Abstract:
The invention relates to a puncturing system with a support tape ( 1 ) that supports a plurality of lancets ( 2 ), a first reel ( 3 ) onto which the support tape ( 1 ) with unused lancets ( 2 ) is wound, a second reel ( 4 ) on which portions of the support tape with used lancets ( 2 ) are to be wound, a winding mechanism which, by turning the second reel ( 4 ), brings the lancets ( 2 ) supported by the support tape ( 1 ) to a position of use one after another and thus unwinds the support tape ( 1 ) from the first reel ( 3 ) and winds it onto the second reel ( 4 ), a puncturing drive mechanism ( 7 ) with which lancets ( 2 ) located in the position of use are accelerated in order to puncture the skin. According to the invention, the support tape ( 1 ) between the first and second reels ( 3, 4 ) is twisted only in one direction of rotation by at least a quarter turn, preferably by at least a half turn.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of International Application No. PCT/EP2008/006882, filed Aug. 21, 2008, which claims the benefit of European Patent Application No. EP 07 018 554.1, filed Sep. 21, 2007, the entire disclosures of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a puncturing system having the features defined in the preamble of claim  1 , and to a tape cassette for a puncturing system. A puncturing system of that kind has been known from WO 2005/107596 A2. 
         [0003]    Puncturing systems are used for example by diabetics who have to check their blood-sugar level several times a day and who for that purpose need a sample of a body liquid, as a rule of blood or interstitial liquid, which is gained from a puncture wound produced by a puncturing system. Puncturing systems may comprise a puncturing device and exchangeable tape cassettes with lancet carrier tapes, or may be designed as disposable devices for which an exchange of the integrated lancet carrier tape is not envisaged. 
         [0004]    A lancet carrier tape allows a considerable supply of lancets to be accommodated in a space-saving way. Accordingly, puncturing devices using a lancet carrier tape can be given a very compact design, in spite of a great number of lancets contained in it. This means considerable extra comfort for users who are required to carry along a puncturing device all the time. 
       SUMMARY 
       [0005]    Now, it is an object of the present invention to show how to further improve puncturing systems that use a lancet carrier tape. 
         [0006]    The invention solves that object in that the carrier tape is twisted between the first and the second reel only in one direction by at least one quarter turn, preferably by at least one half turn. 
         [0007]    Twisting the carrier tape by one quarter turn can bring a portion of the carrier tape into a position transversely to the geometric axis of rotation of the first reel. For carrying out a puncturing action, lancets present on that transversely positioned tape portion can be easily moved transversely to the geometric axis of rotation of the first reel. This allows the puncturing devices to be given a flat design, with the reel disposed horizontally in the housing, and to puncture a part of a body, as a rule a finger, applied to a narrow side of the device, under ergonomically favorable conditions. 
         [0008]    It is especially the orientation of the geometric axis of rotation of the second reel relative to the axis of rotation of the first reel that determines whether the tape can maintain its orientation after that quarter turn or needs further twisting. Preferably, the axes of rotation of the two reels extend in parallel so that the carrier tape should be twisted by a second quarter turn prior to be wound up on the second reel. 
         [0009]    In principle, there is the possibility to make use of the advantage of a quarter turn performed by the carrier tape in a device with parallel geometric axes of rotation of the reels by providing that the first quarter turn is reversed by a second quarter turn in opposite sense of rotation. In that case the carrier tape would be twisted in two different senses of rotation between the two reels. 
         [0010]    However, twisting the carrier tape in a single direction of rotation is much more advantageous. In a puncturing system with parallel axes of rotation of the reels this means that instead of reversing the first quarter turn by a second quarter turn the carrier tape is twisted further in the direction of rotation of the first quarter turn, preferably by exactly another quarter turn, with the result that the carrier tape is twisted by a total of one half turn. 
         [0011]    If the carrier tape is twisted in a single direction of rotation, a smaller number of tape guiding elements are needed than in the case of oppositely directed quarter turns that compensate each other. A smaller number of tape guiding elements not only leads to a simpler and, accordingly, cheaper structure of the puncturing system, but also results in less friction. 
