AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Applicant(s): Austact Pty Ltd Invention Title: A TACTILE MARKER The invention is described in the following statement: -2 A TACTILE MARKER FIELD OF THE INVENTION 5 The present invention relates to a tactile marker. BACKGROUND OF THE INVENTION 10 Tactile markers may be positioned on walkway surfaces so as to assist pedestrians in identifying transitions, for example at pedestrian lights, at the foot or head of an escalator or stairway, and along the edge of a railway platform. 15 Tactile markers are commonly formed from metal or plastics materials. A tactile surface of such markers, being a surface that pedestrians interact with for example by walking on, will therefore often have a relatively smooth 20 surface. It is however desirable to provide a tactile surface that is not overly smooth so as to reduce the occurrence of pedestrian slippage as they walk on the tactile marker. Some tactile markers are formed from metal and a non-slip sticker is then applied to the tactile 25 surface. Applying the sticker is labour intensive and relatively expensive and the bonding of the sticker to the marker is often unsatisfactory. As such there is a need for improvement in this field of 30 technology. 1751670_1 (GHMatters) -3 SUMMARY OF THE INVENTION In accordance with a first aspect of the present invention there is provided a tactile marker comprising a head 5 portion arranged to sit on a walkway surface and a depending stem arranged to be located as a press fit within a hole in the walkway, the head portion having a tactile surface, the stem and head portions comprising a first material that has a recess at the tactile surface, io the head portion further comprising a second material disposed in the recess and the second material comprising a frictional component forming at least a portion of the tactile surface. 15 In one embodiment, the stem and head portions comprising the first material are formed by injection moulding. Embodiments of the present invention have a significant advantage as the tactile marker typically is convenient to 20 manufacture and provides a tactile surface that may reduce slippage. Further, the recess allows a stronger bond to be formed between the frictional component and the head portion and makes the frictional component less prone to being removed from wear. 25 In one embodiment, the second material comprises a bonding component that couples the frictional component to the head portion. The bonding component of the second material may be disposed such that the bonding component is between 30 the frictional component and the head portion. Alternatively, the frictional component may be dispersed. within.the bonding component wherein and a portion of the 1751870_1 (GHMatters) -4 frictional component is exposed at the tactile surface. In a further embodiment, the frictional component covers the entire tactile surface. 5 In another embodiment, the second material is the frictional component. The first material may comprise a polymeric material such as a thermosetting polymeric material that is suitable for io injection moulding. In one specific embodiment the first material comprises polyurethane, but may in this embodiment alternatively also comprise another polymeric material that is.suitable for injection moulding. 15 Especially in embodiments in which the bonding component couples the frictional component to the head portion, the bonding component may comprise an adhesive. The adhesive may be any suitable polymeric material such as polyurethane. In specific examples, the adhesive may be a 20 two-part polyurethane adhesive. The frictional component may comprise a granular material. The size of the granular material may be any appropriate size. For example, the granular material may have a grain 25 size in the range of lmm to 0.01mm, 0.5mm to 0.025mm or 0.1mm to 0.05mm. In specific embodiments, the frictional component comprises silicon carbide, but may alternatively comprise any other suitable component. 30 In one specific embodiment the second material comprises the bonding component and the frictional component comprises a granular material having grains and at least a portion of the grains are exposed at the tactile surface. 1751670_1 (GHMaters) -5 The recess may comprise at least one recession and/or projection. The at least one recession and/or projection may have a substantially dovetailed cross sectional shape. 5 The at least one recession typically provides the significant advantage of providing a stronger bond between the second material and the head portion. Consequently, the frictional component is more firmly held at the tactile surface. 10 It will be appreciated that alternatively the stem and the head portion comprising the first material may be formed from other materials, such as a metallic material. 15 In accordance with a second aspect of the present invention there is provided a method of manufacturing a tactile marker comprising: forming a head portion and a depending stem, the head portion being arranged to sit on a walkway surface, the 20 depending stem being arranged to be located as a press fit within a hole in the walkway, the head portion having a tactile surface, the stem and head portions comprising a first material having a recess in the head portion at the tactile surface; and 25 disposing a second material into the recess, the second material comprising a frictional component forming at least a portion of the tactile surface. In one embodiment the stem and the head portion comprising 30 the first material are injection moulded. In one embodiment, disposing the second material in the recess comprises coupling the frictional component to the 1751870-1 (GHMatters) -6 head portion via a bonding component of the second material. Coupling the frictional component to the head portion may comprise disposing the bonding component such that the bonding component is between the frictional s material and the head portion. Alternatively, coupling the frictional component to the head portion may comprise dispersing the frictional material within the bonding component wherein at least a portion of the frictional material is exposed at the tactile surface. 