Abstract:
The present invention provides a test field system, including a test strip with a test field, and a measuring device having a test strip receiver for measuring the test field. The test strip receiver inducing a support surface for the test strip and positioners for holding the test strip inserted in the strip receiver so that a section of the test strip containing the test field is held in a definite position relative to the support surface. The strip receiver having two holding members spaced from one another on edge areas of the support surface for holding fast associated edges of the test strip substantially adjacent the support surface, the support surface in a middle area between the holding means is vertically displaced from the edge areas such that the test field of a test strip inserted in the test strip receiver is spaced apart from the support surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application 09/218,327 filed on Dec. 22, 1998, and abandoned on Jan. 11, 2002. 
    
    
     FIELD OF THE INVENTION 
     The invention concerns a test strip system including at least one test strip with a test field; and for measuring the test field, a measuring device with a strip receiver having a support surface for the test strip, and positioning means, by means of which the inserted test strip is so held in the strip receiver that at least the test field containing section of the test strip takes on a definite position relative to the support surface. 
     BACKGROUND OF THE INVENTION 
     A test strip system of the above-mentioned kind is known, for example, from U.S. Pat. No. 5,424,035. In the solution there described, the support surface rises slightly at the inner end of the strip receiver and has a pin intended to be received in a recess of the strip. Between this holding pin and the spot at which the test field of the test strip is to come to lie in the strip receiver is a rigid pressing element opposite the support surface, the spacing of which pressing element from the support surface is slightly more than the thickness of a test strip. By means of this arrangement the test strip is pressed in slightly bent condition against the support surface so that the test strip, on one hand, hangs firmly on the pin and; on the other hand, the test field, by the bending of the test strip, is pressed against the support surface. The insertion and especially the removal of the test strip are each difficult and complicated and the danger exists that the user, in attempting to pull the test strip from measuring device, either dirties the device or his fingers. 
     The invention has as its object the provision of a test strip system of the a foregoing kind in which the test strip, especially the test field, is held in a definite position with the insertion and removal of the test strip into and out of the strip receiver being simple and easy. 
     SUMMARY OF THE INVENTION 
     This object is solved in accordance with the invention in that the test strip is pressable against an abutment of the strip receiver by a spring force working parallel to the support surface. The abutment defines the position of the test strip on the support surface. Since the test strip itself, however, is very light, a small spring force is sufficient. This spring force can, for example, be created by the test strip, upon its insertion into the strip receiver, being elastically deformed. For example, the test strip can have at least one recess near one of its edges with the contour of the strip material bordering the recess and/or the contour of an adjacent surface of the test strip receiver being so chosen that a bridge formed in the strip material by the recess is deformed upon insertion of the test strip into the strip receiver; the restoring force of the material bridge being sufficient to create the desired spring bias. For example, a nose can be formed at the boundary surface of the strip receiver which presses against the material bridge and slightly deforms it. In the reverse of this, the material bridge can also have an outwardly extending projection which projects beyond the nominal contour of the test strip edge so that the projection, and with it the material bridge, is deflected by the boundary surface of the strip receiver in the direction toward the recess. Thereby, the result again is a restoring force sufficient to press the test strip against an abutment. 
     The last-named embodiment allows in an advantageous way the further formation on the material bridge or on the strip receiver of a recess for partially receiving the projection. Thereby, there is achieved not only a spring force for pressing the strip against the abutment, but also a latching of the test strip to the strip receiver. 
     Another possibility exists in that the strip receiver has arranged in it a spring which pushes the test strip in the receiver against the abutment. The spring is, in this case, advantageously so arranged that its spring force is directed in the sense of a pushing out of the test strip from the receiver. In this case, additional advantages can be achieved if the abutment is formed on a locking element intended to be received in a recess of the test strip. On one hand, the recess can be used to quasi-code the test strip. If the recess (several recesses can also be provided in connection with several locking elements) is not entirely at the designated spot, the locking element cannot move into the recess and the spring moves the test strip again out of the measuring device as soon it is left loose. With this measuring strip, the measuring device can carry out no measurement. If further the locking element is adjustable between an inserted position and a freeing position, the spring can be used after the movement of the locking element to its freeing position to eject the test strip out of the measuring device. 
