Abstract:
In an elongated casing, an active agent container connected to an injection needle can be shifted axially by a spring force. Auto-injectors which are sold or distributed filled and with the springs tensed have to be provided with a needle protecting cap to ensure the sterility of the injection needle. When such a needle protecting cap is removed as preparation for using the auto-injector, a tensile force can be exerted on the active agent container. Therefore, the active agent container comprising the injection needle must be prevented from being undesirably pulled forwards. At least one latching tongue prevents the active agent container from being prematurely shifted with respect to the casing, by abutting a flange arranged on a sliding sleeve which accommodates the active agent container. When the auto-injector is placed onto a person&#39;s skin, a needle protecting tube is shifted into the casing, forcing the latching tongue away from the flange and, thus, freeing the travel path for needle movement.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 13/854,425 filed Apr. 1, 2013, which is a continuation of U.S. application Ser. No. 11/836,503 filed on Aug. 9, 2007 and issued as U.S. Pat. No. 8,409,149 on Apr. 2, 2013, which is a continuation of U.S. application Ser. No. 11/016,539 filed on Dec. 17, 2004 and issued as U.S. Pat. No. 7,357,790 on Apr. 15, 2008, which claims priority to Swiss application No. CH 2186/03, filed on Dec. 18, 2003, the entire contents of all of which are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND 
       [0002]    The invention relates to devices and methods for the administration or delivery of substances, including the administration of medicinal substances to patients. More particularly, it relates to injection or infusion devices and methods, and to an auto-injector for automatically injecting an active agent. In one embodiment, the auto-injector comprises an elongated casing, an injection needle which can be shifted axially in the casing and is connected to an active agent container, a piston which can be shifted in the active agent container for the purpose of delivering the active agent, and a needle protecting tube which can be shifted relative to the casing. 
         [0003]    Auto-injectors are known in many different embodiments. They serve to administer injections, in particular by a patient him or herself. When used, an injection needle is automatically inserted, in the majority of cases by means of a spring force, and then an active agent is injected. Many reusable auto-injectors are known and also those which, once used, are partially or completely thrown away. Auto-injectors which are sold or distributed filled and with the springs tensed have to be provided with a needle protecting cap in order to be able to ensure the sterility of the injection needle. Since this needle protecting cap preferably encloses the active agent container connected to the injection needle, forming a seal, a certain tensile force is necessarily exerted on the active agent container as the needle protecting cap is removed in preparation for using the auto-injector. 
       SUMMARY 
       [0004]    In one embodiment, the present invention addresses the object of preventing an active agent container, comprising an injection needle, from being undesirably moved, e.g., pulled forward, for example when removing a needle protecting cap. 
         [0005]    This object is addressed in accordance with one embodiment of the invention by providing an injection device with a latching member that, in a latching position, prevents the active agent container from being shifted with respect to the casing of the device, and by providing that the latching member can be moved to a release position, in which it allows the active agent container to be shifted with respect to the casing, by shifting a needle protecting tube into the casing. In one embodiment, the latching member is preferably fixed and/or locked in the latching position by the needle protecting tube. 
         [0006]    In one embodiment, the present invention comprises an automatic injection device comprising an elongated casing, and an active agent container connected to an injection needle, wherein the container can be shifted axially by a spring force. Such auto-injectors which are sold or distributed filled and with the springs tensed have to be provided with a needle protecting cap to ensure the sterility of the injection needle. When such a needle protecting cap is removed as preparation for using the auto-injector, a tensile force can be exerted on the active agent container. Therefore, the active agent container comprising the injection needle should be prevented from being undesirably pulled forwards. At least one latching tongue prevents the active agent container from being prematurely shifted with respect to the casing, by abutting a flange arranged on a sliding sleeve which accommodates the active agent container. When the auto-injector is placed onto a person&#39;s skin, a needle protecting tube is shifted into the casing, forcing the latching tongue away from the flange and, thus, freeing the travel path for needle movement. 
         [0007]    The present invention not only has the advantage that the active agent container remains in position in the auto-injector when the needle protecting cap is removed, but also that the auto-injector is prevented from being intentionally or unintentionally triggered until the needle protecting tube has been shifted into the casing. 
