| 摘要 |
A portable vibrating screed includes a driven, vibratory rotatable shaft assembly mounted on an elongated frame equipped with means for screeding concrete. The shaft assembly includes a plurality of bearing assemblies spaced along the length of the shaft. Each bearing assembly includes a pair of separate bearing elements mounted on the shaft and supported in bearing supports secured to the frame. Failure of any single bearing element allows a companion bearing element in the same assembly to absorb all of the load imposed on such assembly to prevent shutdown and without impairing the needed vibration.
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