Abstract: Disclosed is a lower track for mounting rubber pads on a track shoe to be attachable and detachable after assembling a steel plate which is adhered with divisionally formed rubber pads as a single unit without additionally perforating coupling through-holes in the track shoe when the rubber pad which forms the lower track and the track shoe which is formed of a metal material are coupled. The lower track of a crawler excavator according to the present invention comprises: first and second rubber pads which are divisionally formed; a first steel plate which supports the bottom surface of the first rubber pad by surrounding the same, and has first hooks formed on the bottom surface thereof and coupling holes formed in a connection stepped-portion.

Abstract: Disclosed is a lower track for mounting rubber pads on a track shoe to be attachable and detachable after assembling a steel plate which is adhered with divisionally formed rubber pads as a single unit without additionally perforating coupling through-holes in the track shoe when the rubber pad which forms the lower track and the track shoe which is formed of a metal material are coupled. The lower track of a crawler excavator according to the present invention comprises: first and second rubber pads which are divisionally formed; a first steel plate which supports the bottom surface of the first rubber pad by surrounding the same, and has first hooks formed on the bottom surface thereof and coupling holes formed in a connection stepped-portion.

Abstract: Disclosed is a control system for controlling flow so as to allow simultaneous usage of a parallel flow path and a tandem flow path thereby reducing loss of pressure inside a control valve, when simultaneously operating work devices having different operating pressures.