Patent Publication Number: US-6986444-B2

Title: Dispenser for discharging a fluid medium

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a dispenser for discharging a fluid and preferably liquid, especially a pharmaceutical substance-containing medium. 
   In the case of such dispensers the medium is stored in a medium container. A delivery device, e.g. in the form of a plunger pump, is used for discharging the medium. The delivery device delivers the medium from the medium container to a discharge location, generally a discharge nozzle. 
   Such a dispenser is e.g. described in EP 571 280 B1. 
   In the case of such dispensers there must be a fluid-tight fastening of the medium container to the delivery device, so that the medium can only pass out of the medium container via the fluid path of the delivery device. For this purpose on both the medium reservoir and on the delivery device fastening portions are provided used for fastening the two parts to one another. 
   Such fastening devices generally suffer from the disadvantage of taking up a large amount of space. Usually a relatively large bottle neck is provided on medium containers. In the vicinity of the bottle neck a corresponding material convexity is required, so that it is possible through crimp rings or the like to fasten the delivery device to the medium containers. The construction of screw threads, such as are in part standard, is also very space-consuming. It is also possible to have a locking or snapping fastening of the delivery device to the medium container, e.g. by means of a type of intermediate ring or insert, as known from EP 571 280 B1, but this leads to a long construction. However, particularly with small volume medium containers, the design task is to produce the dispenser with a small number of easily manufacturable components, which must also be easily fitted and leading to a short construction. 
   OBJECT OF THE INVENTION 
   Thus, the object of the invention is to provide a fluid-tight, non-releasable or only under great force releasable connection between the dispenser delivery device and the dispenser medium reservoir. 
   SUMMARY OF THE INVENTION 
   In the case of a dispenser for discharging a fluid, preferably liquid medium and which more especially can contain a pharmaceutical substance, at least two parts are provided. Firstly there is a medium container for storing the medium and secondly a delivery device fastenable to the medium container. The delivery device is used for delivering medium, e.g. a dosed medium quantity, from the medium container to a discharge nozzle. For fastening together the medium reservoir and the delivery device fastening surfaces are formed on both parts. 
   According to the invention in the fastening area there is a gap between the medium container and the delivery device. A mostly elastically, but also somewhat plastically deformable ring fastener, whose wall thickness prior to installation is larger than the gap is used. This plastically deformable ring fastener is fitted to one of the two parts, i.e. medium container and delivery device, before they are fastened together. The ring fastener oversize is e.g. about 0.355 mm. 
   The ring fastener may comprise two areas. In the first area the ring fastener is constructed as a continuous annulus, i.e. with an uninterrupted circumferential sealing surface, whereas in the second area there is at least one slit in the ring. Therefore it is easier to be inserted under pressure in the bottle neck of the container without impairing the holding force. The slit allows to store the displaced oversize material and creates a reservoir of elasticity. The slit may preferably be substantially axially oriented, though a deviation therefrom of about 10° were found to be uncitical. The slit preferably has a width approximately corresponding to the wall thickness of the ring fastener, e.g. between half and double of the wall thickness. Particular advantage arises with constructions where the ratio of the length of the first area to that of the second area, in each case in the axial direction, is approximately 1 to 5 to 1 to 10. 
   In a further embodiment of the invention, the ring fastener is made from a plastics material, particularly manufactured by injection molding. The Shore hardness of the material used for the manufacture of the ring fastener is preferably approximately 50 Shore A. In a further development of the invention the ring fastener is directly and integrally applied to the fastening portion of the part on which it is constructed, i. e. the outer wall of the delivery device, which may be the pump cylinder. This is done by shaping softer plastic material on the delivery device during injection molding by a two-component injection molding process. Preference is given to variants of the invention in which the ring fastener is injection molded in the fastening portion of the delivery device. Thus, the fastening portion of the medium container is preferably constructed as a smooth-walled, short bottle neck. 
   According to developments of the invention the fastening portion of the delivery device is constructed as a cylindrical sleeve. The cylindrical sleeve is preferably enveloped by the fastening portion of the medium container. 
   It is also advantageous if at least one of the sides of the ring fastener facing the fastening portions is at least zonally scaled, particularly microscaled. Such a microscaling prevents a relative movement in the release direction of the connection between medium container and delivery device. This measure more particularly produces a particularly strong, difficultly releasable connection through the ring fastener. 
