Patent Publication Number: US-6663836-B1

Title: Apparatus and method for alphanumerically identifying and arranging test tubes

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part (CIP) of application designated Ser. No. 08/720,723, filed Oct. 2, 1996, now issued as U.S. Pat. No. 6,171,554 B1 and entitled “Apparatus And Method For Alphanumerically Identifying And Arranging Test Tubes”. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to laboratory technology and specifically to a new and improved rack of test tubes suitable for use in diagnostic methods. 
     2. Background of the Invention 
     It is known to provide multi-well racks for test tubes. Conventionally, the wells may be located at the intersections of mutually perpendicular columns and rows aligned with  1 AS alphanumeric markings along perpendicular edges of the rack. Alternatively, instead of employing alphanumeric markings along the rack edges, in order to assist laboratory personnel in properly orienting the racks, markings may be applied at a corner as shown, for example, at  42  in FIG. 5, or a corner of the rack may be chamfered as shown at  44  in FIG.  6 . Test tubes are supported in the wells. If the tubes are not labeled, and if more than one tube is removed from the rack at any given time, errors may be made when returning the tubes to the rack. The tubes may also be manually marked with an alphanumerical designation to identify their appropriate positions in the array of wells. In addition to being time consuming and laborious, this practice can also lead to errors caused by laboratory technicians either mislabeling the tubes or again, returning properly labeled tubes to the wrong wells. 
     SUMMARY OF THE INVENTION 
     In one embodiment of the present invention, these problems are avoided, or at least significantly minimized, by simultaneously marking all of the test tubes in a given rack with alphanumeric indicia corresponding to the alphanumeric indicia identifying the wells within which the test tubes are to be located. Preferably, the wells are open bottomed to expose the lower tube ends, and the alphanumeric markings are applied to the thus exposed tube bottoms. 
     Alternatively, the racks may be oriented by reference to visible features, e.g., corner markings or chamfers. 
     The wells may have closed bottoms, in which case the tubes are marked prior to being placed in the racks. 
     A matrix of tubes may be assembled on mandrels, indicia printed on the matrix of tubes, and the entire matrix then transferred into a rack such that each tube is located in its predetermined location. 
     In still another embodiment, the tubes may be marked with a laser before being placed in either a labeled or unlabeled rack. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view of a rack of tubes in accordance with the present invention with the lid and several individual tubes depicted in an exploded relationship; 
     FIG. 2 is an enlarged cross-section of the rack and assembled lid; 
     FIG. 3 is a top plan view of the rack of tubes with the lid removed; 
     FIG. 4 is a bottom plan view of the rack of tubes; and 
     FIG. 5 is a view of an alternative rack of tubes with the lid and several individual tubes depicted in an exploded relationship; 
     FIG. 6 is a perspective view of another alternative embodiment of the rack; 
     FIG. 7 is an enlarged cross-section view of a closed bottom rack of tubes with the lid removed; and 
     FIG. 8 is a perspective view of a set mandrels having several test tubes placed on some of the mandrels. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring initially to FIGS. 1-4, a rack of tubes in accordance with the present invention is shown generally at  10  with its associated lid  12 . The rack  10  includes wells indicated typically at  14 . As shown in FIG. 3, the wells  14  are located at the intersections of mutually perpendicular columns  16  and rows  18  aligned with alphanumeric markings  20  along perpendicular edges  22 ,  24  of the top surface of the rack. In the illustrated embodiment, each column  16  is labeled with a number and each row is labeled with a letter to define the position of each well  14 . 
     The wells  14  are configured and dimensioned to support test tubes indicated typically at  26 . The bottom ends of the test tubes protrude through the open bottoms of the wells and are thus exposed, as shown in FIGS. 2 and 4. The exposed tube ends are marked, as by printing, with alphanumeric indicia indicated typically at  32  corresponding to the alphanumeric locations of the wells in which the tubes  26  are supported. The lid  12  is detachably mounted on the rack  10  to keep the tubes  26  in place, both during as well as after applying the indicia  32  to the tube ends. 
     The lid  12  includes internal corner ribs  35  which abut the upper surface of the rack  10  as at  36  to provide a positive locating function. Resilient locking tabs  38  mechanically engage the rack as at  40  to detachably secure the lid in place. 
     Some racks  40 , disposable carriers and plates do not have alphanumeric markings along the edges thereof to label the columns and/or rows as illustrated in FIGS. 5 and 6. However, it is generally known to laboratory personnel using the racks that the rows are conventionally identified by letters i.e. A, B, C, whereas the columns are identified by numbers, i.e.  1 ,  2 ,  3 , to define the position of each well  14 , the same as for the racks which include the alphanumeric markings. When using a rack or carrier without alphanumeric markings, as previously noted, the rack may be marked as at  44  such as shown in FIG. 5, or chamfered as at  44  as indicated in FIG. 6 to provide an orientation reference. 
     With reference to the embodiment shown in FIGS. 1-5, the method of applying indicia  32  to the test tubes may comprise the following steps: unmarked test tubes  26  are placed in the wells  14 ; the lid  12  is secured to the rack; the assembled lid and rack are inverted to expose the lower tube ends; and the lower tube ends are printed with alphanumeric designations corresponding to alphanumeric designations (whether or not printed along the edges  22 ,  24  of the rack). 
     Alternatively, the tubes may first be positioned in a fixture having wells with open bottoms. The tubes are printed as described above, and after printing they are removed as a group from the fixture and placed into a second fixture. The second fixture may be a rack  48  having closed bottomed wells as shown in FIG.  7 . The second fixture may also be a cartridge designed to hold the tubes during the printing process. The cartridge may then be provided to laboratory personnel who will employ the cartridge as an insert into racks already in their possession. 
     In accordance with another embodiment, a matrix of tubes may be assembled on mandrels  50  as shown in FIG.  8 . The matrix of tubes may be printed simultaneously then transferred to an open or closed bottom rack with or without alphanumerics along the edges thereof. 
     When the tubes are printed while they are positioned in the rack or fixture or on the set of mandrels, one eliminates the possibility that a printed tube will be loaded into an incorrect position. Also, as all of the tubes are printed at one time, only one art set-up is required. 
     Alternatively, the tubes may be individually laser marked and then placed within a rack or carrier in positions which corresponds to their markings. 
     The tubes may be made of a polymeric material, specifically a polyolefin, and more specifically polypropylene or the tubes may be made of glass. The indicia printed on the tubes should be resistant to solvents, scratching, etc. To this end, the polypropylene tubes preferably are pretreated by corona discharge and placed under a flame before being pad printed. This pretreatment oxidizes the tube surface and this optimizes its receptivity to the printed indicia. 
     The forgoing description has been limited to a specific embodiment of the invention. It will be apparent, however, that variations and modifications can be made to the invention, with the attainment of some or all of the advantages. For example, the number of wells in the rack may be altered or the array may only include letters rather than numbers or another printing or marking method may be utilized. Therefore, it is the object of the claims to cover all such variations and modifications as come within the true spirit and scope of the invention.