| 摘要 |
2124574 9310842 PCTABS00022 A syringe, comprising a casing (1) with a piston/piston rod assembly (9, 10) slidable therein and a needle foot (6) latched to a first end of the casing, means being provided to couple the piston with the needle foot and to unlatch the needle foot in an inner extreme position of this assembly in order to be able to withdraw the needle foot with the piston into the casing and thereby to shield off the needle (7) fixed to the needle foot and, as the case may be, to destroy this needle, stroke limiting means (15, 18) being provided which are adapted to limit the stroke length in such a way that the piston remains at a predetermined distance from the needle foot when the piston is pushed inward for the first time to eject the air, and after the withdrawal of the piston for drawing in the injection fluid, to increase the stroke length in such a way that the piston can be coupled with the needle foot when the piston is thereafter pushed inwards again for the ejection of the injection fluid. The means to limit the stroke comprise a ring (18) which, is either slidable by interaction with this assembly, over a predetermined distance with respect to this assembly or to the casing after the assembly has been drawn outwards at least once, or is rotatable and is provided with abutments staggered to each other over the predetermined distance, so that, when the assembly slides, this ring is turned in such a way that, finally, the assembly can be pushed inwards up to the deepest abutment.
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