United States Patent r191
`Connew
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,998,391
`Mar. 12, 1991
`
`[54] STRUCTURAL ELEMENT
`
`[75]
`
`Inventor: Raymond A. Connew, Colchester,
`England
`
`[73] Assignee: Shinebuild Limited, Suffolk, England
`
`[21] Appl. No.:
`
`399,472
`
`[22] PCT Filed:
`
`Feb. 22, 1988
`
`PCT/GB88/00107
`[86] PCT No.:
`Oct. 11, 1989
`§ 371 Date:
`§ 102(e) Date: Oct. 11, 1989
`
`[87] PCT Pub. No.: W088/06218
`PCT Pub. Date: Aug. 25, 1988
`
`Foreign Application Priority Data
`[30]
`Feb. 23, 1987 [GB] United Kingdom ................. 8704111
`
`Int. CJ.s .............................................. E04F 15/00
`[51]
`[52] U.S. Cl •......................................... 52/179; 52/181
`[58] Field of Search ......................... 52/177, 179, 181;
`428/98, 917
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`4,522.861 6/1985 Dunsworth .
`4,625,266 11/1986 Winter .............................. 52/188 X
`4,858,404 8/1989 Schluter ................................ 52/179
`Primary Examiner-David A. Scherbel
`Assistant Examiner-Creighton Smith
`Attorney, Agent, or Firm-Watson, Cole, Grindle &
`Watson
`[57]
`ABSTRACT
`Device for mounting on the tread (1) of a step of a
`staircase which comprises a generally planar member
`adapted to be mounted upon or adjacent the leading
`edge of the horizontal portion (the tread) of a step of a
`staircase and extending rearwardly over part or all of
`the width of the step, which rearwardly extending por(cid:173)
`tion of the member is provided with a strip (14) of pho(cid:173)
`toluminescent material. The invention also provides a
`flooring grade sheet plastic containing a photolumines(cid:173)
`cent material suitable for use in the device of the inven(cid:173)
`tion.
`
`5 Claims, 2 Drawing Sheets
`
`13
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`14
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`Page 1 of 7
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`ELASCO EX. 1008
`Elasco v. Checkers
`U.S. Patent No. 7,943,851
`
`

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`U.S.· Patent
`
`Mar. 12, 1991
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`Sheet 1of2
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`4,998,391
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`Figure 1 ,
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`Figure 2
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`Page 2 of 7
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`U.S.·Patent
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`Mar. 12, 1991
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`Sheet 2 of 2
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`4,998,391
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`20
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`Figure 3
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`14
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`31
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`Figure 4
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`Figure 5
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`Page 3 of 7
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`1
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`STRUCTURAL ELEMENT
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`4,998,391
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`The present invention relates to a structural element,
`notably to a stair tread fitting having a photolumines- 5
`cent element thereto, and to a material for use therein.
`
`20
`
`BACKGROUND TO THE INVENTION:
`Stairs often present hazards to users, notably when
`they are poorly lit or not lit at all, for example when the 10
`lighting to a staircase well fails in whole or in part. It
`has therefore been proposed to apply a stripe of lumi(cid:173)
`nescent paint to the riser of each of the steps of the
`staircase, which strip will glow in the dark and give the
`user a guide as to the location of each step. However, 15
`such a method can not be applied where the steps are to
`be carpeted. Furthermore, the paint stripe can only be a
`temporary solution to the problem, since it is readily
`scuffed and removed by the soles of users feet or shoes
`during normal use of the staircase.
`It has also been proposed to apply a stip of self-adhe(cid:173)
`sive plastic tape to the stair riser. However, the edge of
`the strip is readily torn during use of the staircase lead(cid:173)
`ing to removal of the strip and a potential safety hazard.
`The above problems with paints or adhesive tapes 25
`would be aggravated if they were applied to the hori(cid:173)
`zontal tread of the step rather than to the vertical riser,
`since the abrasion and scuffing action of users shoes or
`feet is much larger. On the other hand, another problem
`with paint and tapes applied to the riser of the stair is 30
`that they are not readily visible to users of the stairs
`from above and they do not glow brightly for pro(cid:173)
`longed periods. We believe that this is due to the fact
`that they are mounted on the vertical face which is
`obscured to a person descending the staircase and is a 35
`face onto which only a small amoqnt of direct light falls
`during normal illumination of the staircase.
