DE20309405U1 - Underground corridor lights for airport runways have light emitting diode light sources - Google Patents

Abstract

An underground corridor light installed in a surface housing (52) comprises a light source and holder, optics, a plug and a supply cable. The light source is an LED and the optics placed in the light exit path. The top of the housing forms a part of the cover (14) opening in a recess (26) in the cover.

Description

Inset lights

The invention relates to an in-ground light according to the preamble of claim 1.

A complex signaling system of permanently installed lighting elements, known as airport lights, is used to ensure the safe operation of an airport. In addition to marking the runways, the lighting systems also perform numerous additional functions, such as providing visual information about the approach angle for pilots approaching the landing. The most technically complex components in such systems are the so-called in-ground lights. The in-ground lights are used on runways and also on the access and exit routes, known as taxiways, and are embedded in the ground or subsurface.

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The typical design of an in-ground light is such that a pot-like insert is embedded in the floor and secured. In the base of the insert there is a lead-through for a cable that is connected to a power supply. The light source is usually a halogen lamp that is attached to a suitable holder that is connected to a lid-like closure of the insert. Suitable optics ensure that the light from the halogen lamp is emitted at a desired angle.

In-ground lights are subject to strict requirements. For example, the elevation above the road surface is limited to 12.5 mm, for example. It must also be ensured that no moisture penetrates into the interior of the unit and impairs the electrical connection or the function of the light source and the optics. In addition, an in-ground light must be able to be driven over with a high load without causing damage to the housing or the lamp.

Known in-ground lights have a number of disadvantages. One is the relatively short service life of halogen lamps, which is around 4000 operating hours, which corresponds to two maintenance intervals per year. Another disadvantage is the very high heat development of the halogen lamps, which requires a minimum size of the in-ground light to prevent overheating.

The sharp increase in air traffic in recent years has led to a sharp increase in the density of aircraft on the access and departure routes and, in some cases, to a

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Increase in travel speeds ("fast taxiways", "block traffic"). These changes increase the risk of collisions and runway incursions. To increase safety, it is known to use stop lines, so-called stop bars, which can be switched from the tower using a stop signal from special in-ground lights. Depending on the intended use, the lights must reach their full light output very quickly after activation. A maximum permissible switching time of 1 second is considered for this. Due to the system-immanent switching times from the tower to the in-ground light, 0.4 to 0.6 seconds are to be estimated; the maximum switching time cannot therefore be achieved with halogen lamps. These deliver their full lamp output after 1.4 seconds at the earliest. This results in a total switching time of at least 1.8 seconds for halogen lamps.

The invention is based on the object of creating an in-ground light that can be built smaller, has a longer service life and can be more easily maintained or repaired.

This problem is solved by the features of patent claim 1.

In the in-ground light according to the invention, at least one light-emitting diode (LED) is provided as the light source. Its holder is arranged in a closed housing which contains a light passage opening and an optical system. The housing is arranged in a recess in the cover part which is open at the top, preferably fittingly received in the recess, with the top of the housing forming part of the traversable top of the cover part.

Due to the very small design of LEDs, the optical periphery in the in-ground light can be made much smaller, thus meeting the requirement for a lower road surface elevation. Furthermore, the service life of an LED is significantly longer than that of a halogen lamp and is around 80,000 operating hours, which corresponds to a normal service life of 10 years.

The switching time of an LED is negligible, so that the total switching time from triggering in the tower to the build-up of the light output is about 0.6 seconds, thus easily meeting the intended requirements for stop lines, for example.

With conventional underfloor lights, the power is supplied via a complex high-voltage supply. At larger airports, electrical series circuits with outputs of up to 70 kVA are used. The associated control units are correspondingly extensive and complex. All essential electrical components are high-performance special components. For underfloor lights with an LED as the light source, the electrical power requirements are significantly lower. They can usually be met by standard electrical components. Cables with a significantly reduced cross-section can also be used for the supply, which is particularly important at larger airports. In larger airports, cables are laid up to 1000 kilometers long. The installation with an underfloor light according to the invention is therefore drastically reduced in terms of effort. The risk during installation and maintenance work is also significantly lower, as no high voltages have to be handled.

The housing accommodating the optics and at least one LED can be designed as a module that can be used for a wide variety of underfloor lights, e.g. in a single or multiple arrangement, whereby, for example, in a multiple arrangement, two housings are accommodated in corresponding recesses on opposite sides of a partition wall and have a radiation direction to opposite sides at a predetermined angle to the ground.

