EP0391493A1

EP0391493A1 - Pendant tube lamp system

Info

Publication number: EP0391493A1
Application number: EP90200816A
Authority: EP
Inventors: Gerardus W. A. C. M. van Wanrooij
Original assignee: VERLICHTINGSINDUSTRIE GORINCHEM BV
Current assignee: VERLICHTINGSINDUSTRIE GORINCHEM BV
Priority date: 1989-04-05
Filing date: 1990-04-05
Publication date: 1990-10-10
Also published as: NL8900838A

Abstract

A pendant tube lamp system having two or more lighting fixtures, one or more coupling pieces and two or more end parts.

The lighting fixture comprises a tubular body of plastic material, with a tube part (1) and two closing parts (2) which are slidable in said tube part and which define, together with the tube part (1), a rectangular opening (4). The tube part (1) is furthermore provided with guide channels (7,8) for a strip-shaped metal carrier (20), on which the lighting equipment is provided for emitting light through said rectangular opening.

A coupling piece comprises two or more joined tube pieces (22,23,24), adapted to the tubular body of the lighting fixture and being inclined at an angle of π/2 rad or a multiple thereof. In the housing of the coupling piece there is accommodated a coupling plate (31) for carrying connectors. When the connectors are of the spring type and are respectively aligned with a connector mounted on the metal carrier (31) of a lighting fixture, the electric interconnection can take place automatically when the coupling pieces are coupled to the lighting fixture.

An end part is at one side suitably shaped and at the other side carries coupling means for coupling to a lighting fixture.

A pendant tube lamp having a lighting fixture and two end parts.

Description

The invention relates to a pendant tube lamp system, and more in particular to a lighting fixture, coupling pieces and end parts for said system.
There is known a pendant tube lamp system, which is built up on the basis of profiled tube parts of aluminium. The tube part for the lighting fixture and the tube parts of the coupling pieces and end parts of said known pendant tube lamp system in principle have the same profile. The coupling pieces and the end parts are connected to the tube parts of the lighting fixtures by means of separate metal coupling means.
By its very nature the known pendant tube lamp system is costly and difficult to assemble for a layman.
The object of the invention is to provide a new pendant tube lamp system which is inexpensive and easy to assemble for a layman.
In order to accomplish this objective the invention provides a lighting fixture for a pendant tube lamp system, comprising a substantially tubular body of plastic material, which consists of a tube part and two closing parts, whereby the tube part has an upper side and a lower side and, in cross section, has upper and lower parts defined by the horizontal axis, the tube part at its lower side, along its entire length, being provided with two outwardly extending integral strips which define a rectangular opening in the tube part, the short side of said rectangular opening extending parallel to the horizontal axis and forming, together with the longitudinal ends of the tube part, a slideway for the closing parts, which closing parts each have a length that is essentially shorter than half the length of the tube part, and the tube part in its upper part being provided with a pair of integral guide channels, said guide channels in cross-section being located on a line which is parallel to the horizontal axis, and furthermore comprising a strip-shaped carrier of metal on which there are provided, at one and the same side, at least one lamp holder for an elongated light source and, at at least one end thereof, a connector having electric wire inlet openings accessible at said end, said carrier being accomodated in the guide channels, directed towards the rectangular opening of the tube part with its side carrying parts.
With the same objective the invention proposes a coupling piece in the shape of two or more joined tube pieces, being inclined at an angle of π/2 rad or a multiple thereof, said tube pieces having the same diameter as those of the tubular body of the lighting fixture, comprising an upper and a lower cover of plastic material, together forming the housing of the coupling piece, a coupling plate of plastic material, longitudinally accommodated in the housing, having a square connecting part and having coupling parts integrally connected to two or more sides of the connecting part, whereby said connecting part is provided, both at its upper side and at its lower side, with two tubular uprights, the ones at the upper side being longer than those at the lower side, and whereby the covers are internally provided with pin-shaped uprights engaging the tubular uprights, and whereby a connector is provided at the upper side of each coupling part, in such a manner that the electric wire inlet openings of said connector are directed towards the free ends of the coupling plate and whereby in each circular opening of the housing there is accommodated a circular coupling disc of plastic material with through holes which are located in line with the electric wire inlet openings of respective connectors on the coupling plate and on the strip-shaped carrier of the lighting fixture, whereby the coupling disc is provided, at its outwardly directed principal plane, with coupling pins for engaging the guide channels and/or the auxiliary guide channels in the tube part of the lighting fixture, and with at least one coupling flap for engaging the tube part between the guide channels and/or between a guide channel and an adjacent auxiliary guide channel.
Also in order to accomplish the same objective the invention provides an end part which is suitably shaped at one side and which supports coupling pins and at least one coupling flap at the other side.
Mechanically the pendant tube lamp system according to the invention is therefore built up of parts of plastic material. The only thing required for assembling a pendant tube lamp system according to the invention is the ready-made parts, viz. lighting fixtures, coupling pieces and end parts, to be selectively connected by snapping in, in particular when only one connector is provided in each lighting fixture.
The pendant tube lamp system is preferably suspended by the coupling pieces. Also the feed-in of the electric cable preferably takes place on the coupling pieces.
Furthermore it is possible to assemble a pendant tube lamp from a single lighting fixture and two end parts, said pendant tube lamp being suspended by the lighting fixture.
The invention will be further described with reference to the accompanying drawing, in which:

