Abstract:
A hinge retaining mechanism for a fluorescent lighting system. A portable fluorescent lighting system which utilizes an extremely lightweight corrugated plastic panel made into 5 subpanels. At each end of the panel a U shaped channel is attached that forms the center panel and the opposing adjacent two panels into a trough or recessed pan. On each of the two remaining panels is attached another U shaped channel. Each of the U shaped channels includes a mechanism for supporting a high-tension mechanical hinge. The mechanical hinge is designed to float freely within the adjacent channel brackets. One part of the hinge is mechanically retained to the channel to prevent inadvertent removal of the hinge.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a portable and lightweight fluorescent lighting system suitable for use in the field of photography, television and motion pictures utilizing fluorescent lamps. 
     2. Description of the Prior Art 
     U.S. Pat. No. 5,132,885 disclosed a portable fluorescent lighting system. This system comprised of 5 corrugated panels that formed the basis of a lighting fixture. The five panels were created from one piece of corrugated polypropylene plastic. The panels were established by removing two to three upright flutes and one skin of corrugation between each panel. The remaining material formed a living hinge joining the 5 panels. The ends of the panel contained a U channel that carried a flexible metal wire that acted as a retention mechanism for holding the orientation of the panels once they were positioned by the user. The lighting system became very popular in motion picture lighting applications. The hinge retention mechanism being made of flexible metal wire had a given life span due to metal fatigue. After the metal fatigue resulted in the failure of the wire it would have to be replaced. Improvements were made along the way in which the flexible wire was encased in a flexible metal shield. This shield prevented sharp bends in the wire that would lead to premature wire fatigue and failure and thusly extended the life span of the wire. 
     Attempts at improving on the wire retention mechanism were challenging in that the panels do not pivot on a central point. Instead they pivot from one side of the living hinge. The original wire retainer concept was very low cost and very light weight. Applying conventional hinges to the fixture design never worked due to the pivot centers always being off center. Replacing the living hinge with a conventional hinge dramatically increased the cost and weight of the fixture as well as assembly costs. There was never a viable solution to improving on the hinge. 
     Various attempts have been made by others to construct a low maintenance hinge retention mechanism for this style of fixture. Film Gear, a Chinese manufacturer constructed a mechanism that comprised many parts that added weight and was costly to construct. They relied on a complex series of broad shallow U channels in which conventional hinge elements would slide back and forth under tension. The panels relied on the tension of the sliding hinge elements binding with the edges of the U channel. Over time this tension would lessen and fail to support the panels. The high assembly cost, weight and limited mobility of the mechanism were not considered a product enhancement. The performance of this hinge over time did not live up to the claims of superiority. When it required replacement the process was also labor intensive. This approach never found market acceptance. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the issue of hinge wire maintenance by presenting a low cost high-tension mechanical retention hinge while not adding weight. The hinge construction takes into account the off center pivot point of the panels. It is designed for robust manipulation, low cost, ease of manufacturing and long tension life. It is designed for easy field replacement should the necessity ever arise. 
     The new design also allows for mounting pads to hold accessory honeycomb louvers used in directing the light as well as an accessory that blocks light from exiting the ends of the fixture. 
     This invention entails a lighting fixture having 5 panels. The invention has four primary elements: 
     1. premolded central panel U channel with accessory holder; 
     2. premolded outer subpanel U channel; 
     3. premolded high tension retainer hinge; 
     4. flexible light shield. 
     A premolded central U channel made of high impact plastic is mechanically fastened to the central and two secondary subpanel elements. This form is common to the opposing end of the fixture. The molded channels retain the three panels in a rigid trough configuration. The central panel U channel is configured to hold a lamp harness strain relief. The strain relief mechanism uses a ¼ turn fastener such as manufactured by Southco and a cable tie that wraps around the harness cable. The central panel U channel also has accommodation for an accessory holder for mounting lighting control louvers. 
     Premolded outer subpanel U channels are fastened to the four remaining panel ends. Each U channel includes a receiver channel designed to receive the piston arm of a retention hinge. It is sized so as to allow the piston arm to move freely with minimal friction. 
     A high-tension hinge retainer is made from a hinge mechanism that is commonly used by laptop computer manufacturers. This hinge mechanism is molded into two plastic piston arms. The arms are of two differing lengths. Each arm is designed to insert into receiver channels on the central U channel and the outer subpanel U channel. The arms include ridges or the like designed to fit snuggly into the channels yet provide minimal friction surface. The minimal friction allows free movement of the piston arms as the panels are oriented. The allowance for movement takes into account the panel displacement variances as the panels are manipulated. One of the piston arms has an oblong slot along the center. A fastening device such as a pin is inserted through the central U channel so as to capture the piston arm with a slotted end. The pin is removable to allow for replacement of the retainer hinge. 
