The present invention relates to a LED lighting device, more particularly a lamp holder for light sources with replaceable LEDs integral with a heat sink.

It is well known that use of lighting devices exploiting a LED as light source, increased considerably in recent years. The present trend to use this lighting technology is due to economic as well as performance grounds. To a better quality of light produced by a LED when compared to the traditional incandescent or fluorescent lamps, a considerably reduced energy consumption is added. However the clear advantages of the LED technology are accompanied by non negletable difficulties of application: just to mention the most important ones, the complexity and specificity of the control circuit for the LED source as well as the considerable heat produced by its operation, must be taken into account.

Document WO 2010/146509 A1 discloses a connector to connect a component to a heat sink, comprising a support for a light source, a LED light source, a connector for feeding said light source, wherein the heat sink has means for fixing it to a lamp, where the connection is achieved by a bajonet joint and the heat sink is not a load bearing structure of the device, and replacement of the LED light source requires disassembly of the printed circuit board.

Document WO 2010/108906 A1 discloses a device similar to the above discussed document, wherein the heat sink is again an element not being part of the device bearing structure and is not provided with means for fixing directly to a lamp but is only integrated in a LED module.

Document EP 2339230 A2 discloses a very complex LED lighting assembly that is not suitable to support a simple lamp and is not provided with a heat sink used as a bearing structure of the assembly.

The LED lamp holder according to the present invention is designed in order to avoid the above mentioned drawbacks of adaptability and heat generation, providing for a lamp holder that in a preferred embodiment is made integral with the heat sink, which in turn may be interfaced on one hand with the light source and on the other hand with any lamp.

The LED lamp holder of the present invention, as it will be described in detail hereinafter, lends itself to replace in the existing lamps, the traditional lamp holders, such as those for incandescent or bulb lamps or any other known type.

Thus the main object of the present invention is to provide a lamp holder for LED light sources, that may be used as alternative or substitution for the traditional lamp holders, either for new or existing lamps.

Another object of the present invention is to provide a lamp holder for LED light sources, wherein it may be possible to replace only the LED light source, either in case of failure of the existing one or in case of installing a new LED source with different lighting characteristics.

Finally an object of the present invention is to provide a lamp holder for LED light sources, wherein heat dissipation is efficiently achieved by a passive device.

These and other characteristics of the LED lamp holder of the present invention will be apparent by reading the following detailed description of a preferred embodiment to be taken together with the accompanying sheets of drawings, where equal or similar elements are identified with the same reference numerals, and in which:

• Fig. 1 is an exploded perspective view of the LED lamp holder according to the preferred embodiment of the present invention;
• Fig. 2 is a second exploded perspective view of the lamp holder of Fig. 1;
• Fig. 3 is an exploded perspective view of some components of the lamp holder of Fig. 1;
• Fig. 4 is a second exploded perspective view of the components of Fig. 3;
• Fig. 5 is a perspective view of the heat sink of the lamp holder of the preceding figures;
• Fig. 6 is a second perspective view of the heat sink of Fig. 5; and
• Fig. 7 is the support of the LED light source used in the lamp holder of the preceding figures.

With reference now to Figures 1 and 2, the lamp holder 100 of the present invention comprises a cylindrical heat sink 10, a support 20 for a LED light source 30, a lens 40 applicable to said support 20, and a connector 50 for feeding the LED source. Moreover in Fig. 1 and 2 two different systems of mounting the lamp holder to a generic lamp are shown: a threaded collar 60, being only part of a lamp, and a group of three tubular members 70 adopted for some types of lamps, such as a lamp shade.

The heat sink 10 is a cylindrical body of extruded aluminum, so as to obtain a set of winglets 12 radially extending outwards from its central cavity or through hole 14. At positions axially symmetrical to the longitudinal axis of said cavity, three winglets 12a have a greater thickness than the remaining winglets 12 and a preferably threaded bore 12b, in which a first end 72 of said brass tubes 70 is screwed. The through hole 14 too is internally threaded at both ends 14a and 14b. As shown in the drawings, the heat sink 10 approximately at its median portion has a flange 18 with the function of abutment for attachment elements to a lamp (not shown) such as collar 60. Moreover the flange divides the outer surface of the heat sink in a first portion 10a (facing the support 20 and the corresponding light source) and a second portion 10b. Portion 10a is advantageously threaded to allow connection with the collar 60 (or similar connection element with a lamp body) which is internally threaded.

In Figures 2-4 and 7 one can see at various degrees of detail, support 20 comprising a disc 22, on whose upper surface 22a there is a seat into which the light source or board SMD-LED 30 may be slidingly inserted; in said seat electric contacts are also fixed, made of C-bent metal plates: the upper side of the C-bend of each plate is in contact with a terminal of the SMD board, while the lower side is connected to a pin which, through suitable holes made in the seat, passes through the disc 22 body and comes out from the lower surface 22b of the disc. From said lower circular surface 22b of disc 20, two approximately circular surfaces 24 are extended and externally threaded for engaging the thread 14a of the heat sink 10. More particularly surfaces 24 are so dimensioned as to receive and hold by friction a connector 50, into which the above mentioned electric pins are inserted. Finally, from connector 50 a pair of feeding wires 52 extended to traverse the cavity 14 of the heat sink 10 and available for the connection of an external power source (not shown). Therefore in this way the electric circuit of the lamp holder is defined, allowing to feed the LED light source just like a traditional lamp holder for incandescent or bulb light sources.

At last, as shown in the preceding figures, a lens 40 consists of a ring 42 and a member 44 that may be transparent, opaque or anyway treated for a correct diffusion of the light emitted by the LED. Ring 42 is made integral with protrusions 46 diametrically opposed and so shaped as to snap engage the above described support disc 20.

From the detailed description of the lamp holder 100 according to a preferred embodiment of the present invention, it is to be pointed out that said lamp holder fully achieves the above indicated objects of adaptability to existing lamps as well as to lamps of novel conception, without needing any modification thereof. Even the problem of overheating the lamp holder is solved by adopting the passive heat sink 10 with great thermal exchange surface, thus avoiding adoption of noisy ventilation systems involving additional energy consumption. Besides adaptability one can see also a considerable ease of replacement of the light source, by removing the lens and simply sliding the board out from the support seat, said replacement being required not only in the event of failure but also in case of another LED with different lighting characteristics.

Finally it has to be pointed out that the constructional features of the lamp holder 100 according to the preferred embodiment of the present invention, may be modified or changed in alternative embodiments. For instance, all the systems of fixing or fastening the parts may be changed, more particularly other attachment or connection systems may be adopted instead of threads. In a similar way, the forms and dimensions of the cooling winglets of the heat sink may be changed, merely by choosing different extrusion dies for the aluminum body 10. These and other variations to the preferred embodiment of the lamp holder of the present invention are however falling within the scope of protection as defined in the appended claims.