|
(11) | EP 0 889 178 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | A support system |
| (57) A support system for supporting a user over a void comprises a first layer (1) of
a flexible material; and means (4) for securing the first layer under tension to a
fixed structure, the arrangement being such that when the first layer (1) is secured
to the fixed structure and placed under tension the system forms a temporary platform
which is capable of supporting the weight of a user and of providing him with freedom
to move over the platform whilst being so supported. A second layer (2) acts as a
safety net and is separately secured to a fixed structure. An intermediate layer (2)
of finer mesh acts to prevent detritus from working operation from falling to the
ground. |
[0001] This invention relates to a support system for use for example in the construction industry for supporting a workman whilst working above a supporting surface such as the ground.
[0002] In the construction industry workmen are often required to work at a height above a void, for example at a height within a building or structure or over a pit. During, for example, the erection of large warehouses or buildings made from metal girders securely fastened by bolts or other fastenings a great deal of the work has to take place at a height above ground level. In order to allow personnel to reach the point of work and remain there safely while work is carried out it is necessary to erect scaffolding or use some other mechanical access device. Such conventional methods are expensive to use or put in place and in some cases, depending on the particular construction being carried out or the shape or use of the building upon which work is being carried out, may be impractical or impossible to use. In addition high level work involves a risk to personnel working at the elevated point of work and also to those below who are in danger of being hit by either falling personnel or objects falling from above. Although the use of safety nets and debris collecting nets is known, for example as described in GB-A-2228036 and US 5582266, these have merely been capable of preventing dropped objects from falling to the ground or of breaking the fall of personnel. They still require the use of conventional scaffolding having all of the disadvantages outlined above.
[0003] There is, therefore, a need for a versatile means of providing access to an elevated point of work, which is easy and cheap to assemble and which may be used in instances where access for conventional scaffolding is not available or would be too expensive. The present invention meets that need as is described in detail below.
[0004] According to the present invention there is provided a support system for supporting a user over a void, which work support system comprises:
a first layer of a flexible material; and
means for securing the first layer under tension to a fixed structure,
the arrangement being such that when the first layer is secured to the fixed structure and placed under tension the system forms a temporary platform which is capable of supporting the weight of a user and of providing him with freedom to move over the platform whilst being so supported.[0005] The material from which the first layer is made and the construction of that layer may take any suitable form which allows the layer when placed under tension to be capable of supporting a person's weight. In addition they should allow the layer to be lightweight and easily portable. The material and construction is preferably such that the reaction of the first layer under load is one of elastic deformation. In such a case the first layer can be reversibly tensioned and slackened. Suitable materials include sufficiently strong yet elastic pure or composite metallic or plastics materials or woven or non-woven fabrics and combinations of those materials. The first layer may be made of a single material or formed from several layers of different materials. The material may be in the form of a continuous sheet, for example, of either woven or non-woven material, but more preferably the material is in the form of a net. The net may be knotted or preferably knotless in structure and the cords or fibres from which the net is formed may be of a single or composite material. Preferably the cords are greater in diameter than those from which conventional construction industry safety nets are formed, e.g. they are greater than 4mm, more preferably 5mm or greater in diameter.
[0006] The first layer may be provided with an edge member for strengthening it along its edges. Such an edge member is particularly preferred for longitudinal edges of the layer. The edge member may take the form of a sheath enclosing a part of the edge of the layer. Where the first layer is in the form of a net the edge member may enclose several of the longitudinal cords from which the net is formed. Such an edge member is preferably such as to increase the stiffness of the first layer particularly at its edges allowing it to respond well to pretensioning and perpendicular loading. The edge member may also be of assistance in the securing of the first layer to a structure.
[0007] The support system of the present invention preferably additionally comprises:
a second layer of a flexible material, and
means for securing the second layer to a structure, the arrangement being such that in use with the first layer in tension the second layer is suspended below the working platform to form a safety barrier.
[0008] The second, or safety barrier layer may be a component of the system which is separate from the first, or platform layer or it may be attached to the first, or platform layer at one or more positions so that they form a single or integral component of the system. The second, or safety barrier layer and the first, or platform layer may be joined at discrete positions, preferably in their peripheral regions, or they may be joined continuously around their entire peripheries.
