Work machine

Abstract

A work machine is capable of rotating an attachment while appropriately supporting a load applied to the attachment. The work machine has a hydraulic cylinder attached to a body side surface of an arm and a first link rod extending along a back side surface of the arm. A second link rod is rotatably supported via a first pin extending in the width direction of a front working device, and has one end projecting toward the back side surface of the arm and the other end projecting toward the body side surface thereof. One end of the first link rod is rotatably connected to the attachment. One end of the second link rod is rotatably connected to the other end of the first link rod, and the other end thereof is rotatably connected to a distal end of a cylinder rod of the hydraulic cylinder via a third pin.

1 . A work machine comprising:
 an undercarriage;   an upperstructure supported on the undercarriage so as to turn thereon;   a front working device including a boom supported on the upperstructure so as to be raised and lowered, an arm rotatably supported at a distal end of the boom, and an attachment rotatably supported at a distal end of the arm,   wherein   the arm includes:
 a pair of side surfaces that faces each other in a width direction of the front working device; and 
 a body side surface and a back side surface that face each other in a direction perpendicular to the width direction of the front working device, each of which is connected to ends of the pair of side surfaces, 
   the front working device includes:
 a hydraulic cylinder that is attached to the body side surface of the arm, and is supplied with and discharges hydraulic oil to extend and contract; and 
 a link mechanism configured to cause the attachment to dump when the hydraulic cylinder extends and cause the attachment to crowd when the hydraulic cylinder contracts, 
   the linkage mechanism includes:   a first link rod that extends along the back side surface of the arm;   a second link rod that is rotatably supported on the side surfaces of the arm via a first pin extending in the width direction of the front working device, the second link rod having one end which projects toward the back side surface of the arm and the other end which projects toward the body side surface of the arm,   one end of the first link rod is rotatably connected to the attachment,   the one end of the second link rod is rotatably connected to the other end of the first link rod via a second pin extending in the width direction of the front working device, and   the other end of the second link rod is rotatably connected to a distal end of a cylinder rod of the hydraulic cylinder via a third pin extending in the width direction of the front working device.   
     
     
         2 . The work machine according to  claim 1 , wherein
 a distance between the first pin and the third pin is equal to or more than a distance between the first pin and the second pin.   
     
     
         3 . The work machine according to  claim 1 , further comprising a stopper that is fixed to the back side surface of the arm, wherein the first link rod abuts the stopper before the hydraulic cylinder extends to a maximum so as to prevent the attachment from further dumping.