Wacker Corporation

Gregory Kruepke

Michael Jenkins

Todd J Lutz

Richard D Goldberg

Darrin W Dauffenbach

Michael D Braun

Michael Ochalek

A starter module configured to limit an engine speed of an engine for a walk behind trowel at time of startup. The walk behind trowel includes a rotor driven by the engine, a throttle to command an operating state of the walk behind trowel, and a clutch operable to selectively couple an output of the engine to the rotor. The starter module includes a sensor operable to provide a signal representative of an operating state of the trowel upon engine start-up. The starter module further includes a controller configured to receive the signal representative of the operating state of the walk behind trowel, and to prevent the clutch from engaging the engine output to drive the rotor if the detected operating state is outside of a designated range for idling operation of the engine.

Starter module for walk behind trowel

A method is provided of making and using a walk behind rotary trowel that is '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 method 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.

Method of making and using a dynamically balanced walk behind trowel

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.

Guide handle for a manually steered machine

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.

Dynamically balanced walk behind trowel

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.

Trowel gearbox brake

Walk behind rotary trowel guide handle

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.

Growing community of inventors

Waukesha, WI, United States of America

Gregory Kruepke