Abstract:
A sealing device for a container comprising a circular cap designed to seal the neck of the container and a cover made from a synthetic material capable of covering both the neck and the cap fitted on the neck, the cover being provided with means for locking onto the neck, the cover being in one piece and comprising a skirt capable of radially surrounding a collar of the neck of the container, and an annular portion provided with a central opening allowing permanent access to the cap, and the skirt having at least two jamming areas for jamming the cap and, on the inner radial face thereof between the two jamming areas, a release area with a diameter strictly greater than the minimum unstressed diameter of the cap.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a sealing device for a container, said device comprising a circular stopper designed to seal the neck of the container, as well as a cap. The invention also relates to a container, for example a drug cartridge, equipped with such a sealing device. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is known to store certain drugs injectable by parental administration in liquid form in a container made from glass named “cartridge” having a diameter of 7 mm and sealed by a sealing washer. The drugs thus stored are ready to be used in syringes, for example, for dental care, or in injector pens. 
         [0003]    Once filled with a drug, a cartridge is normally sealed by a sealing washer covered by a capsule made from aluminium. Said principle of sealing is widely used because it guarantees a good stability of the active principle of the drug, as well as the integrity of the drug to be conserved. With the current systems, the sealing washer is pre-installed inside the capsule made from aluminium, then same is crimped on the neck of the cartridge by means of a knurling tool. Such a method of crimping capsules made from aluminium is likely to generate debris from aluminium, glass or paint applied on the capsule made from aluminium, which makes said method incompatible with a use in a cleanroom of class ISO 5 according to the standard ISO 146 44. Moreover, there remains a risk of rotation of the sealing washer in relation to the cartridge, to the extent that the sealing washer does not fulfil the function thereof of isolation of the interior volume of the cartridge in relation to the exterior, hence a risk of deterioration of the active principle of the drug. Finally, the particles of aluminium, glass or paint released during the crimping are likely to pollute the upper surface of the sealing washer which is accessible via the capsule. During the perforation of the sealing washer for sampling the contents of the cartridge, said particles deposited on the surface of the sealing washer risk contaminating the product contained in the cartridge and, consequently, the patient. This is all the more significant as certain drugs packaged in cartridges are used for long-term treatments by means of injector pens, for example, insulin injector pens. 
         [0004]    It is known from WO-A-94/04424 to use a cap made from multi-piece plastic material that is intended to be immobilised around the stopper of the sealing device. Said relatively complex structure is both expensive to manufacture and bulky, such that same is not adapted to the sealing of a container of small cross-sectional dimensions, such as a cartridge. Moreover, if the dimensions of the device known from WO-A-94/04424 were reduced in view of the use thereof on a container of small cross-sectional dimensions, such as a cartridge, the compressive force necessary for securing the stopper on the neck of the container would result in a radial expansion of said stopper likely to tear the cap. 
       SUMMARY 
       [0005]    The invention more specifically intends to overcome said drawbacks by proposing a new sealing device particularly suitable for a cartridge and which enables an effective isolation of the contents of the container, without risk of loss of the physical integrity thereof. 
         [0006]    To this effect, the invention relates to a sealing device for a container, said sealing device comprising a circular stopper designed to seal the neck of the container and a cap made from synthetic material capable of covering both the neck and the stopper fitted on said neck, said cap being provided with means for locking onto the neck. In accordance with the invention,
       the cap is in one piece and comprises a skirt, capable of radially surrounding a collar of the neck of the container, as well as an annular portion provided with a central opening allowing permanent access to the stopper,   the skirt has at least two jamming areas for jamming the stopper and   the skirt has, on the inner radial surface thereof and between the two jamming areas for jamming the stopper, a release area with a diameter strictly greater than the minimum unstressed diameter of the stopper.       
 
         [0010]    Thanks to the invention, the one-piece structure of the cap made from synthetic material enables same to effectively provide a function of isolation of the stopper, whilst being of an attractive cost. The installation thereof on the neck of the container is not likely to release particles of metal or paint. The jamming areas for jamming the stopper make it possible to temporarily hold the stopper inside the cap, before installation of the cap on the container. The release areas make it possible to accommodate a radial expansion of the stopper when exposed to an axial compressive force which firmly secures the stopper against the surface of the neck opposite the bottom of the vial. Thus, the cap is not likely to break or tear when exposed to a centrifugal force exerted by the stopper due to the radial expansion thereof. 
