Patent ID: 7947020
Filing Date: 2011-05-24
Classification: A61M

Abstract:
1. A retractable safety syringe, comprising: a syringe body defining a distal portion, a proximal portion and an inner surface, a detent formed on the inner surface; a plunger having a piston slideably disposed within the syringe body and a shaft extending through the proximal portion, the piston having a protuberance extending toward the distal portion of the syringe body, a distal seal disposed between the plunger piston and the syringe body forming a fluid tight seal between the plunger piston and the syringe body; and a needle holder engageable to the piston, the needle holder having a lower undercut groove sized and configured to receive the detent defining a retaining force, the lower undercut groove removeably engaged with the detent removeably fixing the needle holder to the distal portion of the syringe body, the needle holder having a cavity sized to receive the protuberance of the piston; wherein a retraction force tending to move the piston toward the proximal portion of the syringe body arises when the piston is traversed toward the distal portion of the syringe body, and wherein the retraction force is greater than the retaining force when the piston is engaged with the needle holder.