WO2024218716A1

WO2024218716A1 - Modular lighting element structure for an led light fitting

Info

Publication number: WO2024218716A1
Application number: PCT/IB2024/053806
Authority: WO
Inventors: Antonio Di Gangi
Original assignee: Antonio Di Gangi
Priority date: 2023-04-18
Filing date: 2024-04-18
Publication date: 2024-10-24

Abstract

In a modular structure (100) of a lighting element for an LED light fitting, a heat sink device comprises a fixed heat sink body (40), integral with the light fitting, and a movable heat sink body (20), frontally bearing an LED device (10), said heat sink bodies (20, 40) have respective fixed (45) and movable (25) central portions with respective front (41) and rear (29) heat exchange faces, an electrical connection means (50) is provided between the fixed body (40) and the movable body (20) including respective pairs of fixed (9) and movable (5) contacting elements, a spring-loaded (39) mechanical connection means (30) for pressing the front (41) and rear (29) faces of the heat sink bodies (20, 40) against each other by a predetermined compression force (F). The heat sink bodies (40, 20) comprise respective fixed (44) and movable (24) heat sink peripheral portions around respective central portions (45, 25), wherein said movable contact elements (5) and said fixed contact elements (9) are housed within said movable and fixed heat sink bodies (20, 40) with interposition of respective fixed and movable insulating elements (7, 8), wherein said movable and fixed peripheral heat sink portions (24, 44) are configured to be brought to a heat exchange contact with each other and, simultaneously, to establish an electrical contact between said movable and fixed contact elements (5,9) when the mechanical connecting means (30) press said movable and fixed heat sink bodies (20, 40) to each other.

Description

TITLE

MODULAR LIGHTING ELEMENT STRUCTURE FOR AN LED LIGHT FITTING

DESCRIPTION

Scope of the invention

[0001] The present invention relates to the field of lighting technology and, more in particular, it relates to a modular lighting element structure for a light fitting including power LEDs.

Front technology - Technical problems

[0002] LED light fittings are known in which an LED device, comprising one or more LED emitters that have the form of a board arranged on a mounting base or 'socket'. The LED device is in turn mounted on a body, usually made of aluminium, whose main purpose is to dissipate the heat generated by the LED emitter(s). In fact, as it is well known, one of the problems with LED light fittings is cooling, since, as the temperature rises, the performance of electronic components of the LED devices deteriorates and, if an accurate temperature control is missing, those components can “'bum out” in a short time.

[0003] Also known is the fast development of LED technology, which provides LED emitters and devices with ever-increasing efficiency and innovative features. Due to this trend, many users fell the need for even more performant and up-to-date light fittings.

[0004] However, the conventional LED light fittings include monolithic, often bulky and expensive heat sink bodies, in which finned surfaces are provided to cope with the most severe applications.

[0005] In these conditions, in order to conform a LED lighting system to the currently available technique, or even to adapt it to changing lighting requirements, such as lighting power or some light features, etc., it is necessary to completely replace the light fittings, which is very expensive. Even if the the replacement of LED emitters and devices ids technically possible, it requires special care and, in any case, expensive specialised labour is necessary. [0006] Conventional connection means between LED devices and heat sink bodies, such as screw connections, have the disadvantage of not providing a reproducible tightening, unless expensive and hard-to-use devices such as torque spanners are used. Moreover, the difficult screws tightening control can also lead to over-tightening between the connected parts, which can cause permanent deformations of the contacting surfaces. Even if these deformations are very small, they can make an optimal contact hard to obtain, i.e. contact conditions between the surface microstructures tight enough to maximise the interface heat transfer.

[0007] Accordingly, a need is felt for a modular LED lighting element structure that allows critical components to be disassembled, replaced and mounted on existing equipment, while providing a heat exchange capacity at least comparable to the performances of conventional non-removable devices.

[0008] US2011261572 describes a lamp device including a flat light source fixed to a heat-radiating body. A pressing body elastically presses the movable heat-radiating body in a contact direction onto a fixed heat sink body. An electrical connection is provided by electrical connectors engaging slots formed on an insulating peripheral body. The heat exchange between the movable and fixed part occurs therefore at a central zone, while the electrical connection is made at a peripheral zone.

[0009] US2013021808A1 also describes lamp devices each including a flat light source fixed to a heat-radiating body that is movably connected to a heat sink body. The electrical connections are made at a central portion, while the heat exchange occurs at a peripheral portion.

[0010] US20213106451 describes lamp devices including a central light source movably attached to a radial heat sink body.

[0011] The above light fittings allow both a simplified detachment of the light source from a support member and heat dissipation through the support member. However, they have poor dissipation performances. Moreover, they are not designed to allow a quick replacement of the light source by unskilled workers or directly by the users.

Summary of the invention

[0012] It is therefore an object of the present invention to provide such a modular structure that can dissipate the heat generated by the LED(s) during operation better than the prior art devices that allow the lighting body to be easily disassembled. [0013] It is also an object of the invention to provide such a modular lighting element structure for an LED light fitting that has a high illumination efficiency and that can be easily disassembled by a user, without using special tools and instruments, and/or without resorting to very skilled labour.

[0014] Moreover, it is an object of the invention to provide such a structure that allows reproducible tightening conditions between a fixed part thereof, i.e. a part that is integral to the light fitting, and a movable LED module, as well as reproducible heat exchange condition between the above-mentioned parts.

[0015] The above-mentioned objects are achieved by a modular lighting element structure for an LED light fitting as defined in claim 1. Advantageous embodiments of this modular structure are defined in the dependent claims.

[0016] According to the invention, such a modular lighting element structure comprises:

- an LED device;

- a heat sink device;

- an electrical connection means arranged to electrically connect the LED device to an electrical power source; wherein the heat sink device includes a fixed heat sink body having a fixed central portion with a front heat exchange face; a movable heat sink body having a movable central portion with a rear heat exchange face, the LED device mounted integrally to the movable heat sink body; a mechanical connection means between the fixed heat sink body and the movable heat sink body, configured in such a way that the movable heat sink body and the LED device form a LED module removable from the fixed heat sink body; wherein the removable electrical connection means between the LED device and the power source comprise two fixed contact elements and two movable contact elements on the fixed heat sink body and the movable heat sink body, respectively, wherein the mechanical connection means comprises a spring element arranged to press the rear heat exchange face of the movable heat sink body and the front heat exchange face of the fixed heat sink body against each other by a mutual compression force.

[0017] Still according to the invention,

- the movable heat sink body comprises a movable heat sink peripheral portion surrounding the movable central portion, wherein the movable contact elements of the movable heat sink body lie on the movable heat sink peripheral portion surrounded by movable insulating elements, and

- the fixed heat sink body comprises a fixed heat sink peripheral portion surrounding the fixed central portion, wherein the fixed contact elements of the fixed heat sink body lie on the fixed heat sink peripheral portion surrounded by fixed insulating elements;

- the movable heat sink peripheral portion and the fixed heat sink peripheral portion are configured to come into a heat sink contact with each other and, at the same time, to cause an electrical contact between the movable and fixed contact elements when the mechanical connection means causes the rear heat exchange face of the movable heat sink body and the front heat exchange face of the fixed heat sink body to be pressed against each other by the aforementioned mutual compression force.

