Patent ID: 7494479
Filing Date: 2009-02-24
Classification: A61M

Abstract:
1. A hypodermic syringe comprising a barrel including an open end and a hub end having a hub retainer; a plunger including a seal end slidably disposed in the barrel, an outer end extending from the open end of the barrel, a cavity between the outer end and the seal end, a mounting hole extending longitudinally of the plunger through the seal end to the cavity and a driver surface on the seal end; a mandrel in the mounting hole; a spring element in the cavity fixed to the mandrel at a first end and fixable relative to the plunger in tension at a second end; a needle hub in the hub retainer, the hub end of the barrel including resiliently mounted dogs releaseably retaining the needle hub from movement longitudinally into the barrel and engageable with the driver surface to release the needle hub for movement longitudinally into the barrel, the hub retainer having a bore and a first shoulder in the bore facing the plunger and being normal to the longitudinal direction of the barrel, the needle hub including longitudinally extending ribs about the needle hub defining a second shoulder on the ends thereof facing the first shoulder and being normal to the longitudinal direction of the barrel, a first position with the needle hub against the dogs, a second position with the second shoulder against the first shoulder, the first and second positions being displaced from one another.