         [0008]    In accordance with a preferred embodiment of the invention, the latching member is formed as at least one elastically flexible latching tongue. The tongue can be arranged on the casing itself or, in some preferred embodiments, on a latching sleeve mounted in the casing and formed integrally with the latching sleeve. These measures make it easier to manufacture the components from plastic in an injection moulding process, but alternatives exist, including forming the tongue and sleeve separately and then operably coupling them. 
         [0009]    In one embodiment, the latching member preferably prevents the active agent container from being shifted with respect to the casing by abutting a flange arranged on a sliding sleeve which accommodates the active agent container. As it is shifted into the casing, the needle protecting tube forces the latching member away from said flange. This design is simple and operationally reliable. 
         [0010]    In accordance with another preferred embodiment of the invention, the latching member comprises a surface which runs or extends obliquely with respect to the longitudinal axis of the auto-injector and abuts a surface, likewise running or extending obliquely with respect to the longitudinal axis of the auto-injector, on the sliding sleeve which accommodates the active agent container. In some embodiments, the oblique surfaces of the latching member and the sliding sleeve ideally run parallel to each other. In some preferred embodiments, the oblique surfaces are each arranged on facing sides of the latching member and the sliding sleeve, such that the tip of the oblique surface of the latching member is provided on a surface of a latching sleeve, the surface pointing outwards from the auto-injector. 
         [0011]    In the latching position, the oblique surfaces abut each other and the latching member is held in this position by the needle protecting tube. When the needle protecting tube is shifted into the casing, the latch is released. As soon as pressure is exerted on the sliding sleeve, so as to advance the active agent container comprising the needle for injecting, the oblique surface of the latching member slides outwardly along the oblique surface of the sliding sleeve, such that the sliding sleeve can be advanced. The latching member is therefore moved or forced out of the latching position by the sliding sleeve. 
         [0012]    In accordance with another embodiment of the invention, a needle protecting cap is provided which preferably fulfils a double function in that it prevents the needle protecting tube from retracting into the casing when it is placed on the auto-injector. To this end, the needle protecting cap preferably comprises an inner sleeve reaching over the active agent container and an outer sleeve reaching over the needle protecting tube. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    (Each of the first seven figures depicts a longitudinal section through one embodiment of an auto-injector in accordance with the present invention, wherein a different operational state is depicted in each figure). 
           [0014]      FIG. 1  depicts the condition on delivery; 
           [0015]      FIG. 2  depicts the state in which the auto-injector is unlocked; 
           [0016]      FIG. 3  depicts the state in which the auto-injector is placed on the point of injection; 
           [0017]      FIG. 4  depicts triggering; 
           [0018]      FIG. 5  depicts the end of injecting; 
           [0019]      FIG. 6  depicts the end of delivering the active agent; 
           [0020]      FIG. 7  depicts the state once used; 
           [0021]      FIG. 8  depicts another embodiment of an auto-injector in accordance with the invention, in the latching position; 
           [0022]      FIG. 9  depicts the auto-injector embodiment of  FIG. 8  in a releasing position; 
           [0023]      FIG. 10  depicts the auto-injector embodiment of  FIG. 8  in a position in which the needle has been injected; and 
           [0024]      FIG. 11  depicts the auto-injector embodiment of  FIG. 8  in a locking position in which the needle protecting tube is latched. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    The drawings depicts one exemplary embodiment of an auto-injector in accordance with the present invention. The depicted auto-injector has a casing “C” comprised of a front casing part  1  and a rear casing part  2 , wherein the two casing parts are joined together by a connection  3 . If the auto-injector is a refillable auto-injector, the connection  3  is releasable, for example, it may comprise a threaded connection. If, however, the auto-injector is a disposable, the connection  3  can be fixed, for example, by a fused connection, adhesive connection or latching connection. On the left in the figures, a needle protecting tube  4  can be seen which can be shifted axially in the front casing part  1 , as will be described in more detail below. A sliding sleeve  5  which can be shifted axially is guided in the needle protecting tube  4  via its front end and in the front casing part  1  via a flange  6  formed on its rear end. The sliding sleeve  5  accommodates an ampoule-like active agent container  7 , in the interior of which a piston  8  can be shifted axially with the aid of a piston rod  9 , for the purpose of delivering the active agent. At its front end, the active agent container  7  is provided with an injection needle  10 . 
