GB2390669A

GB2390669A - A signal apparatus having a heated housing

Info

Publication number: GB2390669A
Application number: GB0323808A
Authority: GB
Inventors: Andrew S M Denholm; Barry Wright
Original assignee: Dorman Traffic Products Ltd
Current assignee: Dorman Traffic Products Ltd
Priority date: 1999-11-26
Filing date: 2000-11-22
Publication date: 2004-01-14
Anticipated expiration: 2020-11-22
Also published as: GB0323808D0; GB2390669B

Abstract

A signal apparatus which comprises a housing 4 including a light source (Fig. 3, 16) and a transparent cover 10, the housing being attachable to a support element 6 which can carry further housings, via attachment means on the housing which thermally connects the housing and the support element, where the apparatus has a wound wire resistance heater (Fig.4, 30) wound around a portion of the housing adjacent the attachment means and in thermal contact with the attachment means such that heat generated by the heater is transmitted to the support element and then onwards to the further housings. The light source may be LEDs.

Description

SIGNAL APPARATUS

_ The present invention relates to a signal apparatus and more particularly, but not exclusively, to a signal apparatus for use in a transport system and to signalling or warning lights.

Recently, significant attention has been focussed on the problems of phantom signalling, particularly associated with railway signalling apparatus such as ground position lights. The problem with these signal apparatus is that phantom signals can be generated which give the appearance that a lamp is showing a particular signal, when in fact, this perceived signal is being caused by extraneous light entering the lamp and being reflected out therefrom. This can cause great confusion to drivers.

Also, it is a well established requirement in the field

of transport systems to require signal or warning lights of different colours on the same signal apparatus to indicate to drivers of vehicles, trains etc. a particular condition of the system ahead. Signal or warning apparatus for train drivers which may for example show

either a red (for 'danger" or "stop") or white (for "clear" or "go") are one particular example. Hitherto the dual colour capability is provided by two different lamps mounted adjacent one another, the whole unit often being referred to as a "ground position light" ((ill).

However, as the demand for greater efficiency of signalling, and the provision of greater numbers of coloured light possibilities for different signalling purposes, increases, there exists the problem of providing existing ground position light units with the required multi- coTour capability. Normally this would need to be done by replacing the GPL units in their entirety, for example if an existing dual colour lamp unit was needed to be converted to a three colour lamp unit, and this is obviously disadvantageous as regards cost, time and labour.

Accordingly, it is an aim of the present invention to overcome or ameliorate the problem of phantom signalling.

According to a first aspect of the present invention there is provided a signal apparatus including a light source housed in a housing, the housing including a substantially transparent cover portion, wherein the cover portion is angled with respect to a plane normal to

the housing longitudinal axis such that, In use, extraneous light striking a surface of the cover portion is reflected in a direction different to the direction in which light IS emitted from the signal apparatus by the signal apparaLs light source. Preferably, IN use the cover portion is angled with respect to a vertical plane such that extraneous light is reflected in a downward direction towards the ground.

By extraneous light, it is meant light which originated from a source, or was reflected by a surface, outside of the signal apparatus.

Having the cover portion angled with respect to a plane normal to the housing longitudinal axis results in a reduced likelihood of a phantom signal being generated.

In particular, when the cover portion is angled with respect to a vertical plane (i.e. when the housing longitudinal axis is horizontal) such that any extraneous light striking the outwardly facing surface of the cover portion is reflected in a downward direction this results in a signal apparatus in which the only way a phantom signal can be generated is from extraneous light emitted from a source, or reflected by a surface, at ground level near to the signal apparatus.

Additionally, any light that is reflected by the cover portion may polarlsed, and thus would be of a significantly reducer) intensity.

Preferably, the cover portion is angled with respect to the plane normal to the housing longitudinal axis (e.g. with respect to a vertical plane) by an angle of 2511 to 6511. In a preferred embodiment, a lens is located between the light source and the cover portion, wherein the lens is located such that it is parallel to the cover portion.

