GB2392948A

GB2392948A - Double safety net

Info

Publication number: GB2392948A
Application number: GB0221367A
Authority: GB
Inventors: James Maurice Hill
Original assignee: Oxford Invest & Consulting Gro
Current assignee: Oxford Invest & Consulting Gro
Priority date: 2002-09-14
Filing date: 2002-09-14
Publication date: 2004-03-17
Also published as: GB0221367D0

Abstract

A safety net system is provided for use beneath skylight windows 18 in a flat roof 10 supported by purlins 14 where tie rails 22 are held on to the purlins 14 by tie rail clamps 24 and where a fine mesh net 28 and a heavy mesh net 32 are supported beneath the tie rails 22, the fine mesh net 28 preventing tools falling through the skylight 18 on to a warehouse or other facility floor, and the heavy mesh net 32 preventing one or more individuals from falling from the skylight 18 into the building below. The nets 28, 32 can be fed around obstructions 20 by means of slitting the nets 28, 32 to fit around the obstruction 20 and then re-binding the net with cord 50. The tie rail clamp 24 comprises a tie rail holder 40 and a C-clamp 36 for attaching to the purlin 40.

Description

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SAEETY NET

The present invention relates to safety nets for protecting individuals from falling hazards when work is being done on the 5 roof, or on skylights and the like in the roof of industrial buildings such as factories, garages and warehouses.

One falling hazard encountered when work is being done on the ceiling or roof of an industrial building is that of the individual, 10 doing the work, falling through a roof or skylight onto the floor (or intervening equipment) of the building and receiving injuries which can cripple or kill.

Another falling hazard encountered when work is being done on the 15 ceiling or roof of an industrial building is that of the individual, in the industrial building, being struck by falling individuals who are doing the work and have fallen through a roof or skylight or of being struck by falling tools or parts, dropped by the individual doing the work on the roof or skylight.

This hazard has been recognized, and, for example, in the United Kingdom, the Health and Safety Executive (an organ of the British Government) and the British Standards Institute have drawn up regulations and standards which require the provision of safety nets 25 of a certain standard or standards to be provided (indoors) beneath fragile portions of rooves to prevent falling hazards. The problem with the proposed solution is that the nets are fixed between wide apart elements of a roof, if not from the edges of the roof. The present invention seeks to provide safety net system with an 30 alternative, robust means of attachment.

Another disadvantage of the prior art safety nets is that they are

likely to stretch when an individual falls thereon, due to the potentially large separation between attachment points, and perhaps 35 even allow the falling individual to reach the ground. The present invention seeks to provide a safety net and safety net system where the chances of a safety net, when operating, of allowing a falling

individual to reach even into proximity with any item below a roof are negligible.

The prior art safety nets and their attendant standards are

5 principally aimed at catching individuals falling down within a roof. As such, they are not very effective in preventing the fall of tools and other small items from a roof or through a skylight into the interior of industrial buildings and possibly causing damage or injury to individuals inside. The present invention seeks to provide 10 a solution which not only catches individuals, but which can also catch any small item than might be dropped or spontaneously fall from a roof.

Rooves often present obstructions, such as pillars and dependent 15 lights, around which a safety net has to be employed. The prior art

safety nets simply abutted individual nets on either side of an obstruction, filling the entire area, but leaving an unsecured gap through which tools or individuals could fall. The present invention seeks to provide a safety net and safety net system where 20 obstructions do not present a further hazard through which individuals or items can fall.

The present invention can be used beneath glass Hooves, beneath flat or sloping rooves, beneath internal ceilings of buildings, and 25 anywhere where there is a risk of a falling hazard. The buildings are not restricted to industrial buildings, but, non exclusively, can also encompass schools, shopping malls, retail warehouses, hospitals, office buildings, government buildings and normal flats, houses and other types of dwellings.

According to a first aspect, the present invention consists in a safety net system for a roof, where a roof skin is supported on purling, said system comprising: a first tie rail; first tie rail attachment means to attach said first tie rail to two or more a 35 purling; a second tie rail, spaced from said first tie rail; second tie rail attachment means to attach said second tie rail to said two

or more a purling; and a mesh, for suspension between said first tie rail and said second tie rail.

