Reflector type fluorescent fitting

Abstract

 Reflector type fluorescent fitting, comprising an elongated housing (1) provided with means (2;3) for accommodating the end faces of one or more elongated fluorescent tubes. The housing (1) comprises a compartment (4) which extends over the length thereof and is bounded by a fixed wall (6) and a detachable wall (7;20) which is situated at the side of the fluorescent tubes, and in which compartment (4) electric circuit arrangements (5) for the fluorescent tubes are accommodated. The housing (1) also comprises wall parts extending (8a;8b) over the length of the housing (1) and on either side beyond the width of the compartment (4) for the electric circuit arrangements (5).
The fixed wall (6) of the compartment (4) for the electric circuit arrangements (5) and the wall parts (8a;8b) of the housing (1) projecting on either side beyond said compartment (4) are formed from a single piece of material, preferably sheet material.

Description

[0001] The present invention relates to a reflector type fluorescent fitting according to the preamble of claim 1.

[0002] Such light fittings have already been in production and on sale in large numbers for many years.

[0003] In DE 973 599 a light fitting according to the preamble of claim 1 is disclosed. The housing of this known fitting comprises a fixed wall having an essentially U-shaped cross-section and a detachable wall which covers the open side of the U-shaped fixed wall to form a closed compartment for the electric circuit arrangements for the fluorescent tube(s). The housing of the known fitting further comprises two elongated reflector panels, which are manufactured as separate parts. The reflector panels are fitted on opposite sides to the U-shaped wall of the housing, which U-shaped wall is provided with a special profile for receiving the edge regions of the reflector panels.

[0004] EP 0 621 444 also discloses a light fitting according the preamble of claim 1 in an embodiment which is nowadays considered to be the standard design. As described in the introduction of this publication, these fittings are generally used for the lighting of a commercial building, where several fittings are fixed, resting end to end against each other, in a single row below a ceiling, an arrangement which is known as a continuous fluorescent luminaire. Of course, individual placing is also possible. In particular, it is pointed out that reflector type fluorescent fittings are not integrated into a (false) ceiling.

[0005] In the case of this known fitting the housing, which is essentially made of thin metal plate, consists of an elongated supporting bar which has an essentially U-shaped cross-section and is suspended below the ceiling with its open side facing downwards, directly or by means of suspension rods or chains. The housing also comprises an elongated part which is to be fixed detachably to the support, and which is intended for fitting in the opening of the U-shaped support. In the case of this known fitting the electric circuit arrangements, also known as ballast, for the fluorescent tube (or tubes) and the other electrical devices are fitted on said detachable part of the housing. If said detachable part is fitted on the support, the two parts bound an elongated compartment for the ballast, in which case the support forms the fixed wall of said compartment and the detachable part forms the detachable wall of said compartment.

[0006] For the protection of the fluorescent tube situated below the support and/or for the reflection of the radiated light, reflector type fluorescent fittings have on either side wall parts which project beyond the width of the compartment for the ballast. Said projecting wall parts project so far outwards that the fluorescent tube(s) lie(s) fully within the space bounded by said wall parts and the light output window formed by the free longitudinal edges of said wall parts.

[0007] In the case of the known reflector type fluorescent fittings, such as those disclosed in DE 973 599 and EP 0 621 444, the wall parts projecting widthwise beyond the compartment for the ballast are formed by one or more separate parts of the housing. With fitting as disclosed in EP 0 621 444 this part usually has a pan-shaped or trough-shaped cross-section and, prior to fitting of the fluorescent tube, is fixed against the part of the housing which forms the detachable wall of the compartment for the ballast. This latter part can then already have been fitted on the support suspended below the ceiling.

[0008] The object of the present invention is to provide an improved light fitting of the type mentioned in the preamble. In particular, the object of the invention is to provide a fitting which is a simpler construction and can consequently be produced more cheaply.

[0009] To this end, the present invention provides a light fitting of the type mentioned in the preamble of claim 1, which is characterized in that the fixed wall of the compartment for the electric circuit arrangements and the wall parts of the housing extending beyond said compartment form part of a single piece of sheet material, and each leg of the U-shape of the fixed wall merges by way of a bending line into the adjacent outward projecting wall part.

[0010] As a result of this measure, the housing now in fact consists of only two parts, namely a first part having a U-shaped wall and at each side a reflector wall extending sideways therefrom and a second part forming the detachable wall. The first part can be produced from a single piece of metal sheet by conventional methods, such as bending or rolling, with the result that a substantial reduction in production costs can be obtained by comparison with the light fittings assembled in the known manner. The measure according to the invention also means that the fitting is considerably more rigid than the known fittings. In the case of the fitting according to the invention the wall parts of the housing projecting beyond the compartment for the ballast make a considerable contribution to the rigidity of the entire fitting. In the case of the fitting known from EP 0 621 444 the part forming said projecting wall parts is fixed only at some points to the support and generally with some play, in order to facilitate the fitting and removal of said part, so that said part makes no relevant contribution to the rigidity, in particular to the torsional rigidity of the fitting. The increase in rigidity of the fitting is advantageous, inter alia, when the fitting is being handled while being suspended below a ceiling.

[0011] Further advantageous embodiments of the invention are described in subclaims.

[0012] The invention will be explained in greater detail below with reference to the drawing, in which:

Fig. 1 shows diagrammatically a cross-section of the housing of a preferred embodiment of the light fitting according to the invention;

Figs. 2a and 2b show longitudinal sections of the two end faces of the fitting of Fig. 1;

Figs. 3a and 3b show partial bottom views of the two end faces of the fitting of Fig. 1; and

Fig. 4 shows diagrammatically a cross-section of the housing of another preferred embodiment of the light fitting according to the invention.

