Abstract:
An angle adjustment device comprises a support member, a plurality of holders for light emitting or receiving devices, each holder being supported by the support member for pivoting about at least one axis and an elongate spiral element which co-operates with the holders so that when the spiral element is displaced angularly about its axis relative to the support member, each holder pivots about its said at least one axis.

Description:
[0001]     This invention relates to an angle adjustment device and more particularly but not exclusively to such a device for changing a beam of light produced by a plurality of light emitting devices, such as light emitting diodes or fibre optics. Such a device has particular application in automated lighting.  
       SUMMARY OF THE INVENTION  
       [0002]     According to one aspect of the present invention there is provided an angle adjustment device comprising a support member, a plurality of holders for light emitting or receiving devices, each holder being supported by the support member for pivotable movement about at least one axis, and an elongate spiral element which co-operates with the holders so that when the spiral element is displaced angularly about its axis relative to the support member, each holder pivots about its said at least one axis.  
         [0003]     Preferably, said at least one axis of each holder extends perpendicularly or substantially perpendicularly to a radius extending outwardly from the axis of the spiral and through the holder.  
         [0004]     Preferably, the spiral element passes through an aperture in each holder or in a part connected to each holder and is slidable relative to each holder when displaced angularly.  
         [0005]     Preferably, means (typically an electric motor) is provided for angularly displacing the spiral element about its axis.  
         [0006]     Preferably, the holders are spaced apart on the support member along a spiral path. Alternatively, the holders may be spaced apart on the support member in concentric circles.  
         [0007]     Advantageously, each holder is connected to the support member by a universal joint. In this case, one or more angularly displaceable members may be connected to the holders so that when the angularly displaceable member(s) is/are displaced angularly relative to the support member, each holder pivots about a second axis extending perpendicularly or substantially perpendicularly to said one axis. The angularly displaceable member(s) is/are typically in the form of a further spiral or a plurality of spokes extending radially outwards from the axis of the first mentioned spiral. Means (typically a second electric motor) may be provided for angularly displacing the angularly displaceable member(s) relative to the support member.  
         [0008]     The angle adjustment device may also comprise a plurality of light emitting devices supported by the holders. The light emitting devices are preferably in the form of light emitting diodes (LED&#39;s) and typically in for form of white LED&#39;s each having red, blue and green guns, but they could be in the form of fibre optics.  
         [0009]     The support member may be capable of flexing and means (typically a third electric motor) may be provided for flexing the support member between a planar condition and a bowl-shaped and/or dome-shaped condition.  
         [0010]     According to a further aspect of the invention there is provided automated lighting having a source of light formed by a plurality of white light emitting diodes.  
         [0011]     The invention will now be more particularly described, by way of example, with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a plan view of one embodiment of an angle adjustment device according to the invention,  
         [0013]      FIG. 2  is a fragmentary plan view of part of the angle adjustment device of  FIG. 1  on an enlarged scale,  
         [0014]      FIG. 3  is a section taken along the line X-X of  FIG. 2  on a much enlarged scale,  
         [0015]      FIG. 4  is a view generally at right angles to the view of  FIG. 3 ,  
         [0016]      FIG. 5  is a side view showing the manner in which a holder is deflected about a radially outwardly extending axis,  
         [0017]      FIG. 6  is a plan view similar to  FIG. 2  but showing the holders deflected about the radially extending axis,  
         [0018]      FIG. 7  is a side view showing the holders deflected about an axis perpendicular to the radially extending axis,  
         [0019]      FIG. 8  is a plan view similar to  FIG. 2  but showing the holders deflected about the axis perpendicular to the radially extending axis, and  
         [0020]      FIG. 9  is a view similar to  FIG. 3  of another embodiment of an angle adjustment device according to the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]     Referring firstly to FIGS.  1  to  8  of the drawings, the angle adjustment device shown therein comprises a support member  10 , a plurality of LED holders  11  supported by the support member  10  and two spiral elements  12  and  13 .  
         [0022]     The support member  10  is in the form of a tightly wound spiral which is punched out of sheet material, typically plastics material or an aluminium alloy, and which is capable of flexing for a purpose which will become apparent hereinafter. The support member  10  is mounted in a retaining bowl  14  and has its outer peripheral edge secured to the lip of the bowl  14 .  
         [0023]     The LED holders  11  are connected to the support member  10  by universal joints  19  so that the holders  11  can pivot relative to the support member  10 .  
         [0024]     Each holder  11  has two eyelets  15  and  16 . The eyelet  15  has an elongate horizontally extending slot  17  and the eyelet  16  has an elongate vertically extending slot  18 .  
