CA2839044C — Dose counter for a metered-dose inhaler

USPTO Abstract

Disclosed herein is a dose counter for counting doses of medicament dispensed by or remaining in a metered-dose inhaler. The dose counter comprises a rotatably mounted first gear wheel having a circular arrangement of ratchet teeth and a display coupled to the first gear wheel, the display having a visible array of dose counting indicia indexable in response to rotary motion of the first gear wheel. The dose counter further comprises an actuator mechanism having a first ratchet drive pawl for engaging the ratchet teeth of the first gear wheel in response to the dispensation of a medicament dose, and a second ratchet drive pawl for engaging the ratchet teeth of a gear wheel coupled to the display. The actuator mechanism is configured such that, in use of the dose counter for counting a dispensed dose, a first ratchet tooth of the first gear wheel is engaged and rotatably driven by the first ratchet drive pawl and then a second ratchet tooth of the gear wheel coupled to the display is engaged and rotatably driven by the second ratchet drive pawl.