[0018] This way, the heat dissipation function is performed by both the central portion and the peripheral portion, so as to maximise the heat transfer. At the same time, the movable heat sink body, together with the LED fixture, which is the most valuable component of the entire fixture, forms an LED module that can be easily removed from the remaining fixed part of the fixture itself, and can be therefore easily replaced by another LED module that is mechanically and electrically identical to the first one, but has different optical and/or aesthetic characteristics, according to the user's needs. The LED module, comprising the LED fixture and the movable heat sink body, forms a structure with the fixed heat sink body in which the movable and fixed heat sink bodies are thermally in contact with each other through the maximum available contact surface area, and in which the movable and fixed electrical contact elements are in electrical contact with each other through the minimum necessary contact surface area, so as to maximise heat exchange while ensuring a safe electrical contact.

[0019] In comparison to US2011261572, which has a peripheral insulating zone, to US2013021808A1, which has a central insulating zone, and to US20213106451, which exchanges heat only in a radial direction, the modular lighting element structure according to the invention allows maximum heat dissipation and at the same time enables by the user itself to easily remove and replace the movable heat sink body, along with the LED device, without resorting to very skilled labour. Moreover, the mechanical connection means between the fixed heat sink body and the movable heat sink body assists the heat transfer regardless they are arranged centrally or peripherally, since both the fixed/movable central portions and the fixed/movable peripheral portions have enhanced heat dissipation properties.

[0020] In other words, the invention provides a modular lighting element in which the key-component, i.e. the LED module, can be easily replaced by a non-expert user, for instance, in order to change the LED light temperature, i.e. the colour aesthetic properties, without resorting to either special devices and tools, or qualified labour: At the same time the above key-component is able to dissipate the heat generated by the LEDs better than the above-mentioned prior art removable LED light fittings, and provides a heat dissipation capacity that is substantially comparable to the heat dissipation capacity of the known one-piece LED light fittings, including non-removable heat sink bodies.

[0021] Moreover, the mechanical connection means structure stands out for a greater reliability than the conventional means connecting the fixed and movable heat sink bodies, which can become loose due to thermal expansion.

[0022] In order to maximise the heat transfer between the movable heat sink module and the fixed heat sink module, a thermal interface layer is advantageously interposed between the contact faces of the two bodies in order to improve the heat dissipation, by suppressing the effects of the unavoidable surface ridges of the two contact faces. The thermal interface layer can be easily selected by a skilled person among the commercially available materials, which can have the form of a film or of a paste, forming a thickness in the order of tenths of a millimetre.

[0023] An LED device is any device configured to house one or more LEDs and to emit light in a predetermined direction. In particular, the LED device may comprise a mounting base and an LED emitter that has normally the form of a board and is mounted on the mounting base. The mounting base and the module can in many cases be easily selected by the skilled person among the commercially available materials taking into account any specific lighting purpose.

[0024] In the foregoing disclosure of the invention, and in the following description, such words as "front", "rear", "forward" or "backward" refer to the light emission (front/forward) by the LED device.

[0025] In a first embodiment, the mechanical connection means comprises a shank or stem connected to the fixed heat sink body and arranged through a through hole of the movable heat sink body, its own end portion protruding from a front face of the movable heat sink body, and further comprises, on the same end portion, an actuation head, that may have the form of a plate, a disc or a wheel, wherein the spring element is a compression spring interposed between the front face of the movable heat sink body and a rear face of the actuation head that faces the above front face, such that, by rotating the actuation head in a predetermined rotation direction, in one step of assembling a lighting element according to this structure, the actuation head approaches the fixed heat sink body by progressively compressing the compression spring, and the shank pulls the movable heat sink body and the fixed heat sink body against each other by the mutual above-mentioned compression force. Heat transfer occurs through a maximum surface area, as mentioned above, between both the fixed and movable central portions, and the fixed and movable peripheral portions.

[0026] In particular, a connection can be provided between the shank and the fixed heat sink body, said connection selected between:

- an integral connection, e.g. a welded connection or a stud connection, or the shank and the fixed heat sink body are formed in one piece, and the end portion and the actuation head are threaded and are screw-engaged in each other;

- a threaded manoeuvre connection, wherein the shank engages a threaded hole of the fixed heat sink body, while the end portion is integral with the actuation head.

[0027] In other words, in a first variant of the first embodiment, the shank is integral with the fixed heat sink body, the end portion and the actuation head are threaded and screw-engaged with each other. As an alternative, in a second variant of the first embodiment, the shank is screw-engaged in a threaded hole of the fixed heat sink body, and the end portion is integral with the actuation head.

[0028] In a second embodiment, the mechanical connection means comprises an elongated actuation head which is screw-engaged in a threaded through hole of the movable heat sink body, wherein the elongated actuation head is connected to the spring element in such a way that, by rotating the elongated actuation head in a predetermined rotation direction, the spring element is pulled towards the elongated actuation head so that the movable heat sink body and the fixed heat sink body are pressed against each other by the mutual above-mentioned compression force.

[0029] In particular, the spring element is selected from the group comprised of:

- a tension spring integrally connected to the fixed heat sink body and the extended actuation head; - a compression spring arranged between a back wall of the fixed heat sink body and an enlarged end portion of a shank extending from the elongated actuation head and passing through a through hole of the fixed heat sink body, so that the compression spring is squeezed between the enlarged end portion and the back wall of the fixed heat sink body.

[0030] In other words, in a first variant of the second embodiment, the spring element is a tension spring integrally connected to the fixed heat sink body and the elongated actuation head. As an alternative, in a second variant of the second embodiment, the elongated actuation head includes a shank that is arranged within a through hole of the fixed heat sink body, and has an end portion configured to compress the spring element against a back wall of the fixed heat sink body.

[0031] In further variants of the embodiments described above, there is a strokelimiting element configured to limit the stroke of the actuation head so that the mutual compression force between the movable and fixed heat sink bodies does not exceed a predetermined value. In particular, the actuation head of the first embodiment may comprise protrusions that face the front face of the body and are long enough to prevent further screwing of the actuation head onto the fixed shank, in the first variant, and of the shank into the fixed heat sink body, in the second variant. In the second variant, as an alternative, a stop element can be provided at the front face of the movable heat sink body, for instance, the top element has the form of a restricted portion of the through hole of the movable heat sink body.

[0032] The stroke-limiting element makes it possible to avoid over-tightening between the fixed and movable heat sink bodies, which would lead to permanent deformation of the respective surfaces in contact to each other, in which case a suitable heat exchange could not be possible after a subsequent reassembly.

[0033] In a third embodiment, the mechanical connection means comprises a cam profile configured to actuate the spring element when the movable heat sink body is caused to translate or rotate with respect to the fixed heat sink body, once the rear face of the movable heat sink body has been brought next to the front face of the fixed heat sink body.

[0034] This embodiment has the remarkable advantage of allowing the LED module, i.e. the movable heat sink body carrying the LED device, to be assembled and disassembled by simply rotating the module, without using any conventional tool such as a screwdriver, and without resorting the assistance of qualified personnel. This way, the user can modify a pre-existing LED light fitting to attain specific new performances requiring the replacement of the LED device, for instance, to change the colour, hue, intensity and other properties of the light, or to update a lighting system to the power LED state of the art.

