Abstract: A guide handle of a handle assembly for an industrial machine such as a walk behind trowel has the open-ended handlebar characteristics of a so-called “bicycle” style guide handle and the belly bar and gripping versatility characteristics of a “whale tail” style guide handle. The belly bar spans the gap between the two handgrip portions, and both portions are mounted on a center post of the handle assembly at the bottom leg of a generally U-shaped mounting portion. The mounting portion can be welded or otherwise affixed to a post of the handle assembly at any desired angle, thereby permitting the orientation of the guide handle to be optimized for a given guide handle height.

Abstract: A trowel blade for use with power trowels includes a plastic trowel blade having a reinforcing metal plate affixed to and overlying at least a portion of one face thereof. The blade is adapted for use in combination with a power trowel having a rotor including a plurality of rotor arms for mounting trowel blades thereon.

Abstract: A concrete finishing machine having a rotatable trowel blade assembly and a mechanism for controllably adjusting the pitch of the trowel blades relative to a wet concrete surface on which the blades rest. The machine's engine's drive shaft rotation itself is utilized to create changes in pitch.

Abstract: Disclosed is a vibration dampening handle for power tools. It includes a branch handle attached to a main handle, but at least one resilient connection. The upper connection is through a resilient connection, and the lower connection is typically a solid connection.

Abstract: A rotary cement or concrete finishing trowel has an operating head at one end of the apparatus that includes at least one cement finishing blade rotatably mounted for movement in a horizontal plane for smoothing a concrete floor surface. A drive motor, e.g., a 2-cycle gas engine, is provided at the other end of the apparatus. An elongated frame element is connected between the motor framework and the operating head and is preferably rigidly connected between them. A drive shaft extends diagonally between the motor and the operating head for imparting rotation to the finishing blade.

Abstract: A light weight motorized concrete finishing machine with a set of blades that rotate on a single plane, held by a hub assembly that resists deflection, specially equipped with quick release system for trowel blades. Blade pitch is controlled by an actuator that can be adjusted manually or remote powered. The unit is equipped with a remote means of hands free operation of blade pitch and throttle control. Right to left directional motion of machine is controlled by an articulated steering mechanism.

Abstract: A walk behind rotary trowel is configured to be “dynamically balanced” so as to minimize the forces/torque that the operator must endure to control and guide the trowel. Characteristics that are accounted for by this design include, but are not limited to, friction, engine torque, machine center of gravity, and guide handle position. As a result, dynamic balancing and consequent force/torque reduction were found to result when the machine's center of gravity was shifted substantially relative to a typical machine's center of gravity. Dynamic balancing can be achieved most practically by reversing the orientation of the engine relative to the guide handle assembly when compared to traditional walk behind rotary trowels and shifting the engine as far as practical to the right. This shifting has been found to reduce the operational forces and torque the operator must endure by at least 50% when compared to traditional machines.

Abstract: A brake of a concrete finishing trowel responds automatically to the cessation of drive torque delivery to the rotor to actively brake the trowel's drive train, hence inhibiting or preventing frame rotation. The brake preferably takes advantages of inherent characteristics of an inclined gear, such as a worm of a gearbox, to permit an internal component of the gearbox to shift automatically upon the cessation of drive torque therethrough from a brake released position to a brake engaged position. In the case of a worm gear-based gearbox, the worm is configured such that reaction forces that are normally generated by the delivery of drive torque therethrough shift the worm to release the brake during normal trowel operation. These forces are eliminated in the absence of drive torque transfer, permitting the worm to shift to a brake engaged position.

Abstract: A power trowel is provided for finishing concrete. The trowel can be used to finish concrete at different stages of hardening. The handle of the trowel is rotated both to adjust the speed of rotation of the trowel blades and the cant of the trowel blades.

Abstract: Methods and apparatus for power finishing freshly placed concrete in which the acoustic impedance of the treating equipment is made substantially equal to the acoustic impedance of the concrete slab being treated. Preferably, a powered, twin rotor riding trowel is provided with a pair of circular finishing pans that are attached to the conventional rotor blades used later in the finishing process. The pans are characterized by an acoustic impedance approximating the acoustic impedance of green concrete, thereby optimizing the energy transferred to the concrete. Preferred pans comprise ultra-high molecular weight polyethylene (UHMWPE) plastic. During troweling, the pans are frictionally revolved over the green concrete for finishing the surface without prematurely sealing the uppermost slab surface. Through the disclosed troweling method, a highly stable concrete surface results, and delamination is minimized. Alternative troweling uses pans coated with layered impedance matching material.

