Abstract:
An animal cage that holds the cage floor and waste collection assembly in place without the use of mechanical fasteners so that the assembly may be removed for cleaning and replaced by another assembly in minimal time. Also provided is the floor and waste collection assembly that is held in place without the use of mechanical fasteners and is removable for cleaning and replacement by another assembly in minimal time. A quick change electrical connection to provide shock current to the floor of the assembly is accomplished by creating pressure contact between conductive floor bars and electrical contacts of a circuit board in the rear support block of the cage.

Description:
Animal cages have been used for conducting experiments on a wide variety of laboratory organisms including rats, mice, pigeons, squirrel monkeys, and guinea pigs. For this purpose, researchers can select either a test cage specially designed for a particular test animal or a modular cage. In the past, such test cages have included a fixed or removable grid or a wire mesh floor upon which the animal stands as well as a waste collection device located beneath the floor. Also, in the past, some manufacturers of test cages have mounted in a semipermanent way the grid floors to the walls of the cage and positioned the waste collection device below the grid floor. Thus, in some past test cages, the floor and waste collection assembly has been an integral part of the cage. In other previous test cages, the floor and waste collection assembly has been removable as a separate element. Moreover, even in past cages with removable assemblies and with floor bars that allowed electrical shocking of the test animal, a researcher could not simply detach the assembly from the cage. This was so because the floor bars of past assemblies were connected to an electric shocking apparatus in such a manner so that each electrical connection had to be first disconnected from each floor bar before removal and replacement of the grid floor for cleaning and sanitation. 
     In conducting animal experiments, it is often required that the scent and all other traces of a test animal be removed prior to the entry of a subsequent test animal into the cage. Regardless of what kind of test cage is used, to de-scent and/or sanitize a cage, a researcher must remove the floor and/or the waste collection device, clean them and replace them with a cleaned set. In the past, sanitizing a cage demanded replacement of two separate movable parts. Specifically, the sanitation of past cages has been cumbersome and time-consuming because the floor and the waste collection device have had to be disconnected from each other, removed, cleaned and then reattached before insertion into the cage. 
     Moreover, in conducting animal experiments, it is often needed to deliver an electrical shock to the feet of the test animal. For this purpose the grid or mesh floors of past test cages have been adapted to conduct electricity by directly connecting an electrical contact to each floor bar. Therefore, replacing a soiled floor and waste collection assembly in the past has required disconnection of each individual hard wired contact to each floor bar followed by re-attachment of each contact to the cleaned floor bars. 
     The following United States patents may be of interest to provide background to past test cages: 
     U.S. Pat. No. 2,796,044 issued to Breland; U.S. Pat. No. 3,234,907 issued to Palencia; U.S. Pat. No. 3,297,907 issued to Evans; U.S. Pat. No. 3,397,676 issued to Barney; U.S. Pat. No. 3,429,297 issued to Schroer; U.S. Pat. No. 3,467,064 issued to Glass, et. al.; U.S. Pat. No. 3,516,389 issued to Meyer; U.S. Pat. No. 3,540,413 issued to Castaigne; U.S. Pat. No. 3,602,195 issued to Blough; U.S. Pat. No. 3,467,064 issued to Bailey, et. al.; U.S. Pat. No. 3,626,902 issued to Orfei; U.S. Pat. No. 3,693,590 issued to Bowers; U.S. Pat. No. 3,698,360 issued to Rubricius; U.S. Pat. No. 3,830,201 issued to Coulbourn; U.S. Pat. No. 4,651,675 issued to Collier; U.S. Pat. No. 4869,206 issued to Spina. 
     Before now, test cages and floor waste collection assemblies that allow quick removal and replacement for cleaning have not been available. Moreover, test cages and floor-waste collection assemblies that allow a researcher to carry out shock and non-shock experiments as needed have also not been available before now. 
     The present invention provides a test cage that allows a researcher to quickly change the floor and waste collection assembly and to conduct both shock and non-shock experiments as needed without having to disconnect the electrical connections or alter the structural integrity of the cage. In addition, the present invention also provides a quick change floor and waste collection assembly used in a test cage, which assembly allows a researcher to quickly change the floor and waste collection assembly and to conduct both shock and non-shock experiments as needed without having to alter the electrical connections between the floor and the cage or the structural integrity of the cage. The present invention also provides a method of conducting animal experimentation and for cleaning test cages without altering electrical connections between the floor and the cage or the structural integrity of the cage. 
