(under subclass 2) Apparatus in which the sensing means senses the condition of (1) a specific modification of the tool drive which is for the purpose of removing unwanted material from the work face being operated on by the tool or (2) structure combined with the tool drive which functions to remove unwanted material from the work face being operated upon by the tool.
SEE OR SEARCH CLASS
175, Boring or Penetrating the Earth,
38, for automatic control of an earth boring means in response to drilling fluid circulation.