Abstract: A control module for a walk behind trowel configured to detect and to prevent an uncontrolled or undesirable motion of the trowel. The trowel includes an engine configured to drive rotation of a rotor. The control module includes a gyroscope and a controller. The gyroscope is configured to provide an electrical signal representative of an angular rate of motion of a reference structure on the walk behind trowel. The controller is configured to receive the electrical signal from the gyroscope and to determine when a change in the angular rate of motion of the trowel exceeds a threshold value, and in response, to prevent the engine from driving the rotor to rotate.

Abstract: A concrete finishing machine having a rotatable trowel blade assembly and a mechanism for controllably adjusting the pitch of the trowel blades relative to a wet concrete surface on which the blades rest. The machine's engine's drive shaft rotation itself is utilized to create changes in pitch.

Abstract: A power trowel is provided for finishing concrete. The trowel can be used to finish concrete at different stages of hardening. The handle of the trowel is rotated both to adjust the speed of rotation of the trowel blades and the cant of the trowel blades.

Abstract: A rotary power trowel machine for finishing concrete surfaces and more particularly to a quick adjustment mechanism for the pitch of the blades. The quick adjustment mechanism includes a control lever mounted on the operating handle of the trowel in a position to be easily grasped and operated by a trowel operator. The control lever changes the blade pitch through a mechanical advantage linkage which reduces the force applied to the control lever to adjust the blade pitch. The control lever includes a locking mechanism to lock the control handle and linkage in selected positions to lock the blades at a desired pitch angle. The locking mechanism includes a semicircular guide mounted on the trowel operating handle and extending through openings in the control lever. A locking device on the control lever lockingly engages the guide and is selectively locked and released from an upper end of the control lever.

Abstract: A device for levelling a recently poured floor, in particular a concrete floor, which device substantially comprises a frame with a drive motor, the drive shaft of which stands upright, and a rotor connected to the shaft and having two or more blades which are directed radially relative to the shaft and each of which can be placed at an angle relative to the shaft, wherein an annular support member is arranged concentrically round the drive shaft and is pivotally connected to each blade at a distance from the shaft such that a rotation of the ring brings about an equal and simultaneous tilting of each blade, whereby a precise operation of the machine and a better finishing of the floor is achieved.

Abstract: A concrete tool assembly (10) used on a concrete surface (16) includes a surfacing apparatus (12) including a frame (18) and one or more trowel assemblies (34A, 34B). Each trowel assembly (34A, 34B) includes one or more trowels (54). The concrete tool assembly (10) also includes a remote control unit (14) that controls movement of the trowel assemblies (34A, 34B) relative to the concrete surface (16). The remote control unit (14) can be mechanically and/or electrically isolated from the surfacing apparatus (12). The surfacing apparatus (12) can be radio-controlled by the remote control unit (14). The surfacing apparatus (12) can also include a plurality of shafts (74A, 74B) that are each coupled to a corresponding trowel assembly (34B, 34B). A portion of each shaft (74A, 74B) can pivot relative to the frame (18). Further, the surfacing apparatus (12) can include a controller (24) that receives commands from the remote control unit (14).

Abstract: The rotor blade for a mechanical trowel, such as a concrete polisher, comprises a blade arm (20), a spacer bar (22), and a blade plate (24). The spacer bar (22) is not integral with the blade plate (24). Through-bolts (30) with nuts (44) run through unthreaded through-holes (32, 34, 36) formed in the plate (24), the spacer bar (22), and the blade arm (20). After the removal of the bolts (30), the plate (24) is separated from the spacer bar (22).

Abstract: A light weight motorized concrete finishing machine with a set of blades that rotate on a single plane, held by a hub assembly that resists deflection, specially equipped with quick release system for trowel blades. Blade pitch is controlled by an actuator that can be adjusted manually or remote powered. The unit is equipped with a remote means of hands free operation of blade pitch and throttle control. Right to left directional motion of machine is controlled by an articulated steering mechanism.