According to a second aspect, the present invention consists in a 5 method for providing a safety net system for a roof, where a roof skin is supported on purling, said method comprising the steps of: providing a first tie rail; attaching said first tie rail first tie rail to two or more a purling; providing a second tie rail, spaced from said first tie rail; attaching said second tie rail to said two 10 or more a purling; employing a mesh for preventing falling; and suspending said mesh between said first tie rail and said second tie rail. The invention further provides that the mesh can comprise a first 15 light mesh for attachment to the first and second tie rails using light attachment means, and that the light attachment means can comprise at least one of cable tie wraps, light cord, light clamps light clips, light hooks and catches. The invention further provides that light mesh can be capable of stopping tools or other items 20 falling.

The invention further provides that the mesh can comprise a second heavy mesh for attachment to the first and second tie rails using heavy attachment means, and that the heavy attachment means can 25 comprise at least one of heavy cord, heavy clamps, heavy clips, heavy hooks and substantial catches. The invention further provides that heavy mesh can be capable of stopping one or more individuals falling. 30 The invention further provides that the light mesh can have a lighter form and finer pitch than the heavy mesh.

The invention further provides that an obstruction can be overcome by slitting the light mesh and/or the heavy mesh to allow the slit 35 mesh to pass around the obstruction, the spilt in the mesh being made good by re-attaching the edges of the slit together. The

invention further provides that the re-attaching of the slit edges can be achieved by cord, by welding, by clamps and by clips.

The invention further provides that the tie rails can be attached to 5 the purlins by tie rail clamps, that each tie rail clamp can comprise clamp means for attaching the tie rail clamp to the purlin, and that each tie rail clamp can comprise a tie rail holder, attached to the tie clamp to support the tie rail beneath the purlin. The invention also provides that a tie rail can be supported beneath a purlin by means of welding, by means of binding or tying with cord, by gluing, by using and screw fixings, and by any other means capable of attaching a tie rail to a purlin.

The invention further provides that the first mesh can be polymer, natural fibre, metal (including steel), ceramic or mineral material, or any combination thereof.

20 The invention further provides that the heavy mesh can be polymer, natural fibre, metal (including steel), ceramic or mineral material, or any combination thereof.

The invention further provides that the tie rails can be solid or 25 tubular metal, plastic, wood, or bamboo or any other rigid material with or without elasticity, that the tie rails can be of square, rectangular, circular, elliptical or any other shaped cross section, and that the tie rails can be straight, curved, offset, or at an angle to each other, whatever geometry is apt for the deployment of 30 the mesh.

The invention further provides that the tie rails can be flexible material, such as stout cable or cord, held tautly or with controlled sag between purling.

The invention is further explained, by way of example, by the following description, taken in conjunction with the appended

drawings, in which: s Figure 1 is an isometric oblique view, from beneath, of a typical industrial roof, apt for the application of the present invention.

Figures 2A to 2C are side views of the three stages of creating a safety net according to the present invention.

Figures 3A to 3C are the same three stages as shown in Figures 2A to 2C, but this time looking in the direction of the arrow A in Figure 2A. 15 Figures 4A to 4C also show the same three stages as are shown in Figures 2A to 2C and in Figures 3A to 3C, but this time shown from below, looking in the direction of arrow B in Figure 2C.

Figure 5 shows how a tie rail can be attached to a purlin using one 20 or more exemplary tie rail clamps.

And Figure 6 shows how the light mesh and the heavy mesh can be slit and 25 re-attached around an obstruction.

Attention is first drawn to Figure 1, showing an isometric oblique view, from beneath, of a typical industrial roof, apt for the application of the present invention.

A roof 10 comprises a roof skin 12 supported on a plurality of spaced purlins 14 which, in turn, are supported on a lesser plurality of steel support members 16, the steel support members 16 being, generally, at right angles to the spaced purlins 14, and the 35 steel support members 16 being generally of greater strength than the spaced purlins 14. The purlins 14 and the steel support members

16 are here shown as both being H section steel bars, though the shape and material can vary, and can include concrete, other metals, timber and timber derivatives, and plastics. The present invention is apt for use with any such variation.

As an example, skylights 18 are provided through the skin 12 of the roof 10, and the example given of the invention relates to provision of a safety net to prevent tools and individuals falling through a skylight 18. It is to be understood that the present invention is 10 applicable to other situations, including, but not exclusively, thin roof skins 12 through which falling is possible, and apertures in a roof 10.

