Drive mechanism for an injection device

Patent metadata

Field	Value
Publication number	US-10293113-B2
Application number	US-201615548503-A
Country	US
Kind code	B2
Filing date	Feb 10, 2016
Priority date	Feb 10, 2015
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

The present disclosure relates to a drive mechanism for an injection device for setting and dispensing of a dose of a medicament, the drive mechanism comprising:
an inner body fixable inside a housing of the injection device, the inner body comprising an elongated shaft extending in an axial direction (z) and having an outer thread, a tubular-shaped display member having an inner thread engaged with the outer thread of the inner body, and a dose member axially displaceable between a dose setting position (S) and a dose dispensing position (D) relative to the display member, wherein the display member comprises at least one blocking member movable in axial direction (z) between a blocking position (B) and a release position (R) and engageable with a blocking structure on the outer circumference of the inner body, wherein when in blocking position (B) the blocking member axially engages with the dose member and with the blocking structure to block an axial displacement of the dose member from the dose setting position (S) towards the dose dispensing position (D).

First claim

The invention claimed is:

1. A drive mechanism for an injection device for setting and dispensing of a dose of a medicament, the drive mechanism comprising: an inner body fixable inside a housing of the injection device, the inner body comprising an elongated shaft extending in an axial direction and having an outer thread;
a tubular-shaped display member having an inner thread engaged with the outer thread of the inner body; and
a dose member axially displaceable between a dose setting position and a dose dispensing position relative to the display member,
wherein the display member comprises at least one blocking member movable in axial direction between a blocking position and a release position and engageable with a blocking structure on the outer circumference of the inner body,
wherein when in blocking position the blocking member axially engages with the dose member and with the blocking structure to block an axial displacement of the dose member from the dose setting position towards the dose dispensing position.

2. The drive mechanism according to claim 1 , wherein the blocking structure comprises a blocking thread axially extending on the elongated shaft of the inner body, wherein the blocking thread ( 27 ; 227 ) and the outer thread ( 21 ; 221 ) have the same pitch.

3. The drive mechanism according to claim 2 , wherein a distal end of the blocking thread is chamfered.

4. The drive mechanism according to claim 3 , wherein, when rotating the display member in a dose incrementing direction, the protrusion of the blocking member slides along the chamfer of the blocking thread's distal end:
i) to flex the blocking member's free end section from its release position in proximal direction towards its blocking position, or
ii) to axially abut with the blocking thread's proximally facing edge.

5. The drive mechanism according to claim 3 , wherein, when rotating the display member in a dose dispensing direction with the blocking member in release position, the protrusion of the blocking member slides along a distal edge of the blocking thread as the blocking member passes the blocking thread's proximal end when entering the blocking thread.

6. The drive mechanism according to claim 3 , wherein the blocking thread comprises at least one recess having a size to receive the blocking member or its radially inwardly extending protrusion.

7. The drive mechanism according to claim 1 , wherein the blocking member comprises a flexible arm extending in a tangential direction along the circumference of the display member.

8. The drive mechanism according to claim 1 , wherein the blocking member comprises a radially inwardly extending protrusion at a free end section to engage with the blocking structure.

9. The drive mechanism according to claim 1 , wherein the blocking member comprises an abutment at its free end section facing in axial direction to axially abut with a corresponding abutment of the dose member.

10. The drive mechanism according to claim 1 , wherein the axial position of a distal end of the blocking structure on the inner body defines a maximum size of a dose for a priming procedure.

11. The drive mechanism according to claim 1 , wherein the axial position of a proximal end of the blocking structure on the inner body defines a minimum size of a therapeutic dose.

12. The drive mechanism according to claim 1 , wherein the display member comprises a number sleeve and a dial sleeve, and wherein the at least one blocking member is located on the dial sleeve or wherein the at least one blocking member is integrally formed with the dial sleeve.

13. The drive mechanism according to claim 1 , wherein the inner body comprises at least a first maximum dose stop at its outer circumference to engage with first and second radially inwardly extending maximum dose stops of the display member, respectively, when the display member arrives in a maximum dose position.

14. The drive mechanism according to claim 1 , further comprising a piston rod and a tubular-shaped driver extending in axial direction, wherein the piston rod comprises a first outer thread engaged with an inner thread of the inner body and comprises a second outer thread of opposite hand engaged with an inner thread of the driver.

15. The drive mechanism according to claim 14 , wherein the dose member is permanently splined with the driver which is selectively rotationally lockable to the inner body by displacing the dose member into the dose dispensing position and wherein the dose member and the display member are selectively rotationally lockable and releasable via a clutch rotationally engaging the dose member and the display member when the dose member is in dose setting position and rotationally releasing the dose member and the display member when the dose member is in dose dispending position.

16. An injection device for setting and dispensing of a dose of a medicament, comprising: a housing ( 10 ) comprising a drive mechanism for an injection device for setting and dispensing of a dose of a medicament, the drive mechanism comprising:
an inner body fixable inside a housing of the injection device, the inner body comprising an elongated shaft extending in an axial direction and having an outer thread;
a tubular-shaped display member having an inner thread engaged with the outer thread of the inner body; and
a dose member axially displaceable between a dose setting position and a dose dispensing position relative to the display member,
wherein the display member comprises at least one blocking member movable in axial direction between a blocking position and a release position and engageable with a blocking structure on the outer circumference of the inner body,
wherein when in blocking position the blocking member axially engages with the dose member and with the blocking structure to block an axial displacement of the dose member from the dose setting position towards the dose dispensing position; and
a cartridge arranged inside the housing and filled with a liquid medicament.

17. The injection device of claim 16 , wherein the liquid medicament comprises a pharmaceutically active compound.

Assignees

• Sanofi Aventis Deutschland

Inventors

• Plumptre David Aubrey
• Veasey Robert
• Cross John David

Classifications

• A61M5/31541 Primary

  Means preventing setting of a dose beyond the amount remaining in the cartridge · CPC title

• A61M5/31585 Primary

  performed by axially moving actuator, e.g. an injection button · CPC title

• A61M5/31575

  using scaling up or down transmissions, e.g. gearbox · CPC title

• A61M2205/582

  by tactile feedback · CPC title

• A61M2205/581

  by audible feedback · CPC title