[0035] In a first variant of the third embodiment, the cam profile is formed on the fixed heat sink body, and the spring element is connected to an actuation head which protrudes from the movable heat sink body such that, by the above-mentioned translation or rotation movement, the cam profile pulls the actuation head towards the movable heat sink body by tensioning the spring element.

[0036] In a second variant of the third embodiment, as an alternative to the last one, the cam profile is formed on the movable heat sink body, and the spring element is connected to an actuation head which protrudes from the fixed heat sink body such that, by the above-mentioned translation or rotation movement, the cam profile pulls the actuation head towards the fixed heat sink body by tensioning the spring element.

[0037] In the latter variant, as described below, the abutment head allowing the spring element to be compressed protrudes rearwards with respect to the fixed heat sink body, so it is hidden even when frontally looking at the LED light fitting, which is a favourable aesthetic effect.

[0038] The cam profile may be formed directly on the fixed heat sink body or the movable heat sink body, in particular, at the front or rear surface thereof, respectively, or it may be formed on an external body that is welded or mounted to the fixed heat sink body or to the movable heat sink body, in particular, it may be reversibly mounted to the front surface of the fixed heat sink body or to the rear surface of movable heat sink body. [0039] This way, the construction of the cam profile is simplified, since no inner body surfaces has to be machined in this case. Moreover, the material of the outer body, and thus of the cam profile, can be specifically chosen to resist wear when the actuation head slides on the cam profile surface. To this purpose, the body on which the cam profile is formed can be made of a low-friction material, such as brass, while the movable and fixed heat sink bodies are preferably made of aluminium, or in any excellent heat conductor.

[0040] More specifically, the actuation head comprises a shank passing through a through hole of the fixed heat sink body, and the shank has an end portion configured to press the spring element against a back wall of the fixed heat sink body. [0041] Preferably, as a feature that can common to all the embodiments described so far, a mechanical connection means is formed on the movable heat sink peripheral portion and the fixed heat sink peripheral portion.

[0042] In particular, the mechanical connection means is angularly offset, preferably by about 90°, with respect to the fixed and movable contact elements.

[0043] Advantageously, each of the movable contact elements of the electrical connection means comprises a conducting element enclosed in a rigid insulating sheath, wherein a radial protrusion extends from an outer surface of the insulating sheath, and in which a compression spring is butt-mounted between the radial protrusion and the movable heat sink body. In this way, the contact of each movable contact element with the corresponding fixed contact element of the electrical connection means is ensured, in particular, even if thermal expansion or contraction occurs, for example, caused by a LED light fitting temperature change.

[0044] In an embodiment, the modular structure also includes an additional module selected from the group comprised of:

- a lens with a light aperture angle set between 2° and 60°;

- an optical filter;

- an anti-glare spacer element;

- a combination of the above, wherein the further module and the LED module comprise respective mutual connection means, forming for instance a bayonet interlocking device, adapted to be be reversibly connected to each other by consecutive mutual-approach and rotation movements.

Brief description of the drawings

[0045] The invention will be illustrated below with a description of certain embodiments, by way of example and not limitation, with reference to the accompanying drawings, in which

- Figs. 1 and 2 are diagrammatic longitudinal cross-section view views of lighting elements having the modular structure of the invention, according to two variants of a first embodiment of the invention, in which the mechanical connection means between the movable heat sink body and the fixed heat sink body comprises a shank protruding from the latter and an actuation head arranged to compress a compression spring; Figs. 3 and 4 are diagrammatic longitudinal cross-section views of lighting elements according to two variants of a second embodiment of the invention, in which the mechanical connection means comprises an elongated actuation head that is screw-engaged in a threaded through hole of the movable heat sink body, and is arranged to compress or pull a compression or tension spring;

Figs. 5 and 6 are detail longitudinal section views of a lighting element as in Figs. 1 or 2 and Fig. 3 or 4, respectively, diagrammatic ally showing stroke-limiting elements of the actuation head to limit the mutual compression force between the movable and fixed heat sink bodies;

Fig. 7 is a diagrammatic cross section view of an LED device, suitable for the devices according to the embodiments of the invention, and to the respective variants thereof, as shown in Figs. 1-4;

Figs. 8 and 9 are diagrammatic exploded perspective views of lighting elements according to two variants of a third embodiment of the invention, in which the mechanical connection means between the fixed heat sink body and the movable heat sink body comprise a cam profile arranged to actuate a spring element when the movable heat sink body is caused to rotate with respect to the fixed heat sink body, in particular

- in the lighting element of Fig. 8, the cam profile is formed on the fixed heat sink body, while

- In the lighting element of Fig. 9, the cam profile is formed on the movable heat sink body;

Figs. 10 and 11 are elevation and perspective cross-sectional views, respectively, of an LED module of the modular structure according to a variant of the structure of Fig. 9, in which two cam profiles are carved in a cam ring that is manufactured separately and then mounted to the heat sink body;

Fig. 12 is a perspective view of the cam ring of Fig. 11;

Figs. 13 and 14 are diagrammatic cross-sectional view, along axial cross planes orthogonal to each other, of possible embodiments of the invention, in which the with the heat dissipation flow is shown;

Fig. 15 is an exploded perspective view of the lighting element of Figs. 10-12, in which the mechanical connection means further comprise a shank arranged in a through hole drilled in the fixed heat sink body, and in which the shank provides an abutment end portion configured to compress the spring element against a back wall of the fixed heat sink body;

- Figs. 16 and 17 are partially exploded perspective views of the lighting element of Fig. 15, in which the LED module is shown in a mounted condition;

- Fig. 18 is a perspective view of a fixed heat sink body of a lighting element according to a further variant of the embodiment shown in Figs. 15-16, in which a finned side surface is provided to assist dissipation of the heat generated by the LED fixture;

- Fig. 19 is a perspective cross-sectional view of an LED module of the modular structure according to the variant of the third embodiment of Fig. 10, in which a thermal interface layer is interposed between the contacting surfaces of the movable and fixed heat sink bodies;

- Figs. 20 and 21 are exploded and mounted perspective views, respectively, of a first indoor LED light fitting including the lighting element of Figs. 10-17;

- Figs. 22 and 23 are diagrammatic exploded and mounted perspective views, respectively, of a second indoor LED light fitting comprising the lighting element of Figs. 10-17;

- Figs. 24 and 26 are diagrammatic exploded and mounted perspective views, respectively, of a third indoor LED light fitting comprising the lighting element of Figs. 10-17;

- Figs. 26 and 27 are exploded and mounted perspective views, respectively, of a fourth indoor LED light fitting comprising the lighting element of Figs. 10-17;

- Figs. 28 and 29 are diagrammatic exploded perspective views of fifth and sixth outdoor LED light fittings.

Description of embodiments of the invention

[0046] With reference to Figs. 1-9, a modular lighting element structure 100 for an LED light fitting 110 is described, according to the invention.

[0047] Modular lighting element structure 100 comprises an LED device 10, i.e., a device that is configured to house one LED or a plurality of LEDs and is arranged to emit light in a predetermined direction, hereafter referred to as a forward direction. Specifically, as diagrammatically shown in Fig. 7, in a conventional arrangement, LED device 10 comprises an LED emitter 1 mounted on a mounting base or socket 2. Both components can be readily selected by a skilled person among the commercially available materials to achieve a particular lighting purpose.

