Medication delivery device with telescopic piston rod

• US 20020107487A1
• Filed: 10/25/2001
• Published: 08/08/2002
• Est. Priority Date: 10/27/2000
• Status: Active Grant

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Preuthun, Jan Harald
• Granted Patent: US 6,508,788 B2
• Time in Patent Office: Days
• US Class Current: 604/218
• CPC Class Codes: A61M 2205/6018 providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump

Abstract

A medication delivery device comprising a container containing a fluid medicament. The medicament is expelled from the container by moving forward an elastomeric piston inside the cartridge. The piston is moved forward by a telescopic piston rod, which can either be centrally located in the container or eccentric located. One end of the telescopic piston rod abuts the elastomeric piston either by itself or through an additional plate. The abutment having a friction large enough to prevent a lower part of the telescopic rod from rotating. In order to prevent the elastomeric piston from rotating inside the container a second telescopic piston rod is provided parallel with the first telescopic piston rod.

Claims

1. A medication delivery device for delivering medicine or other fluent material to a mammal body, having a housing (1) accommodating a cartridge (2) containing an amount of said medicine, comprising:

an elastomeric piston (3) movable mounted in said cartridge (2), which elastomeric piston (3) is moved from a proximal end of said cartridge (2) towards a distal end of said cartridge (2) by rotating at least a part (5) of a first telescopic piston rod (4), which first telescopic piston rod (4) has a distal part (7) abutting said elastomeric piston (3) and a proximal part (5) rotatably mounted in said housing (1) and a plurality of parts (6) there between, said parts (5,6,7) being connected to each other by mating threads,

drive means (8,9,10,11) for rotating said first telescopic piston rod (4), such that said elastomeric piston (3) moves forward inside said cartridge (2) and expels an amount of said medicine, and

means preventing said elastomeric piston (3) from rotating when said part (5) of said first telescopic piston rod (4) is rotated,

characterized in that

said means preventing said elastomeric piston (3) from rotating when at least a part (5) of said first telescopic piston rod (4) is rotated comprises an additional telescopic piston rod (14) having a proximal end mounted in said housing (1) and a distal end abutting said elastomeric piston (3).

2. A medication delivery device according to claim 1, characterized in that said additional telescopic piston rod (14) is rotatably mounted in said housing (1).

3. A medication delivery device according to claim 1 or 2, characterized in that said additional telescopic piston rod (14) extends parallel with said first piston rod (4) inside said cartridge (2).

4. A medication delivery device according to anyone of the claims 1-3, characterized in that said first telescopic piston rod (4) and said additional telescopic piston rod (14) is connected to each other through a synchronisation gear (20,21), such that both telescopic pistons rods (4,14) rotates with the same rotational speed, and that one of said telescopic piston rods (4,14) is rotated by an electrical motor (8) which drives one of said telescopic piston rod (4,14) through a driving gear (9,10,11).

5. A medication delivery device according to anyone of the claims 1-4, characterized in that said first telescopic piston rod 4 and said additional telescopic piston rod (14) each comprises of three parts (5,6,7,15,16,17);

a first part (5,15) having an interior thread, a third part (7,17) having an exterior thread and an intermediate second part (6,16) having an exterior thread mating said interior thread of said first part (5,15) and an interior thread mating said exterior thread of said third part (7,17).

6. A medication delivery device according to claim 5, characterized in that said first part (5) of said first telescopic piston rod (4) and said first part (15) of said additional telescopic piston rod (14) is located at said proximal end of said cartridge (2), and that said third part (7) of said first telescopic piston rod (4) and said third part (17) of said additional telescopic piston rod (14) is moving towards said distal end of said cartridge (2).

7. A medication delivery device according to claim 5 or 6, characterized in that the direction of said threads of said first telescopic piston rod (4) and said additional telescopic piston rod (14) is such that said distal end of each telescopic piston rod (4,14) travels in the same direction inside said cartridge (2) when one of said telescopic piston rods (4,14) is rotated.

8. A medication delivery device according to claim 7, characterized in that said first telescopic piston (4) and said additional telescopic piston rod (14) rotates in the same direction.

9. A medication delivery device according to claim 7, characterized in that said first telescopic piston (4) and said additional telescopic piston rod (14) rotates in opposite directions.

10. A medication delivery device according to anyone of the preceding claims, characterized in that said first telescopic piston rod (4) at said distal end is connected to said distal end of said additional telescopic piston rod (14) preferably through a circular plate (18) abutting said elastomeric piston (3) inside said cartridge (2).