Technical Field The invention relates to a drop dispenser ac- cording to the preamble of the independent claim.

Drop dispensers of this kind, as described in WO 02/072444 Al, are used for dispensing liquids in drops. A typical application are pharmaceutical products, for example eye drops, or cosmetics. The drop dispensers usually comprise a flexible container or are designed as a cap for a flexible container. In contrast to drop dis- pensers for inflexible containers there is no opening to let air from the outside into the container during dis- pensing.

Background Art Many known drop dispensers of this kind are not easy to use, because the drop dispensing is not pre- cise and not easily controllable. Many times the size of the drops is not correct because it is dependent on the kind and the state of the liquid, the position of the dispenser, the speed of the dispensing and/or the pres- sure applied to the container. In addition, because of the bad controllability the user might not be able to dispense the right number of drops. When used for pharma- ceutical products this results in wrong dosages, which makes known dispensers unsuitable for certain applica- tions where a correct dosage is essential. These problems are especially significant, if the drop dispensers are used by elderly people with reduced cognitive and motoric skills. In many cases manufacturing costs of known drop dispensers are unnecessary high because they comprise many parts and in particular parts which cannot be easily

produced by efficient processes, as for example by injec- tion molding.

Disclosure of Invention A problem to be solved by the present inven- tion lies therefore in providing a drop dispenser which avoids the problems described above at least partially.

This problem is solved by independent claim 1 by providing a drop dispenser with an insert element, wherein a throttling passage is formed between the insert element and a wall. The inventive drop dispenser is pre- cise, easy to use and can be manufactured at a low price.

Brief Description of Drawings Further preferred features and aspects of the present invention are described in the dependent claims as well as in the following description, which makes ref- erence to the enclosed figures. These figures show: Fig. 1 a vertical cross-sectional view of a preferred embodiment of a drop dispenser according to the invention, Fig. 2 the drop dispenser of fig. 1, with a cap, Fig. 3 a three dimensional view of the insert element of the drop dispenser shown in fig. 1, Fig. 4 a three dimensional view of a further preferred embodiment of an insert element for a drop dis- penser according to the invention, Fig. 5 a three dimensional partially sec- tional view of the drop dispenser of fig. 1, Fig. 6 an alternative spout element for the drop dispenser of Fig. 1.

Fig. 7 the spout element of Fig. 6 in a cross-sectional view,

Fig. 8 the spout element of Fig. 6 in a view from below, Fig. 9 a vertical cross-sectional view of a further embodiment of a drop dispenser according to the invention, Fig. 10 a three dimensional view of the in- sert element of the drop dispenser shown in fig. 9, Fig. 11 a schematic view from below of the insert element of the drop dispenser shown in fig. 9, Fig. 12 a schematic side view of the insert element of the drop dispenser shown in fig. 9, Fig. 13 a three dimensional partially sec- tional view of the drop dispenser of fig. 9, Fig. 14 a vertical cross-sectional view of a further embodiment of a drop dispenser according to the invention with a mounting aid, Fig. 15 a side view of the insert element with mounting aid of fig. 14, Fig. 16 a horizontal cross-sectional view of the insert element of fig. 15, Fig. 17 a horizontal cross-sectional view of an alternative embodiment of the insert element, Fig. 18 the insert element of fig. 15 in a three dimensional view, Fig. 19 the container of fig. 14 in a three dimensional view, Fig. 20 the container of fig. 14 mounted on a mandrel as during production process according to the in- vention, Fig. 21 a three dimensional partially sec- tional view of the arrangement of fig. 20.

Best Mode for Carrying Out the Invention A vertical cross-sectional view of a pre- ferred embodiment of a drop dispenser 3 according to the invention is shown in fig. 1. The drop dispenser 3 com-

prises an insert element 1, a spout element 2 and part of a container 9. Insert element 1 and spout element 2 are preferably injection molded using thermoplastic synthetic material. The insert element 1 is preferably harder than the spout element 2. This is advantageous because the in- sert element 1 and in particular its edges slightly push into the wall 15 of the spout element 2 and the insert element 1 stays in its position without additional fixa- tion means. Vice versa, the spout element 2 can be harder than the insert element 1. Alternatively the insert ele- ment 1 can be held by snap-in means, in particular a snap-in rim, or with glue. The container 9 preferably has the shape of a tube or a bottle, in particular a tube or bottle which is at least partially cylindrical or oval and is made at least partially from a plastic material and/or as a laminate. It is designed for holding a liq- uid, for example eye drops. The container 9 is at least partially flexible and the liquid in the container 9 can be pressurized by squeezing the container 9. For drop dispensing the container 9 is squeezed while being held such that spout element 3 is directed downwards. The liq- uid passes through throttling passage 11 into delivery passage 12 until there is enough liquid for a drop. The drop is in contact with tear-off edge 10 until it drops away. The throttling passage 11 is formed between the in- sert element 1 and the spout element 2. The insert ele- ment 1 is surrounded and in particular partially enclosed by walls 15 of the spout element 2. These walls 15 or in- ner surfaces comprise two walls, an annular side wall and a circular or discoidal end wall. The insert element 1 comprises a lateral notch 6, a transversal notch 7, and preferably a bore 8. The notches, or grooves, are de- signed to form together with walls 15 of the inside of the spout element 12 the channels of the throttling pas- sage 11. The throttling passage 11 goes first along the lateral notch 6, then along the transversal notch 7 and ends centrally at the bore 8, which is at the inner end

