| 摘要 |
PROBLEM TO BE SOLVED: To provide a trap door capable of performing full closing and full opening required by avoiding crashing to ground surface, stopper or the like at the time of opening or closing, thereby eliminating unpleasant crashing noise, avoiding decrease in operating life due to crashing, and additionally eliminating failure in full opening or full closing. SOLUTION: This balanced-lever lift type gate door 1 is equipped with supports 2 and 3, arm means 6 and 7 supported in a freely rotatable manner in R direction by the supports 2 and 3 respectively at ends 4 and 5, a door 10 attached to other ends 8 and 9 of arm means 6 and 7 respectively, automatic arm rotating means 13 for automatically performing the rotation of the arm means 6 and 7, control means 14 for controlling the rotation of arm means 6 and 7 by the automatic arm rotation means 13, and detecting means 16 for detecting the speed of rotation of the arms 6 and 7. The automatic arm rotation means 13 has an electric motor 67, and the control means 14 controls the operation of an electric motor 67 based on the results of detection from detection means 16. |
