Abstract:
A lighting element ( 1 ) comprises at least one light ( 3 ), means ( 13 ) for delivering electricity to the or each light, a pair of spaced apart plates ( 2,2 ′), at least one magnet ( 4,4 ′) located between the said plates and biasing means ( 8 ) for biasing the said plates apart, wherein a magnet ( 4 ) is attached to one of the pair of plates. In use the lighting element forms part of a lighting system in which the element is located between spaced apart transparent sheets ( 10 ), e.g. panes of glass.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a lighting system, and in particular to a lighting system where a lighting element is mounted between transparent planar sheets. 
       BACKGROUND OF THE INVENTION 
       [0002]    Low voltage lighting is used within commercial and domestic environments, usually to produce lighting effects. Typically, low voltage lighting units consist of fixed assembled structures that are positioned and wired within the area required to be lit. Once positioned, the lighting units are stationary and rarely re-positioned. 
         [0003]    Attempts have been made to make low voltage lighting units more flexible by providing for movement of lighting units relative to a supply of electricity. 
         [0004]    DE 19826530 describes a lighting unit in which a low voltage lamp is slidably mounted on a rail. The supply of electricity is arranged such that the lamp is supplied with electricity at any position on the rail. Once a user has decided on the desired location of the lamp, the lamp is held in place by magnetic attraction between a magnet arrangement in the lamp assembly and the rail. 
         [0005]    DE 4014818 describes a low voltage lighting system comprising parallel conductor rails, which supports one or more lamps and feeds electricity to them. The lamps can be moved along the rails and are held in place by a bar-magnet, which also forms an electrical contact. 
         [0006]    Another lighting device is described in French patent application no 2,836,985. The lighting device of this patent comprises a lighting element mounted between an electrically conductive transparent surface and another electrically conductive surface. Electricity from the respective electrically conductive surfaces power the lighting element mounted therebetween. The lighting element includes two contacts each in electrical connection with one of the said electrically conductive surfaces. One of the contacts consists of a brush contact filament. The lighting element includes at least one magnet situated substantially adjacent to a backing plate. The lighting unit is held in place by a magnet aligned with the magnet of the lighting element, but on the other side of the backing plate. The lighting element may be moved by moving the magnet on the other side of the backing plate, and a hand-grip is provided to facilitate this. 
         [0007]    There is a need for an improved lighting arrangement 
       SUMMARY OF THE INVENTION 
       [0008]    According to a first aspect of the invention, there is provided a lighting element as specified in Claim  1 . 
         [0009]    According to a second aspect of the invention, there is provided a lighting system as specified in Claim  14 . 
         [0010]    According to third aspect of the invention, there is provided a method of lighting as specified in Claim  20 . 
         [0011]    The electrical power supply to the lighting element may be low voltage direct current or an alternating current from a mains supply, i.e. for the UK 240 volts at 60 Hz. 
         [0012]    The lighting system of the present invention provides a convenient means of lighting in which the lighting elements are mounted between transparent sheets and can be moved easily from one position to another simply by aligning magnets located outside the sheets with the lighting element. The magnets located outside the transparent sheet are attracted to magnets forming part of the lighting unit. The attraction of the magnets causes part of a plate mounting the lights to be pulled out of contact with an inner surface of one of the transparent sheets. This allows the lighting element to be re-positioned within the space between the sheets. The gravity switch allows the lighting elements to be switched on and off simply by rotating them. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0013]    In the drawings, which illustrate preferred embodiments of a lighting arrangement according to the invention: 
           [0014]      FIG. 1  is a schematic representation of a lighting system according to the invention mounted between panes of glass; 
           [0015]      FIG. 2  is a cross-sectional elevation of a lighting element of the system in  FIG. 1 ; 
           [0016]      FIG. 3  is a front view of the lighting element illustrated in  FIGS. 2 and 3 ; 
           [0017]      FIG. 4  is a side view of a lens of the lighting system illustrated in  FIG. 1 ; 
           [0018]      FIG. 5  is a front view of the lens illustrated in  FIG. 4 ; 
           [0019]      FIG. 6  is a cross-sectional elevation of the lighting system illustrated in  FIG. 1 ; 
           [0020]      FIG. 7  is a front view of an alternative embodiment of a lighting element; 
           [0021]      FIG. 8  is a schematic representation of a switch; and 
           [0022]      FIG. 9  is a side view of a second embodiment of a lens. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    Referring now to  FIG. 1 , a lighting element  1  is mounted between a pair of spaced apart glass panes  10 . The glass panes are conductive of electricity. In the example, the inner surface of each glass pane is coated with an electrically conductive layer  9 . The lighting element  1  includes a plurality of light emitting diodes (LED&#39;s)  3 . The central portion of each of the plates  2 ,  2 ′ is cutaway, with a ring mounting a plurality of LED&#39;s being mounted in the ring  11 . The thickness of the ring  11  is slightly smaller than the distance between the outside walls of the plates  2 ,  2 ′. The ring  11  also mounts an electrical contact element  12 , which is so dimensioned that the ends thereof brush the electrically conductive inner surfaces of the panes  10 . Power is delivered to the LED&#39;s via the electrical contact element  12  and wires  13 . The contact elements  12  may take the form of a single conductive polymer. 
