Abstract: A truss screed includes a shaft guard that covers the screed's exciter shaft to protect it from concrete and debris and that protects the surroundings from the rotating exciter shaft. The shaft guard includes a plurality of tubing sections that surround the shaft and that are supported on joints disposed between the guard sections. In a first preferred embodiment of the shaft guard, each joint includes a resilient spring ring, a support cup that receives the spring ring and an end of an associated tubular section, and a bearing that engages the support cup and that supports the joint and a portion of the exciter shaft on the screed's frame. In a second preferred embodiment, each joint includes a support cup that supports an end of the associated tubular section, a bearing, and a U-shaped bracket that couples the support cup to the bearing. The bearing and/or the bracket have elongated slots therethrough for accommodating misalignment of joint components.

Abstract: An air-cooled gearbox assembly for a concrete finishing trowel or the like is configured to maximize its cooling efficiency so as to negate the need to oversize the gearbox of the assembly. The assembly includes an air cooler including vertical fins on the gearbox and a blower. A shroud on the blower interacts with the fins on the gearbox to channel air vertically onto and over the upper and lower surfaces of the gearbox. The shroud also seals against the side edges of the gearbox to prevent the air from short-circuiting airflow passages formed between the fins. The airflow patterns resulting from this arrangement maximize convective heat transfer, thus maximizing cooling efficiency. The gearbox's thermal capacity is therefore considerably enhanced. As a result (all other things being equal), a much lighter gearbox can be used in a given application than otherwise would be required. Weight savings of more than 40% can be expected.

Abstract: A reciprocating impact tool such as a rammer or a breaker is provided with a lubricating oil supply system that supplies lubricating oil to a fuel supply line of the tool's two-cycle engine, thereby eliminating the need to premix the fuel and oil. The oil is supplied at a rate that varies with the speed of the reciprocating member of the tool, thereby assuring that the fuel and oil are mixed in the proper proportions. The oil pump delivers oil to the fuel supply line well-upstream of the engine's carburetor or other fuel supply device, thereby taking advantage of movement and vibration of the reciprocating member to assure that the delivered oil is thoroughly mixed with the fuel in the fuel line before the mixture is inducted into the engine's combustion chamber, leading to complete atomization of the oil and resultant benefits, including improved lubrication and complete combustion of the oil.

Abstract: A self-propelled concrete finishing trowel has a power steering control system that steers the machine by tilting the driven shaft(s) of the rotor assembly or assemblies of the machine without requiring the imposition of fatiguing actuating forces by the machine's operator. The steering control system includes at least one electric actuator, such as a ball screw actuator, coupled to each rotor assembly of the machine and controlled by an operator-manipulated controller. The controller preferably includes at least one, and possibly two, joysticks that can be manipulated by the operator to steer the machine in the direction of joystick motion and preferably at a speed that is proportional to the magnitude of joystick movement. In the typical case in which the machine is steered by pivoting a gearbox of at least one rotor assembly about two axes, a separate actuator is provided for each axis of gearbox pivoting.

Abstract: A power buggy is configured to be safe, stable, easy to control, and comfortable. Frequently-used controls such as dump controls, a speed control, and a directional control, arc located at or very near handgrips of the operator's handle so as to permit the operator to control the vehicle without releasing either of the handgrips. For instance, speed and direction arc both controlled by a bidirectional twist grip forming one of the handgrips. The twist grip must rotate through a neutral position before changing directional control from forward to reverse so that an operator cannot reverse the vehicle's direction of travel without first rather gradually reducing vehicle speed. Operator comfort is also enhanced by a fuel tank that shields the operator from the engine. The fuel tank also has a large capacity while simultaneously functioning as a support for side shrouds of the vehicle.

Abstract: A concrete finishing trowel has one or more driven rotor assemblies coupled to an engine or other power source of the machine by a novel torque transfer system including at least one flexible shaft and possibly including a variable speed ratio torque converter assembly. The flexible shaft, preferably comprising a flexible wound wire shaft, bends to accommodate tilting movement of the associated rotor assembly that occurs upon a steering operation, thereby eliminating the need for high-maintenance universal joints or other, less durable equipment. The torque converter assembly, preferably taking the form of a pair of variable speed clutches each having variable diameter sheaves, permits the speed and torque ratios of the drive system to change with increases in engine speed so that the same machine can be effectively used for both low speed/high torque floating operations and for high speed burning operations.

