Reset mechanism for an inhaler
A valved-container inhaler ( 150 ) has a mechanical return assembly with a spring ( 214 ) and a transfer ( 212 ) configured to transfer stored potential energy from the spring to a canister ( 51 ) and a clutch ( 208, 210 ) in a load path of the force between the spring and the transfer, the clutch being rotatable between a first condition in which load is transferred from the spring to the transfer, and a second condition in which the spring and the transfer can move relative to one another to interrupt the load path and thereby allow the canister to resile after actuation.
1. A mechanical return assembly for a valved-container inhaler comprising:
a resilient structure;
a transfer configured to transfer stored potential energy from the resilient structure to a resilient, valved container in the form of a force to thereby release a medicament therefrom;
a clutch in a load path of the force between the resilient structure and the transfer, the clutch having a first part and a second part, in which rotation of the second part relative to the first part moves the clutch between:
a first condition in which load is transferred from the resilient structure to the transfer, and
a second condition in which the resilient structure and the transfer can move relative to one another to interrupt the load path and disconnect the valved canister from the force and thereby allow the valved container to resile after actuation.
2. The mechanical return assembly for a valved-container inhaler according to claim 1 , in which the rotation of the second part relative to the first part is effected by a linear force applied to a ramped surface.
3. The mechanical return assembly for a valved-container inhaler according to claim 2 , in which the ramped surface is defined on at least the second part to effect the rotation thereof.
4. The mechanical return assembly for a valved-container inhaler according to claim 3 , comprising:
a housing; and,
a static actuator formation fixed with respect to the housing, wherein the static actuator formation is configured to engage the ramped surface of the second part;
in which the linear force is applied from the first part to the second part to rotate the second part by engagement of the ramped surface of the second part with the static actuator formation.
5. The mechanical return assembly for a valved-container inhaler according to claim 4 , in which the clutch is configured to move linearly from:
a first position in which the clutch is in the first condition to a second position in which the clutch is in the first condition to transfer the stored potential energy from the resilient structure to the transfer; and,
the second position to a third position upon engagement of the ramped surface of the second part with the static actuator formation to move the clutch to the second condition.
6. The mechanical return assembly for a valved-container inhaler according to claim 4 , in which the resilient structure comprises a compression spring.
7. The mechanical return assembly for a valved-container inhaler according to claim 3 , in which the second part is capable of linear movement relative to the first part, and the linear force is applied from the first part to the ramped surface on the second part to effect rotation of the second part.
8. The mechanical return assembly for a valved-container inhaler according to claim 7 , in which the first part is rotationally fixed, and rotation of the second part is inhibited for part of the linear movement of the second part.
9. The mechanical return assembly for a valved-container inhaler according to claim 8 , in which the clutch is configured to move linearly through:
a first stage linear movement in which the clutch is in the first condition to transfer the stored potential energy from the resilient structure to the transfer, during which rotation of the second part is inhibited; and,
a second stage linear movement during which rotation of the second part is permitted to thereby move the clutch to the second condition.
10. The mechanical return assembly for a valved-container inhaler according to claim 9 , in which the first part of the clutch and the resilient structure are positioned on opposite sides of the second part of the clutch, in which the first part of the clutch moves into the second part of the clutch when moving from the first to the second condition.
11. The mechanical return assembly for a valved-container inhaler according to claim 10 , in which the first and second parts of the clutch are in sliding engagement.
12. The mechanical return assembly for a valved-container inhaler according to claim 10 , in which the first part of the clutch comprises a first abutment and the second part of the clutch comprises a second abutment, in which in the first condition the first and second abutments are aligned and in contact, and in the second condition the first and second abutments are misaligned.
13. The mechanical return assembly for a valved-container inhaler according to claim 12 , in which the first and/or second abutments comprise a plurality of spaced-apart teeth.
14. The mechanical return assembly for a valved-container inhaler according to claim 13 , in which a damper is provided to damp relative movement between the transfer and the resilient structure upon movement of the clutch to the second condition.
15. The mechanical return assembly for a valved-container inhaler according to claim 14 , in which the resilient structure comprises a tension spring.
16. The mechanical return assembly for a valved-container inhaler according to claim 1 , in which the resilient structure defines a body having an interior space in which to receive the valved container.
17. A valved-container inhaler comprising a mechanical return assembly according to claim 16 , comprising a priming mechanism configured to transfer energy to the resilient structure.
18. The valved-container inhaler according to claim 17 , in which the priming mechanism is user-actuated.
19. The valved-container inhaler according to claim 17 , in which the priming mechanism comprises a linearly displaceable element engaged with part of the resilient structure to apply a linear force thereto.
20. The valved-container inhaler according to claim 19 , comprising a firing mechanism, in which the return assembly has:
a rest condition;
a stable primed condition in which the resilient structure stores potential energy; and
a fired condition in which the resilient structure has been released to transfer force to the transfer, and the clutch is in the second condition;
in which the firing mechanism is configured to release the resilient structure.