Disposable syringe with a retractable needle

摘要

A disposable syringe includes a barrel (1) having a retaining region (121) to retain a needle seat (21) for carrying a needle cannula (22), and a friction diminishing region (122) extending forwardly from the retaining region (121) and terminating at a shoulder abutment (124), a plunger (4) movable in the barrel (1) toward the needle seat (21), and a coupling member (51) biased by a biasing member (52, 54) and having a retained portion (512) to frictionally engage the plunger (4), and an anchored portion (514) to engage an anchoring portion (213) of the needle seat (21) such that when the needle seat (21) is moved past the friction diminishing region (122) to abut against the shoulder abutment (124), a subsequent pushing force applied to the plunger (4) results in release of the retained portion (512) from the plunger (4), thereby enabling the anchored portion (514) to be moved into the plunger (4) by means of the biasing member (52,54).