| 摘要 |
<p>A hypodermic syringe includes a housing (1), a plunger (2) with an associated piston (3), a needle carrier (4) with a needle (5) covered by a removable sheath (6). A vacuum is formed between the plunger (2) and piston (3). When the plunger (2) is operated, the piston (3) engages the needle carrier and a coupling between the plunger and piston is broken, so that the vacuum withdraws the piston (3) into the plunger (2), together with the needle carrier, so as to retract the needle into the housing (1). The needle carrier (4) is rectangular in cross-section and is received in a corresponding rectangular sectioned housing opening (1.2) in order to prevent rotation of the needle carrier relative to the housing. This facilitates removal of the needle sheath, without the risk of a needle stick injury prior to use of the syringe, and allows for the separate and external fitting of a needle.</p> |