Figure 1 shows an perspective view of an end part of the substantially tubular body of the lighting fixture according to the invention;
Figure 2 shows a cross-section of one end of the end part shown in Figure 1;
Figures 3a, b show a bottom view and a sectional view respectively of the lower cover of the housing of a coupling piece according to the invention;
Figures 4a, b show a plan view and a sectional view respectively of an upper cover of the housing of the coupling piece according to the invention;
Figures 5a, b show a bottom view and a sectional view respectively of the coupling plate of a coupling piece according to the invention; and
Figures 6a, b, c show various views of the coupling disc of a coupling piece according to the invention.

Figure 1 shows a substantially tubular body of plastic material of a lighting fixture according to the invention, said body consisting of a tube part 1 and two closing parts 2, only one of which is shown. At its bottom part the tube part 1 is provided, along its entire length, with two outwardly extending integral strips 3, which define a rectangular opening 4 in the tube part 1 and which, together with the longitudinal ends of the tube part 1, form a slideway 6 for the closing parts 2, whereby said closing parts 2 each have a length which is essentially shorter than half the length of the tube part 1. The tube part 1 is in its upper part provided with a pair of integral guide channels 7, and in its lower part with a pair of integral auxiliary guide channels 8.
Referring to Figure 2 the substantially tubular body will be described in more detail. In Figure 2 the same parts are indicated by the same reference numerals as in Figure 1. Reference numeral 9 indicates the upper side of the tube part 1, whilst the lower side of said tube part is indicated by reference numeral 10. The horizontal axis has reference numeral 11 and divides the tube part 1 in an upper part 12 and a lower part 13. The two outwardly extending integral strips 3, which are preferably curved inwards, define a rectangular opening 4 (Figure 1) in the tube part 1, the short side of said opening 4, the dotted line indicated by reference numeral 14, extending parallel to the horizontal axis 11. The guide channels 7 are provided in the upper part 12 of the tube part 1 and are located on a line 15, which extends parallel to the horizontal axis 11. The auxiliary guide channels 8 are provided in the lower part 13 of the tube part 1 and are located on a line 16, which extends parallel to the horizontal axis 11, whereby the distance from the guide channels (line 15) to the horizontal axis 11 is larger than the distance from the auxiliary guide channels (line 16) to the horizontal axis 11.
Preferably the guide channels 7 and the auxiliary guide channels 8 have a circular section and a longitudinal opening which are indicated by reference numerals 17 and 18 respectively. Preferably the auxiliary guide channels 8 form stops, indicated by the reference numeral 19, for the closing parts 2. It is also preferred that the closing parts 2 have a radius of curvature which is equal to that of the tube part 1, so that a tube part 1 and a closing part 2 together form a longitudinally closed tube. The tube part 1 has a cross-sectional configuration corresponding with Ω.
Finally Figure 2 diagrammatically indicates a strip-shaped carrier 20 of metal on which there are provided, at one and the same side, the lower side 21 that is, at least one lamp holder for an elongated light source, for example two for a fluorescent lamp, and at both ends or at one end thereof a connector with electric wire inlet openings accessible at that end, whereby the carrier 20 is provided in the guide channels 17 in such a manner that the side of said carrier carrying parts, the lower side 21 that is, is directed towards the rectangular opening 4 (Figure 1) of the tube part 1. The lamp holder(s), the elongated light source and the connector are not shown in the drawing. However, the connectors are placed in the same manner as described in the explanation of the coupling piece yet to be discussed, is being described. Besides said electric parts also other electric parts may be provided on the lower side 21 of the carrier 20, such as a holder for a starter and a capacitor. The connectors, the lamp holders and the starter holder are preferably of the snap-in type, so that for their assembly it is only necessary to provide through holes in the carrier 20. Preferably the connectors, lamp holders and starter holders are substantially made of plastic material, whereby stripped electric wires can be inserted into the starter holders and the lamp holders, but said electric wires cannot be pulled out, whilst preferably this also applies to the connectors, but in the case of the connectors it applies that the stripped electric wires can be pulled out when a respective lever is pressed. The electric parts discussed are known to persons skilled in the art and are available on the market, hence said parts will not be further discussed. The same applies to all electric connections with regard to the pendant tube lamp system according to the invention. The closing parts 2 are movable in order to provide access to the electric parts on the carrier 20 and they can be snapped out in order to fit or exchange the light source, for example a fluorescent tube.
