Patent ID: 7338081

Claim:
A truck frame for a construction machine, including a center frame for mounting an upper structure, right and left side frames located on the right and left sides of said center frame and extended toward front and rear ends, fore and hind legs provided on each side of said center frame to connect said right and left side frames, characterized in that: said center frame includes a top plate having a round girth member to support thereon said upper structure rotatably through a swing ring, a bottom plate located under said top plate in face to face relation, and right and left side plates attached to right and left sides of said top and bottom plates across said round girth member; each one of said right and left side plates is composed of a fore leg joint surface and a hind leg joint surface in front and rear portions thereof for joining thereto inner joint portions of said fore and hind legs, respectively, said fore leg joint surface being extended in a longitudinal direction and in parallel relation with said side frame, and said hind leg joint surface being disposed angularly relative to said fore leg joint surface and extended in an oblique direction to turn away from said side frame in a rearward direction; each one of said fore legs is composed of said inner joint portion joined with said fore leg joint surface of said center frame by welding, an outer joint portion joined with one of said side frames by welding, and an intermediate tubular portion provided between said inner joint portion on the side of said center frame and said outer joint portion on the side of said side frame; each one of said hind legs is composed of said inner joint portion joined with said hind leg joint surface of said center frame by welding, an outer joint portion joined with one of said side frames by welding, and an intermediate tubular portion provided between said inner joint portion on the side of said center frame and said outer joint portion on the side of said side frame; each of said inner and outer joint portions being formed in the shape of a flare tube being spread gradually from said intermediate tubular portion toward a joining end, respectively; and said joining ends of each of said joint portions being an open end of a substantially rectangular shape, respectively.