To obtain a structure of a pivotal connection part in a swing device having a large load bearing capacity and allowing smooth horizontal rotational movement.

In a power shovel including a power shovel mechanism 20 pivotally connected and fitted to a vehicle body 10 to be horizontally rotatable, the structure of the pivotal connection part comprises a body-side pivotal connection part 15 mounted on a front part of the vehicle body 10 and a swing-side pivotal connection part 25 mounted on a base part of the power shovel mechanism 20, which are pivotally connected to each other in a horizontally rotatable manner by the intermediary of a pivotal connection pin 55 extending substantially vertically. A disc-shaped thrust washer 50 is arranged between the body-side pivotal connection part 15 and the swing-side pivotal connection part 25 vertically facing each other. A lubricating spiral groove 53 is formed in a sliding contact face of the thrust washer 50.

COPYRIGHT: (C)2008,JPO&INPIT