Typically, obstructions 20, here shown in the form of a dependent 15 light, litter the roof 10 line, and can also include pillars, electric cabling, pneumatic supply lines, steam lines, instrumentation lines and water pipes.

Attention is next drawn to figures 2A, 3A and 4A, all showing a 20 first stage in the deployment of a safety net, according to the present invention.

A tie rail 22 is attached to a purlin 14 by means of a tie rail clamp 24 which grips the tie rail 22 in a circular tie rail holder 25 26 through which the tie rail 22 passes. The tie rail 22 can be attached to a purlin by many other means, which can, non exclusively, include welding, binding or tying with cord, gluing, and screw fixings, and by any other means capable of attaching a tie rail to a purlin.

Attention is next drawn to figures 2B, 3B and 4B, all showing a second stage in the deployment of a safety net, according to the present invention.

35 A fine mesh net 28 is spread between the tie rails 22, extending to overlap the area occupied by the skylight 18, being attached, in

this preferred embodiment, to the tie rails by tie wraps 30, spaced at intervals along each tie rail 22, and each passing through an edge portion of the fine mesh net 28. For preference, the fine mesh net 28 is provided substantially taut between the tie rails 22, but 5 the present invention also encompasses the fine mesh net 28 being permitted a degree of controlled sag.

In this preferred embodiment the fine mesh net 28 is attached to the tie bars 22 by tie wraps 30. It is to be appreciated that the fine 10 mesh net 28 can be attached to the tie bars 22 by other means, these including (not to the exclusion of any others), welding, light cord, light clamps, light clips, light hooks and catches.

The purpose of the fine mesh net 28 is to prevent passage downwards 15 of tools and other items that might be dropped. The fine mesh net 28 can be polymer, natural fibre, metal (including steel), ceramic or mineral material, or any combination thereof. The fine mesh can consist in, or can incorporate, plastic film material suitable for preventing, arresting and decelerating falling individuals or 20 objects.

Attention is next drawn to figures 2C, 3C and 4C, all showing a third and final stage in the deployment of a safety net, according to the present invention.

A heavy mesh net 32 is spread between the tie rails 22, extending to overlap the area occupied by the skylight 18, being attached by, in this preferred embodiment, to the tie rails 22 by stout cord 34, wrapped along each tie rail, and passing through an edge portion of 30 the heavy mesh net 34. For preference, the heavy mesh net 32 is provided substantially taut between the tie rails 22, but the present invention also encompasses the heavy mesh net 32 being permitted a degree of controlled sag.

35 In this preferred embodiment the heavy mesh net 32 is attached to the tie rail 22 by stout cord. It is to be appreciated that the

heavy mesh net 32 can be attached to the tie bars 22 by other means, these including (not to the exclusion of any others),heavy cord, heavy clamps, heavy clips, heavy hooks and substantial catches.

5 The purpose of the heavy mesh net 32 is to prevent passage downwards of one or more individuals who might fall through the roof 10, skylight 18, or otherwise find themselves in a falling hazard. The heavy mesh net 32 can be polymer, natural fibre, metal (including steel), ceramic or mineral material, or any combination thereof.

Attention is next drawn to figure 5, showing how a tie rail can be attached to a purlin using one or more exemplary tie rail clamps 24.

The tie rail 22 can be attached to a purlin 14 by means of one or 15 more tie rail clamps 24 each of which comprise a C-clamp section 36 firmly screwable to one side of a purlin 14 by a C-clamp bolt 38. A tie rail holder 40, in the form of a circular ring. is welded beneath the C-clam section 36. The tie rail 22 passes through and is supported by the tie rail holder 40, optionally be in prevented from 20 horizontal slippage by a tie rail bolt 42. Figure 5 shows just one way in which a tie rail 22 can be affixed to a purlin 14.

Finally, attention is drawn to Figure 6, which shows how the light mesh and the heavy mesh can be slit and re-attached around an 25 obstruction.

The fine mesh net 28 is shown by way of example in Figure 6. Exactly the same measures are applied to the heavy mesh net 32.

