GB2430248A

GB2430248A - Lamp with changeable coloured filters

Info

Publication number: GB2430248A
Application number: GB0518751A
Authority: GB
Inventors: Barry Wright
Original assignee: Dorman Traffic Products Ltd
Current assignee: Dorman Traffic Products Ltd
Priority date: 2005-09-14
Filing date: 2005-09-14
Publication date: 2007-03-21
Also published as: GB0518751D0

Abstract

A lamp with at least one light emitting diode 22 and at least one coloured filter 26 which is locatable in relation to the LED 22 so as to provide light output of the desired colour from the lamp. Whereby the colour of the light output from the lamp is dependent on the filter 26 and not the LED 22. The lamp may have more than one LED 22 and more than one coloured filter 26, 28, with each filter being of a respective different colour and moveable into or out of a desired position, with respect to the light source, on a rotatable filter movement mechanism. The lamp may also have a lens 24 and a locking mechanism to fix the filter in position.

Description

LAM P

The present invention relates to a lamp/torch/flashlight and, in particular, to a lamp/torch/flashlight for use in the railway industry, for example for signalling. In the specification, the terms lamp, torch and flashlight are used interchangeably.

In the railway industry, it has long been standard practice for personnel (e.g. safety workers or train guards) to carry a signalling lamp. Typically such lamps are able to produce light of a number of different colours, at the selection of the user, such as usually red, green and/or yellow. It is known to have such a lamp which uses LEDs to produce the light output and a separate array of LEDs is provided for each colour desired i.e. one set of red LEDs, one set of green LEDs and one set of yellow LEDs.

However, the precise colours required by the railway industry can be difficult, if not impossible, to produce reliably using coloured LEDs. For example, the colour output of an LED will change depending on temperature and/or voltage, so it is difficult to guarantee a particular colour output in all circumstances.

Accordingly, the present invention aims to provide a lamp which overcomes or mitigates this problem.

In its most general sense, the present invention provides a lamp which includes at least one LED and also includes at least one coloured filter which is locatable in relation to the LED so as to provide light output of the desired colour from the lamp. In this way, the colour of the light output is dependent on the filter and not the LED, thereby overcoming the problem mentioned previously.

Typically the LED will be a white LED i.e. provide an output of white light, and there may be more than one such LED e.g. in one or more arrays. Also there may be more than one coloured filter, with preferably each filter being of a respective different colour. Each coloured filter may be locatable in a desired position so as to provide a light output from the lamp of an appropriate colour. The lamp may include means for moving the coloured filter(s) into and/or out of the desired position, and the means may be arranged so as to locate only one coloured filter in the desired position at a time (and/or to change it as desired for one of the other coloured filters) and/or to locate multiple coloured filters in the desired position simultaneously.

Typically, the lamp will include three coloured filters, one red, one green and one yellow, or may include four: red, green, yellow and white. The white filter may simply be colourless if the LED is white.

The lamp may include one or more lenses, and/or one or more of the individual filter(s) may also include lensing means.

Preferably the lamp includes selection means (such as a switch) by which the user may select the desired colour of light output for the lamp. Preferably the lamp also includes means for indicating to the user the particular colour selected. Such indicator means may be incorporated with the selection means. In one embodiment, the selection means is a rotary switch and in each switch position an appropriately coloured part of the switch is visible to the user, with the colour of the part indicating the colour of light output selected.

Preferably the lamp also includes locking means which are operable to prevent the lamp being turned on and/or off and/or the colour changed, as appropriate.

Preferably as the selection means is operated to change the colour of the light output of the lamp, the light output is briefly stopped between changes. This ensures that a mix of colours, or an undesired colour, is not accidentally displayed.

Preferably the lamp includes a bracket attached to the main body of the lamp. The bracket may be fixed to the main body or may be removably attached so that a different type of bracket can readily be substituted.

Typical types of bracket are: a bracket by which the lamp can be mounted on a train; a stand to enable the lamp to be placed in various positions; a magnetic bracket to enable the lamp to be attached to a metal surface; a clip so that the light can be easily attached to e.g. a belt or pocket; a bracket suitable for mounting the lamp on a cone; and a bracket suitable for mounting the lamp on a helmet.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: Fig 1 is a perspective view of a first embodiment of a lamp according to the present invention.

Fig 2 is a different perspective view of the lamp of Fig 1.

Fig 3 is a cross-sectional view along the line X-X in Fig 1.

Figs 4a and 4b show the selector switch of the lamp of Fig 1 in unlocked and locked positions respectively.

Fig 5 shows the filter selection mechanism of the lamps of Fig 1 and Fig 6.

Fig 6 shows a second embodiment of a lamp according to the present invention.

Fig 7 shows a partial view of the lamp of Fig 6.