         [0026]    A locking member in the form of a locking sleeve  24  is mounted externally on the sliding sleeve  5 . At least one locking tongue  25  protrudes elastically outwards from the locking sleeve  24  and in the operational state in accordance with  FIG. 1  abuts an inner heel  27  of the needle protecting tube  4 . A cavity  26  which is formed in the needle protecting tube  4  and into which the locking tongue  25  protrudes is connected to the heel  27 . The function of the locking sleeve  24  and the locking tongue  25  will be set forth further below. A guiding sleeve  11  is arranged in the rear casing part  2 , such that it can be shifted axially. A driving part  12 , which protrudes backwards out of the guiding sleeve  11  and abuts an end flange of the guiding sleeve  11  via latching projections  13 , is situated in the guiding sleeve  11 . The driving part  12  contacts the piston rod  9  and is biased against it by a driving spring  14 . 
         [0027]    In  FIG. 1 , the auto-injector is depicted in its latched position. This position is useful for the delivery, shipment, sale or storage of the auto-injector since it secured against being intentionally or unintentionally activated and is protected from contamination. A needle protecting cap  15  on the side of the injection needle  10  serves this purpose and has an outer sleeve  16  reaching over the front casing part  1  and the needle protecting tube  4  and an inner sleeve  17  reaching over the injection needle  10  and the front end of the active agent container  7  which encloses it, forming a seal, and thus ensures that the injection needle  10  is clean and sterile. In addition, the attached needle protecting cap  15  also secures the auto-injector against being intentionally or unintentionally triggered, by preventing the needle protecting tube  4  from being touched or shifted. 
         [0028]    A securing cap  18 , which comprises a securing pin  19  in its centre, is placed on the rear end of the auto-injector, on the right in the figures. The securing pin  19  protrudes between the latching projections  13  of the driving part and thus reliably prevents an injection from being triggered. In order to prepare the auto-injector for use, the needle protecting cap  15  and the securing cap are removed. It is clear that when the needle protecting cap  15  is removed, a tensile force is exerted on the active agent container  7  as a result of the static friction between the inner sleeve  17  and the active agent container  7 . Consequently, the active agent container  7  must be prevented from leaving its position (e.g., being undesirably moved or pulled forward) in the auto-injector when the needle protecting cap  15  is removed. 
         [0029]    For this purpose, a latching sleeve  20  is mounted in the front casing part such that it cannot move axially and at least one latching tongue  21  is arranged on the latching sleeve  20 . Three latching tongues  21  are preferably provided in one embodiment, arranged or distributed symmetrically around the circumference of the latching sleeve. As  FIG. 1  clearly shows, the free end of the latching tongue  21  abuts the flange  6  of the sliding sleeve  5  and thus prevents the sliding sleeve  5  from being pulled forwards together with the active agent container  7  arranged in it. 
         [0030]      FIG. 2  shows the auto-injector after the needle protecting cap  15  and the securing cap  18  have been removed as described above. The latching member  20  is still in the latching position and the latching tongue  21  prevents the active agent container  7 , comprising or carrying the injection needle  10 , from being slid forward. In addition, at the then open end, the needle protecting tube  4  creates a distance which prevents the injection needle  10  from being touched or at least makes it difficult to touch the injection needle  10 . The needle protecting tube  4  is held in this position by the force of a spring  22  which is clamped between the rear end of the needle protecting tube  4  and the rear casing part  2 . 
         [0031]      FIG. 3  shows the auto-injector in a position which it assumes when it is pressed onto the skin of a patient but has not yet been triggered. The needle protecting tube  4  has been shifted backwards into the casing as compared to the position of  FIG. 2 , compressing the spring  22 , such that the tip of the injection needle  10  is then situated slightly above the skin of the patient.  FIG. 3  also shows that the needle protecting tube  4  shifted backwards has forced the latching tongue  21  outwards, which then exposes the flange  6  of the sliding sleeve  5 . As compared to  FIG. 2 , it can be seen that a flange  23  formed internally in the rear part of the needle protecting tube  4  then abuts the front facing side of the guiding sleeve  11 . It should be noted that the needle protecting tube still protrudes out of the front casing part  1  by a remaining amount at the front. However, as compared to  FIGS. 1 and 2 , it should be clear that the needle protecting tube  4  has slid the locking sleeve  24  some distance backward on the sliding sleeve  5 . 