30 The fine mesh net 28 is dealt with rather in the manner that floor coverings and carpets are dealt with. The light mesh net 28 is first slit along a portion of its length, to pass by the obstruction 20, as indicated by arrow 44. The fine mesh net 28 is then parted, as indicated by arrows 46, and passed around the obstruction 20. The 35 split parts of the fine mesh net 28 are then brought together again, on the far side of the obstruction, as indicated by arrows 48, thus

bypassing and surrounding the obstruction 48. Finally, the split edges of the fine mesh net 28 are bound together again, on the far side of the obstruction, using cord 50, or any other means whereby the strength of the fine mesh net 28 can be substantially restored 5 or bettered, also including (not to the exclusion of any other means) clips, clamps, sewing and stapling.

The meshes 28 32 can be additionally secured to the tie rails 22 by 10 wrapping a portion of the mesh 28 32 around the tie rail 22 and back onto the mesh 28 32 between the tie rails 22, the extended flap of mesh being affixed optionally onto the tie rail 22 but also being tied, bound, sewn or lashed onto the adjacent mesh material between the tie rails 22. The binding medium can be bungee cord, climbing 15 rope or similar material to give a degree of elasticity to the attachment. The meshes 28 32 can also be of similar material to allow for controlled deceleration of objects and individuals.

The edge attachments 30 34 for the mesh 28 32 can be given a degree 20 of freedom to slide so that displacement of the mesh 28 32 can be controllably decelerated. Alternatively, the attachments 30 34 for the mesh 28 32 to the tie rails 22 can be made non-slipping by tightness, or by providing fixed clamps and obstructions on each tie rail 22 to stop displacement of the attachments 30 34.

The tie rails can be solid or tubular metal, plastic, wood, or bamboo or any other rigid material with or without elasticity.Tthe tie rails can be of square, rectangular, circular, elliptical or any other shaped cross section, the tie rails can be straight, 30 curved, offset, or at an angle to each other, whatever geometry is apt for the deployment of the mesh. Another alternative allows the tie rails 22 to be flexible material, such as stout cable or cord, held tautly or with controlled sag between purling.

The tie rails 22 can leave a gap between the mesh 28 32 and the roof skin 12 where an individual or object could roll through or through which an individual or object, obliquely moving, could directly fall. In order to prevent this, screen or barrier portions can be 5 applied between the tie bars 22 and the roof skin 12, filling or nearly filling the gap to prevent such risks. The screen or barrier portions can be attached to the tie bars 22, the purlins 14, the steel support members 16, the roof skin or any other suitable place.

The screen or barrier members can any material, or any composite 10 material, and can include (not to the exclusion of any other materials) fibre, metal (including steel) meshes, nets wire netting and solid materials such as sheet metal, wood or polymers/plastics.

The invention, as described, is applicable to temporary 15 installations, and also applicable to permanent installations where the option of employing rigid material meshes and welded or bolted construction become most attractive.

Claims

1 A safety net system for a roof, where a roof skin is supported on purling, said system comprising: a first tie rail; first tie rail attachment means to attach said first tie rail to two or more purling; a second tie rail, spaced from said first tie rail; second tie rail attachment means to attach said second tie rail to said two or more purling; and a mesh, for suspension between said first tie rail and said second tie rail.

2 A system, according to claim 1, wherein the mesh comprises a first light mesh for attachment to the first and second tie rails using light attachment means, and wherein the light attachment means comprises at least one of cable tie wraps, light cord, light clamps, light clips, light hooks and catches.

3 A system, according to claim 2, wherein the light mesh is capable of stopping tools or other items falling.

4 A system, according to any one of claims 1 to 3, wherein the mesh comprises a second heavy mesh for attachment to the first and second tie rails using heavy attachment means, and wherein the heavy attachment means comprises at least one of heavy cord, heavy clamps, heavy clips, heavy hooks and substantial catches.

5 A system, according to claim 4, wherein the heavy mesh is capable of stopping one or more individuals falling.

6 A system, according to claim 4 or claim 5, wherein the light mesh has a lighter form and finer pitch than the heavy mesh.

7 A system, according to any one of claims 4 to 6, comprising means to overcome an obstruction including slitting the light e ae À Àe. À À À e e e a À e ee e À e À À e e.

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mesh and/or the heavy mesh to allow the slit mesh to pass around the obstruction, the slit in the mesh being made good by re-attaching the edges of the slit together.

8 A system, according to claim 7, wherein the re-attaching of the slit edges is achieved by at least one of cord, welding, clamps and clips.

