Patent ID: 7690441

Claim:
A blade device mountable on various working machines, wherein a blade includes a central front face, and left and right end front faces continuously provided through coupling front faces which are bent and continuously provided on left and right ends of the blade, a lower end of the central front face has a blade width W 1 which intersects orthogonally with an excavation direction and extends laterally, and the central front face is further provided at the lower end of the central front face with a first cutter, the coupling front faces and the end front faces are provided at lower ends of the coupling front face and lower ends of the end front faces, respectively, with second and third cutters, a cross line between each of the coupling front faces and each of the end front faces and an intersection of each tip of the second and third cutters are located rearward of a tip of the first cutter as viewed from above, respective front faces of the central front face, the coupling front faces and the end front faces are concavely curved faces which are continuous from upper ends to lower ends, and when the blade width of the central front face is defined as W 1 , a distance between an extension of the first cutter and the intersection of each tip of the second and third cutters is defined as Wt, and a backward-bending angle between the tip of the first cutter and the second cutter is defined as δ, the distance Wt and the backward-bending angle δ simultaneously satisfy following expressions (I) and (II): Wt> 0.65×( W 1/10) (I) 14°<δ<30° (II).