`It has been proposed to fix a strip of a flexible plastic
`edging strip incorporating a photoluminescent material
`across the step at the apex of its nose. The photolumi- 40
`nescent material was formed as a bead protruding from
`the edging strip so that it would be visible to users both
`ascending and descending the staircase. However, this
`position exposes the material to the maximum abrasion
`and wear during normal use of the staircase. Further- 45
`more, it was found that the light emitted from the pho(cid:173)
`toluminescent material rapidly became obscured. It is
`believed that this was because the material into which
`the photoluminescent material was incorporated was of
`a porous nature and that it readily picked up dirt which 50
`became firmly imbedded therein, thus reducing the
`effect of the photoluminescent material.
`It has been found that the above problems can be
`reduced if the photoluminescent material is incorpo(cid:173)
`rated into a generally planar member having an abrasion 55
`resistant exposed face mounted upon the horizontal
`tread of the stair and having a metal or similar protec(cid:173)
`tive means along its leading edge.
`By mounting the photoluminescent material in a sub(cid:173)
`stantially horizontal position, the present invention en- 60
`sures that it will receive the maximum activation from
`any overhead lighting source and hence be capable of
`glowing for prolonged periods when the light source is
`removed. Furthermore, the glow is more readily seen
`by a user descending as well as ascending the staircase 65
`than where the photoluminescent material is located on
`the face of the riser as hitherto considered necessary.
`Also, it has been found that any obstruction on the
`
`2
`staircase is more readily apparent to the user than when
`the photoluminescent material is mounted on the riser
`of the staircase. It has also been found that although the
`material is mounted upon that part of the stair exposed
`to severe abrasion and wear, the action of the users'
`shoes and feet is generally parallel to the exposed face
`so that they act to wipe the exposed face and thus re(cid:173)
`duce problems to the build-up and embedding of dirt in
`the exposed face. The presence of the protective leading
`edge not only reduces the risk of detachment of the
`photoluminescent material from the stair tread, but also
`serves to support part of the load of a users' shoes or
`feet and thus to reduce wear of the exposed face.
`
`SUMMARY OF THE INVENTION:
`Accordingly, the present invention provides a gener(cid:173)
`ally planar member adapted to be mounted upon or
`adjacent the leading edge of the tread of a step of a
`staircase and extending rearwardly over part or all of
`the width of the step, which rearwardly extending por(cid:173)
`tion of the member is provided with a strip of photolu(cid:173)
`minescent material.
`In a preferred embodiment, the invention provides a
`device for affixing to the horizontal portion (the tread)
`of a step of a staircase (the tread) which device com(cid:173)
`prises a generally planar horizontal elongated member
`adapted to be mounted adjacent the leading edge of the
`step and to extend rearwardly across at least part of the
`area of the tread of the step and having a wear-resistant
`exposed translucent upper face and incorporating a
`photoluminescent material, the leading edge of the
`member being provided with a protective member.
`Preferably, the device comprises an elongated metal
`or other extrusion or moulding having an axial recess
`therein into which the photoluminescent material is
`incorporated, the photoluminescent material having a
`translucent abrasion resistant overlay providing the
`exposed upper face, the member having an upstanding
`leading edge along the recess which provides the pro(cid:173)
`tective member for the photoluminescent material. It is
`also preferred that at least initially the exposed face be
`proud of the upper surface of the protective member
`along its leading edge.
`In a particularly preferred form of the device, the
`photoluminescent material is incoporated into a lami(cid:173)
`nated plastic material, notably a flooring grade sheet
`plastic material, and a strip of that material is provided
`in the recess of the moulding or extrusion.
`Flooring grade plastic sheet material containing a
`photoluminescent material is believed novel, and the
`invention therefore also provides a plastic material suit(cid:173)
`able for mounting upon an area to be walked upon by a
`user and in strip, sheet or other planar form, which
`material comprises a base layer having a reflective
`upper surface; an intermediate layer incorporating a
`photoluminescent material; and an upper translucent
`wear-resistant layer. Preferably, the base layer incorpo(cid:173)
`rates a white pigment; the intermediate layer incorpo(cid:173)
`rates a combination of a photoluminescent material and
`light reflective particles such as glass beads or chips;
`and the upper layer is translucent and is provided with
`a wear resistant upper surface. A particularly preferred
`upper layer comprises a vinylic polymer having a plasti(cid:173)
`ciser content of from 25 to 45 parts by weight per 100
`parts by weight of resin and the composite sheet has a
`Shore A hardness of from 80 to 95.
