US Patent 11071832 Medicament injection device

An injection device comprising: a housing arranged to contain a medicament cartridge; a needle holder holding an injection needle; a generally tubular needle sleeve fixed with respect to the needle holder and axially movable with respect to the housing; and a gear assembly comprising a rotary gear fixed to the needle holder, a first gear rack disposed on the needle sleeve and a second gear rack disposed on the housing, wherein the gear assembly is arranged so that movement of the needle sleeve in a proximal axial direction causes movement of the needle holder in the proximal axial direction.