DRUG DELIVERY DEVICE

摘要

A mechanism in the body is used to drive a piston rod and comprises means for guiding the movement of the piston rod relatively to the body while delivering the drug. Further means are provided for releasing the piston rod from the means for guiding the movement, thus enabling a reset of the piston rod to a start position, especially after the receptacle has been emptied and is to be refilled. The device is constructed in such a manner that a reset of the piston rod is facilitated.

主权项

1. A drug delivery device, comprising:
a two-part housing comprising a distal part and a proximal part, where the distal part is removable from the proximal part and is configured as a receptacle to hold a removable cartridge containing a drug; a piston rod operatively located in the proximal part and having a weight associated therewith, the piston rod being movable relative to the housing through axial movement of an operation button in a distal direction to cause a portion of the drug to expel out of the cartridge when the piston rod moves in the distal direction, where the piston rod has a start position with respect to the proximal part prior to expulsion of a first portion the drug from the cartridge; a reset mechanism located in a distal end of the proximal part, the reset mechanism comprising,
a reset nut;a lock nut;a spring; anda piston rod nut, wherein the reset nut guides the movement of the piston rod distally relative to the housing each time a portion of the drug is expelled from the cartridge until an end positioned of the piston rod is reached, where the reset nut is fixed axially relative to the body during the expulsion of the drug, wherein the resetting of piston rod proximally back to the start position is caused by the orientating the body such that the weight of the piston rod in combination with gravity causes the piston rod to retract into the body to the start position.