PURPOSE: To simplify the structure of a moving unit so as to be reduced in its weight by rotatably ad successively inserting the boss part of each swing unit into a spindle via thrust bearings, and setting the boss coaxially and integrally to the spindle by means of fixing members fixed to both ends of the spindle. ;CONSTITUTION: Each of swing units 3a-3e is integrated to each other centering around a spindle 10, and it is individually rotatable around the spindle 10 by thrust bearings 9 intervened therebetween in a moving unit 4. Each thrust bearing 9 is positioned in such a manner that it is fitted from an upper surface inner side step part to a lower surface side step part between respective boss parts. Further, each member is prevented from occurrence of core slip even though each boss part is rotated, and friction between the spindle 10 and the thrust bearing 9 is prevented to occur even though each swing unit is rotated because the thrust beagings 9 on an upper end and a lower side are respectively fixed to upward/downward supporting plates 35a, 35b so that each of swing units 3a-3e is smoothly rotated.;COPYRIGHT: (C)1995,JPO
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