WO2015063806A1

WO2015063806A1 - Public or street led lighting apparatus

Info

Publication number: WO2015063806A1
Application number: PCT/IT2014/000280
Authority: WO
Inventors: Marco POGGIALI
Original assignee: Enel Sole S.R.L.
Priority date: 2013-11-04
Filing date: 2014-10-29
Publication date: 2015-05-07
Also published as: ITRM20130604A1; AR098303A1

Abstract

Public or street LED lighting apparatus (1) comprising a printed circuit board (7), comprising an array of LEDs (6) adapted to emit an optical radiation, and a chassis (2) adapted to house within it the printed circuit board (7). The chassis (2) is made in such a way as to permit the operator to comfortably perform in situ a repair or maintenance operation if needed or resizing of the LED array (6). The chassis (2) makes it possible to effectively separate the LED array (6) from the remaining optical components of the lighting apparatus (1).

Description

Public or street LED lighting apparatus

FIELD OF THE INVENTION

[0001] The present invention relates to the technical field of LED lighting apparatuses and devices, in particular to the field of apparatuses and devices for public or street lighting.

STATE OF THE ART

[0002] In the field of public and street lighting, lighting appliances and apparatuses using semi-conductor light sources such as LEDs (Light Emitting Diodes) are becoming increasingly well established.

[0003] The use of LEDs makes it possible to produce lighting apparatuses characterised by a greater flexibility of use, greater energy efficiency and greater modularity.

[0004] LED lighting apparatuses generally comprise a plurality of LEDs, provided with relative optics and reflectors, appropriate heatsinks associated to said LEDs and appropriate power supply means adapted to provide the necessary power supply current to said plurality of LEDs.

[0005] LED lighting apparatuses have a more complex internal structure than the corresponding apparatuses using traditional incandescent light sources. The use of semi-conductor light sources and corresponding power supply means permits a high degree of miniaturisation which is reflected in construction solutions of extremely reduced dimensions compared to the past.

[ 0006] The small size of the LED lighting apparatuses entail optimisation requirements of the inner spaces which must house the necessary components, to ensure the necessary dissipation of the heat generated by electronic devices during operation and to leave the necessary space to perform maintenance and repairs.

[ 0007 ] In essence, the inner spaces of the aforesaid LED lighting apparatuses comprising electronic devices, must not only be such as to effectively house the electronic components required but must also be organised in an easily accessible manner to facilitate any maintenance on site, something which is particularly important in the case of public or street lighting apparatuses, usually situated in positions hard to reach for maintenance technicians.

[ 0008 ] he international patent application WO2013111171 describes a prior art LED street lighting apparatus provided with an outer chassis made in such a way as to permit the operator to comfortably perform in situ a repair or maintenance operation if needed.

[ 0009] The purpose of the present disclosure is to provide a public or street LED lighting apparatus comprising an array of LED sources, which makes repair operations of the functioning of the apparatus particularly rapid and economical in the case of failure of the LED array or in case in which a resizing of the LED array needs to be performed. [0010] Such purpose is achieved by a public or street LED lighting apparatus as generally defined in claim 1. Preferred embodiments of the aforesaid lighting apparatus are defined in the appended independent claims . [0011] The invention will be more clearly understood from the detailed description below of a particular embodiment made by way of a non-limiting example with reference to the appended drawings briefly described in the paragraph below. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 shows a perspective view from below of an embodiment of an LED public or street lighting apparatus comprising a chassis and a tubular shank for attaching the chassis to a support post, wherein the chassis comprises a base and a cover, wherein the base and the cover are shown in a closed operating configuration.

[0013] Figure 2 shows a plan view from below of the chassis in figure 1.

[0014] Figure 3 shows a plan view from above of the chassis in figure 1. [0015] Figure 4 shows a partial view in lateral cross- section of the chassis in figure 1 along the axis B-B of Figure 3.

[0016] Figure 5 shows a perspective view from above of the lighting apparatus in Figure 1, wherein the base and the cover of the chassis are shown in an open operating configuration .

[0017] Figure 6 shows a perspective view of an enlarged particular of the inside of the chassis of the lighting apparatus in Figure 1.

