Dose indicator for a metered dose inhaler
The present disclosure relates to a dose indicator comprising, a chassis comprising a chassis frame and a displacement portion, an indexable first display unit, mountable on the chassis, the first display unit being indexable about a first display axis, the indexable first display unit comprising a plurality of indexing teeth, a first display non-return arm, and a drive pawl connected at its proximal part to the displacement portion, the drive pawl comprising a socket at its distal part, the socket being adapted to engage an indexing tooth of the first display unit during indexing. The disclosure further relates to an actuator for an inhaler, wherein the actuator comprises a dose indicator as described above. The present disclosure is also directed to an inhaler comprising such actuator.
1. A dose indicator comprising,
a chassis comprising a chassis frame and a displacement portion,
an indexable first display unit, mountable on the chassis, the first display unit being indexable about a first display axis, the indexable first display unit comprising a plurality of indexing teeth,
a first display non-return arm, and
a drive pawl connected at its proximal part to the displacement portion, the drive pawl comprising:
a socket formed in its distal part, the socket being adapted to partially surround and engage a first indexing tooth of the first display unit during indexing, and
an outer surface connecting the proximal part and the distal part, the outer surface adapted to contact a second indexing tooth during resetting of the pawl after indexing.
2. The dose indicator as claimed in claim 1 , wherein the distal part of the drive pawl comprises jaws, the inner surfaces of which define the socket.
3. The dose indicator as claimed in claim 1 , wherein the drive pawl is resiliently displaceable by a displacement force from the subsequent indexing tooth during resetting of the pawl after indexing.
4. The dose indicator as claimed in claim 3 , wherein the drive pawl and indexing teeth are adapted so that the displacement force is applied at a small displacement angle during resetting.
5. The dose indicator as claimed in claim 1 , wherein the chassis further comprises at least one return mechanism.
6. The dose indicator as claimed in claim 5 , wherein the return mechanism comprises at least one spring.
7. The dose indicator as claimed in claim 6 , wherein the at least one spring comprises a leaf spring.
8. The dose indicator as claimed in claim 7 , wherein the leaf spring comprises a curved leaf spring.
9. The dose indicator as claimed in claim 1 , wherein each indexing tooth comprises a pawl engagement portion adapted to engage the socket.
10. The dose indicator as claimed in claim 1 , wherein the non-return arm and the drive pawl both engage the same set of indexing teeth.
11. The dose indicator as claimed in claim 1 , further comprising an indexable second display unit indexable about a second display axis, the second display axis being transverse to the first display axis.
12. The dose indicator as claimed in claim 11 , wherein the first display unit and/or the second display unit are substantially circular and are rotatably indexable about the first display axis and/or about the second display axis respectively.
13. The dose indicator as claimed in claim 11 , wherein the second display unit is a tens display unit.
14. The dose indicator as claimed in claim 11 , wherein the first display unit comprises a drive arm adapted to index the second display unit.
15. The dose indicator as claimed in claim 11 , wherein the second display unit has a substantially annular cross section.
16. The dose indicator as claimed in claim 1 , wherein the chassis is moulded as a unitary piece.
17. The dose indicator as claimed in claim 1 , wherein the drive pawl is integrally comprised in the displacement portion.
18. The dose indicator as claimed in claim 1 , wherein the displacement portion is adapted to be displaced along a displacement path.
19. The dose indicator as claimed in claim 18 , wherein the displacement path is at least partly transverse to the first display axis.
20. The dose indicator as claimed in claim 18 , wherein the displacement path is at least partly arcuate.
21. The dose indicator as claimed in claim 1 , wherein the displacement portion is mounted to the chassis frame by at least one hinge.
22. The dose indicator as claimed in claim 21 , wherein the proximal part of the drive pawl is located on the displacement portion at a position remote from the at least one hinge at a position of the displacement portion distal to the at least one hinge.
23. The dose indicator as claimed in claim 21 , wherein the at least one return mechanism directly or indirectly connects the displacement portion and chassis frame at a position remote from the at least one hinge.
24. The dose indicator as claimed in claim 1 , wherein the displacement portion comprises at least one press member.
25. The dose indicator as claimed in claim 1 , wherein the first display non-return arm is at least partly located on the chassis frame.
26. The dose indicator as claimed in claim 1 , wherein the first and/or the second display unit is adapted to index through between 5 and 25 indicia.
27. The dose indicator as claimed in claim 26 , wherein the first and/or the second display unit is adapted to index through between 8 to 12 indicia.
28. The dose indicator as claimed in claim 1 , further comprising a first display unit mounting mechanism that mounts the display unit on the chassis frame so that it is indexable about the first display axis.
29. The dose indicator as claimed in claim 1 , wherein the first display unit is a units display unit.
30. The dose indicator as claimed in claim 1 , wherein the first display unit has a substantially circular cross section.
31. The dose indicator as claimed in claim 1 , wherein the first and/or the second display unit comprises a zero stop member.
32. The dose indicator as claimed in claim 31 , wherein the zero stop member interacts with a stop arm located on the chassis.
33. The dose indicator as claimed in claim 1 , wherein the chassis comprises polyoxymethylene.
34. An actuator for an inhaler, the actuator comprising a dose indicator as claimed in claim 1 .
35. An inhaler comprising an actuator as claimed in claim 34 .