Abstract:
An injection syringe has a housing for a medicament ampule and a plunger movable longitudinally in the housing. A holder is connected to the syringe housing for detachably mounting an injection needle unit having a cannula support. The cannula support has a rearward end provided with a radial outer flange ring. A spreading sleeve is provided that is fastened with a cylinder ring on the syringe housing and has several elastic spreading tongues provided with forward ends remote from the cylinder ring and forming an annular cage. The spreading tongues have radial inner noses engaging the flange ring when the injection needle unit is inserted into the holder. An outer sliding sleeve surrounds the spreading sleeve and is movable against a spring force rearwardly. The front end of the sliding sleeve has an annular adjusting element that, upon rearward movement of the sliding sleeve, pushes the spreading tongues radially outwardly.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to an injection syringe as well as a disposal container for receiving injection needle units after their use on such injection syringe. 
   The injection syringe disclosed in EP 0 787 501 A2 is the starting point for the present invention; it comprises essentially the following elements:
         a housing for receiving a medicament ampule provided with a sealing member;   a plunger movable in the longitudinal direction of the housing for pushing the sealing member into the medicament ampule;   a holder for an injection needle unit, wherein the injection needle unit comprises a hub-shaped cannula support detachably insertable into the holder and having at its rearward end a radially outwardly oriented flange ring into which a cannula is inserted so as to project to the front and to the rear;   a spreading sleeve with elastic spreading tongues that have at their forward end radially inwardly oriented noses which, when the injection needle unit is inserted into the holder, engage behind the flange ring of the cannula support, as well as also radially oriented spreading projections and are mounted with their rearward ends on a cylinder ring fastened on the syringe housing; and   a sliding sleeve movable to the rear against the force of a spring, wherein the sliding sleeve is designed such that, when it is moved to the rear, it is pushed against the spreading projections so that in this way the spreading tongues are pushed radially outwardly for releasing the injection needle unit.       

   In this known injection syringe the spreading member has three spreading tongues provided at their rearward ends facing the cylinder ring with spreading projections that are radially inwardly oriented. The sliding sleeve is provided with radially outwardly oriented projections which upon movement of the sliding sleeve in the direction of the syringe housing press against the spreading projections provided on the spreading tongues so that the spreading tongues all together are moved outwardly and release in this way the injection needle unit. 
   The spreading projections provided at the rearward ends of the spreading tongues as well as the sliding sleeve provided with the outwardly oriented projections cause an increased expenditure that also makes manufacture more difficult, aside from the fact that only three spreading tongues cannot always ensure a safe insertion and fixation of the injection needle unit in the holding device. 
   SUMMARY OF THE INVENTION 
   The invention has the object to provide an injection syringe whose holder for the purpose of a simple manufacture is of a simpler configuration with respect to construction aspects than the known injection syringe, wherein additionally also a safe fixation of the injection needle unit in the holder is to be ensured. 
   As a solution to this object the injection syringe according to the invention is characterized in that the spreading member has at least four spreading tongues forming an annular cage and that the sliding sleeve at its forward end has an annular adjusting element with which the spreading tongues are pushed radially outwardly upon rearward movement of the sliding sleeve. 
   Overall, the sliding sleeve is a body having rotational symmetry which can be manufactured relatively simply in comparison to the sliding sleeve that is used in the known syringe and is provided with a number of outwardly oriented projections matching the number of spreading tongues. In the holder according to the invention, the projections or wider portions of the spreading tongues cooperating with the outwardly oriented projections of the sliding sleeve are not required. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in the following with the aid of the drawings: 
       FIG. 1  shows a side view of the injection syringe according to the invention with an injection needle unit inserted therein; 
       FIG. 2  shows an axial section of the holder for the injection needle unit that is configured according to the invention and is screwable onto the syringe housing, which holder comprises substantially a spreading sleeve, a tubular guide member for the injection needle unit, a needle ejector as well as an outer sliding sleeve; 
       FIG. 3  shows the spreading sleeve in an axial section; 
       FIG. 4  shows a side view of the guide member; 
       FIG. 5  shows a section view of the needle ejector; 
       FIG. 6  shows in a sectional view a portion of the cover of a disposal container; 
       FIG. 7  shows a partial plan view onto a cover according to  FIG. 6 . 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   The injection syringe A illustrated in  FIG. 1  has a housing  1  for receiving a medicament ampule that is of a conventional design and therefore not illustrated; it is closed at the rearward end by a sealing member and at its forward end by a septum. Into the forward end of the injection syringe A, the cannula attachment  3  of an injection needle unit B is detachably inserted by means of the holder  2  to be described in the following; the injection needle unit has a rearward cannula section that can be punched through the septum of the medicament ampule. A rod  5  that can be pushed by means of a handle  4  into the housing  1  supports at its leading end a plunger (not illustrated) which upon insertion of the rod  5  into the housing pushes the sealing member, closing off the rearward end of the ampule, into the ampule so that the medicament contained in the ampule can be injected by means of the outer cannula injection section  6  into a patient. 
