GAS PRESSURED NEEDLE-LESS INJECTION DEVICE

摘要

A needle-less injector suitable for injecting fluid through a skin surface of a patient includes a housing, a driver, an intruding gas chamber activating mechanism and a trigger. The housing containing the fluid and a sealed gas storage chamber containing a gas. The driver forces the fluid out of the housing at a sufficient speed to pierce the skin surface of the patient. The intruding gas chamber activating mechanism is mounted in the housing to intrude through the sealed gas chamber to release gas seal into the housing. The trigger is operatively coupled to the intruding gas chamber activating mechanism to release the gas from the gas chamber into the housing to activate the driver to force the fluid out of the housing. The trigger is activated by moving the trigger towards and orifice in the housing and/or upon application of a predetermined amount of pressure to the trigger that is opposed by a predetermined amount of resistance from the skin surface of the patient. The predetermined amount of resistance results from the housing having contact with the skin surface of the patient, and when this predetermined amount of resistance is reached the liquid medication is forced out of the housing by the driver to pierce the skin surface of the patient. In particular variations, the intruding gas chamber activating mechanism includes a valve member that is displaced and intrudes into the sealed gas chamber to release the gas from the gas chamber.