Abstract:
A system and method for illuminating individual animal cages secured in a multiple cage rack is described. A first lighting system makes use of LEDs secured on the frame of a multiple cage rack; or attached to or disposed in each individual cage. A second lighting system utilizes fiber optic cables connected to or adjacent each individual cage or disposed within. Clear observation of all animals at will is economically provided without interference with normal cleaning and sterilizing procedures, utilizing the virtually maintenance free lighting system.

Description:
FIELD OF THE INVENTION 
   This application claims the benefit of U.S. Provisional Application No. 60/368,110, filed Mar. 27, 2002. This invention relates to multiple cage systems for housing animals primarily for experimental purposes, and in particular to a system and method for lighting the cages for convenient viewing of the animals contained therein. 

   BACKGROUND OF THE INVENTION 
   In current medical research animals to be experimented upon, such as, for example, mice, rats, and guinea pigs, are housed in cages. The cages are often of the same size for convenience in stacking one upon another for placement within a central rack and cage support arrangement. Since medical research demands fairly large numbers of experimental data to be statistically significant, the number of animals and hence cages is also necessarily relatively large. Means are, of course, provided for adequate water supply and food for each animal, and access to each animal where required. However, often ambient room lighting is the only source of illumination for the cages themselves. Technicians may resort to the use of a flashlight, which is somewhat inconvenient and not always available. This may necessitate removing or opening each cage and manually handling the research animal, a time consuming and potentially hazardous procedure. Research data can also be skewed. The present invention addresses these problems, providing clear illumination of the animal(s) housed in each cage in an efficient and economical manner. 
   Some Objects of the Present Invention 
   It is therefore a primary object of the invention to provide clear illumination for animals housed in multiple cages. 
   A further object of the invention is to provide lighting directed to individual cages. 
   Still another object of the invention is to provide lighting of different colors to individual cages. 
   Yet another object of the invention is to provide lighting of different intensities to individual cages. 
   An additional object of the invention is to provide a light source for illuminating animal cages that can be easily removed, or left in place when the rack and cage support system is cleaned and/or sterilized, without danger to the lighting system. 
   Yet another additional object of one embodiment of the invention is to provide lighting utilizing LED or fiber optic devices which is easily moved and positioned within the rack area and where the LED or fiber optic devices remain positioned on the frame. 
   A still further additional object of another embodiment of the invention would be to provide lighting by mounting individual LEDs or fiber optic devices in each animal cage which are powered through an electrical receptacle or coupled to an external fiber optic device which would engage a plug portion in the cage to energize the LED or fiber optic device when the cage slides into a frame position. 
   These and other objects are obtained with the animal cage lighting system and method of the present invention. 
   In the housing of experimental laboratory animals a great deal of effort and ingenuity has been employed for caring for these animals, and the necessary cleaning procedures for the multiple cages. Surprisingly, little thought has been given to adequately lighting the individual cages. As noted above, technicians must often resort to flashlights or physically handle the cages and animals with potential danger to themselves or risk of skewing research data. 
   SUMMARY OF THE INVENTION 
   Towards the accomplishment of the above, a system for illuminating the interior of each of a plurality of animal cages to be positioned on a rack and cage arrangement wherein the rack has at least one cage arrangement. The arrangement includes a plurality of respective animal cage positions. A given system comprises a source of energy, i.e. either electrical energy or light energy. Means are provided to cooperatively engage the source of energy employed to thereby provide at least one respective portion of either the electrical energy or light energy and for transporting the energy (electrical conductors or fiber optic devices or cable) to respective predetermined locations in the rack and cage arrangement. 
   If electrical energy is transported, means such as LED devices for converting the transported electrical energy into respective portions of light energy are employed. The respective predetermined locations in the rack and cage arrangement correspond in number, at least, to the number of animal cages to be illumined. Each of the respective portions of light energy when located at a respective predetermined location in the cage and rack arrangement are suitable for illuminating the interior of a respective one of the animal cages when the respective one of the animal cages is in place in its respective position in the arrangement. 
   In a given system the source of energy can be detachably affixed to the rack and cage arrangement, so that it can be removed prior to when the rack and cage arrangement is to be cleaned or autoclaved. 
