AU2021236429A1

AU2021236429A1 - Step Definition System

Info

Publication number: AU2021236429A1
Application number: AU2021236429A
Authority: AU
Inventors: William Small
Original assignee: Small William Karl
Current assignee: Small William Karl
Priority date: 2021-09-20
Filing date: 2021-09-20
Publication date: 2023-04-06

Abstract

A step and walkway definition system; said system including attachment of edge defining indicating elements; said elements configured for attachment to edge defining structural elements of a said step or walkway and, wherein the edge defining elements are yellow or green in colour and include a textured surface. In another broad form of the invention, there is provided a stair tread indication element; the element adapted for attachment proximate a leading edge of the stair tread; the stair tread indicating element extending at least part way for a width of the stair tread; the stair tread indicating element finished in a high visibility colour. 3/14 Figure 5

Description

3/14

Figure 5

STEP DEFINITION SYSTEM TECHNICAL FIELD

[0001] The present invention relates to safety devices and systems and, more particularly, to safety indicators for use in factories and like environments.

BACKGROUND

[0002] Many factories and industrial installations have operational requirements involving steps up to platforms and walkways, sometimes at many levels, above the factory floor or ground level. Typically, both steps and walkways are open structures in that their walk-on surfaces are comprised of spaced apart elements, for example expanded mesh or lattices. While this construction saves weight and construction costs, as well as minimising obstruction to lighting, such steps and walkways can be disorienting and their edges sometimes difficult to see clearly. This is especially true of multiple levels of steps and walkways where levels become difficult to distinguish to persons walking on a higher level who can see levels below through the open structure.

[0003] A further and a separate problem is that there may not be sufficient grip exhibited by open structure stairs and walkways.

[0004] It is an object of the present invention to address or at least ameliorate some of the above disadvantages.

Notes

[0005] The term "comprising" (and grammatical variations thereof) is used in this specification in the inclusive sense of "having" or "including", and not in the exclusive sense of "consisting only of'.

[0006] The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.

SUMMARY OF INVENTION

[0007] Accordingly in one broad form of the invention there is provided a step and walkway definition system; said system including attachment of edge defining indicating elements; said elements configured for clip-on attachment to edge defining structural elements of a said step or walkway.

[0008] Preferably said steps and walkways comprise open lattice structures in factories and industrial installations.

[0009] Preferably said indicating elements are finished in a colour strongly contrasting with structural steel finishes of said open lattice structures.

[00010] Preferably the colour is green.

[00011] Preferably the colour is yellow.

[00012] Preferably the colour comprises light reflected from the edge defining indicating elements in the range 500 to 600 nanometres.

[00013] Preferably the colour comprises light reflected from the edge defining indicating elements in the range 550 to 560 nanometres.

[00014] Preferably each of said indicating elements is formed as an elongate element; each said elongate element having a narrow inverted U-shaped cross-section; said element comprising a base portion and opposing side walls extending from said base element.

[00015] Preferably said opposing side walls are symmetrical about a central plane of said indicating element; said opposing side walls angling inward towards said central plane from said base portion so that portions of said side walls distal from said base portion are proximate one to the other.

[00016] Preferably lowermost portions of said opposing side walls are angled outwardly relative said central plane; said lowermost portions angled outwardly from a narrowest region between said sidewalls, so that lowermost edges of said side walls are separated to a greater extent than separation between said walls at said narrowest region.

[00017] Preferably said side walls are of sufficient length so as to position said narrowest region below a lower edge of an edge element of said step or walkway when said indicating element is installed for use.

[00018] Preferably inner surfaces of said side walls are provided with inwardly projecting lugs proximate said narrowest region; said inward projecting lugs preventing dislodgement of a said indicating element once installed for use.

[00019] Preferably said base portion of said indicating element is provided with a series of transverse slots; said transverse slots providing a reduction in rigidity of said base portion so as to provide for flexure of said base portion and outward flexure of said side walls relative said central plane.

[00020] Preferably portions of said side walls form upward extensions extending past said base portion; said upward extensions located at the sides of said transverse slots.

[00021] Preferably said extensions prevent contact of user footwear or other objects with surfaces of said base portion.

[00022] Preferably said indicating elements are formed of metal.

[00023] Preferably said strongly contrasting colour is applied as a powder coating.

[00024] Preferably said indicating elements are injection moulded of a polymer material; said strongly contrasting colour inherent in said polymer material.

[00025] Preferably said strongly contrasting colour is yellow.

