Abstract: A high performance twin engine riding trowel for finishing concrete. A rigid frame mounts two downwardly projecting rotors that counter-rotate simultaneously. A guard cage mounted to the frame prevents inadvertent contact between the rotors and foreign objects. An operator sits in a seat mounted to the frame and steers the rotors with a pair of primary control levers that tilt the rotors to generate steering forces. The longitudinal pitch of the blades on each rotor is adjustable. Throttle controls are interconnected to synchronize the engines at low throttle and higher speeds. Illumination may be provided by lights mounted on the frame. Each engine slidably mounts a generally parallelepiped block attached to the frame. The engines counter-rotate while establishing generally coaxial, horizontal axes of rotation. Each engine drives a rotor through a belt system attached to a driveshaft.

Abstract: A guard clearance system for motorized riding trowels adapted to allow finishing of a slab surface immediately adjacent an obstacle. The system comprises a movable arc of trowel guard cage displaceably coupled to an end of the trowel guard cage and spaced apart buffer wheels mounted to the cage. The arc is displaceable between a deployed position generally aligned with a lower ring of the cage and a retracted position. When retracted an unguarded segment of the trowel rotor sweep is established, allowing the finishing blades to be deployed immediately adjacent a wall or other obstacle. A displaceable coupling for moving the arc between the deployed position and the retracted position extends from the cage to the arc. In a mechanical embodiment the displaceable coupling is a pair of slidably adjustable brackets extending from the arc to the cage. The displaceable coupling may comprise electromechanical elements for displacing the arc between deployed and retracted positions.