Patent ID: 6572584
Filing Date: 2003-06-03
Classification: A61M

Abstract:
A reduced force syringe plunger handle for use in retracting a retractable syringe of the type having an elongated hollow syringe barrel having a front end portion containing a retraction mechanism activated by forward movement of the plunger relative to the barrel, the retraction mechanism comprising a rearwardly biased needle holder held by a separable retainer member lodged in the front end portion of the barrel, the retainer member having first and second sides oppositely disposed relative to a longitudinal axis through the barrel, the syringe plunger handle having a tubular body reciprocatably mounted in the barrel, the tubular body having a head comprising a front tip configured to contact and separate the retainer member from the needle holder by forward movement of the plunger relative to the barrel thereby releasing the needle holder for retraction, wherein the improvement comprises:the front tip of the plunger having a longitudinally varying front surface comprising a first forwardly extending side configured to contact and move the first side of the retainer member relative to the needle holder and the barrel, and a second forwardly extending side disposed rearwardly of the first forwardly extending side, the second forwardly extending side configured to thereafter contact and move the second side of the retainer member relative to the needle holder and the barrel when the plunger is moved forwardly relative to the barrel, thereby reducing the plunger force required to activate the retraction mechanism.