 The connector may incorporate a release mechanism for selectively detaching the end of the second track from the respective first track element.

0 The tether may comprise a tether cable. The tether cable may have a tether connector at one end thereof for sliding movement along the second track element. The tether connector may be releasably connected to the second track and in this regard the connector may comprise a shackle.

.000 The other end of the tether cabie may be coupled to a harness adapted to be worn by a person relying on the safety system.

-4- Where the safety system is used on the roof area of a building, at least one of the first track elements may comprise a portion of a peripheral cable positioned around the periphery of the roof area. The other end of the first track element may comprise a further cable positioned within and extending between opposed sides of the perimeter of the peripheral cable such that it extends generally parallel to at least one first track element.

Where the roof area has a central ridge, said other first track element would typically be positioned to extend along the ridge.

In cases where the safety system is used during installation of a covering such as roof sheeting on the frame structure of a roof, there may be a need for stanchions which can be fitted directly onto a portion of the frame structure to allow installation of the covering to commence. Once the covering reaches the stage where it needs to be installed on the portion of the frame structure directly supporting the stanchion, the stanchion can be detached from the frame structure so that the covering can be placed in position and thereafter the stanchion fixed again to the portion of the frame structure to continue to provide protection for the or each worker involved. For this purpose, the stanchion may include a base portion having a profile complementary to the profile of the Ssheeting which provides the roof covering. The base portion can be attached 20 directly onto the frame structure by suitable fixing elements such as screws. The 4, stanchion can remain in place until such time as a roofing sheet is required to be positioned on the frame structure at the location occupied by the stanchion. The base portion can then be detached to allow installation on the roofing sheet. The stanchion is then positioned on top of the roofing sheet and attached to the frame structure by way of fixing elements extending through the sheeting.

Because the base portion has a profile complementary to the profile of the roof sheeting, it can snugly locate on the sheeting. When the safety system is to be removed, the base portion of the stanchion can simply be detached from the roof structure by removing the fixing elements. The holes in the roof sheeting through M- i i i 1 i t which the fixing elements extended can then be used to receive roof fixing elements for fixing the roof sheeting in position on the roof.

Where the roof has a ridge and a track element is installed along the ridge, stanchions supporting the track element may be removably supported at spaced 5 apart intervals along the ridge. Roof sheeting can be installed on both sides of the ridge with a space therebetween extending along the ridge, which space is eventually covered by ridge capping. The stanchions are positioned along what later becomes the space between the roof sheeting on either side of the ridge and so do not impede installation of the roof sheeting. Once the safety system is no longer required, the stanchions can be removed and the ridge capping installed. Each such stanchion may be accommodated on a base which is releasably attached to the roof frame structure. The base releasably supports the stanchion and for this purpose may include a socket into which the lower end of the stanchion is received. A locking mechanism may be provided for releasably locking the stanchion in the socket. With this arrangement, the stanchions can be removed by withdrawing the stanchions from the respective bases. Thereafter, the bases can be removed from the roof structure if desired.

The bases for the stanchions may conveniently be removed from the underside of the roof covering.

20 The invention also provides a stanchion for mounting on a frame structure of a building to support a cable of a safety system as defined above, the stanchion comprising an upright portion and a base portion, the upright portion being adapted to support the cable and the base portion being adapted for releasable connection to the frame structure and having a profile complementary to a roof covering which is to be installed on the frame structure, whereby the base portion can selectively be either mounted directly on and connected to the frame structure or mounted on the roof covering and connected to the frame structure through the roof covering.

444.4* *04 440 44 4 4 4* 44 4 **44 441 4 -6- The invention will be better understood by reference to the following description of several specific embodiments thereof which is directed to a safety system for arresting the fall of a worker on the roof area of the building. The description will be made with reference to the accompanying drawings in which: Figure 1 is a schematic fragmentary perspective view of a safety system according to a first embodiment installed on a building under construction; Figure 2 is a view similar to Figure 1 with the exception that a section of the roof covering is shown installed on the roof frame structure; Figure 3 is a view similar to Figure 2 with the exception that workers are shown attached to the safety system; Figure 4 is a perspective view on an enlarged scale showing a connector and cable which provide a second track connected to a first track for movement therealong; Figure 5 is a perspective view of one type of stanchion used in the safety system; 4 6 Figure 6 is a front view of a further type of stanchion used in the safety system, the stanchion being shown attached to a beam forming part of the roof frame structure;

