IT1227272B - Safety syringe with piston to prevent users from having any kind of needle contact before and after use and from using said syringe more than once - Google Patents

Abstract

The present invention concerns a new syringe comprising a hollow cylinder, a piston with a needle, a little membrane and a spring, said components being assembled adequately but differently from traditional syringes. Indeed said needle is not set on the nib of said hollow cylinder, but rather at the base of said piston; the hollow cylinder is not provided with a nib at its base, but rather a membrane of variable thickness that closes the hole; said piston is provided with a spring fixed to the very piston on one side and to said cylinder on the other side to take back the piston.The functioning of said syringe develops through different phases.In the first phase the piston is pushed making the needle come out from the cylinder through the membrane that closes the hole at the base of said cylinder. By either loosening a bit the piston or by manually pulling it upwards, the needle sucks the fluid into the cylinder cavity. It is envisaged that suction be longer with respect to the fluid to be sucked, therefore air will also be sucked. As suction is carried out by means of the needle set on the piston, at the end of said suction the needle will draw back into said cylinder again.During the second phase sucked air will be taken out to allow the needle to partially come out from the cylinder without fluid wastes. This very operation is of utmost importance, as needle can be guided to the exact point of use.During the third phase injection is carried out simultaneously to needle penetrationIn the fourth and last phase the needle is automatically drawn back into the cylinder cavity by the spring.Indeed, one of the benefits of the present invention is that this new syringe is that it protects users from needle contact both before and after injection. Another benefit is that it is impossible to use the present syringe more than once. For this purpose a peculiar syringe body was designed, said body being formed by two parts with gradual fitting, which occurs each time the needle encounters a resistance. For example, during the aforementioned first and second phases the needle encounters membrane resistance, and each time a resistance occurs both bodies embed in one another. In case a third resistance occurs, an internal prominence of the piston will close the needle chute, thus making both injection and suction impossible.