9 A system, according to any one of the preceding claims, wherein the tie rails are attached to the purlins by tie rail clamps, wherein each tie rail clamp comprises clamp means for attaching the tie rail clamp to the purlin, and wherein each tie rail clamp comprises a tie rail holder, attached to the tie clamp to support the tie rail beneath the purlin.

10 A system, according to any one of the preceding claims, wherein a tie rail is supported beneath a purlin by means of at least one of welding, binding or tying with cord, gluing and using screw fixings.

A system according to any one of the preceding claims, wherein the first mesh comprises at least one of polymer, natural fibre, metal (including steel), ceramic or mineral material, and any combination thereof.

12 A system, according to any one of claims 4 to 8, or according to any one of claims 8 to 11 when dependent upon claim 4, wherein the heavy mesh comprises at least one of polymer, natural fibre, metal (including steel), ceramic or mineral material, or any combination thereof.

13 A system, according to any one of the preceding claims, wherein the tie rails comprise at least one of solid and tubular metal, plastic, wood and bamboo.

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14 A system, according to any one of the preceding claims, wherein the tie rails have a cross section comprising at least one of square, rectangular, circular and elliptical.

15 A system, according to any of the preceding claims, wherein the tie rails have a shape including at least one of straight, curved, offset and at an angle to each other.

16 A system, according to any one of the preceding claims, wherein the tie rails are of flexible material, including at least one of stout cable or cord, held tautly or with controlled sag between purling.

A method for providing a safety net system for a roof, where a roof skin is supported on purling, said method comprising the steps of: providing a first tie rail; attaching said first tie rail to two or more purling; providing a second tie rail, spaced from said first tie rail; attaching said second tie rail to said two or more purling; employing a mesh for preventing falling; and suspending said mesh between said first tie rail and said second tie rail.

18 A method, according to claim 17, including the steps of providing, as said mesh, a first light mesh for attachment to the first and second tie rails using light attachment means, and providing that the light attachment means comprise at least one of cable tie wraps, light cord, light clamps, light clips, light hooks and catches.

19 A method, according to claim 18, wherein the light mesh is capable of stopping tools or other items falling.

20 A method, according to any one of claims 17 to 19, including the step of providing a second heavy mesh for attachment to the first and second tie rails using heavy attachment means, and providing that the heavy attachment means comprise at .... À. À À À

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least one of heavy cord, heavy clamps, heavy clips, heavy hooks and substantial catches.

21 A method, according to claim 20, wherein the heavy mesh is capable of stopping one or more individuals falling.

22 A method, according to claims 20 or 21, wherein the light mesh has a lighter form and finer pitch than the heavy mesh.

23 A method, according to claims 20, 21 or 22, including the step of overcoming an obstruction by slitting the light mesh and/or the heavy mesh to allow the slit mesh to pass around the obstruction, the slit in the mesh being made good by re attaching the edges of the slit together.

24 A method, according to claim 23, including re-attaching the slit edges by at least one of welding, clamps and clips.

25 A method, according to any one of the preceding claims, including the step of attaching the tie rails to the purlins by tie rail clamps, each tie rail clamp comprising clamp means for attaching the tie rail clamp to the purlin, and a tie rail holder, attached to the tie clamp to support the tie rail beneath the purlin.

26 A method, according to any one of claims 17 to 25, including the step of supporting the tie rail beneath a purlin by means of at least one of welding, binding with cord, gluing and using screw fixings.

27 A method, according to any one of claims 23 to 26, for use where the first mesh comprises at least one of polymer, natural fibre, metal (including steel), ceramic or mineral material and any combination thereof.

28 A method, according to any one of claims 17 to 24, or according to any one of claims 24 to 27 when dependent upon ......

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claim 23 wherein the heavy mesh comprises at least one of polymer, natural fibre, metal (including steel), ceramic or mineral material and any combination thereof.

29 A method, according to any one of claims 17 to 28, for use where the tie rails comprise at least one of solid or tubular metal, plastic, wood, or bamboo or any other rigid material with or without elasticity.

30 A method, according to any one of claims 17 to 29, wherein the tie rails are of square, rectangular, circular, elliptical or any other shaped cross section.

31 A method, according to any one of claims 17 to 30, wherein the tie rails are straight, curved, offset, or at an angle to each other.

32 A method, according to any one of claims 17 to 31, wherein the tie rails are of flexible material, such as stout cable or cord, held tautly or with controlled sag between purling.

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