         [0011]    According to advantageous but not mandatory aspects of the invention, such a sealing device may incorporate one or more of the following features, taken in all admissible technical combinations:
       The stopper is a washer made from elastomer.   The outside diameter of the skirt is less than 8.5 mm, preferably less than 8.25 mm, more preferably equal to 8.1 mm.   In each release area, the skirt has a radial thickness less than 0.35 mm, preferably equal to 0.3 mm.   The skirt has three jamming areas for jamming the stopper evenly distributed about a central axis of the skirt, as well as a release area between each pair of adjacent jamming areas.   The locking means comprise teeth each having a surface practically perpendicular to a central axis of the skirt, whereas each release area is aligned, in a direction parallel to the central axis, with a locking tooth.   The skirt has three release areas and each release area extends, in relation to the central axis of the skirt, over an angular sector with an angle at the apex having a value between 65° and 75°.   Each locking tooth extends, in relation to the central axis of the skirt, over an angular sector with an angle at the apex having a value less than that of the angle at the apex of the angular sector of a release area.       
 
         [0019]    The invention also relates to a container, in particular a drug cartridge, equipped with a sealing device as mentioned above. Such a container can be manufactured in a more reliable manner than those of the prior art, with a particularly attractive cost. 
         [0020]    Advantageously, said container has an outside diameter between 8.55 and 12 mm and the skirt of the sealing device has an outside diameter strictly smaller than the outside diameter of the container, preferably equal to 8.1 mm. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The invention will be better understood and other advantages thereof will appear more clearly in light of the following description of one embodiment of a sealing device and of a container according to the principle thereof, given only as an example and made in reference to the appended drawings, wherein: 
           [0022]      FIG. 1  is a perspective view of a drug storage cartridge equipped with a sealing device according to the invention, 
           [0023]      FIG. 2  is a partial cross-section on a larger scale along the plane II in  FIG. 1 , 
           [0024]      FIG. 3  is an exploded view in perspective and on a smaller scale of the portion of the cartridge and of the sealing device shown in  FIG. 2 , 
           [0025]      FIG. 4  is an exploded perspective view, with partial cut away, of the portions shown in  FIGS. 2 and 3 , 
           [0026]      FIG. 5  is perspective view on a larger scale of a cap shown in  FIGS. 1 to 4 , 
           [0027]      FIG. 6  is a cross-section in perspective along the plane VI in  FIG. 5 , 
           [0028]      FIG. 7  is a cross-section along the plane VII in  FIG. 5 , 
           [0029]      FIG. 8  is a cross-section along the line VIII-VIII in  FIG. 7 , the plane of the cross-section in  FIG. 7  has been shown here as VII -VII, 
           [0030]      FIG. 9  is a cross-section along the line IX-IX in  FIG. 8 , 
           [0031]      FIG. 10  is a cross-section in perspective when the stopper of the sealing device is pre-mounted in the cap, before installation on the neck of the cartridge, 
           [0032]      FIG. 11  is a cross-section equivalent to  FIG. 7  in the configuration of  FIG. 10 , 
           [0033]      FIG. 12  is a cross-section along the line IX-IX in  FIG. 11  and 
           [0034]      FIG. 13  is a cross-section along the line VIII-VIII in  FIG. 2 , on the same scale as  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    The container  1  made from glass shown in the figures is a cartridge, that is to say an elongated-shaped vial centred on a longitudinal axis X1 and having a circular section cylindrical body  11  the outside diameter D1 of which is between 8.55 and 12 mm. Alternatively, the cartridge  1  can be made from plastic material. Said cartridge is provided with a neck  12  defining a mouth  13  through which it is possible to fill the cartridge  1  and which is surrounded by a collar  14  on which  141  denotes an annular surface surrounding the opening of the mouth  13  and  142  denotes an annular surface oriented opposite the surface  141  and rotated towards the body  11  and towards the bottom  15  of said body. 
         [0036]    The bottom  15  may consist of a piston moveable along the axis X1 inside the body  11 . 
         [0037]    A sealing device  20  is mounted on the neck  12  and comprises a stopper  21  formed by a washer made from elastomer which is circular and centred on an axis X21. The outer peripheral surface  211  of the stopper  21  is frustoconical and converging in the direction of a disc-shaped surface  212 , opposite another surface  213  also disc-shaped. Considering the normal configuration of storage of the cartridge  1 , in which same rests with the bottom  15  thereof on a flat and horizontal surface, the surface  212  is referred to as upper surface, whereas the surface  213  is referred to as lower surface. 
