EP1710497A2

EP1710497A2 - Column lighting device with a heat dissipation device

Info

Publication number: EP1710497A2
Application number: EP06111378A
Authority: EP
Inventors: Giannunzio Guzzini
Original assignee: Iguzzini Illuminazione SpA
Current assignee: Iguzzini Illuminazione SpA
Priority date: 2005-04-08
Filing date: 2006-03-20
Publication date: 2006-10-11
Anticipated expiration: 2026-03-20
Also published as: ATE398265T1; EP1710497B1; ES2308656T3; CN1844733A; DE602006001420D1; SI1710497T1; DK1710497T3; CN1844733B; PL1710497T3; PT1710497E; NO20061492L; EP1710497A3; ITMI20050596A1

Abstract

Column lighting device (1) consisting of a supporting structure or column (2), in the upper part of which there is a light source (4), situated in a housing (3) laterally surrounded by a light passage shield (6) and above by a reflector (9) and a cover (5), comprising a heat dissipator (12), in direct contact with the reflector (9).

Description

The present invention relates to a column lighting device with particular solutions which allow the dissipation of the heat generated in its interior by the light source.
In particular, according to the present invention, a column lighting device is proposed, of the bollard type, equipped with means capable of effectively dissipating heat externally, preventing an excessive increase in the inside and outside temperature.
Column lighting devices of the known type, also called bollards, can be divided into two groups, with respect to the positioning of the light source and, inevitably, heat : column lighting devices in which the light source is situated in the upper part of the column and column lighting devices in which the light source is situated in the lower part of the column.
The heat dispersion capacity towards the outside of the devices of the first group, depends to a large extent on the size of the shield, i.e. of that portion of their side surface, situated at a height coinciding with or close to that of the light source, which allows the passage of light towards the outside. On the basis of the size of the shield, these light devices can be subdivided into two subgroups: a first subgroup in which the shield has reduced dimensions and consequently a lesser capacity of dispersing heat externally, and a second subgroup in which the shield has ample dimensions and consequently a greater capacity of dispersing heat externally.
In the devices belonging to the first subgroup, which are preferred as, in virtue of the reduced dimensions of the shield, they allow a greater visual comfort to be obtained, it is therefore necessary to use glass shields which resist the high temperatures reached, but which do not have characteristics of infrangibility and are consequently particularly subject to damage. In some cases, attempts have been made to solve this problem by giving the lighting device a form availing of protected positions for the glass shield, but undesirably reducing the lighting capacity of the device.
In the lighting devices belonging to the second subgroup, on the other hand, due to the greater dispersion of heat towards the outside and lower temperatures reached, it is possible to produce a shield made of thermoplastic material, which is infrangible but to the detriment of the visual comfort as dazzling phenomena can arise, i.e. the direct light emitted from the light source reaches the eyes of an observer.
With reference to the lighting devices of the second group, i.e. column lighting devices in which the light source is situated in the lower part of the column, the outward dispersion of heat produces fewer difficulties. In this type of lighting device, in fact, as the shield is in any case situated in the upper portion of the column, the light emitted from the light source must pass through a space which extends as far as a reflector element, situated close to the shield, which reflects it outwardly. As a result of the greater distance between the light source and the shield and the large volumes of the space which houses the light source and which allows the light emitted therefrom to reach the reflector element, the temperature inside the device reaches less high temperatures with respect to the devices in which the light source is positioned in the upper portion of the column. In particular, the shield reaches lower temperatures. This type of lighting device therefore allows shields with reduced dimensions to be produced, satisfying the requirements of visual comfort and at the same time allowing thermoplastic materials to be used for the shield, obtaining characteristics of infrangibility. The limit of these devices, however, consists in the low lighting yield due to the non-optimum reflection capacity of the light towards the outside.
A main objective of the present invention is therefore to provide a column lighting device which is able to combine the demands for visual comfort, by means of a shield with reduced dimensions, with those of safety and mechanical resistance, maintaining the temperature within such limits as to allow the use of thermoplastic and infrangible materials, without jeopardizing the lighting yield.
A further objective of the present invention is to provide a column lighting device which is easy and economical to produce and handle.
These objectives according to the present invention are achieved by providing a column lighting device having the characteristics specified in claim 1.
Further characteristics of the column lighting device of the present invention are indicated in the subsequent dependent claims.
The characteristics and advantages of a column lighting device according to the present invention will appear more evident from the following illustrative and non-limiting description, referring to the enclosed drawings, in which:

figure 1 shows a sectional view of the upper portion of a column lighting device according to the invention, in a first embodiment;
figure 2 shows a sectional view of a detail of the upper portion of a column lighting device according to the invention, in a second embodiment; and
figure 3 shows a sectional view of a detail of the upper portion of a column lighting device according to the invention in a third embodiment.

