Patent Publication Number: US-6988525-B2

Title: Light shelf blind

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The Invention relates generally to an apparatus for control of light entering a room through a window and more specifically to a window blind with an integral, retractable light shelf. The Invention comprises a blind, which may be a roller blind, with a light shelf integral to the blind such that direct sunlight may be selectably excluded from a room while indirect sunlight may be selectably allowed to enter the room. 
   2. Description of the Prior Art 
   Window blinds, and particularly roller blinds, have been in use for many years. Typically, roller blinds are comprised of a flexible fabric housed on a spring-loaded roller and mounted at the top of a window for the purpose of shading internal room space. Such blinds are rolled (opened) and unrolled (closed) in a vertical plane in order to prevent light and/or vision from the outside of a building or between rooms in a building. 
   Light shelves also are known in the art. A light shelf is an architectural feature comprising an opaque horizontal shelf adjacent to the interior surface of a window. Sunlight entering the window and striking the top of the shelf is reflected upward into the room, illuminating the ceiling and providing indirect lighting for the room. In addition, the light shelf directly shades a portion of the room. The height of the light shelf above the floor and the depth of the light shelf are selected to achieve the desired degree of indirect illumination and the desired degree of shading of the room while preserving the function of the window of allowing visual communication with the outside. 
   Prior art light shelves are fixed and are not adjustable. Light shelves therefore are not useful to block entry of light into a room from the portion of the window above the light shelf. 
   Several efforts have been made to address the problem of light control. For example, U.S. Pat. No. 6,480,336 B2 to Digert issued Nov. 12, 2002 reveals a light shelf design in which multiple, narrow light shelves are arrayed in a fixed position along the upper portion of the inside of a window, redirecting incident sunlight toward the ceiling and providing indirect light for the room. Digert does not teach a movable light shelf and does not teach a light shelf integrated with a window blind. 
   U.S. Pat. No. 5,980,052 to Thor issued Nov. 9, 1999 teaches a mirror arranged on the outside of a window and reflecting sunlight onto the ceiling of the room inside the window. An electronic apparatus detects the position of the reflected sunlight and adjusts the angle of the mirror. Thor does not teach a light shelf and does not teach a light shelf integrated with a window blind. 
   U.S. Pat. No. 5,293,305 to Koster issued Mar. 8, 1994 teaches parallel, opaque reflective surfaces directing sunlight toward the ceiling of a room. The reflective surfaces also reflect light from an artificial light source toward the ceiling, providing indirect lighting. Koster does not teach a movable light shelf integrated with a window blind. 
   Other apparatus have been used to control entry of light into a room. For example, a variety of blades or grills may be attached to the interior or exterior of a window to control entry of light into the room. Blades adapted to move, as in the familiar miniblind, are well known to selectably control the amount of direct sunlight entering the room. The prior art does not teach a window shade integrated with a movable light shelf. 
   SUMMARY OF THE INVENTION 
   The Invention comprises a movable light shelf combined with a blind, preferably a roller blind. The combination light shelf and roller blind is mounted across the interior surface of a building window. The light shelf is movable and may be placed in an open position or a closed position. 
   When the light shelf is in the open position, sunlight entering a portion of the window strikes the upper surface of the light shelf and is reflected in a diffuse manner toward the ceiling of the room. The reflected light illuminates a portion of the ceiling, providing indirect light to the room. When the light shelf is in the closed position, the light shelf is rotated to cover a portion of the window, blocking the sun light from that portion of the window. 
   The light shelf and roller blind are integrated and supported by the same end supports. The light shelf and roller blind combination is generally mounted on the window so that the light shelf and roller blind combination is above the eye level of a user of the room. The light shelf and roller blind combination effectively divides the window into two portions. Light from the upper portion is controlled by the light shelf. Light from the lower portion of the window is controlled by the blind. 
   The light shelf and roller blind combination allows considerable flexibility. For example, the light shelf can be selectably placed in the open position, allowing diffuse illumination by sunlight, while the roller blind can be selectably unrolled (lowered) to provide shade from direct sunlight and to provide privacy. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of light shelf and blind combinations of the Invention installed on windows. 
       FIG. 2  is a perspective detail view of a portion of the Invention. 
       FIG. 3  is an end view of the Invention in operation with the light shelf and blind in the closed positions. 
       FIG. 4  is an end view of the Invention in operation with the light shelf in an open position and the blind in a closed position. 
       FIG. 5  is an end view of the Invention in operation with both the light shelf and blind in the open positions. 
       FIG. 6  is an end view of the Invention in operation with the light shelf in the damage prevention position. 
       FIG. 7  is a side view of the Invention in operation. 
       FIG. 8  is a detail side view of an alternative embodiment of the Invention. 
       FIG. 9  is an elevation of the Invention. 
