AU2008202373B2

AU2008202373B2 - Tactile ground surface indicator

Info

Publication number: AU2008202373B2
Application number: AU2008202373A
Authority: AU
Inventors: Daniel Dedomenico
Original assignee: CTA Australia Pty Ltd
Current assignee: CTA Australia Pty Ltd
Priority date: 2007-07-05
Filing date: 2008-05-29
Publication date: 2009-08-06
Anticipated expiration: 2028-05-29
Also published as: AU2009233692B2; AU2009233692A1; NZ572592A; AU2010201685B2; NZ568738A; AU2008202373A1; AU2008202373C1; AU2010201685A1

Description

Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT (ORIGINAL) Name of Applicant: CTA Australia Pty Ltd Actual Inventor: Daniel DeDomenico Address for Service: DAVIES COLLISON CAVE, Patent Attorneys, I Nicholson, Melbourne, Victoria 3000. Invention Title: "Tactile ground surface indicator" Details of Associated Provisional Applications No: 2007903648 filed 5 July 2007; and No. 2007906297 filed 16 November 2007. The following statement is a full description of this invention, including the best method of performing it known to us: Q:\OPER\MRF\2008\NZ 30547474 150 doc - 29/5/08 Tactile Ground Surface Indicator The present invention relates to tactile indicators which are disposed on a ground surface to provide a tactile and/or visual indication to a person, particularly a blind or vision 5 impaired person, walking on the surface. Tactile ground surface indicators are specially configured protrusions which are positioned on walking surfaces. Such indicators are typically found in public areas in and around buildings and stairs, or at pedestrian crossings and the like, to forewarn pedestrians, 10 particularly blind or vision-impaired persons, of an upcoming obstruction or hazard. When the person feels the tactile indicators under their feet, they are made aware that their next step should be taken with caution. Tactile ground surface indicators can be located, for example, in approaches to steps or 15 stairs, edges of railway platforms, traffic crossings, ramps and so forth. It is advantageous to machine or mould tactile indicators from strong, durable material, such as stainless steel. Stainless steel indicators are typically adhered to the ground with adhesive such as epoxy adhesive, either directly on the ground surface or in a recess or 20 cavity in the ground into which a stem of the indicator is received. The need for adhesive complicates the installation of the tactile indicators, in that supplies of such adhesive must be maintained and the indicators are vulnerable to dislodgement before the adhesive has set, generally necessitating downtime, usually of the order of 24 hours, during which the area in which the indicators have been installed must be cordoned off. 25 According to a first aspect of the present invention, there is provided a tactile ground surface indicator, comprising a rigid indicator portion arranged to lie over a ground surface, and a rigid projecting portion extending from the indicator portion to be receivable in a cavity formed in the ground, the indicator further comprising a casing applied to the 30 projecting portion prior to receipt thereof in the cavity, the casing being deformable against a wall of the cavity upon insertion of the projecting portion into the cavity to retain the indicator. Deformation of the casing against the wall establishes sufficiently tight contact -2 engagement between the casing and the wall to resist upward pulling forces on the indicator. Such engagement will generally include frictional engagement. Advantageously, the tactile ground surface indicator can thus be installed very rapidly, 5 without any adhesive, whilst still being robust and durable. The indicator, and in particular the casing, may be driven into the cavity to cause deformation of the casing. 10 The casing may be overmoulded to, or moulded over, the projecting portion. In a preferred embodiment of the present invention, the projecting portion comprises a stem which extends downwardly from the indicator portion to be receivable in the cavity, and the casing is fixed to the stem. The casing may be overmoulded to, or moulded over, 15 the stem. In a preferred embodiment of the present invention, the casing is plastically deformable against the cavity wall. 20 Preferably, the casing is formed with at least one protuberance which protrudes radially outwardly to deform against the cavity wall. In one embodiment of the present invention, the at least one protuberance comprises a pair of opposed ribs which extend in general alignment with the direction of insertion of the 25 casing in the cavity to engage opposed portions of the cavity wall. In an alternative preferred embodiment of the present invention, the at least one protuberance extends circumferentially around the casing to engage the opposed portions. In particular, the at least one protuberance may comprise one or more ribs extending 30 around the casing. The ribs may define a barbed or saw-tooth configuration which facilitates insertion of the casing. Consistent with national standard no. AS/NZS 1428, tactile ground surface indicators according to preferred embodiments of the present invention provide areas of raised -3 ground surface texture treatment, designed to provide blind or vision-impaired pedestrians with warning and/or directional orientation information. According to a second aspect of the present invention, there is provided a method of 5 forming a tactile ground surface indicator, the method comprising: providing a rigid body comprising an indicator portion arranged to lie over a ground surface and a projecting portion extending from the indicator portion to be receivable in a cavity formed in the ground; and prior to receipt of the projecting portion in the cavity, applying a casing to the 10 projecting portion, the casing being deformable against a wall of the cavity upon insertion of the projecting portion into the cavity to retain the indicator. Preferably, the projecting portion comprises a stem and the casing is moulded over the stem. 15 Preferably, the casing is moulded over the projecting portion. In a preferred embodiment of the invention the casing is overmoulded to the projecting portion. 20 The present invention will now be described, by way of non-limiting example only, with reference to the drawings, in which: Figure IA is a perspective view of a tactile ground surface indicator according to a first embodiment of the invention; 25 Figure lB is a top view of the indicator showing Figure IA; Figure 1 C is a cross-sectional elevation view taken through section J-J in Figure 1 B, showing deformable longitudinal ribs of a casing of the indicator; Figure 1 D is a cross-sectional elevation view taken through section K-K in Figure 1 B, showing channels of the casing of the indicator; 30 Figure 2A is a perspective view of the body portion of the tactile ground surface indicator according to both the first embodiment and a second embodiment of the invention; Figure 2B is a top view of the body portion shown in Figure 2A; Figure 2C is a cross-sectional elevation view taken through section D-D in -4 Figure 2B; Figure 2D is a rotated side view of the body portion shown in Figures 2A to 2C. Figure 3A is a perspective view of a tactile ground surface indicator according to the second embodiment of the invention; 5 Figure 3B is a top view of the indicator showing Figure 3A; Figure 3C is a cross-sectional elevation view taken through section F-F in Figure 3A; Figure 4A is a perspective view of an indicator portion of the indicators according to both the first and second embodiments; 10 Figure 4B is a top view of the indicator portion shown in Figure 4A; Figure 4C is a cross-sectional elevation view taken through section D-D in Figure 4B; Figure 4D is a view of detail E as shown in Figure 4C; and Figure 4E is a rotated side view of the indicator portion shown in Figures 4A to 4D. 15 A tactile ground surface indicator I according to a first embodiment of the invention, as depicted in Figure IA, comprises a body portion 3 which is moulded as a