`The invention further provides a step of a staircase
`having mounted adjacent the leading edge of the tread
`
`Page 4 of 7
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`4,998,391
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`3
`thereof and extending r~arwardly thereof over at least
`part of the area of the tread a device of the invention.
`The invention may be applied to a wide range of
`forms of staircase: for example to wooden, steel or con(cid:173)
`crete straight or curved fixed staircases in a building, to 5
`companionways in ships; and to portable structures
`such as ladders, loft ladders and step ladders. For con(cid:173)
`venience the term staircase is used herein to denote in
`general all such structures comprising a flat surface (the
`tread) upon which a user steps, which surfaces are ar- 10
`ranged in ascending or descending sequence to enable
`the user to ascend or descend between different levels.
`The. invention is of especial use on fixed staircases
`mounted in buildings which have a series of horizon(cid:173)
`tally staggered treads linked to one another by upright 15
`risers located adjacent the front edge of an upper tread
`and adjacent the rear edge of a lower tread to form a
`conventional staircase. However, it will be appreciated
`that the risers may be omitted to give what is known as
`an open tread staircase.
`
`20
`
`4
`strips of photoluminescent material, with one or more
`further devices (lOa, 10b) affixed upon the rearward
`area of the tread as.shown in FIG. 2.
`The extrusion 11 is a generally planar member affixed
`upon the upper surface of the tread. However, as shown
`in FIG. 1, it is preferred that the extrusion 11 have a
`dependent front skirt 12 which overlies the upper por(cid:173)
`tion of the riser 2 of the step, or an upstanding rear edge
`which extends up at least part of the riser at the rear of
`the tread. The precise form and size of the extrusion 11
`can be selected in known manner to suit the size and
`shape of the step it is to fit.
`The extrusion 11 is provided with one or more
`grooves or recesses 13, preferably longitudinal, into
`which strips 14 of photoluminescent material are to be
`secured. The recesses 13 can be formed as the extrusion
`11 is formed or can be formed subsequently, for exam(cid:173)
`ple by clamping strip retaining bars 30 onto a base plate
`31 to clamp the edges of the strips 14 in place, as shown
`in FIG. 4. The recesses 13 desirably take the form of
`rectangular cross-section channels in the upper face of
`the extrusion into which strips 14 of the photolumines(cid:173)
`cent material are a close fit. If desired the channels can
`have undercut edges to co-operate with a trapezoidal
`cross-section to strips 14. The channels extend axially of
`extrusion 11, preferably as unbroken recesses alo,ng the
`whole length of the extrusion so that the photolumines(cid:173)
`cent material lies across substantially the whole width
`of the stair tread as shown in FIG. 2. As shown in FIG.
`30 2, there can be two or more strips of photoluminescent
`material along each extrusion 11.
`As indicated above, the strips 14 ofphotoluminescent
`material are to be located inwardly of the leading edge
`of the extrusion so that the leading edge of the extrusion
`35 prtects the edge of strip 14 against the wear of users
`shoes and feet. We also prefer that the extrusion be
`mounted at or adjacent the nose of the step to give a
`user an indication of the position of the edge of the step.
`Thus, we prefer that the leading edge of extrusion 11 be
`located within 30 mms, preferably within 0 to 20 mms,
`of the edge of tread 1. Otherwise, the extrusion 11 and
`strip 14 can be located as desired. Where extrusion 11
`has a dependent front skirt 12, it will be appreciated that
`this carries the leading edge of the extrusion over the
`leading edge of the step and this skirt or the upstand at
`the rear of the extrusion can carry one or more photolu-
`minescent strips to indicate the position of the riser to
`the step to a user.
`Within recess 13 is located a strip of photolumines(cid:173)
`cent material 14. Preferably, this strip is provided by a
`length of substantially non-porous plastic material in(cid:173)
`corporating a photoluminescent material, which strip is
`a close fit within recess 13. The strip 14 can be secured
`within the recess by any suitable method, for example
`by being a tight fit within an undercut lip to the recess
`as shown in FIG. 2 or by screws or other fixing means.
`It is particularly preferred to secure the strip in place by
`a suitable adhesive. Alternatively, the base of the recess
`can be coated with a suitable photoluminescent paint or
`the like.
