GB2564890A

GB2564890A - Illumination unit

Info

Publication number: GB2564890A
Application number: GB1712052.8A
Authority: GB
Inventors: Wood Michael; John Holloway Michael
Original assignee: Salop Holdings Ltd
Current assignee: Salop Holdings Ltd
Priority date: 2017-07-26
Filing date: 2017-07-26
Publication date: 2019-01-30
Anticipated expiration: 2037-07-26
Also published as: GB2564890B; IE20180221A1; GB201712052D0

Abstract

A pedestrian crossing illumination unit comprises a globe 11 of translucent material and a light guide 22 for transmission of light from an LED light source 19. The light guide is positioned to provide a high visibility illuminated zone which has a level of illumination that is higher than that of adjacent surfaces of the globe. The light guide may be positioned outside the globe 11 (Figs. 3-8).

Description

This invention relates to an illumination unit and in particular, though not exclusively, to an illumination unit for use as part of a Belisha beacon assembly.

Conventionally an illumination unit for use as part of a Belisha beacon assembly comprises a globe of translucent material within which a light source is provided.

The intensity of the illumination provided by the light source needs to be sufficient to ensure that in day time the beacon is clearly and distinctly visible to both pedestrians and road users whilst at the same time not being of such a great intensity as to present a nuisance to occupants of nearby dwellings during periods of darkness.

Various proposals have been advanced for dealing with the aforementioned problem, such as providing a level of illumination of varying intensity in response to changing ambient light conditions or providing shields to protect nearby dwellings from sight of the beacon.

Although these proposals can work with some degree of success, there remains a particular difficulty in ensuring that there is a sufficiently bright illumination and warning to pedestrians and road users in conditions of bright sunlight.

The present invention seeks to provide an improved pedestrian crossing illumination unit that has an enhanced ability to be clearly visible, either continuously or intermittently, during conditions of bright ambient light.

In accordance with one aspect of the present invention an pedestrian crossing illumination unit comprises a globe of translucent material whereby substantially all of the outer surface of the globe appears illuminated when internally illuminated, and said illumination unit further comprising a light guide for transmission of light from a light source, said light guide being positioned to provide a high visibility illuminated zone of a high level of illumination which is higher than that of adjacent surfaces of the globe.

The illuminated zone may, for example, be a ring shaped zone or a curved zone such as a part circular zone. However other zone shapes may be provided.

The light guide may comprise solely a single guide of solid cross-section or may comprise a tubular shaped light guide, such as a guide of circular crosssectional shape.

The globe preferably is of a spherical shape apart from positions at which it is in contact with a support post. The globe preferably is of a uniform colour, at least in the absence of internal illumination.

The light guide may comprise a bundle of small cross-section solid or tubular light guides. A single light guide of tubular shape may be formed from a plurality of individual light guides such as optical fibre guides arranged substantially parallel with one another and secured together to define a tubular shape, such as a cylindrical shape. A light guide may comprise a sheet of light transmitting material shaped, for example rolled, to provide a guide of a required shape.

Preferably the light source is an LED light source.

The light guide may be of a tubular form and may be positioned within the globe whereby one end of the guide is positioned to receive light from a light source, which may be within the globe, and the other end faces and may be in contact with an internal surface of the globe or spaced from the globe and positioned to direct light to the internal surface of the globe. Thus the tubular light guide may be employed to provide the globe with a high visibility ring of light that appears at a surface of the globe. The guide may positioned such that, when in use, the ring lies in a substantially vertical plane whereby the illumination presents a high visibility ring which points in a direction to face oncoming traffic.

In addition or as an alternative to providing a high visibility ring of light the light guide may be employed to display a message, such as “don’t walk” on the surface of the globe. The guide may be shaped to correspond with the message or a mask may be employed over an end of the light guide to result in the required shape, e.g. a message, appearing at the globe surface.

As an alterative or in addition to a light guide that transmits light through the translucent globe, a light guide may be arranged to illuminate a collar (known also as a ring or a shroud) that extends in known manner around at least a part of the outer surface of the globe. That collar may be illuminated by a light guide which directs light to the collar from a light source which may be positioned within the globe or externally thereof. The light source for an external collar, as in respect of a light source for a light guide within the globe, preferably is an LED light source.

The invention provides also an illumination unit assembly comprising the combination of an illumination unit and a support post which in use supports the illumination unit above ground level.

The illumination unit assembly may comprise one or more illumination units. An illumination unit of a type in accordance with the present invention may be supported at an end of the support post or at a position between the ends of the post.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:Figure 1 is a side view, part cut away, of an illumination unit in accordance with a first embodiment of the present invention;

Figure 2 is an exploded perspective view of part of the illumination unit of Figure 1;

Figure 3 is a perspective view of an illumination unit in accordance with a second embodiment of the invention in combination with the top end of support post;

Figures 4 and 5 are respectively side and front views of the illumination unit and post assembly of Figure 3;

Figure 6 is a perspective view of an illumination unit in accordance with a third embodiment of the invention secured mid length along part of a support post, and

Figures 7 and 8 are respectively side and front views of the illumination unit and post assembly of Figure 6.

