Abstract:
An injection device has a housing ( 38 ) having a housing wall and having a first window ( 50 ) provided therein. Arranged rotatably in the housing ( 38 ) is a graduation carrier ( 60 ) on which are arranged, in helical fashion, dose values ( 62 ′) that are at least partly visible through the first window ( 50 ). A second window ( 54 ) is located in the housing ( 38 ) and is arranged displaceably in the longitudinal direction of the housing ( 38 ), a rotary motion of the graduation carrier ( 60 ) being synchronized with a longitudinal displacement of the second window ( 54 ) in order to indicate, through the first window ( 50 ) and the second window ( 54 ), the injection dose value ( 62 ′) that is presently selected. Since the selected dose value ( 62 ′) is only legible when viewed through both lenses ( 80,90 ), this militates against incorrect readings of the selected dose setting.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present application is a section 371 of PCT/EP09/05123, filed 15 Jul. 2009, which in turn claims priority from German application DE 20 2008 011 175.7, filed 18 Aug. 2008, the disclosure of which is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to an injection device that is equipped with an apparatus for indicating an injection dose that has been set. 
       BACKGROUND 
       [0003]    Ambiguous indications must not occur with such injection devices, since injection devices are often used by persons with poor vision, for example by diabetics, for whom an unequivocal display is extremely important, in order to avoid improper operation. 
       SUMMARY OF THE INVENTION 
       [0004]    It is therefore an object of the invention to make available a novel injection device which militates against improper operation. 
         [0005]    According to the invention, this object is achieved by equipping the injection device with a housing having a first window therein, a graduation carrier bearing dose values arranged on its surface in a helical configuration, a longitudinally displaceable second window in the housing, and respective lenses in the first and second windows, such that the first lens by itself distorts the dose values but the first and second lenses interact to render a single dose value legible, thereby militating against incorrect readings of the dose value selected by the user. Only at the point, where the first transparent lens arrangement and the second transparent lens arrangement interact, is it possible for a readily legible display, of the dose that has been set, to be visible; whereas at points where only the first transparent lens arrangement, but not the second, is effective, the visible, but optically distorted, dose values do not permit a legible reading, and thereby militate against improper settings of the injection dose. 
     
    
     
       BRIEF FIGURE DESCRIPTION 
         [0006]    Further details and advantageous refinements of the invention are evident from the exemplifying embodiment, in no way to be understood as a limitation of the invention, that is described below and depicted in the drawings. 
           [0007]      FIG. 1  shows an example of an injection device in which the invention can be utilized; 
           [0008]      FIG. 2  shows the injection device of  FIG. 1 , on the left after an injection, on the right after an injection dose of 40 units has been set and prior to an injection; for a better comparison, the effect of the lens arrangement described here is depicted only in  FIG. 2   b , but not in  FIG. 2   a;    
           [0009]      FIG. 3  presents three depictions of a housing part  38 , used in the context of  FIGS. 1 and 2 , having a first window  50  that has a function in the context of indication of the injection dose that has been set;  FIG. 3   a  is a plan view looking in the direction of an arrow IIIa of  FIG. 3   b ;  FIG. 3   b  is a section viewed along line IIIb-IIIb of  FIG. 3   a ;  FIG. 3   c  is a plan view of the window side looking in the direction of an arrow IIIc of  FIG. 3   b;    
           [0010]      FIG. 4  is a perspective depiction of an inner sleeve used in the context of  FIGS. 1 and 2 , having a second window that likewise has a function in the context of indication of the injection dose that has been set; 
           [0011]      FIG. 5  depicts the setting sleeve used in the context of  FIGS. 1 and 2 , which carries indicia that serve to indicate the injection dose that has been set; 
           [0012]      FIG. 6  depicts the upper part of the injection device of  FIG. 1 ; 
