INJECTION METHOD AND APPARATUS

摘要

A pen-type injector for receiving a medication containing member. The injector comprises a housing (1) and a torsion spring (4) contained within the housing and coupled to a drive member (8). A dose setting knob (2) is coupled to the spring (4), and rotatably coupled to the housing (1) such that rotation of the knob relative to the housing in a first direction results in compression or twisting of the spring. A user actuable trigger (12) is provided for releasing the spring (4) to push the drive member (8) through the housing (1). A user actuable button (6) is coupled to the housing (1) for axial motion relative thereto, said button (6) being coupled to the torsion spring (4) to cause the spring to unwind or expand in discrete steps with each press of the button.