| 摘要 |
A needle-covering sleeve (14), slidably fitted on the syringe barrel (1), is held in its retracted rest position by means of retaining tongues (10), which hook it at its rear rim (13). At the end of the injection stroke of the plunger (2), a rear flange (8) of the stem (3) of the plunger (2) radially opens the retaining tongues (10) apart, which release thereby the needle-covering sleeve (14). Then, the latter is axially advanced by means of a spring (16), to an advanced safety position, in which it entirely covers the needle (5) and is fastened to a sleeve-clamping ring (18), which is provided at the fore end of the syringe barrel (1). To this purpose, the sleeve-clamping ring (18) has peripheral elastic retaining tongues (19) which interact with matching retaining teeth (20) on the inner part of needle-covering sleeve (14) and prevent any axial backward movement of the needle-covering sleeve (14). Further, the sleeve-clamping ring (18) is a stop abutment, cooperating with an inner projection of the needle-covering sleeve (14) and preventing any further axial forward movement of such sleeve.
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