PRE-FILLED SYRINGE WITH RETRACTED NEEDLE, PISTON AND NEEDLE ASSEMBLY THEREFOR Russian patent published in 2012 - IPC A61M5/50 

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely syringes. A first object - a piston for the syringe comprising a retractable needle is designed to engage the needle and comprises a piston rod, an external portion of the piston, a control element and a displacement element. The rod, the external part of the piston and the control element are coupled for holding a released displacement element in an initially strained condition. The displacement element is released from the initially strained condition to retract the piston engaged with the needle. A second object - the syringe with the retracted needle, comprises a cylinder, the retracted needle and said piston. The piston is designed to engage with the needle thereby making it retracting after fluid delivery from the syringe. The third object - a released needle holding system attached to the syringe cylinder, comprises the retracted needle, a needle seal and a holding element. The needle comprises a body having a base engaged with the piston to provide retraction. The seal releasing the base is engaged with the piston. The holding element comprises a coupling surface joined to a coupling surface of an internal wall of the cylinder. The holding element initially holds the needle in a needle end of the cylinder until the needle is engaged with the piston to providing needle retraction. A fourth object - the syringe with the retracted needle comprises the cylinder, the piston and said released needle holding system. A fifth object - the pre-filled syringe with the retracted needle comprises a glass cylinder containing an internal wall and a bushing comprising a release ring; the released needle holding system; the piston engaged with a needle; and blocking systems. Said system comprises a needle assembly which comprises the needle and the needle seal; the holding element comprising the coupling surface joined to the coupling surface of the internal wall; and a pullback element for needle release from the holding element. Said piston contains an external part of the piston, the piston rod destructively coupled with the control element containing one or more coupling sections, a spring and a integral piston seal engaged with the needle. The rod, the external part of the piston and the control element are coupled to hold the released spring in initially pressed condition. One or more coupling sections of the control element are engaged with the external part of the piston until the release ring detach one or more coupling sections from the external part of the piston in the end of piston pressing, providing spring release and retraction of the retracted needle when engaged with the integral piston seal. Said blocking systems are provided respectively between: elements of the external part of the piston and the bushing; and the rod elements and the external part of the piston; for prevention of syringe reuse after needle retraction. A sixth object - a method for assembly of the syringe with the retracted needle involving the stages which provide: installation of the released needle holding system inside the cylinder of the syringe and introduction of the piston.

EFFECT: invention is user-friendly, has a minimal cost price, thereby promoting mass distribution of the syringes with the retracted needle, effectively delivers the fluid contents thereby minimising fluid loss.

31 cl, 19 dwg