Breath actuated dry powder inhaler and tape dose strip

1. A dry powder inhaler comprising:

a housing having an airflow path leading from an inlet, past a powder release location, to a mouthpiece;

a drive spool engaged with a capstan adjacent to the powder release location;

a spring biasing a ratchet into engagement with the drive spool;

a breath trigger in the airflow path, with the breath trigger moveable from a first position, wherein the breath trigger holds the ratchet, to a second position, wherein the breath trigger releases the ratchet to allow the ratchet to turn the drive spool, and

a blister strip supporting a plurality of sealed blisters, each containing a dose of powder, said blister strip being engaged with the drive spool,

wherein one blister is opened each time the breath trigger is moved to the second position.

2. A dry inhaler according to claim 1 , wherein the breath trigger comprises a breath flap assembly pivotably mounted on said housing.

3. A dry inhaler according to claim 2 , wherein the ratchet comprises a trigger arm co-operating with said breath flap assembly, such that inhalation through the mouthpiece causes the breath flap assembly to pivot, which moves said trigger arm, allowing said ratchet to turn the drive spool.

4. A dry powder inhaler comprising:

a housing having an airflow path from an inlet, past a powder release location, to a mouthpiece;

a capstan comprising a first gear;

a drive spool comprising a second gear meshing with the first gear and located to receive between the first and second gears a tape having individually sealed blisters, each blister comprising a dose of powder;

a ratchet engaged with the drive spool, the ratchet advancing the drive spool in at least one rotational direction upon rotation of the ratchet;

a spring that, when tensioned, biases the ratchet in a direction that advances the drive spool;

a trigger comprising a rotatable flap in the airflow path, wherein the trigger is engaged with the ratchet to prevent movement of the ratchet until the trigger is actuated, and wherein the trigger is actuated by applying suction to the mouthpiece to cause air within the airflow path to force rotation of the flap.

5. The dry powder inhaler according to claim 4 , further comprising a dustcap that covers the mouthpiece when the dustcap is closed, and wherein opening or closing the dustcap tensions the spring.