[0009] The second layer is preferably of substantially the same external shape as the first layer. The second layer should, however, be of greater dimensions than the first layer so that when the first layer is placed under tension the second layer is not in tension to the same degree but is suspended with play below the platform thus formed and is able to carry out its safety function, i.e. able to check the fall of heavy objects or workman falling from above in the event of failure of the first layer. It has been found that to allow both layers to perform their function best it is advantageous that the safety barrier layer be between 10 per cent and 5 per cent greater in area than the area of the first or platform layer.
[0010] The means by which the second or safety barrier layer may be secured to the structure may be those by which the platform layer is so attached, i.e. they may share the securing means. They may directly or indirectly share those means. If, for example, the two layers were attached to one another, securing means provided on one of the layers could indirectly be used to secure the other layer. Although the two layers could be secured to the structure at the same places and by the same means, if either the securing means or the structure to which the layers are secured fails in some way, both layers would be affected by that failure. It is, therefore, preferred that the safety barrier layer is independently secured to the structure so that if a failure of the securing means of the platform layer or of the structure to which the platform layer is secured occurs for some reason the safety barrier will remain securely fastened. A workman on that platform would then fall to the waiting safety barrier below. The safety barrier layer can be independently secured to the structure whether or not it is attached to the platform layer, so that even in an integral system it can serve as a safety back up in case of the type of failure outlined above.
[0011] The material from which the safety barrier layer may be formed and its construction may be any material and construction suitable for carrying out the required safety function, in other words any material whose strength and construction is such as to be able to support a falling person's weight and break their fall. The material and construction is preferably such that the reaction under load of the second or safety barrier layer is substantially exclusively one of plastic deformation. That deformation may take place in the material itself (such as is required for a knotless safety net) or in the construction (such as by tightening of knots in a knotted safety net). In either case the layer is capable of absorbing the energy of a falling object with minimal bounce. The second layer is preferably capable of withstanding a force of up to 6kN. The materials described above as being suitable for the platform layer would also be suitable for the barrier layer and those two layers may be made from the same or different materials and have the same or different constructions. Any safety net, for example those conventionally used in the construction industry, may be used for the manufacture of the safety barrier layer. Such conventional safety nets may, for example, be formed from nylon mesh. It is, however, preferred that the safety barrier layer be made from the same material as that used for the platform layer and for that material to be substantially identical in construction.
[0012] The support system of the present invention preferably also comprises:
a third layer of flexible material, and
means for securing the third layer to a structure, the arrangement being such that in use with the first layer in tension the third layer is suspended below the working platform to form a debris collector.
[0013] In use it is preferred that the debris collector is above the safety barrier and situated directly below the working platform so that an object dropped onto the debris collector can be retrieved by personnel on the platform.
[0014] The debris collector layer may be a component separate from both the platform layer and the safety barrier layer or it may be attached to one or both of those layers. In one embodiment of the present invention all three layers are attached to each other so that they form an integral component. The attachment of the layers may be at discrete positions or continuously around their peripheries.
[0015] The debris collector layer is preferably of substantially the same external shape as the platform layer. It may be of substantially the same size as that layer as well, but it is preferred that it is of greater dimension than the platform layer so that when the platform layer is placed under tension the debris collector is not in tension to the same degree but is suspended slightly below the platform and is able to carry out its debris collecting function, i.e. it is able to prevent the fall of small (but heavy) objects, such as nuts and bolts or shavings of building materials and the like, from falling to the ground below. The debris collector layer is preferably about 10 per cent, more preferably 5 per cent, greater in area than the area of the platform layer.
[0016] It is preferred that the debris collector layer is substantially the same or smaller in size than the safety barrier layer.
[0017] The means by which the debris collector layer may be secured may be the same as those for the platform layer.
[0018] As described above in relation to the safety barrier layer the securing means may be shared directly or indirectly and the debris collector layer may be independently or dependently secured to the structure.
[0019] Materials suitable for use in the manufacture of the debris collector layer are as given above for the other layers of the system. As the requirements of the debris collector layer are not as great as those for the other layers, a lower specification, cheaper material may be used for its manufacture. The material merely needs to be able to collect small falling objects and if possible prevent them from falling further below. Any known debris collector net, such as those conventionally used in the construction industry, may be used, e.g. a fine mesh debris collector net or tarpaulin.
