Needle shield mechanism and a medicament delivery device comprising the needle shield mechanism

1. A needle shield mechanism for an auto-injector, which needle shield mechanism comprises,

a longitudinally elongated, generally tubular housing having a ledge on an inner surface, a forward end and a rear end,

a generally tubular needle shield movably arranged in the housing between a retracted state and an extended position,

a releasable spring-biased container carrier assembly for accommodating a medicament container,

wherein the container carrier assembly is movably arranged in the housing and is movable relative to the housing from an initial position to a penetrating position, and is also movable relative to the needle shield,

wherein the container carrier assembly prevents the needle shield from moving to the extended position when the container carrier assembly is in the initial position, and

wherein the container carrier assembly allows the needle shield to move to the extended position when the container carrier assembly is in the penetrating position, and

wherein the needle shield is spring-biased and comprises a deflectable locking element, which deflectable locking element comprises an outwardly directed protrusion that is radially deflectable and interacts with the ledge when the needle shield is in the retracted state, and

wherein the container carrier assembly prevents the deflectable locking element from deflecting radially when the container carrier assembly is in the initial position and the needle shield is in the retracted state.

2. The needle shield mechanism for an auto-injector according to claim 1 , wherein the container carrier assembly comprises a container carrier, configured to

accommodate a medicament container.

3. The needle shield mechanism for an auto-injector according to claim 2 , wherein the container carrier assembly further comprises an intermediate drive member fixedly connected to the container carrier.

4. The needle shield mechanism for an auto-injector according to claim 3 , wherein either the container carrier or the intermediate drive member is adjacent and radially inside the deflectable locking element of the needle shield when the container carrier assembly is in the initial position and the needle shield is in the retracted state, thereby preventing the deflectable locking element from deflecting radially inwards.

5. The needle shield mechanism for an auto-injector according to claim 3 , wherein either the container carrier or the intermediate drive member is in front of, and radially inside, the deflectable locking element of the needle shield when the container carrier assembly is in the penetrating position and the needle shield is in the retracted state, thereby allowing the deflectable locking element to deflect radially inwards, and allowing the needle shield to move to the extended position.

6. The needle shield mechanism or an auto-injector according to claim 5 , wherein either the container carrier or the intermediate drive member is adjacently and radially inside the deflectable locking element of the needle shield when the container carrier assembly is in the penetrating position and the needle shield is in the extended position, thereby preventing the deflectable locking element from deflecting radially inwards.

7. The needle shield mechanism for an auto-injector according to claim 3 , further comprising an injection mechanism comprising at least one flexible element arranged on the intermediate drive member.

8. The needle shield mechanism for an auto-injector according to claim 7 , wherein the at least one flexible element is arranged with an inwardly directed ledge.

9. The needle shield mechanism for an auto-injector according to claim 8 , further comprising a plunger having a recess, in which the inwardly directed ledge of the intermediate drive member is positioned when the container carrier assembly in the initial position.

10. The needle shield mechanism for an auto-injector according to claim 7 , wherein the recess comprises a circumferential groove.

11. The needle shield mechanism for an auto-injector according to claim 1 , wherein the outwardly directed protrusion comprises a chamfered surface which interacts with the ledge of the inner surface of the housing.

12. The needle shield mechanism for an auto-injector according to claim 1 , wherein the needle shield comprises a locking member and the housing comprises a corresponding locking member.

13. The needle shield mechanism for an auto-injector according to claim 12 , wherein the locking member and the corresponding locking member engage each other when the needle shield is in the extended position to lock the needle shield in the extended position.

14. The needle shield mechanism for an auto-injector according to claim 1 , wherein the outwardly directed protrusion of the deflectable locking element interacts with a forward ledge of an inner surface of the housing when the needle shield is in the extended position.

15. The needle shield mechanism for an auto-injector according to claim 1 , wherein the needle shield in the retracted state is movable between a partially extended position and a triggering position.

16. The needle shield mechanism for an auto-injector according to claim 15 , wherein the container carrier assembly is configured to be released to move to the penetrating position when the needle shield is in the triggering position.

17. A needle shield mechanism for an auto-injector, which needle shield mechanism comprises,

a longitudinally elongated, generally tubular housing having a forward end and a rear end,

a generally tubular needle shield movably arranged in the housing between a retracted state and an extended position,

a releasable spring-biased container carrier assembly for accommodating a medicament container,

wherein the container carrier assembly is movably arranged in the housing and is movable relative to the housing from an initial position to a penetrating position, and is also movable relative to the needle shield,

wherein the container carrier assembly prevents the needle shield from moving to the extended position when the container carrier assembly is in the initial position, and

wherein the container carrier assembly allows the needle shield to move to the extended position when the container carrier assembly is in the penetrating position, and

wherein the needle shield is spring-biased and comprises a deflectable locking element, which deflectable locking element is radially deflectable, and

wherein a component of the container carrier assembly, either a container carrier or an intermediate drive member, is adjacent and radially inside the deflectable locking element of the needle shield when the container carrier assembly is in the initial position and the needle shield is in the retracted state, thereby preventing the deflectable locking element from deflecting radially inwards.