of the delivery passage 12. Between lateral notch 6 and transversal notch 7 the throttling passage 11 has a sharp bend or more precisely a 90 degree sharp bend. The throt- tling passage 11 and subsequent turbulences cause a re- duction of pressure and flow rate of the liquid being dispensed. The flow rate substantially stays within a certain range independent of the pressure applied to the container 9 and due to the turbulences even at a high pressure the liquid is not dispensed as a jet or spout which would interfere with the drop formation. The deliv- ery passage 12 is substantially conical, wherein the largest diameter is at the distal end of the spout ele- ment 2. The container 9 can be closed with a cap, for which there is a thread 5.

Fig. 2 shows the drop dispenser of fig. 1, with a cap 16, without the insert element 1. The cap 16 has an inside thread which matches the outside thread 5 of the container 9. The thread 5 is in particular an M9- thread. The container 9 is tightened by the cap 16 being in full contact with the tear-off rim 10. The cap 16 also protects the spout element 2 against contamination from the outside. The cap 16 has for better handling and for aesthetic reasons an outside surface at a radius which is substantially larger than the radius of the spout element 2. To save plastic material and to avoid sink marks, the cap 16 comprises an inner wall and an outer wall with an annular recess in between.

Fig. 3 shows a three dimensional view of the insert element 1 of the drop dispenser shown in fig. 1.

It is substantially cylindrical. It comprises a lateral notch 6 extending in the direction of the axis of the cylinder from a first circular surface of the cylinder to a second circular surface of the cylinder, a transversal notch 7 extending in radial direction from the end of the lateral notch 6 to the center of said second circular surface and a bore 8 in the center of said second circu- lar surface. The depth of the notches 6,7 can be varied,

in particular to adapt the dispenser to the properties of the liquid to be dispensed and/or a desired speed of drop formation. In particular an adaptation on whether the liquid is high-molecular or not is possible. Alterna- tively the throttling passage can also comprise a second path, in particular formed by a second vertical and a second transversal notch. The insert element can as well be plate-shaped, in particular disk-shaped instead of the shown cylindrical shape.

Fig. 4 shows a three dimensional view of a further preferred embodiment of an insert element 1 for a drop dispenser 3 according to the invention. It is sub- stantially cylindrical. The lateral notch 6 also starts at the first circular surface of the cylinder, but in contrast to the insert element of fig. 3 ends in the mid- dle of the cylinder at a transversal bore 13 and does not extend all the way to the second circular surface. The transversal bore 13 has a connection to a central bore 14. In an embodiment of a drop dispenser comprising the shown insert element 1, for example based on the spout element 2 and container 9 shown in fig. 1, the throttling passage 11 is only formed partially between the insert element 1 and the wall 15. Alternatively the central bore 14 and the lateral notch 6 can be designed such that they overlap and that there is no transversal bore 13 neces- sary.

Fig. 5 shows a three dimensional partially sectional view of the drop dispenser of fig. 1.

Fig. 6, Fig. 7 and Fig. 8 show different views or sections of a spout element 2 suitable for the drop dispenser of Fig. 1. In contrast to the spout ele- ment 2 show in fig. 1 this spout element 2 has cavities 17. Because of these cavities 17 there is less thermo- plastic material needed, and it is less likely that the workpiece gets sink marks while cooling down after injec- tion molding. The spout element 2 shown in fig. 6 to 8 is preferably combined with an insert element 1 as shown in

Fig. 4 where the throttling passage has only a central outlet. This has the advantage, that the cavities are not connected to the passages and do not get filled with liq- uid which might deteriorate therein.

Fig. 9 shows a vertical cross-sectional view of a further embodiment of a drop dispenser according to the invention. In contrast to the embodiment of fig. 1, the tip or spout element 2 is designed elongated, as a cannula to allow a locally more precise application of the drops. The outside surface of the spout element 2 is conical having the smallest radius at its distal end. The insert element 1 only comprises a lateral notch 6. The throttling passage 11 ends laterally in the delivery pas- sage 12. These turbulences are favorable for drop dis- pensing as already described referring to fig. 1. The de- livery passage 12 is also conical as in the embodiment shown in fig. 1, but the smallest radius is at the distal end of the spout element 2. During drop dispensing there are turbulences in the area where the liquid emerges from the throttling passage 11 into the delivery passage 12.

The spout element 2 and the container 9 are one piece.

