A method for thermal management of a power trowel executable by an on-board logic controller allows operation of the trowel in normal mode in which rotor speed is determined by manual control and in which a sensed temperature of the trowel lies below a high temperature setpoint. In response to the sensed temperature exceeding the high temperature setpoint, the controller switches operation of the power trowel from normal mode to thermal management mode in which a maximum rotor speed achievable by manual control is reduced by the controller in incremental steps to allow the trowel to cool. In response to the sensed temperature reaching a low temperature setpoint, the controller increases rotor speed in incremental steps, and returns operation to normal mode when a desired rotor speed is maintained for sufficient time during which the sensed temperature remains below the low temperature setpoint.

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.

A support structure for a float pan for floating a concrete surface provides an interface between the float pan and a rotating machine. The support structure is characterized by a hub configured for concentric attachment to a rotor, and by trusses that extend radially from the hub, each providing a float pan contact surface and means for attachment to the float pan. Perimetric bracing links the trusses about the perimeter of the support structure. A machine similar to a walk-behind or ride-on trowel but without rotor blades, may incorporate the support structure and operate as a dedicated power flotation machine. Under weight of the machine, the contact surfaces of the trusses conform the float pan to a desired shape or radius of curvature for optimizing a flotation process.

A mounting adapter for mounting a surface processing tool having a rotational or longitudinal axis to at least one spider arm of a rotatable spider assembly of a surface processing apparatus, the spider arm having a leading side and a trailing side as a function of the direction of rotation of the spider assembly. The mounting adapter has a first element for removably attaching the adapter to the spider arm and a second element positioned circumferentially offset behind the first element for positioning the rotational or longitudinal axis of a surface processing tool circumferentially offset behind the trailing side of the spider arm. The first element is an elongate apertured bar and the second element is weld filler material, the bar being connected to said surface processing tool via the weld filler material.

Powered concrete finishing apparatus including a working head for working the concrete. The working head has a rotatable working surface having a ring shape in contact with the concrete during a finishing operation. The concrete finishing apparatus further includes a motor for driving the working head to perform a rotational working movement on the concrete during the finishing operation. The working surface comprises a clearance for allowing concrete to aggregate within said clearance. The clearance is free of additional working surfaces contacting the concrete during the finishing operation, such as blades, pans, floats or arms, thereby providing an improved finishing of the concrete.

A decorative concrete with a very uniform finish surface and a method of fabricating the same is disclosed. A concrete mixture is poured over a subgrade which defines an exposed surface. The exposed surface is finished with any of several techniques, and the surface is then worked with an abrasive material, and additional techniques are used to color and seal the concrete.

A support structure for a float pan for floating a concrete surface provides an interface between the float pan and a rotating machine. The support structure is characterized by a hub configured for concentric attachment to a rotor, and by trusses that extend radially from the hub, each providing a float pan contact surface and means for attachment to the float pan. Perimetric bracing links the trusses about the perimeter of the support structure. A machine similar to a walk-behind or ride-on trowel but without rotor blades, may incorporate the support structure and operate as a dedicated power flotation machine. Under weight of the machine, the contact surfaces of the trusses conform the float pan to a desired shape or radius of curvature for optimizing a flotation process.

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.

A support structure for a float pan for floating a concrete surface provides an interface between the float pan and a rotating machine. The support structure is characterized by a hub configured for concentric attachment to a rotor, and by trusses that extend radially from the hub, each providing a float pan contact surface and means for attachment to the float pan. Perimetric bracing links the trusses about the perimeter of the support structure. A machine similar to a walk-behind or ride-on trowel but without rotor blades, may incorporate the support structure and operate as a dedicated power flotation machine. Under weight of the machine, the contact surfaces of the trusses conform the float pan to a desired shape or radius of curvature for optimizing a flotation process.

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.