A

-7- Figure 7 is a side view of the arrangement shown in Figure 6; Figure 8 is a view similar to Figure 6 except that roof sheeting material is shown in position; Figure 9 is a view similar to Figure 8 with the exception that the stanchion has been removed and roof capping installed; Figure 10 is a schematic fragmentary perspective view of a safety system according to a second embodiment installed on a building under construction; Figure 11 is a perspective view of another type of stanchion used in the safety system of the second embodiment; Figure 12 is a perspective view of the underside of the stanchion shown in Figure 11; Figure 13 is a perspective view showing the stanchion of Figure 11 in position on purlins of a roof structure of the building prior to installation of roof sheeting material on the frame structure; Figure 14 is a view similar to Figure 13 with the exception that the stanchion is shown in position after installation of the roof sheeting material; and Figure 15 is an end view of the stanchion in the position shown in 20 Figure 14.

Referring to Figures 1 to 9 of the drawings, there is shown a safety system for a building 11 under construction. The building 11 has side walls 13 supporting a roof area 15. The safety system 10 is installed on the roof area to provide a safe working environment for workers on the roof area. The safety -8system is arranged to safeguard any worker who might fall while on the roof area by arresting the fall.

The roof area 15 comprises a roof frame structure 17 including beams 19 in spaced apart relationship at intervals along the length of the building and purlins 21 extending between the beams. The beams 19 each comprise two beam sections 20 angularly disposed with respect to each other to define an apex 24 which provides a ridge 22 on the roof of the building. A roof covering 23 in the form of roofing sheets 25 are supported on and fixed to the purlins 21. The roofing sheets comprise metal decking having a raised profile defined by spaced apart ribs 27. The roofing sheets are laid in overlapping relationship and are fixed to the purlins 21 by conventional roof fixing screws 29.

In the completed roof, the inner edges of the roofing sheets 25 on each side of the ridge 22 are in spaced apart relationship as is conventional practice to provide a gap 33 which is covered by capping The safety system 10 is used during construction tne roof. It comprises a peripheral cable 41 which extends around the perimeter of the roof area 15 and which is supported on stanchions 43. With this arrangement, the peripheral cable 41 provides two longitudinal cables 45 which extend along the length of the building and two transverse cables 47 at each end of the building. A further cable 49 extends along the length of the building at the ridge 22. The further cable 49 is supported at intervals along its length by stanchions 51.

*1 I Sf A transverse cable 53 is supported between the central cable 49 and each longitudinal cable The central cable 49 and each longitudinal cable 45 provides a first track along which the respective transverse cable 53 is moveable.

The transverse cable 53 provides a second track along which a tether line 59 is moveable.

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i :t :1 1 i ii" i i i i i-rUI-,..~~YUWIYSC* -9- The tether line 59 comprises a cable which is attached at one of its ends to the transverse cable 53 and which is attached at the other of its ends to a harness 61 worn by a worker 63 on the roof area With this arrangement, the point at which the tether line 59 is anchored is 5 movable about the roof area 15 to accommodate movement of the worker 63 attached to the tether line. In this regard, the tether line 59 can move back and forth along the transverse cable 53 which in turn can move back and forth along the two cables 45, 49. In the event that the worker 63 falls while on the roof area the fall is arrested by the safety system before the worker contacts the ground. The tether line 59 is of course of a length which does not permit the worker to contact the ground from any position on the roof area. Deflection under load of the v- -ious cables is accounted for in this regard.

The transverse cable 53 has a connector 60 at each end thereof for connecting that cable to the cables 45, 49 for free movement therealong. Each connector comprises a snatch-block 62 supporting a pulley 64 for rolling movement along the respective cable 45, 49. The connector 60 includes a release mechanism 66 which allows the connector to be quickly and conveniently connected to, and disconnected from, the respective cable 45, 49.

The tether line 59 is connected to the transverse cable 53 for sliding movement 20 therealong by way of a shackle 58 adapted to be connected to, and disconnected from, the transverse cable 53 when necessary.

The stanchions 43 which support the peripheral cable 41 are, where possible, mounted onto the building 11 at a location clear of the roof purlins 21 so as not to impede installation of the roofing sheets 25. A stanchion 43 suitable for this purpose is shown in Figure 5. The stanchion 43 includes an upright portion and a lateral portion 67 having a mounting plate 69 adapted to be fastened to wall 13 of the building. With this arrangement, the lateral portion 67 supports the 4 41 4 I At £444 4.44l 4 44, 4444( 44 4P .444, 4 4

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i- 1 1- L. upright portion 65 in a position clear of the peripheral edge of the roof frame structure 17 so as not to impede installation of the roofing sheets The stanchions 51 which support the central cable 49 are installed at the apex 24 of each beam 19 and are supported in an attachment base 71 having a sockc,, 73 adapted to receive the lower er, of the stanchion 51. The socket 73 has a locking opening 75 which registers with a corresponding opening in the stanchion 51 to receive a locking pin 77 tor releasably retaining the stanchion in the socket. The attachment base 71 incorporates two spaced apart tubular elements 81 which locate on the top of the respective beam 19 and which are releasably clamped to the beam by way of conventional scaffolding clamps 83.