   The scaling permits a relatively easy fastening together of the two parts, but not a release thereof, because the scales permit a movement in the scaling direction, but block an opposing movement. The scales, which can be formed during injection molding, are for this purpose constructed in such a way that their low side is at the front in the insertion direction and the raised side is at the rear in the insertion direction. Such a microscaling is obtained more particularly by adding a scaling-forming material to that of the ring fastener during manufacture, e.g. by injection molding. The term microscaling is used if the raising of the scaling with respect to a planar outer contour is below 1 mm. 
   Additionally or alternatively to the formation of a scaling, it is possible to provide the plastics material forming the ring fastener with additives. These are in particular elasticity additives, preferably those which simultaneously produce a slid-preventing effect on the surface. Such additives can often also produce a soft touch or soft grip effect. The elasticity of the plastics material used is increased. Plastics usable for producing the ring fastener are e.g. polyethylene (PE), polypropylene (PP), etc. The elasticity-increasing effect of the additives is required during the pressing in of the ring fastener. As a result of the fact that the external diameter of the ring fastener may be larger than the container opening, a blocking action occurs. The high elasticity of the plastics material ensures that it is not possible to turn the plastics material with respect to the container and bring about a sliding movement. Instead there is a good adhesion of the ring fastener to the medium container surface in the vicinity of its bottle neck. 
   According to the invention it is advantageous if the connection between the medium container and the delivery device produced by means of the ring fastener has a fluid-tight construction. The latter also requires a careful choice of the material used for the ring fastener, because said material must be stable and dissolving-proof with respect to the medium stored in the medium container and its ingredients. In order to facilitate the introduceability of one part to be fastened with respect to the other, it can be advantageous if the material thickness of the ring fastener increases axially and in particular is wedge-shaped in cross-section. In a particularly simple manner, in the case of the ring fastener according to the invention the two parts can be interconnected by pressing. 

   
     The invention is described in greater detail hereinafter relative to an embodiment shown in the attached drawings, wherein represent: 
       FIG. 1  In a diagrammatic, part-sectional view a delivery device joined to a medium container by pressing. 
       FIG. 2  A delivery device with a ring fastener layer injection molded onto said device in a diagrammatic, part sectional view. 
       FIG. 3  A more detailed side view of the ring fastener with scaling. 
       FIG. 4  A partial sectional side view of a dispenser using the fastener layer shown in FIG.  2  and  3   
   

     FIG. 1  shows in part sectional form the medium container  21  and delivery device  22  of a dispenser  20 . The delivery device can e.g. be a plunger pump or some other pump means, which sucks by means of a suction pipe  30  medium stored in the medium container  21  and delivers it to the discharge opening  31 , e.g. as a spray, on operating the delivery device  22 . The discharge opening  31  can e.g. be an issuing opening, which issues into the nozzle, e.g. a spraying nozzle of a discharge mechanism or dispenser. 
   In  FIG. 1  both the medium container  21  and the ring fastener  26  are shown in sectional form, whereas the delivery device  22  is shown in non-sectional form. 
   The medium container has a fastening portion  23 , which is substantially cylindrical with a central axis  40  and which is a bottle neck. Opposite to the fastening portion  23  when, as shown, the delivery device  22  is in its ready-to-operate position fastened to the medium container  21 , is located the fastening portion  24  of the delivery device  22 . The fastening portions of the two parts have fastening surfaces facing each other which are extending in a mostly cylindrical shape around the central axis, not withstanding small deviations therefrom, e.g. because of draft angles. In order to produce the gap  25  between the inner edge of the fastening portion  23  of the medium container  21  and the fastening portion  24  of the delivery device  22 , the corresponding diameters differ from one another by said gap dimension  25 . Account can be taken of manufacturing tolerances in the vicinity of the two fastening portions  23 ,  24 , where the resulting gap dimension is filled by the material of the ring fastener  26 . Thus, the material of the ring fastener  26  creates a fluid-tight connection between the medium container  21  and the delivery device  22 . Thus, apart form the fluid path in the delivery device  22 , the medium container  21  is sealed in fluid-tight manner for the medium enclosed therein. The media stored in the medium container  21  can be cosmetics, such as perfumes, fragrances, etc., as well as media incorporating at least one pharmaceutically active substance. The pharmaceutical substances can in particular be Freund&#39;s adjuvants, opiates and pharmaceutical substances in general which are administerable in dosed form and which are in particular administered to body cavities, such as the mouth or nostrils. 