[0018] Figure 7 shows a perspective view of a further enlarged particular of the chassis of the lighting apparatus in Figure 1 wherein the base and the cover are shown in an open operating configuration. DETAILED DESCRIPTION

[0019] With reference to the appended drawings, the public or street LED lighting apparatus 1 (hereinafter referred to as "LED street lighting apparatus" without by so doing introducing any limitation) comprises a chassis 2 and a tubular shank 3 preferably detachably coupled to the chassis 2 and adapted to couple the chassis 2 to the support post, not shown in the figures, for example, placed at the edge of a road or urban area to be illuminated. [0020] The chassis 2 comprises a base 10 and a cover 20. Preferably, the base 10 comprises attachment elements to be detachably secured to the tubular shank 3. Such attachment elements for example comprise a system of toothed surfaces, openings and locking screws making it possible to selectively determine the orientation of the base 10 in relation to the tubular shank 3 in the attachment configuration of the aforesaid components.

[0021] The LED street lighting apparatus 1 comprises an array of LEDs 6, for example arranged on a rectangular or square matrix, mounted on a printed circuit board 7 for example mounted superficially on the printed circuit board 7. The LED array 6, and thus also the printed circuit board 7, are housed inside the chassis 2. In the installation configuration and during operation of the street lighting apparatus 1, the LEDs 6 are such as to direct the optical radiation emitted towards the road surface or towards the ground of an urban area to be illuminated.

[0022] According to a preferred embodiment, each of the LEDs is overlooked or covered by a respective lens of an array of refractive lenses. Preferably, such lenses are injection moulded lenses in polymethyl methacrylate (PMMA) .

[0023] According to one embodiment, the cover 20 of the chassis 2 is made of a thermally conductive material which preferably has a high thermal conductivity. More preferably, the cover 20 is made of aluminium, or aluminium alloy, and is for example made in one piece by die-casting.

[0024] Preferably, the base 10 of the chassis 2 is also made of a material with a high thermal conductivity and is preferably made of aluminium or aluminium alloy, and is for example made in one piece by die-casting.

[0025] Preferably, the cover 20 has a bulged shell shape and has an outer convex side and an opposite inner concave side. The printed circuit board 7 on which the LED array 6 is mounted is permanently attached to the inner concave surface of the cover 20. To such purpose, at least one thermally conductive protruding element 8 projects from the inner surface of the cover 20 towards the base 10 of the chassis 2 to define a support and attachment plane of the printed circuit board 7. The aforesaid at least one thermally conductive protruding element 8 is preferably made in one piece with the cover 20, in the same material as the latter, and being in contact with the printed circuit board 7 favours the extraction of heat therefrom developed during the operation of the LED array 6. The extracted heat may then be advantageously dissipated through said cover 20, which thus acts as a passive heatsink. Preferably the at least one protruding element 8 comprises a plurality of protruding elements 8 arranged according to a matrix format. Preferably, the protruding elements 8 are columns for example with a circular cross-section which protrude from the inner surface of the cover 20 and are interposed between the printed circuit board 7 and the inner side of the cover 20. Preferably, a thermally conductive coating, such as a phase change thermally conductive film ("thermal conductive pad") is applied to the side of the printed circuit board 7 facing the inner side of the cover 20. According to one embodiment, the aforesaid thermally conductive film comprises an aluminium film coated on both faces with a phase change compound, for example a graphite-based compound, adapted to melt with the heat during operation to decrease the thermal resistance at the contact interface between the printed circuit board 7 and the at least one protruding element 8 by decreasing the surface roughness of the contact interface.

[0026] Preferably, the printed circuit board 7 is attached to the cover 20 by means of one or more screws 9 which cross the board 7 and engage in internally threaded seats provided in the cover 20. In the example in Figure 4, in which a plurality of protruding elements 8 are provided in the form of columns, it is possible for some of these (indicated in the figure by reference numeral 8') to comprise within them the aforementioned threaded seats inside which the screws 9 are inserted. [0027] Preferably, the base 10 has a side external to the chassis 2 and an opposite side inside the chassis 2. The outer side preferably comprises a first externally convex or flat portion 10a and a second externally concave portion 10b rearward of the first externally convex or flat portion 10a.

