| 摘要 |
A hypodermic safety syringe assembly ( 10 ) includes a cylindrical barrel ( 12 ) having a front end defining a first aperature ( 14 ) and a rear end defining a second aperature ( 16 ), a closure member ( 32 ) shaped to engage the barrel ( 12 ) at or adjacent the front end thereof to seal the first aperature ( 14 ), and a piston assembly ( 18 ) reciprocally movable within the barrel ( 12 ) and includes a retractor ( 20 ) terminating in a piston formation ( 24 ) engageable with the closure member ( 32 ) to disengage the closure member from the front end of the barrel so that a hypodermic needle ( 40 ) attached thereto can be withdrawn into the barrel ( 12 ) after use, wherein the closure member ( 32 ) includes a barrel engaging formation ( 44,48 ) releasably engageable within a closure member engaging formation ( 64 ) at the front end of the barrel ( 12 ), and a piston coupling formation ( 50,54 ) for engaging a closure member coupling formation ( 68,69 ) on the piston ( 24 ), with inter-engagement of the piston and closure member coupling formations ( 50,54;68,69 ) being arranged to facilitate disengagement of the barrel engaging and closure member engaging formations ( 64; 44,48 ) from one another and to allow withdrawal of the piston assembly ( 20,24 ), closure member ( 32 ) and hypodermic needle ( 40 ) into the barrel ( 12 ). |
