| 摘要 |
A hypodermic syringe is rendered non-reusable by means of a special latching device that prevents a portion of the piston from being retracted and that causes that portion to seal off the syringe at the end of it to which the needle is attached. The latching device is lodged into a groove recessed into the cylindrical inner surface of the syringe like a snap ring, and includes elastically deflectable fingers that extend axially and slightly inwardly radially in the direction toward the needle, so that the tips of the fingers extend into the path of the piston, are elastically deflected aside by the piston and spring inward again after the piston has passed, thereby blocking movement of the piston in the opposite direction and rendering the syringe non-reusable.
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