     According to a further feature of the invention, to solve the problem existing with of a test strip system of the initially-mentioned kind, it is proposed that the test strip receiver have at least two holding means spaced from one another at the edge areas of the support surface for holding fast the associated edges of the test strip and that the support surface, in a middle area between the holding means, be spaced vertically from these edge areas. With this arrangement, the test strip is held at its edge areas and is bent throughout its vertically-displaced middle area, and is thereby stressed so that the test field again has a definite position with respect to the support surface. For example, the support surface can be bent cylindrically, or the support surface can have a projection formed only in its middle portion which projection supports the test field so that by the bending of the test strip over the projection and the strip tension connected therewith, the test field is firmly pressed against the projection. 
     According to a further feature of the invention, for the solution of the mentioned object in a test strip system of the initially-mentioned type, it is proposed that the strip receiver have an outer insertion end and an inner end, that near the inner end a spring arm be arranged which rises vertically out of the support surface and toward the inner end of the strip receiver and is elastically deflectable in the direction toward the support surface, and that the spring arm have associated with it a counter-pressure surface which is spaced from the support surface and which rises away from the support surface and extends toward the inner end of the strip receiver so as to be generally parallel to the direction of the spring arm. 
     If a test strip is inserted into the so-formed strip receiver, it will be pressed by the spring arm against the counter-pressure surface so that it becomes bent or deflected. The restoring force created by the bending of the strip presses the free section of the strip against the support surface so that the test field again lies flatly on the support surface. In order to be able to exactly position the strip, it is advantageous if on the spring arm, a detent extension is formed for reception into a locking recess of the test strip. In contrast to the solution known from U.S. Pat. No. 5,424,035, the test strip can, despite the detention, easily be again pulled out of the device. 
     According to a further feature of the invention, for the solution of the above-named object in a test strip system of the initially-mentioned kind, it is proposed that above the support surface a clamping lever be pivotally supported for movement relative to the support surface about a pivot axis parallel to the support surface, which clamping lever has a clamping arm biased toward the support surface. The test strip can, therefore, be pressed against the support surface by the clamping arm. Here it also is advantageous if the clamping arm has a detent projection for reception in a detent recess of the test strip so that the test strip can be exactly positioned. 
     In a preferred embodiment, the clamping arm of the clamping lever is connected with a second lever arm forming an actuating arm onto which a spring engages for pushing the clamping arm against the support surface. At the same time, the clamping arm can be raised from the support surface by pressing on the actuating arm against the bias of the spring so that a test strip can fall from the strip receiver without the user having to grasp it. 
     To avoid a soiling of the measuring device by the test fluid dropped onto the test strip and, as the case may be, to be better able to clean the strip receiver, the strip receiver can be made as a separate element which is removably insertable in a housing of the measuring device. 
     According to a further feature of the invention, for the solution of the above-mentioned object in a test strip system of the initially-mentioned kind, it is proposed that the measuring device and the test strip be formed for the electrical measurement of the test field through contact elements on the measuring device and on the test strip and that at least one contact element on the measuring device is formed as a clamping spring which presses the test strip in its measuring position against the support surface. In order to release the clamping spring and to free the test strip after its use, an actuating lever is connected with the measuring device, preferably for pivotal movement about an axis parallel to the support surface, and is so associated with the at least one contact spring that the contact spring by pivoting of the actuating lever is lifted from the support surface. After the pivoting of the actuating lever, it is sufficient that the measuring device be held with the insertion opening for the test strip facing downwardly so that the used test strip can fall from the measuring device. 
     Further features and advantages of the invention will be apparent from the following description which in connection with the accompanying drawings explain the invention by way of exemplary embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings are: 
       FIG.  1 —a schematic partial longitudinal section through a test strip measuring device with a test strip according to a first embodiment of the invention. 
       FIG.  2 —a section corresponding to that of  FIG. 1  through a second embodiment of the invention. 
       FIG.  3 —a plan view of the embodiment of  FIG. 2 . 
