US Patent 7699802 Needle-less injector

A needle-less injector device that includes an outer housing and an inner housing that is slideably supported from the outer housing is disclosed. The inner housing supporting a vial that includes a nozzle for delivering a fluid held within the vial. A spring powered ram that is adapted for pushing a seal and plunger is mounted within inner housing. A skin tensioning spring mounted between the inner housing and the outer housing is used for pushing the leading end of the inner housing away from the outer housing. A trigger that cooperates with the spring-powered ram is used to release the ram from the cocked position only when the inner housing is in a firing position.