         [0025]     The first and second elongate spiral elements  12  and  13 , typically formed from relatively rigid wire, are wound through the eyelets  15  and  16 , respectively. The spiral element  13  is not attached to the eyelets  16  but is slidable relative thereto and is rotatable relative to the support member  10  by an electric motor (not shown). Rotation of the spiral element  13  will move the eyelets  16  radially inwards or radially outwards depending on the direction of rotation of the spiral element  13  and this will cause the holders  11  to tilt as shown in  FIGS. 7 and 8 . If the spacing between all turns of the spiral is equal and if the outer end of the spiral element  13  is free and allowed to wind into and out of a guide slot located around the inside of the bowl  14 , all holders  11  will be deflected by equal amounts. If the outer end of the spiral element  13  is clamped or driven by a motor at a different speed from the inner end, rotation of the spiral element  13  at the centre will cause unequal deflection of the inner and outer holders  11 . Assuming a clockwise wound spiral element  13 , clamping the outer edge of the spiral whilst the centre of the spiral element is rotated in an anti-clockwise direction will result in an increase in the spacing between the outer turns of the spiral element  13  and a tightening of the inner coils. The outer holders will then deflect more than the inner holders. If the spiral element  13  is wound so that the spacing between turns increases as it winds outwards, the outer holders will deflect more than the inner holders. Conversely, if the spiral element  13  is wound so that the spacing between turns decreases as it winds outwards, the inner holders will deflect more than the outer holders.  
         [0026]     The spiral element  12  is held captive with respect to the eyelets  15  of each holder  11  so that the spiral element  19  can slide along the slot  17  but cannot slide relative to the eyelet in the direction of the longitudinal extent of the spiral. This can be done as shown in  FIG. 4  by providing indents  21  in the spiral element  12  in which the eyelet  15  engages or by collars or washers (not shown) fixed to the spiral element  12  on opposite sides of the eyelet  15 . The spiral element  12  is angularly displaceable relative to the support member  10  by a second electric motor (not shown). Such angular movement of the spiral element  19  will cause the holders  11  to tilt about a radially extending axis as shown in  FIGS. 5 and 6 .  
         [0027]     The spiral elements  12  and  13  can be displaced by their respective motors at the same time.  
         [0028]     The eyelets  15  and  16  (and the spiral elements  19  and  20 ) could be interchanged so that the top spiral element causes deflection about an axis at right angles to a radius and the bottom spiral element produces deflection about a radially extending axis.  
         [0029]     A third electric motor (not shown) could bc provided to push the support member  10 , together with the spiral elements  12  and  13 , from the planar condition shown in the drawings into a dome-shaped condition or to pull the support member  10 , together with the spiral elements  12  and  13 , into a bowl-shaped condition. It is for this reason that the support member  10  is formed so as to be capable of flexing.  
         [0030]     In a preferred embodiment the holders  11  support white LED&#39;s each having blue red and green guns. They could however support fibre optics or lenses or light sensitive devices.  
         [0031]     Referring now to  FIG. 9  of the drawings, the spiral element  12  is replated by spokes  22 . The spokes  22  are telescopically extendible and are located below the support member  10 . The spokes  22  extend radially outwards from the axis of the spiral support member  10  and are equi-angularly spaced. Each spoke  22  comprises a plurality of sleeve-like parts  23  and a plurality of rod-like parts  24  each of which is slidably mounted in two adjacent sleeve-like parts  23  thus permitting the spokes  22  to extend and retract. The sleeve-like parts  23  are interconnected by springs  25  and the rod-like parts  24  are interconnected by springs  26 . Each holder  11  may be connected to one of the sleeve-like parts  23  by a further universal joint  27 .  
         [0032]     The spokes  22  are angularly displaceable relative to the support member  10  by an electric motor (not shown). Such angular movement of the spokes  22  will cause the holders  11  to tilt about a radially extending axis as shown in  FIGS. 5 and 6 . The holders  11  closer to the outer periphery of the support member  10  will tilt more than the holders  11  closer to the inner periphery of the support member  10  and this will change the angle and shape of the light beam emitted by LED&#39;s supported in the holders  11 .  
         [0033]     The motors can be operated in accordance with a computer program so that the angle adjustment device varies the lighting as required.  
         [0034]     The angle adjustment devices described above are particularly suitable for use in automated lighting although they could have other applications.  
         [0035]     The embodiments described above are given by way of example and various modifications will be apparent to a person skilled in the art without departing from the scope of the invention. For example, the spokes  22  or second spiral element  12  could be omitted. In this case, the holders  11  could not be tilted as shown in  FIGS. 5 and 6  but could still be tilted as shown in  FIGS. 7 and 8 . Also, the support member  10  may not be capable of flexing and may instead be of fixed planar shape or of fixed dome-like or bowl-like shape.