| 摘要 |
<p>A syringe barrel and hypodermic needle assembly includes a barrel portion (21) having a chamber (22) for retaining fluid and a portion (23) extending from the distal end of the barrel portion having a passageway (26) therethrough. A projection (27) extends outwardly from the tip portion (23). A pierceable barrier (31) is provided for preventing fluid communication between the chamber (22) and the passageway (26). A hub (34) having a forward end, a rearward end and a conduit (38) therethrough is movably positioned within the passageway. A first cannula (39) extends outwardly from the forward end of the hub (34) and a second cannula (43) extends outwardly from the rearward end of the hub. A needle shield (46) movably engaging the tip (23), covers the first cannula (39). This needle shield has an outer extension portion (47) extending over a portion of the tip which is capable of contacting the projection (27) for limiting the motion of the needle shield toward the proximal end of the barrel (21). The outer extension portion (47) also includes a longitudinal groove (50) which is wider than the projection (27) and capable of receiving the projection. The needle shield (46) also includes an inner extension portion (52) projecting proximally into the passageway (26) and capable of contacting the hub (34). The inner extension portion (52) is long enough so that when the needle shield (46) is rotated to align the groove (50) and the projection (27), and moved into a proximal direction with respect to the tip so that the projection (27) enters the groove (50), the inner extension pushes against the hub (34) and moves the hub in a proximal direction causing the second cannula (43) to pierce the pierceable barrier.</p> |