The external diameter of the substantially tubular body formed by the tube part and the closing parts 2 may for example be 50 mm, the distance between the lines 11 and 15 may be 13.1 mm, the distance between the lines 11 and 16 may be 9.8 mm and the length of the line 14 may be 36 mm. The thickness of the material of the tube part 1 and the closing parts 2 may be 1.5 mm, the radius of curvature of the strips 3 may be 23.5 mm, the centre distance of the guide channels 7 may be 36 mm and the centre distance of the auxiliary guide channels 8 may be 40 mm. The opening angle of the guide channels 17 may be 60 °C, which angle is divided in two by the line 15. The opening in the guide channels 7, which has a circular cross-section, may have a diameter of 2.7 mm, just like the auxiliary guide channels 8.
Preferably a lighting fixture according to the invention is completed such, apart from the usual electric connections, that stripped electric wire ends are inserted into both ends of the connectors, said wire ends having such a length that when a coupling piece is snapped in, said wire ends are inserted into the connector, yet to be discussed, of a coupling piece, thus effecting an electric connection.
Figures 3a, b show the lower cover of a coupling piece according to the invention, whilst Figures 4a, b show the upper cover of said coupling piece. When the upper and the lower cover are put together they form the housing of the coupling piece. Both the upper and the lower cover are made of plastic material. The upper and the lower cover are kept together by a coupling plate yet to be discussed with reference to Figures 5a, b.
In general a coupling piece according to the invention has the shape of two or more joined tube parts, making an angle of π/2 rad or a multitude thereof, said tube parts having the same diameter as the tube parts of the tubular body of the lighting fixture which has been explained with reference to Figures 1 and 2. In Figures 3a, b and Figures 4a, b a T-shaped coupling piece having three tube parts 22, 23 and 24 is concerned. The coupling piece according to the invention will be further explained with reference to the T-coupling piece illustrated in the drawing. It will be apparent, however, that the following coupling pieces will be possible. A rectilinear coupling piece consisting of two tube pieces 22, 24 which form an angle of πrad with each other, a corner coupling piece having two tube pieces 22, 23 or 23, 24, inclined at an angle of π/2 rad with each other, and a cross coupling piece having four tube pieces 22, 23, 24, 23, which each are inclined at an angle of π/2 rad. The tube pieces 23, 24, 23 successively form an angle of π/2 rad, π rad and 3π/2 rad with the tube piece 22. The open ends 25, 26, 27 of the tube pieces 22, 23, 24 respectively of the lower cover of Figures 3a, b define circular openings with the open ends 28, 29, 30 respectively of the tube pieces 22, 23 24 of the upper cover of Figures 4a, b.
Before further discussing the lower and upper covers respectively illustrated in Figures 3a, b and Figures 4a, b, the other parts of a coupling piece will first be discussed, viz. the coupling plate shown in Figures 5a, b and the coupling disc shown in Figures 6a, b, c.
The coupling plate is indicated by reference numeral 31 in Figures 5a, b. The coupling plate 31 is longitudinally accommodated in the housing defined by the lower and upper covers and is T-shaped in this case, therefore. The coupling plate 31 is made of plastic material. The coupling plate 31 is provided with a square connecting part 32, which is imaginarily indicated by a dashed line in Figure 5b. The coupling plate 31 is furthermore provided with coupling parts 33, 34 and 35, three in this case, but in general at least two, integrally connected with respective (imaginary) sides of the connecting part 32. The connecting part 32 is provided , both at the upper side 37 and at the lower side 36, with two tubular uprights, 40, 41 and 38, 39 respectively, whereby the uprights 38, 40 and 39, 41 may be continuous, as shown. The uprights 40, 41 at the upper side 37 are longer than the uprights 38, 39 at the lower side 36.
Referring back to Figures 3a, b and Figures 4a, b, the lower cover of Figures 3a, b is provided with pin-shaped uprights 42, 43, for engagement with the tubular uprights 38, 39 of the coupling plate 31 in Figures 5a, b, whilst the upper cover of Figures 4a, b is provided with pin-shaped uprights 44, 45, for engagement with the tubular uprights 40, 41 of the coupling plate 31 in Figures 5a, b. The pin-shaped uprights 42 - 45 are preferably conical, as shown.