   The injection syringe described by means of  FIG. 1  corresponds with respect to its basic configuration to the injection syringe described in EP 0 787 501. The syringe of the present invention differs from the known injection syringe essentially by the configuration of the holder  2  illustrated in  FIG. 2 . 
   The holder  2  is comprised in detail of the spreading sleeve  6 , illustrated as an individual part in  FIG. 3 , into which the cannula attachment  3 , indicated in dashed lines, is inserted; a tubular guide member  8  (see  FIG. 4 ) insertable from below into the spreading sleeve  7  and preferably inserted with press-fit; a needle ejector  9  illustrated in  FIG. 5  which is movable against the force of a spring  10  relative to the centering sleeve  7 ; as well as an outer sliding sleeve  11  that is movable relative to the spreading sleeve  7  screwed onto the housing  1  as will be described in the following. 
   The spreading sleeve  7  is comprised of a cylinder ring  12  having an inner thread; an inwardly oriented flange ring  12 . 1  adjoins the upper end of the cylinder ring. On this annular flange  12 . 1 , several, preferably eight, elastic spreading tongues  13  are provided that form an annular cage. On the forward free end of each spreading tongue  13 , a holding and guiding member  14  forming a radially inwardly projecting nose  14 . 1  is provided which has a guide surface  14 . 2  which extends at a slant inwardly from the top to the bottom. 
   The guide surfaces  14 . 2  of all spreading tongues  13  form a conical surface interrupted by the gaps a between neighboring spreading tongues  13 . 
   The guide member  8 , which is illustrated in  FIG. 4  and is inserted from below into the spreading sleeve  7 , for example, by press-fit, comprises a flange ring  15  resting against the underside of the flange ring  12 . 1 ; an adjusting and centering collar  16  resting against the inner edge of the flange ring  12 . 1 ; a central cylinder section  17  having a diameter which is reduced relative to the adjusting ring  16 ; as well as an upper cylinder section  18 . The guide member  8  is provided with a continuous central bore  19  into which a conical bore  20  opens at the upper end of the upper cylinder section  18 . 
   The central and upper cylinder sections  17  and  18  are provided, for example, with four recesses  17 . 1  and  18 . 1  that are radially inwardly oriented and extend in the axial direction; in the final mounted state of the holder  2 , they are positioned opposite the gaps a located between the spreading tongues  13  or aligned with them. 
   The needle ejector  9  is comprised of a ring  2 . 1  on which, for example, four radially inwardly oriented sheet-shaped ejector wings  2 . 2  are arranged which project past the upper side of the ring  21 . The arrangement of the ejector wings  2 . 2  is such that during axial movement of the needle ejector  9  they are guided in the recesses  17 . 1  and  18 . 1  through the gaps a between the cylinder tongues. 
   The sliding sleeve  11  has essentially the shape of a cylinder bushing having at the upper end an inwardly oriented flange ring  11 . 1  against whose underside the upper rim of the ring  21  of the needle ejector  9  is pushed by the spring  10 . A conical ring  11 . 2 , which is oriented at a slant inwardly and to the rear and has of tongue-shaped cross-section, adjoins the flange ring  11 . 1 . The lower edge of the conical ring projects into the conical surface formed by the guide surfaces  14 . 2  of the spreading tongues  13 . 
   The threaded bushing  12  of the spreading sleeve  7  is provided at its outer periphery with an axial groove  12 . 2 ; a groove section  12 . 3  extending in the circumferential direction of the threaded bushing adjoins an upper end of the axial groove. The sliding sleeve  11  is provided with a radially oriented threaded bore  23  for receiving a stud screw  24  which has a projection  24 . 1  projecting into the groove  12 . 2  or  12 . 3 . When the projection  24 . 1  projects into the circumferential groove  12 . 3 , the sliding sleeve  11  is secured against axial movement. This state corresponds to the state of use of the injection syringe A with the injection needle unit B inserted into the holder  2 . This state is indicated by the markings  1 . 1  and  11 . 3 , aligned with one another, on the outer circumference of the sliding sleeve  11  and on the outer circumference of the syringe housing  1 , respectively. In  FIG. 1  the markings  1 . 1  and  11 . 3  indicate the state in which the projection  24 . 1  of the stud screw  24  is positioned at the end of the circumferential groove  12 . 3  so that the sliding sleeve  11  is secured against axial movement. 