   In a given system the means for transporting and means for converting, for example, the LED devices, if required, can remain in place on the rack and cage arrangement when the rack and cage arrangement is to be cleaned and/or autoclaved. 
   One particular rack and cage arrangement which is improved by the present invention, includes a plurality of vertical cage arrangements juxtaposed one to the other such that a grid-like arrangement of animal cage positions results. Each animal cage position extends generally, longitudinally from a front plane to a rear plane; and extends generally, laterally from a first side plane to a second side plane. The respective predetermined locations where the light energy emanates are located generally at at least one of the intersections of the rear plane and side planes. 
   In another embodiment employing the teachings of the present invention, the respective predetermined locations where the light energy emanates are located generally in the rear plane, behind the respective animal cage when it is in its respective position. 
   In yet another embodiment employing the teachings of the present invention the respective predetermined locations where the light energy emanates are located generally in at least one of the side planes. 
   In a further embodiment, means for emitting light energy are disposed within each of the animal cages to be illuminated. In this embodiment, the respective portions of either the electrical energy or the light energy at the respective predetermined locations in the rack and cage arrangement, are coupled to the means for emitting light energy within each cage. In this embodiment, the means for emitting light energy could be an LED or fiber optic device. 
   Two systems for illuminating multiple animal cages are envisioned in the present invention. In the first system of the invention light emitting diodes or LED&#39;s are employed. LED&#39;s offer numerous advantages for this application. They can, for example, be battery operated systems; or powered by an ac to dc converter connected to a standard 120 volt electric outlet. The electrical source can be mounted and built in many variations to fit the requirements of various users. The LED light source (bar, strip, fixture, single LED) can be made in many variations of shape, size, intensity, color, and wiring method. For example, the electric wires can be external to the cage frame, inside the cage frame members, or a combination of both. The wiring can be a 2 wire or a 1 wire frame grounded as in a car system. As will be more fully explained, numerous advantages can be provided by an LED lighting system for each cage, including: the light color can be changed and/or varied (red LEDs can be employed, for example, which will allow “visibility” without disturbing the animals as may occur with “white” light); light can be directed to just the cage area, or more generally; the light source can be removed, or light system designed to withstand cleaning or sterilization to the cage shelf/rack unit without damage. 
   In the second adaptation of the present invention individual cage lighting is provided by fiber optic cables. A light source produces light which is directed into one end of the fiber optic cables which could be glass, plastic or other suitable material depending on requirements for cleaning, for example, temperature. As will be more fully explained, when positioned on multiple cage systems the fiber optic cable can snake through the shelf/rack framing until the area where the light is needed is reached. Light comes out of the end of the fiber optic cable and is directed where it is needed either directly or through a light distribution emitter or bar. Alternatively, fiber optic cables which emit light along their entire length can be employed when more general lighting is desired. 
   Still further, the cable can be cut and a diverter inserted. This will allow for the redirection of a percentage of the light as may be required. 
   A filter can be inserted in one or more cable lines or at the light source to reduce the intensity of the light if that is preferred or provide different colors. 
   Similar to the above described LED lighting system, fiber optic lighting sources can be mounted in various locations, not just on the top of the cage rack. This system can be remote or built-into other systems on the cage rack housing unit. Again, similar to LED&#39;s, fiber optic cables can be mounted external to cage framing, inside the frame members, or a combination of both. The fiber optic cables themselves can be single thin fiber, multiple fiber bundles, a single thick fiber, a fiber that conveys light without light lost to sides, a fiber that projects light along its sides, and a light fiber with “T&#39;s” to split light from its main runner off to branches. Advantages of fiber optic lighting again are similar to those of LED&#39;s, including: lighting integral to animal housing rack or shelf; lighting is directed to individual cages; lighting can be provided in different colors; lighting can be provided in different intensities; light source can be removed and the cage/rack unit washed and/or sterilized with light fibers and light emitters in place without damaging the lighting system. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a rack and cage arrangement with animal cages in position. 
       FIG. 2  is an exploded schematic view of a vertical column of cages showing one embodiment implementing the principles of the invention. 