Abstract: A trowel machine has replaceable blades. In a preferred embodiment, the blade can be replaced separately from the backing bar, and the same fasteners that secure the blade to the backing bar also secure to the trowel arm of the machine. In a preferred embodiment, the blade is deformed in the area of the mounting holes, providing an interlocking, clamping surface recessed from the working surface of the blade, so that there is retention of the blade on the trowel machine, even as the blade wears.

Abstract: A roller wall guard system for use on a surface-finishing machine having a circular guard ring of a given circumference made up of a pair of wall guards. Each wall guard has an arc shaped arm having a first end attached to a roller and extending along a length to a second end also having a roller. Each arm is pivotally connected to the surface-finishing machine at an intermediate location between the first and second ends, so that the arm pivots within a controlled arc. The length of the arms and the diameters of the rollers are configured to define a line between a point of rolling engagement of the first roller against a second surface and a point of rolling engagement of the second roller against the second surface. The line lies outside of the circumference of the guard ring.

Abstract: A rotary power trowel machine for finishing concrete surfaces and more particularly to a quick adjustment mechanism for the pitch of the blades. The quick adjustment mechanism includes a control lever mounted on the operating handle of the trowel in a position to be easily grasped and operated by a trowel operator. The control lever changes the blade pitch through a mechanical advantage linkage which reduces the force applied to the control lever to adjust the blade pitch. The control lever includes a locking mechanism to lock the control handle and linkage in selected positions to lock the blades at a desired pitch angle. The locking mechanism includes a semicircular guide mounted on the trowel operating handle and extending through openings in the control lever. A locking device on the control lever lockingly engages the guide and is selectively locked and released from an upper end of the control lever.

Abstract: A gearbox for a self-propelled power trowel for finishing a concrete surface having a rigid frame adapted to be disposed over a concrete surface, an engine assembly, at least one rotor assembly. The gearbox uses an input shaft having a first bevel gear, an intermediate shaft having a second bevel gear and a first helical gear, and an output shaft having a second helical gear to connect the engine assembly to the rotor assembly to accomplish a double reduction.

Abstract: A high performance, riding trowel for finishing concrete comprises damage-preventing edge guard systems that accommodate destructive forces occasioned by collisions or impacts. Downwardly projecting, motor-driven rotor assemblies gimbaled to the frame contact the concrete with multiple blades for finishing. The rotors are tilted with linkages ideally controlled by a powered system that enhances operator control. A two-piece guard system is concentrically disposed over and rotatably associated with each rotor. The guard system comprises a captivating guard frame borne by the rotor and tilted during steering, which captivates and supports a rotatable ring guard portion that may non-destructively impact obstacles. The guard system frame suspends a plurality of rollers comprising upper and lower flanges. The rotatable guard ring is captivated upon the rollers, being vertically constrained between the flanges.

Abstract: A finishing device for floors made of hardenable material including a frame, at least one rotating tool connected to the frame and a driving mechanism provided on the frame and configured to drive the at least one rotating tool. The rotating tool includes at least two arms that each have a blade connected thereto via a connection arrangement. The connection arrangement includes a first part mounted onto the blade and a second part connected to the arm. The first arm connects to the second part and slidably engages therewith such that the blade can be adjusted and fixedly clamped along a longitudinal dimension of the arm.

Abstract: A pavement coring machine having rotating cutting heads of various diameter, the optimum speed of rotation of the heads varying with the diameter of the cutting head and the nature of the pavement being cored has a direct reading tachometer positioned to be observed by an operator of the machine, the tachometer being operatively connected to display the speed of rotation of the cutting head. A method of operating the machine includes determining the optimum speed of rotation of a cutting head, and regulating the speed of the cutting head as displayed by the direct reading tachometer.