       FIG.  4 —a schematic plan view of a test strip receiver according to a further embodiment of the invention. 
       FIG.  5 —a view corresponding to  FIG. 4  illustrating a modified embodiment of the invention. 
       FIG.  6 —a view corresponding to  FIG. 4  illustrating yet another modified embodiment of the invention. 
       FIG.  7 —a schematic plan view of a strip receiver with a spring receiver end. 
       FIG.  8 —a view corresponding to  FIG. 7  illustrating a modified embodiment of the invention. 
       FIG.  9 —a schematic plan view of a strip receiver according to a further embodiment of the invention. 
       FIG.  10 —a schematic longitudinal section along the line X-X in  FIG. 9 . 
       FIG.  11 —a schematical section along the line XI-XI in  FIG. 9 . 
       FIG.  12 —a section along the line XII-XII in  FIG. 9 . 
       FIG.  13 —a section along the line XIII-XIII in  FIG. 2 . 
       FIG.  14 —a view corresponding to  FIG. 2  of a further embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The measuring system illustrated in  FIG. 1  includes a measuring device  10  shown only partially in section with a housing lower portion  14  and a housing upper portion  12 , as well as a strip receiver  16  in which a test strip  18  is arranged. 
     The measuring device is, for example, a device for the optical determination of the concentration of a given substance in a liquid, especially body liquids, for example, a device for blood sugar determination or for the quantitative determination of certain substances in urine. The housing  12 , 14  contains a plate  20  with a measuring optic  22  and, in addition to that, a non-illustrated electronic evaluation and control circuit. Further, the measuring device induces an operating part and an indicator device. Measuring devices of this kind are known in themselves and, therefore, do not need to be described in more detail. 
     The strip receiver  16  has a carrier  24  with a support surface  26  for the test strip  18 , as well as a measuring opening  28  through which a test field  30  of the test strip  18  can be measured by the measuring optic  22 . The carrier  24  is pushed into the housing  12 , 14  and held in the housing lower portion  12  by a hook  32 . Provision can be made for allowing the carrier  24  to be removed from the housing  12 , 14  in order, for example, to clean it. 
     A spring arm  34  is so arranged in the carrier  24  that it rises from the support surface  26  and extends inwardly toward the inner end of the strip receiver  16 . The spring arm  34  is biased in the direction of the arrow A and can be pivoted against this biasing force in the direction toward the support surface  26 . 
     The spring arm  34  is associated with a counter-pressure surface  36  connected with the housing upper portion  12  which extends generally parallel to the spring arm  34  and is spaced a given distance from the support surface  26 . 
     Upon insertion of the test strip  18  into the strip receiver  16 , the forward end of the test strip  18 , that is the end facing the inside of the device, moves between the spring arm  34  and the counter-pressure surface  36  so that the test strip  18  becomes bent. In its forward area, the test strip has a detent recess  38  into which a detent nose  40  formed on the free end of the spring arm  34  becomes inserted, if the test strip  18  is inserted fully into the strip receiver  16 . In this way, the correct position of the test strip  18  in the strip receiver  16  is established, in which correct position the test field  30  is located exactly over the measuring opening  28 . Because of the bending of the test strip and because of the stiffness of the strip material, a restoring force is created in the strip which presses the test field  30  firmly against the support surface  26  so that the test field  30  has a definite spacing from the measuring optic  22 . As will be recognized, the test strip  18  can be inserted in simple way into the strip receiver  16  and, above all, can be again pulled out of the strip receiver in a simple way, without this simple operation encumbering the positioning accuracy. 
     The solution illustrated in  FIGS. 2 and 3  differ from the  FIG. 1  solution in the way the test strip is held in the measuring device. The same or equivalent parts are again provided with the same reference numbers as in  FIG. 1 . 
