Patent ID: 8628499
Filing Date: 2014-01-14
Classification: A61M

Abstract:
1. Injection device comprising at least: a body designed to receive a product to be injected, said body being provided at its distal end with an injection needle, said body receiving a piston rod and a piston capable of moving in said body between a storage position and an end-of-injection position and of pushing said product through said injection needle, a sleeve for covering said injection needle, said sleeve being movable relative to said body between at least an initial position, in which said injection needle is uncovered, and a final position, in which said injection needle is at least partially covered, and a spring arranged to move said sleeve between said initial and final positions, wherein, said piston rod comprises at least a first portion and a second portion, said first portion and said second portion being axially connected to each other and able to switch between at least a locked position, in which said first portion and said second portion are fixed with respect to each other along the longitudinal axis of said piston rod, and an unlocked position, in which said first portion and said second portion are allowed to move relative to each other at least a predetermined distance along the longitudinal axis of said piston rod, wherein, in said locked position, locking portions of said first portion and said second portion are in interengagement so as to restrict relative movement between said first portion and said second portion along the longitudinal axis of said piston rod, said first portion having a portion with an enlarged cross-section in said locked position, and, wherein, in said unlocked position, said enlarged portion of said first portion being deflected radially inwardly by direct contact with said body to have a smaller diameter cross-section than in said locked position thus causing said locking portions of said first portion and said second portion to be out of interengagement and permit relative movement between said first portion and said second portion along the longitudinal axis of said piston rod.