[00026] In yet a further broad form of the invention there is provided a method of indicating edges of steps and walkways in factories and industrial installations; said method including the step of attaching indicating elements of a strongly contrasting colour at selected locations along said edges.

[00027] Preferably the colour is green.

[00028] Preferably the colour is yellow.

[00029] Preferably the colour comprises light reflected from the edge defining indicating elements in the range 500 to 600 nanometres.

[00030] Preferably the colour comprises light reflected from the edge defining indicating elements in the range 550 to 560 nanometres.

[00031] Preferably said elements clip onto said edges.

[00032] Preferably said elements are elongate with a generally narrow inverted U-shaped cross section.

[00033] In a further broad form of the invention there is provided a step and walkway definition system; said system including attachment of edge defining elements; said elements configured for clip-on attachment to edge defining structural elements of a said step or walkway.

[00034] In a further broad form of the invention there is provided a step and walkway definition system; said system including attachment of edge defining elements; said elements configured for clip-on attachment to edge defining structural elements of a said step or walkway.

[00035] Preferably said steps and walkways comprise open lattice structures in factories and industrial installations.

[00036] Preferably said elements include an abrasive surface which aids grip of footwear thereon.

[00037] Preferably said abrasive surface includes upwardly projecting elements.

[00038] In yet a further broad form of the invention there is provided a method of improving grip of edges of steps and walkways in factories or industrial installations; said method including the step of attaching elements which aids grip of footwear thereon.

[00039] Preferably said elements clip onto said edges.

[00040] Preferably said abrasive surface includes upwardly projecting elements.

[00041] Preferably opposing side walls of said indicating elements when in use are disposed on either side of edge members of open lattice structure steps and walkways.

[00042] In a further broad form of the invention, there is provided a stair tread indication element; the element adapted for attachment proximate a leading edge of the stair tread; the stair tread indicating element extending at least part way for a width of the stair tread; the stair tread indicating element finished in a high visibility colour.

[00043] Preferably the colour is green.

[00044] Preferably the colour is yellow.

[00045] Preferably the colour comprises light reflected from the edge defining indicating elements in the range 500 to 600 nanometres.

[00046] Preferably the colour comprises light reflected from the edge defining indicating elements in the range 550 to 560 nanometres.

[00047] Preferably, stair treads comprise open lattice structures in factories and industrial installations.

[00048] Preferably, the element has a cross section in form of an "L"; a shorter portion of the "L" fitting over a vertical face of the stair tread.

[00049] Preferably, the length of the longer portion of the "L" extends over a greater part or over complete depth of the stair tread.

[00050] Preferably, the element has a cross section in form of an inverted shallow channel; the channel adapted for installation on a forward portion of the stair tread.

[00051] Preferably, the element has a cross section of arcuate form adapted for installation on a forward portion of the stair tread.

[00052] Preferably, the element is provided with at least two holes; the holes adapted to receiving bolts passing through the element to an underside of the stair tread when the element is placed in position on the stair tread.

[00053] Preferably, the element is secured to the stair tread by the bolts passing through respective brackets located at the underside of the stair tread.

[00054] Preferably, the brackets are shaped to at least partially nest between adjacent ribs of the open lattice structure of the stair tread.

[00055] Preferably, the brackets are provided by threaded holes; the brackets supplied with self locking nuts.

[00056] Preferably, the brackets are provided with clearance holes; the brackets supplied with self-locking nuts.

[00057] In a further broad form of the invention, there is provided a method of heightening visibility of an edge of an industrial stair tread; the method including the steps of: - Forming elongate elements adapted for affixing proximate a forward portion of the stair

tread;

- Finishing the elongate elements in high visibility colours;

- Providing the elongate elements with element securing clips, bolts and nuts;

- Placing the elongate element in position at the forward portion of the stair tread;

- Securing the elongate element to the stair tread.

[00058] Preferably the colour is green.

[00059] Preferably the colour is yellow.

[00060] Preferably the colour comprises light reflected from the edge defining indicating elements in the range 500 to 600 nanometres.

[00061] Preferably the colour comprises light reflected from the edge defining indicating elements in the range 550 to 560 nanometres.

[00062] Preferably, the elongate element is secured to the tread by passing securing bolts through holes provided in the elongate element to extend to below an underside of the stair tread.

[00063] Preferably, the elongate element is secured by brackets and nuts at the underside of the stair tread; holes in the brackets brought into alignment with the bolts passing through the holes in the elongate element.