single piece from stainless steel, or machined from a solid bar of stainless steel, and, as can best be seen in Figures IC and I D, comprises an indicator portion 5 which will be positioned above a 20 ground surface, and a downwardly projecting portion in the form of a stem 7 which is receivable in a cavity, provided in the ground, which locates the indicator 1 in position. The indicator I further comprises a generally elongate casing 9, which is received over, and engaged with, the stem 7, the casing, which is for holding the indicator I in the 25 ground, being made from suitably deformable plastic, whereby it can deform against an annular wall of the cavity when the indicator I is driven into the cavity. The casing in this embodiment is moulded as a single piece of plastically-deformable plastic, and is moulded to, the stem 7. The casing 9 is configured as a cap which covers 30 the stem 7, the cap defining a recess II which is occupied by the stem 7. The casing 9 has a generally circular outer transverse cross-sectional profile. The exterior of the casing 9 is provided with a pair of opposed ridges or ribs 13 which extend linearly and longitudinally along the casing 9 from a top end of the casing 9. The -5 ribs 13 are provided at diametrically opposite positions on the casing 9. The ribs 13 protrude radially outwardly to be engageable with the annular wall of the cavity so as to deform against the wall when the indicator 1 is driven into the cavity, thus permanently locking the casing in the cavity and fixing the indicator 1 in the ground. To this end, the 5 outermost extents of the ribs 13 are spaced apart by a distance which slightly exceeds the diameter of the cavity. In an alternative embodiment, two pairs of ribs are provided the ribs of each pair lying at diametrically opposite positions on the casing to define planes which are perpendicular to 10 each other and which each form an acute angle of 60* with the plane in which the channels 17 are arranged. The lower end 15 of the casing 9 is tapered radially inwardly to facilitate driving of the indicator I into the ground. 15 The casing 9 further comprises a pair of longitudinally extending channels 17 which are disposed at diametrically opposite positions on the exterior of the casing 9 and extend generally linearly between the top and bottom ends of the casing 9. The channels 17 define spaces into each some of the material of the casing 9 can be displaced when the 20 casing 9 is driven into the cavity, under a radially inward pressure exerted by the cavity wall, giving rise to a radially outward biasing of the casing against the cavity wall, which assists retention of the indicator I in the ground. An annular channel 19 is provided in the exterior of the stem 7, the channel 19 defining a 25 space into which a complementarily configured, radially inwardly projecting portion 21, in the form of an annular rim, provided on the casing 9 in the recess 11, is received. The channel 19 defines a transversely extending portion which in turn defines an upper shoulder 23, providing a downwardly facing surface 25. The channel 19 also defines a further transversely extending portion which in turn defines a lower shoulder 27, providing 30 an upwardly facing surface 29. Similarly, the projecting portion 21 defines, on the casing 9, a transversely extending portion which in turn defines an upper shoulder 30, providing a downwardly facing surface 31. The projecting portion 21 also defines a further transversely extending portion -6 which in turn defines a lower shoulder 33, providing an upwardly facing surface 35. The downwardly facing surface on the casing 9 abuts the upwardly facing surface on the stem 7 to restrain the body 3 from upward movement relative to the casing 9. Similarly, 5 abutment of the downwardly facing surface of the stem 7 with the upwardly facing surface of the casing 9 prevents downward movement of the body 3 with respect to the casing, as does abutment of the upper end of the casing 9 with the underside of the indicator portion 5. Relative movement between the casing 9 and body 3 is thus prevented. 10 In other embodiments, the abutting surfaces need not face exactly upwardly and downwardly but rather need merely to have respective upwardly and downwardly facing components. As can be seen in Figures IC and ID, the recess 11 and stem 7, and particularly the 15 channel 19 projecting portion 21, are complementarily profiled such that the casing 9 is closely received over and fitted to the stem 7. As will be clear from Figures lB and ID, the channels 17 lie in an upright plane which is perpendicular to an upright plane in which the ribs 13 lie. The ribs 13 are thus provided 20 intermediate the channels 17 around the exterior of the casing 9. In the following description of the second embodiment, the same reference numerals as used in respect of the first embodiment will be used to designate common features. 25 The indicator 1' according to the second embodiment is shown in Figures 3A to 3C. It is identical to the indicator I of first embodiment in every respect except that the casing comprises opposed ridges or ribs 13' which, instead of extending longitudinally along the casing 9', extend around the casing 9'. The ribs 13' each extend between the channels 17 and are provided at opposite sides of a longitudinally-extending plane passing through the 30 channels, the ribs 13' thus defining a substantially annular deformable portion. The ribs 13' are provided approximately halfway down the casing. In an alternative embodiment, the casing comprises more than two ribs, constituting protuberances or protruding portions, extending therearound to define a substantially -7 annular deformable portion. In another alternative embodiment, the deformable portion is defined by deformable wings protruding from the casing. Because the casing 9/9' in each of the first and second embodiments is permanently fixed 5 to the stem 7, each indicator 1/1' is, advantageously, provided as a single or unitary item, whereby it is very quick and easy to install. In another embodiment, the exterior of the casing is configured with a plurality of radially outwardly projecting protuberances or protruding portions, in the form of ribs or ridges 10 which are arranged axially or longitudinally along the casing and which each extend therearound. The ridges or ribs provide a serrated longitudinal cross-sectional profile, affording the exterior of the casing a barbed configuration, with each ridge/rib extending upwardly and radially outwardly to define an annular edge. 15 The indicator portion 5 of each of the indicators 1 and ' according to the first and second embodiments is illustrated in Figures 4A to 4E. The indicator portion 5, which is provided as a single piece, has a generally circular transverse cross section and comprises a bottom portion 56, defining a downwardly facing surface 58 arranged to abut the ground surface, an upper portion 57 and a sloped or tapered smooth side wall 59, extending upwardly and 20 radially inwardly from the bottom portion 56 to the upper portion 57 and being inclined at an angle of approximately 350 to 45* from the downwardly facing surface 58. The diameter of the bottom portion is 35 millimetres. The upper portion 57 is defined by an upwardly facing surface 61, which is bounded by an 25 upper end of the side wall. The diameter of the upwardly facing surface 61, and thus the upper portion, is 25 millimetres. The distance between the downwardly facing surface 58 and the upper portion 57 is 4 to 5 millimetres. A gripping portion, provided by a circular lip 60, is provided at a radially outermost 30 position on the upper surface 61 and extends upwardly from the upper surface 61 to define a shoulder 62 which protrudes outside of the conical plane defined by the side wall 59, i.e. by extrapolation in the upwardly and radially inwardly direction in which the side wall 59 extends. The shoulder 62 comprises an edge 64 which lies outside of the conical plane. The lip 60 has a height of 0.5 millimetres.

