FIELD: medicine.
SUBSTANCE: invention refers to medical equipment, namely to drug delivery devices, more particularly to drug delivery devices such as drug delivery devices in the form of an injection pen, such devices promote an unassisted administration of a drug preparation from a cartridge with several doses and provides an option of establishing the dose to be delivered. A dose establishing mechanism for the drug delivery device, preferentially for the drug delivery device in the form of the injection pen with the drug cartridge. The dose establishing mechanism can be used to select the drug dose to be administered from the cartridge. The dose establishing mechanism comprises a handle, a spiral flute, a wrench element on the spiral flute of the handle, and a means preventing the user of the dose establishing mechanism from selecting a drug dose exceeding a drug amount left in the cartridge. The spiral flute has the first pitch provided along the first portion of the handle. When establishing the dose for the drug delivery device, the handle rotates around the wrench element. The wrench element travels longitudinally along the above spiral flute from the first end of the handle towards the second end of the handle. The above device comprises the second pitch provided along the second portion of the handle. The first pitch is different from the above second one. Preferentially, the second pitch exceeds the first one. What is also provided is the third pitch along the third portion of the handle. The first pitch provided along the first portion of the handle is preferentially substantially equal to the above third pitch.
EFFECT: invention prevents from establishing the dose exceeding the drug amount left in the cartridge, thereby eliminating a risk of applying high rotational force when establishing the dose.
14 cl, 11 dwg