         [0012]    This is so because a smaller number of tape guiding elements as a rule also leads to smaller friction surfaces, that act on the carrier tape, and/or a smaller angle of wrap about which the carrier tape has to be guided by the tape guiding elements. Reduced friction means that less force will be needed for transporting the tape. Puncturing systems that use an electric motor for transporting the tape therefore can be given a motor of lower power and require less electric energy. Recharging or exchanging the batteries, which is a nuisance to many users, is then necessary more seldom, or else the weight of the device can be further reduced and its design can be made more compact by the use of smaller batteries. For simpler puncturing systems, where the tape is transported by a force to be applied by the user, reduced friction means an agreeable additional comfort to users whose manual mobility is limited by age or disease. 
         [0013]    A puncturing system according to the invention may comprise a tape cassette having the features defined in claim  7  and a puncturing device into which the tape cassette is loaded for being exchanged when all lancets on the carrier tape have been used up. However, a puncturing system according to the invention may also be realized as a disposable device which is not designed for an exchange of the carrier tape and which is discarded when all lancets of the carrier tape in the puncturing device have been used up. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Further details and advantages of the invention will be described with reference to certain embodiments and to the attached drawings. Identical and corresponding components are indicated by the same reference numerals. The features described with reference to the different embodiments may be made the subject of claims either individually or in any combination. In the drawings: 
           [0015]      FIG. 1  shows an embodiment of a puncturing system according to the invention, with the housing in open condition; 
           [0016]      FIG. 2  shows a diagrammatic representation of the tape guiding; 
           [0017]      FIG. 3  shows a diagrammatic representation of an embodiment of a carrier tape according to the invention; 
           [0018]      FIG. 4  shows an embodiment of a puncturing device for use in the tape cassette shown in  FIG. 3 ; 
           [0019]      FIG. 5  shows a diagrammatic representation of the tape exit opening of the tape cassette shown in  FIG. 3 ; and 
           [0020]      FIG. 6  shows a diagrammatic representation of the tape entry opening of the tape cassette shown in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]      FIG. 1  shows an embodiment of a puncturing system with an opened device housing, comprising a carrier tape  1  that carries a plurality of lancets  2  oriented transversely to its lengthwise direction. The carrier tape  1 , carrying unused lancets  2 , is wound up on a first reel  3 . Carrier tape portions with used lancets  2  are wound up on a second reel  4 . The second reel  4  is driven by a reel drive which in the illustrated embodiment is designed as a drive wheel  6  that projects from the device housing  5 . By rotating the second reel  4 , the lancets  2  carried on the carrier tape  1  can be transported one by one to a position of use, whereby the carrier tape  1  is unwound from the first reel  3  and is wound up on the second reel  4 . In the condition of use, the lancets  2  can be accelerated by a puncturing drive  7  in order to puncture the skin of a part of a body applied to a device opening  8  to produce a puncture wound from which a sample of a body liquid can be gained. 
         [0022]    The lancet drive  7  comprises a drive head  9  with a slot in which the carrier tape  1  is held. The drive head  9  is driven via a connecting rod  10  coupled to a rotor  11  which latter is driven by a drive spring  12  that may be configured as a spiral spring. The drive spring  12  can be tensioned by operation of the drive wheel  6  which simultaneously serves as a tape transport member. An actuator element  13 , preferably a key, serves to trigger the puncturing movement. 
         [0023]    Between the two reels  3 ,  4  the carrier tape  1  is guided over two tape guiding elements  14 . Between them is the position for use. The tape guiding elements  14  are configured as redirecting elements. The guide elements may take the form of pins or housing edges. Preferably, the redirecting elements are rolls which may be designed, for example, as sleeves rotatably seated on pins. The tape guiding elements  14  may also be designed as simple pins, for example. Rolls provide the advantage that the tape can be transported with less friction. 