-8 The protruding shoulder 62, particularly its edge 64, is able to catch and engage the sole of the person's shoe, particularly as moved against the tactile ground surface indicator in a direction having a sideways component, thereby preventing slipping, especially in the 5 general plane defined by the side wall, and conferring improved anti-slip characteristics to the tactile ground surface indicator. To enhance gripping further, a gripping pattern 63, is provided on the upper surface 61, the gripping pattern 63 comprising a plurality of concentric rings 65 extending upwardly from 10 the upper surface 61. The upper ends or tips of the rings, which define the uppermost extent of the gripping pattern 63, lie in a plane which is approximately 0.5 millimetres above the upper portion 57, or the plane defined by the upwardly facing surface 61 and are coplanar with the top end of the circular lip 60 and the upper edge 64. 15 The concentric rings 65 each have a thickness of approximately 0.5 millimetres, as does the lip 60. The concentric rings 65 have a radial pitch P of approximately 1.10 millimetres, each ring 65 thus having a thickness which is approximately 45% of the radial pitch P. Annular spaces 66 are defined between the rings 65, the annular spaces having a radial dimension of approximately 0.6 millimetres, as does the annular space defined between the 20 lip 60 and the outermost ring 65. Manufacture of the indicator I and ' according to the first and second embodiments firstly comprises moulding of the body portion 3, including the indicator portion 5, from stainless steel, or machining it from a solid billet of stainless steel. 25 With the body portion 3 arranged upside down, the stem 7 is then centrally positioned in a mould which defines the external configuration of the casing 9/9', the flat underside of the indicator portion 5 abutting a lower end of the mould to close that lower end. Molten plastic is then injected into the space between the mould and the stem, through a suitable 30 opening provided in the mould. The plastic is then allowed to cool and set, whereupon the finished indicator I/I' is removed from the mould. Because the casing 9/9' in each embodiment is fixed to the stem 7, each indicator 1/1' is, advantageously, inserted as a single or unitary item, whereby it is very quick and easy to -9 install. While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of 5 limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments. 10 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims

