Device for excavating an elongated depression in soil

An excavating device comprising:

• conical milling tools (9, 10) each having a longitudinal center axis (RA);
• at least one motor (7, 8) rotatingly driving said milling tools (9, 10) about said longitudinal center axis (RA);
• said milling tools (9, 10) each having a mantle surface (11, 12);
• said mantle surfaces (11, 12) positioned at one circumferential point adjacent to one another at a minimum spacing defining a working play (15) between said milling tools (9, 10) such that said mantle surfaces (11, 12) form a continuous working plane (AE);
• said longitudinal center axes (RA) of said milling tool (9, 10) angularly (.gamma.) positioned relative to one another and to a vertical axis (VA) extending between said milling tools (9, 10);
• each one of said longitudinal center axes (RA) positioned at an angle of between 50.degree. and 70.degree. to said vertical axis (VA);
• each one of said longitudinal center axes (RA) positioned at an angle (.alpha.) of <90.degree. relative to an advancing direction of said excavating device.