Disposable medicament injector

A disposable medicament unit comprising:

• a cylindrical barrel having inner and outer surfaces and open on both its front and rear ends,
• a plunger slidably carried in the rear end of the barrel in sealingly relation to the inner surface of the barrel,
• a diaphragm assembly fixedly mounted in the forward end of the barrel, said diaphragm assembly including a hollow body portion having inner and outer surfaces, said hollow body portion fitting within the cylindrical barrel with its outer surface sealingly engaging the inner surface of said cylindrical barrel, a flexible wall closing off one side of the body portion to form a medicament chamber between the plunger and the flexible wall, a needle supported by the hollow body portion, said needle being spaced from the flexible wall and outside the medicament chamber, said needle being adapted to pierce the flexible wall when said wall is flexed into contact therewith to establish fluid communication between the medicament chamber and the needle,
• a nose cap assembly fitting on the forward end of the barrel, and
• this nose cap assembly includes a body portion with an inner and an outer wall extending rearwardly therefrom and being spaced so as to snugly receive the forward end portion of the barrel therebetween.

A disposable medicament injector comprising:

• a cylindrical glass barrel open at both its rear and forward ends and having an inner and an outer surface,
• a plunger slidably carried in the barrel adjacent the rear end thereof, said plunger sealingly engaging the inner surface of the barrel,
• a diaphragm assembly mounted in the forward end of the barrel, said diaphragm assembly comprising a cylindrical diaphragm body snugly engaging the inner surface of the barrel, the forward end of the diaphragm body being open and the rear end being closed by a flexible end wall to form a medicament chamber between the plunger and the aforesaid flexible end wall, a needle mount fitted within the diaphragm body, a needle carried by said needle mount, the rear end of the needle being spaced from the flexible end wall whereby when the plunger is forced forwardly the end wall will flex and be brought into contact with the rear end of the needle to cause the needle to pierce the end wall and allow the medicament to flow through the needle,
• a finger grip mounted on the rear end of the barrel, said finger grip including a circular body with a pair of finger grip elements extending diametrically outward from the body and generally perpendicular to the glass barrel, an outer and an inner wall extending forwardly from the circular body and spaced from each other a distance equivalent to the thickness of the glass barrel to form a barrel receiving space whereby the glass barrel is inserted into the aforesaid space so that the inner and outer surfaces of the barrel are snugly gripped by the respective and confronting surfaces on the inner and outer walls,
• a nose cap mounted on the forward end of the barrel, said nose cap including a body portion having a central opening therethrough, inner and outer walls extending rearwardly from the body portion, said inner and outer walls being spaced from each other to form a space into which the forward end of the barrel is inserted whereby the inner and outer faces of the barrel are gripped by the confronting surfaces of the inner and outer walls to retain the nose cap in the barrel, and
• cannula hub receiving means extending forwardly from the nose cap body and in fluid communication with the opening in said body, said cannula hub receiving means being adapted to mount a cannula assembly which is in fluid communication with the cannula hub receiving means.