Helipad safety net

Abstract

A helipad safety net assembly (100) and a method of installing the same are provided. The helipad safety net assembly (100) includes a net (10), at least one stay (22), and an edge line (23). The net (10) is formed of a plurality of strands (24, 25, 26) arranged side-by-side with each other in a longitudinal direction and fastening means (27) connecting adjacent strands (24, 25, 26) at intervals to form meshes (28) of the net (10), wherein end rows (21) of the meshes (28) are formed at two longitudinally opposite edges of the net (10) and longitudinal rows (29) of the meshes (28) are formed at the two longitudinal edges of the net (10). The stay (22) is adapted to pass through a mesh (28) of one of the end rows (21), the edge line (23) is adapted to secure the net (10) within a perimeter frame (12) by loops formed by winding substantially helically around the perimeter frame (12), each loop passing through a mesh (28) of the longitudinal rows (29), through a mesh (28) of the end rows (21) and simultaneously securing the stay (22) to the perimeter frame (12), wherein the at least one stay (22) includes an array of openings (33) through which the edge line (23) can pass to secure an end of the edge line (23). The helipad safety net assembly (100) is easy to install and remove.

Description

Technical Field

[0001] The present invention relates to a safety net for a helipad, which can be arranged on the perimeter of the helipad, for example. Background Art

[0002] In the oil and gas and offshore industries, helicopter access is accommodated via helipads on drilling rigs, ships, and other offshore structures for helicopter takeoff and landing. Helipads are also used on land on buildings and similar elevated structures, where helipad safety nets or perimeter nets contribute to the safety of helicopter operations by preventing and restraining people or objects from falling over the edge of the helipad without causing injury or damage.

[0003] Beyond the fundamental requirement of providing an energy-absorbing structure capable of safely and cost-effectively withstanding the required loads, the harsh environments in which such structures are used necessitate that the mesh system must have a useful life, after which it should be replaced. However, many prior art solutions exhibit features that make the installation and removal of perimeter meshes quite problematic. For example, securing the mesh may require multiple tools or fasteners, which can be time-consuming to install and present a risk of falling, or create localized weaknesses due to stress concentrations. Avoiding welding, which can also pose a fire hazard, is particularly advantageous.

[0004] An object of the present invention is to overcome or substantially ameliorate the above disadvantages, or more generally, to provide an improved helipad safety net. Summary of the Invention

[0005] According to one aspect of the present invention, there is provided a helipad safety net, comprising:

[0006] A net elongated in the longitudinal direction, the net being formed by a plurality of wire bundles arranged side by side with each other in the longitudinal direction and fastening means connecting adjacent wire bundles at certain intervals to form meshes of the net, wherein longitudinal rows of meshes are formed on the longitudinal edges of the net and the longitudinal edges are connected by at least one end edge, wherein end rows of meshes are formed along the at least one end edge,

[0007] at least one strut adapted to pass through the mesh of one of the end rows, and

[0008] a border wire adapted to secure the mesh within the perimeter frame by being wound in loops generally helically around the perimeter frame, each loop passing through the mesh of the longitudinal rows, through the mesh of the end rows and simultaneously through the inside of at least one strut to secure it to the perimeter frame, wherein the at least one strut includes an array of openings through which the border wire can be passed to secure the ends of the border wire.

[0009] Not only is such a helipad safety net easier to install and remove, but it has been found that, under drop testing, the provision of struts according to the invention results in a significantly increased load at which the net initially begins to fail compared to a net secured by edge wires only, and this is believed to be achieved through better load distribution by avoiding the high load harnesses.

[0010] Although the wires forming each harness may comprise ropes or ribbons of natural and / or synthetic fibres, the wires are preferably formed from wire or a similar elastic material to provide bending resilience. In addition, for example, the ropes or ribbons of natural and / or synthetic fibres may be reinforced with wire to provide a wire having bending resilience. In a net of this structure, bending resilience is advantageous because when the wire harness returns to its original, generally straight form, it tends to naturally contract to close the mesh. Advantageously, because the wire harnesses are adjacent to each other, the contracted net forms a bundle that is elongated and compact in the transverse direction and can therefore be wound onto a narrow coil, avoiding the need to fold the net for transport or to wind the net onto a coil corresponding to the full width of the net.