1. A tactile ground surface indicator, comprising a rigid indicator portion arranged to lie over a ground surface, and a rigid projecting portion extending from the indicator 5 portion to be receivable in a cavity formed in the ground, the indicator further comprising a casing applied to the projecting portion prior to receipt thereof in the cavity, the casing being deformable against a wall of the cavity upon insertion of the projecting portion into the cavity to retain the indicator. 10

2. An indicator according to claim 1, wherein the casing is closed at an end thereof which is lowermost when the indicator is installed.

3. An indicator according to claim 1 or 2, wherein the projecting portion is configured in the form of a stem. 15

4. An indicator according to any one of the preceding claims, wherein the indicator portion and projecting portion are integrally formed.

5. An indicator according to any one of the preceding claims, wherein the casing and 20 projecting portion are interlocked.

6. An indicator according to any one of the preceding claims, wherein the casing is moulded over the projecting portion. 25

7. An indicator according to any one of the preceding claims, wherein the casing is overmoulded to the projecting portion.

8. An indicator according to any one of the preceding claims, wherein the casing is permanently fixed to the projecting portion. 30

9. An indicator according to any one of the preceding claims, wherein the casing is formed with at least one protuberance which protrudes radially outwardly to be deformable against the cavity wall. - 11

10. An indicator according to claim 9, wherein the at least one protuberance comprises a pair of ribs arranged at opposite sides of the casing which extend in general alignment with the projecting portion. 5

11. An indicator according to claim 9, wherein the at least one protuberance comprises one or more ribs extending circumferentially around the casing to be deformable against the cavity wall.

12. A method of forming a tactile ground surface indicator, the method comprising: 10 providing a rigid body comprising an indicator portion arranged to lie over a ground surface and a projecting portion extending from the indicator portion to be receivable in a cavity formed in the ground; and prior to receipt of the projecting portion in the cavity, applying a casing to the projecting portion, the casing being deformable against a wall of the cavity upon insertion 15 of the projecting portion into the cavity to retain the indicator.

13. A method according to claim 12, wherein applying the casing to the projecting portion comprises moulding the casing over the projecting portion. 20

14. A method according to claim 12 or 13, wherein applying the casing to the projecting portion comprises overmoulding the casing to the projecting portion.

15. A tactile ground surface indicator substantially as hereinbefore described with reference to the accompanying drawings. 25

16. A method of forming a tactile ground surface indicator, substantially as hereinbefore described with reference to the accompanying drawings.