[00064] Preferably, the elongate element is of an angle cross section; a shorter web of the angle fixed against a vertical face of the stair tread.

[00065] Preferably, the elongate element is of an inverted channel cross section.

[00066] Preferably, the elongate element is of an arcuate cross section.

[00067] Preferably, colours of the elongate elements are applied as applications of coats of resin/paint; an aggregate applied to the resin/paint followed by further coats of resin/paint.

[00068] Preferably, colours of elongate elements formed of fibreglass are provided by pigmentation of resins bonding the fibreglass.

[00069] Preferably, colours of injection moulded indicating elements are provided by injection moulding with coloured polymer powder.

BRIEF DESCRIPTION OF DRAWINGS

[00070] Embodiments of the present invention will now be described with reference to the accompanying drawings wherein:

[00071] Figure 1 is a side view of a preferred embodiment of an indicating element of a step definition system according to the invention;

[00072] Figure 2 is a top view of the indicating element of Figure 1;

[00073] Figure 3 is an end view of the indicating element of Figures 1 and 2;

[00074] Figure 4 is an end view of the indicating element assembled over an edge defining element of a step or walkway;

[00075] Figure 5 is a perspective view of a pair of the indicating elements of Figures I to 3 in use;

[00076] Figure 6 is a perspective view of a first preferred indicating element of a second embodiment of the invention;

[00077] Figure 7 is a perspective view of a section of stairs to which a first preferred indicating element of figure 6 has been assembled to each stair tread;

[00078] Figure 8 is a perspective view of a second preferred indicating element of the second embodiment of the invention;

[00079] Figure 9 is a perspective view of a section of stairs to which a second preferred indicating element of figure 8 has been assembled to each stair tread;

[00080] Figure 10 is a perspective view of a third preferred indicating element of the second embodiment of the invention;

[00081] Figure 11 is a perspective view of a section of stairs to which a third preferred indicating element of figure 10 has been assembled to each stair tread;

[00082] Figure 12 is a perspective view of a fourth preferred indicating element of the second embodiment of the invention;

[00083] Figure 13 is a perspective view of a section of stairs to which a fourth preferred indicating element of figure 12 has been assembled to each stair tread;

[00084] Figure 14 is a perspective view of a bracket by means of which each of the indicating elements of the second embodiment may be secured to a stair tread;

[00085] Figure 15 is a perspective view of a portion of an underside of a stair tread to which an indicating element has been secured by the brackets of figure 14.

[00086] Figure 16 is a visibility graph of the step definition system according to the invention.

DESCRIPTION OF EMBODIMENTS First Preferred Embodiment

[00087] With reference to Figures 1 to 4, the system of the present invention includes the attachment of edge defining indicating elements to edge structural elements of a step or walkway in a factory or industrial installation.

[00088] So as to provide maximum visual impact and thereby alert users to the edge of a step or walkway in the form of an open lattice structure, the indicating elements of the invention are finished in a colour, preferably a bright yellow or green, which strongly contrasts with that typical of structural steel finishes. Factory and industrial step and walkway structures are frequently of galvanised iron and the grey colour of this material can be difficult to distinguish clearly, particularly in the subdued lighting high above a factory floor.

[00089] In a preferred embodiment, an indicating element 10 according to the invention, is formed as an elongate structure, preferably about 85mm in length and 40mm in depth, having a narrow inverted U-shaped cross-section 12, as best seen in the end view of Figure 3. It includes a base portion 13 and opposing side walls 14 and 16 extending from the base portion 13.

[00090] The opposing side walls 14 and 16 are symmetrical about a central plane 18, with the opposing side walls angling inwards from the base portion 13, towards the central plane 18, so that portions 20 and 22 of the side walls, distal from the base portion 13, are closer together.

[00091] As again can best be seen in the end view of Figure 3, the lowermost portions 24 and 26 of the opposing side walls 14 and 16 are angled outwardly relative the central plane 18, from the narrowest region (at 20/22) between the sidewalls. Thus the lowermost edges 28 and 30 of the side walls are separated to a greater extent than the separation between the side walls at the narrowest region.

[00092] As can be seen from the end view of Figure 4, the side walls are of sufficient length so as to position the narrowest region below a lower edge 32 of an edge element 34 of a step or walkway when the indicating element is installed for use. Indicating elements may be provided with different depths to accommodate various structural step and walkway elements in common use.

