Drive Mechanism for a Drug Delivery Device and Drug Delivery Device

• US 20130310761A1
• Filed: 10/05/2011
• Published: 11/21/2013
• Est. Priority Date: 10/06/2010
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Inventors: Plumptre, David Aubrey
• Granted Patent: US 9,440,029 B2
• Time in Patent Office: Days
• US Class Current: 604/211
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 5/31515 Connection of piston with piston rod
• CPC Class Codes: A61M 5/3155 by rotational movement of dose setting member, e.g. during setting or filling of a syringe
• 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 5/3156 using volume steps only adjustable in discrete intervals, i.e. individually distinct intervals
• CPC Class Codes: A61M 5/31585 performed by axially moving actuator, e.g. an injection button
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

The drive mechanism comprises a lead screw (5) and a lead screw nut, which are aligned with an axis (4). The lead screw has screw threads (6, 16) having the same pitch and being intertwined.

Claims

1. A drive mechanism for a drug delivery device, comprising:

a lead screw and a lead screw nut aligned with an axis defining an axial direction and an opposite axial direction,

a screw thread and at least one further screw thread of the lead screw, the screw thread and the further screw thread having the same pitch and being intertwined, and

a drive feature of the lead screw nut,

the drive feature engaging the screw thread and the further screw thread and allowing for a dispense operation a helical movement of the lead screw with respect to the lead screw nut at least in the axial direction.

2. The drive mechanism according to claim 1, further comprising:

the axis further defining radial directions diverging from the axis,

the screw thread and the further screw thread of the lead screw having surfaces,

the drive feature engaging the screw thread between the surfaces, and

the surfaces of the screw thread forming a non-zero angle in the radial directions.

3. The drive mechanism according to claim 1, further comprising:

a drive member rotationally locked with the lead screw nut,

the lead screw being coupled with the drive member, the coupling generating a helical movement of the lead screw with respect to the drive member when the drive member is moved in the axial direction with respect to the lead screw, and the coupling being overridden to prevent a helical movement of the lead screw with respect to the drive member when the drive member is moved in the opposite axial direction with respect to the lead screw.

4. The drive mechanism according to claim 3, further comprising:

a flexible guide feature of the lead screw, and

a screw thread of the drive member,

the flexible guide feature of the lead screw and the screw thread of the drive member providing the coupling of the lead screw with the drive member.

5. The drive mechanism according to claim 4, wherein the screw thread of the drive member has two separate co-axial helical features.

6. The drive mechanism according to claim 3, further comprising:

stop features of the lead screw, the stop features inhibiting the helical movement of the lead screw when the drive member is moved in the opposite axial direction with respect to the lead screw.

7. The drive mechanism according to claim 1, wherein the drive feature of the lead screw nut comprises at least two separate parts protruding from an inner surface of the lead screw nut.

8. The drive mechanism according to claim 1, wherein the drive feature of the lead screw nut is tapered towards the screw thread of the lead screw.

9. A drug delivery device, comprising:

a drive mechanism according to claim 1, and

a body having a distal end and a proximal end, which are spaced apart in the direction of the axis.