       FIG. 3  is a perspective view of a rack and cage arrangement with cages similar to  FIG. 1 , illustrating yet another embodiment of the present invention. 
       FIG. 4  is an exploded schematic view of a vertical column of cages showing still another embodiment of the present invention. 
       FIG. 5  is a perspective view of a tray which supports a cage, showing an adaptation of the embodiment of  FIG. 4 . 
       FIGS. 6 and 7  are schematic views similar to  FIG. 4  showing alternative fiber optic individual cage lighting systems comprising a single fiber optic cable. 
       FIG. 8  depicts an alternative arrangement to that disclosed in  FIGS. 6 and 7  using a single fiber optic cable. 
       FIG. 9  depicts yet another embodiment implementing the principles of the present invention. 
       FIGS. 10 and 11  depict embodiments employing principles of the present invention where the means for emitting light energy are disposed within each of the animal cages. 
   

   DETAILED DESCRIPTION 
   Turning now to the drawings in which similar structures having the same function are denoted with the same numerals, in  FIG. 1  a typical rack and cage arrangement  10  for housing laboratory animals is shown. Animal cages  12  are stacked in vertical cage arrangements, in respective cage positions. 
   In  FIG. 2 , a source of DC electrical energy, converter power supply,  14  is connected to a source of AC power, 120/220v, 50/60 HZ at outlet  16 . 
   A single or multiple lead cable  18  cooperatively engages the power supply  14  through an appropriate connector  20 . The cable  18  conducts the electrical energy provided by the power supply to respective predetermined locations, for example,  22 ,  24 ,  26 ,  28 , and  30 , throughout the rack and cage arrangement  10 . 
   At each predetermined location, a device to convert the electrical energy into light energy is appropriately positioned to illuminate the interior of the animal cage in place on its corresponding location. In  FIG. 2  such devices for converting electrical energy are shown as a series of LED strips,  32 ,  34 ,  36 ,  38 , and  40 . 
   In  FIG. 2  these strips are shown, for illustration purposes, to vary in length although of course, they might be of the same length or of different configuration. Such devices are available from numerous suppliers including LEDTRONICS, INC. in Torrance, Calif. 
   The LED strips typically would be secured at each location to the rack frame (not shown for clarity purposes). Although positioned in  FIG. 2  in the plane separating two juxtaposed, vertical cage arrangements, it should be apparent that the Led devices could be positioned at other locations depending on the user&#39;s needs and the particular rack configuration. So for example, the LED devices could be positioned in a plane at the rear  42  of the cage position at respective positions such that they could illumine the interior of an associated animal cage. Of course, such devices could be positioned in both side planes, each directed towards the same animal cage, as well as other appropriate locations. 
   Although a power pack is described as a source of electrical energy, alternative sources of energy suitable for such devices, for example, batteries, can also be employed. 
   The LED devices and routing cable  18  that are employed can be selected for their imperviousness to the anticipated cleaning environment, including sterilization procedures such as autoclaving. By simply removing the power supply  14 , if physically affixed to the rack and cage arrangement, the activity of cleaning and/or sterilizing is facilitated. 
   The LED strips can include LEDs of different color as may be dictated by the physiological sensitivities of the research animal. So for example, alternating white and red LED lamps in a single strip may be of an advantage where the research animals are mice. Whatever the need, LED devices as applied herein employing the principles of the invention, provide a great degree of flexibility in illuminating the subject creatures heretofore not experienced in this field. 
     FIG. 3  illustrates another embodiment of the illuminating system of the present invention. A rack and cage arrangement  10  is shown including a plurality of animal cages  12  disposed in respective positions in juxtaposed vertical cage arrangements  44 . 
   Detachably affixed to the top of the rack and this cage arrangement is a source of light energy, light generator  46 . These generators, available typically as halogen or metal halide units are provided in various wattages, for example in the range of 10 to 250 watts. A suitable generator for this application is available through VISUAL LIGHTING TECHNOLOGIES located in Mission Viejo. Calif. 
