INJECTION MOLDED CANNULA SYSTEM

Abstract

Disclosed herein is a cannula system including a soft cannula 10 and a cannula holder for holding the soft cannula. The cannula holder has a compressor and a body. The body contains a mounting structure and a cavity for holding a septum. The soft cannula is threaded on the mounting structure. Furthermore, the compressor circumferentially surrounds the mounting structure and at least parts of the body. The compressor provides an internal material tension for exerting a compression force on the soft cannula and the mounting structure.

Claims

1. A method for manufacturing a cannula system, the method comprising: providing a body having a mounting structure, the body being mounted onto a molding core pin, wherein the body is optionally provided by injection molding onto the molding core pin; positioning a soft cannula on the mounting structure; injection molding a compressor on the soft cannula and at least part of the body, wherein the compressor circumferentially surrounds the mounting structure, at least part of the soft cannula and at least part of the body; cooling the compressor and thereby providing an internal material tension of the compressor, and removing the molding core pin.

2. The method according to claim 1, wherein only a distal end area of the soft cannula is positioned on the mounting structure of the body and wherein the compressor optionally circumferentially surrounds only the distal end area of the soft cannula.

3. The method according to claim 2, wherein the distal end area of the soft cannula is provided with a lock for establishing a form lock and/or an adhesive bond between the soft cannula and the compressor.

4. The method according to claim 3, wherein, prior to positioning the soft cannula on the mounting structure of the body, the lock is generated at the distal end area of the soft cannula.

5. The method according to claim 3, wherein the lock includes at least one protrusion.

6. The method according to claim 5, wherein the lock is selected from the group consisting of (i) a protruding collar arranged at the most distal part of the distal end area and (ii) at least one hole in the soft cannula.

7. The method according to claim 6, wherein the lock includes the at least one hole in the soft cannula, and wherein the compressor protrudes into the at least one hole to thereby improve a seal between the compressor and the soft cannula.

8. The method according to claim 2, wherein the distal end area of the soft cannula has a larger diameter than the rest of the cannula before the cannula is positioned on the mounting structure.

9. The method according to claim 1, wherein the internal material tension of the compressor exerts a radially inward compression force and/or wherein the internal material tension of the compressor compresses the soft cannula.

10. The method according to claim 1, wherein the body and the compressor and/or wherein the compressor and the soft cannula form a bonded connection during injection molding of the compressor.

11. A cannula system, comprising: a soft cannula; a cannula holder configured to hold the soft cannula, the cannula holder comprising a compressor and a body; the body having a mounting structure and a cavity for holding a septum, wherein the soft cannula is positioned on the mounting structure; and the compressor circumferentially surrounding the mounting structure and at least part of the body, wherein the compressor provides an internal material tension for exerting a compression force on the soft cannula and the mounting structure.

12. The cannula system according to claim 11, wherein only a distal end area of the soft cannula is positioned on the mounting structure and wherein the compressor circumferentially surrounds the distal end area of the soft cannula.

13. The cannula system according to claim 12, wherein the distal end area of the soft cannula comprises a lock that provides a form lock and/or an adhesive bond between the soft cannula and the compressor.

14. The cannula system according to claim 13, wherein the lock is selected from the group consisting of (i) a protrusion protruding from the most distal part of the distal end area and (ii) at least one hole.

15. The cannula system of claim 14, wherein the lock includes the protrusion and the protrusion comprises a collar.

16. The cannula of claim 13, wherein the lock includes at least one hole in the soft cannula, and wherein the compressor protrudes into the at least one hole to thereby improve a seal between the compressor and the soft cannula.

17. The cannula system according to claim 10, wherein the distal end area of the soft cannula has a larger diameter than the rest of the soft cannula.

18. The cannula system according to claim 10, wherein the compressor compresses at least the distal end area of the soft cannula and/or wherein the body and the compressor are connected by a bonded connection and/or wherein the soft cannula and the compressor are connected by a bonded connection.

19. A method of using an infusion set, comprising: providing a cannula system according to claim 11; and using the cannula system in the infusion set.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0043] FIG. 1 shows a cross-sectional view of a cannula system in accordance to an embodiment of this disclosure;

[0044] FIGS. 2a to 2c schematically show the manufacturing method of a cannula system according to an embodiment of this disclosure;

[0045] FIG. 3 shows a cross-sectional view of a cannula system in accordance to another embodiment of this disclosure; and

[0046] FIG. 4 shows a cross-sectional view of a cannula system in accordance to another embodiment of this disclosure.

