Adapter for injection device

Injection or infusion device, comprising a) a housing (1) with a receiving compartment (4) into which a container for an injectable product can be inserted, wherein in said container for administration of the product, a piston is accommodated to be displaced in a advancing direction towards an outlet of the container, b) drive means having a piston rod (5), with which the piston is screwed upon insertion of the container into the receiving compartment (4), and c) an adapter (10) with a thread (12) (for closing the storage compartment 4) in the longitudinal direction of the piston rod (5) is on the piston rod (5) to the housing (1) screwed and fixing of the container in the receiving compartment (4) and serves as a connection between the product container and a catheter, in which the adapter (10) has a retaining means, secured against rotation by means of the container to the adapter (10) can be held, wherein the adapter (10) is designed such that - in the receptacle during insertion of the receptacle (4), first the adapter (10) some distance into the receptacle (4) is screwed, - passes through the screwing of the adapter and the piston in contact with the piston rod (5), and - upon further screwing in of the adapter (10) and the associated holding device due to the rotational movement of the container and the piston on the piston rod (5) is screwed.