[0048] In order to accommodate LED device 10 and dissipate the heat generated by it, so as to keep the temperature thereof below a safe value for its medium- long term stability, lighting element 100 includes a mounting and heat-sink device 20-40.

[0049] According to the invention, the mounting and heat-sink device comprises a fixed part 40, integral with the rest of LED light fitting 110, and a movable part 20 which can be detached from fixed part 40. LED device 10 is integrally mounted on a front face 21 of the movable part. In other words, movable part 20 and LED device 10 form an LED module 80 that can be detached from fixed part 40, which is integral with the system to which the LED light fitting belongs.

[0050] Fixed part 40 and movable part 20 comprise respective fixed central portions 41a and movable central portions 25 having a front heat exchange face 41 and a rear heat exchange face 29, respectively. In fact, in the exemplary embodiments shown, fixed portion 40 and movable portion 20 of the mounting and heat-sink device are mounted to each other by juxtaposing and tightening together rear heat exchange face 29 of movable portion 20 and front heat exchange face 41 of fixed portion 40, the contact interface between the rear and front mutual heat exchange faces 29,41 contributing together with peripheral portions 24,44 to the dissipation of the heat generated during operation of the LED light fitting.

[0051] In order to tighten/separate fixed part 40 and movable part 20, i.e. between respective rear and front heat exchange faces 29 and 41, i.e. in order to mount/remove LED module 80 from fixed body 40, a mechanical connection means 30 is provided, which is described More in detail below and is conceived to assist/maximise the heat flow through the heat-sink device.

[0052] Advantageously, as shown in Fig. 4, as well as in Figs. 9 and 19, a thermal interface layer 27, normally a few tenths of a mm thick, is arranged between rear face 29 of movable heat sink body 20 and front face 41 of fixed heat sink body 40. The thermal interface layer allows to enhance the heat exchange between movable heat sink body 20 and fixed heat sink body 40 by filling the air pockets that remain interposed between respective contacting faces 29 and 41, and are an effect of the unavoidable surface processing ridges remaining on faces 29,41. The thermal interface material may be in the form of a film or paste, and can be easily selected by a skilled person from commercially available materials. [0053] In the following, two fixed and movable parts 40,20 are referred to as fixed heat sink body 40 and the movable heat sink body 20, respectively.

[0054] Mechanical connection means 30 to connect fixed heat sink body 40 and movable heat sink body 20 comprise a spring element 39 arranged to press movable heat sink body 20 and fixed heat sink body 40 against each other at pective rear heat exchange faces 29 and front heat sink faces 21, by a mutual compression force F, so as to optimise the connection and heat transfer conditions at the interface 29-41 between movable heat sink body 20 and fixed heat sink body 40.

[0055] Fixed part 40 and movable part 20 also comprise respective fixed and movable heat sink peripheral portions 44,24 surrounding fixed and movable central portions 45 and 25, respectively.

[0056] In order to electrically power LED device 10, an electrical connection means 50 is provided for electrical connection to a power supply source, the electrical connection means comprising conducting elements 9, 5 arranged through corresponding fixed and movable peripheral portions 44, 24 and insulated therefrom by fixed and movable insulating elements 7,8, with respect to front heat exchange face 41 and rear heat exchange face 29 of fixed heat sink body 40 and of movable heat sink body 20, respectively, of LED module 80.

[0057] More specifically, electrical connection means 50 comprises two fixed contact elements 9 on fixed heat sink body 40, surrounded by fixed insulating elements 7 so as to be insulated from fixed heat sink body 40, and two movable contact elements 5 on movable heat sink body 20, surrounded by movable insulating elements 8 so as to be insulated from movable heat sink body 20, as described more in detail with reference to Fig. 15.

[0058] Mechanical connection means 30 and electrical connection means 50 are configured in such a way that, by tightening fixed heat sink body 40 and movable heat sink body 20 brings each movable contact element 5 into contact with a respective fixed contact element 9, emerging from fixed and movable peripheral portions 44,24 respectively, when the tightening operation comes to an end.

[0059] So far, features common to various possible embodiments of the invention have been described. In the following, some of these embodiments and respective variants are described. These embodiments and variants differ from each other, in particular, in the structure and other features of mechanical connection means 30 connecting fixed heat sink body 40 and movable heat sink body 20.

[0060] In a first embodiment, diagrammatically shown in Figs. 1 and 2, mechanical connection means 30 comprises an elongated element 31, referred to as a shank or a stem, that is connected to fixed heat sink body 40. In particular, the elongated element protrudes from front face 41 of fixed heat sink body 40 in the direction of a longitudinal axis a of lighting element 100. Movable heat sink body 20 provides a through hole 22 through which shank 31 is arranged. The shank protrudes with its own end portion 31a from front face 21 of movable heat sink body 20. At end portion 31a there is provided an actuation head 34a, for example in the form of a plate, a disc or a wheel or handwheel, which has a rear face 34d facing front face 21 of movable heat sink body 20. Spring element 39, in the form of a compression spring preferably made of stainless steel, is interposed between front face 21 of movable heat sink body 20 and rear face 34d of actuation head 34a.

[0061] This way, by rotating actuation head 34a in a predetermined rotation direction, in a step of mounting lighting element 100, actuation head 34a approaches fixed heat sink body 40 and progressively compresses compression spring 39, which applies a force F to the parts that are respectively connected to its end portions, i.e. to movable heat sink body 20, which is in contact with the spring directly or through a washer 21a, and to fixed heat sink body 40, which is in contact with the spring through shank 31, whereby fixed heat sink body 40 and movable heat sink body 20 are pressed against each other by this force F, which is therefore a mutual compression force.

[0062] In particular, mechanical connection means 30 comprises a plurality of assemblies each formed by shank 31, actuation head 34a and spring element 39, said assemblies preferably arranged along axes b that are arranged at a same angle from one another around longitudinal axis a of lighting element 100, in particular, two such assemblies are arranged along axes diametrically opposite to each other with respect to longitudinal axis a.

[0063] Two variants of the first embodiment are now described, which differ from each other in the way shank 31 is connected to actuation head 34a and to fixed heat sink body 40.

[0064] Referring to Fig. 1, in a first variant of the first embodiment, shank 31 is integral with fixed heat sink body 40. For instance, shank 31 may be connected to fixed heat sink body 40 by a stud connection, or by welding, or shank 31 and fixed heat sink body 40 may be formed as a single piece. End portion 31a of shank 31 is threaded, and actuation head 34a has a central threaded hole, and is screw-engaged with end portion 31a. This way, by rotating actuation head 34a, the latter slides along end portion 31a of shank 31 and compresses compression spring 39 more or less, causing compression force F exerted between fixed heat sink body 40 and movable heat sink body 20 to change.

[0065] Referring to Fig. 2, in a second variant of the first embodiment, shank 31 is slidingly screw-engaged within a threaded hole of fixed heat sink body 40, while end portion 31a is integral with actuation head 34a. Thus, by rotating actuation head 34a, shank 31 slides within the threaded hole of fixed heat sink body 40. Therefore, actuation head 34a moves forwards or backwards, away from or towards movable heat sink body 20, and compresses compression spring 39 more or less, causing compression force F exerted between the two fixed heat sink body 40 and movable heat sink body 20 to change.

