Further, because of the pair of levers 14, 14 having independent both ends, the spring forces at both ends are equalized, and so the shutter plate 15 can be moved in such a manner as to automatically eliminate the formation of {HEAD ~ clearance} in {TAIL ~ the transverse direction} 
in
Further , because of the pair of levers 14 , 14 having independent both ends , the spring forces at both ends are equalized , and so the shutter plate 15 can be moved in such a manner as to automatically eliminate the formation of { HEAD ~ clearance } in { TAIL ~ the transverse direction }
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