Preferably, the lens includes a plurality of lens elements. The lens is preferably located such that it is parallel to the cover portion.

Preferably, the light source includes a plurality of light emitting diodes (LEDs) carried on a printed circuit board (PCB). More preferably, the PCB is arranged parallel to the cover portion. In embodiments where the PCB is arranged such that it IS parallel to the cover portion, the LEDs are preferably parallel to the longitudinal axis of the housing, ie. the LEDs are angled with respect to the PCB.

A further problem associated with using LEDs as the light

source in a signal apparatus is that of keeping the apparatus free from ice and misting. Typical signal apparatus use one or more filament bulbs as the light source. These tend to draw a relatively large current compared with LEDs and generate a significant amount of heat when illuminated. Thus, when using one or more filament bulbs as the light source, Icing and misting problems typically do not occur. However, when the signal light source is an LED light source, icing and misting problems may occur, since LEDs generate an insignificant amount of heat.

It is known that LEDs draw relatively little current compared with a filament bulb. Thus, when replacing a signal apparatus including a filament light source with a signal apparatus including an LED light source, there is a "surplus" current capacity that can be used.

Therefore, according to a second aspect of the present invention there is provided a signal apparatus including a housing having a substantially transparent cover portion, a light source, wherein the housing has a heater in thermal contact therewith.

The heater Is preferably a resistance heater and more preferably a wound wire resistance heater which is most

preferably wound around a portion of the housing.

In a preferred embodiment, one or more signal apparatus is/are carried on a support element. The resistance wrc is preferably wound around a portion of the housing adjacent the support element. The housing and the support element are preferably thermally connected one to the other such that heat generated by the heater may be transmitted to the support element and then optionally from the support element to the or each further signal apparatus carried on the support element. Thus, signal apparatus In which the heater is not activated, may nevertheless be heated via the support element by a signal apparatus in which the heater is activated.

The signal apparatus heater preferably includes a control means to selectively activate and deactivate the heater.

More preferably the control means activates the heater when the signal light source is illuminated and deactivates the heater when the siqual light source is not illuminated.

Typically, the signal apparatus has a lens located between the light source and the cover portion.

According to a third aspect of the present invention

there is provided a signal apparatus comprising the signal apparatus of the first aspect of the invention, together with a heater as described with respect to the second aspect of the present Invention.

According to a fourth aspect, the Invention provides a signal apparatus including a signal light, the signal light including first light means for emitting light of a first colour and second light means for emitting light of a different colour. Thus, the signal 1lght IS Operclble in at least two operating states, wherein, in use, light emitted by the signal light operating in a first operating state has a substantially different colour to light emitted by the signal light operating in a second operating state.

Preferably, the signal light appears as a single or substantially continuous light source to the viewer when viewed under normal operating conditions.

Typically, a signal apparatus has two, three or four signal lights.

Preferably, the signal light includes two or more light means, each light means capable of emitting light of a _ _, lllllIL 1()U.

Typically, each light means includes a respective array of 1lght source elements, the arrays being spatially intermingled with each other.

Preferably, individual flight source elements of each array are arranged respectively adjacent individual light source elements of the other array.

Preferably the light sources of each array of the light or lights are conventional LEDs as used in existing conventional signalling lamps of transport systems. The LEDs are suitably mounted on a circuit board (again, as is conventional), but with each differently coloured array of LEDs being powered independently and/or selectively, depending upon which colour array is required to be lit at any particular time. In practical embodiments of the invention the individual LEDs (or other light source elements) of each array within the one or more lights are positioned respectively adjacent one another, one light source element of one array being positioned adjacent a light source element of another array. These adjacent respective light source elements may for example he positioned over all in an equispaced arrangement, or

alternatively the respective light sources of respective arrays may for instance be clumped to-tether in a more irregular fashion.

the or each fight of the signal apparatus of Lee invention may incorporate either a single clear lens for the purpose of transmitting the different coloured lights to a relevant user of the transport system or alternatively it/they may incorporate specific optics for that purpose, examples of which arc already known in the art of traffic and t-.rain signalllng and warning lamps.

