Abstract In a syringe with a hollow cylindrical barrel with one closed end, a plunger having a length longer than the barrel mounted in the barrel for reciprocation, a handle on the distal end of the plunger extending from the barrel and a piston mounted on the opposite end of the plunger in the barrel and a hypodermic needle mounted in the closed end of the barrel being in communication with the interior of the barrel, the improvement of including a hollow tapered section in the barrel adjacent to its closed end, which tapered section in cooperation with the piston end of the plunger is operable to disable the syringe as the piston commences traversing this tapered portion of the barrel. A desired embodiment has the tapered section or portion formed by a separate sleeve slidably mounted in the barrel with the hypodermic needle mounted in this sleeve with means to engage the sleeve whereby withdrawing the plunger from the barrel after its piston end has entered this tapered section will pull the sleeve and the attached needle into the barrel thereby preventing persons from thereafter being "pricked" by the sharp end of the "used" needle.
In a disposable syringe having a hollow cylindrical barrel closed at one end, a plunger having a length longer than said barrel mounted in said barrel for reciprocation, said plunger having a handle on its end extending from the barrel and a piston mounted on the opposite end of said plunger received in said barrel and a hypodermic needle mounted in said closed end of said barrel being in communication with the interior of said barrel, the improvement comprising: a tapered section formed in said barrel adjacent to its closed end which has a decreasing diameters from its central section to its closed end; and disabling means associated with said piston end of said plunger operable to prevent re-use of said syringe once said disabling means has commenced traversing said tapered portion of said barrel, said disabling means including a collapsible piston core operable to be diminished in diameter by the tapered portion as the piston traverses said tapered portion of the barrel whereby said piston will not thereafter seal with the internal bore of said barrel if said piston is thereafter extracted from said tapered portion.
Claim 2
Dependent Claim
187 words
In a disposable syringe having a hollow cylindrical barrel closed at one end, a plunger having a length longer than said barrel mounted in said barrel for reciprocation, said plunger having a handle on its end extending from the barrel and a piston mounted on the opposite end of said plunger received in said barrel and a hypodermic needle mounted in said closed end of said barrel being in communication with the interior of said barrel, the improvement comprising: a tapered section formed in said barrel adjacent to its closed end which has a decreasing diameters from its central section to its closed end; and disabling means associated with said piston end of said plunger operable to prevent re-use of said syringe once said disabling means has commenced traversing said tapered portion of said barrel, said disabling means including a collapsible piston core operable to be diminished in diameter by the tapered portion as the piston traverses said tapered portion of the barrel whereby said piston will not thereafter seal with the internal bore of said barrel if said piston is thereafter extracted from said tapered portion.
Claim 3
Dependent Claim
52 words
The improved syringe defined in claim 1 where the disabling means includes a joint between the piston and the plunger and a compressible means associated with said joint operable to separate said joint to disconnect said piston from said plunger when said compressible means commences traversing the tapered portion of the barrel.