| 摘要 |
PROBLEM TO BE SOLVED: To detect that a telescopic boom 8 swivels to boom retracting positions Bf, Br set at a minute swiveling angle, by divided ring type rotating position detecting means. SOLUTION: The boom swiveling position detecting device is composed of a swiveling position detecting means equipped with a conductive ring member 18 arranged with a plurality of conductors T1, T2, etc., across insulation zones s1, s3 of predetermined width S, and a contacting element 19 rotating interlocking with the swiveling of the telescopic boom 8 while slidably contacting with the conductive ring member 18; and a signal output means 20 receiving detection signals L1, L2, etc., from the swiveling position detecting means and outputting boom retracting position detection signals LBf, LBr. The contacting width Sa of the contacting element 19 is set to be slightly wider than the width S of the insulation zones s1, s3 of the conductive ring member 18, and the positions of the insulation zones s1. s3 are set to positions corresponding to the boom retracting position Bf, Br. The signal output means 20 outputs the boom retracting position detection signals LBf, LBr when the contacting element 19 simultaneously contacts with the conductors T1, T4 on both sides across the insulation zones s1, s3 of the conductive ring member 18. COPYRIGHT: (C)2009,JPO&INPIT
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