Concrete trowel

A concrete trowel comprising:

• a frame;
• a drive assembly mounted on the frame and including a drive shaft;
• a rotor including a plurality of blades, the rotor rotatably operably coupled to the drive assembly for rotating about a rotational axis;
• and
• a blade pitch adjustment assembly configured to adjust a pitch of each of the plurality of blades, the blade pitch adjustment assembly including
• a yoke configured to move relative to the rotor between a first position in which each of the plurality of blades is in in a first orientation and a second position in which each of the plurality of blades is in a second orientation;
• an eddy drive assembly driven by the drive shaft, the eddy drive assembly configured to move the yoke from the first position to the second position;
• and
• a control valve assembly configured to be movable between a closed position and an open position,
• wherein when the control valve assembly is in the closed position, the eddy drive assembly is not actuatable and thus the yoke is prevented from moving from the first position to the second position, and
• wherein when the control valve assembly is in the open position, the eddy drive assembly is actuatable and thus the yoke is movable from the first position to the second position to thereby move each of the plurality of blades from the first orientation to the second orientation.

A concrete trowel comprising:

• a frame;
• a drive assembly mounted on the frame and including a drive shaft;
• a rotor including a plurality of blades, the rotor rotatably operably coupled to the drive assembly for rotating about a rotational axis;
• and
• a blade pitch adjustment assembly configured to adjust a pitch of each of the plurality of blades, the blade pitch adjustment assembly including
• a yoke configured to move relative to the rotor between a first position in which each of the plurality of blades is in in a first orientation and a second position in which each of the plurality of blades is in a second orientation,
• a drive plate coupled to the drive shaft for rotation therewith and formed from a magnetically permeable or conductive metal material, and
• a driven rotor movable relative to the drive plate and including a support substrate and at least one magnetic element,
• wherein rotation of the drive plate by the drive shaft causes rotation of the driven rotor via an eddy current at the at least one magnetic element, and
• wherein rotation of the driven rotor causes the yoke to move from the first position to the second position and thereby to move each of the plurality of blades from the first orientation to the second orientation.