Abstract:
A reflector device for a luminaire, said reflector device comprising a pair of resilient sheets positioned one to either side of a spine in the manner of the pages of a book, said sheets when in an unbiased condition lying substantially in two planes intersecting at an obtuse angle and when flexed and retained against the bias of their normal resilience having a doubly arched configuration which forms a reflective surface.

Description:
RELATED APPLICATIONS 
   This application is a continuation-in-part of Ser. No. 09/548,862, filed Apr. 13, 2000, now U.S. Pat. No. 6,783,263, which is a continuation-in-part of Ser. No. 08/952,628, filed Mar. 10, 1998, now U.S. Pat. No. 6,053,624. 

   BACKGROUND OF THE INVENTION 
   This invention relates to improvements in devices for reflecting light emitted by artificial sources. 
   DESCRIPTION OF THE PRIOR ART 
   Modem industrial requirements for artificial lighting are extensive, varied, and constantly expanding. 
   Many types of reflector devices associated with artificial illumination of industrial spaces are currently known, but these all require that a fixed shape and/or a is fixed lamp mounting position within that shape be precisely specified to create optimal light distribution for a particular purpose. For example, a ‘chinaman hat’ reflector might commonly be used in a situation where a wide, uniform spread of light is required. In this case, the spreading of light is largely dependent on the fixed internal angle of the cone shaped ‘chinaman hat’ reflector. The uniformity of light emitted is therefore largely dependent on the non-adjustable lamp positioning within that reflector. These known devices have the disadvantage that their rigid, non-adjustable, designs limit their efficient use to a relatively small range of applications. 
   The present invention seeks to provide an adjustable light reflecting device which overcomes or at least ameliorates the disadvantages of the prior art. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention there is disclosed a reflector device for a luminaire, said reflector device comprising a pair of resilient sheets positioned one to either side of a spine in the manner of the pages of a book, said sheets when in an unbiased condition lying substantially in two planes intersecting at an obtuse angle and when flexed and retained against the bias of their normal resilience having a doubly arched configuration which forms a reflective surface. 
   Preferably, the sheet members are retained against the basis of their normal resilience by a retaining means linked between the sheet members. Also preferably, the retaining means is a chain, threaded rod, strip or wire or like filamentary means. Preferably the retaining means is adjustable in length, for example by nuts on a threaded rod, a wire being bent to length, a series of apertures in a strip, or a telescopic member. 
   In a preferred form, a lamp holder is adapted to be attached to the reflector device by an optionally adjustable attachment means to form a luminaire. 
   In a preferred embodiment a heat shield is provided for the luminaire. 
   Preferably, the heat shield is U-shaped or V-shaped and secured to the side of the lamp holder opposite the reflector device, and is preferably perforated. 
   In a preferred form, each of the sheets members are separately fabricated and then secured together to form the reflector device. 
   Preferably, each of the sheet members is substantially rectangularly shaped and is provided with a skirt adjacent an edge of the respective sheet and which protrudes out of the plane of the rectangle. Thus, to form the reflector device, the skirt of the first sheet is connected to the edge of the second sheet, and the skirt of the second sheet is connected to the edge of the first sheet. 
   Also preferably, the skirts and the edges are interconnected by bolts, welds or the like. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the following description of preferred but non-limiting embodiments thereof, described in connection with the accompanying drawings, wherein: 
       FIG. 1  shows an exploded view of one example of a luminaire including an adjustable reflector device according to the preferred embodiment of the present invention, 
       FIG. 2  shows a disassembled view of the skin of the reflector device, depicting the protruding skirts, present on the sheet members, 
       FIG. 3  shows an assembled view of the sheets prior to flexing, 
       FIG. 4  repeats  FIG. 3  but with a plane indicated in phantom, 
       FIG. 5  is a schematic end view of the luminaire of  FIG. 1  but without the heat shield, 
       FIG. 6  is a view similar to  FIG. 5  but with the heat shield, and 
       FIG. 7  is a view similar to  FIG. 5  but showing how the reflector can be adjusted. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Throughout the drawings, like numerals will be utilized to represent similar features, except where expressly otherwise indicated. 
   Also, throughout the specification, the term “a doubly arched configuration” is utilised to describe the shape of the reflector device when it is in its flexed position, and retained against the bias of its normal resilience, as for example, shown in  FIG. 1  of the drawings. In considering this definition, it should be appreciated that any size, shape or width of arch whether of parabolic or similarly shaped curve should be considered to fall within the scope of this definition. 
   Briefly, an adjustable light reflector device is disclosed comprising a pair of resilient reflective sheets, flexed to form a double arch or double parabolic shape. The sheets are held in place against their resiliency by adjustable retainers located at each side of the reflector device. An independently adjustable lamp mount attaches to the sheets to form a luminaire. A slide on V-shaped perforated heat shield is preferably attached to the lamp fitting. 
   Referring to  FIG. 1 , it can be seen that the adjustable reflector device according to the preferred embodiment of this invention is formed by two resilient sheet members  1  and  2 . Each sheet member  1 ,  2  preferably has two protruding skirts which extend parallel with the longer edges of the sheet member. The sheet members  1 , 2  are substantially rectangularly shaped and are detachably joined about a spine portion  3 . Then they are flexed back against their normal resilience to produce a doubly arched shape, as shown, such that one edge and the associated skirt of one sheet member neatly overlaps the corresponding skirt and edge of the other. The sheets are then flexed back to achieve a reflective doubly arched “m” shape. The sheet members  1 ,  2  may be made of any suitable material such as painted or powder coated metal, bare metal, fibreglass, or plastic. The pair of sheet members  1 , 2  could be integrally manufactured in a one piece construction—as opposed to being separately formed as illustrated. These sheets are adjustably secured by a pair of chain retainers  4  each having a pair of hooks  5  (only one retainer being shown because of the orientation). The retaining means may be a chain, threaded rod, strip, wire or like filament. The retaining means is optionally adjustable in effective length, for example by nuts on a threaded rod, a wire being bent to length, a series of apertures in a strip, or a telescopic member. 