[0020] The individual layers of the support system of the present invention may be attached to each other as described above by any conventional means, e.g. by sewing, lashing, staples or any other conventional fastening or attachment means. The layers may be joined by each being attached to a border piece extending along a part or all of the periphery of the layers. Again the layers may be attached to such a border piece by any conventional means. The border piece may take any suitable form.
[0021] The securing means by which the system is secured in place for use may take any conventional form. Those means may secure the system directly onto a structure or indirectly via a fastening means itself secured to the structure by suitable and conventional means. Fastening means secured to the structure, e.g. ropes, hooks, clasps or clamps, may be fastened onto one or more of the layers. Such fastening may take place via securing rings or the like provided on the layers. Alternatively fastening may be through the structure of the layers themselves, in particular when the layers are formed from a net or mesh structure or a specific fabric weave. In this case the securing means is a part of the layers themselves and not a separate component. A preferred example of this is where the fastening means takes the form of a cord or rope which is woven in and out of the holes in the net. Such a cord may extend along one or more of the edges of the net, e.g. along its longitudinal edges, or more preferably around the whole border or periphery of the net. A single fastening rope may be used to secure one or two or all three of the layers. Tie ropes or cords are fastened to the or each fastening rope to secure the layer or layers to the structure. Suitably high tensile rope, cables and other means for fastening and securing the system will be well known to the skilled man. Any fastening rope used to secure the first layer should be able to take and distribute the load applied to the platform. It preferably is able to take a force of at least 30kN. It is also preferred that any fastening rope for the safety barrier forming layer is also able to withstand such a force. The positioning of the securing means may be varied according to the particular use required for the system. The system may, for example, be secured at discrete locations distributed around the periphery of the layers. They are preferably positioned so as to distribute the load evenly over the working platform. Either additionally or in place of securing the system around its periphery the system may be secured at places within the interior of the layers. The shape of the working platform can be varied by variation in the positions at which the system is secured to the structure.
[0022] The overall size and shape of the system according to the present invention will depend on the nature of the working platform required and the dimensions and shape of the structure in which working is to take place. The system is inherently versatile allowing the shape of the platform to be varied in use depending upon its points of securement. In addition different systems having layers of different size and shape can be manufactured. Further, when required two systems, e.g. two platform forming layers, can be joined together to form a larger system.
[0023] The present invention is advantageous as it provides an easily assembled, easily removable, temporary, portable workstation which allows personnel to work at a height over a void. Its flexible nature allows it to be used in circumstances where scaffolding may not be possible due to the particular size and shape of the structure in which work is to be carried out. It is also cheaper and easier to erect than conventional scaffolding and mechanical access devices. Its ease of transportation and assembly allows the use of a high level working platform in more locations than previously possible. In addition its flexibility allows it to be fitted into odd shaped or sized areas and provide a work platform covering the whole of the floor area of a structure or simply a part of that area. In addition it is easily movable around within that area. The working platform provided by the present invention is safe for personnel, even those working at a considerable height. In addition preferred embodiments of the invention guard those below against falling tools, building materials or the like and provide a safety barrier to prevent personnel from falling to the ground.
[0024] For a better understanding of the present invention, and to show how the same may be put into effect, reference will now be made, for purposes of illustration only, to the accompanying drawings in which:
Figure 1 is a perspective view of a first embodiment of a work support system according to the present invention;
Figure 2 is a side view of that embodiment;
Figure 3 is a perspective view of a second embodiment of the present invention; and
Figure 4 is a side view of the second embodiment.
[0025] The work support system shown in Figure 1 comprises a substantially rectangular working platform 1 formed from a flexible material held in tension. Below the working platform 1 is suspended a debris collecting net 2 also of substantially rectangular shape. The debris collecting net 2 is of greater area than the working platform 1 and is therefore not at the same tension and is suspended a little way below the working platform 1. Below both the working platform 1 and the debris collecting net 2 is suspended a safety net 3. The safety net 3 is also of substantially rectangular shape but is greater in area than either the working platform 1 or the debris collecting net 2 and is therefore suspended further below them both. The working platform 1, the debris collecting net 2 and the safety net 3 are all stitched together around their perimeters to a border piece 4. Connection or securing rings 5a, 5b, 5c, 5d, are provided at the corners of the working platform 1 around the border piece 4. Fastening ropes or ties 6a, 6b, 6c, 6d, are attached to those securing rings 5a, 5b, 5c, 5d at one end and to girders 7a, 7b of the building in which the working platform is being used at the other end. The safety net 3 is independently secured to another pair of girders 8a, 8b by means of further securing rings 9a, 9b, and fastening ropes 10a, 10b. The independent securing of the safety net 3 allows it to act as a safety barrier if the other means of securing the system fail. Additional securing rings 11 are situated within the area of the working platform and may be used to vary its size and shape, or to tension it to various other support members.
