Assembly for a Drug Delivery Device

• US 20120283653A1
• Filed: 09/29/2010
• Published: 11/08/2012
• 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, Jones, Christopher, MacDonald, Catherine Anne, Kouyoumjian, Garen
• Granted Patent: US 9,463,278 B2
• Time in Patent Office: Days
• US Class Current: 604/211
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 2005/2488 via rotation, e.g. threads or bayonet
• CPC Class Codes: A61M 2005/2492 via snap connection
• 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 5/3146 Priming, e.g. purging, reducing backlash or clearance
• 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 5/3156 using volume steps only adjustable in discrete intervals, i.e. individually distinct intervals
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button

Abstract

A resettable drive mechanism for a drug delivery device (1) comprises a piston rod assembly (32) and an interaction member (23). The piston rod assembly (32) comprises a guide track (18) running along the piston rod assembly (32), the guide track (18) comprising at least one delivery section (18A) and at least one reset section (18B). The reset section (18B) is arranged to continue the delivery section (18A). The delivery section (18A) comprises at least one blocking means (19). The interaction member (23) is configured to cooperate with the guide track (18). For delivering a dose of a drug (24), the piston rod assembly (32) is axially displaceable in a dose delivery direction away from an axial starting position, the interaction member (23) cooperating with the delivery section (18A) and the blocking means (19) passing the interaction member (23) when the piston rod assembly (32) is displaced in the dose delivery direction. Axial displacement of the piston rod assembly (32) towards the axial starting position is prevented by mechanical interaction of the blocking means (19) and the interaction member (23) when the interaction member (23) cooperates with the delivery section (18A). For resetting the drug delivery device (1), the interaction member (23) is configured to cooperate with the reset section (18B), the piston rod assembly (32) being axially displaced towards the axial starting position, the blocking means (19) being offset from the interaction member (23) and passing the axial position of the interaction member (23) when the piston rod assembly (32) is axially displaced towards the axial starting position. Also, a piston rod assembly (32) is proposed.

Claims

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

a piston rod assembly, the piston rod assembly comprising a guide track running along the piston rod assembly, the guide track comprising at least one delivery section and at least one reset section, the reset section being arranged to continue the delivery section, the delivery section comprising at least one blocking means, and

an interaction member, the interaction member being configured to cooperate with the guide track,

wherein, for delivering a dose of a drug, the piston rod assembly is axially displaceable in a dose delivery direction away from an axial starting position, the interaction member cooperating with the delivery section and the blocking means passing the interaction member when the piston rod assembly is displaced in the dose delivery direction, axial displacement of the piston rod assembly towards the axial starting position being prevented by mechanical interaction of the blocking means and the interaction member when the interaction member cooperates with the delivery section, and wherein, for resetting the drug delivery device, the interaction member is configured to cooperate with the reset section, the piston rod assembly being axially displaced towards the axial starting position, the blocking means being offset from the interaction member and passing the axial position of the interaction member when the piston rod assembly is axially displaced towards the axial starting position.

2. The resettable drive mechanism of claim 1, wherein the reset section is arranged to form a continuous circuit with the delivery section.

3. The resettable drive mechanism of claim 1, wherein, when the interaction member cooperates with the reset section, the blocking means is angularly offset from the interaction member.

4. The resettable drive mechanism according to claim 1, wherein the reset section extends axially along the delivery section.

5. The resettable drive mechanism according to claim 1, wherein the reset section is angularly offset with respect to the delivery section and the angular offset between reset section and delivery section decreases in the axial direction away from the axial starting position.

6. The resettable drive mechanism according to claim 1, wherein the delivery section is connected to the reset section via an angularly extending connection region of the guide track.

7. The resettable drive mechanism of claim 6, wherein, for resetting the drive mechanism, the piston rod assembly is rotatable such that the connection region passes the interaction member and the interaction member is put into mechanical cooperation with the reset section.

8. The resettable drive mechanism of claim 6, wherein a transition from the delivery section into the reset section is blocked, aside from via the connection region.

9. The resettable drive mechanism according to claim 7, wherein a section separator is arranged in the connection region, the section separator blocking rotation of the piston rod assembly in that direction which would put the interaction member back into interaction with the delivery section via the connection region.

10. The resettable drive mechanism according to claim 1, wherein the delivery section extends obliquely with respect to the main longitudinal axis of the piston rod assembly and the reset section extends less obliquely with respect to the main longitudinal axis of the piston rod assembly than the delivery section.

11. The resettable drive mechanism according to claim 1, wherein the delivery section and the interaction member define a rotation angle by which the piston rod assembly is rotated by mechanical interaction of the interaction member and the delivery section when the piston rod assembly is axially displaced for delivering a dose.

12. The resettable drive mechanism according to claim 1, wherein, when the piston rod assembly has been moved back into the axial starting position, the piston rod assembly is rotatable to put the interaction member in mechanical cooperation with the delivery section or an other delivery section.

13. The resettable drive mechanism according to claim 1, wherein the drive mechanism comprises a drive member, the drive member being configured to drive the axial displacement of the piston rod assembly in the dose delivery direction by mechanical interaction of an interaction surface of the piston rod assembly with a drive feature of the drive member, and wherein, for resetting the drug delivery device, the piston rod assembly is configured to be rotatable such that the interaction surface is angularly displaced with respect to the drive feature such that the interaction surface may pass the axial position of the drive feature with an angular offset.

14. The resettable drive mechanism according to claim 1, wherein the delivery section comprises a plurality of dose sections with two adjacent dose sections being separated by the blocking means.

15. The resettable drive mechanism according to claim 13, wherein the guide track is provided at an outer surface of the piston rod assembly and the interaction surface is provided at an inner surface of the piston rod assembly.

16. The resettable drive mechanism according to claim 1, wherein the delivery section extends in the angular direction by less than 360 degree over its total axial extension.

17. A piston rod assembly for a drug delivery device, the piston rod assembly comprising a continuous guide track running along the piston rod assembly the guide track comprising at least one first section and at least one second section, the first section comprising at least one first blocking means suitable to provide a uni-directional coupling along the first section, the first section extending obliquely with respect to the main longitudinal axis of the piston rod assembly, wherein the second section is angularly offset and angularly separated from the blocking means and extends axially past the blocking means.