   For insertion of an injection needle unit into the holder  2 , first the rearward cannula section, not illustrated, is inserted through the conical bore  20  into the central bore  19  until the radially outwardly oriented flange ring  3 . 2  of the cannula support  3 . 1  rests against the guide surfaces  14 . 2  of the spreading tongues  13 . By further inward pushing of the cannula support  3 . 1  into the holder  2 , the flange ring  3 . 2  of the cannula support  3 . 1  moves along the guide surfaces  14 . 2  so that the spreading tongues  13  are pushed outwardly until the flange ring  3 . 2  has past the holding and guiding member  14  so that the spreading tongues  13  can return elastically into their initial position and the flange ring  3 . 2  assumes a position underneath the noses  14 . 1  as illustrated in  FIG. 3 . 
   The underside of the flange ring  3 . 2  in this state is supported on the ring shoulder surrounding the upper cylinder section  1 . 8  of the guide member  8 ; the ring shoulder is formed by the free upper side of the central cylinder section  1 . 7 . 
   The injection needle unit  3  is thus secured against axial movement in both directions as long as the sliding sleeve  11  is in the position illustrated in  FIG. 1 . 
   For removing or ejecting the injection needle unit  3  after its use, the sliding sleeve  11  is rotated relative to the housing  1  in the direction of the marking  1 . 1  provided on the housing  1  so that the projection  23  of the stud screw  24  is adjustable along the circumferential groove  12 . 3  in the direction toward the axial groove  12 . 2 . As soon as the stud screw projection  23  reaches the area of the axial groove  12 . 2  and the system is thus “unlocked”, the sliding sleeve  11  can be moved to the rear counter to the spring force of the restoring spring  10  positioned between the needle ejector  9  and the annular flange  12 . 1  of the spreading sleeve  7 . This causes the conical ring  11 . 2 , arranged at the forward end of the sliding sleeve  7  at a slant inwardly and to the rear, to be pushed against the guide surfaces  14 . 2  provided on the spreading tongues  13  and extending at a slant inwardly; in this way, upon further movement of the sliding sleeve  11  to the rear the spreading tongues  13  are pushed outwardly. Accordingly, the flange ring  3 . 2  provided on the cannula support  3 . 1  will be released by the securing and guiding members  14  or their noses  14 . 1  so that the cannula attachment  3 . 1  and thus the entire injection needle unit  3  can be ejected from the holder  2  under the effect of the restoring spring  10  acting on the needle ejector  9 . 
   This ejection is realized preferably into a disposal container whose cover  50  illustrated in  FIGS. 6 and 7  has a circular opening adjoined by a downwardly conically tapering pipe section  52  having at its lower edge an inwardly oriented ring flange  53 . On the inner wall of the pipe section  52  at least one holding element  54  is provided which is capable of securing the sliding sleeve  11  against rotation relative to the disposal container and thus also relative to the injection syringe when the sliding sleeve  11  of an injection syringe is inserted from above into this pipe section  52 . 
   According to  FIG. 7 , on the inner wall of the pipe section  52  preferably eight holding elements in the form of clamping stays  54  extending along the surface lines of the pipe section  52  are provided. 
   The forward end of the sliding sleeve  11  has a section conically tapering in the direction toward the forward sliding sleeve; at its side at least one rib  11 . 3  insertable between the clamping stays  54  is provided. 
   For a contact-free ejection of the used injection needle unit  3  the injection syringe with its sliding sleeve  11  is inserted into the pipe section  52  of the disposal container, not illustrated otherwise, so that the sliding sleeve  11  is secured within the pipe section  52  against rotation. 
   By rotating the housing  1  the system is “unlocked” in the way described above so that the injection syringe with its spreading sleeve  7  is moved in the direction of the disposal container so that the spreading tongues  13  are pushed in the above described way by the conical ring  11 . 2  outwardly and, in this way, release the injection needle unit  3  or its cannula attachment  3 . 1 .