GB2575240A

GB2575240A - Walkway apparatus

Info

Publication number: GB2575240A
Application number: GB1807761.0A
Authority: GB
Inventors: Thomas Neil
Original assignee: Nature Walks Pty Ltd
Current assignee: Nature Walks Pty Ltd
Priority date: 2018-05-14
Filing date: 2018-05-14
Publication date: 2020-01-08
Also published as: AU2018205063A1; GB201807761D0

Abstract

A walkway 2 mounted to a surface comprises a plurality of support portions 6, at least one tunnel portion 14 and a walkway portion 20. The tunnel portion is connected between a pair of the support portions and comprises a plurality of interconnected tensile members placed under tension. The walkway may be mounted on a cliff. Tensioning devices (18, Figure 6) connect the tensile members to a support portion such that larger axial displacement of tensile members relative to the support portions occurs when tension in the tensile member exceeds a predetermined value, allowing extension of the tensile member in cases such as rock falls. The tensioning device may include at least one tension spring. The tensile member may separate from the support portion if tension exceeds a second predetermined value. A plurality of tensioning devices may connect the tunnel portion to the support portion. At least one support portion may be pivotably mounted to the support surface at a first location and mounted by at least one tensile member 10 at a second location. The walkway may be mounted to the support portion by at least one hinged support.

Description

WALKWAY A P PARATUS.

The present, invention relates to a walkway apparatus for mounting to a support surface, and relates particularly, 5 but not exclusively, to a walkway apparatus adapted to be mounted to a cliff.

Walkways attaches to outdoor n.r.faces such as cliffs also suffer from the disadvantage that if a large rock should 10 fall onto the walkway, the rapid application of deceleration forces to the rock causes large reaction forces to be applied to the walkway. This can cause damage to the walkway, and in extreme cases can cause the walkway to become detached from the outdoor surface.

Preferred embodiments of the present invention seek co overcome one or more of the above disadvantages of the prior art.

According to the present invention, there is provided a walkway apparatus adapted to be mounted to a support surface and to enable persons to walk along a path defined by the apparatus, the apparatus comprising:25 a plurality of support portions adapted to be mounted, to the support surface;

at least one tunnel portion adapted to be connected between a respective pair of adjacent said support portions, 30 wherein the or each said tunnel portion comprises a respective plurality of interconnected tensile members adapted to be placed under tension to define a shape of the tunnel portion;

-2a walkway portion adapted to be located in at least one said tunnel portion and to extend between at least one said pair of adjacent said support members; and tensioning means adapted to connect at least one said tensile member to a said support portion such that larger axial displacement of said tensile member relative to said support portion occurs when tension in said tensile member exceeds a first predetermined value.

By providing tensioning means adapted to connect at least one tensile member to a support portion such that larger axial displacement of the tensile member relative to the support portion occurs when tension in the tensile member exceeds a first predetermined value, this provides the advantage of providing a relatively robust structure m normal use (i.e. when the tension in the tensile member is below the first predetermined value), but allows extension of the tensile member' in the event of an unusually large load being applied to the tunnel portion, such as falling roc.< m the case of a walkway apparatus mounted to a cliff surface. This in turn provides the advantage of lowering the rate at which deceleration forces are applied to an object falling onto the tunnel portion, thereby reducing the level of the reaction forces applied to the tunnel portion. In addition, displacement of the tensile member enables an object applying a load to the tunnel portion to apply load to other tensile members, thereby distributing the applied load among other tensile members of the tunnel portion, thereby reducing uhe likelihood of failure of any single tensile member.

-3The tensioning means may include at least one tension spring.

At least one said tensile member may be aaapted to separate from the corresponding support portion if tension applied thereto exceeds a second predetermined value.

This provides the advantage o.t preventing catastrophically large loads from being transmitted to several support portions and detaching the support portions from the support surface, thereby limiting tne extent of failure of the apparatus.

The tensioning means may comprise a plurality or tensioning devices adapted to connect the tunnel portion no the support portion at a plurality of locations.

This provides the advantage of distributing the load through several locations, thereby reducing tne likelihood of 20 failure of the apparatus.

At least one said support portion may οε pivotably mounted to the support surface at at least one respective first location, and may be mounted by means or at least one 25 tensile members at a respective second location.

The walkway portion may be mounted to the support portion by means of at least one hinged support.

A preferred embodiment of the invention will now be described, by way of example only.

and not in any limitative sense with reference to the accompanying drawings in which:~4~

Figure 1 is a front view of a walkway apparatus embodying the present invention mounted to a cliff;

Figure 2 is

Figure n internal view of the apparatus of view from below of apparatus of

Figure uppert and t

Figures 5A to bC are schematic views from above of part of the apparatus of Figure 1 showing changes in dimensions with changes in temperature;

Figure

5D is a cross sectional e line

D-D in

Figure

5E view along the line

Figure 6 is a schematic cross sectional, view along the line F-F in Figure 7 through the connection of the tunnel portion to the support portion in Figure 5A;

Figure 7 is a schematic side view of the junction of Figure. 6;

Figure 7A is a detailed view of a tensioning device of Figure 7; and

Figures 8A to 8E show operation of the tensioning device of Figure 7A.