         [0024]    A particularity of the illustrated puncturing system consists in the fact that the carrier tape  1  is twisted between the first and the second reel in only one direction of rotation. On the whole, the carrier tape is twisted by a half turn between the two reels  3 ,  4 . The position for use, in which the lancet  2  can be used for puncturing the skin of a part of a body applied to the housing opening  8 , is located in the tape portion that is twisted by a half turn, the carrier tape  1  being twisted by a quarter turn on each side of the position for use. A first quarter turn between the first reel  3  and the position for use brings the carrier tape  1  into an orientation in which the lancets  2  carried on the tape  1  are positioned transversely, for example vertically, to the geometric axis of rotation of the first reel  3 . 
         [0025]    In the illustrated embodiment, the lancets  2  are arranged transversely to the longitudinal direction of the carrier tape  1  and, consequently, behind the first quarter turn, aligned in the puncturing direction. 
         [0026]    The second quarter turn, which has the same sense of rotation as the first quarter turn, returns the lancets  2  to their upright position so that they come to extend in the longitudinal direction, preferably parallel to the geometric axis of rotation of the second reel  4 . Preferably, the geometric axes of rotation of the two reels  3 ,  4  extend in parallel one to the other, although a different orientation is also possible. 
         [0027]    By providing that the carrier tape  1  is twisted in a single direction only, no other tape guide elements are needed in addition to the tape guiding elements  14  mentioned before. Especially, no separate tape guiding elements are required for producing the quarter turns between the position for use and the two reels  3 ,  4 . The illustrated puncturing system therefore provides an especially low-friction way of transporting the tape. 
         [0028]    The twist of the carrier tape  1  between the two tape guiding elements  14  is illustrated diagrammatically in  FIG. 2 , viewed in a direction opposite to the puncturing direction. 
         [0029]      FIG. 3  shows a diagrammatic representation of one embodiment of a tape cassette  20  for use in a puncturing device  30  of the type shown in  FIG. 4 , for example. 
         [0030]    The tape cassette  20  comprises a housing  21 , containing a carrier tape  1  which carries a plurality of lancets  2  arranged preferably transversely to the lengthwise direction of the tape  1 . Similar to the arrangement of the first embodiment shown in  FIG. 1 , the carrier tape  1  is wound up in the cassette  20  on a first reel from which it can be unwound and wound onto the second reel (not shown in  FIG. 4 ) by rotation of the second reel. As in the case of the puncturing system illustrated in  FIG. 1 , the carrier tape  1  of the tape cassette  20  illustrated in  FIG. 1  is twisted only in a single direction, preferably by a half turn. 
         [0031]    The carrier tape  1  leaves the housing  21  of the tape cassette  20  through an exit opening  22 , and enters the housing  21  again through an entry opening  23 . Between the exit opening  22  and the entry opening  23 , the carrier tape  21  is twisted by one half turn. 
         [0032]    In addition to the lancets  2 , the carrier tape  1  of the embodiment illustrated in  FIG. 3  carries test fields  24  for examination of a sample of a body liquid that has been gained by a puncturing operation of a lancet. The test fields  24  contain indicator reagents that permit an analyte concentration, for example a glucose concentration, to be determined by photometric or electrochemical means. Corresponding test fields are contained in commercially available test strips intended, for example, for blood sugar determination, and need not be discussed here in more detail. Preferably, the test fields  24  are located between the lancets  2 . 
         [0033]      FIG. 4  shows an embodiment of a puncturing device  30  into which the tape cassette  20  can be loaded for use. The puncturing device  30  comprises a compartment (not shown) intended to hold the tape cassette  20 . The compartment is provided with an opening, that can be closed, on the back of the embodiment illustrated in  FIG. 4 . 
         [0034]    The puncturing device  30  is provided with a device opening  31  against which a part of a body is pressed for being punctured. The puncturing device  30  further comprises operating elements  32 , for example keys, and a display means, for example a liquid crystal display. 
         [0035]    The illustrated puncturing device  30  comprises a reel drive intended to rotate a second reel of a loaded tape cassette  20  and to thereby bring the lancets  2  and the test fields  24  of the carrier tape  1  successively into a position for use. Preferably, the reel drive is battery-driven, as is a puncturing drive contained in the puncturing device  30 . Besides, the puncturing drive may be configured identically to the puncturing drive of the embodiment illustrated in  FIG. 1 , where an electric motor is used for tensioning the moving spring. 
