Patent ID: 8608410

Claim:
An apparatus for digging a curvilinear and steeply extending slit and slot hole-shaped excavation when constructing an underground filling wall and stratum structure, the apparatus comprising: a supporting framework means disposed over the ground to produce the hole along a hole line; an elongate, longitudinally displaceable, curvilinear hole-forming means adapted to be disposed in working positions and extended into the ground from the framework means up to a predetermined depth in an advancing direction to excavate, form and support side walls of excavated curved sections of the hole being formed along the length of the line, and to be displaced out of the hole, the forming means comprising: a curvilinear hole-forming motive frame means for supporting components of the forming means, that is capable of being curved and has a front, in relation to the advancing direction, end portion oriented in the advancing direction, and the other rear end portion which being supported and guided by the framework means for movement in the directions; a cutter means for making excavated curvilinear sections of the hole,_the cutter means being supported from ahead on a front end of the front portion and defining at least a substantially horizontal cutting front against an oriented in the advancing direction facial wall of the front hole section, wherein the cutting front being ahead of and perpendicular to the front end portion; wherein the cutter means has the ability of modifying the line by causing the cutting front and the working facial wall to pivot about a horizontal axis, the axis crossing a central longitudinal axis of the front end portion, relative to a portion of the motive means that being adjacent to the front end portion; and wherein the cutter means has the ability to pivot relative to the adjacent portion; and wherein the forming means comprises activating drive means engaged between the cutter means and the front end portion so that operating the activating drive means causes the cutter means and the front end portion to pivot relative to the adjacent portion of the motive means.