DRIVE MECHANISM FOR A DRUG DELIVERY DEVICE

• US 20130006193A1
• Filed: 09/29/2010
• Published: 01/03/2013
• Est. Priority Date: 09/30/2009
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Inventors: Veasey, Robert, Bilton, Simon Lewis, Jones, Christopher, Kouyoumjian, Garen, Macdonald, Catherine Anne
• Granted Patent: US 9,375,535 B2
• Time in Patent Office: Days
• US Class Current: 604/211
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 2005/2477 comprising means to reduce play of ampoule within ampoule holder, e.g. springs
• CPC Class Codes: A61M 2005/3126 Specific display means related to dosing
• 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 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• CPC Class Codes: A61M 5/31543 piston rod reset means, i.e. means for causing or facilitating retraction of piston rod to its starting position during cartridge change
• CPC Class Codes: A61M 5/31555 by purely axial movement of dose setting member, e.g. during setting or filling of a syringe
• CPC Class Codes: A61M 5/31556 Accuracy improving means
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button

Abstract

According to one aspect, a resettable drive assembly for a drug delivery device is provided for. The resettable drive assembly may comprise a housing having a proximal end and a distal end, a piston rod being rotatable with respect to the housing and being axially displaceable with respect to the housing between a proximal start position and a distal end position, a drive member for distally displacing the piston rod towards the end position when dispensing a dose, and a stop member. The drive assembly may be configured such that the drive member is operable to interact with the piston rod for forming an unlockable first interlock, the first interlock being operable to block proximal movement of the piston rod with respect to the drive member. The drive assembly may be configured such that the stop member is operable to interact with the piston rod for forming an unlockable second interlock, the second interlock being operable to block proximal movement of the piston rod with respect to the housing. The drive assembly may be configured such that, when the drive assembly is in a drive mode, the first and second interlocks are locked such that proximal movement of the piston rod from the end position to the start position is prevented by the first interlock and the second interlock. The drive assembly may be configured such that, for switching the drive assembly from the drive mode to a reset mode, the piston rod is rotatable with respect to the drive member for unlocking the first interlock and the stop member and the piston rod are rotatable with respect to each other for unlocking the second interlock. The drive assembly may be configured such that, when the drive assembly is in the reset mode, the first interlock and the second interlock are unlocked such that proximal movement of the piston rod to the start position is allowed. Further, a drug delivery device and a use of a spring are provided for.

Claims

1. A resettable drive assembly for a drug delivery device comprising

a housing having a proximal end and a distal end;

a piston rod being rotatable with respect to the housing and being axially displaceable with respect to the housing between a proximal start position and a distal end position;

a drive member for distally displacing the piston rod towards the end position when dispensing a dose; and

a stop member;

wherein the drive assembly is configured such that

the drive member is operable to interact with the piston rod for forming an unlockable first interlock, the first interlock being operable to block proximal movement of the piston rod with respect to the drive member;

the stop member is operable to interact with the piston rod for forming an unlockable second interlock, the second interlock being operable to block proximal movement of the piston rod with respect to the housing;

when the drive assembly is in a drive mode, the first and second interlocks are locked such that proximal movement of the piston rod from the end position to the start position is prevented by the first interlock and the second interlock;

for switching the drive assembly from the drive mode to a reset mode, the piston rod is rotatable with respect to the drive member for unlocking the first interlock and the stop member and the piston rod are rotatable with respect to each other for unlocking the second interlock; and

when the drive assembly is in the reset mode, the first interlock and the second interlock are unlocked such that proximal movement of the piston rod to the start position is allowed.

2. The resettable drive assembly of claim 1, wherein the drive member is axially displaceable with respect to the housing and rotationally locked with respect to the housing.

3. The resettable drive assembly of claim 1, wherein the stop member is axially and rotationally locked with respect to the housing.

4. The resettable drive assembly of claim 3, being configured such that the first interlock and the second interlock are unlockable by a rotation of the piston rod from a first angular position to a second angular position with respect to the housing.

5. The resettable drive assembly of claim 1, wherein the stop member is rotatable with respect to the housing.

6. The resettable drive assembly of claim 5, being configured such that the second interlock is unlockable by a rotation of the stop member in a first rotational direction with respect to the housing and the piston rod.

7. The resettable drive assembly of claim 6, wherein, when the second interlock is unlocked, the stop member is operable to interact with the piston rod such that the piston rod follows further rotational movement of the stop member in the first rotational direction with respect to the housing and the drive member for unlocking the first interlock.