As already explained, the top of the housing forms part of the top of the lid-like closure for the in-ground light. According to one embodiment of the invention, the top of the housing is flat, with the top of the lid part sloping down to the edge at an angle following the housing in order to form a smooth transition for the wheel driving over it. The exit of the beam from the housing via the light exit opening is supported within the lid part, with the beam being able to exit at a predetermined angle via a recess in the lid part. This creates a gap in the area of which the wheel driving over is not supported. However, this gap is relatively narrow, so that the housing or its optics and the LED are not endangered when driving over it.

According to one embodiment of the invention, the housing is cuboid-shaped. It goes without saying that various geometric shapes are conceivable, although simple shapes are naturally preferable for manufacturing reasons. In a cuboid-shaped housing, the light exit opening is provided, for example, in a slope on the top of the housing, with the light passage opening being able to accommodate a prism as an optic.

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According to another embodiment of the invention, the housing is preferably formed from a lower housing part and an upper housing part, which can be firmly and tightly connected to one another, for example by screwing, gluing or welding. According to another embodiment of the invention, the housing is preferably fastened in the recess of the cover part by screwing. This fastening preferably provides for the arrangement of screws on the underside of the cover part so that no moisture can penetrate into the interior of the housing via screw holes.

When installing an underfloor light according to the invention, the housing can first be prefabricated with contents, with the prism and LED mounted and then the upper and lower parts of the housing connected to one another. The lower part of the housing naturally has a leadthrough for a cable to supply the LED. A formed part that supplies the LED with the desired voltage and current is preferably accommodated in the pot-shaped insert, in which there is already sufficient space and for a sufficient cable length that allows the cover part to be lifted off before a plug connection for the supply line is disconnected.

The LED is preferably mounted on a suitable circuit board. It is commercially available in this form. The LED is also provided with a suitable optic. Such a circuit board is preferably fixed in the lower part of the housing by means of a screw connection. The prism in the housing is geometrically adapted to the conditions of the underfloor heating.

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ers and is preferably designed to be elongated and held in place by means of a frame which is fixed in the housing. According to another embodiment of the invention, the prism has a circumferential shoulder which rests against a circumferential shoulder in the light exit opening, the frame ensuring that the shoulders remain in engagement with one another. A distance is maintained between the frame or the prism and the LED which prevents damage to the LED in the event of minor deformations which may occur when driving over the in-ground light.

In the above, reference is mostly made to an LED in the singular. It is understood that three or more LEDs can be arranged in the housing in order to provide the desired light output. In any case, the invention is not limited to the number of LEDs.

The invention will be explained in more detail below using an embodiment shown in drawings:

Fig. 1 shows a flush-mounted light according to the invention in plan view,

Fig. 2 shows a section through the representation according to Fig. 1 along 2-2,

Fig. 3 shows an exploded view of the in-ground light according to Fig. 1 and 2,

Fig. 4 shows a perspective view of the underfloor light according to Fig. 1,

Fig. 5 shows an exploded view of a housing with parts included,
Fig. 6 shows a section through a housing.

In Fig. 2 it can be seen that a cylindrical, pot-shaped insert 10 is embedded in the ground, for example the floor of a runway or roadway at an airport, the upper edge of which is flush with the surface. The insert 10 has an extension in the upper area, which forms a shoulder 12. A carrier part 14 is inserted in this area, which has a circumferential flange 16 that rests on the shoulder 12. The cylindrical section 18 of the carrier part 14, which is smaller in diameter, is inserted into the insert 10 and sealed by means of a seal that is embedded in an annular groove 20. As can be seen in particular from Figs. 1 and 3, semicircular recesses 22 open towards the edge with a flat base, in which a bore 24 is made, are formed diametrically in the flange 16. The cover part 14 is firmly screwed into the insert 10 via the holes 24, whereby threaded holes are provided in the area of the shoulder 12 into which the fastening screws are screwed.

The structure of the carrier part 14 is shown in more detail in Fig. 3. Two recesses 26, 28 with a rectangular cross section can be seen, made from above on either side of an intermediate wall 30, which is arranged in a diametrical plane. The recesses 26, 28 have a flat base 32, 34, in which screw holes are formed. In addition, there is a through opening 36 or 38 approximately in the middle of the base 32 or 34.