    
    
     
       BRIEF DESCRIPTION OF THE INVENTION 
         FIG. 1  is a perspective view of the front of a fluorescent lighting system in accordance with the invention. 
         FIG. 2  is a perspective view of the rear view of the fluorescent fixture. 
         FIG. 3  is an exploded view of the premolded outer subpanel U channel, the premolded retainer hinges and the premolded central U channel form. 
         FIGS. 4   a - 4   e  are detailed perspective views of the premolded retainer hinge. 
         FIG. 5  is a perspective view of a honeycomb light louver resting upon an accessory platform. 
         FIG. 6  is a partial perspective view of the fixture with a flexible and expandable opaque cloth light shield applied to the outside panels. 
         FIG. 7  is a perspective view of the front of a fluorescent lighting system in accordance with an alternate embodiment of the invention. 
         FIG. 8  is an exploded view of the premolded outer subpanel U channel, the premolded retainer hinges, the premolded inner subpanel U channel and the premolded central U channel form for the  FIG. 7  embodiment. 
         FIG. 9  is a detailed perspective view of the three U channel forms as used in the  FIG. 7  embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the figures in detail,  FIGS. 1 and 2  are perspective views of the present invention. The invention comprises an elongated corrugated plastic panel  24  made into five subpanels by removing three flutes  17  (only one is shown) of the corrugation out to provide for hinging. The panel  24  includes center panel  12  at the center of said panel, a pair of inner subpanels  11  and  13  each on one side of center subpanel  12 , outer subpanel  10  positioned on the outer side of inner subpanel  11 , and outer subpanel  14  positioned on outer side of inner subpanel  13 . All subpanels  10 ,  11 ,  13  and  14  are symmetrically positioned and longitudinally extending in parallel to center subpanel  12 . Removal of two flutes  17  at each juncture of subpanels  10 / 11  and  13 / 14  provide for convenient and flexible hinging of subpanels without adding extra weight. The center panel may be reflective or an aluminum or other reflective material  21  may be placed under the lamps. 
     In order to prevent the subpanels from reverting back to their original positions after being flexed to a desired configuration, at each end of each outer subpanel  10  and  14 , a premolded U channel  15  in the shape of a rectangle is attached therein so that a one end of a flexible high tension hinge  16  having a substantially rectangular cross section may be easily inserted. The other end of the hinge  16  is inserted into the premolded central U channel  51 . Since hinge  16  is flexible, each subpanel can be manually positioned and held by the hinge in said position. 
     In the preferred embodiment, center subpanel  12  is always twice the width of the outer subpanels  10  and  14 . The fluorescent lighting source  22  is placed on the center subpanel  12 . Inner subpanels  11  and  13  and outer subpanels  10  and  14  are used to control the direction of and limit the output of the fluorescent lighting source  22 . Premolded center U channel  52  includes accessory platform and a ¼ turn lamp harness strain relief socket  53  that secures the lamp harness cord  18 . 
       FIG. 2  is a perspective view of the back of the fixture. A mating plate  43  is centrally located on the back of the fixture. The mating plate interfaces with mounting hardware allowing the fixture to be applied to an industry standard lighting stand. Two fixture strain relief loops  54  consisting of a high tensile strength aircraft wire are located at opposite corners positioned under the mating plate. 
       FIG. 3  is an exploded assembly perspective view of the two premolded U channel openings  58  and  59  and the retainer hinge  16 . The short piston leg  16   a  of the retainer hinge  16  is inserted to receiver channel opening  58  and secured by a fastener pin  55  inserted through a hole  57  on the central U channel  51 . The long piston leg  16   b  is inserted into receiver channel opening  59 . This is done by folding subpanels  10  and  14  back so they are substantially parallel to inner subpanels  11  and  13 . In this position, piston legs  16   a  and  16   b  can be inserted into receiver channels  58  and  59  simultaneously. The removable pin fastener  55  in the central U channel  51  allows for easy removal and replacement of hinge  16  such that in cases of damage or hinge fatigue, resulting in loss of tension, a new hinge can be inserted without having to replace the complete hinging assembly or the lighting system itself. This assembly is mirrored on the remaining four corners of the fixture. Retainer hinge piston  16   b  is inserted into receiver channel  59  on outer subpanel U channel  15 . This assembly is mirrored on the remaining ends of the two outer subpanels  10 . The quarter turn lamp harness strain relief socket  53  is applied to central panel U channel  51 . This central U channel  51  is also applied to the opposite end of the fixture without inclusion of the strain relief socket  53 . 
