Patent ID: 9272097
Filing Date: 2016-03-01
CPC Classification: A61M

Claim Text:
1. A retractable safety syringe for preventing accidental needle pricking and needle reuse after completion of an injection stroke, the syringe comprising: a syringe body defining a proximal portion and a distal portion; a needle removeably engageable to the body distal portion; a piston disposed within the syringe body and biasable to the body proximal portion via a vacuum force when the piston is traversed toward the syringe body distal portion, the piston being traverseable between a retracted position and an engaged position; a shaft attached to the piston and disposed within the body, at least one of the shaft and the syringe body including a seal, the shaft extending through the proximal portion of the body; a vacuum chamber disposed within the syringe body, the vacuum chamber located intermediate the piston and the seal, the vacuum chamber configured to provide the vacuum force on the piston in a direction from the syringe body distal portion toward the syringe body proximal portion upon movement of the piston toward the syringe body distal portion responsive to the distal translation of the piston; and a fluid chamber disposed within the syringe body, the fluid chamber located distally from the piston, the fluid chamber having a distal end and a proximal end, the proximal end of the fluid chamber being sealed, the fluid chamber in fluid communication with the needle through the distal end of the fluid chamber and configured to be reduced in volume as the piston is traversed towards the engaged position, and wherein at least one of the shaft and the syringe body includes an engaging portion and a non-engaging portion, traversal of the shaft through the syringe body operative to traverse the piston within the syringe body between a storage position and working positions, the engaging portion proximate the seal and in sealing engagement with the seal in the working positions and the non-engaging portion proximate the seal and in a substantially non-sealing engagement with the seal in the storage position.