Abstract:
A light directing duct includes a first end portion ( 2 ) and a second end portion ( 4 ), the first end portion ( 2 ) and second end portion ( 4 ) being interconnected by a hinge ( 30 ).

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to light directing ducts, for example, as used to direct light from a skylight into a room of a building.  
         [0002]     Light directing ducts, or “sun-pipes” are widely used to bring natural light into a living or working space. The sun-pipe is a tube running from the roof of the building to the ceiling of the living or working space, the inside of which is made from a light reflective material. Commonly known sun-pipes are straight tubes, running from roof to ceiling, so that the light inlet must be positioned directly above the light outlet. This necessitates the tube being cut down to fit against the slope of a roof, and means that the location one can choose to have a natural light opening in their living or work space is limited by where it is possible to make the light inlet in the roof.  
       SUMMARY OF THE INVENTION  
       [0003]     According to the present invention there is provided a light directing duct comprising a first end portion and a second end portion, the first end portion and second end portion being interconnected by a hinge.  
         [0004]     Preferably, the hinge is provided across only one side of the duct.  
         [0005]     Preferably, the first end portion comprises a tongue which extends into the second end portion. Most preferably, the tongue extends into the second end portion on a side of the duct opposite to the hinge. Preferably, the tongue is made from a flexible material, so that when the first end portion is rotated relative to the second end portion, the tongue is able to bend.  
         [0006]     Preferably, the two sides of one of the end portions adjacent to the side of the duct with the hinge, comprise projections having curved guide surfaces along which the other end portion tracks.  
         [0007]     Preferably, the internal surfaces of the duct are adapted to reflect light.  
         [0008]     Preferably, the duct has a rectangular cross section. Most preferably, the duct has a square cross section.  
         [0009]     Preferably, the duct is adapted for use between a skylight and a room of a building.  
         [0010]     Preferably, the hinge comprises a living hinge. The living hinge may be formed by scoring or otherwise weakening a sheet of material along a desired hinge line. The living hinge could be made from the same material as a wall of the duct. Preferably, the living hinge is formed from flexible material attached to a wall of the duct.  
         [0011]     Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a cross section through an embodiment of the light directing duct.  
         [0013]      FIG. 2  is a cross sectional view of a first end portion, perpendicular to the view in  FIG. 1 .  
         [0014]      FIG. 3  is a cross sectional view of a second end portion, perpendicular to the view in  FIG. 1 .  
         [0015]      FIG. 4  is a cross section through an embodiment of the light directing duct when the first end portion is rotated about the hinge.  
         [0016]      FIG. 5  is a 3-dimensional representation of the light directing duct with the first end portion rotated about the hinge. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     Referring to the drawings, FIGS.  1  to  5  show a light directing duct adapted for use between a sky light and a room of a building to bring natural light into the room. The light directing duct comprises a first end portion  2  connected to a second end portion  4  by a hinge  30 . The internal surfaces of the duct are made from a light reflecting material so that light is reflected down the duct from the skylight to the room below.  
         [0018]      FIG. 2  shows a cross section of the first end portion  2 , comprising four side walls  6 ,  8 ,  10  and  12 .  FIG. 3  shows a cross section of the second end portion comprising four side walls  16 ,  18 ,  20  and  22 . The hinge  30  connects walls  10  and  20 .  
         [0019]     A tongue  32  is fixed inside wall  16  of the second end portion and projects into the first end portion adjacent to wall  6 . Fixed inside wall  18  of the second end portion is a projection comprising a first guide plate  34  which projects into the first end portion adjacent to wall  8 , and fixed inside wall  22  of the second portion is another projection comprising a second guide plate  36  which projects into the first end portion adjacent to wall  12 . The first and second guide plates  34 ,  36  have the shape of a segment of a circle, centered on hinge  30  such that the edges  35 ,  37  of the first and second guide plates adjacent to the tongue  32  are curved.  
         [0020]     Referring to  FIG. 4 , if the first end portion  2  is pivoted about the hinge  30 , the wall  6  of the first end portion of the duct rides up the tongue  32  and the curved edges  35 ,  37  of the first and second guide plates  34 ,  36 , so that the duct becomes bent. The degree of the bend can be adjusted to match the pitch of the roof to which the duct is to be fitted. To install the duct, the second end portion  4  can be fitted first, and then the first end portion can be rotated about the hinge until the first end portion  2  abuts the roof evenly.  
         [0021]     As mentioned above, as the first end portion  2  is rotated about the hinge  30 , the wall  6 , opposites the hinge, rides up the tongue  32 , which is fixed to the wall  16  of the second end portion  4 , and slides against the inside of wall  6 . The tongue  32  is preferably made of a flexible material. The tongue is thus able to bend to seal off the gap between walls  6  and  16 . Similarly, the first and second guide plates serve to seal off the gap between walls  8  and  18  and  12  and  22  respectively, as the first end portion  2  pivots relative to the second end portion  4  about the hinge  30 .  
         [0022]     Such an arrangement ensures that no region is left uncovered when the duct is bent about the hinge and so little or no light is lost into the roof space.  
         [0023]      FIG. 5  shows a 3-dimensional representation of the light directing duct in the bent position. Clearly shown are the tongue  32  bending with the first end portion  2  and the guide plates  34  and  36  guiding the tongue.  
         [0024]     The hinge  30  may comprise a living hinge. This may be formed from the same material as the sides of the duct, or may be formed from a flexible material such as duct tape attached to the side of the duct.  
         [0025]     In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.