Abstract: A mounting structure for a center frame and crawler frames of a base carrier of a construction machine, which can increase durability without complicating the structure is provided. A crawler frame mounting structure for a construction machine includes a center frame configured to rotatably support an upper rotating body, fastening portions for fastening the center frame to crawler frames on right and left sides by front and rear leg portions, and end plates having widths wider than the width between attachment positions of a pair of vertical plates. The end plates including tie bolt holes formed on both right and left ends are welded.

Abstract: A mounting structure for a center frame and crawler frames of a base carrier of a construction machine, which can increase durability without complicating the structure is provided. A crawler frame mounting structure for a construction machine includes a center frame configured to rotatably support an upper rotating body, fastening portions for fastening the center frame to crawler frames on right and left sides by front and rear leg portions, and end plates having widths wider than the width between attachment positions of a pair of vertical plates. The end plates including tie bolt holes formed on both right and left ends are welded.

Abstract: The invention provides a working machine of a hydraulic backhoe in which the blade tip force can be increased over a wide range of operations, which has a great blade tip force at the start of excavation, and which can increase working efficiency by avoiding obstacles. For these purposes, a second link pivotally connected to third fulcrums (6, 13) provided in common at a leading end of an arm cylinder (4) and one end of a first link (10) and to a second fulcrum (12) of an arm (2) is a hydraulic correction cylinder (11). A working hydraulic circuit for the arm cylinder (4) and the correction cylinder (11) may constitute a series circuit having a circuit (24) connecting a head side oil chamber (20) of the arm cylinder (4) to a bottom side oil chamber (23) of the correction cylinder (11).