Abstract: A harrowing device for harrowing a ground surface includes a haulable frame. A plurality of blade holders are secured to the frame, and extend downward from the frame. The blade holder has a cavity, a pair of holes, a pair of inclined interior face in the cavity. The inclined interior faces are arranged so as to become close to each other the further away from the holes. A plurality of blades are fitted to the blade holder, each blade having a shank inserted into the cavity and a blade portion for harrowing the ground. The shank has a pair of holes corresponding to the holes of the blade holder, and a protrusion for contacting the inclined interior faces. A pin is inserted into the holes of the blade holder and the shank to pivotably support the blade.

Abstract: There is provided a cultivator blade supporting structure including at least one cultivator blade having a shank and a blade portion, at least one blade holder having a cavity for removably receiving the shank of the cultivator blade, and a rotational driving shaft to which the blade holder is fixed, wherein at least a part of the cavity is defined by first confronting oppositely inclined interior surfaces and second confronting oppositely inclined interior surfaces which have a different inclination angle from the first inclined interior surfaces, so that contact portions of the shank are wedged between and into the first and second inclined interior surfaces when the rotational shaft rotates to cultivate the ground.

Abstract: There is provided a cultivator blade supporting structure. The structure comprises at least one cultivator blade comprising a shank and a blade portion; at least one blade holder having a hollow sleeve for removably receiving the shank of the cultivator blade; and a rotational driving shaft to which the blade holder is fixed, wherein at least a part of the sleeve for receiving the shank of the cultivator blade comprises confronting oppositely inclined interior faces between which the shank is wedged when the cultivator blade is rotated to cultivate the ground.