   The plastics material from which the ring fastener is made, is a soft, elastic and somewhat flowable material. It is chosen in such a way that as a result of elastic deformation on pressing together with the delivery device  22  into the medium container  21  it is displaced from the gap and extends into the container. In addition, it is also possible to make slits  29  in the ring fastener  26 . The slits  29  do not extend over the entire axial length of the ring fastener  26 . They are in fact limited to a specific partial length, which in the medium container in question is in the lower zone thereof and away from its opening. The top zone of the ring fastener is in the form of a closed ring in order to ensure fluid tightness. The substantially axially oriented slits  29  in the ring fastener  26  serve to receive the material of the ring fastener  26  displaced as a result of the smaller gap dimension  25 . It creates thereby a reservoir of elasticity. However, it is also possible for a pressure compensating opening  32  of the delivery device  22  to issue in the vicinity of one of the slits  29 . By means of the pressure compensating opening  32  the interior of the medium container  21  is connected via the delivery device to the atmosphere to enable discharge of the medium stored therein without forming a vacuum in the container  21 . If the slit  29  is given an adequate width, elastically displaced material of the ring fastener  26  does not completely close the slit  29  and consequently there is always a fluid connection between the pressure compensating opening  32  and the interior of the medium container  21 . As a function of the elasticity and flow behaviour of the material from which the ring fastener  26  is made, a gap width must be determined for this purpose. The gap width is approximately of a value corresponding to the material thickness, i.e. the radial diameter of the ring fastener  26 . 
   As has already been stated, the wall thickness of the ring fastener  26  in its original state, i.e. when the delivery device  22  is not yet connected to the medium container  21 , is larger than the gap dimension  25 . If the medium container  21  is closed by pressing with the delivery device  22 , as a result of the smaller gap  25  the ring fastener  26  is elastically deformed to create and maintain a considerable pressure between the fastening surfaces of the fastening portions sufficient to tightly hold the delivery device in the container opening. As a result of the deformation the relatively soft material of the ring fastener  26  is made to flow. The relatively soft material can be a plastics material, particularly one which is moldable by injection molding. The Shore hardness of the material of the ring fastener  26  is in a range between approximately 30 and 60 Shore A and is preferably approximately 50 Shore A. If the plastics material is PE or PP, said value for the material is correspondingly adjusted by adding plasticizers. It is particularly important for the material that during pressing it flows, so that the ring fastener  26  enters the gap resulting from the gap dimension  25  and fills the same. As a result of the flow process a certain amount of material can pass out of the gap towards the interior of the medium container. However, the material of the ring fastener  26 , as a result of its composition, must not be applied in waves, sheared or otherwise deformed. It can also arise that a slight bead is formed by the material of the ring fastener  26  and is located at the lower edge of the fastening portion  23  of the medium container  21 . 
   It must be borne in mind that as a rule, due to the manufacture, with bottle necks to be very precisely produced, following the upper edge there is a small, undesired, but scarcely avoidable internal diameter increase. Also in the area of this increase there must be a firm engagement of the material of the ring fastener  26  both on the delivery device and on the medium container  21 , so as to ensure a reliable, fluid-tight connection between the two parts, which is attainable by a viscous flow behaviour of the ring fastener material. 
     FIG. 2  shows a discharge device  22  with a integral ring fastener  26  constructed by injection molding, particularly two-component injection molding. The ring fastener  26  comprises a first area  27  in the form of a closed ring and an area  28  in which there is at least one slit  29 , which is substantially axially directed. The width of the slit  29  approximately corresponds to the material thickness. In delivery devices and dispensers in which the invention can be used, the ring fasteners  26  have an approximate length of 10 mm. The material thickness, i.e. the difference between the internal and external diameters of the ring forming the ring fastener  26 , is approximately 1 to 1.5 mm. The gap dimension  25  between the internal diameter of the medium container  21  in the fastening portion  23  and the external diameter of the delivery device  22  in its fastening is approximately 0.5 mm. By means of the material thickness of 1 to 1.5 mm of the ring fastener  26 , it is consequently possible to compensate clearances and tolerances in the pump casing and medium container. 
   To permit a very easy insertion of the ring fastener  26  and delivery device  22  into the opening and the fastening portion  23  of the medium container  21 , the ring fastener  26  can be inclined and in particular have a wedge-shaped construction, the hypotenuse of the wedge being shaped on the outer side facing the medium container  22 . The wedge shape in particular only extends within the slotted, second area  28 . The ratio of the length of the slotted area  28  to the closed, ring-shaped, first area  27  of the ring fastener  26  is approximately 5 to 10 to 10 to 1. In the unslotted, upper area  27 , the ring-shaped body has its full wall thickness over the entire length and with said portion serves to provide the fluid-tight connection between the medium container  21  and the delivery device  22 . 
