| 摘要 |
A vibrating screed for striking off, float finishing and vibrating plastic concrete in a single pass, without being supported upon forms. A rigid, buoyant pan which floats and supports the screed comprises a generally planar surface portion in contact with the plastic concrete and a terminal portion coupled to an associated blade assembly. The blade assembly includes a central L-bracket having a lower horizontal portion substantially parallel with the pan, which terminates in a leading edge adapted to first contact and strike-off unfinished concrete. An associated face plate includes a central portion adapted to be rigidly fastened to the pan terminal portion with the L-bracket substantially sandwiched therebetween. The face plate comprises a downwardly angled guard member which defines a flotation volume between itself and the lower L-bracket, and an upper, diverging wing portion which prevents the accumulation of stricken-off concrete interiorly of the pan. A plurality of spaced apart pneumatic vibrators responsive to external HP air vigorously vibrate the screed pan. A pair of handles pivotally associated with the frame facilitate screed manipulation by a pair of workmen who pull the screed toward them while they are walking backwards. Pan flotation in cooperation with the blade configuration enables the entire apparatus to float upon wet concrete. When the handles are suitably rotated with respect to the frame (i.e. the center of gravity is aligned with the screed body), the entire screed may assume a floating stable and erect position. |
