Threaded rod or piston rod for injection device i.e. fixed-dose pen, has four teeth and outer thread, where intervention unit of device is engaged in grooves to hold rod in rotation position or to rotate rod in preset turn by grooves

摘要

The threaded rod or piston rod has four teeth (5b), an outer thread and four grooves (5a) that run in a axial and longitudinal direction of the rod. An elastic intervention unit of an injection device is engaged in the grooves to hold the rod in a predetermined rotation position by the grooves or to rotate the rod in a predetermined turn by the grooves or by a distance of other grooves. Claws or bars are attached at an end of the bolt and at an extension that is provided at a proximal side of the rod.