In some implementations, an ejection paddle may include a paddle body having an ejection surface and a mounting surface opposite the ejection surface, and a wear region projecting from the ejection surface and extending along a top edge of the paddle body and at least a portion of a first side edge and a second side edge of the paddle body. The paddle body may be recessed relative to the wear region.

A hydromill wheel (5) for excavating a trench in hard rock includes a drum (4) arranged to be rotated about its axis (A, B). The wheel (4) further includes a plurality of single disc cutters (11) mounted on the periphery of the drum (5), the single disc cutter (11) having a rotatable single cutting disc (11) arranged to come in contact with and crush the rock during excavation. The spacing of the projection of at least some of the cutting discs (11) on the drum axis (A, B) is 20% to 70% of the cutting disc diameter.

In some implementations, an ejection paddle may include a paddle body having an ejection surface and a mounting surface opposite the ejection surface, and a wear region projecting from the ejection surface and extending along a top edge of the paddle body and at least a portion of a first side edge and a second side edge of the paddle body. The paddle body may be recessed relative to the wear region.

The disclosure relates to a trench cutter with at least one milling wheel that is rotatably mounted on a bearing plate and has at least one adjustable cutting tool for crushing soil material, wherein the adjustable cutting tool comprises a base body that is movably mounted on the milling wheel and interacts with the bearing plate in such a way that the adjustable cutting tool moves automatically between a folded-in position and a folded-out position as a function of the angle of rotation when the milling wheel is rotated. The adjustable cutting tool can be moved from the folded-out position into the folded-in position via a first guide element that contacts the bearing plate. According to the disclosure, the first guide element is formed integrally with the base body and projects from the base body in the direction of the bearing plate on a side facing the bearing plate.

The method for directionally swaying and resetting harrow teeth of a rolling harrow loader-excavator and the rolling harrow loader-excavator comprising a harrow rotary piece, directional sway and reset harrow teeth, a harrow supporter, a driving mechanism, a feeder mechanism and a body; each directional sway and reset harrow tooth comprises a torsion spring shaft supporting piece, a tooth handle sway limiting piece, a directional sway and reset tooth handle, a directional sway and reset tooth point, a torsion spring tooth handle shaft, a torsion spring and a torsion spring tooth handle shaft retaining piece.