Drive mechanism for a drug delivery device

Abstract

The present invention relates to a drive mechanism for a drug delivery device as well as to a drug delivery device for dispensing of a dose of a medicinal product, wherein the drive mechanism comprises:a holder for a product-containing cartridge, the cartridge having a piston slidably arranged therein in an axial direction,a piston rod to be operably engaged with the cartridge's piston for dispensing of a dose of the medicinal product,at least one adjusting member slidably arranged in axial direction relative to the piston and / or relative to the piston rod for eliminating axial clearance between the piston and the piston rod,an interlock means adapted to interact with the adjusting member for mutually locking in position the piston and the piston rod irrespective of the relative distance between piston and piston rod.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application is a U.S. National Phase Application pursuant to 35 U.S.C. §371 of International Application No. PCT / EP2010 / 055140 filed Apr. 20, 2010, which claims priority to _European Patent Application No. 09005996.5 filed on Apr. 30, 2009. The entire disclosure contents of these applications are herewith incorporated by reference into the present application.FIELD OF THE INVENTION[0002]This invention relates to a drive mechanism for a drug delivery device that allows a user to select single or multiple doses of an injectable medicinal product and to dispense the set dosage of the product and to apply said product to a patient, preferably by injection. In particular, the present invention relates to such devices, which are handled by the patients themselves.BACKGROUND[0003]Drug delivery devices allowing for multiple dosing of a required dosage of a liquid medicinal product, such as liquid drugs, and further providing administr...

AI Technical Summary

Benefits of technology

[0013]It is therefore an object of the present invention to provide a drive mechanism for a drug delivery device featuring improved and facilitated clearance and manufacturing tolerance elimination. It is a further object of the invention to redundantize a priming procedure to be conducted by the end user. The invention further focuses on improvements related to patient safety and intends to simplify the general device handling. It is a further object of the invention, to provide a drive mechanism for a drug delivery device with clearance eliminating means being inexpensive to produce and being easy to assemble. Finally, it is an object of the invention to provide a method of eliminating clearance in a drive mechanism of a drug delivery device.SUMMARY

Problems solved by technology

For instance in case of those with diabetes, many users will be physically infirm and may also have impaired vision.

Since the generation of an electromagnetic field requires a supply of electric energy, such a solution is generally not applicable to drug delivery devices of pen-injector type.

These known solutions feature the common drawback, that for elimination of axial clearance between piston rod and piston, the piston rod has to be axially shifted.

Such axial displacement of the piston rod for the purpose of clearance elimination is regarded as disadvantageous, because it typically involves a respective actuation of dose setting or dose dispensing means by the user.

Images