Abstract: A bottom plate includes a first deepest portion at which a length from a first reference straight line to the bottom plate is maximum. The first reference straight line passes through a front end portion of a front lip and a position at which a rear end portion of the bottom plate is contiguous to each of side plates. The first deepest portion is located on a second reference straight line orthogonal to the first reference straight line. A side end portion of each of the side plates is provided with a recessed portion. The recessed portion includes a second deepest portion at which a length from the first reference straight line to the recessed portion is maximum. The second deepest portion is located on the second reference straight line or located close to the front lip with respect to the second reference straight line.

Abstract: A bottom plate includes a first deepest portion at which a length from a first reference straight line to the bottom plate is maximum. The first reference straight line passes through a front end portion of a front lip and a position at which a rear end portion of the bottom plate is contiguous to each of side plates. The first deepest portion is located on a second reference straight line orthogonal to the first reference straight line. A side end portion of each of the side plates is provided with a recessed portion. The recessed portion includes a second deepest portion at which a length from the first reference straight line to the recessed portion is maximum. The second deepest portion is located on the second reference straight line or located close to the front lip with respect to the second reference straight line.

Abstract: A proximal portion of a first link is pivotally supported by a rear end portion of a frame. A second support shaft is provided in a distal portion of the first link. A first cylinder and a second link to which a counterweight is connected are supported by the second support shaft. A second cylinder is connected to the second link. Through pivoting of the second link by the second cylinder, the counterweight is selectively raised and lowered between a mounting position defined on the frame and a separating position above the mounting position. Through pivoting of the first link by the first cylinder, the counterweight moves between the separating position and the ground surface.

Abstract: A spherical slide bearing has an outer ring and an inner ring slidably retained within the outer ring. A pin having a grease supply flow path extending through an interior thereof to open in an outer peripheral surface thereof is inserted into the inner ring so that the pin is circumferentially slidable, with the inner ring being equipped with a communication flow path establishing communication between a gap defined between the inner ring and the pin and a gap defined between the inner ring and the outer ring. The inlet port of the communication flow path is provided at a position where grease having flown out of an outlet port of the grease supply flow path flows after having flown through the gap between the pin and the inner ring substantially through the entire length in the axial direction of the pin.

Abstract: A spherical slide bearing has an outer ring and an inner ring slidably retained within the outer ring. A pin having a grease supply flow path extending through an interior thereof to open in an outer peripheral surface thereof is inserted into the inner ring so that the pin is circumferentially slidable, with the inner ring being equipped with a communication flow path establishing communication between a gap defined between the inner ring and the pin and a gap defined between the inner ring and the outer ring. The inlet port of the communication flow path is provided at a position where grease having flown out of an outlet port of the grease supply flow path flows after having flown through the gap between the pin and the inner ring substantially through the entire length in the axial direction of the pin.

Abstract: A proximal portion of a first link is pivotally supported by a rear end portion of a frame. A second support shaft is provided in a distal portion of the first link. A first cylinder and a second link to which a counterweight is connected are supported by the second support shaft. A second cylinder is connected to the second link. Through pivoting of the second link by the second cylinder, the counterweight is selectively raised and lowered between a mounting position defined on the frame and a separating position above the mounting position. Through pivoting of the first link by the first cylinder, the counterweight moves between the separating position and the ground surface.