[0066] Fig. 5 shows a common variant of the first embodiment, in which actuation head 34a has one or more protrusions 34f of a predetermined length on the side facing movable heat sink body 20, so as to abut against front face 21 of movable heat sink body 20 when spring 39 is compressed to such an extent to express a compression force having a predetermined maximum value F*. Therefore, protrusion or protrusions 34f act(s) as stroke-limiting element(s), and enable(s) mutual compression force F exerted between fixed heat sink body 40 and movable heat sink body 20 not to exceed such limit value F*, which is selected in such a way to prevent rear surface 29 and front surface 41 of movable heat sink body 20 and of fixed heat sink body 40, respectively, in particular the latter, from permanent deformation caused by the of mutual tightening.

[0067] In a second embodiment, diagrammatically shown in Figs. 3 and 4, mechanical connection means 30 comprises an elongated actuation head 34a that is screw- engaged in a threaded through hole 22 of movable heat sink body 20, preferably parallel to longitudinal axis a of lighting element 100. Elongated actuation head 34a is connected to spring element 39, for instance, in one of the ways described below. Elongated actuation head 34a has a tool-connection portion 34g for a tool, not shown, for example a polygonal section seat for engagement with an Allen key. In this way, by rotating elongated actuation head 34a in a predetermined rotation direction, in an step of assembling lighting element 100, spring element 39 can be pulled towards elongated actuation head 34a, whereby movable heat sink body 20 and fixed heat sink body 40 are more or less pressed against each other by mutual compression force F exerted by spring 39 responsive to the action exerted by elongated actuation head 34a.

[0068] Through hole 22 has a thread ending at a certain distance from rear face 29 of movable heat sink body 20, said distance long enough to allow elongated actuation head 34a to be fully accommodated in the rear unthreaded area of through hole 22 itself. This way, upon disassembling movable heat sink body 20, the latter can be moved away from fixed heat sink body 40, while elongated actuation head 34a protrudes cantilevered from front face 41 of fixed heat sink body 40.

[0069] In particular, mechanical connection means 30 comprises a plurality of assemblies formed by elongated actuation head 34a and spring element 39, said assemblies preferably arranged along axes that are arranged at a same angle from one another around longitudinal axis a of the lighting element, in particular, two such assemblies are arranged along axes b diametrically opposite to each other with respect to the longitudinal axis.

[0070] Two variants of the second embodiment are now described, which differ from each other in the type of spring 39 and in the way in which spring 39 is connected to elongated actuation head 34a and to fixed heat sink body 40.

[0071] Referring to Fig. 3, in a first variant of the second embodiment, spring element 39 is a tension spring arranged in through hole 22 behind elongated actuation head 34a. The spring is integrally connected to fixed heat sink body 40 and to elongated actuation head 34a. For example, spring element 39 may be a coil spring having its ends connected to fixed heat sink body 40 and to elongated actuation head 34a, respectively, so as to elongate/shorten, and preferably not to twist, upon displacing elongated actuation head 34a.

[0072] This way, by rotating elongated actuation head 34a in a predetermined rotation direction, in an step of assembling modular lighting element 100, actuation head 34a moves away from fixed heat sink body 40 and progressively extends tension spring 39, which applies a force F to the parts that are connected to its end portions, i.e. to fixed heat sink body 40, which is in a contact with the spring directly, and to movable heat sink body 20, which is in contact with the spring through elongated actuation head 34a, whereby fixed heat sink body 40 and movable heat sink body 20 are pressed against each other by this force F, which is therefore a mutual compression force for fixed heat sink body 40 and movable heat sink body 20. [0073] Referring to Fig. 4, in a second variant of the second embodiment, elongated actuation head 34a includes a shank 31 extending from a rear face of elongated actuation head 34a that is arranged within a through hole 43 of fixed heat sink body 40 and protrudes from the rear face thereof with an own enlarged abutment end portion or abutment head 32a. In this variant, spring element 39, in the form of a compression spring, is housed between a rear face 49 of fixed heat sink body 40 and a front face 32e of abutment end portion 32a of shank 31.

[0074] This way, by rotating elongated actuation head 34a in a predetermined rotation direction, in an step of assembling modular lighting element 100, elongated actuation head 34a moves away from fixed heat sink body 40 by dragging the abutment end portion 32a tha approaches therefore fixed heat sink body 40 and progressively compresses compression spring 39, which applies a force F to the parts that are respectively connected to its ends, i.e., to fixed heat sink body 40, with which the spring is in contact directly or through a washer 41a, and to movable heat sink body 20, with which the spring is in contact through shank 31 and elongated actuation head 34a, whereby fixed heat sink body 40 and movable heat sink body 20 are pressed against each other by the force F, which is therefore a mutual compression force for fixed heat sink body 40 and movable heat sink body 20.

[0075] Fig. 6 shows a common variant of the second embodiment, in which through hole 22 of movable heat sink body 20 has a stop element 34h for elongated actuation head 34a, at its own front end, i.e. at a predetermined distance D from front face 21 of movable heat sink body 20. Stop element 34h may be in the form of a restricted portion of through hole 22. Distance D is selected in such a way that elongated actuation head 34a engages with stop element 34h when spring 39 is tensioned or compressed, in the first variant and in the second variant of Figs. 3 and 4, respectively, to such an extent to express a tension or compression force having a predetermined maximum value F*. Therefore, stop element 34h acts as a stroke-limiting element, and enables mutual compression force F exerted between fixed heat sink body 40 and movable heat sink body 20 not to exceed such limit value F*, which is selected based on the same reasoning as explained when describing Fig. 5.

[0076] In Figs. 1-4, only one mechanical connecting element including a spring 39 is shown, arranged at an angular position about longitudinal axis a of lighting element 100. However, at least two mechanical connecting elements including respective springs are advantageously provided, preferably at axes b arranged at diametrically opposite positions about longitudinal axis a.

[0077] Figs. 8 and 9 are partially exploded views of lighting elements 100 in accordance with two variants of a third embodiment, in both of which LED module 80, comprising LED device 10 and movable heat sink body 20, is shown as a single assembled body, and is shown separated from fixed heat sink body 40.

[0078] According to this embodiment, mechanical connection means 30 connecting movable heat sink body 20 and fixed heat sink body 40 comprises a cam mechanism or, preferably, also in this case, at least two cam mechanisms preferably arranged at diametrically opposite positions with respect to each other, as shown in the figures. Each of said cam mechanisms comprises a cam profile 37 configured to actuate spring element 39, in the manner described below, when movable heat sink body 20 is caused to perform a rotation movement A with respect to fixed heat sink body 40, about longitudinal axis a of lighting element 100. Rotation movement A is indicated by the arrows shown in the Figs, above movable heat sink body 20, and can advantageously be caused by an unskilled operator with his/her own hands, i.e. without using any tools. Cam profile 37 can be formed in fixed heat sink body 40, in a first variant of this embodiment (Fig. 8) or, preferably, it can be formed in movable heat sink body 20, in a second variant thereof (Fig. 9).

