(under subclass 24) Subject matter in which a sensed characteristic of drilling fluid circulation controls a power operated means to modify the boring operation.
SEE OR SEARCH THIS CLASS, SUBCLASS:
25, for automatic control of fluid pressure below ground.
SEE OR SEARCH CLASS
173, Tool Driving or Impacting,
3, for automatic control of a power operated tool driving or impacting means in response to a condition of a cleansing means.
