The image processing handbook (3. ed.)

A device for injecting medicament without the use of a needle is disclosed wherein medicament is expelled from the device at high pressure, caused to break the skin of a patient, and appropriately forced into the patient's body. A preferred embodiment of the present invention is a jet injector having a piston slidably movable within a medicament chamber to selectively change the volume of the medicament chamber and a mechanism for advancing the piston including releasably held springs which may be compressed by a winding mechanism or pressurized fluid. Medicament is provided to the medicament chamber from a medicament container mounted on the injector by a container holder assembly including flexible fingers that can be caused to grasp the pierceable cap of the medicament container. Medicament is then selectively directed from the medicament container to the medicament chamber by valving which, in a first position, interacts with a safety to provide air to the medicament container during the filling of the medicament chamber and, in a second position, allows injection into the patient while the safety prevents movement of the valve member from the second position during injection and simultaneously blocks air communication to the medicament container.