[0011] Preferably, the at least one end edge comprises a pair of longitudinally opposed end edges, each end edge comprising a respective end row of mesh, and the at least one strut comprises a pair of struts, each strut being adapted to pass through the mesh of one of the end rows.

[0012] The net can be formed to fit the perimeter frame and, in particular, can be sized so that, when installed and properly tensioned, the edges of the net are spaced inwardly relative to the perimeter members of the perimeter frame. Typically, the net has straight longitudinal edges that are parallel to one another, which is advantageous for simple net construction, but is not essential, and all edges may be curved.

[0013] Preferably, the metal wires are stranded metal wires, such as twisted metal wires, ie a twisted wire cable or rope.

[0014] Preferably, the securing means comprises a crimp, ferrule, weld or the like which permanently secures the harness.

[0015] Preferably, the wires forming the wire harness and the edge wires have the same configuration.

[0016] Preferably, the brace is tubular. A smooth outer shape is believed to contribute to its performance. In this regard, rectangular or triangular hollow cross-sections, due to their rounded corners, have a sufficiently smooth outer shape and may perform satisfactorily. Alternatively, the brace may be solid material.

[0017] Preferably, the mesh, the edge wires and the struts consist of the same material, in particular of inherently corrosion-resistant steel.

[0018] Preferably, the openings in the array of openings extend transversely across the strut and are axially spaced apart from one another.

[0019] Preferably, the openings are arranged coaxially in pairs in diametrically opposed wall portions of the strut.

[0020] Preferably, the central axis of the opening lies generally in a longitudinal plane bisecting the strut.

[0021] Preferably, a notch is formed in each longitudinally opposite end of the strut, the notch being adapted to receive portions of laterally opposite edges of the mesh to stretch the mesh laterally.

[0022] Preferably, the recess comprises recessed portions in diametrically opposed portions of respective ends of the strut, the axis of the recess being arranged substantially orthogonal to the central axis of the opening.

[0023] Preferably, the helipad safety net further comprises a perimeter of the frame which may comprise outer and inner longitudinal members parallel to each other connected by shorter transversely extending inclined members.

[0024] In another aspect, the present invention provides a method for installing a helipad safety net, the method comprising:

[0025] providing a first net extending in the longitudinal direction, the net being formed by a plurality of wire bundles arranged side by side with each other in the longitudinal direction and a fastening device connecting adjacent wire bundles at regular intervals to form meshes of the net, wherein end rows of meshes are formed at both longitudinally opposite edges of the net, and longitudinal rows of meshes are formed at both longitudinal edges of the net,

[0026] providing a brace having an array of openings;

[0027] Passing the brace through the mesh of one of the end rows, and

[0028] winding the edge wire into loops generally helically around a perimeter frame to secure the net within the perimeter frame, said generally helically winding comprising passing each loop through the mesh of the longitudinal rows, through the mesh of the end rows and simultaneously through the inside of a strut to secure the strut to the perimeter frame, and

[0029] The edge wire is passed through the continuous opening in the opening to secure the ends of the edge wire to the struts. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0031] Figure 1 is a perspective view of an embodiment of a helipad safety net according to the present invention;

[0032] Figure 2 is an enlarged view of a detail of the helipad safety net according to the present invention;

[0033] Figure 3 Shows the formation Figure 2 The structure of the wire harness of the net;

[0034] Figures 4 to 6 is a schematic diagram of an optional configuration of the helipad safety net according to the present invention;

[0035] Figure 7 and Figure 8 is a plan view of an optional support pole for a helipad safety net according to the present invention;

[0036] Figure 9 is fixed to Figure 7 A schematic perspective view of an edge line of one end of a brace;

[0037] Figure 10 is a schematic perspective view of a member having an edge line connected to a frame for supporting a helipad safety net of the present invention;

[0038] Figure 11 is a partial plan view of a single brace used to connect the overlapping edges of two nets in the helideck safety net of the present invention; and

[0039] Figure 12 is a plan view of a pair of struts used to connect the longitudinally spaced edges of two nets in the helipad safety net of the present invention. DETAILED DESCRIPTION