The container 9 is preferably a laminate tube.

Fig. 10 shows a three dimensional view of the insert element 1 of the drop dispenser shown in fig. 9.

The insert element 1 is conical and has a lateral notch 6 extending from the first circular surface to the second circular surface, substantially in the direction of the axis of the insert element 1. The actual direction is slightly inclined towards or away from the axis because of the conical shape of the element. Alternatively the lateral notch 6 can also be inclined sideways and, if a large inclination angle is selected, even have the shape of a spiral.

Fig. 11 shows a schematic view from below of the insert element 1 of the drop dispenser shown in fig.

9. The notch 6 has a v-profile, but can also be designed with a u-profile or other profiles, in particular pro-

files which are suitable to be formed during injection molding of the insert element 1. Instead of by a notch, the throttling passage can also be formed by leaving out a segment of the circular profile of the insert element 1 or by cutting away such a segment.

Fig. 12 shows a schematic side view of the insert element 1 of the drop dispenser 3 shown in fig. 9.

Fig. 13 shows a three dimensional partially sectional view of the drop dispenser 3 of fig. 9.

Fig. 14 shows a vertical cross-sectional view of a further embodiment of a drop dispenser 3 according to the invention. It comprises a mounting aid 18. The mounting aid 18 is formed by an elongation of the insert element 1. The mounting aid 18 serves as a handle or grip for inserting the insert element 1 into the spout element 2 during the production process. The mounting aid 18 is designed in such a way that it does not interfere with the functioning of the drop dispenser 3. It can therefore remain attached to the drop dispenser 3 and does not have to be removed to finish the production process.

Fig. 15 shows a side view of the insert ele- ment 1 with mounting aid 18 of fig. 14. The mounting aid 18 comprises a cylindrical shaft 22 and an annulus 23.

The shaft 22 is designed to fit into a cylindrical bore of a mandrel or to be held by a gripping device. The an- nulus 23 functions as a stop edge. It prevents the mount- ing aid 18 from sinking to far into the bore of the man- drel. The annulus 23 also prevents the insert element 1 from being pushed to far into the delivery passage 12. In this case the annulus 23 contacts the inside of the con- tainer 9 along a circular angular surface 20. A recess 21 assures that liquid can still pass from the interior of the container body to the throttling passage 11 no matter how tight the angular surface 20 is pressed to the inte- rior surface of the container 9. Between the annulus 23 and actual insert portion of the insert element 1 there is an annular notch 19. Due to this annular notch 19

there is an edge, which"hooks"into the interior surface of the spout element 2 and thereby holds the insert ele- ment 1 in its place. As already mentioned above this ef- fect can be enforced by making the insert element 1 harder than the spout element 2. There is an angular sur- face at both ends of the insert element 1 for making in- serting it into the spout element 2 and the mandrel eas- ier. The lateral notch 6 gets bigger following it along the fluid path to its distal end. This causes the fluid to slow down and not to enter the delivery passage 12 as a jet or spout.

Fig. 16 shows a horizontal cross-sectional view of the insert element with mounting aid of fig. 15.

The annular notch 19 goes all around the insert element 1.

Fig. 17 shows a horizontal cross-sectional view of an alternative embodiment of the insert element 1. In this embodiment the annular notch 19 is only par- tial, leaving two sections of the circumference without a notch.

Fig. 18 shows the insert element of fig. 15 in a three dimensional view.

Fig. 19 shows the container of fig. 14 in a three dimensional, partially sectional view.

Fig. 20 shows the container of fig. 14 during the production process. In the production the insert ele- ment 1 is first securely placed on the mandrel 24 by in- serting its shaft 22 into a central bore in the mandrel.

Then the container 9 with spout element 2 is pushed over the mandrel 24. In doing so the insert element 1 is pushed into the delivery passage 12 of the drop dispenser 3. This state is shown in fig. 18. Then a cap may be screwed or pushed on. Afterwards the container 9 with drop dispenser 3, now comprising spout element 2 and in- sert element 1, is removed from the mandrel 24 and is passed on to the further production steps for producing a closed and filled container, in particular a tube. The

process described above is not limited to a static man- drel 24. Instead, for example, the container 9 may be held static, while the mandrel 24 with insert element 1 is pressed into it.

Fig. 21 shows a three dimensional partially sectional view of the arrangement of fig. 20.

The drop dispenser according to the invention is well suited to furnish existing lines of containers. A typical container to be combined with the drop dispenser according to the invention is the"NEOPAC POLYFOILO" laminate tube. Diameters of this tube are 10,13. 5,16 or 19 mm. The thickness of the wall is 0.3 or 0.5 mm. The length of the tube can be varied, typically in a range between 35 and 80 mm. The volume varies accordingly be- tween 1.5 and 15 ml.

It is to be noted, that additional features and variations described in respect to the embodiment shown in a certain figure can also be applied to the em- bodiments shown in other figures.