Because the stanchions 51 are positioned at intervals along the ridge 22 of the roof area, they are accommodated in the gap 33 which develops between the roofing sheets 25 as they are installed on each side of the ridge. In this way, the stanchions 51 do not impede installation of the roofing sheets 25. On completion of the roof, each stanchion 51 can be released from its attachment base 71 by removal of the locking pin 77 and then withdrawn from the socket 73, The ridge capping 35 can be installed. The attachment base 71 can remain in position for future use or can be removed. The attachment base 71 is accessible for removal from the interior of the building.

The stanchions 43, 51 are each provided with a loop 85 to which the respective cables 41, 49 can be attached by way of shackles 87. With this arrangement, the shackles 87 can be individually detached from the respective stanchions 43, 51 when it becomes necessary for each connector 60 on the ends of the transve se cable 53 to move along the cables 41, 49 passed a particular 25 stanchion. Once the connector 60 has moved passed the stanchion, the shackle 87 can be again connected in the loop 85 to retain the cable.

There are buildings where it is not possible to mount the stanchions 43 which support the peripheral cable 41 onto the side walls of the buildings and so it is 6 44 4 4,4r 0 4 ma+ 4 44 4 44O 4444 4 4,44( 4 .444 4 4 4 4 444 .5,44 4 411 L rr I -1 P -11 necessary to mount the stanchions at other positions such as onto the frame structure 17 of the roof. The embodiment shown in Figures 10 to 15 incorporate stanchions adapted to be mounted on the purlins 21 of the frame structure 17. In this embodiment, the stanchions 43 comprise an upright portion 91 and a base portion 93 formed integrally with the upright portion. The upright portion 91 has a loop 85 at its upper end to receive the peripheral cable 41. The base portion 93 is dimensioned to extend between two adjacent purlins 25 of the roof structure 17 and is provided with attachment holes 97 for receiving fixing elements 99 such as screw fasteners for fixing the base portions to the two frame elements, as shown in Figure 13. The base 93 has a profile complementary to the profile of the roof sheeting, as best seen in Figures 14 and 15. This allows the base portion 93 to be mounted on the roof sheeting once the installation of the roof sheeting reaches a position where it is impeded by the presence of the stanchion. At such a stage, the stanchion 43 is detached from the purlins 21 by removal of the fixing elements 99 and the roof sheeting then laid in position. The stanchion 43 can then be again fixed to the purlins 21, as shown in Figures 14 and 15. In this case, the fixing elements 99 extend through the roof sheeting 25. At the completion of the roof construction, the stanchion 43 can be removed by withdrawing the fixing element 99. Holes in the roof sheeting S. 20 25 which were formerly occupied by the fixing elements 99 used to hold the 4 4 0 base portion in position can be employed to receive the fixing screws 29 which 044.

Go hold the roof sheeting in position.

This arrangement avoids any damage to the roof by attachment of the stanchion Sonto the purlins 21 of the frame structure.

While the stanchions 41 of the embodiment of Figures 10 to 15 are shown at each location where a stanchion is required, it is highly likely that in practice a different type of stanchion will be employed at each of the four corners of the roof area in order to provide sufficient strength to the safety system to support the weight of falling workers.

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Date: 16 January, 1996 k -12- From the foregoing, it is evident that the present embodiments provide a simple yet highly effective safety system for protecting workers from falls from roof areas of buildings while allowing the workers to move relatively freely about the roof areas.

It should be appreciated that the scope of the invention is not limited to the scope of the embodiments described.

Throughout this specification (including the claims if present), unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or 10 group of integers but not the exclusion of any other integer or group of integers.

4040el 0 d 1L -Mo A

Claims

1. A safety system for arresting the fall of an object on an elevated structure, the safety system comprising a first track adapted to be supported on the structure, a second track for connection to the first track to extend transversely thereof for movement freely therealong, and a tether, one end of the tether being adapted for connection to the second track for movement freely therealong and the other end of the tether being adapted to be fastened to the object.