When the coupling piece is assembled at the works the pin-shaped uprights 42 - 45 are brought into engagement with the tubular uprights 38 - 41, and the covers of Figures 3a, b and Figures 4a, b are pressed together, whereby they cannot be detached any more, owing to the conical configuration of the pin-shaped uprights 42 - 45. The pin-shaped uprights 42 - 45 may otherwise be provided with a longitudinal bore.
The lower cover of Figures 3a, b is internally provided, spaced by some distance from each end 25, 26, 27, with respective partitions 46 for supporting the coupling plate 31, in particular on the edge surfaces 47 formed by a recess 48 having a contour in the shape of a circular arc.
The upper cover of Figures 4a, b is at its upper side provided with a through hole 51 for the inlet of an electric cable (not shown). In the through hole 51 there may be provided a cable feed-through means (not shown) known per se, which at the same time or alternatively serves as the attachment for a suspension wire.
Reverting to Figures 5a, b, the coupling plate 31 is provided with through holes 52 in the coupling parts 33, 34, 35, said through holes 52 being recessed at the lower side 36, as is indicated by reference numeral 53. Said through holes 52 serve to accommodate a snap-in collector (not shown), in particular a three-gate collector having an earth tag. More in particular a connector is provided on the upper side 37 of each coupling part 33, 34, 35 in such a manner, that the electric wire inlet openings of said connector are directed towards the free ends 54, 55, 56 of the coupling plate 31.
Hereinafter the coupling disc for a coupling piece according to the invention will be discussed with reference to Figures 6a, b, c. In said Figures the coupling disc is indicated by reference numeral 57.
Reverting to Figures 3a, b and Figures 4a, b, grooves 50 are provided in the respective ends 25, 26, 27 and 28, 29, 30 defining the circular openings of the housings of the upper and the lower cover respectively, for accommodating the edge of the coupling discs 57, said edge being indicated by reference numeral 58 in Figure 6b.
Reverting now to Figures 6a, b, c, it is noted that the singly shaded parts 59, 71 in Figures 6b should be left out of consideration. The shaded parts 59, 71 will be discussed later when the end part of the pendant tube lamp system of the present invention is discussed.
As already said before, a circular coupling disc 57 of plastic material is accommodated in each circular opening of the housing, said coupling disc having through holes 60, as is shown in Figure 6c, in particular numbering three, which are located in line with the electric wire inlet openings of respective connectors on the coupling plate 31 (Figures 5a, b) and on the strip-shaped carrier 20 (Figure 2) of the lighting fixture. At its principal plane 61, which is directed outwards with respect to the coupling piece, the coupling disc 57 is provided with pairs of coupling pins 62 and 63 respectively, for engagement with the guide channels 17 and the auxiliary guide channels 18 respectively, of the tube part 1 of the lighting fixture (see Figure 2). In the embodiment shown in Figures 6a, b, c, the coupling disc 57 is furthermore provided with three coupling flaps 64 (once) and 65 (twice) respectively. The coupling flap 64 is located between the coupling pins 62 and serves to engage the tube part between the guide channels 17 (Figure 2), whilst the coupling flaps 65 are provided between a coupling pin 62 and an adjacent coupling pin 62 and serve to engage the tube part 1 between a respective guide channel 17 and a respective adjacent auxiliary guide channel 18. Instead of coupling flaps 65 a second coupling flap 64 may otherwise be provided between the coupling pins 63 whereby, moreover, the width of said flaps may be smaller than is shown in Figure 6a.
As is shown in Figure 6c the coupling disc is provided, at its other principal plane 66, opposite the principal plane 61 provided with the coupling pins 62, 63 and the coupling flaps 64, 65, with a rectilinear groove 72 for opening a respective end 54, 55, 56 of the coupling plate 31 (Figures 5a, b). The shape of the coupling flap 64 is shown in more detail in Figure 6b, said shape making a snap-in connection possible. Of course other shapes are also possible, as will be seen by a person skilled in the art. The coupling flaps 65 preferably have the same shape as the coupling flap 64. Reference numeral 67 in Figure 6b also indicates a through hole. Said through hole 67 corresponds with a through hole 68, which is provided in the tube part 1 of Figure 1. When the coupling piece, which is assembled from the parts illustrated in Figures 3a, b, Figures 4a, b, Figures 5a, b and Figures 6a, b, c, is snapped into the open end, shown in Figure 1, of the tubular body of the lighting fixture according to the invention, assembled from the tube part 1 and the illustrated closing part 2, with the carrier 20 (Figure 2) provided therein, said through holes 67 and 68 are aligned, after which a key of plastic material (not shown) can be pushed through said through holes 67, 68, for mechanical securing. As already said before, when the coupling piece is snapped in, the electric connection between the connectors of the coupling piece and the lighting fixture is at the same time effected by for example the pieces of wire, also stripped at their free ends, which are inserted in the connectors already provided on the carrier 20.