   It is advantageous to provide a scaling on the outside of the ring fastener  26  facing the medium container  21  in order to ensure an easy connection by pressing together of the two parts the medium container  21  and the delivery device  22  with the ring fastener  26  molded thereon, but at the same time to make an release of the connection as difficult as possible. The scaling is barbed and formed in such a way that the scales point in the direction opposite to the extraction or removal of the delivery device  22  from the medium container  21 . 
     FIG. 3  shows on a larger scale a side view of a delivery device  22  with a ring fastener  26  molded onto the outside of the delivery device  22 . The ring fastener  26  comprises an annular, closed, first area  27 , where the ring fastener material is constructed in continuous form and a second, slotted area  28 . Slits  29  are made at regular intervals within the slotted area  28 . It is possible to have only a single slit on the circumference of the ring fastener  26 . However, preferably there are several slits  29  arranged with a regular angular, mutual spacing. There can in particular be three to five slits. In the regions between the slits  29  of the second area  28  are formed scaling areas  34 , which in each case comprise a plurality of microscales  33 . The scales are constructed in such a way that at the end thereof facing the first area  27  they project by approximately 3/100 mm over the outer contour of the second fastening portion  24 . The consequently oppose an extraction of the delivery device  22  from the medium container  21 . The scales e.g. have a length of 1 mm and are arranged in juxtaposed, axially directed rows, adjacent rows being mutually displaceable by half a scale length. In the region between the slits  29  of the second area  28  of the ring fastener  26 , can in each case be provided scaled areas  34 , which form the preponderant part of the surface of the second area. The scaling on the surface of the ring fastener  26  is produced during the Molding process for said fastener, the shaping being obtained through the shape of the injection mold. 
   In order to ensure a very good adhesion and a limited slip tendency during movements between the ring fastener  26  and the medium container  21 , it is possible to provide a very soft or so-called soft touch characteristic for the material of the ring fastener  26 . The soft touch characteristic is generally obtained by adding a corresponding quantity of plasticizers and foaming agents in the region of the plastics material for the ring fastener  26 . The concentration and dosage of the plasticizer are in particular dependent on the choice of the plastics material and that of the plasticizer. It may be necessary to establish by tests which plasticizer concentration should be present in the plastics material. 
   Two-component injection molding, in which in two directly succeeding working steps the two parts are produced by injection molding and more particularly in the same mold, is a preferred process for the formation of a ring fastener  26  on a delivery device  22 . The delivery device  22  is made from a first, dimensionally stable plastics material, whereas the ring fastener  26  is usually also made from a plastics material, but which is plastically deformable and for this purpose has a Shore hardness of approximately 50 Shore A, i.e. from a somewhat different material to the casing of the delivery device  22 . Two-component injection molding makes it possible to produce the ring fastener, together with its slotted area and the slits  29  in a single production step, namely the injection molding of the casing. The ring fastener  29  does not constitute a separate part, which has to be separately fitted at the installation stage. 
   Particularly in the case of small pumps with short delivery devices  22  and relatively short fastening portions  23  and  24 , it is advantageous to use such ring fasteners  26 . The overall height required for them for the formation of a reliable hold and a fluid-tight, permanent connection is only approximately 10 mm. 
   Having described, with reference to  FIGS. 1-3 , the fastening features for the delivery device in the medium container schematically and partially in detail,  FIG. 4  shows a preferred embodiment of the dispenser using the features described before with reference to FIG.  2  and FIG.  3 . It shows a dispenser  20  with a medium container  21  and a delivery device  22 , comprising a pusher  41  and a pump body  42  with including a pump cylinder  43  surrounding a pump chamber  44 . The lower end of the pump cylinder  41  houses a suction valve  45 , designed as a ball valve and has an opening connected to a suction pipe  46  extending into the container. 
   In the pump chamber  44 , a piston  47  is guided by a sealing lip  48 . The piston consists of an annular sleeve with the sealing lip  48  on one end and a compressible hose-like sleeve portion  49  on the other end, which is fastened to a hollow pusher rod  50 . In between sealing lip  48  and sleeve portion  49  there is a conical part, which has a double valve function. Its outside valve seat  51  cooperates with an inner lower edge  52  of a cylinder insert  53 , which is in tight snap connection  54  with the pump cylinder  53  to form a ventilation valve. An inner edge  55  of the piston cooperates with a valve seat  56  of the piston rod  57  to form an outlet valve of the pump. A helical spring  58  urges the piston  57  with its valve seat  56  against the edge  55 , thereby closing the outlet valve  59  and also the valve seat  51  against the sealing edge  52  in order to close the ventilation valve which is necessary to compensate the volume of the dispensed medium by ambient air. 