   A pair of threaded bolts  6  and  7  pass through holes  8  and  9  in the top of the assembled skin and are secured by nuts  10  and  11 . A lamp mount  12  attaches to bolts  6  and  7  through holes  13  and  14  and is adjustably secured by attaching nuts  15  and  16 . The lamp mount comprises a sliding plate that adjusts along the pair of threaded bolts  6 , 7 . Nuts  10 , 11  are used to secure bolts  6 , 7  while nuts  15 , 16  provide a means of adjustment for the lamp mount  12 . The lamp mount  12  may be designed in any fashion, adjustable or non-adjustable, so long as it does not substantially inhibit flexibility of the sheet members  1 , 2  when attached thereto. 
   A V-shaped perforated heat shield  17  slides onto a lamp holder  18  and is secured to the underside thereof by a grub screw  19 . The heat shield  17  preferably extends along at least part of the element of the lamp, and is attached via a slender arm  29  to a piece of cylindrical tube  28  which slides onto the lamp holder  18  and is secured with the grub screw  19 . The heat shield  17  may be perforated with any number of holes  30  of any size or shape and is preferably substantially V-shaped. Depending upon the sharpness or roundness of the central ridge of the heat shield  17 , the term U-shaped can also be applied to the heat shield  17 . For example a 20 mm radius at the ridge is preferred. The heat shield  17  is able to be attached to the luminaire by any method capable of securing the heat shield  17  substantially parallel to the under side of the lamp  20 . 
   Referring to  FIG. 2  it can be seen that sheet members  1  and  2  which comprise the reflector, each have two longitudinally extending folds or bends  31 ,  22  and  21 ,  23  which create corresponding skirts  24 ,  25 ,  26  and  27 . The angle of each fold is preferably in the range of about 120° to about 140°. The folds or bends produce rigidity and strength in the flexed and retained reflector. The resilient reflector may comprise one or any number of sheet members and any necessary reinforcing members fashioned so as to approximate the predefined shape and conditions required for formation of a doubly arched configuration. 
   Referring to  FIGS. 3 and 4  it can be seen how sheet members  1  and  2  are joined at an obtuse angle. A phantom plane  100  which is substantially perpendicular to the plane occupied by sheet member  2  is illustrated in  FIG. 4 . Thus in their unbiased condition, the sheet members  1  and  2  preferably make an obtuse angle of approximately 120°–140° (more preferably 130°). 
   Skirts  27  and  25  are overlapped and attached to the bodies of the sheet members  1  and  2  to create a reinforced joint about the newly created spine  3  as illustrated so that the members  1  and  2  and spine  3  resemble the pages of a book. 
   In  FIG. 5  it will be seen that the lamp  20  emits rays in all directions. Those rays which are emitted upwardly strike the arched sheet members  1  and  2  and are then reflected downwardly. As illustrated in  FIG. 7  by flexing the sheet members  1  and  2  to a greater, or a lesser, extent as indicated by the arrows in  FIG. 7 , the nature of the reflections can be changed so as to be more concentrated or less concentrated. An important point in this connection is that since the filament of the lamp  20  is located directly below the spine  3 , no rays are reflected from the sheet members  1  and  2  back into the lamp  20 . This assists in prolonging the operating life of the lamp  20 . 
   In  FIG. 6 , the effect of the heat shield  17  is illustrated. Some rays, those illustrated by dashed lines in  FIG. 6 , emanate from the lamp  20  and pass directly through one of the holes  30  in the heat shield and thus continue directly through the heat shield  17  without deviation. Those rays which do not directly strike a hole  30  are reflected by the heat shield  17  and because of the geometry are reflected downwardly and not upwardly into either the lamp  20  or so as to strike the sheet members  1 ,  2 . As a consequence, there are no reflections from the heat shield  17  back into the lamp  20  which again prolongs lamp life. In addition, no rays are reflected twice (ie once off the heat shield  17  and then from the sheet members  1 ,  2 ). The absence of double reflections means that a high efficiency is able to be achieved. 
   The presence of the heat shield  17  means that flowers or other plants which are grown under artificial illumination provided by the lamp  20  do not suffer from is a “hot spot” directly below the lamp  20 . The effect of the heat shield  17  together with the sheet members  1 ,  2  is to provide a more even and uniform degree of illumination over a relatively wide area below the luminaire. 
   By appropriate adjustment of the reflector device described above, many and varied desirable conditions of artificial illumination can be achieved. Hence, the previous need to employ more than one reflective device to efficiently service a range of discrete tasks is reduced or abolished. 
   It will be realized that the reflector device according to this invention is not restricted to the specific shape and construction of the resilient sheets shown in the example, but may use a reflector fashioned from one, two, or more pieces of suitable material of any suitable shape or size so long as the essential feature of being flexed back against a spine or axial crease to create an adjustable doubly arched configuration or other similar shape is achieved. 
   It will be understood to persons skilled in the art that variations and modifications to the invention will be possible. All such variations and modifications should be considered to fall with the scope of the invention as hereinbefore described and as hereinafter claimed. 
   The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “having” or “including” and not in the exclusive sense of “consisting only of”.