Supporting chassis for working machine, with central frame and side-members

Supporting chassis for a working machine, comprising:

• a transversely extending central frame including indentations positioned on opposite sides of a longitudinal middle plane thereof, said indentations having a general concavity extending in a transverse direction away from said middle plane, and two transverse arms which border each said indentation;
• each arm being formed at least partially by a first plate which defines one said indentation and a cross-plate having opposite ends and positioned in a substantially vertical plane, each cross-plate being formed by a central plate assembled with said first plate and at least one end plate, each end plate being welded at an inner edge thereof to said respective central plate, and each arm having a prism-like configuration substantially dihedron in shape;
• and
• two longitudinal side-members placed on opposite sides of and substantially parallel to said middle plane, and the ends of each cross-plate defining indentations which form welding areas where the central frame is secured by welding to the side-members such that said arms are secured to the side members by welding an outermost edge of each end plate to a respective side-member, and said prism-like configuration having an arris which is situated close to said welding areas.