2. A safety system according to claim 1 wherein the first track comprises a pair 10 of spaced apart first track elements. 00 0 o 6

3. A safety system according to claim 2 wherein each first track element 0 °00 comprises a cable.

4. A safety system according to claim 3 wherein each cable is supported at 0 0 spaced apart intervals by stanchions. "o0 '0 15

5. A safety system according to any one of the preceding claims wherein the second track comprises a second track element extending between and 000 40o0 movable along the first track elements.

6. A safety system according to claim 5 wherein the second track element comprises a cable.

7. A safety system according to claim 5 or 6 wherein the second track element further comprises a connector at each end thereof for connecting the second track element to the respective first track element for free movement therealong. LIUULUI~U, Wlluetuy me oase portion can De selectively either mounted directly on and be connected to the frame structure or mounted on the roof covering and be connected to the frame structure through the roof covering, -14-

8. A safety system according to claim 7 wherein the connector comprises a pulley adapted to travel along the cable which provides the respective first track element.

9. A safety system according to claim 8 wherein the connector incorporates a release mechanism for selectively detaching the end of the second track element from the respective first track element.

A safety system according to any one of the preceding claims wherein the tether comprises a tether cable.

11. A safety system according to claim 10 wherein the tether cable has a connector at one end thereof for sliding movement along the second track element.

12. A safety system according to claim 11 wherein the tether connector releasably connects the tether cable to the second track.

13. A safety system according to claim 11 or 12 wherein the other end of the tether cable is adapted to be coupled to a harness to be worn by a person relying on the safety system.

14. A safety system according to any one of the preceding claims wherein at least one of the first track elements comprises a portion of a peripheral cable i positioned around the periphery of a roof area of a building.

15. A safety system according to claim 14 wherein the other one of the first track elements comprises a further cable positioned within and extending between opposed sides of the perimeter of the peripheral cable such that it extends generally parallel to said at least one first track element.

16. A safety system according to any one of the preceding claims wherein the stanchion comprises an upright portion for supporting a respective one of the N N'L 11EI IUIIUv VIIIU OL IV I I IVI I L 1 CI IUII UWOI IIJLIVI I I L 110 III V IIlII III LIUUIII j LI IV U12L method of performing it known to me:- a a 1 cables and a base portion having a profile complementary to the profile of a roof covering for a frame structure for a roof of a building.

17. A safety system according to claim 16 wherein the base portion includes at least one hole in which a fixing element can be installed for fixing the base portion to the frame structure.

18. A safety system according to any one of claims 1 to 15 wherein the stanchion is accommodated on an attachment base which is releasably attached to a frame structure of a roof of a building.

19. A safety system according to claim 18 wherein the attachment base includes S 10 a socket into which the lower end of the stanchion is receivable. 0 a

20. A safety system according to claim 19 wherein a locking mechanism is provided for releasably locking the stanchion in the socket.

21. A stanchion for mounting on a frame structure of a building to support a t cable of a safety system according to any one of the preceding claims, the stanchion comprising an upright portion and a base portion, the upright portion being adapted to support the cable and the base portion being adapted for releasable connection to the frame structure and having a profile complementary to a roof covering which is to be installed on the frame structure, whereby the base portion can be selectively either mounted directly on and be connected to the frame structure or mounted on the roof covering and be connected to the frame structure through the roof covering.

22. A stanchion according to claim 21 wherein the base portion has at least one hole for receiving a fixing element for fixing the base portion to the frame structure. A .v Ar 1 d, rr j Vr\; ,r O^~ that a fall of the object will be arrested by the safety system that a fall of the object will be arrested by the safety system. 4 'nrT 9Y) ll ii, 1 r r i -16-

23. A safety system substantially as herein described with reference to the accompanying drawings. Dated this fourth day of May 1998. ROSS CHARLES McLACHLAN Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant C c CC' C.. C CC CCC *I I( C a a «a a C i :l 1 i I CCC CCC 1 L I (Y)0 14 v ?x S 25 The other end of the tether cabie may ba coupled to a harness adapted to be worn by a person relying on the safety system. -17- ABSTRACT A safety system (10) for arresting the fall of a person (63) on an elevated structure (11) such as a building. The safety system (10) comprises a first track adapted to be supported on the structure, a second track for connection to the first track to extend transversely thereof for movement therealong, and a tether one end of the tether being adapted for connection to the second track for movement therealong and the other end of the tether being adapted to be fastened to the person The first track is provided by a pair of spaced apart first cables (45, 49) and the second track is provided by further cable (53) extending between and slidable along the first cables (45, 49). t 1 4 t o* I «4 I t I I a