`The photoluminescent material strip is protected
`against excessive abrasion and lifting by the extrusion
`11. If desired, the recess 13 can be given a transparent
`cover 15 to protect the strip 14 and to secure it within
`the recess as shown in FIG. 5. However, it is preferred
`to form the strip 14 from a flooring grade plastic mate-
`rial incorporating a translucent non-porous upper layer
`so that the exposed upper face of strip 14 will resist
`
`DESCRIPTION OF THE DRAWINGS:
`For convenience the invention will be described in
`terms of a fixed conventional staircase with treads and
`risers and to aid understanding of the invention it will be 25
`described with respect to the preferred form thereof
`shown in the accompanying drawings in which
`FIG. 1 is a vertical section through a step of a stair(cid:173)
`case carrying a member of the invention,
`FIG. 2 is a plan view of the step of FIG. 1;
`FIG. 3 is a vertical section through a flooring grade
`plastic material for use in the member of FIG. 1; and
`FIGS. 4 and 5 are views of alternative forms of the
`member of FIG. 1.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`The staircase is formed from a staggered series of
`substantially horizontal treads I linked by substantially
`vertical risers 2. Typically the step will be constructed 40
`from wood as shown. However, other materials of con(cid:173)
`struction may be used and the tread and riser need not
`be separate members, but can be formed as a single unit
`as when the staircase is cast in concrete or is made from
`welded steel or the like. As indicated above, the risers 2 45
`may be omitted and the treads can be of slatted or mesh
`construction. However, it is preferred that the tread
`present a solid horizontal surface upon which the user
`treads.
`Upon some or every step tread is mounted a device 10 50
`of the invention incorporating a photoluminescent
`member. This can take the form of a simple strip of
`flooring grade plastic material incorporating the photo(cid:173)
`luminescent material and secured to the tread 1 in the
`desired position by adhesive, screws or the like. How- 55
`ever, it is preferred to support the strip of material in a
`metal or other edge piece which not only protects the
`nose of the stair against wear, but also secures and pro(cid:173)
`tects the leading edge of the photoluminescent material.
`Such an edge piece typically comprises a steel, alumin- 60
`ium or rigid plastic extrusion 11 having one or more
`axial recesses, slots or grooves 13 into which the photo(cid:173)
`luminescent material 14 is located.
`The extrusion 11 preferably extends over substan(cid:173)
`tially all its length rearwardly at least part of the way 65
`over the face of the tread 1 as shown in FIG. 2. If de(cid:173)
`sired, the tread can be provided with one device of the
`invention along its nose, which can carry two or more
`
`Page 5 of 7
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`4,998,391
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`wear by the feet of use~. Where this is done, the upper .
`face of strip 14 can be set so that it is flush with or stands
`slightly proud of the upper face of the extrusion 11 as
`shown in FIG. 1. By doing this, problems of loss of
`illumination from the photoluminescent strip due to dirt 5
`intrapment within the recess or on the face of strip 14
`are reduced. In effect, the face of the strip 14 will be
`wiped by the users' feet as they tread on the step, thus
`preventing excessive build up of dirt on the face of the
`strip. Furthermore, where the surface of strip 14 is worn 10
`down to the level of the leading edge of extrusion 11,
`the extrusion will carry at least part of the weight of a
`user and will protect the strip 14 against rapid erosion
`during normal use of the staircase.
`Alternatively, the material of one or more layers of 15
`the strip can be selected so as to allow the strip to be
`compressed slightly so that the majority of the load of
`the user is supported by the extrusion 11 and not by the
`strip 14. Thus, the lower layer of a laminated plastic
`strip 14 can be a foamed material.
`The strip 14 can be formed from conventional ingre(cid:173)
`dients using conventional plastics technology, except
`that the polymer composition forming all or part of the
`strip contains one or more photoluminescent active
`materials. Thus, the strip 14 can be formed by extruding 25
`a suitable thermoplastic polymer composition such as a
`translucent polyvinylic resin or the like and applying a
`coat of a photoluminescent paint or the like to the under
`surface thereof. However, it is particularly preferred
`that the strip 14 be in the form of a composite material 30
`having a flexible protective upper layer and a lower
`photoluminescent layer. Thus, the strip can be formed
`by co-extruding a clear PVC layer having a Shore A
`hardness of from 85 to 92 with a PVC layer containing
`photoluminescent material. Suitable PVC resins for 35
`present use are those containing from 30 to 40 parts by
`weights of plasticizer, e.g. a phthalate plasticizer, per
`100 parts by weight of resin. It is especially preferred
`that there should also be a lower reflective layer to
`enhance the light emission from the strip.