Abstract: A rotary power trowel machine for finishing concrete surfaces and more particularly to a quick adjustment mechanism for the pitch of the blades. The quick adjustment mechanism includes a control lever mounted on the operating handle of the trowel in a position to be easily grasped and operated by a trowel operator. The control lever changes the blade pitch through a mechanical advantage linkage which reduces the force applied to the control lever to adjust the blade pitch. The control lever includes a locking mechanism to lock the control handle and linkage in selected positions to lock the blades at a desired pitch angle. The locking mechanism includes a semicircular guide mounted on the trowel operating handle and extending through openings in the control lever. A locking device on the control lever lockingly engages the guide and is selectively locked and released from an upper end of the control lever.

Abstract: A trowel machine has replaceable blades with an improved mounting arrangement. In a preferred embodiment, the blade can be replaced separately from the backing bar, and the same fasteners that secure the blade to the backing bar also secure to the trowel arm of the machine. In a preferred embodiment, the blade is deformed in the area of the mounting holes, providing a good interlocking, clamping surface recessed from the working surface of the blade, so that there is good retention of the blade on the trowel machine, even as the blade wears.

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 trowel machine has replaceable blades. In a preferred embodiment, the blade can be replaced separately from its backing bar, and the same fasteners that secure the blade to the backing bar also secure the blade to the trowel arm of the machine. In a preferred embodiment, the blade is deformed in the area of the mounting holes, providing a clamping surface recessed from the working surface of the blade to provide retention of the blade on the trowel machine.

Abstract: An improved gearbox for a self-propelled power trowel for finishing a concrete surface having a rigid frame adapted to be disposed over a concrete surface, an engine assembly, at least one rotor assembly. The improved gearbox uses an input shaft having a first bevel gear, an intermediate shaft having a second bevel gear and a first helical gear, and an output shaft having a second helical gear to connect the engine assembly to the rotor assembly to accomplish a double reduction.

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 road finisher has a chassis and a floating laying beam, which is located behind the chassis. The beam includes a centrally divided basic beam, and extendable beams which can extend laterally from the basic beam and can be height-adjusted, with respect to the basic beam. The basic beam and the extendable beams are arranged offset one behind the other in the direction of travel. The height adjusting devices are adjusted automatically in such a way that they keep the respective rear edges of the basic beam and of the extendable beams in the same plane. A control signal for the height adjusting devices is derived from measured values for the setting angle of the basic beam. The control signal is picked up by a sensors on the front of the tie bars for measuring the distance from a reference plane independent of the road finisher, and utilized to determine the height of the rear edge of the basic beam and of the extendable extendable beams.

Abstract: A dolly for transporting a heavy object has a frame, a lifting element, and a pair of wheels. The lifting element engages a lifting point of the heavy object to enable the dolly to support the heavy object for wheeled movement. The frame is shaped to fit around the heavy object when the lifting element is removably attached to the lifting point of the heavy object. The lifting element is preferably rotatably connected to the frame to facilitate lifting the heavy object onto the dolly. Each of the pair of wheels is operably attached to the frame and aligned along an axis to support the heavy object between the pair of wheels such that the center of gravity of the heavy object is located approximately on the axis when the lifting element is attached to the lifting point of the heavy object.

Abstract: A trowel blade assembly for use with a rotary surfacing machine with the assembly consisting of a relatively thick, inflexible trowel blade and a relatively thin, flexible finish blade, wherein the latter is secured with respect to the former such that when in operation on a substantially horizontal working surface, with the blade assembly selectively rotated about a horizontal axis, the finish blade is continuously in contact with the working surface regardless of the consequent variable degrees of tilting of the trowel blade with respect to the working surface.

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 trowel handle has controls that permit electronically operating the functions of an engine on the power trowel from the handle. The engine includes a servo controlled carburetor which will permit injecting, upon initial closing, a circuit for starting a quantity of fuel for starting a two cycle engine, which normally has to be done manually, as well as permitting control of a throttle using a trigger switch on the handle. The power trowel further has an elongated pole braced with a slider to prevent twisting under torque and to permit better control of the power trowel from a remote handle. The handle grip is usable in either the elongated pole position, or directly on a shroud for the power trowel.

