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Non-reusable syringe

  • US 5,181,912 A
  • Filed: 12/05/1991
  • Issued: 01/26/1993
  • Est. Priority Date: 12/05/1991
  • Status: Expired due to Fees
First Claim
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1. A non-reusable syringe, comprising:

  • an elongate cylindrical barrel having adapter means on one end for attachment of a needle, and an open other end;

    a two-piece plunger and piston assembly reciprocable in the barrel between a forward position in the barrel and a retracted position, said plunger having a forward end in the barrel and a rearward end accessible exteriorly of the barrel for operating the plunger;

    said piston being carried directly on the forward end of the plunger for effecting a sliding seal with the barrel to draw material into the barrel and discharge it therefrom through said one end upon reciprocating motion of the plunger and piston assembly in the barrel; and

    releasable latching means on the piston and plunger for latching the piston to the plunger during initial retraction of the plunger and piston in the barrel, and for unlatching the piston from the plunger during forward movement thereof, so that the piston becomes disengaged from the plunger during subsequent retraction of the plunger in the barrel, said latching means including latching arms integral with the forward end of the plunger and extending radially outwardly into sliding contact with an inner surface of the barrel, said latching arms having a first position in latching engagement with detent means on the piston to retain the piston on the plunger, and being movable to a second, over-center, unlatched position releasing the piston from the plunger as the plunger is reciprocated first toward and then away from said one end of the barrel.

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