Patent Publication Number: US-2007110616-A1

Title: Lead detection swab kit

Description:
BACKGROUND OF THE INVENTION  
      The present invention pertains to a kit for determining the presence of lead. More particularly, the present invention pertains to a kit for determining the presence or absence of lead and recording that presence or absence determination.  
      For many years, electronic component assembly relied upon materials, and specifically solder, that contained lead. Many countries are contemplating laws and other regulations that restrict the use of lead in solder. Moreover, even though industry trends are tending toward the use of lead-free materials, many components presently made and in use contain leaded solder.  
      In order to assure that personnel are protected from lead, it is desirable to test the solder on a printed circuit board prior to commencing work on the board. Known types of test devices use acid to transfer material (lead and other solder constituent materials) from the solder to media onto which a chemical indicator is applied to indicate the presence or absence of lead. In one known device, an acid-containing reagent is in a breakable vial or is pre-applied to a swab which is then rubbed on the surface of the solder. The reagent changes color in the presence of lead.  
      One of the drawbacks to this device or system is that a liquid, and likely an acid, is contacted with or applied to the solder on the board. This, or course has its inherent drawbacks. Another is that this system is merely a system to determine the presence or absence of lead and does not provide any means to record that determination.  
      Accordingly, there is a need for a lead detection kit that does not require the application of a liquid (acid solution) to the material being tested. Desirably, such a kit permits the recordation of such a determination.  
     BRIEF SUMMARY OF THE INVENTION  
      A lead detection is used to detect the presence or absence of lead in a sample, such as that from a circuit board. The kit is intended or use where maintenance or rework is required on the sample, and it is desirable to determine, prior to work, whether there is lead in any of the materials in the sample. Such a kit eliminates the need for application of a liquid, such as an acid solution, to the material being tested.  
      The kit includes a label having spaces thereon indicated for the completion of information. The label has a lead indicating test strip mounted thereto that indicates the presence or absence of lead. The kit includes a swab having an abrasive tip.  
      The swab is rubbed on the surface of the sample to transfer a portion of the sample onto the swab. The test strip is wetted with a wetting solution, and the portion of sample is transferred onto the wetted test strip. The test strip changes color to indicate the presence of lead. Conversely, failure to change color indicates the absence of lead.  
      The label is preferably an adhesive backed label. Preferably, the label has a first removable portion indicating that the sample contains lead and a second removable portion indicating that the sample does not contain lead. The appropriate portion can be placed on the sample, e.g., the circuit board or component in which the circuit board resides.  
      The wetting solution is a lead detection activation solution, such as deionized water. The kit can further include a set of instructions for use of the kit.  
      These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.  
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
      The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein:  
       FIG. 1  is plan view of a lead detection swab kit embodying the principles of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated.  
      It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein.  
      Referring now to the figures and in particular to  FIG. 1  there is shown a lead detection test kit  10  embodying the principles of the present invention. The kit  10  includes tools to test for the presence or absence of lead on, for example, a printed circuit board. The kit  10  includes an adhesive label  12  that can be applied to, for example, the board, a component in which the board is installed, or any other surface for record keeping purposes. The label  12  includes a dried indicator  14 , such as a test paper strip that is impregnated with an indicator  16  such as rhodizonate. The strip  14  is affixed to the label  12  to provide permanent or semi-permanent indication.  
      The label  12  further includes areas  18  in which specific information is to be completed. The information can include: the date  18   a ; identification of the individual performing the test  18   b ; identification of the part that is being tested  18   c ; a notebook or test number  18   d ; and indication  18   e  of whether lead is indicated by the test. Other and/or different information can also be included on the label  12  as desired.  
      The kit  10  also includes a swab  20 . The swab  20  includes a handle  22  and a sampling head  24 . The sampling head  24  is formed from an abrasive material that retains its integrity in use. That is, the abrasive material does not flake or rub off of the head  24  as it is rubbed on the material to be tested or on surface of the test strip  14 . However the grit or roughness of the material cannot be so great as to fray the strip  14  when it is rubbed on the strip  14 . The kit  10  further includes a wetting solution  26 , which serves as a lead detection activation solution. The solution  26  brings the sample to be tested into intimate contact with the test strip  14  in a liquid environment. In a present kit  10 , the solution  26  is water, preferably, deionized water.  
      The kit  10  includes an instruction sheet  28 . The instructions  28  delineate the method carried out to test the sample. The instructions provide for grasping the swab  20  and holding it between the thumb and forefinger, by the handle  22  just above the head  24 ; rubbing or twisting the head  24  tip of the swab  20  on the solder joint being tested (to collect the sample) for 30 to 45 seconds; pressing the swab  20  firmly but without smashing the head  24  more than 1/16 inch; inspecting the head  24  of the swab  20  for gray residue from the joint, and if the head  24  is not gray, making sure that the joint is not covered in coating or contaminant, in which case the coating or contaminant must be removed from the joint to collect a good sample, and alternately selecting another joint for testing; placing a drop of lead detector activator solution  26  on the test strip  14 ; gently twisting the head  24  of the exposed swab  20  on the dampened test strip  14  for 30 to 45 seconds assuring that the head  24  is making contact with the strip  14  but is not penetrating (tearing through) the strip  14  material; visually examining the test strip  14  to determine whether the test strip  14  changes color (to red or purple) within about 2 to about 15 minutes indicating that lead is present; recording the results and notations (information) on the label  12  in the appropriate spaces  18   a - e  and storing the label  12  for future records or affixing the label  12  to other paper; and optionally securing the appropriate label portion “Contains Lead”  30   a  or “No Lead” (or “Lead Free”)  30   b  to the tested circuit board.  
      A method for testing and marking or labeling a sample includes applying the label  12  to a sample or a component that contains the sample, rubbing the swab head  24  on the sample to transfer a portion of the sample onto the swab  20 , wetting the test strip  14  with an activator solution  26  and rubbing the swab head  24  on the test strip  14  to transfer at least some of the sample from the head  24  onto the strip  14 . If the test strip  14  changes color, then lead is present, and if the test strip  14  does not change color then lead is not present. The results (information) can be marked in the appropriate spaces  18   a - e  on the label  12 . If the label  12  contains removable portions or tabs  30   a,b  that indicate the presence or absence of lead, the appropriate tab (“Contains Lead”  30   a  or “No Lead” (or “Lead Free”)  30   b  label portion) can be remove from the label  12  and applied to the sample, e.g., the circuit board or the component that contains the circuit board.  
      All patents referred to herein, are hereby incorporated herein by reference, whether or not specifically do so within the text of this disclosure.  
      In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular.  
      From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.