Abstract:
A test tube rack for supporting, storing and carrying a plurality of test tubes in a laboratory environment comprising a tray, a central support panel and/or lower support panel and a cover. The tray and cover are identical and interchangeable, and tapered for storage in nested stacks. Wells in the tray bottom are in alignment with corresponding openings in the central support panel and corresponding holes in the lower support panel and with domes in the cover, and serve to locate and retain test tubes within the test tube rack. The cover snap-attaches to the tray by means of at least one molded-in tab on the tray or cover which is received and frictionally retained by a corresponding well on the opposite element, thereby locating and securing the cover to the tray, and also locating and securing the central support panel between the tray and the cover. A dual-purpose support panel has manually removable perforated edges allowing it to serve either as a central support panel or, with the perforated edges removed, as a lower support panel. The test tube rack is preferably made of transparent injection-molded or thermoformed plastic.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to improvements in an inexpensive disposable test tube rack suitable for safely storing and carrying a plurality of test tubes, or other axially elongated articles, in supported, separated, upstanding relationship to each other.  
       BACKGROUND OF THE INVENTION  
       [0002]     In a laboratory environment, particularly in laboratories working with biologically active materials, it is important to have a secure means of supporting an array of test tubes, often in a predetermined order, and of transporting and storing them between uses. Among the desirable features in such a product are: transparency, so that the test tubes and their contents are readily visible; nestability, so that the parts of the test tube rack may be compactly nested when not in use; stackability, so that assembled test tube racks may be stacked one on top of the other for storage; and disposability, so that a rack containing a group of used test tubes may be disposed of as a unit, thereby avoiding the need to remove the tubes individually and the need to clean and sterilize the test tube rack for re-use.  
         [0003]     To accomplish at least some of the above purposes, a number of devices are disclosed by the prior art, including the following.  
         [0004]     Delair U.S. Pat. No. 3,184,071 (May 18, 1965) discloses an injection-molded plastic case for various kinds of containers, including glass containers, in which the principal embodiment has both a central perforated rack and a similarly perforated cover to give two levels of support to hold the containers in an upright position.  
         [0005]     Mander, et al. U.S. Pat. No. 3,643,812 (Feb. 22, 1972) shows a storage rack intended specifically for test tubes. It incorporates a base unit and a cooperating cover unit, both made of vacuum-formed thermoplastic such as polypropylene, in which the base unit is a one-piece deep-drawn bucket shape having at its bottom a plurality of evenly spaced tetrahedron-shaped wells, each adapted to receive and support an individual test tube. A drain opening is provided at the bottom of each well to permit condensate to escape.  
         [0006]     Korum U.S. Pat. No. 4,284,603 (Aug. 18, 1981) discloses a three-piece test tube rack, open at the sides, in which the component parts may be stored separately and then snapped together for use. The top component has clear-through openings allowing the test tubes to be inserted; the middle component has corresponding clear-through openings for center support; and the base component has semi-closed wells instead of clear-through openings to prevent the test tubes from falling out while still allowing drainage. The base and cover are therefore of necessity not identical, although the specification suggests that the base and cover can be produced using the same mold (col. 3, lines 1-3). Clearly a separate supply of both tops and bases would have to be kept on hand in order to use the device at all, which is a problem solved by the present invention.  
         [0007]     Mehra U.S. Pat. No. 4,588,095 (May 13, 1986) shows a complex one-piece injection molded test tube rack having perforated wells at the bottom, and grids for the middle and top supports. The claimed invention resides in the device as a single integral piece, distinguishing it from multi-component units which allow compact nested storage prior to assembly for use, as with the present invention.  
       SUMMARY OF THE INVENTION  
       [0008]     It is therefore a principal object of the invention to provide an improved test tube rack and covered container, made of inexpensive injection-molded or thermoformed plastic, such as PVC (polyvinyl chloride) (utility and virgin), rPVC (recycled polyvinyl choride), and rPET (recycled polyethylene terapthalate), or other materials, for instance polystyrene (PS) or polycarbonate (PC). The ideal material of these is rPVC, although it is more expensive. These plastics can be made in transparent form to readily allow inspection and observation of the container&#39;s contents.  