In preferred practical embodiments of the invention the signalling or warning apparatus may incorporate a single multi-colour light or two or even more such multi-

colour lights, the or each light having the multiple arrays of different colour light source elements provided therein. As a typical example, it IS envisaged that the invention is particularly applicable to the provision of a dual col.our single light where otherwise the replacement of a single colour light with two discrete single colour lights would otherwise be necessary.

One such practical example of the applicability of the

present invention is with reference to the signal apparatus according to the first, second, or third aspect

of the present invention, where there may be a requirement for at least one of the individual lights of that apparatus to have a dual colour capability, in order to avoid having to replace one of those lights with two conventional differently coloured lights, as might be the case in the further development of transport safety systems. Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fi.gure 1 is a side elevational view of a first signal apparatus according to the present invention; Figure 2 is a front elevational view of the signal apparatus shown in figure 1; Figure 3 IS a cross section along A-A of one of the signal elements shown in figure 2; Figure 4 is a magnified portion of part of the housing shown in figure 3i Fi.gure 5 shows a sectional view a second exemplary preferred embodiment of signal apparatus according to the

invention; and Figure 6 shows, in schematic form only, the face view of the interior of Just one of the lights of the signal apparatus shown in Figure 5.

Elqures 7A and 7B show two existing signal apparatus; and Figure 7C shows how the apparatus in Fig. 7B can be modified according to an embodiment of the present invention. A signal light, in the context of this specification,

means a light which can give an indication to a viewer.

The viewer may be, for example, the driver of a train or the driver of a road vehicle. The signal light appears as a single or substantially continuous light source to the viewer when viewed under normal operating conditions.

In particular, preferably a signal light should be visible from a large distance (in relation to the direction of the signal light), in order to give the viewer time and space in which to react to the signal. A signal apparatus may include one or more such separate signal lights In order to communicate one or more indications to the viewer.

Figures 1 and 2 show what is known as a ground position signal 2 for use with a railway transportation network.

The ground position signal 2 consists of four signal elements 8 carried on a common support clement or base plate 6 in a desired arrangement. The ground position signal 2 is located, as its name suggests, at ground level at an appropriate position on the railway network.

The individual signal elements 8 of the grounds position signal 2 may emit light of different colours to indicate information to a train driver.

Each signal element 8 includes a housing 4, including an aluminium cylinder 5 of which one end defines a plane parallel to the base plate 6 (ie normal to the longitudinal axis of the cylinder 5) and the other end defines a plane which is angled with respect to the plane defined by the base plate 6, and a transparent glass cover 30. In use, the base plate 6 is vertical and the longitudinal axis of the housing cylinder 5 is horizontal. The signal element 8, shown in more detail in figures 3 and 4, consists of a backplate 12 and the housing 4 (commonly referred to as a hooded housing). As shown in figure 3, the housing 4 comprises an upper cylinder housing portion 42, a lower cylinder housing portion 99

and the transparent glass cover 10. The upper cylinder housing portion 42 extends a greater distance from the backplate titan the lower cylinder housing portion 44 such that the transparent cover 10, arranged between the distal ends of the Eloper and lower cylinder hocusing portions 42, 44, Is at an angle of about 301' relative tc' a vertical plane parallel. to a plane defined by the backplate 12.

Housed within the housing 4 IS a printed circuit board (PCB) 14 carrying a plurality of light emitting diodes (LEDs) 16. The PCB 14 is fixed within the housing such that it is parallel to the glass cover 10. The LEDS 16 are arranged on the PCB 14 such that they are parallel to the longitudinal axis C of the housing 4. Thus, the LEDS 16 are carried on the PCB 14 at an angle of about 60Q to the plane defined by the PCB 14. The PCB 14 is connected to an electrical power source (not shown) vita an LED control means (also not shown) well known in the art of LED light sources.

