| 摘要 |
A safety syringe with a needle sleeve is provided. The needle sleeve is put around a cap of the syringe, such that the cap, a hub tightly fitted in the cap, and the needle sleeve together form a needle sleeve assembly, which allows the hub to temporarily locate closely before but not engaged into a neck portion of a barrel of the syringe, so that the syringe may be sterilized under high temperature without stress and thermal deformations at the joint of the hub and the barrel. When the cap is depressed in a predetermined manner, the hub and a cannula held thereto are caused to move backward and be stably retained to the neck portion of the barrel in an airtight manner. And when the cap is pulled forward again, it brings the needle sleeve along with it to separate from the hub to expose the cannula for injection. The needle sleeve may be provided with two stoppers to prevent the cap from being undesirably depressed. When the cap is turned to disengage from the stoppers of the needle sleeve, the cap may be depressed to push the hub into the barrel.
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