Abstract: High performance, multiple rotor riding trowels for finishing concrete comprise hydraulic circuitry enabling complete joystick control to the operator. The rigid trowel frame mounts separate spaced-apart, downwardly-projecting, bladed rotor assemblies that frictionally engage the concrete surface. The rotor assembly blades finish the surface while supporting the trowel. The rotor assemblies are tilted with double acting, hydraulic cylinders to effectuate steering and control. Double acting hydraulic cylinders also control blade pitch. Separate gimbaled, hydraulic motors revolve each rotor assembly. A joystick system enables operator hand control with minimal physical exertion. The joystick system activates electrical circuitry that fires solenoid control valves to energize various hydraulic cylinders that tilt the rotors and alter blade pitch. The hydraulic steering control circuit driven by a motor driven pump pressures a flow divider circuit to control the solenoid tilt control valves.

Abstract: A high performance, twin rotor riding trowel for finishing concrete and a joystick operated electro-hydraulic control circuit enabling complete joystick control to the operator. The rigid trowel frame mounts two spaced-apart, downwardly projecting, and bladed rotors that frictionally contact the concrete surface. The rotors are tilted with double acting, hydraulic cylinders to effectuate steering and control. Double acting hydraulic cylinders also control blade pitch. A joystick system enables the operator to hand control the trowel with minimal physical exertion. The proportional joystick system directly controls electrical circuitry that outputs proportional control signals to electrically controlled, proportional, pressure-reducing valves in line with the tilting cylinders. The hydraulic circuitry comprises a motor driven pump delivering pressure to a flow divider circuit. A bypass-valve in line before the flow divider enables an operator to customize the trowel steering characteristics.

Abstract: A high performance, twin rotor riding trowel for finishing concrete and hydraulic circuitry therefor, enabling complete joystick control to the operator. The rigid trowel frame mounts two spaced-apart, downwardly-projecting, bladed rotor assemblies that frictionally engage the concrete surface. The rotor assembly blades finish the surface while supporting the trowel. The rotor assemblies are tilted with double acting, hydraulic cylinders to effectuate steering and control. Double acting hydraulic cylinders also control blade pitch. A joystick system enables the operator to hand control the trowel with minimal physical exertion. The joystick system activates electrical circuitry that fires solenoid control valves that in turn energize the various hydraulic cylinders that tilt the rotors and alter blade pitch. The hydraulic control circuitry comprises a motor driven pump delivering pressure to a flow divider circuit.

Abstract: A high performance, hydraulically-propelled, multiple rotor riding trowel for finishing concrete is controlled with hydraulic circuitry enabling steering wheel and foot pedal control. The rigid trowel frame preferably mounts three separate spaced-apart, downwardly-projecting, bladed rotor assemblies that frictionally engage the concrete surface. The rear rotor assemblies are tilted with double acting, hydraulic cylinders to effectuate steering and control in response to foot pedals. Double acting hydraulic cylinders also control blade pitch. Separate gimbaled, hydraulic motors revolve each rotor assembly. A steering wheel controlling a front, hydraulic steering control valve controls the front tilting cylinder to facilitates steering with minimal physical exertion.

Abstract: A motorized finishing machine has a rotatable guard system enabling it to finish concrete surfaces next to walls, posts, conduits, or other obstacles. Deployed as a concrete trowel, the machine comprises an internal combustion motor that powers a gearbox to revolve a downwardly projecting rotor. Numerous radially spaced-apart finishing blades controlled by the rotor frictionally contact the concrete surface being treated. A protective guard, which circumscribes the rotor, is rotatably suspended by a plurality of rollers. The guard, which is shaped somewhat like a truncated cone, comprises an inner ring coaxially secured above a larger diameter, outer ring. Radially spaced apart spokes extend between the upper and lower rings and brace the guard. The bearing-equipped rollers mounted by radially, spaced-apart arms have upper and lower flanges. The inner guard ring is captivated between the rollers, and it is vertically constrained between the roller flanges.

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 powered riding trowel comprises a pair of releasable, protective, quick access hoods that may be unlatched to quickly expose the power means for service without structural disassembly. In a preferred embodiment, the twin hoods are hinged to the frame. The trowel seat is mounted on an upper planar surface of a releasable shroud disposed between the hoods. The shroud front and rear are preferably removably latched to the frame. Major portions of the shroud and the hoods are formed from rigid, supportive material having airflow pathways for cooling and ventilating the normally protected trowel interior. In an alternative embodiment both hoods are releasably coupled to the frame by spring biased latches.