     By re-designing the floor and waste collection assembly as well as the structural relationship between the assembly and the cage, the present invention offers an efficient research chamber. The cage and assembly of the present invention may be used with a variety of test animals, and for both shock and non-shock experiments without having to alter electrical connections between the floor and the cage or the structural integrity of the cage. With the present invention, a user may quickly remove from a test cage the scent and waste traces of the previous animal prior to introducing the next animal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates an embodiment of the quick change test cage of the present invention. 
     FIG. 2 illustrates an embodiment of the quick change floor and waste collection assembly of the present invention, showing an exploded view of the locking and guide hardware. 
     FIG. 3 shows an exploded view of the waste pan hardware and the contact block of the embodiment of shown in FIG.  2 . 
     FIG. 4 is a plan view of an embodiment of the assembly of the present invention looking down from the top of the test cage. 
     FIG. 5 illustrates in perspective an embodiment of the assembly of the present invention, showing an exploded view of the hardware residing in and connected to the contact block as well as the relationship of the floor to the rear floor support and to the contact block. 
     FIG. 6A shows in detail the relationship of the rear floor support of one embodiment of the assembly to the contact block. 
     FIG. 6B details the articulation and insertion of the assembly into the contact block. 
     FIG. 7 shows an alternative embodiment of the cage of the present invention, showing a mesh floor. 
     FIG. 8 shows an assembly of the alternative embodiment illustrated in FIG. 7, depicting an exploded view of the hardware residing in and connected to the contact block as well as the relationship of the floor to the rear floor support and to the contact block. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows an embodiment of a test cage  10  of the present invention. Cage  10  comprises a cage frame  2  and a quick change floor and waste collection assembly  4 . The cage frame  2  comprises a cage roof  40 , a cage base  34 , corner supports  36 , side supports  38 , front, back and side walls  52 , a front lock bar  12  and guide strips  18 . The cage roof  40  and cage base  34  are secured in a semipermanent manner, such as by bolt, screw, or the like, to corner supports  36  and to side supports  38 . 
     With continuing reference to FIG. 1, FIGS. 2 and 3 show an embodiment of quick change floor and waste collection assembly  4  of the present invention. This embodiment is adapted to allow both shock and non-shock experimentation as needed. It comprises the floor elements  14 ,  16 ,  20 ,  22 ,  26  and the waste pan  28 . The entire quick floor and collection assembly  4  glides between corner supports  36  and side supports  38  along guide strips  18 . These are attached by bolt, screw or the like to the inner surface of corner supports  36 , as shown in FIG.  1 . Guide strips  18  facilitate insertion of assembly  4  into cage  10  by providing a continuous surface along which rear floor support  26  and waste pan  28  glides. Guide strips  18  also prevent side supports  38  from hindering the action of pushing rear floor support  26  next to contact block  24 . As shown in FIGS. 2 and 3, an embodiment of the quick change floor comprises a nonconductive front floor support  20 , a nonconductive rear floor support  26  and a plurality of electrically conductive floor bars  22 . The floor bars  22  are attached in a permanent manner, such as by press fit, an adhesive bond or the like, to front floor support  20  and rear floor support  26 . 
     Two waste pan supports  14  are attached, one to front floor support  20  and the second to rear floor support  26  in a permanent manner. As shown in FIG. 3, the waste pan  28  is situated between the front  20  and the rear  26  floor supports. A single bolt, screw or the like, its position indicated by B in FIG. 3, attaches the waste pan to front floor support  20 . After removal of B, the waste pan is free to slide to either side for easy detachment from the floor subassembly. Thus, the waste pan may be removed for separate cleaning during experimentation, if needed. Alternatively, it may remain attached to the assembly during experimentation, and be removed from the cage with the entire assembly. After the assembly is removed, the waste pan may then be detached and cleaned separately or remain attached and be cleaned with the entire assembly. Detachability of the waste pan allows the researcher flexibility to use a variety of cleaning and de-scenting approaches. 
     Front lock bar  12 , especially as shown in FIG. 1, is permanently attached to cage base  34  and is constructed of a rigid material. Front lock bar  12  provides a locking-in mechanism for the floor and waste collection assembly  4  and prevents forward movement of the assembly when the assembly is properly inserted and positioned in cage  10 . As FIGS. 1 and 2 show, a handle  16  which is permanently attached to front floor support  20 , facilitates lifting front floor support  20  up and over front lock bar  12 . As shown especially in FIG. 2, the guide strips  18  prevent longitudinal movement of assembly  4  when it is positioned in cage  10 . 