       FIG. 10  is a perspective view of a detail of an end support and light shelf bracket. 
       FIG. 11  is an exploded detail of a top view of the light shelf bracket and section of the end support. 
       FIG. 12  is a perspective view of an end support. 
       FIG. 13  is a detail perspective view of a horizontal detent. 
       FIG. 14  is a detail sectional view of the horizontal detent. 
       FIG. 15  is a detail perspective view of a vertical detent. 
       FIG. 16  is a detail sectional view of a vertical detent. 
       FIG. 17  is a detail side view of an end support. 
       FIG. 18  is a detail perspective view of a light shelf bracket and end support. 
       FIG. 19  is an alternative embodiment of the Invention. 
   

   DESCRIPTION OF AN EMBODIMENT 
     FIG. 1  illustrates the combination blind  2  and integral, retractable light shelf  4  of the Invention installed on the interior of a window  6 . The light shelf  4  may be integrated with any suitable blind  2 .  FIGS. 1–9  illustrate the Invention in the context of a roller blind  8 . Other suitable blinds  2  include Venetian, vertical and mini-blinds as illustrated by  FIG. 19 . As used in the claims, the term “roller blind” includes roller blinds  8 , Venetian blinds, vertical blinds, mini-blinds and any other movable blind  2  supported on the inside of a window  6 . 
   As illustrated by  FIG. 2 , a roller blind  8  comprises a sheet of fabric  10  rolled on a roller  12  and positioned so that a user may selectably unroll the fabric  10  and cover a portion of the window  6 . The roller blind fabric  10  may be selected from any suitable material and may be opaque or translucent. The fabric  10  is housed on a roller  12 , and the roller  12  is suspended by two end support brackets  14  between the window jambs  16  or from any other suitable architectural element.  FIG. 2  illustrates the roller blind  8  manually operated by a chain  18  to roll and unroll fabric  10 . Alternatively, the roller blind  8  may be spring loaded, motor driven, operated by a cord, or rolled and unrolled by any other means known to the art of roller blinds  8 . 
   In use, and as illustrated by  FIG. 1 , the blind  2  and integral, retractable light shelf  4  are mounted to divide a window  6  into two portions: an upper portion  20  above the blind  2  and a lower portion  22  below the blind  2 . When the blind  2  is a roller blind  8 , the roller blind  8  is configured so that the roller blind  8  may selectably cover the lower portion  22  of the window  6 , providing privacy and blocking entry of direct sun light. 
   As shown by FIGS.  1  and  3 – 7 , the roller  12  of a roller blind  8  is mounted at a position below the head  24  of the window  6  to allow light to pass above the roller  12  into the room. The location of the roller blind  8  below the head  24  of the window  6  is determined by design considerations for a particular installation. In most instances the roller blind  8  and integral light shelf  4  are installed 12 to 36 inches below the head  24  of the window  6 . 
   The retractable light shelf  4  is mounted so that the light shelf  4  may selectably swivel through approximately 90° to at least two positions: an open position and a closed position. In the open position illustrated by  FIGS. 1 ,  2 ,  4  and  5 , the light shelf  4  is generally perpendicular to the window and allows sun light  40  to enter the room through the upper portion  20  of the window  6 . The sun light  40  is reflected from the upper surface  26  of the light shelf  4  onto the ceiling of the room, providing indirect lighting to the room. Indirect sun light  40  can thereby enter the room, even when the roller blind  8  is in the closed position. In the closed position illustrated by  FIGS. 3 ,  9  and  19 , the light shelf  4  substantially blocks sun light  40  from entering the room from the upper portion  20  of the window  6 . The light shelf  4  is mounted in proximity to the roller  12  of the roller blind  8  to reduce penetration of direct sun light  40  between the roller  12  of the roller blind  8  and the light shelf  4 . 
   The light shelf  4  is rotatably mounted to the end support bracket  14  and may be operated separately from the roller blind  8 . In a first embodiment illustrated by  FIG. 2 , the center of rotation of the light shelf  4  corresponds generally to the axis of rotation of the roller  12  of the roller blind  8 . In a second embodiment illustrated by  FIG. 8 , the center of rotation of the light shelf is different from the roller blind axis of rotation. 
   As shown by  FIG. 2 , the light shelf  4  is comprised of a frame  28  constructed from a relatively strong, rigid, light-weight material such as steel or aluminum. The frame  28  material may be tubular. A web  30  is supported by the frame  28 . The web  30  may comprise any suitable material, such as a synthetic or natural fabric, a paper, foam, a polymer, a sheet of metal or a piece of wood. The web  30  may be flexible or rigid. The web  30  may be a fabric selected to complement the fabric  10  of the roller blind  8  and may be opaque or translucent. The web  30  may be treated to enhance the reflection of light from the upper surface  26  of the web  30 . The web  30  may be mounted in a single layer or a double layer on the frame  28 . 