     The U channels are affixed to their respective subpanels by suitable nuts and bolts, rivets or other fasteners known in the art (not shown in  FIG. 3  but see  FIG. 7  for an embodiment in which barrel nuts and bolts are used). 
     In  FIGS. 4   a - 4   e , a series of perspective and cross sectional views of the retainer hinge  16  having a short piston  16   a  and a long piston  16   b  are shown. The short piston  16   a  has an oblong hole  16   d  for the fastening device. In this manner, slight adjustments can be made to the position of the short piston  16   a  within channel  58  while keeping the short piston within the channel. This movement is necessary to accommodate the off center pivot point of the living hinges  17 . The long piston may also be adjusted within channel  59 , but due to its longer length, a fastening device as used for the short piston is not needed. Both pistons display cross section  16   c  that ensures movement within the channels  59  and  58  with a minimum of friction. 
       FIG. 5  is a perspective view of the honeycomb light louver  61  resting upon the accessory platform  52 . A hook and loop fastener tab  60  is fastened to the frame of the light louver  61 . The fastener tab  60  adheres to its hook and loop opposite  56  that is adhered to the side of the accessory platform  52 . The light louver  61  has the hook and loop attachment mechanism recurrent on the remaining three corners. 
       FIG. 6  is a partial perspective view of the fixture and a flexible and expandable opaque cloth light shield  62  applied to the outside panels. A hook and loop fastener  64  is applied to the outside U channel  15  on both outside panels  10  and  14 . Another hook and loop fastener  65  is applied to the central U channel  51 . The mating hook and loop  63  and  66  is applied to the outside edges of the light shield  62 . The light shield  62  is applied in the same fashion at the other end of the fixture. 
     An alternate embodiment of the invention is illustrated in  FIGS. 7-9 . As shown in  FIG. 7 , instead of central U channel pairs  51 , U channel pairs  71  and  73  may be added to the ends of center panel  12  and inner subpanels  11  and  13 . As compared to the first embodiment shown for example in  FIG. 2 , inner subpanels  11  (not shown in  FIG. 2) and 13  instead of being in a fixed position relative to center panel  12 , in the  FIGS. 7-9  embodiment, inner subpanels  11  and  13  may also be adjusted around a hinge formed between inner panel  11 /center panel  12 , and inner panel  13 /center panel  12 . 
     In particular, in place of central U channel  51 , U channel  73  is attached to each end of center panel  12 . U channel  71  is added to each end of inner subpanel  11  and inner subpanel  13 . U channels  73  and  71  are configured the same as sub channels  51  and  15 . That is, each U channel is placed over an end of its corresponding panel, and a flexible high-tension hinge  16  is inserted into openings in each of the U channels  73  and  71  as described above with respect to the insertion of hinge  16  with reference to  FIG. 3 . Once the U channels and corresponding hinges are installed, the resulting hinges formed between center panel  12 , and inner subpanels  11  and  13  on the one hand, and the hinge formed between each inner and outer subpanel  10 / 11  and  13 / 14  may be adjusted to be in a desired position. The adjustment may be between zero and approximately 90 degrees by the hinges formed between center panel  12 , and inner subpanels  11  and  13 , and between approximately zero degrees and 135 degrees by the hinges found between inner/outer subpanels  10  and  11 , and  13 / 14 . 
     Each of the U channels may be secured by the use of slotted barrel nuts  83  and barrel bolts  85 . In this manner, in addition to securing the U channels to its respective panel, since the barrel nuts and barrel bolts have an open central bore, each nut/bolt pair may be used as a screw point to secure the fixture to a wall when the fixture is used in a studio or on location. The barrel inside diameter should be sufficient to allow, for example, a drywall screw to be inserted so that the panel may be secured to a wall. When such drywall screws are removed, then the fixture may be moved, closed for transport, and be available for subsequent use. Additionally, the barrel nut/bolts allow for easy removal of each of the U channels for replacement or repair of a damaged U channel or hinge. 
     The foregoing description is intended to provide a detailed explanation how to make and use the invention. However, such description is not intended to limit the scope of the invention as defined in the following claims.