[0028] The base 10 comprises an opening 11 and a screen 13 transparent to the optical radiation emitted by the LED array 6 and adapted to occlude the opening 11. Preferably, the transparent screen 13 is a sheet-shape and is made of extra-clear tempered glass. The transparent screen 13 is attached to the base 10 on the inner side of the base and in the closed position of the chassis 2 faces the printed circuit board 7 on which the LED array 6 is mounted. The transparent screen 13 preferably has a greater area than the area of the opening 11 and lies on a rim of the opening 11. Preferably, between the transparent screen 13 and the rim of the opening 11 an annular gasket 16 is interposed and clamped adapted to ensure a watertight seal, for example in order to ensure a degree of protection IP66.

[0029] he lighting apparatus 1 further comprises a reflector 15, for example made of plastic and having a reflective surface facing the opening 11 of the base 10. Such reflector 15 is attached to the base 10 and preferably comprises an upper opening 15a adapted to be crossed by the LED array 6 in the closed operating configuration of the chassis 2. According to a particularly advantageous embodiment, the reflector comprises a first part attached to the base 10 (shown in Figure 5) , and a second part (not shown in the figures) coupling to the first part, for example at the upper opening 15a, to extend the overall size of the reflector 15 so as to adapt the dimensions of the upper opening of the reflector 15 to the dimensions of the LED array 6. [0030] The reflector 15 preferably comprises two parallel or substantially parallel relatively longer sides and two parallel or substantially parallel relatively shorter sides.

[0031] Preferably, in the closed operating configuration of the chassis 2, the reflector 15 surrounds the LED array 6.

[0032] Preferably, as in the embodiment shown in figure 6, the longer sides have a greater and equal width to each other than the width of the shorter sides, such widths of the shorter sides may even be different from each other, as in the example shown.

[0033] According to a particularly preferred embodiment, the reflector 15 has an outer rim which lies on the transparent screen 13 which in turn lies on the annular gasket' 16 which in turn lies on a rim which delimits the opening 11 of the base 10. The reflector 15, the transparent screen 13 and the annular- gasket 16 are pressed against the base 10 by a plurality of clamping devices 18, preferably evenly distributed around the opening 11. For example, the clamping devices 18 comprise elastic fins 18a which press on the screen 15 and are tightened to the base 10 with screws 18b which traverse it to engage in corresponding internally threaded blind holes provided in the base 10.

[0034] The base 10 and cover 20 are coupled to each other by means of attachment elements 4, 14, 21, 24. For example, the attachment elements 4, 14, 21, 24 comprise a cylindrical hinge which allows the opening of the base 10 and of the cover 20 keeping them connected to each other. In the example shown in the figures the aforesaid cylindrical hinge comprises a pair of pins 4, each of which is adapted to engage in a first through opening made in the cover 20 and a corresponding threaded through or blind hole made in the base 10.

[0035] Preferably and without by so doing introducing any limitation, the base 10 and the cover 20 are hinged around a hinge-axis A-A (the dotted line in Figure 2) placed next to the tubular shank 3 so that the base 10 and the cover 20 can reciprocally rotate around said axis A-A like two valves of a bivalve mollusc to switch from the closing configuration of the chassis 2 (Figure 1) to the open configuration of the chassis 2 (Figure 5) and vice versa. During such rotation, the LED array 6 which is attached to the cover 20 is such as to rotate integrally with the cover 20 to distance itself from the screen 13 and vice versa. [ 0036] According to one embodiment, the aforesaid attachment elements further comprise locking elements 14, 21, 24 adapted to detachably lock the base 10 and the cover 20 to each other in the closed position shown in figure 1. Such locking elements comprise, for example, a pair of screws 24 (see figure 3) , for example, Allen screws, which crossing respective openings 21 of the cover 20 are inserted into respective threaded seats 14 provided in the base 10.

[ 0037 ] According to one embodiment, the attachment elements between the base 10 and the cover 20 comprise an articulated arm 31, 32, comprising a first portion 31 hinged to the base 10 and a second portion 32 hinged to the cover 20, the two portions 31, 32 being hinged to each other in an intermediate point of the articulated arm 31, 32. Preferably, at least one of the two portions 31, 32 is attached, in particular hinged, respectively to the base 10 or cover 20, by means of a bracket 33, for example L-shaped, sliding in relation to the base 10 or to the cover 20 respectively, so as to be translated between an operating engagement position and operating disengagement position. In such latter position, the bracket 33 can be uncoupled from the base 10 or from the cover 20 respectively.