[0079] More in detail, as Figs. 8 and 9 also illustrate, spring element 39 is a compression spring, and the cam mechanism, or each cam mechanism, further comprises a pin or shank 31 slidingly mounted within an axial through hole 23 or 43 of movable heat sink body 20 (Fig. 8) or fixed heat sink body 40 (Fig. 9), respectively. At one end thereof, shank 31 comprises an enlarged actuation head 34a protruding from rear face 29 of movable heat sink body 20 (Fig. 8) or from front face 41 of fixed heat sink body 40 (Fig. 9). At the opposite end, shank 31 further comprises an enlarged abutment head 32a, which protrudes from front face 21 of movable heat sink body 20 (Fig. 8) or from rear face 49 of fixed heat sink body 40 (Fig. 9). Spring 39 is arranged in abutment between abutment head 32a and rear face 21 (Fig. 8) or 49 (Fig. 9) facing the abutment head.

[0080] Each cam mechanism further comprises a throat 33 formed on front face 41 of fixed heat sink body 40 (Fig. 8) or on rear face 29 of movable heat sink body 20 (Fig. 9). As it can be seen looking at it from the above, throat 33 comprises a passageway portion 33a for actuation head 34a of a respective shank 31, in particular passageway portion 33a preferably has a circular cross-section larger than enlarged front actuation head 34a, so as to allow it to pass through. Throat 33 further comprises a cam slide portion 33b that extends circumferentially from passageway portion 33a and is narrower than enlarged front actuation head 34a. Cam profile 37 is made along an undercut portion of cam slide portion 33b of throat 33, at a predetermined depth from front surface 41 of fixed heat sink body 40 (Fig. 8) or from rear surface 29 of movable heat sink body 20 (Fig. 9). In this case, cam profile 37 comprises two lateral cam surfaces 37a, 37b parallel to each other and inclined inwards of fixed heat sink body 40 (Fig. 8) or movable heat sink body 20 (Fig. 9), respectively, away from respective passage portion 33a.

[0081] This way, in order to assemble lighting element 100, i.e. in order to mount LED module 80 to fixed heat sink body 40, movable heat sink body 20 is positioned with its rear face 29 in front of face 41 of fixed heat sink body 40 so that shank 31, which is mounted to either of two heat sink bodies 20,40, is aligned with passageway portion 33a of throat 33 of the other of two heat sink bodies 40,20, and is then brought next to fixed heat sink body 40, in such a way that actuation head 34a penetrates passageway portion 33a of throat 33. Subsequently, movable heat sink body 20 is caused to perform rotation movement A so that actuation head 34a laterally leaves passage portion 33a and performs a displacement B along cam slide portion 33b while remaining in contact with two lateral cam surfaces 37a, 37b, on opposite sides with respect to shank 31. The two lateral cam surfaces force actuation head 34a to progressively penetrate the thickness of fixed heat sink body 40 (Fig. 8) or of movable heat sink body 20 (Fig. 9) and cause abutment head 32a to move toward the other heat sink body 20,40, thereby progressively compressing spring 39. During rotation A, spring 39 applies a force F to the elements connected to its ends, i.e. directly to movable heat sink body 20 (Fig. 8) or to fixed heat sink body 40 (Fig. 9), and to the other heat sink body 40 or 20 through shank 31, to actuation head 34a and to lateral cam surfaces 37a, 37b, whereby fixed heat sink body 40 and movable heat sink body 20 are pressed against each other by this force F, which is therefore a mutual compression force for fixed heat sink body 40 and movable heat sink body 20.

[0082] In particular, mechanical connection means 30 comprises a plurality of assemblies formed by throat 33 with cam profile 37, shank 31, actuation head 34a, abutment head 32a and spring 39. Said assemblies are preferably arranged along axes b that are all at a same distance from one another, around longitudinal axis a of the lighting element. In particular, as shown in the figures, two assemblies are arranged along axes b diametrically opposite to each other with respect to said longitudinal axis a. [0083] In a common advantageous variant of the third embodiment, i.e. in a variant that is compatible with both variants of Figs. 8 and 9, the maximum penetration depth of lateral cam surfaces 37a, 37b from front surface 41 of fixed heat sink body 40 (Fig. 8) or from rear surface 29 of movable heat sink body 20 (Fig. 9), at the end of the sliding cam portion 33b opposite to passage portion 33a of throat 33, is preferably selected shallow enough that the spring does not become compressed beyond a limit at which the spring generates a maximum force F*, thereby providing the advantages already explained when describing Figs. 5 and 6 in connection to stroke limiting devices 34f, 34h of actuation head 34a.

[0084] Figs. 10 to 17 refer to another common variant of the third embodiment, i.e. compatible with both first variant of Fig. 8 and second variant of Fig. 9, which is taken as reference. In particular, Fig. 15 is a fully exploded view of lighting element 100, with all details shown separately, Figs. 16 and 17 are partially exploded views of lighting element 100, in which LED module 80 is shown as a single body in a mounting arrangement, separated from fixed heat sink body 40. In this variant, throat 33 with cam profile 37, i.e. with lateral cam surfaces 37a, 37b, is formed in a body 35 that is manufactured separately from movable heat sink body 20 and then mounted to it, instead of being formed directly on movable heat sink body 20. In particular, as shown in Fig. 12, such a separately manufactured body may be a cam ring 35 that is then connected coaxially with movable heat sink body 20 on rear face 29 thereof.

[0085] Preferably, cam profile 37, in particular cam side surfaces 37a, 37b as in Figs. 8 and 9, are made of brass or bronze. In particular, in the construction shown in Figs. 10-19, separately manufactured body 35 is made of one of these materials. In particular, cam side surfaces 37a, 37b are mirror polished. Moreover, preferably, each actuation head 34a and preferably the entire half 34 of each shank 13, described below, is made of stainless steel, advantageously mirror polished as well.

[0086] This way, when shanks 31 are manually inserted into throats 33, bringing actuation heads 34a into sliding contact with cam profile 37, a small manual force is sufficient to rotate movable heat sink body 20 with respect to fixed heat sink body 40, causing springs 39 to be compressed to such an extent that a strong connection between two heat sink bodies 20 and 40 is obtained, without causing any local plasticisation of the contacting portions of actuation heads 34a and cam surfaces 37a, 37b. [0087] Moreover, since components 20,31,39 and 40 are held in contact with one other by at least two springs 39, no thermal expansion of such components can lead to their temporary or permanent detachment.

[0088] Fig. 12 also shows a plurality of holes 26,36, respectively drilled in movable heat sink body 20 and in cam ring 35, to receive a same number of screws 6 (Fig. 15) in order to fix cam ring 35 to movable heat sink body 20. Holes 38 are also provided to receive the sleeves 8 inside which the spring-loaded electrical contacts 5, described below, are arranged.

[0089] Fig. 10 also shows more in detail how compression spring 39 is mounted along an outer surface 32b of shank 31, between abutment surface 32e of abutment head 32a and an abutment surface 46 that is formed, in this case, as a centring recessed portion of rear surface 49 of fixed heat sink body 40.

[0090] Figs. 10 and 11 also show LED device 10 comprising, as in Fig. 7, LED emitter 1 mounted in a central portion 11 of mounting base 2. Holes 14, also shown in Fig. 15, are drilled through mounting base 2 to receive screws 4 for fixing LED device 10 to movable heat sink body 20.

