(under subclass 29) Apparatus in which the advance causing means comprises a device having feet or plate type anchors which alternately engage and disengage the ground or the sidewalls of a tunnel to cause the apparatus to move forward.
SEE OR SEARCH CLASS
180, Motor Vehicles,
8.1+, for a stepper type motor driven vehicle.
254, Implements or Apparatus for Applying Pushing or Pulling Force,
134.6, for a step by step type tractor for pulling cable in
wire or stand placing. 305, Wheel Substitutes for Land Vehicles,
1+, for a stepper type wheel substitute.
405, Hydraulic and Earth Engineering,
299+, for a walking roof support for use in a mine, and which may be utilized for advancing a mining machine.
