| 摘要 |
A medicinal syringe including a tubular plunger from which air has been evacuated and a seal member releasably attached on the distal end of the plunger. Upon application of a predetermined longitudinal axial force to the seal member, the attachment between the seal member and the plunger will rupture, releasing the seal member for movement within the plunger. The seal member when released will be forced by the differential pressure between the vacuum and the ambient air into the interior of the tubular plunger. The plunger is slidably disposed in a tubular barrel. A needle is disposed in a hub releasably attached within the distal end of the barrel. Upon application of a predetermined longitudinal axial force to the hub, the attachment between the hub and the barrel will rupture, releasing the hub for movement within the barrel. The hub when released will be forced by the pressure differential, along with the distal plunger seal member, into the interior of the tubular plunger, carrying the needle with it. The attachment between the hub and barrel is adapted to rupture prior to that between the seal member and plunger. Once drawn into the tubular plunger, the needle and hub will remain there indefinitely, thus eliminating accidental puncturing by the needle of a person in the vicinity of the syringe.
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