JP2934547B

PURPOSE:To carry out wide access and enough visual inspection through a carrying-in opening of a small caliber from a narrow passage, by mounting a visual instrument on a mobile truck self-propelled on a track having a plurality of joints and having a leg at the tip. CONSTITUTION:An arm 1 becomes a folded state by the flexing function of a plurality of joints 4. The work of the arm 1 can be carried out even in a narrow passage because of lengthening the arm 1 in a straight line state on occasion by the joints 4 of a structure opened in the horizontal direction and inserting it, in the time inserting the arm 1 within a cell 21 from a penetrated opening 26. Both ends of the arm 1 are supported and the deflection and deviation of the long arm 1 are reduced, because of putting a wire lope 3 and vertically standing a supporting leg 2 fitted to the tip of the arm 1 after the insertion. Further, wide access can be carried out by a mobile truck 12 moved on the arm 1 as a guide by a driving mechanism for traveling, and by the turning of a turnable arm 17 fitted to the truck 12 and controlled by a driving device for turning; and enough visual inspection can be carried out by a visual head 16 fitted to the arm 17.