Patent ID: 7267664

Claim:
A self-locking safety disposable syringe with needle protection after use, comprising: a hollow barrel ( 1 ) having at one end an internal seat ( 2 ); a hub ( 3 ) carrying a cannula ( 4 ); a hollow driving rod ( 5 ), housing a spring ( 6 ), disposed in the hollow barrel ( 1 ); and an extracting element ( 8 ) on the rod for extracting the hub ( 3 ) from the internal seat ( 2 ), wherein the extracting element ( 8 ) has an annular notch ( 9 ) in which an annular sealing gasket ( 10 ) is disposed, of such a size as to seal against the internal wall of the hollow barrel ( 1 ) both when sucking and when compressing the liquid to be injected; said extracting element ( 8 ) with said sealing gasket ( 10 ) operating as a sucking and compressing piston; and wherein on the inside of said end of the hollow barrel ( 1 ) two small semicircular projections ( 21 ) and ( 22 ) are provided, that are able to press, by reaction to the thrust of an operator's thumb on the hollow driving rod ( 5 ) of the extracting element ( 8 ), against a flat part ( 11 ) of the sliding extracting element ( 8 ) and simultaneously to form a small circular recess ( 23 ) for housing the annular sealing gasket ( 10 ) when, at the end of an injection, said sealing gasket ( 10 ) separates from said annular notch ( 9 ).