   In the embodiment illustrated by  FIG. 2 , the position of the light shelf  4  may be adjusted by adjusting the length of a cord  32  extending from a cleat  34  through an eyelet  36  and to the light shelf  4 . In the embodiment of  FIG. 2 , the position of the light shelf  4  is infinitely variable and the range of motion of the light shelf  4  exceeds 90°. 
     FIG. 3  illustrates a cross section of a wall  38  of a building with the roller blind  8  and integral light shelf  4  installed in a window  6 . In  FIG. 3 , the light shelf  4  is in the closed position. The upper surface  26  of the light shelf  4  defines a plane, and the plane defined by the upper surface  26  of the light shelf  4  is generally parallel to the surface of the upper portion  20  of the window  6 . Light  40  passing through the upper portion  20  of the window  6  and reflecting from the upper surface  26  of the light shelf  4  is reflected toward the window  6  and does not enter the room. The level of light in the room is thereby reduced.  FIG. 3  also illustrates the roller blind  8  in the closed position. Light  40  passing through the lower portion  22  of the window  6  and reflecting from the roller blind fabric  10  is reflected toward the window  6  and does not enter the room. 
   The closed position of the roller blind  8  and light shelf  4  illustrated by  FIG. 3  correspond to a low light level in the room. In an institutional setting such as a school, the low light level illustrated by  FIG. 3  is useful for showing movies, slides, overhead projector images or other demonstrations where a low light level is required. The low light level illustrated by  FIG. 3  is not possible with conventional light shelf  4  designs. 
     FIG. 4  illustrates the light shelf  4  in an open position and the roller blind  8  in a closed (unrolled) position. In the open position, the light shelf  4  is placed at a user-selected angle that serves to reflect light  40  generally toward the ceiling of the room. In the configuration illustrated by  FIG. 4 , the closed roller blind  8  prevents direct light  40  from entering through the lower portion  22  of the window  6  and further preserves privacy while the open light shelf  4  allows indirect sun light  40  to enter the room. For a vertical window  6  and a typical ceiling, the angle of the light shelf  4  in the open position generally will be selected so that the plane defined by the light shelf  4  is perpendicular to the window  6 . Any appropriate angle for the light shelf  4  may be selected to direct reflected light  40  in any desired direction. Changing the angle of the light shelf  4  to allow a change in direction of reflected sun light  40  is not possible in conventional light shelf  4  designs. 
     FIG. 5  illustrates the roller blind  8  and integral light shelf  4  both in the open position, allowing entry of indirect sun light  40  into a room through the upper portion  20  and direct sun light  40  through the lower portion  22  of the window  6 . 
     FIG. 6  illustrates the light shelf  4  in a damage prevention position. If excess force is applied to the light shelf  4 , the light shelf  4  could be subjected to damage. The light shelf  4  may be provided with horizontal detents  42 , as shown by  FIGS. 12 ,  13 ,  14 ,  17  and  18 . An excess force applied to the top surface of the light shelf  4  causes the light shelf  4  to move past the horizontal detents  42  and to assume the damage prevention position without damage to the light shelf  4  or end support brackets  14 . For a light shelf  4  controlled by a cord  32  as illustrated by  FIG. 2 , the cord  32  may be connected to the light shelf  4  with any suitable break-away connection  44 , such as a connection using hook-and-loop fasteners. A familiar example of hook-and-loop fasteners are Velcro™ brand fasteners. For a light shelf  4  controlled by a cord  32  and equipped with a break-away connection  44 , excess force applied to the light shelf  4  will cause the break-away connection  44  to separate, allowing the light shelf  4  to move to the damage prevention position and preventing harm to the light shelf  4  from the excess force. 
     FIG. 7  is a side view of the Invention installed in a window  6 . An end support bracket  14  is attached to an architectural element, in this instance a mullion  46  dividing an upper portion  20  of a window  6  from a lower portion  22  of the window  6 . The roller blind  8  is illustrated in a partially unrolled condition and the fully unrolled position is shown by dashed lines. The light shelf  4  is shown in the open position, and an alternative closed position also is illustrated by dashed lines  48 . 
     FIG. 8  is a detail of a side view of the roller blind  8  with integral light shelf  4 . An end support bracket  14  is attached to the mullion  46  of  FIG. 7  and supports the roller blind  8 . A light shelf bracket  50  is rotatably attached to the end support bracket  14  and may rotate from the open position, shown by solid lines, to the closed position, shown by dashed lines  48  in  FIGS. 7 and 8 . As noted above,  FIG. 8  shows an alternative embodiment in which the center of rotation of the light shelf  4  does not coincide with the axis of rotation of the roller  12  of roller blind  8 . The alternate embodiment of  FIG. 8  allows the light shelf  4  to be located nearer to the window  6  when light shelf  4  is in the closed position  48 , thereby blocking more light  40 . 
