| 摘要 |
PURPOSE: A single use syringe for subcutaneous injection is provided to produce an inexpensive injection barrel made of a medically acceptable material with a spring lock clip and its associated plunger for converting a normal syringe to a disposable one. CONSTITUTION: The single use syringe(10) comprises:a hollow barrel(12); a rod-like plunger(14) made of a plurality of frusto-conical or bead-like ratchet teeth(28); and a radially resilient, spring locking clip(40) dangling on the ratchet portion of the plunger. The clip determines the maximum dosage which can be administered by the syringe. Aspirating gaps(114) is provided on the plunger rod to allow selective aspiration prior to loading and dispensing medication. In use, a first withdrawal of the plunger with respect to the hollow barrel(12) allows, for aspiration, then medication can be drawn into the cavity of the barrel since the cam tooth(83) of the locking spring clip glides, by radial flexing, over the surface of the ratchet teeth and, yet, the locking spring is maintained in relative position along the barrel by outwardly directed contact points embedding into the interior sidewall of the barrel(12).
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