| 摘要 |
PROBLEM TO BE SOLVED: To provide an angle detector, capable of prolonging the life time of a vibrating motor, provided to reduce hysteresis and the rotational torque of the angle detector. SOLUTION: In this angle detector provided with a potentiometer 22 provided in a casing 21 forming an outer shell, and an oscillator 24 attached to an shaft 23 of the potentiometer 22, and for detecting a ground angle of an angle to a horizontal face, the vibration motor 25 is provided inside the casing 21; the vibration motor 25 is driven only during operations of a tower turning-up and -down winch 8 and a jib turning-up and -down winch 9 for turning up and down a tower boom 2 and a tower jib 3, that is, only when the hysteresis in the angle detector is required to be removed; and the life time of the vibration motor 25 is prolonged thereby. COPYRIGHT: (C)2005,JPO&NCIPI
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