[0026] The fastening ropes 6a, 6b, 6c, 6d are used to tie the composite net at a suitable tension to the surrounding structure to allow personnel to walk on the working platform 1. The working platform 1 is of 10 metre by 5 metres in area. The safety net 3 and the debris collecting net 2 are 5-10 per cent larger in area than the working platform 1, which is therefore rigged at a greater tension in use than those lower nets. The working platform 1 is formed of a 5mm diameter high tensile, multifilament polypropylene cord, 45mm knotless square net. The debris collecting net 2 is a fire retardant fine mesh debris net and the safety net 3 is of similar specification as the working platform 1 but is of a 100mm mesh net made from 4.5mm diameter mutifilament polypropylene with a cord strength of 2.6kN breaking strain. The border piece 4 is formed from 11.2 mm three strand nylon rope tested to 30kN breaking strain. The fastening ties are 2 metre long and of the same specification as the border piece to which it is attached at preferably 0.75 metre intervals.
[0027] A second embodiment of the present invention is shown in Figures 3 and 4. It is similar to that shown in Figures 1 and 2 save that the working platform 12, the debris collector 13 and the safety net 14 are separate components. The platform 12 has a fastening rope 15 interwoven through the mesh of its net around its periphery close to its edge. It is secured to a part of the structure 16 by tie ropes 17 which pass around the fastening rope 15, pass around the part of the structure 16 and are then securely knotted. The length of the tie ropes 17 can be shortened to increase the tension in the platform 12. The safety net 14 has its own fastening rope 18 around its border by which further tie ropes 19 attach it to the part of the structure 16. The fastenings and tie ropes are all capable of withstanding a force of 30kN. The debris collector 13 is secured simply by cable ties (not shown). The embodiment is shown with tie ropes positioned every 0.5m along the length of the platform. The rigging is tight to the structure to eliminate as far as possible any gaps occurring between adjacent ties.
1. A support system for supporting a user over a void, which work support system comprises:
a first layer of a flexible material; and
means for securing the first layer under tension to a fixed structure,
the arrangement being such that when the first layer is secured to the fixed structure and placed under tension the system forms a temporary platform which is capable of supporting the weight of a user and of providing him with freedom to move over the platform whilst being so supported.2. A support system according to Claim 1, which additionally comprises:
a second layer of a flexible material, and
means for securing the second to a fixed structure, the arrangement being such that in use with the first layer under tension the second layer is suspended below the platform thus formed to form a safety barrier.
3. A support system according to Claim 2, wherein the first layer and the second layer
are joined to each other so as to form a single component of the system.
4. A support system according to Claim 2 or 3, wherein the second layer is greater in
area than the area of the first layer.
5. A support system according to Claim 4, where the second layer is between 5 percent
and 10 per cent greater in area than the first layer.
6. A support system according to any one of Claims 1 to 5, which additionally comprises:
a third layer of flexible material, and
means for securing the third layer to a structure, the arrangement being such that in use with the first layer in tension the third layer is suspended below the platform thus formed to form a debris collector.
7. A work support system according to Claim 6, wherein, the first layer, the second layer
and the third layer are joined together to form a single component.
8. A method of providing a support system capable of supporting a user above a void,
which method comprises:
placing under sufficient tension a first layer of flexible material capable, when under sufficient tension, of supporting the weight of a user so as to form a temporary platform; and
securing the tensioned layer to a structure.
9. A method according to Claim 8, which additionally comprises providing a safety barrier
below the working platform and independently securing the safety barrier to the structure.
10. A method according to Claim 9, which additionally comprises providing a debris collector
between the working platform and the safety barrier.
11. A support system substantially as hereinbefore described with reference to, and as
illustrated in, Figure 1 of the accompanying drawings.
12. A method of providing a support system substantially as hereinafter described with
reference to and as shown in the accompanying drawings.