METHOD AND APPARATUS FOR DEPLOYING A MEMORY WORKING TIP MEMBER

摘要

A wire loop (46) is carried at the distal end of a plunger (44 or 120) which, in turn, is telescoped inside a tubular chassis (40, 42). The proximate end of the plunger (44 or 120) projects from the tubular chassis (40, 42) and is connected to the end of a looped spring handle (60 or 60') by means of which the plunger (44 or 120) can be reciprocated. At the distal end, a nose cone (52) is fitted in the tubular chassis (40, 42) and carries a guide conduit or tip (56) through which the wire loop (46) can be projected or retracted by corresponding movement of the plunger (40 or 120). The wire loop (46) is preformed to a desired shape and curvature and is formed of a material having memory characteristics such that it will return to the predetermined, precurved shape when it is allowed to relax by projection from the guide tip (56). Such loop (46) is capable of being forced to a straightened, compressed condition by retraction into the tip (56), which is achieved by manually withdrawing the plunger (44 or 120) by operation of the handle (60 or 60'). The handle (60 or 60') can be provided with a spring latch (68, 70, 72) to retain the plunger (44 or 120) in a proximally slid condition with the wire loop (46) protruding, against the normal biasing force tending to retract the plunger (44 or 120) and wire loop (46).