8. The resettable drive assembly of claim 7, wherein the piston rod has a substantially axially extending protrusion, the substantially axially extending protrusion being operable to limit the angular range of motion of the stop member in the first rotational direction with respect to the piston rod.

9. The resettable drive assembly of one of claim 6, further comprising a spring, the spring interacting with the stop member to generate a resilient bias on the stop member for promoting rotation of the stop member in a second rotational direction, opposite to the first rotational direction, with respect to the housing when the drive assembly is in the drive mode and the spring interacting with the stop member to generate a resilient bias on the stop member for promoting rotation of the stop member in the first rotational direction with respect to the housing for unlocking the first interlock and the second interlock when switching the drive assembly to the reset mode.

10. The resettable drive assembly of claim 9, wherein

the stop member has a first part which is axially locked with respect to the housing and a second part which is axially displaceable with respect to the housing and resiliently biased in a first axial direction by means of the spring,

the drive assembly has a first diverter element and is configured for converting axial movement of the second part in the first axial direction into rotational movement of the stop member in the second rotational direction by means of interaction of the second part with the first diverter element when the drive assembly is in the drive mode, and

the drive assembly has a second diverter element and is configured for converting axial movement of the second part in the first axial direction into rotational movement of the stop member in the first rotational direction by means of interaction of the second part with the second diverter element when switching the drive assembly to the reset mode.

11. The resettable drive assembly of claim 10, wherein

the drive assembly has a first ramp and a second ramp, each ramp having a proximal end and a distal end,

the proximal ends of the first and second ramps face each other, and

the second part bears on the first ramp when the assembly is in the drive mode and the second part bears on the second ramp when switching the drive assembly to the reset mode.

12. The resettable drive assembly of claim 9, further comprising a reset member being releasably engageable with the housing, the reset member being operable to retain the drive assembly in the reset mode when it is engaged with the housing, wherein the spring is operable to generate a resilient bias in an axial direction on the reset member for locking the reset member in engagement with the housing when the drive assembly is in the reset mode.

13. A drug delivery device comprising the resettable drive assembly of claim 12, further comprising a detachable member for connecting to the housing, the detachable member being one of a cartridge and a cartridge holder, wherein the detachable member is operable to interact with the reset member such that, when connecting the detachable member to the housing, the engagement of the reset member with the housing is released against the resilient bias on the reset member and, when disconnecting the detachable member from the housing, the reset member is brought into engagement with the housing by means of the resilient bias on the reset member.

14. Use of a spring in a resettable drug delivery device, the drug delivery device comprising

a housing having a proximal end and a distal end;

a piston rod;

a drive member for rotating the piston rod in a first rotational direction with respect to the housing when setting a dose and for distally displacing the piston rod away from a proximal start position when dispensing the dose;

a stop member for interacting with the piston rod to form an unlockable interlock;

wherein the spring is used

for storing energy for driving a rotation of the piston rod in a second rotational direction, opposite to the first rotational direction, with respect to the housing by interacting with the piston rod for biasing the piston rod in the second rotational direction when setting the dose;

for storing energy for driving a rotation of the stop member in the second rotational direction by interacting with the stop member for biasing the stop member in the second rotational direction when the interlock is locked; and

for transferring force to the stop member for driving a rotation of the stop member in the first rotational direction with respect to the housing and the piston rod by interacting with the stop member for biasing the stop member in the first rotational direction when unlocking the interlock.

15. The use of claim 14, wherein the spring is used for storing energy for driving the rotation of the stop member in the first rotational direction.

16. The use of claim 14, in a drug delivery device further comprising a cartridge and a piston, the piston being retained within the cartridge, wherein the piston rod is configured for distally displacing the piston with respect to the cartridge for dispensing a dose and the spring is additionally used for storing energy for driving an axial displacement for reducing pressure of the piston rod on the piston by interacting with the piston rod for biasing the piston rod in the proximal direction after dispensing of the dose.

17. The use of claim 16 in a drug delivery device further comprising a cartridge holder, wherein the spring is additionally used for resiliently biasing the cartridge in an axial direction when the drug delivery device is in the drive mode for axially and/or rotationally securing the cartridge within the cartridge holder when the drug delivery device is in the drive mode.

18. The use of claim 14 in a drug delivery device further comprising a reset member being releasably engageable with the housing, wherein the spring is additionally used for resiliently biasing the reset member in an axial direction for locking the reset member in engagement with the housing for retaining the drive assembly in the reset mode.