[0038] In the example shown in Figure 6, the bracket 33 is provided for the attachment of the second portion 32 of the articulated arm 31 32, to an inner wall of the cover 20. The bracket 33 comprises at least one through hole 34 of a variable area adapted to be crossed by an attachment device with a variable cross-section 35, such as for example a screw 35 with a prominent head in relation to the stem of the screw 35, suitable to engage in a threaded hole provided in the cover 20. The through hole 34 with a variable area comprises a first portion of hole of a relatively smaller area, which cannot be axially crossed by the prominent head of the screw 35, and a second portion of the hole of a relatively greater area, which can be axially crossed by the prominent head of the screw 35. In the locking position the screw 35 crosses the first portion of the hole, the screw 35 is tightened and the screw head 35 tightens the bracket 33 against an inner wall of the cover 20 preventing it from sliding. By slightly loosening the screw 35 it is possible to slide the bracket 33 parallel to the cover 20 and to ensure that the prominent head of the screw 35 is in the second portion of the hole of a relatively greater area, so that it is possible to axially extract the bracket 33 by the passage of the prominent head of the screw 35 through the second portion of the hole of a relatively greater area. This way it is possible to detach the bracket 33 and therefore, the articulated arm 31, 32 from the cover 20 without extracting the screw 35 fully but simply loosening it. In the particular non- limiting example shown in figure 6, two through holes with a variable area 34 and two respective screws 35 for the attachment of the bracket 33 to an inner wall of the cover 20 are provided for.

[0039] Once the bracket 33 is detached, in the example from the cover 20, it is possible to remove or loosen the two pins 4 to detach the cover 20 from the base 10, for example to remove the cover 20 from the base 10. This way it is possible to safely remove the cover 20 from the base 10 in a configuration in which the base 10 is installed high up on a support post by means of the tubular shank 3.

[0040] According to one embodiment, the articulated arm 31, 32 comprises a fall-prevention safety device 36, 37, 38 adapted to prevent the inadvertent or accidental closure between the cover 20 and the base 10 for example by falling of the cover 20 onto the base 10 starting from the opening position, shown in figure 5. For example, the fall-prevention safety device 36, 37, 38 comprises a fin 36 provided on one of the first 31 or second portions 32 of the articulated arm, a hook-shaped tooth 36 on the other of the first 31 and second portions 32 of the articulated arm, and a hinge element with a slotted hole 38 which makes it possible not only to rotatably hinge the two portions 31, 32 of the articulated arm but which allows these to translate with each other by a stroke sufficient to enable the fin 36 to be able to slide in relation to the hook-shaped tooth 37 between an engagement position and a disengagement position. This way, starting from the position shown in Figures 5 and 6, the fin 36 is engaged in the hook- shaped tooth 37 and the two portions 31, 32 of the articulated arm cannot rotate with each other; to allow this rotation it is necessary to disengage the fin 36 from the hook-shaped tooth 37 for example by raising and rotating the cover 20 in the opening direction in relation to the base 10 so that the fin 35 reaches the position of disengagement.

[0041] The base 10 and the cover 20, in the closed position define at least one inner chamber 5 of the chassis 2 which houses the electronic, optical and electro-optical components of the street lighting apparatus 1 requiring proper segregation from atmospheric agents or generally from contact with water and or moisture. For example, the inner chamber 5 is laterally delimited by two confinement collars 12, 22 respectively provided in the base 10 and in the cover 20, between which a gasket (not shown in the figures) is interposed and tightened in the closed position of the chassis 2. For example, one of the two of confinement collars 12, 22 (in the example the collar 22 of the cover 20), is a is double-walled collar and houses within a cavity defined between the two walls an annular seal, for example in silicone rubber, while the other of the two collars (in the example the collar 21 of the base 10) is a single wall collar adapted to engage at least partially in the cavity of the double wall collar 22 to clamp and compress the annular seal. Preferably, in the closed position between the base 10 and the cover 20, the inner chamber 5 of the chassis 2 has a watertight seal with degree of protection IP66.