Finally the end part of the pendant tube lamp system according to the invention will be explained, likewise with reference to Figure 6b, since its shape corresponds with that of a coupling disc 57. One end part is at one side suitably shaped, as is indicated by the shaded part 59, whilst at the other side there are provided pairs of coupling pins 62 and 63 respectively. Preferably at least one coupling flap 70 is furthermore provided, said coupling flap corresponding with the doubly shaded part of the coupling flap 64 of the coupling disc 57. Preferably two such coupling flaps 70 are provided and they are reinforced by reinforcing means 71.
The tube part 1 and the closing part 2 of Figure 1, the lower and the upper cover of Figures 3a, b and Figures 4a, b respectively, and the cover part 59, 70 of the end part of Figure 6b are made of wear and impact resistant plastic material in for example the colours white, gray and black, whilst the remaining plastic parts are made of technical synthetic material. In principle the coupling discs 57 and corresponding parts 62, 63 and 70 of the end parts in Figure 6b may have the same shape, with the exception that the end part is suitably shaped at one principal plane, with a spherical part 59, whilst the coupling disc 57 is provided with the rectilinear groove 57 and the through holes 60, and is furthermore otherwise flat at the same principal plane 66.
A pendant tube lamp system according to the invention comprises at least two lighting fixtures according to Figures 1 and 2, as well as at least one coupling piece, which is assembled from the parts which are illustrated in Figures 3a, b, Figures 4a, b, Figures 5a, b and Figures 6a, b, c, whereby it should be noted that they may be coupling pieces for coupling two to four lighting fixtures. With a pendant tube lamp system such as the one just described it is possible to make closed and possibly composite figures, such as two squares which are respectively coupled at one corner point by means of a cross coupling piece. When the pendant tube lamp system furthermore comprises at least two end pieces according to Figure 6b, it is possible to compose for example rectilinear, T-shaped or cross-shaped Figures. Thus a versatile system is obtained. In the former case the pendant tube lamp system is preferably suspended by the coupling pieces, whereby at least one of the coupling pieces also or alternatively serves for the feed-in of an electric cable. In the latter case the pendant tube lamp system should also be suspended by the tube parts 1.
Also it is possible to compose a pendant tube lamp with a lighting fixture and two end parts of the pendant tube lamp system according to the invention, whereby the tube part 1 is at its upper side provided with an electric cable feed-through opening (not shown) and two openings (not shown) for accommodating a suspension means (not shown). Preferably the openings for the suspension means are provided at the ends of the tube parts 1 in that case, and the electric cable feed-through opening is provided adjacent one of the openings accommodating the suspension means.
The length of the tube part 1 may for example be 968 mm for a fluorescent lamps of 20 Watt and 1273 mm for a 30 Watt fluorescent lamp, whilst the length of the insert pieces 2 may be 205 mm.
The coupling pieces may be wired or unwired. Usually the number of couplings per electric connection is four lighting fixtures in the case of the cross coupling piece, three lighting fixtures with the T-coupling piece and and two lighting fixtures with the other coupling pieces.
Summarizing, the present pendant tube lamp system is built up of only a few parts which fully fit one another, so that they can be assembled in a quick and simple manner. The enormous gain in the time worked results from the snap system that connects the parts. Unique is the fact that the same snap system is also used for the electric connection.
The invention is not limited to the embodiment illustrated in the drawing. Furthermore there may be provided protrusions (not shown) at the outside of the coupling flaps 65 of the coupling flaps 65 of the coupling disc 57 of Figure 6b, and corresponding holes in the tube part 1 of Figure 1, instead of the through holes 68 and 67 in the tube part 1 of Figure 1 and the coupling flap 64 of the coupling disc 57 of Figure 6b respectively. The aforementioned coupling key (not shown) may be embodied in a rivet of plastic material.