[0013] The relector type fluorescent fitting shown in Figures 1, 2a, 2b, 3a and 3b comprises a housing 1 which is made of metal sheet and near each end face thereof is provided with a fitting 2, 3 which is known per se, for accommodating two fluorescent tubes next to each other. The length of the housing 1 is adapted to the length of the fluorescent tubes; standard lengths for the tubes are, for example, 1200 mm or 1500 mm.

[0014] It can be seen clearly from the cross-section of Fig. 1 that the housing 1 contains a compartment 4 extending over the length thereof, which is usual in the case of fittings of this type. The compartment 4 has an essentially U-shaped cross-section, the open side of the U-shape facing the fluorescent tubes. The compartment 4 contains the electric circuit arrangements, also known as ballast, 5 necessary for switching on the fluorescent tubes and possibly has other electric features. Said ballast 5, which generally has standard dimensions, is indicated by dashed lines in Fig. 1.

[0015] The compartment 4 is bounded in the radial direction at one side by a wall 6, which in the context of the present invention is indicated as the fixed wall and consists here of a top wall part 6a and two vertical side wall parts 6b and 6c.

[0016] The top wall part 6a is provided (in a manner not shown in any further detail) with means for fixing the fitting below a ceiling. The fitting can be fixed directly against the bottom of the ceiling, but it will often be suspended, for example by means of chains or rods, below the ceiling.

[0017] The side of the compartment 4 facing the fluorescent tubes is shut off by a detachable wall part 7. The wall part 7 has flanged longitudinal edges, in order to increase the rigidity of said part 7.

[0018] The housing 1 also comprises wall parts 8a and 8b which extend over the length of the housing 1 and at either side beyond the width of the compartment 4 for the switching gear. Said wall parts 8a and 8b have such dimensions that the fluorescent tubes lie completely in the space bounded by the wall parts 8a and 8b and the light output window formed by the two wall parts 8a and 8b. As a result of this design of the fitting, the wall parts 8a and 8b, on the one hand, serve as protection for the fragile tubes and, on the other hand, reflect the light radiated by said tubes.

[0019] According to the present invention, the wall parts 8a and 8b and the wall parts 6a, 6b and 6c indicated as the fixed wall of the compartment 4 form part of a single piece of sheet material. It is clear that the shape shown and any variants thereof can be produced very simply by means of bending and the like. This design according to the invention thus clearly differs from the design generally known until now for this type of light fitting, since the wall parts 8a and 8b in the case of the known trough fitting are not connected to the fixed wall 6 of the compartment 4, but at their longitudinal edges lying close to each other (the position of which is indicated by 9a and 9b in Fig. 1) are interconnected by a strip of sheet material, and thus form a separate part. This separate part then has to be attached to the fixed wall of the compartment by means of additional fixing means.

[0020] At both end faces the compartment 4 is shut off by end pieces of metal sheet, 10 and 11 respectively, which are fixed to the wall 6 by spot welding. End piece 10 is provided with a lip 12 which is bent out downwards, so that the detachable part 7 can be slid between said lip 12 and the part of the end piece 10 which is not bent out. At the other end, the wall part 7 can be attached to the end piece 11 by means of a screw bolt 13. In order to facilitate the removal of part 7, the end part 15 of wall part 7 situated at screw bolt 7 is flanged and provided with an opening 16 there. The screwdriver needed to unscrew bolt 13 can then be inserted into the opening 16, in order to lift up the wall part 7.

[0021] The fitting shown in Figure 4 corresponds largely to the fitting shown in Fig. 1, and corresponding parts thereof are therefore provided with the same reference numbers. The important difference is the presence of an aluminium reflector 20. The reflector 20 is designed in such a way that it also forms the detachable wall part of the compartment 4, so that the wall part 7 is omitted. In this case it is advantageous if the ballast and other devices are attached directly to the fixed wall of the compartment 4.

Claims

1. Reflector type fluorescent fitting, comprising an elongated housing (1) made essentially of sheet material and provided with means for accommodating one or more elongated fluorescent tubes, in which the housing comprises a compartment (4) which extends over the length thereof and in which electric circuit arrangements (5) for the fluorescent tubes are accommodated, which compartment is bounded by a fixed wall (6) and a detachable wall (7; 20) which is situated at the side of the fluorescent tubes, while the fixed wall (6) of the compartment for the electric circuit arrangements is essentially U-shaped in cross-section with the open side facing the fluorescent tubes, and the housing also comprises wall parts (8a, 8b) extending over the length of the housing and on either side beyond the width of the compartment for the electric circuit arrangements, characterized in that the fixed wall (6) of the compartment (4) for the electric circuit arrangements and the wall parts (8a, 8b) of the housing (1) extending beyond said compartment form part of a single piece of sheet material, and each leg of the U-shape of the fixed wall (6) merges by way of a bending line (9a, 9b) into the adjacent outward projecting wall part (8a, 8b).

2. Fitting according to claim 1, in which the electric circuit arrangements are fixed to the detachable wall of the compartment.

3. Fitting according to one or more of the preceding claims, in which an aluminium reflector (20) is fitted between the housing (1) and the fluorescent tubes.

4. Fitting according to one or more of the preceding claims, in which a reflector (20) is fitted between the housing (1) and the fluorescent tubes, and said reflector (20) forms the detachable wall of the compartment for the electric circuit arrangements.

Drawing