[0042] The inner chamber 5 preferably houses a plate 40 to which an electronic driver module 41 of the array of LEDs 6 comprised in the lighting apparatus 1 is attached. Preferably, a remote control module 42 comprised in the lighting apparatus 1 which allows the control and/or remote monitoring of the street lighting apparatus 1 is attached to the support plate 40. The layout of the support plate 40 allows it to perform in a simple way an electrical connection between the various electrical or electronic components attached to the plate 40 and to extract such components in a block together with the plate. [0043] According to one embodiment, the plate 40 is attached to the inner face of the base 10 in the inner chamber 5, by means of removable quick lock/release coupling elements, so that they can be quickly removed and/or replaced by an operator for example for repair and/or replacement. [0044] According to one embodiment, a connector 43 is attached to the plate 40 to which it is possible to attach one end of an electrical interconnection cable having an opposite end adapted to be connected via a connector to the printed circuit board 7, to connect the aforesaid printed circuit board 7 to the electronic components housed in the inner chamber 5, for example to the driver module 41 and to the remote control module 42.

[0045] According to one embodiment, the chassis 2 comprises at least a first 39 and a second 39' watertight cable clamp which permit the passage respectively of a first and a second cable through confinement walls of the inner chamber 5, firmly constrain the two cables to the aforesaid walls and, being provided with gaskets, prevent infiltrations of water in the inner chamber 5 for example ensuring a level of protection IP66 of the inner chamber 5. A non- limiting example of a watertight cable clamp is described in the patent application EP1944844. [0046] According to the embodiment shown in figure 5, the aforesaid watertight cable clamps 39, 39' are attached to one of the two confinement collars 12, 22 and preferably to the confinement collar 12 of the base 10.

[0047] In the aforesaid embodiment in which at least a first and a second 39 39' watertight cable clamp are provided for, the lighting apparatus 1 comprises:

- a first power supply cable (not shown in the figure) of the lighting apparatus 1, which crosses the first cable clamp 39 and which is adapted to provide a mains electric voltage for the power supply of the lighting apparatus 1; and

- a second cable, for supplying a device external to the chassis 2 or transporting data, crossing the second cable clamp 39', separate from the first cable and adapted to transmit a data signal or a power supply signal between the inside and the outside of the watertight inner chamber 5.

[0048] According to one embodiment, the second cable is an Ethernet network cable such as a PoE (Power over Ethernet) . Said Ethernet cable is such as to permit connection of the lighting apparatus 1 to an IP network.

[0049] According to one embodiment, the street lighting apparatus 1 comprises a data communication interface housed in the inner chamber 5 and the second cable is a data transport cable and is operatively connected to said data communication interface. Said data communication interface is for example an interface of the remote control module 42.

[0050] According to a further embodiment, the second cable is a unipolar or multipolar power supply cable.

[0051] According to a further embodiment, the second cable is connected to an external twilight sensor or any further remote device or external to the chassis 2, to which it delivers the power supply voltage needed for its operation.

[0052] According to a preferred embodiment, the chassis 2 comprises at least one through opening 50 adapted to be crossed by the first and / or second cable. The through opening 50 is facing a hollow inner section 53 of the tubular shank 3 and is made for example in the base 10 outside the inner chamber 5 and next to a shaped region 51 of the base 10 of the mechanical interface with the tubular shank 3. This way it is possible to make the first and/or the second cable pass through the inner hollow section 53 of the tubular shank 3.

[0053] Some applications may require that second cable be connected to an external device placed near the end of the support post distal from the post base, thus positioned near or in contact with the chassis 2 and outside this. For this reason a lateral through opening (not shown in the figures) may be provided in the side walls of the tubular shank 3 adapted to be crossed by the second cable. Alternatively or in addition, the base 10 or the cover 20 (or both) may be fitted on a peripheral rim of a recessed edge portion 54, for example having a bulb-shaped section, inside which it is possible to insert the second cable laterally in a condition in which the base 10 and the cover 20 are in the open configuration. Thanks to the provision of such recessed edge portion 54 it is possible after laterally inserting the cable inside it, to close the base 10 and the cover 20 together without the second cable hindering - or interfering with such closure.

[0054 ] Preferably, the recessed edge portion 54 is positioned next to the cable clamp 39' designed to crossed by the second cable. In a preferred embodiment, according to the figures, this recessed edge portion 54 is provided in the base 10.

[0055] It is to b noted that the provision of the recessed edge portion 54 (or of a lateral through- opening of the tubular shank 3) and the through opening 50 of the chassis, makes it possible to implement three different configurations for the control of any remote devices located on the support post of the lighting apparatus 1 or in its immediate vicinity (such as at the base of the post) .