Claims

1. Lighting fixture for a pendant tube lamp system, comprising a substantially tubular body of plastic material, which consists of a tube part and two closing parts, whereby the tube part has an upper side and a lower side and, in cross section, has upper and lower parts defined by the horizontal axis, the tube part at its lower side, along its entire length, being provided with two outwardly extending integral strips which define a rectangular opening in the tube part, the short side of said rectangular opening extending parallel to the horizontal axis and forming, together with the longitudinal ends of the tube part, a slideway for the closing parts, which closing parts each have a length that is essentially shorter than half the length of the tube part, and the tube part in its upper part being provided with a pair of integral guide channels, said guide channels in cross-section being located on a line which is parallel to the horizontal axis, and furthermore comprising a strip-shaped carrier of metal on which there are provided, at one and the same side, at least one lamp holder for an elongated light source and, at at least one end thereof, a connector having electric wire inlet openings accessible at said end, said carrier being accommodated in the guide channels, directed towards the rectangular opening of the tube part with its side carrying parts.

2. Lighting fixture according to claim 1, characterized in that the tube part in the lower part of said lighting fixture is provided with a pair of integral auxiliary guide channels, said auxiliary guide channels in cross section being located on a line which is parallel to the horizontal axis, whereby the distance to the horizontal axis of the guide channels is larger than that of the auxiliary guide channels.

3. Lighting fixture according to claim 1 or 2, characterized in that the outwardly extending integral strips of the tube part are curved inwards.

4. Lighting fixture according to any one of the preceding claims, characterized in that the closing parts have a radius of curvature which is equal to that of the tube part.

5. Lighting fixture according to any one of the preceding claims, characterized in that the guide channels and/or the auxiliary guide channels have a circular cross section and a longitudinal opening.

6. Lighting fixture according to any one of the claims 2 - 5, characterized in that the auxiliary guide channels form stops for the closing parts.

