Suction injector having an adjustable dosing device

A suction injector having a dosing mechanism, comprising a tubular container for storing a multiple dose of a liquid medicine;

• a piston arranged for movement in said container;
• an exchangeable cannula connected to one end of said container;
• a container housing adapted for accommodating said container;
• a suction cup attached to one end portion of said container housing to pull up the skin of a patient against said cannula;
• an underpressure generator including a pressure gas container and a pump connected to said suction cup, said under-pressure generator being attached to said container housing and communicating with said suction cup;
• pressure controlling means having a control valve and disposed between said suction cup and said underpressure generator to control the pressure conditions in said suction cup;
• a non-return valve coupled between said under-pressure generator and said suction cup to maintain under-pressure in said cup when the suction from said pump is interrupted;
• and a dosing mechanism arranged on said container housing and coupled to said piston in said container to permit an incremental movement of the piston toward said cannula, the end of said container housing opposite said cannula being hermetically sealed by a closure cap and the space resulting between the cap and the upper surface of said piston communicating through said control valve with said pressure gas container in said under pressure generator to move said piston about a predetermined increment.