Patent ID: 8790315
Filing Date: 2014-07-29
Classification: A61M

Abstract:
1. A dose setting mechanism for a drug delivery device, with a cartridge of medication, wherein the dose setting mechanism is operable to select a dose of medication which shall be administered out of said cartridge, the dose setting mechanism comprising: a shaft comprising a helical thread having three separate portions, a first portion having a first pitch followed by a second portion having a second pitch that is larger than the first pitch and a third portion following the second portion having a third pitch that is less than the second pitch; a nut member disposed on said helical thread of said shaft, wherein during dose setting of said drug delivery device, said shaft is rotated relative to said nut member while said nut member traverses in longitudinal direction along said helical thread from a first end of said shaft towards a second end of said shaft; where the nut member and shaft are configured to engage each other to form a stop mechanism to prevent a user of said dose setting mechanism from setting a dose of said medication that is greater than said remaining medication in said cartridge, the stop mechanism further comprising a radial stop face on the nut member, and a counter radial stop face on the shaft configured to engage the radial stop face on the nut member to prevent the shaft from rotating relative to the nut member.