| 摘要 |
A trocar assembly comprising an elongate trocar obturator having a piercing tip at its front end, an elongate trocar tube in which the obturator is housed, and a tubular protective shield mounted concentrically around the obturator between a normally extended position in which the obturator tip is covered and a retracted position in which the obturator tip is exposed. Further included is a spring acting on the protective shield, whereby the shield is forced to the retracted position to expose the piercing tip when the trocar is being inserted through the wall of a body cavity and is biased by the spring to the extended position to shield the piercing tip once the trocar has pierced the wall. A protrusion extends radially from the shield. A leaf spring element has one end anchored relative to the obturator and a second end biased to contact the protrusion in a manner preventing movement of the shield from the extended position toward the retracted position when the element is in contact with the protrusion. A trigger, coupled to the leaf spring member is shiftable between a lock position and a release position. When the trigger is in the lock position, the shield can not be moved from the extended position. When it is in the release position, the shield can travel to the retracted position. When it moves to the retracted position, it disengages the trigger so that when the shield returns to the extended position, it locks in place, even through the trigger is in the release position.
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