Patent ID: 6918889
Filing Date: 2005-07-19
Classification: A61M

Abstract:
1. A single-use injection device comprising: a syringe, comprising an injection needle, and delimiting a chamber filled with a dose of fluid to be injected, which is sealed by a plunger which is integral with one of the ends of a plunger rod, which is provided with a thruster at its opposite end; a syringe body which is integral with the syringe; a protective case; means for relative locking in translation, provided on the syringe body and the protective case, in order to permit relative displacement of the protective case and of the syringe and syringe body assembly, between a position of injection, in which the injection needle is released, and a position of protection after use, in which the injection needle is accommodated inside the protective case, wherein the injection device comprises: resilient means, which are disposed between the syringe body and the protective case, such as to be compressed in the position of injection of the latter; and a locking ring, which is provided with digital support means for injection of the fluid, and units for locking in translation of the ring, which can maintain the ring in a position in which it locks the means for locking in translation of the protective case and of the syringe and syringe body assembly, in the position of injection of the latter, in the absence of force exerted on the digital support means, and for a force exerted on the latter, which is equivalent to the reaction force generated, thus leading to sliding of the plunger, and in order to permit axial displacement of the ring towards a position in which it releases the locking means, and permits relative displacement of the protective case and of the syringe and syringe body assembly, towards the position of protection, after use of the latter, by means of the action of the resilient means, for a force exerted on the digital support means, which is greater than the reaction force which is generated for the purpose of sliding of the plunger, and is obtained when the plunger has reached its end of travel.