`A suitable structure for the strip 14 is shown in FIG.
`3 and comprises a base layer 20, a layer 21 containing
`the photoluminescent material and a translucent top
`layer 22. Such a material can be made from conven(cid:173)
`tional flooring grade plastics materials and using con- 45
`ventional sheet plastics fabrication techniques. Thus,
`the base layer 20 can be a sheet of vinylic, polyurethane
`or polyethylene polymer or a blend or copolymer of
`such materials, for example with butadiene and/or sty(cid:173)
`rene. The layer 20 can be a rigid polymer layer having 50
`a Shore hardness of substantially 100; or can be formed
`from an expanded polymer to allow the resultant strip
`14 to have a measure of compressability. Typically,
`layer 20 will be from 1 to 5 ms thick and can be made up
`from a series of thinner layers if required.
`As indicated above, layer 20 is to be reflective so that
`the maximum light from the intermediate layer 21 is
`directed upwardly. This can be achieved by forming a
`reflective layer 24 on the face of layer 20, e.g. by laying
`a metal foil upon layer 20 or by deposition a metallic 60
`film on layer 20. Alternatively, layer 20 need not be a
`polymer layer but could be in the form of a reflective
`metal foil or even the highly polished base to the recess
`13. However, it is preferred to incorporate a white
`pigment such as titanium oxide pigment and/or reflec- 65
`tive particles such as glass beads or chips into the poly(cid:173)
`mer from which layer 20 is formed so that the layer is
`inherently reflective.
`
`6
`Layer 21 contains the photoluminescent material,
`preferably in conjunction with reflective particles such
`as glass beads or chips which enhance light emission
`from the layer. The photoluminescent material can be
`selected from a wide range of such materials. Thus,
`suitable materials for present use include radioactive
`gasses, e.g. tritium, encapsulated in a polymer bead such
`as a polycarbonate; or metal sulphides, notably calcium,
`stronium or zinc sulphides or mixtures thereof. If de(cid:173)
`sired, the active ingredient can be applied as a coating to
`a solid carrier, such as a finely particulate metal, e.g.
`copper. Typically, the photoluminescent material will
`be present as a particulate or crystalline material dis(cid:173)
`persed in a thermoplastic polymer base. The amount of
`photoluminescent material is typically from 50 to 500
`gs, preferably 100 to 400 gs, of active ingredient per
`square metre of exposed surface area through which
`light is to be emitted. If desired, the layer 21 can contain
`other ingredients, notably materials which fluoresce in
`daylight such as organic fluorescins. Suitable polymer
`sheets containing the photoluminescent materials are
`available commercially and may be used as such in the
`prduction of the strips 14. However, the layer 21 may
`also be formed in situ by applying a paste or solution of
`the required ingredients and a carrier polymer, or an
`oligomer or monomer precursor thereof, to layer 20 or
`to the base of recess 13 as indicated above, and causing
`the polymer for the layer 21 to be formed in situ by
`suitable polymerisation techniques as is known in the
`art.
`The strip 14 has an upper layer 22 which is to be
`exposed to the feet of the user. This layer is translucent
`not only to allow the photoluminescent material to be
`activated by light falling on strip 14 but also to allow the
`glow from layer 21 to be visible in the dark. Preferably,
`layer 22 is transparent and substantially clear. Thus,
`layer 22 can be formed from a polyvinyl, polyurethane
`or other polymer using conventional techniques and
`additives to enhance the UV stability and other func(cid:173)
`tions of the polymer layer. The layer 22 protects layer
`21 against abrasion during use and therefore is formu(cid:173)
`lated to floor grade requirements as is known in the art.
`Thus, the layer will typically be formed· from a clear
`PVC resin having a Shore A hardness of from 80 to 97
`to give it the desired flexibility for wear resistance.
`The overall composite structure for strip 14 can be
`made by co-extrusion where only two layers are present
`or by laminating pre-formed polymer sheets using hot
`pressing or other conventional techniques to cause the
`layers to adhere to one another, optionally with adhe(cid:173)
`sive interface layers. Thus, a PVC composite structure
`can be made by causing the various layers to fuse to(cid:173)
`gether under pressure and at elevated temperatures. In
`a particularly preferred method of manufacture, a clear
`PVC top layer having a shore hardness of 86 to 92, an
`intermediate layer containing photoluminescent zinc
`sulphide particles and a base layer of one or more plies
`of a rigid PVC having a Shore hardness of substantially
`100 is fused together at 150° to 175° C. under a pressure
`of from 100 to 200 psi gauge.
