Abstract: An agricultural machine including a fixed mast secured to a frame body so as to be projected from a front end portion of the frame body, a movable mast which is pivotably mounted to the fixed mast so as to be arcuately movable in an agricultural working direction relatively to the fixed mast and has a mount portion to which a top link of a tractor is mounted, and a mode selecting mechanism provided between the movable mast and the fixed mast for changing and fixing a positional relationship between the movable mast and the fixed mast interlockingly with a lifting operation of the agricultural machine to thereby freely change a penetrating angle of the agricultural machine into the soil.

Abstract: A coulter adjusting device for use in a reversible plowing machine having a non-reversible mast frame, a bottom frame secured to the non-reversible mast frame in such a manner as to be rotatable or reversible relative to the non-reversible mast frame, a rotatable shaft for rotating or reversing the bottom frame, plural pairs of bottoms fixed to the bottom frame such that each pair of bottoms is secured to upper and lower sides of the bottom frame respectively, and coulters provided in correspondence with each pair of bottoms, at least one of the coulters being secured to the non-reversible mast frame, includes an adjusting mechanism the position of the coulter secured to the non-reversible mast frame by inclining the coulter on a plane perpendicular to a plowing direction by an angle corresponding to the plowing depth, or by moving the coulter in the plowing width direction by an amount corresponding to the tread of a tractor interlockingly with a reversing operation of the bottom frame.