Safety syringe

A safety syringe comprising:

• a barrel including a diameter-reduced neck portion extending axially therefrom, said neck portion having terminating at an open front end portion, said open front end portion defining an inclined first inner peripheral wall extending axially rearward and radially inward to form a first shoulder portion, said neck portion defining a second inner peripheral wall extending from said first shoulder portion in gradually diametrically reduced manner to a rear end thereof;
• a hub coaxially coupled to said barrel having a cannula fixed to a front end thereof, said hub having an intermediate portion extending axially from said front end to a rear end, said hub including a second shoulder portion circumscribing said intermediate portion for engaging said first shoulder portion of said barrel, said intermediate portion having formed therein adjacent said rear end a pair of diametrically opposed receiving hole openings, said intermediate portion defining an outer peripheral wall portion frictionally engaging said second inner peripheral wall of said barrel neck portion in substantially flush manner, said outer peripheral wall portion being gradually reduced in diameter between said second shoulder portion and said rear end;
• a cap removably covering said cannula and at least a portion of said hub;
• and,
• a plunger removably disposed in said barrel for injecting a medical liquid from within said barrel into a patient's body through said cannula, said plunger being an elongated member inserted into said barrel via an opening provided at a rear end of said barrel, said plunger having a stopper disposed at a front end thereof and an engaging cone projecting axially from a front end of said stopper for engaging said receiving hole openings of said hub intermediate portion upon substantially full insert of said plunger into said barrel;
• said first and second shoulder portions forming a first airtight contacting surface joint therebetween when said hub is assembled with said neck portion of said to prevent detachment of said hub from said barrel neck portion, and said outer peripheral wall portion of said hub forming a second airtight contacting surface joint against said inner peripheral wall of said barrel neck portion.