With reference to figure 1, the upper portion 1 of a column lighting device according to the present invention is sustained by the walls 2 of a supporting column, and comprises a housing 3 for a light source 4, in turn covered by a cover 5. The portion of the side surface of the housing 3 which allows the passage of light, i.e. which is included between the upper edge of the walls 2 of the supporting column and the lower edge of the cover 5, represents the light passage portion of the lighting device and consists of a shield 6, made of a light transparent material, preferably a thermoplastic and infrangible material such as polycarbonate.
The light source 4 consists of an emitting bulb 7, surrounded by a glass ampoule 8. The emitting bulb 7 is situated at a greater height with respect to the shield 6. Immediately above the emitting bulb 7, there is a reflector 9, with a curved section, having a concavity facing downwards.
The reflector 9, in the embodiment shown in figure 1, is centrally perforated to allow it to be positioned slightly above the emitting bulb 7, i.e. to house the upper part of the ampoule 8 in the space defined between the reflector 9 and the cover 5.
Around the light source 4 there is a cylindrically-shaped, transparent casing 10, preferably made of glass, optionally coloured, which completely surrounds the light source 4 and physically separates the central housing area 3, which houses the light source 4, from the more peripheral areas of the same housing 3. The function of the casing 10 is to prevent an excessive overheating of the air in the housing 3, the hot air rising upwards and being sent through the single opening in correspondence with the central hole of the reflector 9.
Around the light source 4, there is also a light absorbing shield 11, whose upper edge is situated slightly below the position of the emitting bulb 7, and is at least at the same height as the lower edge of the cover 5. The function of the shield 11, in cooperation with the edge of the cover 5, is to prevent light from being emitted from the lighting device 1 in a direction parallel to the ground.
Above the reflector 9, and directly in contact with this, there is a dissipator 12, whose form largely corresponds to that of the reflector 9 to maximize the contact surface therewith, in the central portion, in correspondence with the perforation of the reflector 9, it defines a cylindrical recess 13 for the housing of the portion of the light source 4 which passes through the hole of the reflector, and in the peripheral portion it has a flap 14 for coupling with a support 15 and which is in contact with the cover 5. On the upper side of the dissipator 12 there is a series of ribbings 16, whose function is to increase the radiating surface and allow a more effective dispersion of heat upwards. A part of the dissipator 12 is in direct contact with the cover 5 of the lighting device.
The dissipator 12 acquires heat in its lower portion and releases it through its upper portion. In particular, the dissipator 12 is heated by direct irradiation on the part of the light source 4, and to a minimum extent by air convection, in particular in correspondence with its portion which defines the recess 13 which houses the upper portion of the light source 4, and by conduction in its portion in contact with the reflector 9. The dissipator 12 releases heat by irradiation and convection through its upper surface, maximized by the presence of the ribbings 16, and by conduction through its portion in contact with the cover 5.
The support 15 is coupled with the shield 6 (in turn fixed to the body of the column of the lighting device) and therefore with the rest of the lighting device, as well as with the dissipator 12 and the cover 5.
In particular, the coupling between the cover 5 and the support 15 is obtained by the housing of a series of conical teeth 17 of the cover 5 in corresponding conical seats 18 of the support 15. The fixing between the cover 5 and the support 15 can be ensured by a single headless screw 19.
Once the cover 5 has been correctly coupled with the support 15, the contact between the flap 14 of the dissipator 12 and the cover 5 is also guaranteed.
In a preferred embodiment, shown in the figures, the cover 5, which can have any form, is also equipped on the inner side with a series of ribbings 23 arranged in the perimetric portion in contact with the flap 14.
The coupling means between the various elements of the column lighting device according to the embodiment illustrated in figure 1 are all situated inside the body of the device and are invisible from the outside, except for the headless screw. The outer surface of the device is aesthetically extremely clean.
With reference to figures 2 and 3, these show alternative embodiments of the couplings between the shield 6, the support 15, the dissipator 12 and the cover 5, the remaining aspects of the lighting device shown being identical to those illustrated in figure 1.
In particular, in the embodiment shown in figure 2, the dissipator 12 substitutes the support 15 in its coupling function with the cover 5, as it is equipped with conical seats 20 for the conical teeth 17 of the cover 5, and its more peripheral portion 21 is visible from the outside, covering part of the shield 6.
In the embodiment shown in fig. 3, on the other hand, it is the support 15 which is conformed so that its more peripheral portion 22 is visible from the outside and covers part of the shield 6.
Embodiments in which the coupling between the cover 5 and the underlying support 15 (i.e. the dissipator 12, in the embodiment shown in figure 2) is ensured not by one but by several headless screws screwed onto the cover, which are inserted in corresponding conical seats present on the underlying support 15 (or the dissipator 12), should obviously be considered perfectly equivalent to the embodiments illustrated with the help of the enclosed figures.
The cover 5 of the lighting device can also be fixed to the underlying element by other coupling means, with screws or by insertion.
The column lighting device according to the present invention allows an optimum and uniform heat distribution over the whole upper portion, and in particular on the whole surface of the cover 5, avoiding overheating of the specific portions of the surface.
Furthermore the column lighting device according to the present invention forms a solution which is simple and economical to effect and handle.
The present invention is described for illustrative and non-limiting purposes, according to one of its preferred embodiments, but variations and/or modifications can obviously be applied by experts in the field, all included in the protection scope, as defined by the enclosed claims.
In particular, the forms, as also the materials, of the lighting device of the invention can differ from those shown for purely illustrative purposes.

Claims

A column lighting device (1) consisting of a supporting structure or column (2), in the upper part of which there is a light source (4), situated in a housing (3) laterally surrounded by a light passage shield (6) and above by a reflector (9) and a cover (5), characterized in that it comprises a heat dissipator (12), in direct contact with the reflector (9).
The lighting device (1) according to claim 1, characterized in that most of the surface of the lower side of said dissipator (12) is conformed so as to adhere to the rear surface of said reflector (9).
The lighting device (1) according to claim 1 or 2, characterized in that a series of ribbings (16) is present on the upper side of said dissipator (12).
The lighting device (1) according to any of the previous claims, characterized in that said dissipator (12) comprises at least one portion in direct contact with said cover (5).
The lighting device (1) according to any of the previous claims, characterized in that said reflector (9) has a perforation in correspondence with which said dissipator (12) defines a recess (13), for the housing of the portion of the ampoule (8) of said light source (4) which is situated above the emitting bulb (7).
The lighting device (1) according to any of the previous claims, characterized in that it also comprises a connecting support (15) between said dissipator (12) and said cover (5).
The lighting device (1) according to any of the previous claims, characterized in that on the lower side of said cover (5), there is a series of ribbings (23).