US PATENT SUBCLASS 166 / 77.4
.~.~ Piston and cylinder

Current as of: June, 1999
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166 /   HD   WELLS

75.11  DF  ABOVE GROUND APPARATUS {25}
77.1  DF  .~ Moving tubing or cable into an existing well {2}
77.4.~.~ Piston and cylinder

DEFINITION

Classification: 166/77.4

Piston and cylinder:

(under subclass 77.1) Moved tubing wherein the thin-walled pipe is pushed by an assembly including a generally tubular-shaped member confining a movable mass and driven by fluid pressure.

(1) Note. Patents properly classifiable here must include specific piston and cylinder structure connections; i.e., claims properly classified under subclasses 77.2 and 77.3 are not classified here.