The first embodiment of a lamp according to the present invention shown in Figs 1 and 2 includes a body 2 which has a base 4, a front wall 6, a rear wall 8 and a handle 10. Mounted on the body (in this case on part of the front wall 6) is a light portion 12.

Also mounted on the body (in this case on part of the rear wall 8) is a bracket 14. In this example, the bracket 14 is dimensioned so as to be suitable for mounting the lamp on a standard train fitting but, as mentioned previously, the bracket could be designed for other purposes and could be removably attached so different brackets can be substituted.

The base 4 of the housing may also be used to hold a battery (not shown) for the lamp. In this example, access to the battery compartment is via a front aperture 16, but of course other suitable arrangements could be devised. The location of the relatively heavy battery in this area helps to lower the centre of gravity of the lamp and therefore to improve its stability.

The lamp also includes a switch 18 and a selector 20 (seen most clearly in Figure 2) . The switch could be for turning the lamp on and/or off, but in this example is for locking and/or unlocking the selector 20. The selector 20 is, in this example, a rotary switch for selecting one of several coloured filters to change the colour of light output of the lamp. Other types of selector could be devised. The operation of the light portion 12, switch 18 and selector 20 will now be described in more detail with reference to the cross- sectional view shown in Figure 3.

Fig 3 shows the light portion (generally indicated as 12) mounted on part of the front wall 6. The light portion 12 consists essentially of an LED 22 as a light source and a lens 24 to focus or control the light in a suitable way to produce the desired output beam. In this example, the light source is a single white LED but, as mentioned previously, the light source could be multiple LEDs arranged in one or more arrays and of one or more desired colours.

Located in front of the LED 22 (i.e., in this example, between the LED 22 and the lens 24) is a first filter 26.

This filter 26 is of an appropriately chosen colour (for example, one of red, green and yellow) and so, when it is in the position shown, the light output of the lamp will be determined by the colour of the filter 26.

Also seen in Figure 3 is a second filter 28, which could be chosen to be a different colour to the first filter 26. The lamp includes means for moving the filters 26 and 28 so that filter 28 may be located in a suitable position (in this case, in the position currently occupied by filter 26) 30 as to provide a differently coloured light output from the lamp. In this example, the means for moving the filters is a rotary arrangement, seen more clearly in Figure 5) which is operated by the user using the selector 20. The lamp may include more than two coloured filters, for example one each for red, green, white and yellow, as seen in Figure 5. The white "filter" may simply be an empty aperture, to allow the white LED light to pass through.

In this embodiment, the selector 20 is rotatable e.g. around the axis A-A shown in Figure 3. When it is rotated by the user, it in turn rotates the filter movement mechanism 30 shown in Figure 5. The rotation of the filter movement mechanism 30 causes the individual filters to rotate so as to be locatable in the desired position(s) This particular example of the selector 20 is designed so as to have one or more fingers, in this case four: 32, 34, 36 and 38 (seen in Figure 2) . The user rotates the selector 20 by pulling or pushing on one or more of the fingers. One or more of the fingers may include one or more surfaces, all or part of which can be suitably coloured. In this example, one face 40 of finger 36 and/or one face 42 of finger 32 are coloured with a colour to approximately match one of the filters. For example, one or both of these surfaces may be red. In this way, when the selector 20 is in the position shown in Figure 2, the user can easily see the red face(s) and this position of the selector will have been chosen to correspond to a red filter being in the appropriate position in relation to the LED 22 so that the light output of the lamp is red.

Similarly, other faces of the or other finger(s) may also be coloured so that when the selector is in other of its positions, an appropriate colour is seen by the user which matches the coloured output of the lamp in that position.

In addition, the lamp may include means for preventing the changing of the colour of the light output of the lamp e.g. in this example means for preventing the movement of the filters by movement of the selector 20.

One example of such means is shown most clearly in Figures 4a and 4b, where the effect of the operation of switch 18 on selector 20 is shown. Switch 18 is moveable (in this case along axis B-B shown in Figure 3) and its movement engages or disengages a locking mechanism which locks selector 20 in position and prevents its movement.

In this example, the locking mechanism is a finger 50 which includes a tooth 52 which (in the locking position) engages a notch 54 in part of the selector 20. In this example, the selector 20 includes a plurality of notches 54, so that the selector can be locked in one of a plurality of positions. The switch 18 may be biased to the locking position, so that the user must activate the switch 18 in order to be able to move the selector 20.

As mentioned previously, the lamp may also include means for preventing light being output from the lamp during all or part of the time in which one filter is being changed for another. This is to prevent a mix of colours being output from the lamp at the same time. In this embodiment, such means is provided by the arrangement of the selector switch 20 and/or the filter movement mechanism 30. When the filter movement mechanism 30 is being operated in order to change the position of the filters, the arrangement is such that only one filter or part of one filter at a time is located in front of the LED 22. There is a position between changes of filters in which no part of any filter is located in front of the LED 22, at which time there will be no light output from the lamp. Preferably, the filter mechanism 30 is also lockable in that position i.e. the lamp is effectively off. In this example, this is again achieved using the locking mechanism shown in Figures 4a and 4b. As can be seen, several of the notches 54 are located in positions (e.g. 60, 62) in which the selector can be locked part way through a filter change operation.