[00093] Preferably, the inner surfaces of the side walls 14 and 16 are provided with inwardly projecting lugs 36 and 38 proximate the narrowest region 20/22. These inwardly projecting lugs 36 and 38 prevent dislodgement of an indicating element once installed for use, by clipping under the edges of structural element 34. Lugs may be punched and pressed from the side walls in case of a metal construction of the indicating element, or be moulded as part of an injection moulded process.

[00094] As best seen in the plan view of Figure 2, the base portion 13 of the indicating element is provided with a series of transverse slots 40. These transverse slots 40 provide a reduction in rigidity of the base portion 13 so as to provide for flexure of the base portion and outward flexure of the side walls 14 and 16 relative to the central plane 18.

[00095] With reference now to the side view of Figure 1 and the end view of Figure 3, portions of side walls 14 and 16 form upward extensions 42 extending somewhat past the upper surface of base portion 13. The upward extensions 42 are located at the sides of the transverse slots 40. By extending above the upper surface of base portion 13, these upward extensions prevent contact of user footwear or other objects with the surfaces of the base portion, and thereby prevent possible loss of the contrasting colour (if not inherent in the material of the element) and loss of at least a part of the safety function of the element 10. In addition the upward extensions 42 may provide anti-slip properties to the steps.

[00096] The indicating element 10 may be formed of metal, in which case the contrasting colour may be applied as a powder coating for example. Alternately it could be injection moulded from a suitable polymer in which case the colour will be inherent in the material.

Further Embodiments

[00097] In this second preferred embodiment, with references to figures 6 and 7, an indicating element 100 of this embodiment comprises an elongate length of material adapted to extend the greater part or the full length of a leading edge 102 of a stair tread 104. As for thefirst preferred embodiment above, the indicating elements of these further embodiments are also provided in high visibility colours, preferably High Vis Nano555, preferably either yellow and green.

[00098] In addition, the upper surfaces are textured to present a non-slip surface to boots as these step onto the indicating elements.

[00099] In a first preferred arrangement, as shown in figure 6, the indicating element 100 is "L" - shaped, or of angle cross section with the shorter portion 106 or web of the angle fitting against the vertical face 108 of a stair tread 104, and the longer horizontal portion 107 flush against the ribs 109.

[000100] Ina second preferred arrangement as shown in figure 8, the indicating element 110 is formed in section as a shallow, inverted "U" - shaped channel which lends itself to installation on the forward horizontal portion 112 of a stair tread 104, as shown in figure 9.

[000101] In a third preferred arrangement as shown in figure 10, the indicating element 114 has an arcuate section adapted again for installation on a forward portion 112 of a stair tread 104 as shown in figure 11.

[000102] In a fourth preferred arrangement as shown in figure 12, the indicating element 116 is again of "L" - shaped section, but in this instance the longer portion 118 of the "L" is such as to extend the greater part or the complete depth of the surface of a stair tread 104. Indicating element may be provided with securing holes 122 through either or both of the surfaces of the "L" shaped section, to allow securing to either the front plane of a step or to its horizontal surface.

[000103] In each of these further embodiments, the indicating elements are secured in position on a stair tread by means of a bracket 120 such as shown in figure 14. Each of the indicating elements is provided with at least two spaced-apart holes 122 adapted to receive, preferably round headed bolts 124. These are of a length to extend below an underside of the stair tread 104 to engage with brackets 120 which are either provided with a threaded hole or captive nut, or with a clearance hole 128 as shown in figure 14, and supplied with a locking nut 126 as shown in figure 15.

[000104] Preferably, the bracket is shaped as can be seen in figure 14 to partially nest between adjacent ribs 130 of typical industrial steel grid stair treads 104, to prevent any movement which may result from heavy impacts.

[000105] Alternatively, indicating elements of the invention maybe secured by adhesives, for example when desired to apply to concrete steps for example.

[000106] Each of the "L", inverted "U" and arcuate indicating elements maybe formed or moulded of extruded, pressed or roll formed metal or polymer. In an alternative form, the metal may be extruded, pressed or roll formed. In the case of injection moulded indicating elements, green resin powder is used. Alternatively, in metal, indicating elements may be roll formed. Alternatively, in metal, indicating elements may be folded. For metal forms, the colour is applied as coatings of resins/paint, with an anti-slip aggregate applied on the upper surface followed by further applications of paint to lock in the aggregate. Alternatively, an aggregate is applied to resin.

[000107] The indicating elements described above may also be formed of fibreglass. In that case, colour is provided by adding colour pigmentation to the resin used to bond the fibreglass.