In a first embodiment of the invention, shown in Figures 1 and 2, an illumination unit 10 for attaching to the support post (not shown) of a Belisha beacon comprises two semi-spherical mouldings 11 of yellow translucent plastics and which form a spherically shaped globe 12 when sealingly secured together.

Each semi-spherical moulding is welded to a chassis member 13 which is secured to a respective one of a pair of post brackets 14 by means of which the pair semi-spherical mouldings and their associated chassis members 13 may be brought together to surround the support post in a known manner.

Additionally the illumination unit comprises a pair of internal supports 15, each referred to on the drawings as a door. Each support is secured to a respective bracket 14 and extends through a central opening 16 of a respective one of the chassis members 13 to define a substantially circular mounting face 17.

At least one of the mounting faces 17 supports an LED light unit 18 which comprises a circular array of individual LEDs 19 and, within the circular array, a globe illumination light 20 which also may be comprised of LEDs.

The circular array of LEDs 19 is covered by one end 21 of a cylindrical light tube 22 formed of optically clear material. The length of the light tube is selected such that in the assembled illumination unit the other end 23 abuts or may be close to the internal surface of the semi-spherical moulding 11.

The illumination unit 10 may comprise only one said light tube but if there is a requirement for high intensity rings of light to be displayed in two or more directions, such as two opposite facing directions, two or more said light tubes may be provided, and each may be secured to a respective support such as or similar to the support 15.

In addition to the globe illumination unit 20 supported by the mounting face 17 to illuminate the globe surface area that lies within the end 23 of the light tube 22 there is provided a further light source (not shown) for the purpose of illuminating those regions of the globe surface which are external of the globe surface area within the tube end(s) 23.

In use of the illumination the light from the circular array of LEDs, of a suitably high light output, results in the outer surface of the globe displaying a high visibility ring of greater illumination intensity than areas of the globe not directly contacted by the end(s) 23 of the light tube(s) 22.

Although for this embodiment of the invention it has been described that the light tube 22 is of a cylindrical shape, thereby to present at the globe surface a high intensity illuminated area of a ring shape, the invention envisages that a light tube or guide or plurality thereof of other shapes may be provided, for example to display a pedestrian symbol or text, at a relatively high illumination intensity.

Although most of the light from the circular array 19 of LEDs will be directed through the light tube to the outer tube end 23, some light may stray out through the internal and external cylindrical wall surfaces of the tube. That may advantageously reduce the intensity of illumination needed from a light source that provides general illumination from the globe. However particularly if the illumination unit is to be operated in a manner in which the circular array of LEDs may be switched on or off, that stray light may detract from achieving provision of a substantially uniform level of illumination of the globe areas within and surrounding the aforementioned ring of high intensity illumination.

To address the requirement for a substantially uniform level of general illumination the present invention further teaches that the inner and/or outer surfaces of the light tube may be covered with a shield material to eliminate unwanted stray light. The surface of the shield material facing the light tube and/or the opposite facing surface may be of reflective material.

Although in this embodiment the globe is of translucent yellow plastics, and which is particularly suitable for providing an illumination unit of a Belisha beacon, other materials and other colours or optically clear materials may be employed. Thus for a so called centre island beacon, the globe may present a generally white appearance and a high intensity illuminated ring or other shape may be white or may be of a contrasting colour such as by the use of coloured LEDs or coloured material for the light guide.

In accordance with a second embodiment of the invention (see Figures 3 to 5) an illumination unit 30 for attaching to a support post 31, typically to the top 32 of the post, comprises a globe 33 of translucent plastics material and which is surrounded in part by a collar 34 which provides illumination in addition to that provided by a light source within the globe. The collar in this embodiment is secured relative to the globe to lie in a plane, in use typically a vertical plane, which is parallel with the length of the post.

The collar 34 is aligned with the post such that it lies in a plane which contains the longitudinal axis of the post. The collar extends around a substantial part of the globe but comprises two circumferentially spaced end regions 35, these each being slightly spaced from a flange-like housing 40 secured to the post and relative to which the globe is secured.

The collar 34 comprises substantially cylindrically shaped radially inner and outer opaque sections 36, 37 which extend between substantially planar translucent end faces 38, 39 to define light diffusing regions.

The radially inner surface of the outer section 37 and the radially outer surface of the inner section 36 of the collar are highly reflective, for example by applying highly reflective material to those surfaces. Alternatively the surface of the opaque material from which the collar is formed may provide a highly reflective surface.