     As shown in FIGS. 1 and 2, contact block  24 , which is attached to cage base  34  in a semipermanent manner, such as by bolt, screw or the like, prevents backward movement of the assembly  4 . As FIG. 5 shows, contact block  24  comprises a plurality of holes  50 , a matching plurality of contact pins  42  and contact springs  30 . FIGS. 5 and 6A show that situated within each hole  50  is a contact spring  30 , which houses a contact pin  42 . In embodiments of the floor and waste collection assembly suitable for both shock and non-shock experiments, the contact pins  42  and springs  30  comprise a conductive material. 
     FIG. 5 shows contact plate  32  attached in a semipermanent manner to the outer surface of contact block  24 . In embodiments of the assembly suitable for both shock and non-shock experiments, the contact plate  32  comprises a circuit board, with contact points that correspond to the location of the holes  50  in contact block  24 . Other embodiments where electrical conductivity must be kept to an absolute minimum do not comprise a circuit board and contact plate  32  comprises a material suitable for minimizing electro-conductivity. 
     Referring now to FIG. 6A, each contact hole  50  traverses completely through contact block  24 . Each contact hole  50  has a bipartite diameter. The front cavity  48  of each hole  50  is cut so as to snugly receive the extension of the floor bar  22  that extends past rear floor support  26 . The rear cavity  46  of each hole  50  is cut to accommodate the diameter of the head of contact pin  24 . Thus, as FIGS. 5 and 6 show, a contact pin  42  is inserted into each contact hole  50  from the rear side of contact block  24 . Once the pin  42  is inserted, a contact spring  30  is then inserted into each contact hole  50  from the rear side. The diameter of the contact spring  30  is smaller than the head of the contact pin  24 . In this way, as FIG. 6A shows, a contact spring  30  surrounds and houses a contact pin  42  in each rear cavity  46 , but cannot pass over the head of the contact pin  42 . Moreover, the head of each contact pin is larger than the aperture to the front cavity  48 . This insures the following: that the contact pin  42  does not enter front cavity  48  and that the floor bar  22 , when properly inserted into the contact block, pushes on the spring-pin combination  42 - 30  and causes the combination to make proper and continuous contact with the contact plate 
     With continuing reference to FIGS. 4 and 7, FIGS. 6A and B illustrate that, upon inserting the quick change floor and waste collection assembly  4  into cage  10  the extensions of the floor bars  22  enter the front cavity  48  in contact block  24 . Floor bars  22  exert continuous pressure on the spring-pin  30 - 42  combination and cause the spring to coil within rear cavity  46 . As the ends of floor bars  22  are positioned to fit snugly into contact holes  50 , the front of the assembly  4  is drawn past the front lock bar  12 . It is only when the front of the assembly clears the front lock bar  12  that the front of the assembly drops down into a locked-in position behind front lock bar  12 . See FIG.  1 . 
     Proper positioning of the quick change floor and waste collection assembly of the present invention creates continuous tension between front floor support  20  and contact block  24 , which provides a locking-in mechanism that prevents the assembly from popping out of the cage while one or more test animals are using it. Moreover, in the embodiment of the assembly that comprises a circuit board in contact plate  32  and electrically conductive floor bars  22 , the locking-in mechanism and continuous tension keep the contact springs  30  taut and in contact with the contact points of circuit board of contact plate  32 . This in turn maintains the integrity of the cage and assembly as an electro-conductive circuit and allows shock experimentation to be conducted at will, on an as needed basis. 
     The results of creating an electro-conductive circuit by continuous, locking-in tension when a quick-clean floor and waste assembly is inserted into the cage are twofold. First, the cage or assembly of the present invention allows a researcher to conduct shock or non-shock experiments on test animals housed therein. At the same time, the present invention provides a way to quickly remove the traces of the previous test animal from the cage by simply pulling the used, soiled assembly out of the cage and inserting a fresh, cleaned one. In this way, the present invention allows a researcher to almost instantaneously de-scent and sanitize a test animal chamber and change the test animal housed therein to begin a new research protocol. 
     FIG. 7 shows an alternative embodiment wherein quick change floor and waste collection assembly  5  comprises a floor constructed of mesh  23 , supported at the ends and in the middle by floor bars  22 . Depending on research needs, the mesh of floor  23  could be metal or alternatively plastic, nylon, rubber, or other electrically non-conductive materials. The mesh of floor  23  must be sufficiently tightly woven and of sufficient rigidity and durability so that the mesh does not warp or tear and supports the animal&#39;s weight during experimentation. In the embodiment of assembly  5 , suitable for conducting both shock and non-shock experimentation, the mesh floor  23  would end at rear floor support  27 . The floor bars  22  extend through rear floor support  27  and make contact with contact block  25  in a manner similar to the previously described embodiment that comprised a floor of grid bars. In the mesh floor embodiment, the number of bars may be considerably reduced, being used solely to support the mesh and to create the electrical connection between the circuit board of contact plate  32  and the mesh floor  23 . 