10 The first material may comprise a polymeric material such as a thermosetting polymeric material that is suitable for injection moulding. In specific embodiments, the first material comprises polyurethane, but may alternatively is comprise any other polymeric material that is suitable for injection moulding. Coupling the frictional component to the head portion may comprise adhering the frictional component to the head 20 portion via the bonding component. The bonding component may be an adhesive. The adhesive may be any suitable polymeric material such as polyurethane. In specific examples, the adhesive may be a two-part polyurethane adhesive. 25 Adhering the frictional component to the head portion via the bonding component may comprise disposing the bonding component in the recess in a liquid form and disposing the frictional component onto the bonding component prior to 30 the bonding component hardening. The frictional component may comprise a granular material. The granular material may have any appropriate grain size 1751670_1 (GHMatters) -7 so as to achieve a frictional resistance of the tactile surface. For example, the granular material may have a grain size in the range of 1mm to 0.01mm, 0.5mm to 0.025mm or 0.1mm to 0.05mm. In specific embodiments, the s frictional component comprises any one of silicon carbide, but may alternatively comprise any other suitable component. Moulding the head portion may comprise forming at least io one recession and/or projection in the recess. The at least one recession and/or projection in the recess may be formed so as to have a substantially dovetailed cross sectional shape. is It will be appreciated that alternatively the stem and the head portion comprising the first material may be formed from other materials, such as a metallic material. The invention will be more fully understood from the 20 following description of specific embodiments of the invention. The description is provided with reference to the accompanying drawings. Brief Description of the Drawings 25 Figure.1 shows a perspective view of a tactile marker in accordance with an embodiment of the present invention and showing a recess of a head portion; 30 Figure 2 shows a partial perspective view of the marker of Figure 1 with the tactile marker having been rotated through approximately 450; 17516701 (GHMatters) -8 Figure 3 shows a front elevation view of a head portion of a tactile marker in accordance with a further embodiment of the present invention and showing a recess of the head portion in phantom; 5 Figure 4 shows a perspective view of the tactile marker of Figure 1 having a second material disposed in the recess; Figure 5 shows a perspective view of the tactile marker of 10 Figure 1 having a second material comprising a frictional component disposed in the recess; and Figure 6 shows a flow chart outlining a method of forming the tactile marker of Figure 5. 15 Detailed Description of Specific Embodiments Embodiments of the present invention generally relate to a tactile marker comprising a head portion and a depending 20 stem, the head portion having a tactile surface, the stem and head portions comprising a first material which has a recess at a tactile surface, the head portion further comprising a second material disposed in the recess and the second material comprising a frictional component 25 forming at least a portion of the tactile surface; and a method of manufacturing the same. Referring initially to Figures 1 and 2 there is shown a tactile marker 10 comprising a generally frusto-conical 30 head portion 12 having a beveled surround 14 that extends to a marginal rim 16 and an integrally moulded stem 18 projecting downwardly from an underside of the head portion 12. The head portion 12 comprises a recess 20. In 1751670_1 (GHMatters) -9 one embodiment, the head portion 12 and the stem 18 are formed from a suitable thermosetting polymeric material such as polyurethane. It will be appreciated however that the head portion 12 and the stem 18 may be formed from any 5 appropriate material. In use, the head portion 12 is arranged to sit on a walkway surface such that the underside of the head portion 12 is substantially flush with the walkway surface and with the depending stem 18 located as a press fit within a hole in the walkway. 10 In this embodiment the stem 18 is formed along its length with five axially spaced barbs 22, 24, 26, 28 and 30, the lowermost one of which comprises a generally conical end portion of the stem 18. Further, the stem 18 is formed 15 between the uppermost barb 22 and the underside of the head portion 12 with four longitudinally extending splines 32 (three of which are shown in Figure 1). Each of the barbs 22, 24, 26, 28 and 30 comprises a 20 generally annular land 34 having an outer periphery margin 36 and, formed integrally with the land 34, a generally conical portion 38. The conical portion 38 associated with each of the lands 34 is, as shown, located below the land 34 and has a major diameter that is the same as (or 25 approximately equal to) that of the land 34, and the conical portion 38 has a cross-section that reduces in diameter in a direction away from the head portion 12. Figure 3 shows a cross sectional view of the head portion 30 12 revealing the recess 20 having a plurality of dovetail shaped recessions 42. The recessions 42 may have any appropriate shape and orientation and typically are shaped 1751670_1 (GHMatters) - 10 to facilitate bonding a material, such as a polymeric material to the head portion 12. In this example, an adhesive is shown disposed in the s recess 20 in Figure 4. The adhesive 44 has been applied in the recess 20 such that the adhesive 44 has flowed into recessions 42. The adhesive in this example has been applied as a liquid which will subsequently harden. When set the shape of the recessions 42 and the shape of the 10 adhesive 44 provide a relatively strong bond. In this example the adhesive is a two-part polyurethane adhesive. However it will be appreciated that the adhesive may be any suitable adhesive. is Figure 5 shows a frictional component 46 having been applied to the adhesive 44 so as to form at least a part of a tactile surface 48. The frictional component 46 may comprise a granular material. The granular material may have any appropriate grain size so as to achieve a 20 frictional resistance of the tactile