           [0013]      FIG. 7  is a plan view of a first dispersing panel that, according to  FIG. 6 , is inserted into the first window of housing  38 , viewed in the direction of arrow VII of  FIG. 8 ; 
           [0014]      FIG. 8  is a section viewed along line VIII-VIII of  FIG. 7 ; 
           [0015]      FIG. 9  is a plan view of a second dispersing panel that is inserted into second window  54  and interacts with the first dispersing panel; 
           [0016]      FIG. 10  is a section viewed along line X-X of  FIG. 9 ; 
           [0017]      FIG. 11  is a depiction analogous to  FIG. 6 ; and 
           [0018]      FIG. 12  is a section viewed along line XII-XII of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]      FIG. 1  is a side view of an injection device  30 . This example refers to a so-called semiautomatic unit, i.e. the patient sets the desired injection dose by rotation  32  of a setting knob  34 , as shown by a comparison of  FIG. 2   a  (before setting) and  FIG. 2   b  (after setting). A length L, by which a piston rod  36  projects out of a housing part  38 , does not change in this context. Piston rod  36  has, at its lower end, an enlargement  40  with which it abuts against a rubber piston  42  that is arranged displaceably in a glass cartridge  44  in which injection fluid  46  is present. Glass cartridge  44  is located in a lower (proximal) housing part  45  that is screwed by means of a thread  39  ( FIG. 3 ) onto upper housing part  38 . An injection needle  48  ( FIG. 1 ) is mounted on the lower portion of housing part  45  prior to an injection. 
         [0020]    The terms “proximal” and “distal” are used in the manner that is usual in medicine, i.e. proximal=close to the patient (the end having needle  48 ), distal=away from the patient (the end having setting knob  34 ). 
         [0021]    Upper housing part  38  has a first window  50  ( FIG. 1 ) for setting an injection dose. A cylindrical inner sleeve  52  ( FIG. 4 ) is arranged axially displaceable in upper housing part  38 . Said sleeve has a second window  54  having an upper axial delimiter  56  away from the patient, and a lower axial delimiter  58  close to the patient. Inner sleeve  52  further has, on its outer side, axially extending ribs  59  that serve for axial guidance in corresponding inner grooves  62  ( FIG. 3 ) of upper housing part  38 . 
         [0022]    Upper delimiter  56  acts as a stop for the maximum dose, which here is equal to approximately 60 units; and lower delimiter  58  acts as a stop for the zero dose, which is reached automatically after an injection. (This is depicted in  FIG. 1 .) Any intermediate positions are possible between these extreme values, i.e. 0 units and 60 units. A dose that was originally set and was too high can also be corrected by the patient. 
         [0023]      FIG. 5  shows graduated tube  60  on which is located scale  62 ′ having values  63  settable by the patient. These are arranged helically on the outer side of graduated tube  60 . The latter is not axially displaceable relative to upper housing  38  but is rotatable, so that by means of setting knob  34  and a coupling (not depicted), it can be rotated relative to upper housing part  38 . Graduated tube  60  has, on its outer side, an external thread  64  that is in engagement with an internal thread  66  of inner sleeve  52 . 
         [0024]    When graduated tube  60  is rotated by means of setting knob  34 , it therefore brings about, using the two threads  64 ,  66 , an axial displacement of inner sleeve  52  and thus of second window  54 , specifically synchronously with the rotation of graduated tube  60 , so that each dose indication of graduated tube  60  corresponds to a specific axial position of second window  64  relative to first window  50 . An unequivocal dose indication thus results with this embodiment, since only the dose quantity, that is set, can be read in window  54 . 
         [0025]    If threaded sleeve  52  is short for design-related reasons, it may cover not the entire graduated tube  60  but only its upper part, as depicted in  FIG. 1 . The lower part of graduated tube  60 , however, remains visible as depicted in  FIG. 2   b ; this might confuse some patients. 
         [0026]    This is because, in certain cases, the overall length of injector  30  must be minimized, so that the length of inner sleeve  52  (having window  54 ) cannot cover scale  62 ′ on its proximal region close to the patient. If this were the case, then in fact only the dose that has been set would be visible in window  54 . For space reasons, however, this is not possible (see  FIG. 2   b ). 
