Emergency lighting

Details Emergency lighting Emergency lighting

1999-07-29

2001-08-21

Knight, Anthony (Department: 3628)

Aeronautics and astronautics

Aircraft structure

Passenger or crew accommodation

C040S542000, C040S570000, C362S084000, C362S153000

Reexamination Certificate

active

06276634

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to emergency lighting, typically for the interior of vehicles, and especially, but not exclusively, to emergency exit floor path lighting for aircraft.
BACKGROUND OF THE INVENTION
It is well known in aircraft to have strips of electrical lights mounted at floor level to guide passengers to the emergency exit doors of the aircraft. The strips of electric lights are powered by an emergency battery. Such systems work well, but they have some problems.
One problem is that they need regular servicing. The electrics needs checking periodically and bulbs need replacing. Maintenance of the floor-level emergency exit lights adds significantly to the cost of maintaining an aircraft. Also the power drain caused by running the lights adds to fuel costs.
A further problem is that if the emergency battery fails there is no guide lighting for the passengers leading them to the exits.
Another problem is that in the event of a crash the electrical wires connecting some or all of the floor level emergency lights can be broken, again meaning that some or all of the floor-level emergency lights are inoperative at just the time that they are most needed.
It is an aim of one embodiment of the present invention to alleviate at least some of these problems.
SUMMARY OF THE INVENTION
According to a first aspect of the invention we provide an emergency exit path lighting system comprising photoluminescent guide means adapted to indicate to a user a path for movement by emitting light photoluminescently.
Thus there is no external power supply to fail and thus the system may be fail safe. The system requires little or no special maintenance, and may simply require wiping or other similar cleaning. The system may be significantly lighter, cheaper and simpler to install than previous systems.
Preferably the guide means is on the floor, but may be elsewhere (e.g., on the side of seats).
Preferably the guide means is an elongate member.
Preferably the guide means comprises at least one, and preferably two elongate photoluminescent tracks mounted on or near the floor. The two photoluminescent tracks are preferably spaced apart so as to define a path within which the user should move. Each track preferably comprises a substantially continuous, or effectively continuous, strip of photoluminescent material. Alternatively a guide track may have photoluminescent regions, and non-photoluminescent regions which alternate. In a further alternative the photoluminescent track may comprise a row of photoluminescent dots, circles or the like.
Preferably the substantially continuous track provides a substantially continuous path of light from any point to an emergency exit. An advantage of this is that a person will never be lost as they will always have a path, to an exit, to follow. This “continuous cueing” concept is applicable to other situations.
Alternatively the substantially continuous track may provide a substantially continuous path of light from any point to the region of the emergency exit and electrical lighting means may provide lighting in the region of the emergency exit.
Preferably the system has a track which has a transparent or translucent cover which overlays a photoluminescent guide member. The photoluminescent guide member is preferably a relatively thin strip of material that is supported on a support member. The track may comprise a base member adapted to be secured to the floor, a cover member adapted to be releasably secured to the base member, and a photoluminescent member adapted to be sandwiched between the base member and the cover member. Preferably the photoluminescent member is a flexible strip. In one embodiment the support member supports the photoluminescent strip so that it can withstand being trodden upon. The support member preferably extends across substantially the full width of the photoluminescent strip. The photoluminescent member is preferably removable from the track and is replaceable. A track may be made of adjacent discrete lengths of profiled extrusion. The photoluminescent strip may also be provided in discrete lengths.
Alternatively, the photoluminescent strip may be permanently secured, for example with glue to either, the cover or the support member. In a further embodiment the photoluminescent strip may be co-extruded with either, or both, the cover, or the support member.
The cover member may have a ramped, or sloping, upper surface to facilitate the passage of wheeled vehicles such as trolleys.
Alternatively the cover member may have a low profile so that it provides only a minimal obstruction for wheeled vehicles, such as trolleys.
Preferably the track is laid in short sections. This has several advantages over using a continuous run of track. One advantage is that short runs are not as awkward to handle, another is that they are more resilient in the event of a crash of the vehicle in which the tracks are mounted. A continuous run may tend to be dragged away from the body of the vehicle in such a crash.
Alternatively the track may be laid in a continuous section.
Preferably the cover member of one section may overlap the base member of a neighboring section. An advantage of this is that neighboring sections are loosely coupled. A clip may be provided over the joints between the sections of the covering members. Alternatively the sections of the covering members may have no clip and simply butt against a neighboring section.
Preferably at each end of the track run there are provided end caps. The end caps may be used between the short sections of track.
Preferably to form angled joints the tracks are laid against each other. The sections may be mitered to form an angled joint.
Preferably a layer which is impervious to UV light is used to protect the photolurninescent layer. The UV protecting layer may be a strip mounted on top of the photoluminescent strip or may be a coating on the photoluminescent strip. An advantage of this is that UV light is prevented from reaching the photolurninescent strip, and thus the photoluminescent strip is not degraded by UV light. Also such a layer might additionally, or alternatively, prevent UV light from being emitted from the photoluminescent layer.
Preferably the layer impervious to UV light is made from a PVC based material or resin, but may be from any other suitable material. Preferably the layer impervious to UV light is translucent to light, or other electromagnetic radiation, other than UV light.
The transparent or translucent cover may have portions which are stained, painted, dyed or otherwise modified to change the light transmission properties of the cover. Preferably these portions are opaque. An advantage of such opaque portions is that they can be used to cover or mask poor cutting of the carpet. Alternatively the portions may not be opaque and may used to change the color of the light emitted from the photoluminescent strip. The method of modifying the light transmission properties may include inserting a colored filter underneath the cover or may include using a UV protective layer which modifies the color of the light passing through it.
According to a second aspect of the invention we provide a photoluminescent member comprising a base and a layer of photoluminescent material.
The layer may be cast onto the base. Alternatively, we may calender a thin layer, and apply that to the base.
Previously photoluminescent members have been made by mixing photoluminescent material with structural material and producing a calendered product. This has the photoluminescent material spread out throughout the depth of the member, when it is only needed at the surface. We have appreciated that by casting a photoluminescent layer on top of a base (or by having a thin calendered layer on top of a base) we can achieve better results.
Furthermore, we preferably provide (e.g. cast) two layers, or more, of photoluminescent material onto a base. This has been found to increase the light emitted, and is easier and cheaper than casting one thick layer. We can control the application of a thi

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