[0056] In a first configuration, a transport data cable which comes from the base of the support post (for example in the case of systems in which data is travelling on an optic fibre backbone) , which passes inside the support post and which crosses the through opening 50 and the recessed edge portion 54 (or the lateral through-opening of the tubular shank 3), can come out of the lighting apparatus 1 to control a remote device placed on the support pole in the vicinity of the lighting apparatus 1.

[0057] In a second configuration, a data transport cable from the remote control module 42 located in the chamber 5, or a power supply cable coming from the connector 43 located in the inner chamber 5 can come out of the chassis 2 to control and/or power an external device through the cable clamp 39' and the recessed edge portion 54 (or lateral through-opening of the tubular shank 3) .

[0058] In a third configuration, a data transport cable coming from the remote control module 42 located in the chamber 5, through the cable clamp 39' and the through opening 50, can cross the support post to control external devices placed for example at the base of the support post.

[0059] Preferably, the lighting apparatus 1 comprises a sectioning device 19, 29 comprising two complementary sectioning elements respectively attached to the base 10 and to the cover 20 and arranged facing one another in the closed configuration of the chassis 2. [0060] Preferably, the sectioning device 19.29 is positioned in the vicinity of the cable clamp 39 adapted to be crossed by the first cable.

[0061] he sectioning element 19 attached to the base 10 comprises an input port and an output port. The input port is adapted to be connected to the conductors of the mains power supply cable coming from outside and the output port is adapted to be connected to conductors connecting the sectioning device 19,29 and the various electrical or electronic components attached to the plate 40 which require a power supply voltage. By providing male contact elements in the sectioning element 29 attached to the cover 20 and complementary female contact elements, each adapted to receive a 'corresponding male contact element in the closed configuration of the chassis 2, in the sectioning element 19 attached to the base 10, the sectioning device 19, 29 makes it possible to automatically power down the various electrical or electronic components attached to the plate 40 which require a power supply voltage when passing from a closed position of the base 10 and the cover 20 to an open position.

[0062] As is clear from the above description, the lighting apparatus 1 proposed makes it possible to fully achieve the intended purposes in terms of overcoming the drawbacks of the prior art, in fact, the structure of the street lighting apparatus 1 described above allows an operator to safely perform maintenance or repair operations, since the cover 20 to which the LED array 6 is attached can be easily removed in safety from the base 10 to be repaired or replaced in case of malfunction or failure of the LED array 6 attached to said cover. It is to be noted that the removal of the cover 20, as regards the optical part involves only the removal of the LED array 6, while the remaining part of the optical components, such as the transparent screen 13 and the reflector 15 remain constrained to the base 10.

[0063] It is to be noted that by means of the lighting appliance 1 according to the present description, a public lighting apparatus may be provided, such as for example a lamp-post for street lighting, comprising a lighting apparatus according to the present description and a support post to which such lighting apparatus is attached. It is to be noted that the present invention also relates to such a street lighting apparatus.

[0064] Without prejudice to the principle of the invention, the embodiments and details of construction may be widely varied in relation to the description and illustrated purely by way of non-limiting example, without thereby departing from the invention as defined in the appended claims.

Claims

1. Public or street LED lighting apparatus (1) comprising a printed circuit board (7), comprising an array of LEDs (6) adapted to emit an optical radiation, and a chassis (2) adapted to house within it the printed circuit board (7), wherein the chassis (2) comprises:

- a base (10) comprising an opening (11) adapted to be crossed by the emitted optical radiation; - a cover (20) made in a thermally conductive material, the printed circuit board (7) being attached to an inner side of the cover (20) facing towards the base (10) and in thermal contact with the cover (20) ;

- removable attachment elements (4, 14, 21, 24) between the base (10) and the cover (20), adapted to keep both the base (10) and the cover (20) coupled to each other in an operating closed configuration of the chassis (2) and to disengage from each other the base (10) and the cover (20) to remove the cover from the base; - a screen (13) transparent to the optical radiation (6) attached to the base to occlude the opening (11) and positioned facing the array of LEDs (6) in the operating closed configuration of the chassis (2);

- a reflector (15), attached to the base (10) on an inner side of the base (10) facing the cover (20), adapted to intercept portions of said optical radiation to convey them towards the transparent screen (13) .