         [0009]     Another object of the invention is to provide such a container comprising only three or four parts, comprising a tray, a cover, a central support panel and/or a lower support panel, of which two (the tray and cover) are identical shells. The assembled test tube rack has sufficient depth to accommodate test tubes, or other axially elongated articles, of varying height, while the central support panel and the lower support panel provide positive positioning and support to each test tube or article, to prevent tipping and spilling during shipping and handling. A related object is to provide such a container in which the identical shells (the tray and the cover) are nestable, for compact and convenient storage, and to reduce the total number of different components which a laboratory must keep on hand. Alternatively, a tray may be utilized without a cover, in applications where the cover is not needed.  
         [0010]     As a further object of the invention, the identical tray and cover shells are provided at their adjoining flanges with cooperating tabs and depressions which allow the trays and covers to be snapped together (either with or without the central support panel sandwiched between them) to positively hold the test tube rack together, thereby preventing inadvertent tipping and sliding of its contents.  
         [0011]     Another desirable feature of the invention is that when a technician is finished with a batch of test tubes in a certain tray, the batch of test tubes may be disposed of as a unit merely by snapping a cover over them to prevent tipping and spilling as they are taken to a disposal point such as a biohazard trash can or sharps container. 
     
    
     A BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     In the drawings:  
         [0013]      FIG. 1  is an exploded perspective view of the first preferred embodiment of improved test tube rack showing the lower shell, upper shell or cover, central support panel, and lower support panel (partially cut away) resting on a ledge within the lower shell.  
         [0014]      FIG. 2  is an exploded perspective view of the first preferred embodiment of the improved test tube rack showing only the lower support panel in place . The central support panel is not shown.  
         [0015]      FIG. 3  is a perspective view of the first preferred embodiment of the improved test tube rack showing the tray and the cover snapped together.  
         [0016]      FIG. 4  is a partially broken away fragmentary side view of the first preferred embodiment showing test tubes of varying heights secured only by the lower support panel. The central support panel is not shown.  
         [0017]      FIG. 5  is a partially broken away fragmentary perspective view of the first preferred embodiment of the improved test tube rack showing a tab and a depression functionally engaged, and the lower support panel secured on the peripheral ledge.  
         [0018]      FIG. 6  is an exploded perspective view of the second preferred embodiment of the improved test tube rack utilizing a central support panel only.  
         [0019]      FIG. 7  is a partially broken away fragmentary side view of the second preferred embodiment showing test tubes of varying heights secured by the central support panel and also the interconnecting relationship of the tab, depression, and the central support panel.  
         [0020]      FIG. 8  is a partially broken away fragmentary perspective view of the second preferred embodiment of the improved test tube rack showing the interconnecting relationship of the tab, depression, and the central support panel.  
         [0021]      FIG. 9  is a partially broken away fragmentary perspective view of a second type of central panel for use with the first preferred embodiment, having perforated edges which may be separated by hand to reduce its size, enabling it to be used as a lower support panel. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
     A First Preferred Embodiment  
       [0022]     Turning to the drawings,  FIGS. 1-5  show the first preferred embodiment of the improved test tube rack.  FIG. 1  shows an exploded view of the four components of the first preferred embodiment of the improved test tube rack  10  comprising a first shell serving as a tray  12 , a second shell serving as a cover  14 , the central support panel  16 , and the lower support panel  18 .  
         [0023]     The first and second shells are identical pieces and form the tray  12  and the cover  14 . The tray  12  and the cover  14  each have an array of hemispherical protrusions corresponding to the positions of the test tubes to be contained within. As a tray  12 , the protrusions become wells  20  to cradle and position the test tubes. As a cover  14 , the protrusions become domes  22 , which fit over, and thereby position, a test tube long enough to touch at both the top of the cover  14  and the bottom of the tray  12 . The wells  20  and domes  22  also have an additional protrusion forming a pocket  23  which, when the shell is a tray  12 , serves on the inside of the test tube rack to catch spilled material from the test tubes, and also, on the outside of the test tube rack, to provide a cushion between the test tubes and a hard surface onto which a technician might place a filled test tube rack. The pockets  23  serve as a measure of protection against breakage of the test tubes within the test tube rack.  
         [0024]     According to the invention, the tray  12  and cover  14  are identical in shape, and can be formed in the same mold. The tray  12  has side walls and end walls to define a rectangular opening and also has a tray bottom  24 . Each cover  14  has side walls and end walls to define a second rectangular opening and each cover  14  has a cover top  26 . Because the rectangular opening of each tray  12  and cover  14  is larger than the corresponding bottom  24  or top  26 , the shells have a taper, which makes them nestable, one inside the other, for compact and convenient storage.  