         [0038]    The sealing device  20  also comprises a cap  22  made by moulding of plastic material, for example, polyoxymethylene. 
         [0039]    Said cap is in one piece and comprises a skirt  221  centred on a central axis X22 of the cap  22  and the outer peripheral surface  222  of which is cylindrical and with a circular section centred on the axis X22. The cap  22  also comprises an annular portion  231  which extends from the skirt  221  and in the direction of the axis X22. Said annular portion is connected to the skirt  221  by three branches  241  evenly distributed, at 120° from one another, about the axis X22. The annular portion  231  defines an opening  232  centred on the axis X22 which allows permanent access to the surface  212  of the stopper  21 , when said stopper is inserted inside the cap. 
         [0040]    Along the skirt  221 , between two adjacent branches  241 , the cap  22  is provided with three circular arc-shaped openings  251  and which each extend along an angular sector the angle at the apex of which is noted α. In practice, said angle a has a value between 65° and 75°, preferably around 70°. 
         [0041]    Furthermore, the cap  22  is provided with three teeth  261  evenly distributed about the axis X22 and designed for locking the cap  22  in place on the neck  12 . Each tooth  261  comprises a surface  262  which is practically perpendicular to the axis X22 as well as a surface  263  which is frustoconical and diverging opposite the portion  231 , that is to say in the direction of the edge  223  of the skirt  221  opposite the openings  251 . In reference to the figures, said edge is referred to as lower edge, whereas the portion  231  is considered as arranged at the level of the upper edge  224  of the skirt  221 . 
         [0042]    The surface  262  is practically perpendicular to the axis X22 in this sense that a straight line aligned on said surface, in a plane radial to the axis X22, forms with said axis an angle superior to 70°, preferably to 75°. Said orientation of the surface  262  provides effective anchoring of each tooth  261  under the collar  14 , against the surface  142 . 
         [0043]    In mounted configuration of the cap  22  on the neck  12 , the surface  262  of each tooth  261  is facing and opposite the surface  142 . 
         [0044]    The maximum unstressed diameter of the stopper  21  is noted D21 max , that is to say in practice the diameter of the lower surface  213 , before installation of the stopper  21  in the cap  22 . The minimum unstressed diameter of the stopper  21  is noted D21 min , that is to say in practice the diameter of the surface  212 , before installation of the stopper  21  in the cap  22 . 
         [0045]    The skirt  221  is provided with three areas  225  evenly distributed about an axis X22 and in each one of which the inner radial surface  226  of the skirt  221  has a radius R225 equal to or slightly smaller than half of the diameter D21 max . Thus, the three areas  225  make it possible to retain, by radial jamming and/or friction, the stopper  21  inside the cap  22  when same is inserted inside the cap in the direction of the arrow F1 in  FIG. 4 . 
         [0046]    The skirt  221  is provided, on the inner surface  226  thereof, with a peripheral bead  228  which connects the teeth  261  and which makes it possible to hold the cap  22  in position in the mould thereof, during the unmoulding thereof. 
         [0047]    Furthermore, the portion  231  is provided with a circular rib  233  arranged on the inner surface  234  thereof, on the inner volume side of the cap  221  and which is intended for superficially penetrating the surface  212  of the stopper  21 , when the sealing device  20  is fitted in the cartridge  1 . 
         [0048]    The inner radial surface  226  of the skirt  221  does not have a constant radius about the axis X22 but comprises three areas  227  in which the radius of the surface  226  has a value R227 greater than that of the radius R225. In practice, the radius R227 is strictly greater than half of the diameter D21 min , more specifically greater by 0.15 mm more than half of said radius. In other words, the diameter D227 of the surface  226 , which is equal to the double of the radius R227, is strictly greater than the diameter D21 mm , by 0.3 mm. 
         [0049]    Thus, when the stopper  21  is placed in the capsule  22  in pre-mounted configuration shown in  FIGS. 10 to 12 , a free space E is arranged between the outer external surface  211  of the stopper  21  and the inner radial surface  226  of the skirt  221  at the level of the release areas  227 . Said free space does not affect the holding in position of the stopper  21  in the cap  22  since said holding in position is provided by the interaction of the stopper  21  with the jamming areas  225 . 
