Dose sensing mechanism in a medication delivery device

A method of determining the amount of a dose set and the amount of a dose delivered by operation of a medication delivery device, the device having a housing, a dose dial movable in a spiral manner relative to the housing during dose setting from a start setting axial position to an end setting axial position, the dose dial further being translatable, without rotation, relative to the housing during dose delivery from a start delivery axial position to an end delivery axial position, a barrel rotationally coupled with the dose dial and thereby rotating with the dose dial during dose setting, the barrel being rotatable relative to the housing during dose setting from a start setting angular position to an end setting angular position, and a drive sleeve rotatable relative to the housing during dose delivery from a start delivery angular position to an end delivery angular position, the method comprising:

• setting a dose by moving the dose dial from the start setting axial position to the end setting axial position, thereby also moving the barrel from the start setting angular position to the end setting angular position;
• detecting the start and end setting axial positions of the dose dial during dose setting;
• detecting the start and end setting angular positions of the barrel during dose setting;
• determining the amount of the dose setting using the start and end setting axial positions of the dose dial and the start and end setting angular positions of the barrel;
• delivering a dose by moving the dose dial from the start delivery axial position to the end delivery axial position, thereby also moving the drive sleeve from the start delivery angular position to the end delivery angular position;
• detecting the start and end delivery axial positions of the dose dial during dose delivery;
• detecting the start and end delivery angular positions of the drive sleeve during dose delivery;
• and
• determining the amount of the dose delivery using the start and end delivery axial positions of the dose dial and the start and end delivery angular positions of the drive sleeve.

A medication delivery device, comprising:

• a housing;
• a dose dial having a dose configuration and a delivery configuration, in the dose configuration, the dose dial is movable in a spiral manner relative to said housing between axial positions, and in the delivery configuration, the dose dial is translatable between delivery axial positions;
• a barrel coupled around the dose dial in a manner for rotation with the dose dial in the dose configuration and rotationally fixed for translatable contact with the dose dial in the delivery configuration;
• a drive sleeve coupled within the dose dial in a manner for rotation with dose dial in the delivery configuration from a start delivery angular position to an end delivery angular position;
• an axial sensor system comprising a first sensing component axially coupled with one of the housing and the barrel and a second sensing component axially coupled with the dose dial, the first and second sensing components of the axial sensor system being cooperatively configured to detect and provide outputs indicative of the axial positions of the dose dial in the dose configuration and outputs indicative of the delivery axial positions of the dose dial in the delivery configuration;
• a drive sleeve sensor system comprising a first sensing component coupled with the housing and a second sensing component coupled with the drive sleeve, the first and second sensing components of the drive sleeve sensor system being cooperatively configured to detect and provide outputs indicative of the start delivery angular position and the end delivery angular position;
• and
• a controller operably connected to the axial and drive sleeve sensor systems, and, from the outputs received, configured to determine the amount of dose delivered by the dose dial when in the delivery configuration.