     In the solution illustrated in  FIG. 2 , the counter-pressure surface  36  is omitted. In place of it, a lid-like two-armed lever  46  with a clamping arm  48  and an actuating arm  50  is pivotally supported by the side walls  42  bordering the support surface  26  of the carrier  24  for pivotal movement about a pivot axis  44 . The spring arm  34  lies on the actuating arm  50  and biases the lever  46  in the clock-wise direction so that the clamping arm  48  is pressed toward the support surface  26 . If, as shown in  FIG. 2 , a test strip  18  is inserted into the strip receiver  16 , the test strip  18  at its forward section is pressed against the support surface  26  by the clamping arm  48 . The position of the test strip  18  is established by a nose  52  on the lower side of the clamping arm which is receivable in a detent recess  38  of the test strip  18 . In this position of the test strip  18 , the test field  30  is located exactly over the measuring opening  28 . This embodiment is especially simple to operate. For insertion and removal of the strip  18 , the actuating arm  50  of the lever  46  is pressed downwardly; that is, the lever  46  is pivoted in the counter-clockwise direction. For removal of the test strip  18 , it is sufficient, at this moment, to hold the device downwardly, so that the test strip  18  falls by itself out of the device. The operating person need not again touch the used test strip. 
     In a variant of the embodiment illustrated in  FIGS. 2 and 3 , the support surface  26 , in which the measuring opening  28  is formed, is entirely flat and smooth. To make possible an insertion of the test strip  18 , the clamping arm  48  of the clamping lever  46  has, as seen in  FIG. 13 , on its side facing the support surface  26  a groove shaped recess  47  in which the test strip  18  is conformably received. The edge flanges  49  of the clamping arm  48  bordering the recess  47  are received in complementary recesses of  51  in the carrier  24  to prevent a lateral shifting of the clamping arm  48  and test strip  18  and to assure a better guiding of the test strip  18 . 
     In  FIG. 4  the strip receiver  16  is shown only schematically with one recognizing the support surface  26 , the side wall  54  bordering the support surface  26 , and the forward wall  56 . In the strip receiver  16  is a test strip  18 . This test strip has on its end near the forward wall  56  of the strip receiver  16  a recess  58  extending nearly over the entire strip width, so that at the forward end of the test strip  18  only a small material bridge  60  remains. At the forward wall is formed a projection  62  which presses against the material bridge  60  of the test strip and slightly deforms the bridge. By the restoring force produced in this way, the test strip is pressed rearwardly in the direction of the arrow B so that its two step surfaces  64  engage two abutment surfaces  66  formed at the insertion end of the strip receiver  16 . For insertion, the test strip  18  is pushed into the strip receiver  16  so that the material bridge  60  at the forward end of the test strip is slightly deformed. Then the test strip is pressed against the support surface  26  and let loose so that its step surfaces  64  come to lie onto the abutments  66 . A reverse procedure is used for removal. One grasps the test strip at its grip end  68  and lifts it slightly upwardly so that the step surfaces  64  are freed from the abutments  66 . This solution also guarantees a correct positioning of the test strip on the support surface  26  so that the test field  30  comes to lie over the measuring opening  28  indicated by the dashed lines. 
     The embodiment, according to  FIG. 5 , functions according to the same principle as the embodiment of  FIG. 4  with the recesses in the test strip  18  producing the spring effect being formed solely by lateral slots  70 . In this case, spring tongues  72  exist at the forward end of the test strip  18  which upon their being pressed against the stepped forward wall  56  of the strip receiver  16  produce a restoring force by means of which the test strip  18  is consequently pushed to bring its step surfaces  64  against the abutments  66 . 
     In the illustrated embodiment of  FIG. 6 , at the forward area of the test strip  18 , near the longitudinal edges of the test strip, two slots  74  are provided which form lateral material bridges  76 . These material bridges each have at their outer sides a detent nose  78  intended for reception in a complementary detent recess  80  in the side wall  54  of the test strip receiver  16 . The dimensions of the noses and the width of the test strip  18  are so-chosen that the noses  78  upon insertion of the test strip  18  into the strip receiver  16  are slightly pressed together and then, upon reaching the detent recesses  80 , spring outwardly. In this way, the test strip  18  is held in its measuring position. 