The recesses 26, 28 are partially set into a flat surface 40 and partially into a conical surface 42 which surrounds the flat surface 40. The conical surface 42 extends to the edge of the cover part 14. Between the recesses 26, 28 and the edge of the carrier part 14, a radial recess 44 or 46 is also formed in the top of the carrier part 14. Since the bottom of the recesses 44, 46 is flat and horizontal, but lies in the area of the conical surface 42, the depth of the recess decreases towards the edge and becomes zero there.

The recesses 26, 28 serve to accommodate two housings 50, 52 or modules that are suitably accommodated in the recesses 26, 28, as can be seen in Fig. 2. The housings 50, 52 are approximately cuboid-shaped, but have a slope on the top towards a side wall, as can be seen at 54. A light passage opening 56 is formed in the area of the slope 54. The structure and the interior of the housing 52 are explained in more detail below with reference to Figs. 5 and 6. The structure of the housing 54 is identical, so that the explanations naturally also apply to the housing 54.

The housing 52 consists of an upper housing part 58 and a lower housing part 60. The upper housing part 58 has a ceiling section 62, two opposite side walls 64 and a front wall 66. The lower housing part 60 has a bottom section 68 and a rear wall 70. The upper housing part 58 is plugged onto the lower housing part 60 in a manner as can be seen by looking at Fig. 5 and 6 together. The rear wall 70 and the front wall 66 are relatively thick, so

that the upper and lower housing parts 52, 60 can be firmly connected to one another by a screw connection, as is indicated by the screws 72, 74. However, it is also possible to screw the upper part 58 to the lower part 60 using screws only from the underside, so that the top of the housing 52 does not have to have screw holes. This may be more advantageous for sealing reasons. The upper and lower housing parts are connected to one another in a sealed manner, and seals can be inserted into the abutting surfaces (not shown). The base section 68 has an opening 76 for the sealed passage of a cable (not shown). The opening 76 is aligned with the opening 38 in the cover part 14 (Fig. 2).

An elongated prism 78 has a circumferential shoulder 80. The prism 78 is inserted into the light passage opening 56 of the housing upper part 58, with its circumferential shoulder 80 resting against a complementary shoulder 82 in the light passage opening 56. A sealing compound can also be provided in this area, as indicated at 84, so that the passage of foreign bodies or liquid into the housing interior is prevented.

A frame 86 is located on the rear side of the prism 78, which has an elongated projection 88 on the underside that can be inserted into a complementary slot 90 in the bottom section of the lower housing part 60. In the lateral and upper area, the frame 86 engages in a groove 92 in the upper housing part 58 and is thus fixed on all sides when the housing parts are screwed together.

This also fixes the prism 78, in particular by pressing its shoulder 80 against the counter shoulder 82 in the housing.

In Fig. 5, an arrangement 94 of three LEDs 96 can be seen, which are provided with a corresponding optic (not shown in detail) and are mounted together on a circuit board 98. The circuit board 98 is screwed against the front of the rear wall 70 of the housing base 60, which is not shown in detail. As can be seen from Fig. 6, the frame 86 is at a certain distance from the LEDs, so that even if the housing deforms to a certain extent under high loads, the LEDs are not affected.

The electrical supply to the LEDs 96 is via a cable (not shown) which is sealed through the opening 76. The cable is indicated at 100 in Fig. 2, which is connected to a converter unit 102 which is located inside the insert 10 and which is connected to the supply cable 104 of the supply system. LEDs are known to require a low voltage and a very low current.

During assembly, the housings 50, 52 are pre-assembled according to their structure according to Figs. 2 and 6. They are then inserted into the recesses 26, 28 of the cover part 14, whereby the supply cables are inserted through the openings 38 of the recesses 26, 28. The cables are connected to the cable coming from the converter unit 102 by a suitable plug connection (not shown). In addition, the housings 52, 56 are screwed to the cover part 14, whereby

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the screws are passed from the underside of the cover part 14 through screw holes in the cover part. However, this is not shown in the figures. The cover part 14 is then placed on the insert 10 and screwed there, as already described.

As can be seen, the top of the cover section 62 of the upper housing part 58 forms part of the flat surface 40 of the cover part 14. The exit of the light passage opening 56 extends from the top obliquely downwards to the bottom of the recess 44, 46 of the cover part, so that it is sufficiently protected against tires driving over it. The prism 78 and the structure behind it are thus sufficiently protected.