         [0027]    This problem is solved by using housing part  38  having said first window  50 , in which inner sleeve  52  having second window  54  is arranged in longitudinally displaceable fashion. Window  54  has an upper delimiter  56  and a lower delimiter  58 . Indicator arrows  55 ,  57  that indicate the injection dose that has been set (see  FIG. 2   a ) can be located on both delimiters. 
         [0028]    Because the proximal part of scale  62 ′ on graduated tube  60  can no longer, because of the minimized length of inner sleeve  52 , be completely covered upon axial displacement of inner sleeve  52  in a distal direction, not only the dose that has been set, but instead all the numbers of scale  62 ′, would be visible in the proximal region, close to the patient, of first window  50 , since they are no longer concealed by inner sleeve  52 . 
         [0029]    For patients with poor vision, for example diabetics, this leads to the risk of misreading, i.e. in the case of, for example, the dose setting in accordance with  FIG. 2   b , a patient with poor vision might read off not the dose of 40 units that is set, but the value of 20 units or a value of 0, which might cause him or her to set an incorrect injection dose. 
         [0030]    Such problems can be avoided with the configuration according to  FIGS. 6 to 12 . 
         [0031]    Here a first lens system  80 , depicted in  FIG. 7  and  FIG. 8 , is inserted into first window  50 . Said system has the properties of a dispersing panel, i.e. prevents the patient from making incorrect readings through said first lens system  80 . 
         [0032]    As  FIGS. 7 and 8  show, here the first transparent lens arrangement  80  is inserted into window  50 , for example, by being clipped or adhesively bonded. 
         [0033]    As  FIG. 8  shows, lens  80  has in cross section a profile that is smooth on upper side  82 , e.g. in the shape of a cylindrical surface or even a flat surface (not depicted). On lower side  84 , facing away from upper side  82 , lens  80  has a profile with elevations  86  and depressions  88  proceeding in a longitudinal direction. As a result, when lens  80  is used alone it acts as a dispersing panel, i.e. it is not possible to legibly read numbers  62 ′ of graduated tube  60  through said lens  80 . 
         [0034]      FIG. 9  and  FIG. 10  show a corresponding configuration of a second transparent lens arrangement  90  that is implemented to interact with lens arrangement  80  (see  FIG. 12 ). 
         [0035]    Arrangement  90  is inserted into window  54  of inner sleeve  52 , for example by being clipped or adhesively bonded in. Its lower side  92  is cylindrical or flat (not depicted), and its upper side has valleys  94  extending in a longitudinal direction and longitudinal ridges  96 , which extend in complementary fashion to elevations  86  and depressions  88  of  FIG. 8 , so that first lens arrangement  80  and second lens arrangement  90 , when they are arranged one above another with a spacing as depicted in  FIG. 12 , together form a lens arrangement  100 . 
         [0036]    Second lens arrangement  90  is displaceable in a longitudinal direction relative to first lens arrangement  80 , so that the visible region within second window  54  migrates axially when graduated tube  60  is rotated for dose setting purposes. In this manner, only the dose value that is presently set can be read clearly, as depicted by way of example in  FIG. 2   b  but not in  FIGS. 1 and 2   a.    
         [0000]    (Be it noted, in this connection, that this optical effect is difficult to depict graphically.) 
         [0037]    This improved legibility is achieved by the interaction of lens arrangement  100  with a mechanical setting apparatus. Incorrect settings are thereby reliably avoided, resulting in a readily understandable mode of operation. 
         [0038]    Numerous variants and modifications are of course possible within the scope of the present invention. For example, inner sleeve  52  can likewise be made of transparent plastic, and can be formed integrally with second lens arrangement  90 . It is particularly advantageous that, in the version according to  FIGS. 7 to 12 , inner sleeve  52  can be short (see  FIG. 4 ). 
         [0039]    Numerous variants and modifications are of course possible, within the scope of the present invention.