Abstract: A disposable 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. The plunger is slidingly and sealingly disposed in the barrel of the syringe. A luer lock assembly is mounted within the barrel and includes a releasable hub portion which is securely engageable with the releasable plunger seal member, the securely engaged members when released being actuated by ambient air pressure into retraction into the evacuated plunger. The luer lock assembly is adapted for receiving a hypodermic needle or other medical device.

Abstract: 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.