[0040] Reference Figure 1 , a helipad safety net or net assembly 100 is shown installed along one edge of the helipad 11 and secured within a perimeter frame 12. On the octagonal helipad 11 shown, the perimeter frame 12 may extend around all eight sides for holding the safety net 100 around the entire perimeter, with the frame 12 secured to an underlying or adjacent structure (not shown in the drawings). The safety net assembly 100 may be adapted to fit within the perimeter frame 12 and may include a trapezoidal net 10 ( Figure 1Two of the trapezoidal nets 10 are shown in FIG.

[0041] The perimeter of the frame 12 can include similar elongated members 13 and 14, with the inner member 14 arranged along the edge of the helipad 11 and the outer member 13 offset outwardly and generally parallel thereto. Web members 15-20 are relatively short and extend between the inner and outer members 13 and 14 and can be welded to the inner and outer members at their respective ends. The assembly of members 13-20 can be considered a subframe 112, with the constituent members 13-20 generally coplanar and either arranged horizontally or tilted such that the inner and outer members 13 and 14 are horizontal but the outer member 13 is relatively high. Web members 15-20 can be transverse (as in the case of web members 17-20) or tilted (as in the case of web members 15 and 16). The complete frame 12 for the illustrated octagonal helipad 11 can effectively be configured as an assembly of eight subframes 112 joined at their ends (where adjacent subframes 112 share tilted web members 15 and 16). It should be understood that this is by way of example only, and that the perimeter frame 12 need not necessarily take this shape, need not necessarily have straight sides, and may have more or fewer components than shown here.

[0042] Figure 1 The safety net assembly 100 shown includes two nets 10 that together enclose a perimeter frame 12, and both include trapezoidal nets 10 that are elongated in the longitudinal direction. End rows 21 of mesh are formed at two longitudinally opposite transverse edges of each net 10, and two struts 22 are used, each strut 22 being woven through the mesh of a corresponding end row 21.

[0043] The struts 22 and the transverse edges of the mesh 10 are secured by edge wires 23 which are generally helically wound into loops, each loop passing through the mesh 28 of the end row 21 while extending through the inside of the struts 22 and around adjacent web members 15 , 16 and 18 .

[0044] This same edge thread 23 may extend in the form of a loop around the longitudinal members 13 , 14 and through the mesh at the longitudinal edges of the net 10 in order to secure the net 10 to the frame 12 .

[0045] Figure 2 and Figure 3 The preferred structure of the net 10 is shown, which is made of wire, preferably in the form of twisted wire bundles 24, 25, 26, etc. arranged side by side in the longitudinal direction. The nodes of the net 10 are formed by crimps 27 providing a fastening means, which are plastically deformed to connect adjacent bundles 24, 25, 26 in spaced pairs, thereby forming the mesh 28 of the net 10.

[0046] The bending resilience of the wire strands 24, 25, and 26 means that a load must be applied to stretch the mesh 10 and extend the strands to the position shown, where they assume the sinusoidal form shown. In their relaxed state, the strands 24, 25, and 26 tend to be approximately straight, so the mesh 10 has an inherent tendency to contract laterally. Mesh 28 can be formed along the longitudinal edges of the mesh by folding a strand back upon itself, so that a pair of adjacent strands appear integral. For example, strands 25 and 26 are shown as being integral.

[0047] Figure 4 A structure of the net 10 is shown to provide Figure 1 The slanted edge is formed with an edge row 21 of loops or meshes 28, which is inclined relative to the longitudinal edge row 29 and is formed by folding a strand 24, 25, 26 back on itself. Figure 4 Another generally orthogonal edge row 30 is shown comprising mesh 28 which is not formed by folding back the strands, but rather by being closed by crimps 27 provided along the edge.

[0048] In contrast, the inclined edge row 21 does not necessarily comprise a loop formed by folding back a bundle of wires, but can also be formed by connecting individual bundles of wires at the transverse edge by means of a crimp 27, as in Figure 5 shown.