[0091] Figs. 13 and 14 show how a dissipated heat flow Q, represented by dotted dark arrows, travels both through central heat sink portions 25 and 45, which are in contact with each other at movable and fixed faces, and through movable and fixed peripheral heat sink portions, 24 and 44. This representation of the heat flow obviously applies to all the embodiments of the invention described in connection to the figures.

[0092] In the exploded view of Fig. 15, shanks 31 of mechanical connection means 30 connecting movable heat sink body 20 and fixed heat sink body 40 are shown in greater detail. In order to allow shanks 31 and springs 39 to be fitted between abutment head 32a and fixed heat sink body 40, shanks 31 are made in two halves 32 and 34, providing abutment head 32a and actuation head 34a, respectively. For each shank 31, two halves 32 and 34 are connected to each other by inserting, for example screwing or forcing, a tail portion 34c of half 34 into a central hole 32c of half 32, acting on a notch 32d with a tool, not shown, after arranging spring 39 on outer surface 32b of half 32 and after inserting the resulting shank 31 into through hole 43 of fixed heat sink body 40, with the spring resting on abutment surface or shoulder 46 of through hole 43 of fixed heat sink body 40. [0093] Figs. 15-17 also show two fixed electrical contact elements 9 and two movable electrical contact elements 5 of electrical connection means 50 for electrically connecting and powering LED device 10.

[0094] In particular, fixed contact elements 9 are housed in respective insulating bushings 7 in turn arranged within through holes 48 of fixed heat sink body 40, so that an own front portion 7a is arranged substantially flush to fixed peripheral portion 44 of front heat exchange face 41 contacting cam ring 35, as shown in Fig. 16. Bushing 7 protrudes from rear face 49 of fixed heat sink body 40 with its own small-diameter rear portion 7b, into which a cable 3 (Figs. 15 and 16) is inserted and is available for connection with an electrical power source, not shown.

[0095] Each movable contact element 5 of electrical connection means 50 comprises a conductor 5a enclosed in a rigid sheath 5b. Movable contact elements 5 are housed in respective insulating bushings 8 arranged in turn within through holes 28 and 38 of movable heat sink body 20 and cam ring 35, respectively, in such a way that conductor 5a protrudes from the latter. In a common variant of the third embodiment, a radial protrusion 5c extends from the outer surface of sheath 5b, and a compression spring, not shown, is mounted between radial protrusion 5c and an inner stop surface of bushing 8 in such a way that, in a step of mounting LED module 80 on fixed heat sink body 40, at the end of rotational movement A of movable heat sink body 20, the tip of conductor 5a is pressed against facing fixed contact element 9 arranged flush on front surface 41 of fixed heat sink body 40, and such a way that this contact condition is stable even if the temperature of modular lighting element 100 changes during the operation of LED device 10. In the figure, insulating bushings 8 have different-diameter portions 8a, 8b to stabilize their engagement within holes 28 and 38.

[0096] With reference to Fig. 18, in a common variant of the third embodiment of the invention, fixed heat sink body 40 can have a side surface with fins 77 to further improve the dissipation of the heat generated by LED device 10. The skilled person will easily extend this variant to the other embodiments of the invention, described above.

[0097] Figs. 20-29 show, in respective exploded perspective views, some examples of LED light fittings 101, 102, 103, 104, 105, 106 in which modular lighting element 100 according to the invention is used. This group of light fittings is intended to exemplify how the modular structure of the present invention can be used in light fittings that have the most diverse shapes, as suggested by design creativity, and that can be used for a wide range of both indoors and outdoors applications. [0098] More in detail, the LED light fittings of Figs. 20-29 comprise a modular structure 200 comprising lighting element 100 and a combination of auxiliary modules, in particular a lens 60 having a light aperture angle set between 2° and 60°, a spacer element 71 that can have a decorative and/or anti-glare purpose, depending on the appearance of its inner surface, and an optical filter 75, for example a honeycomb, elliptical, prismatic or corrective filter, that can be arranged within spacer element 71. Auxiliary modules 60, 71, 75 can be connected to lighting element 100, more precisely to LED module 80, by a simple operation that consists in bringing the parts to be connected next to each other and then rotating them reciprocally around the longitudinal axis of lighting element 100. In particular, an interlocking device or bayonet coupling 12-64 can be provided between a support portion 61 of lens 60 and LED module 80 of lighting element 100.

[0099] For the sake of brevity, a lighting element 100 according to the variant of Figs. 10-17 third embodiment is shown in Figs. 20-29. However, lighting elements according to the other above-described embodiments and variants can be used in LED light fittings 101-106.

[0100] Lighting element 100, together with lens 60 and spacer element 71, is housed in a housing comprising a cylindrical portion 70 and a rear end cap 73 to which cylindrical portion 70 is connected, for example by a threaded connection. Moreover, fixed heat sink body 40 is connected, for example by a threaded connection, to a heat sink cylinder 72 that can be in turn engaged or screwed to a front cylindrical protrusion of rear end cap 73.

[0101] A hole 74 is provided at the centre to rear end cap 73 for mounting cylinder container 70 and lighting element 200 contained therein to a support device that can have different shapes 95 through a connection and orientation mechanism 90 comprising a fork arm 93 and a swivelling pin 92. The single components 92-93 of the connection and orientation mechanism are of a conventional type, therefore skilled person will be to implement them by simply looking at the figures.

[0102] In particular, indoor LED light fittings 101 and 102 of Figs. 20-23 provide a ceiling mounting bracket. On the other hand, indoor light fittings 103, 104 of Figs. 24- 27 provide a track mounting element 94 for connection to a wall or a ceiling. LED light fittings 105 and 106 of Figs. 28 and 29, which can be fixed by a screw and a bracket, respectively, are conceived for outdoor use, in an IP67 or IP68 construction. [0103] Even if lighting element 100,200 in the figures always has a generally cylindrical symmetry, which is in particular the case of movable and fixed heat sink bodies 20,40, lighting elements having different shapes fall, of course, in the scope of the invention. [0104] The foregoing description of embodiments and variants of the invention is capable of showing the invention from a conceptual point of view in such a way that others, using the known technique, will be able to modify and/or adapt in various applications such embodiments without further research and without departing from the inventive concept, and, therefore, it is understood that such adaptations and modifications will be considered equivalent to the embodiments described. The means and materials for realising the various functions may be of various kinds without departing from the scope of the invention. It is understood that the expressions or terminology used are purely descriptive and, therefore, not limiting.