Preferably the selector is operable by the user using only one hand. More preferably, both the switch 18 and the selector 20 are operable by the user using only one hand. In this example, the user would use the thumb of one hand to operate the switch 18 and the fingers of the same hand to operate the selector 20.

Figure 6 shows a second embodiment of a lamp incorporating some aspects of the present invention. As will be immediately apparent, this embodiment of the lamp could be physically smaller than the embodiment of Figure 1 and is intended to be more easily carried by railway personnel.

In the embodiment of Figure 6, the lamp includes a body to which is attached a bracket 72. In this example, the bracket 72 is a stand which is moveable with respect to the body 70 so as to be able to support the body 70 in various different positions. As mentioned previously, the bracket 72 may be removably attached to the body 70 so that it can be substituted by other types of bracket.

Part of the body 70 also houses a battery (not shown) and, in this example, the battery is inserted into the body through aperture 76.

Attached to part of the body 70 is a light means 78, which could be similar in structure and operation to the light means 12 of the first embodiment described above, but in this case is slightly different. The main structural difference is that, in this embodiment, there is no direct equivalent of the locking switch 18 or the selector 20, although either or both of these could be included in this embodiment.

Instead, a wheel is incorporated somewhere on the lamp (for example, a thumb wheel in this case in e.g. position 82 indicated on Figure 6) which would control movement of the filters in a similar manner to that described previously.

However, in either or both lamp embodiments, other ways of achieving a mechanism by which the filter(s) may be moved will be apparent to the skilled person.

For example, the outer housing of the light means 12 could be arranged so as to be rotatable. The rotation of the outer housing would cause movement of filter(s) within the light means in a similar manner to that described previously. As before, the filter(s) may be located in a filter movement mechanism as shown in Figure 5. Such a rotatable outer housing (a bezel) could be included in the embodiment of Figure 1 or Figure 6.

Whether a movement of the filters is achieved by movement of the light housing 80 or a thumb wheel (not shown), one advantage is again that the user may operate the lamp with only one hand. Also, since the embodiment of Figure 6 may use the same internal filter mechanism as shown in Figure 5, the lamp will again be in an "off" position between filter changes as described previously.

Figure 7 shows more clearly the inside of the lamp of Figure 6, with the front part of the housing removed.

The whole of the thumb wheel 82 can be seen and it will be readily appreciated that rotation of the thumb wheel 82 causes the filter(s) (in this case four filters 84, 86, 88 and 90) to rotate, in a similar manner to that described previously.

The above embodiments and illustrations of preferred features are intended to be examples of the present invention and variants and modifications of those embodiments, such as would be readily apparent to the skilled person, are envisaged and may be made without departing from the scope of the present invention.

Claims

1. A lamp which includes at least one LED and also includes at least one coloured filter which is locatable in relation to the LED so as to provide light output of the desired colour from the lamp.

2. A lamp according to Claim 1 wherein the LED provides an output of white light.

3. A lamp according to Claim 1 or Claim 2 including more than one LED.

4. A lamp according to any of the above claims including more than one coloured filter.

5. A lamp according to Claim 4 wherein each filter is of a respective different colour.

6. A lamp according to Claim 4 or Claim 5 wherein each coloured filter is locatable in a desired position so as to provide a light output from the lamp of an appropriate colour.

7. A lamp according to any of the above claims including means for moving the coloured filter(s)into and/or out of a desired position. e..

8. A lamp according to Claim 7 wherein the means are.. : arranged so as to locate only one coloured filter in the desired position at a time and/or to locate multiple coloured filters in the desired position simultaneously.

S

9. A lamp according to Claim 4 wherein the lamp includes three coloured filters, one red, one green and one yellow.

10. A lamp according to Claim 8 wherein the lamp includes four coloured filters: red, green, yellow plus white or colourless.

11. A lamp according to any of the above claims including one or more lenses, and/or wherein one or more of the individual filter(s) also includes lensing means.

12. A lamp according to any of the above claims including selection means by which the user may select the desired colour of light output for the lamp.

13. A lamp according to Claim 12 wherein the lamp also includes means for indicating to the user the particular colour selected.

14. A lamp according to any of the above claims including locking means which are operable to prevent the lamp being turned on and/or off and/or the colour * : changed. S..

S

15. A lamp according to Claim 12 wherein the selection means is arranged so that as it is operated to change the colour of the light output of the lamp, the light output is briefly stopped between changes.

16. A lamp substantially as any one embodiment herein described with reference to the accompanying drawings.