Patent ID: 6752781
Filing Date: 2004-06-22
Classification: A61M

Abstract:
A gas powered hypodermic jet injection device, said device comprising:a device body having a forward end; an injection cylinder at the forward end of said device body, and said injection cylinder having a cylinder bore in which an injection piston is sealingly movable to cooperatively define a variable-volume chamber for holding a dose of liquid medication; said injection cylinder defining a fine-dimension injection orifice in liquid flow communication with said variable-volume chamber to receive and discharge liquid medication as a forceful high velocity jet upon forceful movement of said injection piston in said cylinder; a power source in said device body for forcefully moving said injection piston in said cylinder in response to communication of gas pressure to a gas pressure piston; said power source including a source of pressurized gas for selective communication with said gas pressure piston; a trigger assembly for selectively effecting communication of pressurized gas from said source to said gas pressure piston; and a lost motion preventing mechanism selectively drivingly connecting said gas pressure piston to said injection piston; wherein said lost motion prevention mechanism includes said gas pressure piston defining a bore, an injection ram interfacing at a forward end with said injection piston and adjacent to an aft end portion thereof being received into said bore and being selectively associated with said gas pressure piston, and said lost motion prevention mechanism in a first condition selectively allowing relative axial motion of said gas pressure piston and said injection ram, and also said lost motion prevention mechanism in a second condition selectively coupling said injection ram to said gas pressure piston for axial motion in unison therewith.