Abstract: A power buggy is configured to be safe, stable, easy to control, and comfortable. Frequently-used controls such as dump controls, a speed control, and a directional control, are located at or very near handgrips of the operator's handle so as to permit the operator to control the vehicle without releasing either of the handgrips. For instance, speed and direction are both controlled by a bidirectional twist grip forming one of the handgrips. The twist grip must rotate through a neutral position before changing directional control from forward to reverse so that an operator cannot reverse the vehicle's direction of travel without first rather gradually reducing vehicle speed. Operator comfort is also enhanced by a fuel tank that shields the operator from the engine. The fuel tank also has a large capacity while simultaneously functioning as a support for side shrouds of the vehicle.

Abstract: A vertically-extending L-shaped exhaust pipe and method of manufacturing same are disclosed. The exhaust pipe includes a drain hole located at the bottom of the horizontal portion of the exhaust pipe for allowing liquids to drain from the pipe in order to avoid harming upstream exhaust system or engine components. An elliptically shaped guide is welded into an arcuate slot immediately upstream of the drain hole and is angled in the downstream direction so as to direct the flow of liquid toward the drain opening and away from upstream exhaust system components. The present invention is simple to manufacture, eliminates the need for a noisy flapper lid, and maintains the structural integrity of the exhaust pipe.

Abstract: A power trowel incorporates a counterbalanced blade pitch adjust assembly that is relatively easy to manufacture and to install (and hence that can be retrofitted onto an existing power trowel machine) and that is easy to operate. The blade pitch adjust assembly includes 1) a blade pitch adjustment mechanism, 2) a pivotable control lever assembly that is coupled to the adjustment mechanism by a cable or other tension element, and 3) a counterbalancing mechanism such as a torsion spring. The counterbalancing mechanism imposes a force on the control lever assembly that is significantly lower than the resistive force imposed on the control lever assembly by the tension element to avoid potentially dangerous control lever snap-back and to provide the operator with a sense of feel as he or she adjusts blade pitch.

Abstract: A spring applied, hydraulically released (SAHR) parking and emergency brake system 1) can be manually overridden to permit towing or assisted vehicle transport when charge pump pressure is unavailable for the brakes, and 2) is reset either a) automatically when charge pump pressure becomes available or b) manually. Override is made possible by a manual override assembly that includes a manually-actuated hand pump and an override valve. The override valve is manually actuated to isolate the brake release actuators and the outlet of the hand pump from the system's reservoir and is reset to its open position in response to the presence of hydraulic pressure at a designated location of the braking system. Automatic reset of the override valve preferably is effected by the supply of pressurized fluid to a previously-unpressurized port of the override valve. The hand pump, override valve, and any other brake control valve(s) of the braking system preferably are incorporated into a single control module.

Abstract: A vibratory plate machine has an improved baseplate, console, clutch, and/or cage assembly. The baseplate has a semi-spherical bottom surface and barrel-shaped side surfaces to improve stability and maneuverability. The baseplate also has ribs on its upper surface configured to maximize stiffening ability and to channel debris off from the baseplate. The console is formed from a single cast metal element to reduce weight and to reduce assembly complexity and to permit shockmounts to be connected to the extreme corner portions of the console. The clutch is configured to distribute as much weight as practical to its outer diameter so that it functions as a flywheel to reduce jerking effects on the driven belt to reduce belt wear and increase belt life. The cage assembly is configured to maximize protection of sensitive components of the machine from external shocks and to facilitate machine lifting.

Abstract: A water supply system is adapted to spray lubricant, typically water, onto an asphalt surface in front of an asphalt vibratory plate machine at a generally constant rate regardless of the level of lubricant in the system's storage tank and regardless of machine inclination. The water is routed to a nozzle assembly of the water supply system through a pump that is preferably driven by the exciter of the asphalt vibratory plate machine. The pump is configured to provide adequate pressure with minimal increase in the machine's overall weight, complexity, or manufacturing expense. The nozzle assembly includes a spray bar which is configured to spray water uniformly across the entire compaction path but which is shorter than the baseplate of the machine so as to avoid snagging on neighboring obstructions.