| 摘要 |
A tandem screed for use with a paving machine for compacting and smoothing asphalt paving composition includes a front screed mounted at the end of a towing arm and a rear screed mounted to the rear of the front screed and laterally extensible with respect thereto. A rear screed hydraulic cylinder is hooked up in series with a tow point hydraulic cylinder such that as the tow point is lowered, the rear screed is lowered with respect to the front screed; and as the tow point is raised, the rear screed is raised with respect to the front screed. The rear screed is thereby maintained at the same elevation as the front screed as the tow point is raised or lowered, thus avoiding bumps and irregularities in the pavement surface. In addition, self-leveling circuitry actuated by the stopping and restarting of the paving machine automatically brings the screeds to a level orientation with respect to the mat as the paving machine is stopped, and returns the screeds to their original angle of attack as the paving machine is restarted. In this manner, bumps in the mat resulting from stopping and restarting the paving machine are eliminated.
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