Patent ID: 7810581

Claim:
A blade apparatus for a work machine, the blade apparatus mounted on various work machines, wherein the blade apparatus comprises: a central front surface portion, and a connecting front surface portion, and end front surface portions, each of which are bent and continuously provided on each of right and left ends of the central front surface portion in succession; the central front surface portion has a blade width whose lower end intersects with a digging direction and extends laterally, and is provided at a further lower end of said lower end with a first cutting edge; the connecting front surface portion is disposed on each of the right and left ends of the central front surface portion, and a second cutting edge provided at a lower end of the connecting front surface portion; the end front surface portion is continuously formed on the connecting front surface portion and is provided at its lower end with a third cutting edge; a cross line between the connecting front surface portion and the end front surface portion and a cross point between blade edges of the second cutting edge and the third cutting edge are located on retreat positions rearward of a blade edge of the first cutting edge as viewed from above; respective front surfaces of the central front surface portion, the connecting front surface portion and the end front surface portion have a central blade portion formed on vertically continuous concave curved surfaces and an end blade portion which is continuously formed on each of right and left ends of the central blade portion through a connection blade portion; and a blade that comprises: a pair of right and left integral castings which include at least all of the connection blade portion and the end blade portions, and a region of right and left connecting side end portion of the central blade portion; a plate portion including at least a main region which excludes the region of right and left connecting side end portion of the central blade portion, and having a connection end surface connected to a connection end surface of the integral casting, and a connection line between the each connecting end surface of the integral casting and the each connecting end surface of the plate portion is located on a vertical straight line as viewed from front, wherein a back surface support member is disposed on a back surface of the plate portions such that the back surface support member and the back surface of the integral casting are flush with respect to each other.