An LED light source is provided within the housing 40 and two light guides 45 extend from the LED light source at diametrically opposite positions 41,42 of the housing, in alignment with the collar end regions 35, such that light from the light source is directed into the respective collar end regions 35. In consequence of the reflective properties of the inner and outer collar sections 36, 37 that incoming light is then distributed around the collar to illuminate the light diffusing regions of the planar end faces 38, 39.

In a third embodiment of the invention (see Figures 6 to 8) the construction of the second embodiment is modified so as to be adapted for use with a globe provided at a mid position between ends of a support post. In this variation the illumination unit 50 comprises a globe 51 surrounded in part by two collar sections 52 each of arcuate shape. Each collar section 52 extends between a housing 54 of a construction similar to that of the housing 40 of the second embodiment, and a retention flange 55 which is secured to the post 56 and provides support for the globe 51. Each collar section 52 is adhesively secured to the globe and the housing 54 is provided with an LED light source and light guides for transmission of light to lower ends 57 of each of the collar sections in a manner corresponding to that described in respect of the second embodiment.

Although for the second and third embodiments of the invention it has been described that the light guide transmits light from a light source within a housing to the end region of a collar or collar section, without the light guide necessarily extending into the collar or collar section, the light guide or a part thereof may extend into the collar or collar section. In addition to a light guide which terminates at a collar or collar section end region, one or more light guides may be provided to extend within a collar or collar section. Two or more light guides within a collar or collar section may terminate at spaced apart positions thereby to act in combination with the reflective internal surfaces of the collar or collar section to achieve an enhanced uniformity of distribution of light for illumination of or transmission of light through the collar end faces.

Having regard to the foregoing it will be appreciated that the present invention readily provides an improved pedestrian crossing illumination unit for which light can be efficiently directed so as to provide a high visibility illuminated zone, such as a ring or part circular zone of a high level of illumination which is higher than or otherwise contrasts with that of adjacent surfaces of the illumination unit globe.

Claims

1. A pedestrian crossing illumination unit comprising a globe of translucent material whereby substantially all of the outer surface of the globe appears illuminated when internally illuminated, and said illumination unit further comprising a light guide for transmission of light from a light source, said light guide being positioned to provide a high visibility illuminated zone of a high level of illumination which is higher than that of adjacent surfaces of the globe.

2. An illumination unit according to claim 1 wherein the light source for providing light for transmission through the light guide is an LED light source.

3. An illumination unit according to claim 1 or claim 2 wherein the globe is of a spherical shape apart from positions at which it is adapted for contact with a support post.

4. An illumination unit according to any one of the preceding claims wherein the globe is of a substantially uniform colour in the absence of internal illumination.

5. An illumination unit according to any one of the preceding claims wherein the illuminated zone is a ring shaped zone.

6. An illumination unit according to any one of claims 1 to 4 wherein the illuminated zone is of part circular shape.

7. An illumination unit according to any one of the preceding claims wherein the light guide comprises solely a single guide of solid or tubular cross-section.

8. An illumination unit according to any one of claims 1 to 6 wherein the light guide comprises a bundle of solid or tubular light guides.

9. An illumination unit according to any one of the preceding claims wherein the light guide comprises a sheet of light transmitting material deformed to a non-planar shape.

10. An illumination unit according to any one of the preceding claims wherein a surface of the light guide between the ends thereof is provided with a shield material to inhibit transmission of light from said surface.

11. An illumination unit according to claim 10 wherein the surface of the shield material facing the light guide and/or the opposite facing surface is of reflective material.

12. An illumination unit according to any one of the preceding claims wherein the light guide is positioned within the globe with one end of the guide positioned to receive light from a light source and the other end facing an internal surface of the globe.

13. An illumination unit according to claim 12 wherein the light source is within the globe.

14. An illumination unit according to claim 12 or claim 13 wherein the end of the light guide facing the internal surface of the globe is in contact with said internal surface.

15. An illumination unit according to claim 12 or claim 13 wherein said end of the light guide facing the internal surface of the globe is spaced from the globe and positioned to direct light to said internal surface of the globe.

16. An illumination unit according to any one of claims 12 to 15 wherein the light source comprises a circular array of individual LEDs.

17. An illumination unit according to any one of claims 1 to 11 wherein the light guide is positioned to transmit light to a collar that extends around at least a part of the outer surface of the globe.

18. An illumination unit according to claim 17 wherein the light guide directs light to the collar from a light source positioned with the globe.

19. An illumination unit according to claim 17 or claim 18 wherein the light guide extends into the collar or a section thereof.

20. An illumination unit according to claim 19 wherein two or more light guides extend within the collar or a collar section and terminate at spaced apart positions.

21. An illumination unit assembly comprising the combination of an illumination unit according to any one of the preceding claims and a support post which in use supports the illumination unit above ground level.

22. An illumination unit assembly according to claim 21 wherein a support post supports an illumination unit at an end of the support post.

23. An illumination unit assembly according to claim 21 or claim 22 wherein the support post supports an illumination unit at a position between the ends of the post.