[0049] In fact, all of the strands 24, 25, 26 of the mesh 10 may be integral, i.e., the mesh may be formed using individual strands arranged in a staggered pattern, e.g. Figure 6 This figure also shows how loops or return portions can be provided at both ends of each strand. Of course, while using a single strand to form a strand to make the net can provide advantages, this is not essential to the present invention.

[0050] Figure 7 and Figure 8 Two different examples of struts 22 are shown in FIG, and both struts 22 are preferably tubular for a smooth outer shape.

[0051] The openings 33 for receiving the edge wires 23 are arranged in rows and axially spaced apart from each other. Each opening 33 can be circular and extend transversely through the strut 22, wherein the openings 33 are coaxially arranged in pairs in diametrically opposed wall portions. The central axes of the openings 33 generally lie in a common longitudinal plane that bisects the strut. The openings can be longitudinally spaced equidistantly. The openings 33 can be arranged in two groups, each group adjacent to one longitudinal end (according to the Figure 7 ), or arranged in a single group, close to the middle of the strut 22 (according to Figure 8 ).

[0052] Each of the longitudinally opposite ends of the struts 22 is formed with a notch 34 adapted to receive portions of the laterally opposite edges of the net 10 to laterally deploy the net 10. The notch 34 comprises notched portions at diametrically opposite portions of the respective ends of the struts, and the axis of the notch 34 is generally orthogonal to the axis of the opening 33 lying in a common longitudinal plane bisecting the struts. This arrangement allows the axis of the notch 34 to lie generally in the plane of the installed net, while the axis of the opening 33 is substantially perpendicular to the plane of the installed net 10.

[0053] In use, nets 10 are transported to the installation site in a folded state, where their compact size and low weight are beneficial. To install net 10, a strut 22 is first installed along the mesh 28 of each transverse edge or end row 21, with the strut 22 passing through each mesh 28 in row 21. Then, by inserting each longitudinal edge of net 10 into a corresponding one of the notches 34, the elasticity of net 10 and its tendency to collapse laterally ensure that the strut 22 is securely attached to net 10. Optionally, one end of edge wire 23 can also be secured to one of the struts 22 before being moved to perimeter frame 12.

[0054] Figure 9 The process of fastening the edge wire 23 to the strut 22 is shown, wherein the edge wire 23 is inserted back and forth through the openings 33, thereby providing a high degree of friction to prevent the unwanted release of the wire 23. The wire 23 extends through the rod 22 and a pair of openings 33 before the tightening ring 35 reverses its direction to extend through the next opening 33, which can be adjacent. These steps are then repeated to form four, five or more loops 35. The end 123 of the edge wire 23 can be vertically downward to prevent water from entering. When using an edge wire 23 of a 4 to 7 mm diameter wire bundle coated with a polymer, a satisfactory fixation can be achieved by hand (i.e., without the need for tools) using this method.

[0055] Typically, installation is then completed by placing the struts 22 adjacent to one of the transverse members of the perimeter frame, such as transverse member 16. Loop-type fasteners 36, such as ties, can be used to temporarily secure the edges of the net 10 to the perimeter frame 12. The edge wire 23 is then spirally wound into a loop around the perimeter of the transverse member, passing through each mesh 28 through which the struts 22 themselves extend, and extending through the inside of the struts 22, securely securing it to the inside of member 16. A similar method is used to secure one longitudinal edge of the net 10, whereby the edge wire 23 loops through the mesh 28 at that longitudinal edge.

[0056] If the single edge wire 23 extends around the entire perimeter of the net, then as mentioned above, by looping the wire 23 through the openings 33, the portions of the wire 23 that are opposite the ends of the row 21 can be fixed to the respective struts 22. In this way, each portion is independent, since a break in one portion extending between two sets of openings 33 does not affect the integrity of any other portion, whereby, for example, a single break in the wire 23 cannot allow the entire edge wire 23 to loosen. In order to divide the wire 23 into further independent portions, the portions of the wire 23 that are wrapped around the longitudinal members 13 and 14 can be fixed to these longitudinal members 13 and 14, respectively, for example by fastening rings 31 that are fixed to the edge wire 23 by crimped sleeves 32 or the like, as shown in Figure 10 , where the net 100 is omitted for clarity.

