20110033235 | CONCRETE FINISHING TROWEL WITH SPEED CONTROL - A concrete finishing trowel includes a frame, a power source supported on the frame and having an output shaft, at least one rotor assembly supported on the frame. Each rotor assembly comprises a driven rotor shaft with a plurality of trowel blades extending outwardly therefrom so as to rest on a surface to be finished and to rotate with said driven rotor shaft to finish a respective circular area. A transmission system operably couples the power source output shaft to the driven rotor shaft of the at least one rotor assembly. The transmission system includes a variable driving pulley operable coupled directly or indirectly to the power source output shaft and including a resiliently deflectable portion that is movable to change the effective drive diameter of the variable driving pulley, and a variable driven pulley operably coupled to the variable driving pulley with a belt. The variable driven pulley in turn is operably coupled directly or indirectly to the driven rotor shaft of the at least one rotor assembly. A rotor speed control system permits an operator to adjust the center-to-center distance between the pulleys, thereby to cause the drive diameter of the variable driven pulley to change resulting in an adjustment of the speed of the driven rotor shaft. | 02-10-2011 |