Torsion spring driven injection device

The present invention relates to a torsion spring driven injection device for delivering set doses of a liquid drug. The injection device mechanism is encapsulated in a housing which also stores the cartridge containing the liquid drug. A needle cannula which is in liquid communication with the interior of the cartridge and which has a distal tip is shielded by a telescopically movable needle shield is used to inject the set dose. The needle cannula is preferably used for multiple injections and cleaned between subsequent injections. The drive mechanism further comprises a nut member engaging the piston rod and releasable coupled to the housing to operate as a pressure relief mechanism. The telescopically movable needle shield covering the distal tip of the needle cannula is formed to lock the nut member to the housing during injection. 本发明涉及用于输送液体药物的设定剂量的扭力弹簧驱动的注射装置。注射装置机构被封装在壳体中，壳体还储存容纳液体药物的套筒。针插管用于注射设定剂量，针插管与套筒的内部液体连通且其具有通过能伸缩地运动的针护罩保护的远端末端。针插管优选地用于多次注射且在随后的注射之间被清洁。驱动机构还包括螺母构件，其接合活塞杆且能释放地联接到壳体以作为卸压机构操作。形成覆