         [0025]     A peripheral tray flange  28  is located around the rectangular opening of the tray  12  and a peripheral cover flange  30  is located around the second rectangular opening of the cover  14 . The peripheral tray flange  28  and the peripheral cover flange  30  each include cooperating tab-and-depression positioning units A molded-in protruding tab  32  on one side of the tray  12  is received and retained by a molded-in recessed depression  34  on the facing side of the cover  14 , so that the tray  12  and cover  14  may be frictionally attached and retained simply by pressing them together. By forming the tabs  32  at opposite sides of the tray  12  and cover  14 , and the depressions  34  at the other sides, the same shell may be used for both tray  12  and cover  14 , because they will mate together when a tray  12  is snapped to a cover  14 .  
         [0026]     The central support panel  16  contains openings  36  which are in alignment with the wells  20  in the tray  12  and the domes  22  in the cover  14  and serve to support the test tubes in the test tube rack. The central support panel  16  also has aligning openings  38  which are in alignment with the tabs  32  and the depressions  34 . The tabs  32  protrude through the aligning openings  38  and align over the depressions  34  and serve to secure the central support panel  16  in place on top of the peripheral tray flange  28 . When the cover  14  is added, the tabs  32  of the cover  14  protrude through the aligning openings  38  further fixing the central support panel  16  in place as the tray  14  and cover  12  frictionally lock together as described above.  
         [0027]     When a tray  12  and cover  14  have been snapped together, the assembled test tube rack may be stacked on top of another assembled test tube rack by placing one on top of the other and positioning the wells  20  of the upper test tube rack on the cover top  26  between the domes of the lower test tube rack. This stackability of the test tube racks is convenient for storing assembled test tube racks on the lab bench on in the refrigerator.  
         [0028]     As a further feature of the first preferred embodiment of the invention, a peripheral ledge  40 , located on the inside of the side walls and end walls and around the perimeter of the shell located at approximately the midpoint of the height of the shell, holds the lower support panel  18 . The lower support panel  18  has holes  42 , which are akin to the openings  36  in the central support panel  16 , and serve to support the test tubes in the test tube rack. The lower support panel  18  may be used with or without the central support panel  16 . Similarly, the central support panel  16  may be used with or without the lower support panel  18 . Using both the central support panel  16  and the lower support panel  18  together provides additional support which may be required for taller test tubes. Use of the lower support panel  18  alone without the central support panel  16  in place works well for smaller test tubes.  
         [0029]     Also, preferably, the peripheral ledge  40  has grooves  44  spaced around its perimeter, ideally one or two per side of a shell. Trapezoidal shaped nibs  46  located on the inside of the side walls and end walls above the peripheral ledge  40  and aligned over the grooves  44  serve to connectively engage and secure the lower support panel  18  in snap-in relationship. The grooves  44  provide a space below the peripheral ledge  40  so that the lower support panel  18  can be pushed down vertically as it is snapped into place and secured under the nib  46  and on top of the peripheral ledge  40 .  
         [0030]     In the first preferred embodiment, the peripheral tray flange  28  and the peripheral cover flange  30  each have corners with a notch  48 . As shown in  FIG. 3 , when the peripheral tray flange  28  and the peripheral cover flange  30  are facing each other and the tray  12  is snapped to the cover  14 , the notch  48  on the tray  12  and the notch  48  on the cover  14  sit in opposite orientations, which provide handles to grab in order to facilitate removing the cover  14  from the tray  12 .  
         [0031]     As a further feature of the invention, some or all of the components of the improved tray are made of a transparent thermoplastic material to readily permit inspection of the tray&#39;s contents. The following plastics have been found to be suitable for this purpose: PVC (polyvinyl chloride) (utility and virgin), rPVC (recycled polyvinyl chloride), rPET (recycled polyethylene terapthalate), PS (polystyrene) and PC (polycarbonate).  
       A Second Preferred Embodiment  
       [0032]      FIGS. 6-8  show a second preferred embodiment of the improved test tube rack.  FIG. 6  shows an exploded view of the three components of the this second embodiment of the improved test tube rack  100  comprising a first shell serving as a tray  112 , a second shell serving as a cover  114 , and the central support panel  116 .  
