Latch for gas lift valve or the like

Claim 1

A latch for securing a gas lift valve or the like in a valve seat which includes a locking shoulder which prevents said latch from being withdrawn after said valve is seated, said latch comprising, in combination: a central core, a latch sleeve slidably mounted on said core for axial movement relative to said core, said sleeve including an enlarged lower portion, a central portion having an outside diameter less than the outside diameter of said enlarged lower portion and an enlarged upper portion having an outside diameter greater than the outside diameter of said central portion, upper and lower stop means for limiting the axial movement of said sleeve relative to said core between a first top position and a second bottom position, and a collet slidably mounted on said sleeve for axial movement relative to said sleeve, said collet comprising a collar member surrounding said enlarged upper portion of said sleeve and a plurality of spring finger members projecting downwardly from said collar member, each of said finger members including an outwardly projecting nose portion at the end thereof, said collet being capable of axial movement relative to said sleeve from a first top position in which the ends of said finger members are on the level of said central portion of said sleeve to a second central position in which the ends of said finger members are on the level of said enlarged lower portion of said sleeve to a third bottom position in which the ends of said finger members are beneath said enlarged lower portion of said sleeve, whereby: (1) when said sleeve is in its second bottom position and said collet is in its first top position, said finger members can be deflected radially inwardly until said nose portions contact said central portion of said sleeve; (2) when said sleeve is in its second bottom position and said coLlet is in its second central position, said enlarged lower portion of said sleeve prevents inward radial deflection of said finger members; and (3) when said sleeve is in its first top position and said collet is in its third bottom position, said finger members can be deflected radially inwardly as said nose portions portions pass beneath said enlarged lower portion of said sleeve.