AU2020256296A1

AU2020256296A1 - Improvements in illuminated road studs

Info

Publication number: AU2020256296A1
Application number: AU2020256296A
Authority: AU
Inventors: Christine ARMENIAN
Original assignee: Cape 11 Pty Ltd
Current assignee: Cape 11 Pty Ltd
Priority date: 2019-10-18
Filing date: 2020-10-12
Publication date: 2021-05-06
Also published as: SG10202010289RA

Abstract

An illuminated road stud is described including: an outer case; a light module housing; a light module including at least one light source; the light module is positioned at least partially inside the light module housing; and the at least one light source sits inside an air filled cavity which is sealed by a region of potting compound. 1/6 10 16 18 12 14 Fig1

Description

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IMPROVEMENTS IN ILLUMINATED ROAD STUDS

Technical Field The present invention relates to improvements in illuminated road studs and in particular concerns improvements which resist damage to the electronic components of the road stud due to ingress of water.

Background to the Invention Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians. Mechanical devices have been be used which are raised or recessed into the road surface and aid in providing information to drivers or pedestrians about the roadway or pavement at night or during times of low visibility. Traditional devices of these types include cat's eyes, and retro-reflective road studs. In more recent times attempts have been made to improve the effectiveness of road markings by providing road markings, such as road studs, which include powered light sources such as LEDs. Illuminated road studs typically have a protective outer case to resist damage by vehicles using the road, and to protect the inner electronic components from damage. However, it has been found that water can sometimes make its way into the case and cause damage and failure to the electronic components of the road stud. There remains a need to provide improved illuminated road studs which have increased resistance to water damage.

Summary of the Invention In a first aspect the present invention provides an illuminated road stud including: an outer case; a light module housing; a light module including at least one light source; the light module is positioned at least partially inside the light module housing; and the at least one light source is located inside an air filled cavity inside the light module housing, and the air filled cavity is sealed by a region of potting compound. The region of potting compound may surround the light module to seal with the inside surface of the light module housing. The potting compound may be transparent.

The road stud may further include a pair of insulated wires which provide power to the light source, and an interruption is provided in the insulation of each wire to resist water ingress along the wires by capillary action. The interruption may be provided by a printed circuit board. The interruption may be provided by at least one ferrule. The at least one ferrule may have crimpable wire receiving regions at each end, separated by a solid region. The region of the interruption in the wires may be embedded in a potting compound. The wires may be gel-filled wires. In a second aspect the invention provides an illuminated road stud including: an outer case; at least one light source is located inside the case; and a pair of insulated wires which provide power to the light source; and wherein an interruption is provided in the insulation of each wire to resist water ingress along the wires by capillary action.

Brief Description of the Drawings An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a road stud; Figure 2 is a top view of the road stud of figure 1; Figure 3 is a side view of the road stud of figure 1; Figure 4 shows the gel-filled light module of the road stud of figure 1; Figure 5 illustrates an interruption in the power supply wires of the road stud of figure 1; Figure 6 is an underside view of the lid portion of the road stud offigure 1 with a portion of potting compound removed; and Figure 7 is a cross-sectional view of an alternative way of providing an interruption in the power supply wires by using a special type of ferrule.

Detailed Description of the Preferred Embodiment Referring to figures 1 to 3, an illuminated road stud 10 is shown including a case which is made up of a metal base portion 14 and a metal lid portion 12. The lid portion 12 includes two apertures 16, 18 for emitting light from a lighting module (not visible) which is housed inside the lid portion 12. The base portion 14 is designed to be embedded into the surface of a road or pavement so that the lid portion 12 lies slightly proud of the road surface. Power supply wires are also embedded into the road surface and enter the base portion beneath the road surface through an aperture in the base portion. The light emitting apertures 16, 18 are oriented so that they face towards oncoming traffic in use. Several studs 10 are usually arranged together in a pattern in the road surface and are wired together on the same power supply wires to operate in unison. The light emanating from the apertures serves to warn or inform oncoming vehicles of the presence of a hazard or other road feature such as a lane marking or pedestrian crossing. Referring to figure 4, the lighting module 20 of the road stud 10 is shown removed from the road stud. The module 20 includes a transparent housing 22 in which is mounted a PCB which is populated with two regions of light emitting diodes (LEDs) 24, 26. The regions of LEDs 24, 26 align with the apertures 16, 18 when the lighting module is installed in the lid 12 of the road stud 10. Power cables 42 provide power to the LEDs. Housing 22 has been partially filled with a potting compound in the form, of a transparent bicomponent potting gel 30 with very high dielectric and thermal characteristics. A suitable gel is Religel PlusTM produced by HellermannTyton (www. HellermannTyton.com). The gel surrounds the PCB to seal around the PCB and against the inside surface of the housing 22 and covers the power cables 42. Air-filled cavities in the form of air pockets 32, 34 are left so that the lenses of LEDs 24, 26 are not surrounded by potting gel. The air pockets 32, 34 are purposely provided within the module so that the LED intensity and photometric specifications of the LEDs are not affected by the potting compound. Covering the power cables 42 and sealing around the lighting module with the potting compound gel prevents the change in air pressure (typically caused by heat from turning the LED on or from environmental changes) that is responsible for initiating capillary action (water ingress). The process of introducing the transparent potting gel is undertaken by initially partially filling up the module housing with an appropriate amount of liquid gel by way of a small hole in the rear face of the module where the power cables enter the module. The module is then inverted (to adopt the orientation shown in figure 4) so that the

