Medication delivery device with bended piston rod

• US 20020091358A1
• Filed: 10/04/2001
• Published: 07/11/2002
• Est. Priority Date: 10/05/2000
• Status: Active Grant

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Klitmose, Lars Peter
• Granted Patent: US 6,537,251 B2
• Time in Patent Office: Days
• US Class Current: 604/131
• CPC Class Codes: A61M 2005/31518 designed to reduce the overall size of an injection device, e.g. using flexible or pivotally connected chain-like rod members
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: B05C 17/0113 the piston rod being flexible or articulated B05C17/0109 takes precedence

Abstract

The invention relates to: A portable medication delivery device (1) comprising a medication cartridge (11) having an outlet (111) and a movable piston (112), and a housing (12) for holding said cartridge, and a flexible piston rod (13) being operable to engage and displace said piston along an axis (113) of said cartridge, and guiding means (14) for bending said piston rod away from said axis, and actuating means (15), and driving means (16, 17) for transferring movement from said actuating means to said piston rod, said driving means including a driving wheel (17) for displacing the piston rod (13), said flexible piston rod comprising regularly spaced first members (330; 331; 332) adapted to mechanically cooperate with corresponding second members (171) on said driving wheel. The object of the present invention is to provide a medication delivery system that combines compactness with an improved accuracy. The problem is solved in that said flexible piston rod (13) exhibits a linear or approximately linear path between said driving wheel (17) and said piston (112). This has the advantage of yielding a compact, low-weight device with an improved dose accuracy. The invention may e.g. be used in injection or infusion devices for a person'"'"'s self-treatment of a disease such as diabetes.

Claims

1. A portable medication delivery device (1) comprising a medication cartridge (11) having an outlet (111) and a movable piston (112), and a housing (12) for holding said cartridge, and a flexible piston rod (13) being operable to engage and displace said piston along an axis (113) of said cartridge, and guiding means (14) for bending said piston rod away from said axis, and actuating means (15), and driving means (16, 17) for transferring movement from said actuating means to said piston rod, said driving means including a driving wheel (17) for displacing the piston rod (13), said flexible piston rod comprising regularly spaced first members (330;

331;

332) adapted to mechanically cooperate with corresponding second members (171) on said driving wheel,

characterized in that said flexible piston rod (13) exhibits a linear or approximately linear path between said driving wheel (17) and said piston (112).

2. A portable medication delivery device according to claim 1,

characterized in that

said flexible piston rod (13) remains in a fully reversible elastic state during cooperation with said driving wheel (17) and said guiding means (14).

3. A portable medication delivery device according to claim 1 or 2,

characterized in that

the surface (133) of said flexible piston rod (13) in a transversal cross-section is adapted to follow the surface (172) of said driving wheel (17) fully or partially.

4. A portable medication delivery device according to any one of claims 1-3,

characterized in that

said guiding means (14;

36) also work as a take-up spool for storing the unused part of the piston rod (13;

33).

5. A portable medication delivery device according to any one of claims 1-4,

characterized in that

said driving wheel and said guiding means are the same physical unit (17;

36).

6. A portable medication delivery device according to any one of claims 1-4,

characterized in that

said driving wheel (17) is located after said guiding means (14) in a downstream direction (1131) towards said cartridge (11).

7. A portable medication delivery device according to any one of claims 1-6,

characterized in that

said piston rod (13) touches the inner walls in an axial direction (113) of said cartridge (11) at one or more points in a transversal cross-section of said piston rod.

8. A portable medication delivery device according to claim 7,

characterized in that

the longitudinal edges (131, 132) of said piston rod (13) in the cartridge (11) touch the inner walls of said cartridge.

9. A portable medication delivery device according to any one of claims 1-8,

characterized in that

said flexible piston rod (13) is tape-shaped.

10. A portable medication delivery device according to any one of claims 1-9,

characterized in that

said flexible piston rod (13) consists of two separate tape-shaped bodies that are joined together at one or more points in a transversal cross-section.

11. A portable medication delivery device according to claim 10,

characterized in that

said two separate tape-shaped bodies (337, 338) are joined together in the central point (334) of a transversal cross-section.

12. A portable medication delivery device according claim 11,

characterized in that

the distance between said two tape-shaped bodies (337, 338) increases with increasing distance from said central point (334) when viewed in a transversal cross-section in a relaxed state.

13. A portable medication delivery device according to claim 10,

characterized in that

said two separate tape-shaped bodies (335, 336) are joined together at the edges (131, 132) of a transversal cross-section.

14. A portable medication delivery device according to claim 13,

characterized in that

said edges (131, 132) are joined by applying a coating layer to the surface of said separate tape-shaped bodies (335, 336).

15. A portable medication delivery device according to claim 13 or 14,

characterized in that

said two tape-shaped bodies (335, 336) describe an eye-shaped path when viewed in a transversal cross-section in a relaxed state.

16. A portable medication delivery device according to any one of claims 1-15,

characterized in that

said first members on said flexible piston rod comprise protruding members and said corresponding second members on said driving wheel comprise receiving members.

17. A portable medication delivery device according to any one of claims 1-15,

characterized in that

said first members comprise receiving members (330;

331;

332) and said corresponding second members comprise protruding members (171;

361).

18. A portable medication delivery device according to claim 17,

characterized in that

said first members comprise individually isolated indentations and said corresponding second members comprise individually isolated projecting members.

19. A portable medication delivery device according to claim 17,

characterized in that

said first members comprise individually isolated through holes (331;

3311;

3312) and said corresponding second members comprise individually isolated projecting members (171;

361).

20. A portable medication delivery device according to any one of claims 16-19,

characterized in that

said regularly spaced members (331) are located along a centre line (334) in the longitudinal direction of said flexible piston rod (33).

21. A portable medication delivery device according to claim 17,

characterized in that

said first members comprise individually isolated cuts (332) located at least along one periphery in the longitudinal direction of said flexible piston rod (33) and said corresponding second members comprise individually isolated projecting members.

22. A portable medication delivery device according to any one of claims 1-21,

characterized in that

the piston rod (13;

33) is at least partially made of a plastics material.

23. A portable medication delivery device according to any one of claims 1-22,

characterized in that

the piston rod (13;

33) is at least partially made of a metallic material.