Dry powder inhaler dose counters
Dry powder inhaler dose counters capable of making a display move swiftly between digits, in contrast to the progressive movement that occurs in simple gearing mechanisms.
1. A dry powder inhalation device comprising:
a housing defining a chamber;
a patient port in communication with said chamber;
an elongate carrier carrying medicament;
an advancement mechanism for advancing a length of the elongate carrier into the chamber;
a displacement sensor that advances in association with continuous advancement of the elongate carrier; and
a transfer component that converts the advancement of the displacement sensor into intermittent motion of a units dose display;
wherein the displacement sensor has a range of movably engaged positions wherein the displacement sensor movably engages the transfer component, and
the dry powder inhalation device further comprises a discrete alignment mechanism capable of moving the displacement sensor backwards to one of a plurality of spatially defined positions that are not within said range of movably engaged positions.
2. A dry powder inhalation device according to claim 1 , further comprising a cover configured to cover the patient port when in a first position, wherein the cover is in mechanical communication with the advancement mechanism such that removing the cover from the patient port advances the advancement mechanism.
3. A dry powder inhalation device according to claim 2 wherein the discrete alignment mechanism comprises a reverse pawl wheel capable of engaging with a post fixed to the device housing.
4. A dry powder inhalation device according to claim 3 wherein the reverse pawl wheel comprises two pawl arms.
5. A dry powder inhalation device according to claim 4 wherein the discrete alignment mechanism comprises a slot in the reverse pawl wheel that is reversibly engageable with a post fixed to the device housing.
6. A dry powder inhalation device according to claim 1 wherein the advancement mechanism comprises a rotatable mouthpiece cover.
7. A dry powder inhalation device according to claim 1 wherein the advancement mechanism comprises an uptake spool.
8. A dry powder inhalation device according to claim 7 wherein the displacement sensor is driven by gears on the uptake spool.
9. A dry powder inhalation device according to claim 1 wherein the displacement sensor comprises a rotatable gear.
10. A dry powder inhalation device according to claim 1 wherein the transfer component comprises a Geneva wheel.
11. A dry powder inhalation device according to claim 10 wherein the Geneva wheel has scallops along its outer edge.
12. A dry powder inhalation device according to claim 1 wherein the units dose display is a geared units dose wheel with numerical indicia on one face of the wheel.
13. A dry powder inhalation device according to claim 12 further comprising a tens dose display comprising a geared tens dose wheel coupled to the units dose wheel and wherein the units dose display and the tens dose display cooperate to indicate a number of doses remaining in the device.
14. A dry powder inhalation device according to claim 13 wherein the tens dose wheel has scallops along its outer edge.
15. A dry powder inhalation device according to claim 1 wherein the elongate carrier is a dimpled tape.
16. A dry powder inhalation device according to claim 1 wherein the displacement sensor moves in association with movement of the elongate carrier.