Syringe having a spring action plunger rod

摘要

A syringe assembly including a syringe barrel defining a chamber having a stopper therein is disclosed. The syringe assembly includes a plunger rod associated with the stopper, the plunger rod includes an outer sleeve having a distal end interconnected to the stopper and a sidewall portion defining an opening therein. The plunder rod also includes an inner sleeve disposed within the outer sleeve including a longitudinally extending track in alignment with the opening in the outer sleeve. The inner sleeve is adapted for telescopic movement with respect to the outer sleeve. The plunger rod also includes a spring mounted in association with the inner sleeve. The syringe assembly further includes a holding mechanism associated with the plunger rod and configured for cooperation with the inner and outer sleeves. Relative movement between the inner and outer sleeves causes the plunger rod to transition from a collapsed position to an extended position.

主权项

1. A syringe assembly comprising:
a syringe barrel having a first end, a second end, and a sidewall extending between the first end and the second end defining a chamber; a stopper disposed within the chamber of the syringe barrel; a plunger rod associated with the stopper, the plunger rod comprising:
an outer sleeve having a distal end interconnected to the stopper, the outer sleeve comprising a sidewall portion defining an opening therein;an inner sleeve disposed within the outer sleeve, the inner sleeve including a longitudinally extending track, at least a portion of the track being in alignment with the opening in the outer sleeve, wherein the inner sleeve is adapted for telescopic movement with respect to the outer sleeve; anda spring mounted in association with the inner sleeve; and a holding mechanism arranged on the outer sleeve and configured to cooperate with the track in the inner sleeve, wherein the holding mechanism holds the plunger rod in a pre-use position wherein the spring is held in a compressed position and relative movement between the inner sleeve and the outer sleeve causes the spring to be released from the compressed position and the plunger rod to transition from the collapsed pre-use position to an extended ready-to-use position.