LEDs 24, 26 are oriented uppermost on the module. Any liquid gel that may have been in contact with the lenses of the LEDS flows down and away from the lenses and the gel is allowed to set. The amount of gel used is controlled so that in the resulting partially filled state, the gel does not cover the lenses of the LEDs. If any residual gel remains on the LEDs after the filling process has been completed then this will not materially affect the light output of the LEDs. The is because clear gel is used, and any residual gel that might be left behind will in any event only form a very thin layer. Referring to figure 5, a technique is shown for providing an interruption in the outer insulation which surrounds each power supply wire 42. The power supply wires 42 which emanate from the light module are soldered to a printed circuit board (PCB) 40 and a further secondary pair of power supply wires 44 lead away from the PCB 40 to be attached to a power source. The interruption in the insulation breaks the direct flow of pressure along the inside of wires 42. Wires 42, 44 are preferably formed from gel filled wire.

The road stud is assembled as follows:

1. Partially fill light module housing with a transparent potting compound to leave an air pocket surrounding the LEDs in the light module; 2. Locate light module inside lid portion 12 so that the LEDs are oriented to emit light from apertures 16, 18; 3. Attach PCB 40 in power supply wires 42 leading to the light module and attach gel-filled wires 44 to PCB 40; 4. Surround light module and PCB 40 with a second region of potting compound.

Referring to figure 6, the assembled lid portion 12 of the road stud 10 is shown from the underside. The second region of potting compound 50 is shown. The second region of potting compound 50 does not need to be transparent and surrounds both the light module 20 (not visible in figure 6 because it is hidden in the potting compound) and the PCB 40. A suitable product for the second region of potting compound is SikaLastomer -710 produced by Sika (www.sika.com). In the figure, a portion of the second region of potting compound 50 has been broken away to expose the PCB 40 for illustration purposes. In an assembled unit, neither the light module 20 nor PCB 40 are visible as they are encapsulated in the second region of potting compound 50.

In the above described embodiment, the interruption in the insulation of the power supply wires was provided by inserting a PCB in the wires. In other embodiments the interruption may be provided by inserting special ferrules in the wires. Referring to figure 7, cylindrical ferrules 60 are shown joining the pairs of wires 42, 44. The ferrules 60 are formed from metal and both have crimpable wire end receiving regions 64 provided at each end. Between the crimpable regions 64 is a solid region 62. As a result, there is no through hole in the ferrule. To assemble, the wire ends 42, 44 are stripped of insulation and are introduced to the wire end receiving regions 62 of the ferrules 60 and crimped in place. This arrangement prevents water travelling under pressure through the ferrule and further resists introduction of water into the electronic components of the road stud. The ferrules 60 are potted in the region of potting mix 50, as for the PCB arrangement described above.

It can be seen that embodiments of the invention have improved resistance to water ingress to prevent water from damaging the light source and other electronic components of the road stud.

Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated. Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit of the present invention.

Claims

CLAIMS:

1. An illuminated road stud including: an outer case; a light module housing; a light module including at least one light source; the light module is positioned at least partially inside the light module housing; and the at least one light source is located inside an air filled cavity inside the light module housing, and the air filled cavity is sealed by a region of potting compound.

2. An illuminated road stud according to claim 1 wherein the region of potting compound surrounds the light module to seal with the inside surface of the light module housing.

3. An illuminated road stud according to either of claim 1 or claim 2 wherein the potting compound is transparent.

4. An illuminated road stud according to any preceding claim which further includes a pair of insulated wires which provide power to the light source, and an interruption is provided in the insulation of each wire to resist water ingress along the wires by capillary action.

5. An illuminated road stud according to claim 3 wherein the interruption is provided by a printed circuit board.

6. An illuminated road stud according to claim 3 wherein the interruption is provided by at least one ferrule.

7. An illuminated road stud according to claim 6 wherein the at least one ferrule has crimpable wire receiving regions at each end, separated by a solid region.

8. An illuminated road stud according to any one of claims 4 to 7 wherein the region of the interruption in the wires is embedded in a second region of potting compound.

9. An illuminated road stud according to any one of claims 4 to 8 wherein the wires are gel-filled wires.

10. An illuminated road stud including: an outer case; at least one light source is located inside the case; a pair of insulated wires which provide power to the light source; and wherein an interruption is provided in the insulation of each wire to resist water ingress along the wires by capillary action.

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