US PATENT SUBCLASS 166 / 128
.~.~.~ Passage controllable by movement of central chamber

Current as of: June, 1999
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166 /   HD   WELLS

179  DF  PACKERS OR PLUGS {17}
118  DF  .~ With expanding anchor {12}
126  DF  .~.~ With controllable passage between central chamber and space below packer {2}
128.~.~.~ Passage controllable by movement of central chamber

DEFINITION

Classification: 166/128

(under subclass 126) Devices in which the valve, closure or changeable restriction controlling the passage is opened, closed or held in position or freed for movement because the central chamber is moved.

SEE OR SEARCH THIS CLASS, SUBCLASS:

127, for devices as defined in this subclass in which there are spaced packer blocking means.