| 摘要 |
A bull float for working and finishing concrete and the like is provided. The bull float includes a blade. The blade has a first working surface for contacting the work to be troweled. The first working surface has a leading edge and a trailing edge. The blade also has a leading edge member disposed at the leading edge and carries a second working surface disposed at an angle to the first working surface. The blade further includes a trailing edge member disposed at the trailing edge and carries a third working surface disposed at an angle to the first working surface. The bull float includes a planar metal sheet having a front edge and a rear edge, and having its mid area bowed outwardly relative to the working surface. The front and rear edge of the sheet are secured at points fixed with respect to the leading edge and the trailing edge. The sheet exerts uniform opposing bias forces to the leading edge and to the trailing edge of the blade to counteract residual compressive stresses developed on the first working surface during use of the float. |