DESCRIPTION

[0047] The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure.

[0048] FIG. 1 shows an advantageous embodiment of a cannula system 1 according to this disclosure. Cannula system 1 comprises soft cannula 10 and a cannula unit (also referred to herein as a “cannula holder”) 12 for holding soft cannula 10. The cannula holder includes compressing unit (“compressor”) 20 and body unit (“body”) 30. Body 30 further comprises mounting structure 31 and cavity 32 for receiving a septum. Distal part 11 of soft cannula 10 is threaded on mounting structure 31. The diameter of distal end area 11 of soft cannula 10 is larger than the diameter of the rest of the soft cannula. Compressor 20 circumferentially surrounds distal end area 11 of soft cannula 10, mounting structure 31 and also an additional part of body 30. As shown in FIG. 1, more than ⅓ of the outer surface of the body are circumferentially surrounded by compressor 20.

[0049] As indicated by the arrows, the compressor 20 has an internal material tension, thereby exerting a radially inwards directed compression force on the distal end area of the soft cannula and the mounting structure. As a result, a particular tight connection between soft cannula 10, mounting structure 31 and compressor 20 is achieved. Furthermore, as can be readily seen in FIG. 1, the wall thickness of distal end area 11 of soft cannula 10 is smaller than the wall thickness of the rest of soft cannula 10. In addition, as indicated by the arrows, distal end area 11 of soft cannula 10 is compressed by the compression force exerted by compressor 20. Compressor 20 and body 30 are connected by a bonding connection at their contact area. As a result, a reliable and sealingly tight connection is established.

[0050] FIGS. 2a to 2c depict certain steps of a method of manufacturing a cannula system according to an advantageous embodiment of this disclosure. As shown in FIG. 2a, body 30 with mounting structure 31 is injection molded onto a molding core pin 40 (mold not shown). In a following step, distal end area 11 of soft cannula 10 is threaded on mounting structure 31 (FIG. 2b). Afterwards, compressor 20 is injection molded on the distal end area of the soft cannula, on the mounting structure and also on further parts of body 30 (FIG. 2c, mold not shown). As the compressor is at least partially injection molded on body 30, any production imprecision of the proximal face of the body unit is less relevant, as the compressor is necessarily complementary to those parts of the body 30. Once compressor has been injection molded, molding core pin 40 can be removed and the compressor can be cooled, upon which an internal material tension is established, thereby exerting a force on distal end area 11 of soft cannula 10 and mounting structure 31. Generally, the cooling can be performed in the mold and/or the cooling may be achieved by active cooling. Thus, the compressor is not allowed to cool to room temperature by itself, but actively cooled, particularly by using a cooling medium. Such rapid cooling enhances the internal material tension. The two-step injection molding sequence can be performed significantly faster than the methods for manufacturing cannula unit as known in the state of the art.

[0051] FIG. 3 shows another advantageous embodiment of a cannula system 1 according to this disclosure. Cannula system 1 comprises soft cannula 10 and a cannula unit containing compressor 20 and body 30. Body 30 comprises mounting structure 31 on which distal end area 11 of the soft cannula 10 is threaded. In the particular embodiment shown, distal end area 11 comprises two holes 12a as locking structures, which are provided as through bores. The dimension of holes 12a are drawn in exaggeration for demonstrative purposes only. Even though the arrows indicating the compressing force are not shown in FIG. 3 (see FIG. 1), also in this embodiment with holes 12a, a compressing force is exerted by the compressor on soft cannula 10. As can be seen, parts of the compressor 20 enter holes 12a during injection molding. After the compressor is cooled, a tighter sealing between compressor 20 and soft cannula 10 is achieved. Additionally, the fixation of soft cannula 10 within thin cannula system is improved.

[0052] FIG. 4 depicts another embodiment of cannula system 1, with soft cannula 10 and a cannula unit comprising compressor 20 and body 30 with mounting structure 31. In general, the mounting structure may be a protrusion of the body, such as a nipple. Distal end area 11 of soft cannula 10 comprises collar 12b as a locking structure or lock, which establishes a form lock between soft cannula 10 and compressor 20. Collar 12b is circumferentially arranged at the most distal part of distal end area 11. During injection molding of compressor 20, the material is provided around collar 12b. As a result, soft cannula 11 is anchored within compressor 20, thereby both increasing fixation of the cannula within the cannula system and the sealing between the cannula and the compressor.

[0053] While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.