Inhaler device with means for assessing its depletion level

Abstract

A balance mechanism incorporates the housing of an aerosol delivery device which accepts and supports a cylindrical medicament cartridge. An unstable balance mechanism produces a definitive toggling action between mechanical states at the specified depletion level at which reliable dosage metering is no longer assured. In one embodiment, a fulcrum structure is formed in one side of an inhaler housing that causes the housing and the cartridge to pivot or rotate about an axis to indicate the depletion of the useful mass of the contents of the cartridge. In this embodiment, the rotation of the housing and cylindrical container is about the pivot axis located at the apex of the fulcrum formed in the housing when the housing is supported on a horizontal surface. The mechanism can also utilize the known mass of an associated mouthpiece cover or other bias weight to modify the balance criterion so as to assess whether the vessel contains a minimum reserve quantity of medicament above and beyond the reliable dosage metering level. A stable balance mechanism may additionally or alternatively be incorporated in the housing of the inhaler for assessing the continuous state of depletion of the aerosol vessel ranging from completely full to completely empty. The stable balance mechanism incorporates a pivoting needle that indicates an analog estimate of the depletion level.