         [0032]      FIG. 4  shows the auto-injector at the moment of triggering. Proceeding from the state depicted in  FIG. 3 , the user has pressed the auto-injector slightly harder onto the skin, such that the needle protecting tube  4  has been shifted into the casing by the remaining amount mentioned above, wherein the flange  23  has shifted the guiding sleeve  11  backwards in the rear casing part  2  by the remaining amount and the latching projections  13  have been moved into the region of a triggering ring  28  arranged in the rear end of the rear casing part  2 . The triggering ring  28  has contacted and/or pressed the latching projections  13 , formed on elastic arms of the driving part, far enough against each other that they are then pulled through the end opening of the guiding sleeve  11  by the force of the driving spring  14 . The force of the driving spring  14  then acts, unobstructed, on the piston  8  via the piston rod  9 , the piston  8  in practice abruptly increasing the hydraulic pressure in the active agent container  7 . This pressure slides the active agent container forwards, such that the injection needle  10  penetrates into the skin of the patient. Since the diameter of the passageway in the injection needle  10  is comparatively small, at most a very small amount of the active agent can exit the injection needle  10  in this short period of time between triggering and the injection needle  10  penetrating into the skin. 
         [0033]    The injection stroke is complete when the flange  6  of the sliding sleeve  5  abuts the end of the needle protecting tube  4  and/or the end of the locking sleeve  24 .  FIGS. 5 and 6  show the auto-injector in the position in which the injection needle  10  is inserted or injected, wherein  FIG. 5  shows the operational state at the beginning of delivering the active agent and  FIG. 6  shows the state of the auto-injector after the active agent container  7  has been completely emptied. When the operational state in accordance with  FIG. 6  has been reached, the user retracts the auto-injector in order to remove the injection needle  10  from his skin. 
         [0034]      FIG. 7  shows the operational state after the injection needle  10  has been removed from the skin of the patient. The needle protecting tube  4  was shifted back into its initial state by the force of the spring  22  as soon as the auto-injector was lifted from the skin of the patient. It then mainly serves to substantially cover the injection needle and protect the user and other persons from injuries from the injection needle  10 . Consequently, the needle protecting tube  4  must be prevented from being shifted relative to the injection needle  10  such that the injection needle  10  protrudes out of the needle protecting tube  4 . This task is accomplished by the locking tongue  25 , which is formed in the locking sleeve  24 . While the needle protecting tube  4 , as mentioned, has been shifted forwards by the spring force, the locking sleeve  24  maintains its position on the sliding sleeve  5  as a result of a latch tongue  29  formed on the sliding sleeve  5 , which then protrudes into a cavity of the locking sleeve  24  in the position in accordance with  FIG. 7  and thus fixes it in place on the sliding sleeve  5 . 
         [0035]    As can clearly be seen in  FIG. 7 , the free end of the locking tongue  25  at the rear end of the needle protecting tube  4  then protrudes into its path. Thus, the needle protecting tube  4  cannot be retracted without the locking sleeve  24 , the sliding sleeve  5  and the active agent container  7  together with the injection needle  10 , being shifted backwards relative to the front casing part  1  and the rear casing part  2 , against the force of the driving spring  14 . Thus, the injection needle  10  maintains its relative position with respect to the needle protecting tube  4  and the injection needle  10  and is reliably prevented from being intentionally or unintentionally touched. This solution has the advantage that the axially directed force to be absorbed by the locking tongue  25  never exceeds the force of the driving spring  14 , irrespective of how hard one presses against the front end of the needle protecting tube  4 . 
