Abstract: A high performance, three engine, three rotor riding trowel for finishing concrete. A rigid, generally triangular frame mounts three downwardly projecting, bladed rotors that frictionally engage the concrete surface therebelow. The rotors on opposite sides of the operator (i.e., to the left or right) rotate in opposite directions, and they are tilted in coincident pivot planes that are parallel with the frame rear. The front rotor is titled in a plane that is perpendicular to the pivoting plane of the other two rotors. Tilting of the rotors with double acting hydraulic cylinders effectuates steering of the apparatus. Joy sticks enable the operator to hand control the trowel with minimal physical exertion. A unique hydraulic powered linkage generates steering forces by tilting the rotors in response to electrical signals. The gearboxes are interchangeable and mounted to tiltable, steering boxes secured to the frame. Each rotor establishes a generally vertical axis of rotation.

Abstract: In a powered riding trowel of the type having at least two adjacent rotor assemblies wherein said rotor assemblies include rotors which are counter rotating relative to one another, and wherein the rotors circumscribe a circular path during operation, the rotor assemblies being affixed to a framework such that the paths circumscribed by the rotors are spaced apart so that tangential forces developed along the circumference of the respective paths do not interact to reinforce one another.