Abstract: A portable vibratory screed includes a blade that is connected to a handle constructed to be manipulated by an operator. Nodes of minimum vibrational amplitude are formed at specific locations along the length of the blade when the exciter is driven at a rated operating speed. A site level and/or the handle is attached to the blade at or in the vicinity of one or more of these nodes, therefore, is relatively isolated from induced vibrations.

Abstract: A portable vibratory screed includes a blade that is connected to a handle constructed to be manipulated by an operator. Nodes of minimum vibrational amplitude are formed at specific locations along the length of the blade when the exciter is driven at a rated operating speed. A site level and/or the handle is attached to the blade at or in the vicinity of one or more of these nodes, therefore, is relatively isolated from induced vibrations.

Abstract: 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.

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.