   The pump cylinder  53  has a flange  60  lying on the end face  61  of the bottle neck  23  of the medium container  21 . The pump cylinder has a venting opening  32  in its outer wall, which is in communication with venting valve  51 ,  52 . 
   The pusher has, in the embodiment shown here, the form of an inverted cup with a cylindrical jacket  62 , an operating surface  63  and an inner hollow socket  64 , which is in fluid connection with the outlet nozzle  31 . The pusher rod  50  is pressed into the socket  64  and provides a fluid connection from the pump to the nozzle by its inner channel  65  and also transfers the operating force F from the pusher to the pump piston. 
   The outer wall of the pump body, namely in the embodiment shown here the pump cylinder  43 , has an outer layer of the soft plastic material as described before. It is integral with the inner harder and more stable wall material of the pump cylinder as described with reference to FIG.  2  and is produced by a 2-component molding procedure. The layer is applied to the pump body and covers its outer wall from the lower side of the flange  60  to beyond the lower end of the fastening surface  67  of the bottle neck ending in a conical part  68 .  FIG. 4  shows one of the slits  29  which are formed in the layer  26  beginning at the annular, unslotted closed portion  27 , thereby connecting the ventilation opening  32  to the inside of the container. 
   The delivery device  22  is mounted on the container  21  as follows: 
   After filling the container  21  with the medium the delivery device  22  is pushed from above into the container opening surrounded by the bottle neck  23 . This is done by exerting a mounting pressure on the operating surface  63  of the pusher  41 , e.g. by hydraulic plunger. Due to the oversize diameter of the layer  26  with regards to the container opening a considerable pressure will be necessary. This will cause the pump to be operated. Piston  47  will slide down in the pump chamber against the force of spring  58 . Since the pump chamber  44  is not yet filled with liquid, but only with air, there will be only a very faible compression force in chamber  44 . At the end of the pump stroke sealing lip  48  will abut a shoulder  69  in the pump cylinder causing the sleeve portion  49  of piston  47  to be compressed by bulging, thereby opening outlet valve  59 . This allows the compressed air in chamber  44  to escape to channel  65  and nozzle  31 . At the same time the ventilation valve  51 ,  52  has opened connecting the inside of the medium container with the atmosphere. The full mounting pressure exerted in direction F is however not transferred to the pump body via the piston  47 , which may otherwise impair the function of the sealing lip  48 . Therefore there are cooperating abutting or stop surfaces  70 ,  71  at the lower end of the pusher jacket  62  and the flange  60 . Additionally or instead the lower face  72  of socket  64  could constitute such abutment or stop in cooperation with the upper face of  73  of insert  53 . In order to assure this, the distance a between the stops  70 ,  71  or  72 ,  73  is only by a very small amount larger then the distance b between the sealing lip  48  and shoulder  69 , both regarded in the unoperated rest position shown in FIG.  4 . This ensures that the piston is only lifted and charged so much that the outlet valve  59  can open to prime the pump, but the full mounting force or pressure is directly transferred from pusher  41  via the stops or abutting surfaces  70 ,  71  or  72 ,  73  to the pump body. 
   When pressing the pump body into the bottle neck the somewhat oversized layer  26  deforms and is displaced elastically partially into the slits  29  and partially by forming a bead  74  inside the container. Both are forming elastic reserves to maintain a considerable holding force and pressure between fastening surface  67  of the bottle neck and the corresponding surface  75  of the layer  26 . The slits which can be one or more, and which are parallel to the axis  40  or only slightly deviating therefrom, create expansion chambers which also compensate manufacturing tolerances and avoid undue stress on the outer wall, e.g. the pump cylinder  43 . The holding force is strengthened by an outwardly curved shape of fastening  67  of the container opening creating projecting ring parts at the upper and lower end of the bottle neck as shown in FIG.  4 . 
   At the end of the mounting the flange  60  is supported on the end face  61  of the container and the delivery device is thus fixedly mounted on the container. 
   When the mounting pressure is released spring  58  pushes back the piston rod and therewith the piston. The outlet valve closes and liquid is sucked into the pump chamber  44  through suction pipe  46 . The venting valve which did also allow to escape a possible air pressure in the container due to the insertion of the delivery device is closed again and the delivery device is now completely tightening the container.