| 摘要 |
PROBLEM TO BE SOLVED: To provide a crossing bar breakage preventing device simply constituted to be free from a malfunction. SOLUTION: The device comprises a fixed cylinder 31, a fixed plate 32, a movable plate 33 having a crossing bar holder 34, a link mechanism for displacing a crossing bar when a high load works on the crossing bar, and a locker 35 for constraining the motion of the movable plate 33. A joint part 40 for journaling the movable plate 33 to the fixed plate 32 so as to be turnable in the opposite direction has shaft pins 414, 424, and cylinder shafts 412, 422 as shaft supporting portions for journaling the shaft pins 414, 424 in a disengageable manner. In a state of locking the shaft pins 414, 424 to the cylinder shafts 412, 422, the movable plate 33 is allowed to turn in a predetermined direction using the shafts pins 414, 424 locked to the cylinder shafts 412, 422 as turning axes, while inhibiting the turn of the movable plate 33 in the opposite direction with respect to the predetermined direction. COPYRIGHT: (C)2009,JPO&INPIT
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