   In  FIG. 4 , a coupling device  48  cooperatively engages the source  46  to thereby provide access to the bundle of strands  50  of optical fiber and to channel light energy thereto in accordance with known techniques. The individual fiber strands in the bundle  50  transport its respective proportion of light energy to respective predetermined locations, for example,  52 ,  54 ,  56 ,  58 , and  60  in the rack and cage arrangement. 
   At the terminus of respective cables, at the predetermined locations, such as  52 ,  54 ,  56 ,  58 , and  60  suitable light fittings  62 ,  64 ,  66 ,  68 , and  70  are employed to illuminate the interior of a respective animal cage in place in its respective position. As illustrated the light fittings are positioned in a side plane adjacent to the animal cage cubicle. The light fittings would be secured to the rack in an appropriate fashion, not shown for clarity purposes. As with the embodiment employing LEDs, it should be apparent that the flexibility afforded by the ability to route the fiber optic cable as the user deems necessary, the fiber optic light fittings could be positioned at other locations. So for example they could be positioned in a plane  72  at the rear of the cage arrangement, at respective positions such that they could illuminate the interior of an associated animal cage. Still further, as above, such light fittings could be positioned in both side planes, each directed towards the same animal cage, as well as other appropriate locations identifiable by the end user. 
   Although the embodiment is described as employing light fittings for directing the light energy at the terminus of each cable, fiber optic technology offers various other techniques for exposing and directing the light energy, readily apparent, which can implement the purposes of the invention. 
   The fiber optic cable and light fittings and coupling device,  48 , can be selected for their imperviousness to the anticipated cleaning environment, including sterilization procedures such as autoclaving. 
   In  FIG. 5 , the inventors illustrate one approach, using fiber optic cables  74  and  76 , for illuminating, from both sides an animal cage in position. The cage, not shown, when positioned in the rack and cage arrangement would rest on surface  78  of saddle  80 . The saddle includes upwardly expending side members  82  and  84 . These side members are formed having respective channels  86 ,  88  into which the termini of cables  74  and  76  are positioned and secured in an acceptable way. The inwardly positioned sides of the channels include slotted openings, for example,  90  and  92 , through which light energy is directed so as to illuminate the interior of the animal cage when it is in place. 
   As with the LED devices, the color of the illuminating light energy can be altered by suitable filters at the light source, or at individual predetermined locations using suitable light fittings. 
   Also attenuators and other known techniques can be employed to alter the intensity of the emitting light as may be required. 
     FIGS. 6 and 7  depict applications employing principles of the present invention where solid core, fiber optics devices may be employed. 
   In  FIG. 6 , a rectangular fiber optic device or cable  94  is shown coupled through a suitable coupling to light source  96 . For the application shown the rectangular cable is disposed along the top of a rack and cage arrangement such as depicted in  FIG. 3 . At the juxtaposition of adjacent vertical cage arrangements such as  98 , a vertically descending fiber optic cable  100  is “T” coupled in a known way at  102  to the horizontally disposed cable  94 . Cable  100  is shown positioned at the rear corner where a side plane and rear plane defining the cage positions would intersect. If the purpose of the cable  100  is to provide light energy at the locations in the rack and cage arrangement where the individual cages are to be positioned, and not generally lighting, optimally cables  94  and  100  would be clad, except for the specific locations where light energy is to be emitted, for example  104 ,  106 ,  108 ,  110 , and 112. These locations can be bared on those sides where the user decides it is important to direct the emitted light energy. As illustrated this would be on three sides, including the side immediately adjacent the animal cages depicted. 
   A further vertically descending cable,  114  is positioned in the other rear corner for similar purposes. 
     FIG. 7  illustrates an alternate application where a vertically descending solid core, fiber optic cable is employed. Here a cable  116  descends from a “T” coupling with horizontally disposed cable  118 . Cable  116  descends in a plane to the rear  120  of the cages when in position. If it is the user&#39;s intention, the cable  116  can be clad except at the location where each cage is positioned, where it is removed to allow light to emit so as to illuminate the interior of the cage. In current rack and cage arrangements, back to back systems are employed so that removal of the clad on the opposite face of the cable  116  would allow illumination of the interior of the cages in the rear rack and cage system. 
