| 摘要 |
<p>A tamper proof retractable non-reusable syringe (10) has a one piece hollow outer body (12) with a barrel (14) for a slidable plunger, a transition zone (18) and a smaller diameter nose portion (16). An elongated needle holder (22) and spring (24) combination is installed from the rear of the outer body, guided into the nose portion and held by cooperating inwardly and outwardly facing surfaces oriented in the direction of retraction at the most constricted part of the transition zone where the nose begins. The plunger has an opening with a dislodged stopper (42) for receiving parts of the retraction mechanism (20). The stopper and the head of the needle holder are of significantly reduced diameter from the injection fluid chamber to resist blowing out prematurely. In one embodiment the head of the needle holder is surrounded by a separable retainer member which is slide removed by contact with the tip of the plunger after the stopper is mostly or fully removed to avoid cumulation of force required for retraction after the injection.</p> |