     In the embodiment according to  FIG. 7 , a spring  82  is arranged at the inner end of the strip receiver, which spring presses against the forward end of the test strip  18  and tends to push the test strip out of the strip receiver in a direction opposite to the insertion direction; that is in the direction of the arrow B. The test strip  18  has at each of its longitudinal edges a notch  84  intended for receiving an arresting element  86 . The arresting element  86  is arranged in the strip receiver  16  and is movable between the arresting or receiving position illustrated in  FIG. 7  and a freeing position. In the arresting position of  FIG. 7 , the elements  86  hold the test strip  18  firmly in the strip receiver and assure, in cooperation with the spring  82 , a precise positioning of the test strip  18  inside of the strip receiver  16 . When the arresting elements  86  are pressed outwardly into their freeing positions, the spring  82  pushes the test strip  18  out of the strip receiver  16 , and the test strip  18  can fall out of the device without the operating person having to again touch the strip. 
     The embodiment of  FIG. 8  differs from that of  FIG. 7  only in that, instead of two locking elements  86 , a centrally-arranged locking element is provided which can be received in a corresponding central recess  84  in the test strip  18 . In both embodiments, one will recognize that a test strip can only be inserted into the strip receiver  16  if it has the detent recesses or recess at a definite pre-given place. Otherwise, the spring  82  constantly pushes the test strip  18  out of the receiver. In principle, a number of locking elements can be provided at different positions in the test receiver while the test strip has only one recess corresponding to one of these locking elements, so that the test strip can be quasi-coded by the arrangement of the recess. 
       FIG. 10  shows an embodiment of the strip receiver in which the carrier  24  has a holding bar  88  at its inner end under which the forward end of the test strip  18  is insertable. A detent nose  90  is formed on the inner or underside of the holding bar  88  which nose is receivable in a corresponding detent opening  92  in the test strip  18  with which it fixes the test strip in a definite position. 
     The measuring opening  28  is surrounded on the upper side of the support surface  26  by a ring  94  which lifts the test strip  18  slightly above the support surface  26 . Near the insertion end of the strip receiver  16 , two noses  96  and  98  are formed on the side walls  54  of the strip receiver  16 , under which noses the associated edges of the test strip  18  can be inserted. The form of the detent noses  96  and  98  is illustrated in cross-section in  FIGS. 11 and 12 . Naturally, both detent noses can have the same form. As seen in  FIG. 10 , by the reception of the test strip under the bar  88 , on one hand, and under the noses  96  and  98 , on the other hand, the test strip  18  is bent over the ring  94  so that the test field  30  lies securely and flatly on the ring  94  and, therefore, has a definite spacing relative to the measuring optic lying beneath the opening  28 . (Note: nose  98  is not shown in the sectional view of  FIG. 10 ). 
     In the previously-described embodiments, it has always been presumed that the test field is to be measured by a measuring optic of the measuring device.  FIG. 14  shows, in a schematic illustration corresponding to  FIG. 2 , an embodiment of the inventive measuring system by means of which the test field on the test strip  18  can be measured by way of electrical current. Similar parts are again provided with similar reference numbers. 
     Instead of a measuring optic, contact springs  100  are arranged on the plate  20 , which, for one thing, are intended to come into contact with non-illustrated counter-contact elements on the test strip  18  when the test strip  18  is in its measuring position in the measuring device  10 . For another thing, the contact springs  100  are so-formed that they urge the test strip  18  in its measuring position against the support surface  26 . 
     The lever  46  serves in the  FIG. 14  embodiment to lift the contact springs  100  from the contact elements of the test strip  18  and thereby to simultaneously free the test strip  18  so that it can fall out of the measuring device  10  when the measuring device is held with its insertion opening facing downwardly. Instead of the clamping arm  48 , the lever  46  in this embodiment has a daw  102  which extends around the free ends of the contact springs  100  so that by the pivoting of the lever  46  in the counter-clockwise direction of  FIG. 14 , the contact springs  100  are lifted from the support surface  26  and from the test strip  18 . The lever  46  can, as in the embodiment of  FIGS. 2 and 3 , be returned to its original position by the spring arm  34 . As the case may be, the spring effect of the contact springs  100  may also be sufficient for this purpose. The measuring area of the measuring device  10 , illustrated in  FIG. 14 , is closed by a cover  104  which has only one opening  106 , through which the lever  46  can be actuated.