`The composite structure described above may omit
`one or more of the layers, e.g. the base reflective layer
`where a reflective foil is present or the base of the recess
`13 is sufficiently highly polished to provide the neces(cid:173)
`sary reflective effect.
`The composite structure described above may con(cid:173)
`tain other ingredients conventionally used in polymer
`mixes, for example antioxidants or dyes in the upper
`
`Page 6 of 7
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`4,998,391
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`layer to provide. a colo~r other than green to the light
`emitted from the strip 14; and may be subjected to fur(cid:173)
`ther treatment as is known to enhance its properties.
`Thus, the composite structure can be given a surface
`coating of a silicone or other polmer to provide a non- 5
`slip surface thereto and/or to aid resistance to adher(cid:173)
`ence of dirt to the exposed face of layer 22. The strips 14
`are formed from the composite structure by cutting the
`overall sheet of material into the required strips using a
`mechanical knife or air blade or a heated wire cutter.
`The strips 14 are secured into the recesses 13 using
`any suitable technique and will usually extend for the
`full length of the recess. However, it is within the scope
`of the present invention for the strips 14 to be compara(cid:173)
`tively short and to alternate with, for example, conven- 15
`tional anti-slip material also carried in recesses 13.
`In use, the extrusion 11 is secured by any suitable
`means to the desired location on the treads 1 of a stair(cid:173)
`case. However, it will be appreciated that the composite
`flooring grade structure described above, can also be 20
`used elsewhere where a photoluminescent material is
`required in a location where it is to be subjected to
`abrasion. Thus, the composite structure can be formed
`into broad strips which are set into extrusions or similar
`settings to provide markers for mounting on or into the 25
`floor of a room. In the event of a power failure or other
`emergency when the light source fails, such markers
`can provide a path on the floor which occupants of the
`room can follow.
`Thus, the invention also provides a method for mark- 30
`ing areas to be trodden by a user or lines of travel to be
`followed by a user, notably foot paths on the floor of a
`structure, which comprises securing a device or a wear(cid:173)
`resistant flooring grade composite structure of the in(cid:173)
`vention to that area or adjacent that line of travel.
`I claim:
`1. A device comprising a generally planar member
`adapted to be mounted upon or adjacent the leading
`edge of the horizontal tread portion of a step of a stair(cid:173)
`case and extending rearwardly over part or all of the 40
`width of the step, which rearwardly-extending portion
`
`8
`of the member is provided with at least one recess ex(cid:173)
`tending widthwise of the member and accommodating
`at least one light-emitting element, wherein the or each
`element comprises a strip of a flooring grade plastic
`sheet material which comprises a base layer having a
`reflective upper surface, an intermediate layer incorpo-
`rating photoluminescent material and an upper translu(cid:173)
`cent, wear-resistant layer, said upper layer of the or
`each element having an exposed upper face disposed
`10 above the remainder of the device.
`2. A device as claimed in claim l, wherein the base
`layer incorporates a white pigment and wherein the
`intermediate layer incorporates a combination of a pho(cid:173)
`toluminescent material ·and light-reflective particles,
`notably glass beads or chips.
`3. A device as claimed in claim 1, wherein the upper
`layer comprises a vinylic polymer having a plasticiser
`content of from 25 to 45 parts by weight per 100 parts
`by weight of resin and the composite sheet has a Shore
`A hardness of from 80 to 95.
`4. A device as claimed in claim 1, wherein the leading
`or trailing edge of the device carries a dependent skirt
`or an upstanding edge adapted to cooperate with the
`riser adjacent the tread of the step on which the device
`is mounted.
`5. A device for use on a tread portion of a step, said
`device consisting of an elongated member which de(cid:173)
`fines an upper surface and includes at least one elon(cid:173)
`gated recess, and a light-emitting element fixedly posi(cid:173)
`tioned in each elongated recess, said member being
`mountable on a tread portion of a step so that each
`light-emitting element extends in a length dimension of
`the tread portion, each light-emitting element compris-
`35 ing a base layer having a reflective upper surface, an
`intermediate layer incorporating a photoluminescent
`material, and an upper translucent, wear-resistant layer,
`said upper layer having a wear-resistant, exposed upper
`face which is located above said upper surface of said
`member.
`• • • • •
`
`45
`
`50
`
`55
`
`60
`
`65
`
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