In Use

[000108] In use, in the case of the first preferred embodiment, a number of the indicating elements of the invention may be clipped at intervals along the edges, usually leading edges of steps and at least the edge at the entry of a walkway accessed from the steps. Additionally, they may be placed along the long edges of walkways to add to the visibility of these edges.

[000109] The indicating elements of the further embodiments, provide an even more obvious indication of the edges of industrial stair treads. As well, by extending over the greater portion or the full width of the tread and provided with the combination of high visibility colour and texture, they considerably increase the safety of a flight of industrial stair treads.

[000110] By these means, users will have a clear indication of the edges of steps in particular, which will be an aid in avoiding injury from missteps due to poor visibility of these edges, often experienced in factory and industrial installation environments.

[000111] The above describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention.

Claims

CLAIMS 1. A step and walkway definition system; said system including attachment of edge defining indicating elements; said elements configured for attachment to edge defining structural elements of a said step or walkway and, wherein the edge defining elements are yellow or green in colour and include a textured surface.
2. The system of claim 1 wherein said steps and walkways comprise open lattice structures in factories and industrial installations.
3. The system of claim 1 or 2 wherein said indicating elements are finished in a colour strongly contrasting with structural steel finishes of said open lattice structures.
4. The system of claim 3 wherein the colour is green.
5. The system of claim 3 wherein the colour is yellow.
6. The system of claim 3 wherein the colour comprises light reflected from the edge defining indicating elements in the range 500 to 600 nanometres.
7. The system of claim 3 wherein the colour comprises light reflected from the edge defining indicating elements in the range 550 to 560 nanometres.
8. The system of any one of claims 1 to 7 wherein each of said indicating elements is formed as an elongate element; each said elongate element having a narrow inverted U-shaped cross-section; said element comprising a base portion and opposing side walls extending from said base element.
9. The system of claim 8 wherein said opposing side walls are symmetrical about a central plane of said indicating element; said opposing side walls angling inward towards said central plane from said base portion so that portions of said side walls distal from said base portion are proximate one to the other.
10. The system of claim 9 wherein lowermost portions of said opposing side walls are angled outwardly relative said central plane; said lowermost portions angled outwardly from a narrowest region between said sidewalls, so that lowermost edges of said side walls are separated to a greater extent than separation between said walls at said narrowest region.
11. The system of claim 10 wherein said side walls are of sufficient length so as to position said narrowest region below a lower edge of an edge element of said step or walkway when said indicating element is installed for use.
12. The system of claim 10 or 11 wherein inner surfaces of said side walls are provided with inwardly projecting lugs proximate said narrowest region; said inward projecting lugs preventing dislodgement of a said indicating element once installed for use.
13. The system of any one of claims 8 to 12 wherein said base portion of said indicating element is provided with a series of transverse slots; said transverse slots providing a reduction in rigidity of said base portion so as to provide for flexure of said base portion and outward flexure of said side walls relative said central plane.
14. The system of claim 13 wherein portions of said side walls form upward extensions extending past said base portion; said upward extensions located at the sides of said transverse slots.
15. The system of claim 14 wherein said extensions prevent contact of user footwear or other objects with surfaces of said base portion.
16. The system of any one of claims 1 to 15 wherein said indicating elements are formed of metal.
17. The system of claim 16 wherein said strongly contrasting colour is applied as a powder coating.
18. The system of any one of claims 1 to 15 wherein said indicating elements are injection moulded of a polymer material; said strongly contrasting colour inherent in said polymer material.
19. The system of any one of claims 1 to 18 wherein said strongly contrasting colour is yellow.
20. A method of indicating edges of steps and walkways in factories and industrial installations; said method including the step of attaching indicating elements of a strongly contrasting colour at selected locations along said edges.
21. The method of claim 20 wherein the colour is green.
22. The method of claim 20 wherein the colour is yellow.
23. The method of claim 20 wherein the colour comprises light reflected from the edge defining indicating elements in the range 500 to 600 nanometres.
24. The method of claim 20 wherein the colour comprises light reflected from the edge defining indicating elements in the range 550 to 560 nanometres.
25. The method of any one of claims 20 to 24 wherein said elements clip onto said edges.
26. The method of any one of claims 20 to 25 wherein said elements are elongate with a generally narrow inverted U-shaped cross-section.
27. The method of any one of claims 20 to 26 wherein opposing side walls of said indicating elements when in use are disposed on either side of edge members of open lattice structure steps and walkways.