Also housed in the housing 4 are an outer lens element 22 and an inner lens element 20, each containing a plurality of grooves and ridges arranged in a predetermined configuration to focus the light emitted by the LEDs 16 into the desired output pattern. The inner and outer

lenses 20, 22 are also arranged parallel to the glass cover 10.

The housing 4 includes a heater 30 Shown in more detail in figure 4. The heater 30 comprises a plurality of windings of a nickel chromium electrical resistance wire 32 which is wound in a channel defined by an inwardly facing surface 34 of the housing body 4 and a heater carrying member 36 filch that the windl.ngs of the resistance wire 32 are in thermal contact with the housing body 4.

The resistance wire 32 is electrically connected to a heater control means (not shown).

The housing body 4 is thermally connected to the base plate 6 via the heater carrying member 36 and the signal element backplate 12. In this arrangement, the heater, when activated, heats the housing body 4 and also transmits a proportion of the heat energy given out to the base plate 6. Figure 5 is a cross sectional view through an embodiment of a signal apparatus and housing similar to that shown in Figure 3. However in this embodiment there are effectively two arrays of LEDs 50, 52. Each array contains a plurality of LEDs and In this example the LEDs of each array are all the same colour

i.e. the LEDs of one array are red and the LEDs of the other array are white. As can be seen more clearly an Figure 6, one LED from the first array is paired with an LED from the second array and the overall effect is a combined array of LED pairs.

In further embodiments (not shown) there may be more than two arrays 1.e. three, four, five etc. and the LED from each array may be mutually arranged in any suitable fashion. As will be appreciated from the previous description, the

light functions so that only the LEDs of one of the arrays are operated at any given time and the operation of the light may be switched between the arrays.

This has the effect that the light is seen to change colour i.e. in this example to go between red and white and vice versa.

Figures 7a and 7b show two examples of current train signal lights. Figure 7a shows a four aspect light in which, when the lower two red lights are lit this indicates that the train is to stop and when the upper two white aspects are lit this Indicates that the train is to proceed with caution. In Fissure 7b, when the -uppe-

and lower white aspects are lit the train F S to proceed with caution whereas when the bottom white and red aspects are lit the train is to stop.

Figure 7c gives an example of how a four aspect 1lght according to the present invention may be implemented using a three aspect body. Effectively the two lower lights are each replaced by a light as shown in Figure 5.

When the two lights are operated so that they are both red this indicates that the train is to stop and when the two lights are operated so that they are both white this indicates that the train is to proceed with caution.

Other arrangements, numbers and colours of lights will be apparent to those skilled in the art.

As will be appreciated by the skilled person, suitable lenses or optics may be included in front of the LED arrays in order to ensure that the light is directed in an appropriate manner for the application in question.

These preferred embodiments have been described by way of example and it will be apparent to those skilled in the art that many alterations can be made that are still within the scope of the invention.

Aspects and optional features of the invention are set out in the n. :mbered paragraphs below.

1. A signal apparatus inc-ludlng a signal light, the signal light including first light means for emitting light of a first colour and second light means for emitting light of a different colour.

2. A signal apparatus according to paragraph 1, wherein each light means includes a respective array of light source elements, the arrays being spatially intermingled with each other.

3. A signal apparatus according to paragraph 2 wherein individual light source elements of one array are each arranged respectively adjacent individual light source elements of the other array.

4. A signal apparatus according to paragraph 2 or paragraph 3 wherein the light source elements are LEDs mounted on a circuit board, each array being independently powerable.

5. A signal apparatus according to any one of paragraphs i to 4 wherein the signal light includes three

or more light means, each light means capable of emitting light of a different colour.

6. A signal apparatus including a light source housed in a housing, the housing including a substantially transparent <over portion, wherein the cover portion is angled with respect to a plane normal to a longitudinal axis of the housing such that, in use, extraneous light striking a surface of the cover portion is reflected in a direction different to the direction in which light is emitted from the signal apparatus by the signal apparatus light source.

7. A signal apparatus according to paragraph 6 wherein, in use, the cover portion is angled with respect to a vertical plane such that extraneous light is reflected in a downward direction towards the ground.