Claims

1. A modular structure (100,200) of a lighting element for an LED light fitting (110), said structure (100) comprising:

- an LED device (10);

- a heat sink device (20,40);

- an electrical connection means (50) arranged to electrically connect said LED device (10) to an electrical power source; wherein said heat sink device (20,40) includes:

- a fixed heat sink body (40) having a fixed central portion (45) with a front heat exchange face (41);

- a movable heat sink body (20) having a movable central portion (25) with a rear heat exchange face (29), said LED device (10) mounted integrally to said movable heat sink body (20);

- a mechanical connection means (30) between said fixed heat sink body (40) and said movable heat sink body (20), configured in such a way that said movable heat sink body (20) and said LED device (10) form an LED module (80) removable from said fixed heat sink body (40); wherein said electrical connection means (50) comprises two fixed contact elements (9) and two movable contact elements (5) on said fixed heat sink body (40) and said movable heat sink body (20), respectively, wherein said mechanical connection means (30) comprises a spring element (39) arranged to press said rear heat exchange face (29) of said movable heat sink body (20) and said front heat exchange face (41 ) of said fixed heat sink body (40) against each other by a mutual compression force (F), such that said rear heat exchange face (29) of said movable heat sink body (20) and said front heat exchange face (41) of said fixed heat sink body (40) are thermally in contact with each other, and that said movable (5) and fixed (9) contact elements are electrically in contact with each other, characterised in that said movable heat sink body (20) comprises a movable heat sink peripheral portion (24) surrounding said movable central portion (25), wherein said movable contact elements (5) of said movable heat sink body (20) lie on said movable heat sink peripheral portion (24) surrounded by movable insulating elements (8), in that said fixed heat sink body (40) comprises a fixed heat sink peripheral portion (44) surrounding said fixed central portion (45), wherein said fixed contact elements (9) of said fixed heat sink body (40) lie on said fixed heat sink peripheral portion (44) surrounded by fixed insulating elements (7), and in that said movable heat sink peripheral portion (24) and said fixed heat sink peripheral portion (44) are configured to come into a heat sink contact with each other and, simultaneously, to cause an electrical contact between said movable contact elements (5) and said fixed contact elements (9) to be established when said mechanical connection means (30) causes said rear heat exchange face (29) of said movable heat sink body (20) and said front heat exchange face (41) of said fixed heat sink body (40) to be pressed against each other by said mutual compression force (F).

2. The modular structure (100,200) according to claim 1, wherein said mechanical connection means (30) are formed on said movable heat sink peripheral portion (24) and on said fixed heat sink peripheral portion (44).

3. The modular structure (100,200) according to claim 2, wherein said mechanical connection means (30) are angularly offset at a predetermined offset angle from said fixed (9) and movable (5) contact elements.

4. The modular structure (100,200) according to claim 3, wherein said offset angle is about 90°.

5. The modular structure (100,200) according to claim 1, wherein said mechanical connection means (30) comprises:

- a shank (31) connected to said fixed heat sink body (40) and arranged through a through hole (22) of said movable heat sink body (20) to protrude with its own end portion (31a) from a front face (21) of said movable heat sink body (20);

- an actuation head (34a) on said end portion (31a) wherein said spring element (39) is a compression spring interposed between said front face (21) and a rear face (34d) of said actuation head (34a) facing said front face (21) of said movable heat sink body (20), such that, by rotating said actuation head (34a) in a predetermined rotation direction, said actuation head (34a) approaches said fixed heat sink body (40) by progressively compressing said compression spring (39) and said shank (31) pulls said movable heat sink body (20) and said fixed heat sink body (40) against each other by said mutual compression force (F), wherein, in particular, said shank (31) is integral with said fixed heat sink body (40), said end portion (31a) is threaded, and said actuation head (34a) is threaded and is screwed onto said end portion (31a); wherein, in particular, said shank (31) engages a threaded hole of said fixed heat sink body (40), and said end portion (31a) is integral with said actuation head (34a).

6. The modular structure (100,200) according to claim 1, wherein said mechanical connection means (30) comprises an elongated actuation head (34a) which is screw-engaged in a threaded through hole (22) of said movable heat sink body (20), wherein said elongated actuation head (34a) is connected to said spring element (39), whereby, by rotating said elongated actuation head (34a) in a predetermined rotation direction, in a step of mounting said modular structure (100), said spring element (39) is pulled towards said elongated actuation head (34a), such that said movable heat sink body (20) and said fixed heat sink body (40) are pressed against each other by said mutual compression force (F), wherein, in particular, said spring element (39) is a tension spring integral with said fixed heat sink body (40) and said elongated actuation head (34a); wherein, in particular, said elongated actuation head (34a) includes a shank (31) passing through a through hole (43) of said fixed heat sink body (40), and said shank (31) provides an abutment end portion (32a) configured to compress said spring element (39) against a back wall (49) of said fixed heat sink body (40).

7. The modular structure (100,200) according to claim 5 or 6, wherein a stroke-limiting element (34f,34h) configured to limit said mutual compression force (F) between said movable (20) and fixed (40) heat sink bodies.

8. The modular structure (100,200) according to claim 1, wherein said mechanical connection means (30) comprises a cam profile (37) configured to actuate said spring element (39) by a translation or rotation movement of said movable heat sink body (20) with respect to said fixed heat sink body (40), in particular, said cam profile (37) is made on said fixed heat sink body (40), and said spring element (39) is connected to an actuation head (34a) protruding from said movable heat sink body (20), such that, by said translation or rotation movement, said cam profile (37) pulls said actuation head (34a) towards said movable heat sink body (20) by tensioning said spring element (39), in particular, said cam profile is formed of a material selected between bronze and brass.

9. The modular structure (100,200) according to claim 8, wherein said cam profile (37) is made on said movable heat sink body (20), and said spring element (39) is connected to an actuation head (34a) protruding from said fixed heat sink body (40), such that, by said translation or rotation movement, said cam profile (37) pushes said actuation head (34a) towards said fixed heat sink body (40) by tensioning said spring element (39).

10. The modular structure (100,200) according to claim 9, wherein said actuation head (34a) includes a shank (31) passing through a through hole (43) of said fixed heat sink body (40), and said shank (31) provides an abutment end portion (32a) configured to compress said spring element (39) against a back wall (49) of said fixed heat sink body (40).

11. The modular structure (100,200) according to claim 10, wherein said cam profile (37) is made in a separate body (35) mounted to said movable heat sink body (20).

12. The modular structure (100,200) according to claim 1, wherein said movable contact elements (5) of said electrical connection means (50) are housed in respective insulating bushings (8) arranged in through holes (28) of said movable heat sink body (20).

13. The modular structure (100,200) according to claim 1, wherein said movable contact elements (5) protrude elastically from said movable heat sink body (20) and are configured in such a way that, in a step of mounting said movable heat sink body (20) on said fixed heat sink body (40), a tip (5a) of said movable contact elements (5) is compressed on said fixed contact elements (9).

14. The modular structure (100,200) according to claim 1, wherein said movable contact elements (5) of said electrical connection means (50) comprises a conducting element (5a) enclosed in a rigid sheath (5b), wherein a radial protrusion (5c) extends from an outer surface of said sheath (5b), and wherein a compression spring is butt-mounted between said radial protrusion (5c) and said movable heat sink body (20).

15. The modular structure (100,200) according to claim 1, wherein said fixed contact elements (9) of said electrical connection means (50) are housed in respective insulating bushings (7) arranged in respective through holes (48) of said fixed peripheral portion (44) of said fixed heat sink body (40), and are configured so as to face substantially flush with an own front portion (7a) on said fixed peripheral portion (44).

16. The modular structure (200) according to claim 1, further including an additional module selected from the group comprised of:

- a lens (60) with a light aperture angle set between 2° and 60°; - an optical filter (75);

- a decorative and/or anti-glare spacer element (71);

- a combination of the above, wherein said further module and said LED module (80) comprise a mutual connection means (12,65) configured so as to be reversibly connected to each other by means of consecutive mutual approach and rotation movements.