surface. For example, the granular material may have a grain size in the range of 1mm to 0.01mm, 0.5mm to 0.025mm or 0.1mm to 0.05mm. In this example, the frictional component 46 comprises 25 silicon carbide having a grain size in the range of 0.5mm to 0.025mm. However it will be appreciated that any appropriate granular frictional material may be used that is sufficiently hard. Grains of the frictional component 46 are exposed at the tactile surface 48. In one 30 embodiment the adhesive 44 is disposed between the frictional component 46 and the head portion 12 such that the adhesive 44 is substantially covered by the frictional component 46. Alternatively, the frictional component 46 1751670_i (GHMalter) - 11 may be arranged at the tactile surface 48 such that a substantial amount of the adhesive 44 is present at the tactile surface 48. In a further alternative, the frictional component 46 is dispersed in the adhesive 44 5 wherein at least a portion of the frictional component is exposed at the tactile surface 48. In light of the above, the tactile marker 10 is therefore convenient to manufacture and provides a tactile surface 10 for substantially reducing slippage when the marker is in use walked on by pedestrians. The dimensions of the various parts of the tactile marker 10 will be determined by particular application to which is the marker might be put. However, in one embodiment of the marker the barbs 22, 24, 26, 28 and 30 may have an outside diameter of 9.5 mm and the depending stem 18 will in use be pressed or otherwise forced into a drilled hole having a diameter within the range 8.0 to 8.5 mm. With such an 20 interference fit, when, in use, the depending stem 18 is pressed into the hole, a peripheral portion of the land 34 of each of the barbs 22, 24, 26, 28 and 30 will be deflected upwardly and inwardly, to cause a tensile stress to be induced in the conical portion 38 and a radially 25 inward reactive force to be exerted on the peripheral margin 36 of the barb by the surrounding wall of the hole. Thus the stem 18 will be held captive against longitudinal displacement from the hole by the barbed 22, 24, 26, 28 and 30 will be held captive against rotation within the 30 hole by the splines 32. The splined region of the stem has the same effective diameter as the barbs 22, 24, 26, 28 and 30 and, thus, also engages with an interference fit in the hole. 1751670_1 (GHMatters)- - 12 Further, in order to enhance retention of the stem 18 in the hole, an adhesive may in some circumstances be inserted into the hole before the stem is inserted. Then, in order that the adhesive, when used, might flow along 5 the full length of the stem and provide for maximum anchorage, the land 34 of each of the barbs 22, 24, 26, 28 and 30 is formed with two diametrically disposed flat chordal regions 40, and the chordal regions 40 are displaced by substantially 900 on successive adjacent barbs 10 22, 24, 26, 28 and 30. Referring now to Figure 6 there is shown a method 50 of manufacturing a tactile marker comprising the step of moulding 52 a head portion and a depending stem, the head 15 portion being arranged to sit on a walkway surface the depending stem being arranged to be located as a press fit within a hole in the walkway, the head portion having a tactile surface, the stem and head portions comprising a first material wherein moulding the first material forms a 20 recess in the head portion at the tactile surface and the step of disposing 54 a second material into the recess, the second material comprising a frictional component forming at least a portion of the tactile surface. 25 The step. of moulding the head portion and depending stem from the first material may comprise the use of injection moulding or similar techniques. In this way the head portion and the stem will be formed integrally from the same material, such as polyurethane, which can assist in 30 convenient manufacturing. 1751670_1 (GHMaters) - 13 The step of disposing 54 the second material in the recess may further comprise coupling the frictional component to the head portion using a bonding component. 5 The step of disposing 54 may be done as part of a production line so as to further assist in the convenient manufacture of a tactile marker in accordance with the present embodiments. 10 Coupling the frictional component to the head portion may comprise disposing the bonding component such that the bonding component is between the frictional material and the head portion. In an alternative embodiment, coupling the frictional component to the head portion may comprise is dispersing the frictional material within the bonding component such that at least a portion of the frictional material is exposed at the tactile surface. When the bonding component is an adhesive, coupling the 20 frictional component to the head portion comprises adhering the frictional component to the head portion. Adhering the frictional component to the head portion using the bonding component may comprise disposing -the 25 bonding component in the recess in a liquid form and disposing the frictional component onto the bonding component prior to the bonding component.hardening. In one embodiment, forming the head portion comprises 30 forming at least one recession and/or projection in the recess wherein the at least one recession and/or projection in the recess is formed so as to have a substantially dovetailed cross sectional shape. This 1751670_1 (GHMatters) - 14 assists in forming a stronger bond between the adhesive and the head portion and therefore assists in retaining the frictional component at the tactile surface. 5 Although the invention has been described with reference to particular examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. For example, in the embodiment described in the Figures, the recess has a circular shape when 10 viewed from the top. However, the recess may have any desired shape such as an annular shape. Further, although the stem and head portion are described as being formed by injection moulding, it will be appreciated that the stem and head portion may be formed from a metallic material, 15 or any other suitable material. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary 20 implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 17518701 (GHMatters)