As can be seen from Fig. 2, a beam emerges from the structure on opposite sides of the cover part 14 at a shallow angle to the ground in order to create a desired signal fire.

As can be seen, the housings 50, 52, which can be regarded as modules, can be quickly assembled and disassembled so that maintenance work can be carried out within a very short time.

Claims (15)

1. Underfloor light which fits into a pot-shaped housing inserted into the ground, with at least one light source, a holder for the light source which is attached to a pressure-resistant support part which closes the receiving head at the top, an optic for the light source which can be connected via a plug connection to a supply cable which is inserted into the housing, characterized in that the light source is an LED ( 96 ), the holder is formed by a closed housing ( 50 , 52 ) which holds the LED ( 96 ), into which a connecting line piece for the LED ( 96 ) is introduced in a sealing manner and which has a light passage opening ( 56 ) to which the optic arranged in the housing ( 50 , 52 ) is assigned and the housing ( 50 , 52 ) is arranged in a sealing manner and fastened in an upwardly open recess ( 26 , 28 ) of the support part ( 14 ), wherein the upper side of the housing ( 50 , 52 ) forms part of the traversable upper side of the cover part ( 14 ). 2. In-ground light according to claim 1, characterized in that the upper side of the housing ( 50 , 52 ) is flat and the upper side of the cover part ( 14 ) slopes down beveled towards the edge adjacent to the housing. 3. Underfloor light according to claim 1 or 2, characterized in that the cover part ( 14 ) has two recesses ( 26 , 28 ) for two identical housings ( 50 , 52 ) which are arranged on opposite sides of a central partition wall ( 30 ) and the arrangement of the optics of the housings ( 50 , 52 ) is such that the LEDs radiate in opposite directions at an angle to the ground. 4. In-ground light according to one of claims 1 to 3, characterized in that the housings ( 50 , 52 ) are cuboid-shaped. 5. In-ground light according to claim 1 and 4, characterized in that the light passage opening opens outwards in a bevel ( 54 ) of the upper side of the housing ( 50 , 52 ) and accommodates a prism ( 78 ) as an optic. 6. In-ground light according to one of claims 1 to 5, characterized in that the housing ( 50 , 52 ) has an upper housing part ( 58 ) and a lower housing part ( 60 ) which can be firmly and sealingly connected to one another. 7. In-ground light according to claim 6, characterized in that the connection is made by means of screwing, gluing, welding or the like. 8. In-ground light according to one of claims 1 to 7, characterized in that the housing ( 50 , 52 ) is fastened in the recess ( 26 , 28 ) by screwing. 9. In-ground light according to claim 8, characterized in that the screws are screwed from the underside of the cover part ( 14 ) into threaded holes in the housing ( 50 , 52 ). 10. Underfloor light according to one of claims 5 to 9, characterized in that the light passage opening ( 56 ) is located in a depression ( 44 , 46 ) adjacent to the recess ( 26 , 28 ) which is open towards the edge of the cover part ( 14 ). 11. In-ground light according to one of claims 5 to 10, characterized in that a circuit board ( 98 ) holding an LED ( 96 ) is fixed to the lower housing part ( 60 ) by means of screws and the prism ( 78 ) is fixed in the upper housing part ( 58 ) in the light passage opening with the aid of a frame ( 86 ) which rests against the rear side of the prism ( 78 ) and which is held stationary in recesses in the upper housing part and the lower housing part. 12. In-ground light according to claim 11, characterized in that the frame ( 86 ) is seated in a recess or groove ( 92 ) of the upper housing part ( 58 ) and has an outer projection ( 88 ) which engages in a slot ( 90 ) of the lower housing part ( 60 ). 13. In-ground light according to one of claims 6 to 12, characterized in that the housing lower part ( 60 ) forms the floor and the rear side and the housing upper part ( 58 ) forms the ceiling section, the front wall and the side walls of the housing ( 50 , 52 ). 14. In-ground light according to claim 13, characterized in that the front wall ( 66 ) and the rear wall ( 70 ) have a reinforced material accumulation in which threaded holes are formed. 15. In-ground light according to one of claims 5 to 14, characterized in that the prism ( 78 ) has a circumferential shoulder ( 80 ) between the front and the rear end and a complementary circumferential shoulder ( 82 ) is provided within the light passage opening ( 56 ), against which the shoulder ( 80 ) of the prism ( 78 ) rests.