     As described above, certain embodiments of the present invention comprise elements of conductive material as well as a circuit board, thereby permitting shock and non-shock tests to be conducted, as needed. Alternatively, a wholly non-conductive embodiment of the present invention may be constructed to accommodate those research situations in which electromagnetic radiation to the test animal is kept to a minimum, such as when the experiment demands measuring the animal&#39;s own radiation. For example, referring to FIG. 2, the waste pan supports  14 , the front handle  16 , the guide rails  18 , and the waste pan  28  may be constructed of plastic, rubber or any other suitable electrically non-conductive material. Front floor support  20 , rear floor support  26  or  27  and contact block  24  or  25  may be constructed of wood, laminated wood or a composite wood product, such as pressboard. In the non-conductive embodiment, the contact plate would not comprise a circuit board. Further, contact springs  30  and contact pins  42  may be of plastic or other suitable material. The floor bars  22  in FIGS. 1-4,  8  may be glass, acrylic or other plastic that are designed and constructed to accommodate the weight of the largest animal or the greatest number of animals housed in the cage together. 
     With any of these embodiments, the size of the cage or concomitantly the size of the quick change floor and waste collection assembly is not a limiting factor to the usefulness of the present invention. The cage, as well as the floor and waste collection assembly, of the present invention is effective in any size suitable for a wide range of test animals, from the small, such as mice and other rodents, to the great, such as chimpanzees and large dogs. The more important consideration is to ensure that the quick change floor and waste collection assembly is sized to the cage in which it is used so that there is a continuous, sufficient tension that locks the assembly into position. 
     Insertion, Removal and Cleaning of Floor and Waste Pan 
     Referring to FIG.  1  and FIG. 7, a user inserts the quick change floor and waste pan assembly  4  or  5  by gliding the assembly along guide rails  18  until the extending portions of the floor bars  22  fit snugly into contact holes  50  in the contact block  24  or  25 . The extending portions of the floor bars  22  continuously press on contact springs  30  residing in the rear cavity  46  of contact holes  50  when the assembly is properly positioned. A user has properly positioned the rear surface of the assembly into the contact block when the front floor support  20  clears the front lock bar  12  and drops down into a locked position behind it. 
     To remove the assembly, a user, grasping the front handle  16 , pulls up on the front section of the assembly to clear the front lock bar  12  and then slides the assembly out of the cage. At this point, the researcher may place the entire assembly into a mechanized cleaning apparatus known in the art, whereby the assembly is cleaned using a known industrial method, which removes scent traces of the previous test animal and sanitizes the assembly. Of course, hand cleaning of the assembly is an alternative. 
     A researcher may remove the waste pan to empty it before cleaning the assembly. Referring to FIG. 3, a user disengages the waste pan  22  from the assembly by removing the single screw, bolt or the like as indicated by B, which connects the front waste pan support  14  to the waste pan. The waste pan may then be slid out laterally from the assembly. 
     A research can create a quick change test chamber by having more than one assembly on hand. In this way, a researcher can remove a soiled assembly and insert a clean one, thereby allowing an almost instantaneous change of the test animal in the test chamber. During the experimentation, by causing the soiled assembly to be cleaned, the researcher ensures a quick change of the assembly when needed. 
     Moreover, a researcher may practice a method of quickly changing a test animal in several ways. A researcher may use the cage of the present invention, which includes those elements of the cage structure that position the floor and waste collection assembly into the cage, namely, the front lock bar and the contact block, along with the removable, disconnectable floor and waste collection assembly. Alternatively, a researcher may use the floor and waste collection assembly of the present invention with other cages, be they fixed or modular, simply by modifying the cage to include a front lock bar and a contact block so that a floor and waste collection assembly of the present invention inserts into the contact block causing the floor bars of the assembly to create a contact with the contact plate when the front of the assembly is positioned behind the front lock bar. 
     Since the invention may undergo structural changes and experience various applications of use within its scope, this description is not intended to limit the invention to the disclosed forms but to cover those modifications, changes, alternative constructions and methods falling with the scope of the principle taught here.