         [0024]    Referring now to  FIGS. 1 to 3 , magnets  4  and  4 ′ are arranged in recesses  5  in the plates  2 ,  2 ′. The magnets  4  and  4 ′ are bonded to a respective one of the plates  2 ,  2 ′. In particular, magnets  4  are bonded to the plate  2  and magnets  4 ′ are bonded to the plates  2 ′. The plates  2  and  2 ′ include further recesses  7 , which are aligned as can be seen from  FIG. 2 . Compression springs  8  are located in the recesses  7  and serve to force apart the plates  2 ,  2 ′. The compression springs  8  may take the form of compressed foam, sponge or a plastics material. Where the springs  8  are formed from a plastics material, the springs  8  may be formed as part of the vacuum forming of one of the plates  2 ,  2 ′. 
         [0025]      FIGS. 4 and 5  illustrate a lighting element moving means in the form of a lens unit  15 . The lens unit  15  comprises a lens  16  to which is attached a backing plate  17 . The lens  16  includes recesses  18  in which magnets  19  sit The magnets  19  are enclosed by the lens  16  on one side and the backing plate  17  on the other. Alternatively, the lens unit  15  may be cast as a single part with the magnets  19  embedded therein. 
         [0026]    As illustrated in  FIG. 6 , the lens unit  15  is mounted on the outside of a glass pane  10 , and is aligned with a lighting element  1 . The magnets  19  of the lens unit  15  are attracted to the magnets  4 ,  4 ′ of the lighting element  1 . In this configuration the plate  2 ′ is caused to bend so that the outer surface of recesses  5 ′ are pulled away from the inner surface of the glass pane  10 , against the force of the springs  7 . The reduction in friction is sufficient to allow the lighting element  1  to be moved about within the glass panes  10  by a person grasping and moving the lens unit  15 . 
         [0027]    When the lens unit  15  is removed, the action of the springs  7  forces the plates  2 ,  2 ′ apart so that the outer surfaces of recesses  5 ,  5 ′ press against the inner surfaces of the glass panes  10 . 
         [0028]      FIG. 9  illustrates a second embodiment of a lighting element moving means, in the form of a lens  15 ′ in which both sides of magnets  19 ′ may be aligned with a lighting unit The magnetic surfaces of the magnets  19 ′ have north and south polarities respectively. Equally, the magnets  4 ,  4 ′ have respective north and south polarities. The lens  15 ′ of FIG.  9  can be used to move the lighting unit from either side of the glass panes  10  by presenting one side or the other of the lens  15 ′ to a respective side of the glass panes  10 . 
         [0029]    The lighting element  20  illustrated in  FIGS. 7 and 8  includes a switch  21 . The switch is in the form of an electrically conductive ball bearing  22 , which is movable between open and closed positions. The switch is operated by rotating the lighting element  20  so that the position of the switch element changes. The position of the ball bearing is controlled by gravity. When the switch  21  is less than 90 degrees away from top dead centre  23 , the switch is closed and electricity is conducted to the LED&#39;s. When the switch  21  is less than 90 degrees from bottom dead centre  24  the switch  21  is open and the LED&#39;s are off. The gravity switch allows the lighting elements to be switched on and off simply by rotating them. This switch may also take the form of a mercury reed switch. 
         [0030]    In the example, the LED&#39;s are powered by a battery or by mains electricity through a transformer. The lighting system of the invention may include solar energy collectors for collecting solar energy and converting the collected energy into electricity. Such electricity would be stored in a suitable storage device, such as a rechargeable battery, for use by the LED&#39;s when outside light conditions have dimmed. 
         [0031]    In use, a lighting system may comprise two spaced apart panes of glass  10  with a plurality of lighting elements located therebetween. Each lighting element  1  may be provided with a lens unit  15 , alternatively only one or some of the lighting elements  1  may be provided with a lens unit  15 . Where fewer lens units than lighting elements are provided, it may be necessary to remove a lens unit  15  from one lighting element  1  and move the lens unit to another lighting element, for example if the other lighting unit is to be moved. Alternatively, the lighting element moving means may not be a lens, and may be used simply to move the lighting elements from one location to another. In this alternative, it would be normal to provide fewer moving means than lighting elements.