         [0036]    The puncturing drive accelerates not only lancets  2  in the position for use for performing a puncturing action, but also the test fields  24  in the position for use for performing a sampling movement in the puncturing direction. 
         [0037]    Preferably, the illustrated puncturing device  30  further comprises a measuring device intended to measure the result of a test reaction performed by the test field  24  and an absorbed sample of a body liquid, for determining an analyte concentration. 
         [0038]    Test fields with indicator reagents of the kind existing on the carrier tape of the embodiment illustrated in  FIG. 3  are normally sensitive to humidity. In order to protect the test fields  24  of the carrier tape  1  from humidity and other detrimental environmental influences, the tape exit opening  22  and the tape entry opening  23  of the tape cassette  20  can each be provided with a passage seal. Examples of suitable passage seals are shown in  FIGS. 5 and 6 . 
         [0039]    Due to the half turn by which the carrier tape is twisted between the tape exit opening  22  and the tape entry opening  23 , the test fields  24  carried on the tape face toward the tape cassette  20  as they pass through the housing, for example as they leave the housing, and face away from the tape cassette  20  as they pass the housing in the other direction, for example as they enter the housing. 
         [0040]    In the described embodiment, the test fields  24  have the orientation illustrated in  FIG. 5  when the tape leaves the housing, and the orientation illustrated in  FIG. 6  when the tape enters the housing. Accordingly, after the test fields  24  have left the housing  21  of the tape cassette  20 , they initially face toward the tape cassette, and face away from the housing  21  after the half turn. However, in principle the opposite could also be true. 
         [0041]    The passage seal shown in  FIG. 5  consists of a film  25 , covering the exit opening  22 , and a sealing lip  26  fastened to that film. One surface of the tape is in contact with the housing  21 , the other surface with the sealing lip  26 . In order to facilitate movement of the tape, the housing  21  is provided with a bevel  27  at the edge of the exit opening  22 . The test fields  24  can slide over the bevel  27  of the housing  21  with little friction. 
         [0042]    The sealing lip  26  consists of a soft plastic material, for example an expanded plastic, and exerts pressure only on the plain surface of the tape, the test fields  24  being arranged on the opposite surface of the tape. Accordingly, although the sealing lip  26  is soft and compressible, it produces only little frictional resistance. 
         [0043]    In contrast, in the area of the tape entry opening  23 , the sealing lip  26  is fastened only on the housing  21  so that the tape  1  passes between the film  25  and the sealing lip  26 . In this way, the soft sealing lip  26  is prevented from getting jammed due to unevenness presented by the test fields  24  and the lancets  2 . 
         [0044]    A passage seal on the tape entry opening  23  can be omitted with advantage if the first reel, onto which the unused portions of the carrier tape are wound, is arranged in a chamber that is sealed from the tape entry opening  23 , which is preferred. The tape cassette  20  then preferably contains two separate chambers, each housing one of the two reels. Unused test fields  24  can be protected in the tape cassette  20  additionally by siccatives. 
       LIST OF REFERENCE NUMERALS 
       [0045]      1  Carrier tape 
         [0046]      2  Lancets 
         [0047]      3  First reel 
         [0048]      4  Second reel 
         [0049]      5  Device housing 
         [0050]      6  Drive wheel 
         [0051]      7  Puncturing drive 
         [0052]      8  Housing opening 
         [0053]      9  Drive head 
         [0054]      10  Connecting rod 
         [0055]      11  Rotor 
         [0056]      12  Drive spring 
         [0057]      13  Triggering element 
         [0058]      14  Tape guiding elements 
         [0059]      20  Tape cassette 
         [0060]      21  Housing 
         [0061]      22  Exit opening 
         [0062]      23  Entry opening 
         [0063]      24  Test fields 
         [0064]      25  Film 
         [0065]      26  Sealing lip 
         [0066]      27  Bevel 
         [0067]      30  Puncturing device 
         [0068]      31  Housing opening 
         [0069]      32  Operating element 
         [0070]      33  Display