[0057] When the frame 12 is made of a material that is different from the (stainless steel) of the edge wire 23 and the net 100, in order to mitigate the possibility of galvanic corrosion, polymer strips (not shown) can be provided at the interface between the frame 12 and the net 100, for example where the net covers the intermediate members 17, 19 and 20, to prevent contact between the frame 12 and the net 100. Likewise, the net 100 can be fixed inside the inner edges of the frame (for example at approximately 20 mm intervals) to avoid contact with the frame 12.

[0058] The fastening step of the method can have various variations, of course, without it being necessary to fix the single edge wire around the entire perimeter of the frame 12, with both wire ends being fixed to the same strut 22. Advantageously, the use of two edge wires 23 can allow two struts 22 and the respective end of the net to be first fixed to the perimeter frame 12, with the terminal end of each of the two wires being fixed to a respective one of the two struts 22 in the manner described above. Likewise, a single spiral portion of the edge wire 23 can simultaneously fix two struts 22 on opposite sides of a member 18 (of the frame 18 in Figure 1 ).

[0059] Figure 11 and Figure 12 Another way is shown, in which one or more struts 22 can be used to fix the lateral edges of the net, with the struts 22 being used to connect two lateral edges together, in order to connect two overlapping ( Figure 11 ) or longitudinally spaced apart ( Figure 12 ) lateral edges of the net. In this different application, the use of the struts 22 also offers similar advantages in terms of ease of installation and strength, in order to improve the popularity. In Figure 11 and Figure 12 , the adjacent bundles of wires forming the net 10a, 10b are connected by crimping 27, thereby forming the mesh that defines the end row 21 of the lateral edges.

[0060] Figure 11A single strut 22 is shown connecting the two transverse edges together, thereby connecting the two nets 10a, 10b end-to-end. The strut 22 weaves through the mesh of the end row 21 of net 10a, while also weaving through the mesh of the end row 21 of net 10b. The strut 22 is secured in place by effectively connecting both ends to the frame 12 using edge wires 23a, which also serve to secure the longitudinal edges of the net 10a to the adjacent member 113. This is achieved by sequentially threading edge wires 23a through four adjacent openings 33 near the ends of the strut 22, and sequentially threading edge wires 23b through adjacent openings in another set of openings 33 near the ends of the strut 22, thereby providing additional security by securing each end of the strut 22 with two separate wires 23a, 23b.

[0061] like Figure 12 As shown, an alternative arrangement employs a pair of struts 22a, 22b, each of which is woven through the mesh of the end rows 21 of a corresponding one of the two nets 10a, 10b. A border string 23 is then used to connect the pair of struts 22 together by wrapping it spirally around the outsides of the two struts 22. The opposite ends of the border string 23 can be secured to the struts 22 in the manner described above by continuously passing it through openings 36, as shown. A particular advantage of this arrangement is that varying the spacing between the struts 22 provides a method for varying the length of the net.

[0062] The edge lines 23a, 23c used to secure the longitudinal edges of the net 10a to the member 113 can also secure the opposite ends of the strut 22b to the member 113, and correspondingly, the edge lines 23b, 23d used to secure the longitudinal edges of the net 10b to the member 113 can also secure the opposite ends of the strut 22a to the member 114.

[0063] Aspects of the present invention have been described by way of example only, and it will be appreciated that modifications and additions may be made thereto without departing from the scope of the invention.

Claims

1. A helipad safety device comprising: a net elongated in a longitudinal direction, the net being formed by a plurality of wire bundles arranged side by side with one another in the longitudinal direction and fastening means connecting adjacent wire bundles at intervals to form meshes of the net, wherein longitudinal rows of meshes are formed at longitudinal edges of the net, and the longitudinal edges are connected by at least one end edge, wherein end rows of meshes are formed along the at least one end edge; at least one strut adapted to pass through the mesh of one of the end rows; as well as a border wire adapted to secure the mesh within the perimeter frame by being wound in loops generally helically around the perimeter frame, each loop passing through the mesh of the longitudinal rows, through the mesh of the end rows and simultaneously through the inside of at least one strut to secure it to the perimeter frame, wherein the at least one strut includes an array of openings through which the border wire can be passed to secure the ends of the border wire.