8. A signal apparatus according to paragraph 6 or paragraph 7 wherein, in use, extraneous light reflected from the cover portion is polarized.

9. A signal apparatus according to any one of paragraphs 6 to 8 wherein the cover portion is angled with respect to the plane normal to the housing longitudinal axis by an angle of 25 to 65 .

10. A signal apparatus according to any one of paragraphs 6 to 9, including a lens located bctwccn the light source and the cover portion, wherein the lens is located such that it is parallel to the cover portion.

11. A signal apparatus according to paragraph 10 wherein the lens includes a plurality of lens elements.

12. A signal apparatus according to any one of paragraphs 6 to 11 wherein the light source includes a plurality of LEDs carried on a printed circuit board.

13. A signal apparatus according to paragraph 12 wherein the printed circuit board is arrayed such that it is paral]e,l, to the cover portion.

14. A signal apparatus according to paragraph 13 wherein the LEDs each have a longitudinal axis parallel to the longitudinal axis of the housing.

15. A signal apparatus including a housing having a light source therein and a substantially transparent cover portion, wherein the apparatus has a heater in thermal contact with the housing.

16. A signal apparatus according to paragraph 15 wherein the heater is a wound wire resistance heater which Is wound around a portion of the housing.

17. A signal apparatus according to paragraph 16, the signal apparatus being attachable to a support element, for carrying one or more signal apparatus, via attachment means on the housing to thereby thermally connect the housing and the support element, wherein the wound wire resistance heater is wound around a portion of the housing adjacent the attachment means.

18. A signal apparatus according to any one of paragraphs 15 to 17, further including control means for selective activation and deactivation of the heater.

19. A signal apparatus according to paragraph 18 wherein, in use, the control means activates the heater when the light source is illuminated and deactivates the heater when the light source is not illuminated.

20. A signal apparatus according to any one of paragraphs 15 to 19 wherein the light source is a LE] light source.

21. A signal apparatus according to any one of

paragraphs 15 to 20 with a lens located between the light source and the cover portion.

22. A signal apparatus according to any one of paragraphs 15 to 21 including the features of any one of paragraphs 1 to 5.

23. A signal apparatus according to any one of paragraphs 15 to 21, lnc] uding the Matures of any one of paragraphs 6 to 14.

24. A signal apparatus according to any one of paragraphs 1 to 5, including the features of any one of paragraphs 6 to 14.

25. A signal apparatus according to any one of paragraphs 1 to 5, including the features of any one of paragraphs 6 to 14 and the features of any one of paragraphs 15 to 21.

26. A signal apparatus according to any one embodiment substantially as hereinbefore described with reference to Figs. 1 to 6 and Fig. 7C.

Claims

1. A signal apparatus including a housing having a light source therein and a substantially transparent cover portion, the signal light: being attachable to a support element, for carrying one or more further signal lights, via attachment means on the housing to thereb thermally connect the housing and the support element, wherein the apparatus has a wound wire resistance heater wound around a portion of the housing adjacent the attachment means and in thermal contact therewith, such that heat generated by the heater IS transmitted to the support element and to the or each further signal light.

2. A signal apparatus according to Claim 1, further

including control means for selective activation and deactivation of the heater.

3. A signal apparatus according to Claim 2, wherein, in use, the control means activates the heater when the light source is illuminated and deactivates the heater when the light source is not illuminated.

4. A signal apparatus according to any one of claims 1 to 4, wherein the light source is an LED light source.

5. A signal apparatus according to C1aZm 4, wherein the signal light includes a first array of LEDs for emitting light of a first coloilr and a second array of LEDs for emitting light of a different: colour.

6. A signal apparatus according to any one of the preceding claims, including a support element.

7. A railway signal apparatus including a signal apparatus according to any one of the preceding claims.

8. A ground position light including a railway signal apparatus according to claim 7.

9. A signal apparatus according to any one embodiment substantially as hereinbefore described with reference to Figs. 1 to 6 and Fig. 7c.