| 摘要 |
A nonreusable medical device has a needle (34) for injecting or collecting fluid which is retractable by depression of a plunger (54) slidingly mounted in the medical device. A front-mounted retraction mechanism (22) has a needle holder connected to the needle. The needle holder is supported along the axis of the device by means of a frictionally engaged retainer ring (102) member coupled to the needle holder along an axially aligned sliding interface. The needle holder and retainer ring are positioned in the front portion of a hollow body. The front of a movable member or plunger presses against the retainer member passing around the needle holder which cannot move forward, thereby separating the retainer member from the needle holder. The separation occurs by gradually reducing the extent of the sliding interface area until the retainer member pops loose from the needle holder whereupon the needle holder and needle are retracted into a cavity in the plunger in response to a retraction force applied to the needle holder by a previously compressed spring.
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