Abstract: A self-propelled power trowel for finishing a concrete surface is equipped with reversible rotors to allow an operator to reverse the direction of rotation of rotor blades. The trowel includes a rigid frame adapted for operation over a concrete surface, a pair of rotor assemblies having rotor blades tiltably connected to the rigid frame for frictionally contacting the concrete surface and supporting the rigid frame thereabove, a prime mover mounted to the rigid frame and operatively coupled to drive the rotor blades of the rotor assemblies in opposite rotational directions. Synchronous or hydraulic motors are configured for causing, responsive to manual controls, reversal of the direction of rotation of the rotor blades.

Abstract: A self-propelled power trowel for finishing a concrete surface is equipped with reversible rotors to allow an operator to reverse the direction of rotation of rotor blades. The trowel includes a rigid frame adapted for operation over a concrete surface, a pair of rotor assemblies having rotor blades tiltably connected to the rigid frame for frictionally contacting the concrete surface and supporting the rigid frame thereabove, a prime mover mounted to the rigid frame and operatively coupled to drive the rotor blades of the rotor assemblies in opposite rotational directions. Synchronous or hydraulic motors are configured for causing, responsive to manual controls, reversal of the direction of rotation of the rotor blades.

Abstract: A self propelled power trowel for finishing a concrete surface is equipped with reversible rotors to allow an operator to reverse the direction of rotation of rotor blades. The trowel includes a rigid frame adapted for operation over a concrete surface, a pair of rotor assemblies having rotor blades tiltably connected to the rigid frame for frictionally contacting the concrete surface and supporting the rigid frame thereabove, a prime mover mounted to the rigid frame and operatively coupled to drive the rotor blades of the rotor assemblies in opposite rotational directions. Synchronous or hydraulic motors are configured for causing, responsive to manual controls, reversal of the direction of rotation of the rotor blades.

Abstract: A self propelled power trowel for finishing a concrete surface is equipped with reversible rotors to allow an operator to reverse the direction of rotation of rotor blades. The trowel includes a rigid frame adapted for operation over a concrete surface, a pair of rotor assemblies having rotor blades tiltably connected to the rigid frame for frictionally contacting the concrete surface and supporting the rigid frame thereabove, a prime mover mounted to the rigid frame and operatively coupled to drive the rotor blades of the rotor assemblies in opposite rotational directions. Synchronous or hydraulic motors are configured for causing, responsive to manual controls, reversal of the direction of rotation of the rotor blades.

Abstract: A hybrid drive train for a self propelled power trowel includes a frame having a centerline from front to rear, an engine-generator set, a pair of rotors with trowel blades tiltably connected to the frame and positioned to support the frame above a concrete surface being finished, electric motors for driving the rotors, means for tilting each rotor toward and away from the centerline, and means for tilting a rotor fore and aft, parallel to the centerline. A rectifier and inverter in series at the engine-generator output allows engine speed to be regulated by a capacitor bank, and usage of highly efficient brushless AC synchronous motors to drive the rotors. A rechargeable battery may be connected in parallel with the capacitor bank.

Abstract: A hybrid drive train for a self propelled power trowel includes a frame having a centerline from front to rear, an engine-generator set, a pair of rotors with trowel blades tiltably connected to the frame and positioned to support the frame above a concrete surface being finished, electric motors for driving the rotors, means for tilting each rotor toward and away from the centerline, and means for tilting a rotor fore and aft, parallel to the centerline. A rectifier and inverter in series at the engine-generator output allows engine speed to be regulated by a capacitor bank, and usage of highly efficient brushless AC synchronous motors to drive the rotors. A rechargeable battery may be connected in parallel with the capacitor bank.

Abstract: A safety latch telescoping mast system for a portable light tower having a towable trailer having a frame and an engine driven electrical generator and a light assembly for attachment to the uppermost end of a telescoping mast member, which includes a pivotable spring loaded safety latch assembly positioned to remain in a first, cocked, position wherein an idler roller is in rotational engagement with a hoisting cable and the latch is outside the opening in the stationary mast member when the first hoisting cable is under tension, which trips to a second, position wherein the latch passes through the opening in the stationary mast member and engages into a slot in the first telescoping mast member when the tension on the first hoisting cable is relieved.