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 laser controlled automatic grade control system for finishing plastic concrete mounts the finishing tool behind the support towers to resist furrowing. The system functions with a variety of elongated, multi-section concrete finishing tools such as triangular truss screeds or the like, all of which can be quick connected or disconnected from the tower system. Skis that support the device facilitate sliding, winch-driven movement over and through plastic concrete. Spaced apart, vertically upwardly extending towers support the device along the length of the finishing tool. The towers are cylinder-adjustable in length. Cylinder extension and retraction are governed by a sensor-controlled system that is laser operated. The sensors respond to a preestablished laser beacon to control finishing tool elevation as the device traverses the pour in response to its winches.

Abstract: A self-propelled, dual motor, variable width riding trowel for finishing a concrete surface. The riding trowel comprises a frame mounting a seat for an operator and controls accessible by the operator for steering and controlling the trowel. Adjustable subframe blocks mount a pair of motors, each driving a bladed rotor for frictionally contacting the concrete surface and supporting the frame. Displaceable gearboxes, pivotally mounted to the subframe, transfer rotation from each motor to its rotor. The motors are interlinked by an extensible driveshaft extending between the gearboxes that synchronizes the rotors. Lever arms disposed beneath the frame tilt the gearboxes and rotors in response to the controls for steering the trowel. An extensible guard cage, mounted to the frame, prevents inadvertent contact between the rotors and foreign objects. The trowel may be expanded to receive finishing pans on the blades of the rotors. Expansion of the trowel requires displacement of several components.

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.