Injection device with drug depot

摘要

The invention relates to an injection device with drug depot, especially for insulin, on the ball point pen principle, with which two insulin units can in each instance be injected by pressure on a button. A tubular piston rod that moves the syringe piston is arranged so as to be longitudinally movable in the rear part of the cylindrical housing and has several circumferential grooves, which correspond to the number of metering steps, with profiles representing isosceles triangles. The follower sleeve provided with bores uniformly distributed over the circumference can be displaced longitudinally on the piston rod. Pins whose end facing the piston rod represents a truncated cone with an apex angle corresponding to the basic angle of the grooves are inserted in the bores. In the top region of the push-tube there is a conical bore which engages with the pins during the metering process and has an angle of inclination that is slightly larger than the flank angle of the grooves on the piston rod.