2. The helipad safety device according to claim 1, wherein: The at least one end edge comprises a pair of longitudinally opposed end edges, each end edge comprising a respective end row of mesh, and the at least one strut comprises a pair of struts, each strut being adapted to pass through the mesh of one of the end rows.

3. The helipad safety device according to claim 1, wherein: The mesh is formed of metal wires to provide bending elasticity.

4. The helipad safety device according to claim 3, wherein: The metal wire is a multi-strand metal wire.

5. The helipad safety device according to any one of claims 1 to 4, wherein: The fastening means comprises a crimp.

6. The helipad safety device according to any one of claims 1 to 4, wherein: The wires forming the wire harness and the edge wires have the same configuration.

7. The helipad safety device according to any one of claims 1 to 4, wherein: The struts are tubular.

8. The helipad safety device according to any one of claims 1 to 4, wherein: The mesh, the edge wire and the struts are composed of the same material.

9. The helipad safety device according to any one of claims 1 to 4, wherein: The openings in the array of openings extend transversely through the strut and are axially spaced apart from one another.

10. The helipad safety device according to claim 9, wherein: The openings are coaxially arranged in pairs in diametrically opposed wall portions of the strut.

11. The helipad safety device according to claim 9, wherein: The central axis of the opening lies generally within a longitudinal plane that bisects the strut.

12. The helipad safety device according to any one of claims 1 to 4, wherein: A notch is formed at each longitudinally opposite end of the strut, the notch being adapted to receive portions of laterally opposite edges of the net to laterally expand the net.

13. The helipad safety device according to claim 12, wherein: The notch includes notch portions in diametrically opposed portions of respective ends of the strut, the axis of the notch being disposed generally orthogonally to a central axis of the opening.

14. A helipad safety arrangement according to any one of claims 1 to 4, further comprising a perimeter of the frame comprising outer and inner longitudinal members parallel to each other connected by shorter transversely extending inclined members.

15. A method for installing a helipad safety device, the method comprising: providing a first net extending in the longitudinal direction, the first net being formed of a plurality of wire bundles arranged side by side with each other in the longitudinal direction and a fastening device connecting adjacent wire bundles at regular intervals to form meshes of the net, wherein end rows of meshes are formed at both longitudinally opposite edges of the first net, and longitudinal rows of meshes are formed at both longitudinal edges of the first net; providing a brace having an array of openings; Passing the strut through the mesh of one of the end rows; and winding the edge wire into loops generally helically around a perimeter frame to secure the first mesh within the perimeter frame, the generally helically winding comprising passing each loop through the mesh of the longitudinal rows, through the mesh of the end rows and simultaneously through the inside of the struts to secure the struts to the perimeter frame; as well as The edge wire is passed through the continuous opening in the opening to secure the ends of the edge wire to the struts.

16. The method according to claim 15, further comprising: providing a second net extending in the longitudinal direction, the second net being formed of a plurality of wire bundles arranged side by side with each other in the longitudinal direction and a fastening device connecting adjacent wire bundles at regular intervals to form meshes of the net, wherein end rows of meshes are formed at two longitudinally opposite edges of the second net, and longitudinal rows of meshes are formed at two longitudinal edges of the second net; connecting the first of the end rows of the first net to the second of the end rows of the second net by passing a brace through meshes of the first of the end rows of the first net and the second of the end rows of the second net; as well as Opposite ends of the struts are connected to the frame using edge wires that secure adjacent longitudinal rows of mesh to the perimeter frame.

17. The method according to claim 15, further comprising: providing a second net extending in the longitudinal direction, the second net being formed of a plurality of wire bundles arranged side by side with each other in the longitudinal direction and a fastening device connecting adjacent wire bundles at regular intervals to form meshes of the net, wherein end rows of meshes are formed at two longitudinally opposite edges of the second net, and longitudinal rows of meshes are formed at two longitudinal edges of the second net; Passing each of a pair of struts through cells of a corresponding one of the end rows of the first and second nets; as well as To connect the first and second nets, a wire is wrapped in a spiral fashion around the outside of the pair of struts.

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