2. Public or street LED lighting apparatus (1) according to claim 1 wherein: - the attachment element (4, 14, 21, 24) comprises a cylindrical hinge (4) adapted to permit relative rotation of the cover (20) in relation to the base (10) between an angular closed position, corresponding to said operating closed configuration of the chassis (2) , and an angular open position of the chassis (2) and vice versa; and

- the printed circuit board (7) is integral with the cover (20) in the relative rotation thereof in relation to the base ( 10 ) .

3. Public or street LED lighting apparatus (1) according to claim 2, wherein the attachment elements of the base (10) and the cover (20) comprise an articulated arm (31, 32), comprising a first portion (31) hinged to the base (10) and a second portion (32) hinged to the cover (20), the two portions (31, 32) being hinged to each other in an intermediate point of the articulated arm (31, 32) .

4. Public or street LED lighting apparatus (1) according to claims 2 or 3, wherein at least one of the two portions (31, 32) is attached respectively to the base (10) or to the cover (20), by means of a bracket (33) sliding in relation to the base (10) or to the cover (20) respectively so as to be able to be translated between an operating position of engagement and an operating position of disengagement, wherein in said disengagement position the bracket (33) may be disengaged from the base (10) or from the cover (20) respectively.

5. Public or street LED lighting apparatus (1) according to claims 3 or 4, wherein the articulated arm (31, 32) comprises a safety device to prevent falling (36, 37, 38) adapted to prevent an unwanted or accidental closure of the cover (20) and the base (10) by the falling of the cover (20) .

6. Public or street LED lighting apparatus (1) according to claim 1, wherein the reflector (15) comprises an upper opening (15a) adapted to be crossed by the array of LEDs (6) in the operating closed configuration of the chassis (2) .

7. Public or street LED lighting apparatus (1) according to claim 6, wherein the reflector (15) comprises a first part attached to the base (10) and a second part couplable to the first part to extend the overall dimension of the reflector (15) so as to adapt the dimensions of the upper opening of the reflector (15a) to the dimensions of the array of LEDs (6) .

8. Public or street LED lighting apparatus (1) according to claim 1, wherein the transparent screen (13) is attached to an inner side of the base (10) and has a greater area than the area of the opening (11) and rests on a rim of the opening (11) , wherein between the transparent screen (13) and the rim of the opening (11) an annular gasket (16) is positioned and clamped, wherein the reflector (15) has an outer rim which rests on the transparent screen (13) which in turn rests on the annular gasket (16) which in turn rests on the rim defining the opening (11), wherein the reflector (15), the transparent screen (13) and the annular gasket (16) are pressed against the base by a plurality of clamping devices ( 18 ) .

9. Public or street LED lighting apparatus (1) according to claim 1, wherein in the operating closed configuration of the chassis (2), a watertight inner chamber (5) is defined between the base (10) and the cover (20) adapted to house the printed circuit board (7) .

10. Public or street LED lighting apparatus (1) according to claim 1 wherein:

- the cover (20) has a bulged shell shape and has an outer convex side opposite said inner side of the cover (20) which is concave; - from the inner side of the cover (20) at least one thermally conductive projecting element (8) projects towards the base (10) adapted to define a support and attachment plane of the printed circuit board (7) .

11. Public or street LED lighting apparatus (1) according to claim 10, wherein the aforesaid at least one thermally conductive projecting element (8) is made integrally with the cover (20) , in the same material as the latter, and being in contact with the printed circuit board (7) favours the extraction therefrom of the heat developed during the functioning of the array of LEDs (6), said heat being dissipated through said cover (20), which thus also acts as a passive dissipator .

12. Public or street LED lighting apparatus (1) according to claims 10 or 11, wherein the projecting element (8) comprises a plurality of projecting elements (8) arranged according to a matrix pattern arrangement.

13. Public or street LED lighting apparatus (1) according to any of the claims 10-12, wherein a thermally conductive phase change film is applied to a side of the printed circuit board (7) facing the inner side of the cover (20) .

14. Public or street LED lighting apparatus (1) according to any of the previous claims, wherein the base (10) has a side external to the chassis (2) comprising a first externally convex or flat portion (10a) and a second externally concave portion (10b), rearward of the first externally convex or flat portion (10a).

15. Lamp-post for public or street lighting, comprising an LED lighting apparatus (1) according to any of the previous claims and a support post to which such lighting apparatus (1) is attached.