| 摘要 |
PROBLEM TO BE SOLVED: To provide a passenger conveyor capable of efficiently calling attention to a user performing any abnormal use of the conveyor without generating any unnecessary noise. SOLUTION: A directive loudspeaker 5 is arranged on an upper floor. The warning sound with the ultrasonic wave being modulated as the carrier wave is emitted toward a lower floor, and the warning sound is audible only in an audible zone 6. The audible zone 6 covers a prohibition zone outside a parapet 2 so that the warning sound can be heard only by a user 8 leaning out from the parapet 2. COPYRIGHT: (C)2007,JPO&INPIT
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