Drive Mechanism for Drug Delivery Device

• US 20120283661A1
• Filed: 09/03/2010
• Published: 11/08/2012
• Est. Priority Date: 09/07/2009
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Inventors: Jugl, Michael, Sendatzki, Gunther, Teucher, Axel
• Granted Patent: US 10,232,122 B2
• Time in Patent Office: Days
• US Class Current: 604/224
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 2005/3103 Leak prevention means for distal end of syringes, i.e. syringe end for mounting a needle
• CPC Class Codes: A61M 2005/3112 Incorporating self-aspirating means, e.g. to provide flashback
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/31551 including axial movement of dose setting member
• CPC Class Codes: A61M 5/31561 using freely adjustable volume steps
• CPC Class Codes: A61M 5/31583 based on rotational translation, i.e. movement of piston rod is caused by relative rotation between the user activated actuator and the piston rod
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

A drive mechanism for a drug delivery device, preferably for a pen-type injector, the mechanism comprises a spindle (6) movable in a first direction during a delivery step, a splined portion (5, 11) operatively coupled to the spindle (6), and retraction means (12, 15, 16, 17, 20) acting on the splined portion (5, 11) at least at the end of the delivery step. Thereby, that after the delivery step the spindle (6) and/or the splined portion (5, 11) is moved in a second direction contrary to the first direction, such that the whole drive mechanism is relieved from stresses.

Claims

1. Drive mechanism for a drug delivery device, preferably for a pen-type injector, said mechanism comprising:

a spindle movable in a first direction during a delivery step,

a splined portion operatively coupled to said spindle, and

retraction means configured to act on said splined portion at least at the end of said delivery step such that after said delivery step said spindle and/or said splined portion is moved in a second direction contrary to said first direction.

2. Drive mechanism according to claim 1, wherein the retraction means is designed as an elastic portion or a spring element.

3. Drive mechanism according to claim 2, wherein the elastic portion is designed as a rubber element cushioning a splined socket engaging with the spindle.

4. Drive mechanism according to claim 1 further comprising a housing, with said retraction means being arranged between said splined portion and said housing.

5. Drive mechanism according to claim 1, wherein the retraction means and the splined portion are an integrally moulded component of the housing.

6. Drive mechanism according to claim 1, further comprising a cartridge holder for accommodating a cartridge containing a drug to be delivered, with said retraction means being arranged between said splined portion and said cartridge containing a drug to be delivered or said cartridge holder.

7. Drive mechanism according to claim 1, wherein the splined portion is designed as or a component of a driver acting on said spindle to move said spindle in the first direction during the delivery step.

8. Drive mechanism according to claim 1, wherein the splined portion is designed as a spindle nut rotationally fixed with respect to the housing.

9. Drive mechanism according to claim 1, wherein the spindle abuts to a hollow plug having a cup-shape and being of flexible material, said hollow plug acting in a cartridge containing a drug to be delivered.

10. Drive mechanism according to claim 9, wherein said hollow plug has a wall thickness of at least 1 mm, a bottom thickness of at least 1 mm and a clearance between the centreline perpendicular to the axial direction and the inner bottom face of at least 1 mm.

11. Drive mechanism according to claim 1, wherein the spindle is designed as a threaded piston rod and the first splined portion is designed as a nut-like element which is in engagement with the threaded piston rod, wherein the pitch of the two corresponding threads is chosen such that a small relative movement between the piston rod and the nut is allowed.