| 摘要 |
PROBLEM TO BE SOLVED: To surely restrict the swing angle of excavating arms by eliminating the formation of a recessed part in the surfaces of a head body 1 and the excavating arms 40 on which they are rubbed to prevent the inclusion of foreign matters from occurring. SOLUTION: To form an excavating head 50, the excavating arms 40 are connected to the head body 1 swingably around horizontal shaft 20 at the front of the head body 1 connectable to an excavation rod 52. (a) A stopper 22 for restricting the swing by coming into contact with the side edge 40b of the excavating arm 40 during small-diameter excavating and (b) stoppers 26, 28 for restricting the swing by coming into contact with the side edge 40b of the excavating arm 40 during large-diameter excavating are attached to the head body 1. The head body 1, the horizontal shaft 20, and the excavating arms 40 are installed to be deformed so that the end rear surfaces of both excavating arms 40 are separated from the front of the head body 1 (a) when the excavating arms 40 are temporarily reversely rotated at the swing angle during the small-diameter excavation, and the rear surfaces of the excavating arms 40 are deformable to extend over the stopper 22", and (b) then normally rotated to be brought into the large-diameter excavating state. COPYRIGHT: (C)2009,JPO&INPIT
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