To improve the digging work efficiency and performance and improve running cost.
In this free cross section excavator which is provided with an arm arranged on a base and a pulse generator 22 which applies high voltage pulses to a pair of electrodes P that digging heads 30a, 30b provided at a tip of the arm have and electrically, crushes an object to be crushed, the pulse generator 22 is attached to the arm (in particular, a tip part thereof). The arm may be provided on an upper vehicle body 2 on a lower running body 1. A converter 21 converting an alternating voltage into a high direct current voltage is provided on the opposite side to the arm. A plurality of digging heads are provided, and they are attached in such a way that they can move in forward, backward, vertical, right, and left directions mutually and independently or can oscillate to the right and left and can turn up or down vertically. The digging head is provided with a head housing 53 which forms a recessed shape and holds a solution around the pair of electrodes P, a partition plate which separates an inner space into a front chamber and a rear chamber, a through passage, and a solution recovery means which pours or recovers the solution between the front chamber and the rear chamber at the time of crushing or upon completion of crushing.
HANAMOTO TADAYUKI
KATO YUTAKA
SHIAKU MASANAGA
INO TAKAO
MASUTANI YOSHINOBU
