| abstract |
A needle-less injector comprises a cartridge ( 3 ) prefilled with liquid (( 9 ), which cartridge contains a free sliding piston ( 32 ) and an injection orifice ( 10 ). A ram ( 22 ) is urged by a pre-loaded spring ( 24 ) for striking the said piston to cause the injections. Adjusting means ( 6 ) can be provided to vary the volume injected. A trigger device ( 26, 30 ) initiates injection only when the optimum contact pressure is reached between the discharge orifice ( 1 ) and epidermis of the subject. The initial loading of the power spring ( 24 ) is sufficient to dispense all of the contents of the medicament cartridge in one dose or multiple sequential doses. Disposable and reusable embodiments are described. |