7. Coupling piece for a lighting fixture according to any one of the preceding claims, in the shape of two or more joined tube pieces, being inclined at an angle of π/2 or a multiple thereof, said tube pieces having the same diameter as those of the tubular body of the lighting fixture. comprising an upper and a lower cover of plastic material, together forming the housing of the coupling piece, a coupling plate of plastic material, longitudinally accommodated in the housing, having a square connecting part and having coupling parts integrally connected to two or more sides of the connecting part, whereby said connecting part is provided, both at its upper side and at its lower side, with two tubular uprights, the ones at the upper side being longer than those at the lower side, and whereby the covers are internally provided with pin-shaped uprights engaging the tubular uprights, and whereby a connector is provided at the upper side of each coupling part, in such a manner that the electric wire inlet openings of said connector are directed towards the free ends of the coupling plate and whereby in each circular opening of the housing there is accommodated a circular coupling disc of plastic material with through holes which are located in line with the electric wire inlet openings of respective connectors on the coupling plate and on the strip-shaped carrier of the lighting fixture, whereby the coupling disc is provided, at its outwardly directed principal plane, with coupling pins for engaging the guide channels and/or the auxiliary guide channels in the tube part of the lighting fixture, and with at least one coupling flap for engaging the tube part between the guide channels and/or between a guide channel and an adjacent auxiliary guide channel.

8. Coupling piece according to claim 7, characterized in that the pin-shaped uprights are conical.

9. Coupling piece according to claim 7 or 8, characterized in that at the principal plane opposite the principal plane having the coupling pins the coupling disc is provided with a groove for accommodating an end of a respective coupling part of the coupling plate.

10. Coupling piece according to any one of the claims 7 - 9, characterized in that the upper cover of the housing is at its upper side provided with a through hole for the feed-in of a electric cable.

11. Coupling piece according to claim 10, characterized in that in the through hole there is provided a cable feed-through means, which at the same time or alternatively serves as the attachment for the suspension wire.

12. Coupling piece according to claim 7 - 11, characterized in that the upper cover of the housing is provided, along its inner circumference, with perpendicularly suspended ribs for abutment against the coupling plate.

13. Coupling piece according to any one of the claims 7 - 12, characterized in that in the lower cover of the housing, spaced form the ends defining the circular openings in the housing, there are provided partitions for supporting the coupling plate.

14. Coupling piece according to any one of the claims 7 - 13, characterized in that in the upper and the lower cover of the housing, in the ends defining the circular openings of the housing, there are provided grooves for accommodating the edge of the coupling discs.

15. Coupling piece according to any one of the claims 7 - 14, characterized in that the coupling flap for engagement with the tube part of the lighting fixture is provided with a through hole between the guide channels, whereby in the tube part, at a position being in line, there is also provided a through hole for accommodating a key of plastic material.

16. Coupling piece according to any one of the claims 7 - 14, characterized in that at the outside of the coupling flaps for engagement with the tube part of the lighting fixture there are provided, between a respective guide channel and an adjacent auxiliary guide channel, protrusions for engagement with through holes provided in line with said protrusions in the tube part of the lighting fixture.

17. End part for a lighting fixture according to any one of the claims 1 - 6, characterized in that said end part is at one side suitably shaped and at the other side carries coupling pins and at least one coupling flap.

18. Pendant tube lamp system, characterized in that it comprises at least two lighting fixtures according to any one of the claims 1 - 6, and at least one coupling piece according to any one of the claims 7 - 16.

19. Pendant tube lamp system according to claim 18, characterized in that it furthermore comprises at least two end parts according to claim 17.

20. Pendant tube lamp, characterized in that it is provided with at least one lighting fixture according to any one of the claims 1 - 6 and two end parts according to claim 17, whereby the tube part is at its upper side provided with an electric cable feed-through opening and two openings for accommodating a suspension means.

21. Pendant tube lamp according to claim 20, characterized in that the openings for the suspension means are provided at the ends of the tube part of the lighting fixture, and that the electric cable feed-through opening is provided adjacent one of the openings accommodating said suspensions means.