Referring to Figures 1 to 4, a walkway apparatus 2 embodying the present invention is mounted to a support surface in the form of a cliff 4. The walkway apparatus 2 comprises support portions 6, each of which is pivotaoly mounted (Figure 5D) to the cliff surface 4 at a respective first location 8 and supported by tensile cables 10 mounted 10 to the cliff surface 4 at respective second locations 12.

Adjacent pairs of support portions 6 are connected by turmei portions 14 formed from meshes of tensile members 16 formeo from polyethylene material displaying negative thermal expansion, for example polyethylene material sold under the trade mark Dyneema®. The meshes 14 are mounted to the support portions 6 under tension via tensioning means in the form of tensioning devices 18 (Figures 6 and ’) at a plurality of locations around the circumference of tne end of each mesh 14. The apparatus 2 also includes a waxkwcsy portion 20 within the tunnel portions 14 for enabling persons to walk along a path defined by the apparatus 2. The walkway portion 20 is mounted to each of the support portions 6 by means of hinged support struts 22 (Figure 5D) and to tensile members 16 of the tunnel portions 14 via support struts 24 (Figure 4).

Referring to Figures 6 and 7, pairs of tensile members 16 of the tunnel portions 14 are mounted at several locations around the circumference of the tunnel portions 14 to respective tensioning devices 18, Each tensioning device 18 has a housing 24 containing a tension spring 26 which applies a tension to a pair 28 of joined rensile members 16 of the mesh 14. When the tension applied to tne tension spring 26 reaches a desired level, an abutment plate 30 is fixed to the tensile member 16 connected to the string 26 and abuts an end face 32 of the housing 24 to maintain the tension in the spring 26, as shown in Figures 8A and 8B. As the level o.t tension applied to the tensile member 16 connected to the spring 26 increases above a first predetermined value, the tension in the tensile member 16 cable becomes sufficiently large to extend the tension spring 26 and separate the abutment, plate 30 from the end face 32 of the housing 24 as shown in Figure 81'3. As the tension applied to the tensile member 16 increases further, the tensile member 16 is designed to break at a controlled location 34, wnen the tension in the tensile member 16 exceeds a second predetermined level, to separate tne tensile member 16 iron the support portion 6.

The operation of the apparatus 2 will now be described.

Tn normal use of the apparatus 2, the tension applied to the tensile members 16 of the runnel portions 14 by rhe tensioning devices 18 is relatively constant, which maintains the shape of the tunnel portions 14. As the ambient temperature reduces, the length of the support portions 6, in an axial direction of the tunnel portions 14, decreases, while the length of the tunnel portions 14 increases because of the negative thermal expansion of the tunnel portions 14. In the event of normal use of the apparatus 2, external forces such as wind applied to the tunnel portions 14 do not cause the tension in the tensile members 16 to exceed the pretension applied to the tensile members 16 joined to the tensioning devices 18, as shown in Figures 8C.

-7In the event of significant forces being applied to the tunnel portions 14, for example as a result of a large rook falling onto a tunnel portion 14, the tension applied to the tensile member 16 attached to the tensioning device 18 nearest to the location of impact of the rock becomes sufficiently large to separate the abutment plate 30 from the end face 32 of the housing 24, as a result of which the tensile member 16 extends, thereby increasing tne rime over which decelerating forces are applied to the rock. This in turn reduces the overall level of force applied by the rock on the tunnel portion 14 and vice versa. At the same time, as the tensile member 16 extends, it is displaced by rhe falling rock, which in turn applies forces to other tensile members 16 connected to other tensioning devices 16, thereby distributing the forces among other tensioning devices 18.

In the event that a very large force is applied, the tensile member 16 breaks at the controlled location 34 as shown in Figure 8E, to cause the tunnel portion 14 to fail, but preventing the forces from beincj transferred to other parts of the apparatus 2, thereby limiting the failure of the apparatus to a single tunnel portion 14.

It will be appreciated by persons skilled in the art that the above embodiments have been described by way of 25 example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims.

Claims

1. A walkway apparatus adapted to be mounted to a support surface and to enable persons to walk along a path defineo by

5 the apparatus, the apparatus comprising:a plurality of support portions adapted to be mounted to the support surface;

10 at least one tunnel portion adapted to be connected between a respective pair of adjacent said support portions, wherein the or each said tunnel portion comprises a respective plurality of interconnected tensile members adapted to be placed under tension to define a shape of the

15 tunnel portion;

a walkway portion adapted to be located in at least on said tunnel portion and to extend between at least one said pair of adjacent said support members; and tensioning means adapted to connect at least one said tensile member to a said support portion such that larger axial displacement, of said tensile member relative to said support portion occurs when tension in said oensile memoer 25 exceeds a first predetermined value.

2. An apparatus according to claim 1, wherein the tensioning means includes at least one tension spring.

30

3. An apparatus according to claim 1 or 2, wherein at least one said tensile member is adapted to separate trom the corresponding support portion if tension applied thereto exceeds a second predetermined value.

4. An apparatus according to any one of the preceding claims, wherein the tensioning means comprises a plurality of tensioning devices adapted to connect the tunnel portion to

5 the support portion at a plurality of locations.

5. An apparatus according to any one of the preceding claims, wherein at least one said support portion is adapted to be pivotably mounted to the support surface at at least

10 one respective first location, and is adapted to be mounted by means of at least one tensile members at a respective second location.

6. An apparatus according to any one of the preceding

15 claims, wherein the walkway portion is adapted to be mounted to the support portion by means of at least one hinged support.