         [0050]    Moreover, each tooth  261  is extended in the direction of the edge  224  of the skirt  221  by a back  264  which defines, opposite the surface  262 , a shoulder  265  perpendicular to the axis X22 and oriented towards the edge  224 . The inside radius R264 of a back  264  is smaller than or equal to the radius R225, such that the shoulder  265  constitutes a stop to possible movement of the stopper  211  in the direction of the lower edge  223  of the skirt  221 . 
         [0051]    Each tooth  261  extends, in relation to the axis X20 along an angular sector the angle at the apex of which is noted β. This angle has a value between 45° and 55°, said value being less than the value of the angle α. 
         [0052]    The teeth  261  are placed, in relation to the axis X22, in angular sectors incorporated into the angular sectors of the openings  251 . In other words, the teeth  261  and the openings  251  are aligned two by two in directions Δ22 parallel with the axis X22. This makes it possible to produce the openings  221  and release areas  227  by means of a sliding block for forming the surfaces  262  and  265  of the teeth  261  and of the backs  264  during the moulding of the cap  22 , in a single operation. The values of the angles a and [3 make said moulding possible in one operation. 
         [0053]    When the sealing device  20  is fitted on the cartridge  1 , as shown in  FIGS. 1 ,  2  and  13 , the stopper  21  is compressed between the surface  234  of the portion  231  and the surface  141  of the collar  14 . The rib  233  superficially penetrates the stopper  21 . When exposed to the axial compression, the stopper  21  tends to expand radially in relation to the axes X1 and X22 which are then combined. This is possible by filling the spaces E previously existing at the level of the release areas  227 . In other words, the release areas  227  make it possible to accommodate the radial expansion of the stopper  21  when exposed to the axial force that same experiences in order to effectively seal the mouth  13 , without risk of tearing the skirt  221 . Thus, as shown by comparing  FIGS. 12 and 13 , when the stopper  21  is axially compressed, same can expand radially opposite the areas  227 , by filling the spaces E, without risk of tearing or plastically deforming the skirt  221 . 
         [0054]    The invention is shown in the figures in the case where the diameter D21 max  of the stopper  21 , which is measured without stress on said stopper, is strictly smaller than the double of the radius R227. In practice, given the taper of the surface  211 , it is possible that said maximum diameter D21 max  is equal to, or even slightly greater than, the double of the radius R227, so long as the minimum diameter D21 min  of the stopper  21  at the level of the upper surface  212  of the stopper  21  remains strictly smaller than the double of the radius R227. Indeed, in this case, the spaces E do not extend over the entire height of the stopper  21  but over the portion of same the unstressed diameter of which is strictly the double of the radius R227. In this case, the radial expansion of the stopper  21  when exposed to the compressive force only takes place in the vicinity of the upper surface  212  thereof. 
         [0055]    According to another variation, the surface  211  of the stopper  21  can be cylindrical. In this case, the diameters D21 min  and D21 max  are identical and equal to a nominal diameter of the stopper. The radius R225 is then smaller than half of said nominal diameter, whereas the diameter D227 is strictly greater than said nominal diameter. 
         [0056]    As the skirt  221  is fairly unstressed by the radial expansion of the stopper  21 , the radial thickness thereof can be small. In particular, said radial thickness can have a value e227 at the level of the release areas  227  less than 0.35 mm, preferably equal to 0.3 mm. At the level of the areas  225 , the radial thickness e225 of the skirt  221  has a value strictly greater than the value e227, in practice greater than 0.4 mm, preferably equal to 0.45 mm. 
         [0057]    Given the small radial thickness of the skirt  221 , the outside diameter D22 of the cap  22 , that is to say that the diameter of the surface  222 , can be strictly smaller than the diameter D1, for example, equal to 8.1 mm. Thus, the sealing device  20  does not radially protrude in relation to the body  11  of the cartridge, which is compatible with the use of the cartridge in an injector pen or any other equivalent device. 
         [0058]    Alternatively, the number of areas  225  and  227  of openings  251  and of teeth  261  can be different by three. The number of areas  225  is greater than two in order to enable effective jamming of the stopper  21  in pre-mounted configuration. 
         [0059]    The features of the embodiments and variations envisaged above can be combined together.