         [0036]      FIGS. 8 to 11  show another embodiment of an auto-injector in accordance with the present invention. In these figures, identical elements and elements having substantially the same function are denoted using the reference numerals from  FIGS. 1 to 7 . In this embodiment, the latching tongue  21  is guided by means of surfaces on the latching tongue  21  and the sliding sleeve  5 , the surfaces running or extending obliquely with respect to the longitudinal axis of the auto-injector. The latching tongue  21  for latching the active agent container or the sliding sleeve  5  and the locking tongue  25  for latching the needle protecting tube  4  are also both arranged on the latching sleeve  20 . In some preferred embodiments, the latching tongue  21  and the locking tongue  25  are formed integrally with the latching sleeve  20 . In some embodiments, multiple latching tongues  21  and locking tongues  25  can be provided on the latching sleeve  20 . 
         [0037]      FIG. 8  shows a latching member in the form of a latching sleeve  20  which comprises a latching tongue  21  which comprises a surface  30  running or extending obliquely with respect to the longitudinal axis of the auto-injector, on its facing side. The tip of the oblique surface  30  abuts the outer side of the latching tongue  21 . The sliding sleeve  5  comprises a cavity  31  into which the latching tongue  21  protrudes in the latching position. The edge of the cavity  31  opposite the oblique surface  30  of the latching tongue  21  comprises an oblique surface  30 ′ which runs or extends generally parallel to the oblique surface  30  of the latching tongue  21 . (In some embodiments, an oblique surface could be provided directly on the active agent container  7 , such that the sliding sleeve  5  can be omitted.) The two oblique surfaces  30  and  30 ′ come to rest on each other. The needle protecting tube  4  is at least partially arranged between the latching sleeve  20  and the sliding sleeve  5 , wherein the latching tongue  21  protrudes through a cavity in the needle protecting tube  4  into the cavity  31  of the sliding sleeve  5 . A part  32  of the needle protecting tube  4  overlaps the abutting point of the oblique surfaces  30  and  30 ′, such that the latching tongue  21  is locked in the latching, latched or lacked position. In  FIG. 8 , a locking tongue  25  is also arranged on the sliding sleeve  5 , on the side opposite the latching tongue  21 . The locking tongue  25  protrudes into a cavity opposite it, in the needle protecting tube  4 . 
         [0038]      FIG. 9 , generally analogous to  FIG. 3 , shows the auto-injector in a release position in which the needle protecting tube  4  is slid into the casing “C”. In this position, the part  32  of the needle protecting tube  4  has been retracted from the overlapping area of the oblique surfaces  30  and  30 ′. The latching tongue  21  can then be moved into the cavity  31  of the needle protecting tube  4 . The movement can be caused by a bias on the elastic latching tongue  21 . In some preferred embodiments, however, the latching tongue  21  is slid outwards into the cavity by the pressure exerted by the driving spring  14 , which acts on the oblique surface  30 . 
         [0039]      FIG. 10 , generally analogous with  FIG. 5 , shows the auto-injector in a position in which the active agent container  7  is advanced relative to the casing “C” and the injection needle  10  is injected into a tissue. The sliding sleeve  5  has been advanced together with the active agent container  7  in a distal direction along the latching sleeve  20 , wherein the latching tongue  21  comes to rest in the cavity  31  of the needle protecting tube  4 . 
         [0040]      FIG. 11 , generally analogous with  FIG. 7 , shows the auto-injector in a position in which the needle protecting tube  4  surrounds the injection needle  10  after the auto-injector has been removed from the surface of the tissue. In this embodiment, the locking tongue  25  is likewise arranged on the sliding sleeve  5 . This enables a component to be omitted in the auto-injector. When the needle protecting tube  4  is advanced, the locking tongue  25  grips behind the end edge of the needle protecting tube  4 , such that the needle protecting tube  4  is secured against retracting relative to the active agent container  7  or the sliding sleeve  5 . When pressure is applied to the needle protecting tube  4  in the proximal direction, the needle protecting tube  4  shifted together with the sliding sleeve, the active agent container  7  and the injection needle  10 , relative to the casing “C”. 
         [0041]    In the foregoing description, embodiments of the present invention, including preferred embodiments, have been presented for the purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments were chosen and described to provide the best illustration of the principals of the invention and its practical application, and to enable one of ordinary skill in the art to use the invention in various embodiments and with various modifications as are suited to a particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth they are fairly, legally, and equitably entitled.