Abstract: A powered concrete finishing trowel comprises a variable ratio drive train to power one or more revolving rotors. One or more internal combustion motors power two or more downwardly projecting rotors comprising blades that frictionally contact the concrete surface. The rotors are shaft driven by reduction gear boxes. By tilting the rotors steering forces are developed. A variable gear drive unit comprises a variable ratio pulley driven by the motor. A second pulley drives the gear box input shaft, with a drive belt entrained between the pulleys. A linear actuator projecting outwardly from a stationary mounting plate terminates at a bracket assembly whose opposite end is pivoted to a rigid stabilizer that structurally compliments the linear actuator, establishing a fulcrum action applied to the bracket center. The linear actuator deflects the bracket assembly to axially displace portions of the variable ratio pulley to change the effective pulley diameter.

Abstract: A powered riding trowel comprises a protective, quick access support shroud that may be unlatched to quickly expose the power means for service without structural disassembly. The trowel seat is mounted on top of the upper planar surface of the shroud. The shroud front and rear are preferably formed from rigid, supportive material having airflow pathways for cooling and ventilating the shroud interior. Opposite shroud ends integral with the top surface angularly depend outwardly and downwardly. In the best mode one shroud end is hinged to the trowel frame, and the opposite end is releasably coupled to the frame by spring biased latches. The preferred hinge structure comprises an outer hinge portion formed by a pivotal connection of the bottom of one shroud end. A cooperating inner hinge defined by at least one pair of inner braces is coupled to a pneumatic dampener that pivotally terminates within the shroud interior.

Abstract: A method and system are provided for finishing a concrete floor that exce approximately 50 feet in width. A riding trowel of the type that forms a windrow of loosened concrete material in its wake is positioned on the concrete floor. The riding trowel has a straight edge coupled thereto by a support assembly that positions the straight edge to cross the windrow at a substantially perpendicular angle thereto within line-of-sight of an operator. A power assembly is coupled between the straight edge and the riding trowel for independently controlling vertical and pivoting movement of the straight edge. The riding trowel is driven on the concrete floor and the straight edge is moved along the concrete floor simultaneously with the riding trowel.

Abstract: A torque applying device for use with a steering mechanism for a riding power trowel, wherein the torque applying device is pivotally attached to a steering lever at the first end, and to the frame of the power trowel at a second end and in longitudinal alignment with the steering lever when the steering lever is in its at-rest position, and capable of arcuate rotation about its second end from a position where its longitudinal axis is in alignment with the steering lever to a position for imparting a torque force to the lever to assist rotation of the lever when the lever is rotated from its at-rest position for purposes of tilting a power trowel gear box.

Abstract: A high performance, multiple rotor riding trowel for finishing concrete and hydraulic controls therefor, enabling complete hand control to the operator of steering, propulsion, and blade pitch. A rigid trowel frame mounts two or more downwardly-projecting, bladed rotor assemblies that frictionally engage the concrete surface. The rotor assemblies are tilted with double acting hydraulic cylinders to effectuate steering and control. Double acting hydraulic cylinders also control blade pitch. A joystick system enables the operator to hand control the trowel with minimal physical exertion. The joystick system activates solenoid control valves that in turn energize the various hydraulic cylinders that tilt the rotors and alter blade pitch. The rotor gearboxes are mounted to tiltable, pivot steering boxes secured to the frame within suitable mounting regions bounded by rigid frame elements. The rotor assembly blades contact plastic concrete to finish the surface while supporting the trowel.

Abstract: A self-propelled power trowel, for finishing a concrete surface, is provided, having a rigid frame adapted to be disposed over a concrete surface, an engine assembly, and at least a pair of rotor assemblies having rotatable trowel blades. The rotor assemblies are tiltable relative to the frame. Dual-action hydraulic cylinders are provided interconnected between the frame and the rotor assemblies for selectively tilting the rotors to provide steering control to the power trowel. The hydraulic fluid is delivered to the cylinders at variably selectable but constant pressures through the proportional pressure output control valves.

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.