Drive Mechanism for a Drug Delivery Device and Resilient Element for a Drive Mechanism

• US 20120283651A1
• 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, Bilton, Simon Lewis, Jones, Christopher, Kouyoumjian, Garen, MacDonald, Catherine Anne
• Granted Patent: US 9,446,202 B2
• Time in Patent Office: Days
• US Class Current: 604/210
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 5/31535 Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
• 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 5/3156 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
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

A plunger (4) having engaging means and a lever (5) are arranged in a body (1). The lever has a first pivot that is stationary with respect to the body in the direction of an axis, a second pivot, and a third pivot formed by an engaging element of the lever. The pivots are arranged in such a manner that a rotation of the lever with respect to the first pivot moves the second pivot and the third pivot in the same direction with respect to the axis. The engaging element and the engaging means are shaped such that the lever is disengaged from the plunger when the second pivot is moved relatively to the plunger in the proximal direction (30), and the plunger is engaged with the lever when the second pivot is moved in the distal direction (20).

Claims

1. Drive mechanism for a drug delivery device, comprising:

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

a plunger arranged within the body, the plunger having engaging means,

a lever arranged within the body, the lever having a first pivot that is stationary with respect to the body in the direction of the axis, a second pivot, and a third pivot formed by an engaging element of the lever,

the pivots being arranged in such a manner that a rotation of the lever with respect to the first pivot moves the second pivot and the third pivot in the same direction with respect to the axis,

the engaging element and the engaging means being shaped in such a manner that the lever is disengaged from the plunger when the second pivot is moved relatively to the plunger in the proximal direction, and the plunger is engaged with the lever when the second pivot is moved in the distal direction, and

further engaging means on the plunger,

characterized in that

a resilient element acts on the lever and tends to engage the engaging element with the engaging means, and

the resilient element engages with the further engaging means, thus preventing the plunger from moving in the proximal direction, and

the resilient element disengages from the further engaging means when the plunger is moved in the distal direction.

2. The drive mechanism according to claim 1, wherein the resilient element is engaged with the further engaging means when the second pivot is moved in the proximal direction.

3. The drive mechanism according to claim 1, wherein a movement of the second pivot relatively to the plunger in the proximal direction, the movement disengaging the lever from the plunger, causes a deformation of the resilient element, and a force engaging the resilient element with the further engaging means is enhanced by the deformation.

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

a resilient element exerting a force on the plunger relatively to the body in the proximal direction.

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

the pivots permitting a shift of the lever with respect to the body in a direction transverse to the direction of the axis, the lever being disengaged from the plunger by the shift,

a release block arranged at a provided location within the body, where the release block prevents the shift of the lever, and

the release block being removable from the provided location to enable the lever to be reversibly disengaged from the plunger by the shift.

6. The drive mechanism according to claim 5, wherein the shift of the lever enables a movement of the plunger relatively to the body in the proximal direction.

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

a resilient element exerting a force on the plunger relatively to the body in the proximal direction, the resilient element resetting the plunger to a start position when the lever is permanently disengaged from the plunger by the shift.

8. The drive mechanism according to claim 5, further comprising:

a removable and attachable part removable from and attachable to the body at the distal end, and a resilient element acting on the release block, the release block being kept removed from the provided location by means of the resilient element when the removable and attachable part is not attached to the body.

9. The drive mechanism according to claim 8, wherein the removable and attachable part of the body is a cartridge holder, and the release block is held in the provided location when the removable and attachable part is attached to the body with a cartridge inserted.

10. The drive mechanism according to claim 8, wherein a resilient element which acts on the lever and tends to engage the engaging element with the engaging means, and the resilient element which acts on the release block are a spring member formed from a wire.

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

a last-dose stop provided on the plunger, the last-dose stop limiting the engaging means in the proximal direction and preventing the engaging element from being moved past the last-dose stop.

12. A use of a resilient element for a drive mechanism according to claim 1, the resilient element comprising:

a resilient or resiliently mounted cantilever with a hook having a sloping profile, the hook being formed in such a fashion that a sawtooth structure that is arranged parallel to the cantilever and moved relatively to the cantilever is either arrested by means of the hook engaging a sawtooth or, depending on the direction of the relative movement, deflects the cantilever by means of the sloping profile sliding over a sawtooth, and a section of the cantilever being provided for a lever to act on, the cantilever being deflected by a shift of the lever in a direction transverse to the cantilever.

13. The use of a resilient element according to claim 12, further comprising:

a further resilient or resiliently mounted cantilever, the cantilevers having a common mounting, and the cantilevers extending into directions that are transverse to one another.

14. The use of a resilient element according to claim 13, further comprising:

the cantilever and the further cantilever being parts of a spring formed from a wire.