         [0033]     The first and second shells are identical pieces and form the tray  112  and the cover  114 . The tray  112  and the cover  114  each have an array of hemispherical protrusions corresponding to the positions of the test tubes to be contained within. As a tray  112 , the protrusions become wells  120  to cradle and position the test tubes. As a cover  114 , the protrusions become domes  122 , which fit over, and thereby position, a test tube long enough to touch at both the top of the cover  114  and the bottom of the tray  112 . The wells  120  and domes  122  also have an additional protrusion forming a pocket  123  which, when the shell is a tray  112 , serves to catch spilled material from the test tubes and also, on the outside of the test tube rack, to provide a cushion between the test tubes and a hard surface onto which a technician might place a filled test tube rack. The pockets  123  serve as a measure of protection against breakage of the test tubes within the test tube rack. When a tray  112  and cover  114  have been snapped together, the assembled test tube rack may be stacked on top of another assembled test tube rack by placing one on top of the other and positioning the wells  120  of the upper test tube rack on the cover top  126  between the domes of the lower test tube rack. This stackability of the test tube racks is convenient for storing assembled test tube racks on the lab bench on in the refrigerator.  
         [0034]     According to the invention, the tray  112  and cover  114  are identical in shape, and can be formed in the same mold. The tray  112  has side walls and end walls to define a rectangular opening and also has a tray bottom  124 . Each cover  114  has side walls and end walls to define a second rectangular opening and each cover  114  has a cover top  126 . Because the rectangular opening of each tray  112  and cover  114  is larger than the corresponding bottom  124  or top  126 , the shells have a taper, which makes them nestable, one inside the other, for compact and convenient storage.  
         [0035]     A peripheral tray flange  128  is located around the rectangular opening of the tray  112  and a peripheral cover flange  130  is located around the second rectangular opening of the cover  114 . The peripheral tray flange  128  and the peripheral cover flange  130  each include cooperating tab-and-depression positioning units. A molded-in protruding tab  132  on one side of the tray  112  is received and retained by a molded-in recessed depression  134  on the corresponding side of the cover  114 , so that the tray  112  and cover  114  may be frictionally attached and retained simply by pressing them together. By forming the tabs  132  at opposite sides of the tray  112  and cover  114 , and the depressions  134  at the other sides, the same shell may be used for both tray  112  and cover  114 , because they will mate together exactly, not only when a tray  112  is shaped to a cover  114 , but also when a tray  112  is nested within a cover  114 .  
         [0036]     The central support panel  116  contains openings  136  which are in alignment with the wells  120  in the tray  112  and the domes  122  in the cover  114  and serve to support the test tubes in the test tube rack. The central support panel  116  also has aligning openings  138  which are in alignment with the tabs  132  and the depressions  134 . As shown in  FIGS. 7 and 8 , the tabs  132  protrude through the aligning openings  138  and align over the depressions  134  and serve to secure the central support panel  116  in place on top of the peripheral tray flange  138 . When the cover  114  is added, the tabs  132  of the cover  114  protrude through the aligning openings  138  further fixing the central support panel  116  in place as the tray  114  and cover  112  frictionally lock together as described above.  
         [0037]     An additional feature applicable to the first embodiment of the invention is shown in  FIG. 9 , which illustrates a dual-purpose support panel  216  having perforated edge strips  247  which can be easily separated by hand and removed. As supplied with the tray assembly, the support panel  216  serves the purpose of the central support panel  16  of  FIG. 1 , and has openings  238  adapted to engage the tabs  32  of the tray  12 . By simply separating the edge strips at their perforations, the external dimensions of the separator  14  are reduced sufficiently to fit into the lower shell  12  and whereby it can rest on the ledge  40  ( FIGS. 4 ) and serve as the lower support panel  18 .  
         [0038]     In practice, the test tube rack of the first preferred embodiment is supplied with two dual-purpose support panels  216 , which at the option of the user can employed in several ways. For example, if only one support panel is required, the other can be discarded. If extra support is needed, the two support panels  216  can be superimposed and used together. Or, if both a central and lower support panel are required, one of the dual-purpose support panels  216  is reduced in size by pulling off its edge strips at their perforations ( FIG. 9 ), enabling it to be inserted down into the tray  12  to rest on its internal peripheral ledge  40  in the manner shown in  FIG. 4 .  
         [0039]     As a further feature of the invention, some or all of the components of the improved tray are made of a transparent thermoplastic material to readily permit inspection of the tray&#39;s contents. The following plastics have been found to be suitable for this purpose: PVC (polyvinyl chloride) (utility and virgin), rPVC (recycled polyvinyl chloride), rPET (recycled polyethylene terapthalate), PS (polystyrene), and PC (polycarbonate).