28. A step and walkway definition system; said system including attachment of edge defining elements; said elements configured for clip-on attachment to edge defining structural elements of a said step or walkway.
29. The system of claim 28 wherein said steps and walkways comprise open lattice structures in factories and industrial installations.
30. The system of claim 28 or claim 29 wherein said elements include an abrasive surface which aids grip of footwear thereon.
31. The system of claim 30 wherein said abrasive surface includes upwardly projecting elements.
32. A method of improving grip of edges of steps and walkways in factories or industrial installations; said method including the step of attaching elements which aids grip of footwear thereon.
33. The method of claim 32 wherein said elements clip onto said edges.
34. The method of claim 32 or claim 33 wherein said abrasive surface includes upwardly projecting elements.
35. A stair tread indication element; the element adapted for attachment proximate a leading edge of the stair tread; the stair tread indicating element extending at least part way for a width of the stair tread; the stair tread indicating element finished in a high visibility colour.
36. The element of claim 35 wherein the colour is green.
37. The element of claim 35 wherein the colour is yellow.
38. The element of claim 35 wherein the colour comprises light reflected from the edge defining indicating elements in the range 500 to 600 nanometres.
39. The element of claim 35 wherein the colour comprises light reflected from the edge defining indicating elements in the range 550 to 560 nanometres.
40. The element of any one of claims 35 to 39 wherein stair treads comprise open lattice structures in factories and industrial installations.
41. The element of any one of claims 35 to 40 wherein the element has a cross section in form of an "L"; a shorter portion of the "L" fitting over a vertical face of the stair tread.
42. The element of any one of claims 35 to 41 wherein the length of the longer portion of the "L" extends over a greater part or over complete depth of the stair tread.
43. The element of any one of claims 35 to 40 wherein the element has a cross section in form of an inverted shallow channel; the channel adapted for installation on a forward portion of the stair tread.
44. The element of any one of claims 35 to 40 wherein the element has a cross section of arcuate form adapted for installation on a forward portion of the stair tread.
45. The element of any one of claims 35 to 44 wherein the element is provided with at least two holes; the holes adapted to receiving bolts passing through the element to an underside of the stair tread when the element is placed in position on the stair tread.
46. The element of claim 45 wherein the element is secured to the stair tread by the bolts passing through respective brackets located at the underside of the stair tread.
47. The element of claim 46 wherein the brackets are shaped to at least partially nest between adjacent ribs of the open lattice structure of the stair tread.
48. The element of any one of claims 45 to 47 wherein the brackets are provided by threaded holes; the brackets supplied with self-locking nuts.
49. The element of any one of claims 45 to 47 wherein the brackets are provided with clearance holes; the brackets supplied with self-locking nuts.
50. A method of heightening visibility of an edge of an industrial stair tread; the method including the steps of: - Forming elongate elements adapted for affixing proximate a forward portion of the stair tread; - Finishing the elongate elements in high visibility colours; - Providing the elongate elements with element securing clips, bolts and nuts; - Placing the elongate element in position at the forward portion of the stair tread; - Securing the elongate element to the stair tread.
51. The method of claim 50 wherein the colour is green.
52. The method of claim 50 wherein the colour is yellow.
53. The method of claim 50 wherein the colour comprises light reflected from the edge defining indicating elements in the range 500 to 600 nanometres.
54. The method of claim 50 wherein the colour comprises light reflected from the edge defining indicating elements in the range 550 to 560 nanometres.
55. The method of any one of claims 50 to 54 wherein the elongate element is secured to the tread by passing securing bolts through holes provided in the elongate element to extend to below an underside of the stair tread.
56. The method of any one of claims 50 to 55 wherein the elongate element is secured by brackets and nuts at the underside of the stair tread; holes in the brackets brought into alignment with the bolts passing through the holes in the elongate element.
57. The method of any one of claims 50 to 56 wherein the elongate element is of an angle cross section; a shorter web of the angle fixed against a vertical face of the stair tread.
58. The method of any one of claims 50 to 56 wherein the elongate element is of an inverted channel cross section.
59. The method of any one of claims 50 to 56 wherein the elongate element is of an arcuate cross section.
60. The method of any one of claims 50 to 59 wherein colours of the elongate elements are applied as applications of coats of resin/paint; an aggregate applied to the resin/paint followed by further coats of resin/paint.
61. The method of any one of claims 50 to 60 wherein colours of elongate elements formed of fibreglass are provided by pigmentation of resins bonding the fibreglass.
62. The method of any one of claims 50 to 61 wherein colours of injection moulded indicating elements are provided by injection moulding with coloured polymer powder.