   Cable  122  cooperates in a similar fashion with the vertical cage arrangement (not shown) juxtaposed with the one illustrated. 
     FIG. 8  is an alternate enablement of the embodiment of  FIG. 6 . Here individual fiber optic cables  124  and  126  are coupled to light source  128 . Again as illustrated the light source  128  and the first run of cables  124  and  126  are horizontally disposed. Cable  124  is sufficiently pliable to permit a flexing at point  130  where the cable descends in a vertical fashion similar to cable  100  in  FIG. 6 . The cable is positioned in relation to the rack and cage arrangement as was described with respect to  FIG. 6 . Windows in the cable&#39;s clad covering  132 ,  134 ,  136 ,  138 , and  140  function identically to locations  104 – 112  described above. 
   Cable  126  extends outwardly further from light source  128  before it descends vertically after bending at  142 . As with cable  114 , it would be positioned in the right rear corner of the immediately adjacent vertical cage arrangement, not shown. 
   Similarly the adaptation of  FIG. 8  can allow for positioning of the vertically descending cables to the rear of the cage positions as explained above in relation to  FIG. 7 . 
     FIG. 9  depicts still another embodiment of the principles of the present invention. Here a flexible fiber optic cable  144  is coupled to light source  146 . The source  146  can be positioned on the top of the rack. The cable  144  emanates from the source initially in a horizontal direction and then follows a serpentine path as it traverses behind (in this depiction) each of the cages positioned the rack and cage arrangement shown. The flexible cable can be shorn of all cladding such that it can provide a back-drop curtain of light; or have the cladding removed at specific locations, for example, behind each cage or cages if a back to back rack system is involved. 
   Generally the LED configuration more specifically described above with respect to  FIGS. 1 and 2 , could also be employed in the serpentine layout depicted in  FIG. 9 , with the LED devices positioned where the needs of the user dictate. 
     FIGS. 10 and 11  depict still another adaptation of the principles of the present invention. In  FIG. 10 , the bottom portion  148  of a typical animal cage is shown supported on a shelf plate  150 . A cable  152  carrying electric energy from a power source such as  14  in  FIG. 2  is brought to a predetermined location typically at the rear  154  of a cage cubicle. The cable  152  is terminated in a suitable connector  156  which is rigidly secured by bracket  158  or the like to the rack structure, not shown. 
   The cage bottom  148  includes a coupling connector  160  which is secured to the rear wall  162 . Electrically connected to connector  160  is a light emitting device such as LED  164 , which is also physically restrained in a set position. When the cage including bottom portion  148  is positioned in its cubicle in the rack and cage arrangement, the position of the connector portions  156  and  160  are aligned and axially restrained so that a secure electrical connection can be made. Now when electric energy is supplied to cable  152 , the emitting device  164  will light and illuminate the cage. 
   In  FIG. 11  the principle is the same except a fiber optic system is depicted. Here a fiber optic cable  164  is brought to the predetermined location, behind a particular cage cubicle. The cable  164  terminates in a suitable coupling  166  which is secured to the rack frame, not shown, by bracket  168 . Cage bottom  170  includes a fiber optic mating coupling  172  for coupling  166 . Coupling  172  is secured to the side wall  174  of the cage bottom  170 . Coupled to coupling  172  is a suitable fiber optic light fitting  176 . When the cage including bottom portion  170  is positioned in its cubicle in the rack and cage arrangement, the position of the connector portions  166  and  172  are aligned and axially restrained so that a secure coupling is provided so as to minimize the loss of light energy. Now when the light source such as  46  in  FIG. 3  is energized, the light fitting  176  will emit light energy as dictated by its characteristics. 
   Many other changes could be made to the invention and its numerous embodiments described above without departing from the spirit thereof. The flexibility of the LED wiring or fiber optic cable systems described herein and the devices themselves, permit almost an infinite number of strategies for lighting up the rack and cage arrangements used for animal research. The versatility shown will permit readjustments as necessary to optimize the characteristics of a given system. 
   The potential for such changes within the breadth of the invention will only be limited by the scope of the appended claims.