     FIG. 9  is an elevation of the roller blind  8  and integral light shelf  4  of  FIG. 7  as seen by a person located inside the room. The roller blind  8  and light shelf  4  both are illustrated in the closed position. The roller blind  8  has a first end  49  and a second end  51 , each supported by an end support bracket  14 . The light shelf  4  has a first end  53  and a second end  55 , each supported by a light shelf bracket  50 , which light shelf brackets  50  are in turn supported by the two end support brackets  14 . The end supports thereby support both the weight of the roller blind  8  and the light shelf  4 . 
     FIGS. 10 and 11  illustrate one embodiment of a light shelf  4  and end support bracket  14 . The end support bracket  14  supports both the roller blind  8  (not shown in  FIGS. 10 and 11 ) and the light shelf  4 . Alternatively, the end support bracket  14  may support only the light shelf  4  while the roller blind  8  is otherwise supported. A light shelf bracket  50  includes a spindle portion  52 . The spindle portion  52  is generally circular in cross section and mates with a circular spindle-receiving opening  54  in the end support bracket  14 . Annular ring  56  retains the spindle portion  52  in engagement with the end support bracket  14 . Due to the generally circular cross section of the spindle portion  52  and the circular spindle-receiving opening  54  of the end support bracket  14 , the light shelf bracket  50  may rotate while engaging the end support bracket  14 . The light shelf bracket  50  also has a frame-retaining portion  58 . The frame retaining portion  58  engages the frame  28  of the light shelf  4 , which may be tubular, rod-shaped or any other suitable shape. A screw  60  retains the frame  28  in the light shelf bracket  50  retaining portion  58 . The light shelf bracket  50  illustrated by  FIGS. 10 and 11  may be composed of any suitable material, such as a polymer. 
   As an alternative to the cord  32  controlled light shelf  4  illustrated by  FIG. 2 , each of the two end support brackets  14  may be equipped with a horizontal detent  42  and a vertical detent  62 , as illustrated by  FIGS. 10 ,  12 – 17 . The vertical and horizontal detents  42 ,  62  are springs formed from the material composing the end support brackets  14 , as by molding (if the end support bracket  14  is formed of a molded material) or stamping (if the end support bracket  14  is composed of a sheet metal or other stamped material. To move the light shelf  4  from the open to the closed position, a user rotates the light shelf bracket  50  until the light shelf bracket  50  encounters the vertical detent  62 . The user rotates the light shelf bracket  50  past the vertical detent  62 , compressing the spring formed by the vertical detent  62  and moving the light shelf  4  to the closed position. The force exerted by the vertical detent  62  must be overcome to move the light shelf  4  from the vertical to the horizontal position, securing the light shelf  4  in the closed position. 
   The horizontal detent  42  is formed in a manner similar to the vertical detent  62  and supports the light shelf  4  in the horizontal (open) position. The horizontal detent  42  also serves to protect the light shelf  4  from excess force, as by a heavy object placed on the light shelf  4 . An excessive force applied to the upper surface  26  of the light shelf  4  causes the light shelf bracket  50  to move past the horizontal detent  42  and to the damage prevention position shown by  FIG. 6 . Damage to the light shelf  4  from the excessive force is thereby avoided. 
     FIG. 18  shows an alternative construction of the light shelf bracket  50 . The light shelf bracket  50  of  FIG. 18  is formed from a sheet material, such as sheet steel, sheet aluminum or other suitable material and is rotatably secured to the end support bracket  14  by a fastener  64 , such as a bolt. The frame-retaining portion  58  of the alternate light shelf bracket  50  is rolled to receive the light shelf frame  28 . 
   As shown by  FIG. 19 , a blind  2 , such as a vertical blind, mini-blind, Venetian blind or roller blind may be supported by an elongated horizontal support member  66 . The light shelf  4  may be rotatably mounted to the elongated horizontalsupport member  66  using light shelf brackets  50  located at the first end  49  or second end  51  of the blind  2 . The horizontal support member  66  may comprise two end supports  14 , as shown by  FIG. 2 . 
   A light shelf  4  may be permanently mounted in a fixed open position should selectable closure of the light shelf  4  not be required. 
   Rotation of the light shelf  4  may be fully manual by hand or using a suitable pole. Alternatively, the light shelf  4  may be operated using a cord  32  as illustrated in  FIG. 2  or by a chain or motor drive. The operating method of the roller blind  8  may be used for operation of the light shelf  4 , but is not mandatory. 
   In describing the above embodiments of the invention, specific terminology was selected for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.