A portable vibratory wet concrete screed includes a blade, an exciter that is selectively driven to induce vibrations in the blade, at least one operator-manipulated handle connected to the blade and extending upwardly and rearwardly, a laser receiver mounted on the screed at a height above an upper end of the handle, and an indicator that is operatively connected to the receiver. The indicator provides a visual indication of the screed height relative to a desired grade. It is located remote from the receiver at a location which, when viewed from the perspective of a person in the vicinity of a screed operator, is at least substantially in a focal area containing the rear edge of the blade. The handle is mounted on the blade so as to be foldable from an upright, operative position in which it extends vertically and horizontally well beyond horizontal and vertical footprints occupied by a combination of the blade and the exciter to a stowed position in which it is positioned at least substantially entirely within the horizontal and vertical footprints.

Portable vibratory laser screed with remote grade indicator and folding handles

A self-propelled concrete finishing trowel has a steering system that counteracts a portion of the load associated with operator manipulation of a steering handle. A steering linkage connects the steering handle to a rotor assembly. A steering assist mechanism, preferably including a torsion bar or a spring, imposes a preload on the steering linkage to reduce handle actuation forces. The steering assist mechanism reduces handle retention forces, required to maintain the handle in a particular position after moving the handle to that position, to less than about 20 lbs throughout the stroke of the operating handle.

Concrete Trowel Steering System

A material leveling system includes a leveling-implement assembly adapted for leveling material to a final grade level, a frame supporting the leveling-implement assembly, and an implement positioning assembly controlling the position of the leveling-implement assembly relative to the frame. The leveling-implement assembly includes an implement that contacts a construction material during the leveling process.

Automatically adjustable rolling screed

The apparatus and method comprise a concrete float with a vibratory additive broadcaster assembly attached therewith. The broadcaster assembly is suspended above the plane of the finishing tool with a vibratory source attached. The broadcaster assembly is filled with an additive and the apparatus is placed on a wet, concrete surface which is to be treated and finished, by a user. Actuation of a power switch by the user activates the vibratory source resulting in the substantial broadcast of additive on to the concrete surface at the desired location(s) on the slab as determined by the user. The additive is then integrated into the concrete by passage of the float over the treated concrete surface.

Apparatus and method for applying additives to a concrete mix

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 portable vibratory screed (10) includes a blade (12) that is connected to a handle (28) constructed to be manipulated by an operator. Nodes (112, 113, 115, 116) 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 (164) and/or the handle (28) is attached to the blade (12) at or in the vicinity of one or more of these nodes, therefore, is relatively isolated from induced vibrations.

Portable vibratory screed with bubble vial inclination indication system

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

PROBLEM TO BE SOLVED: To provide a hand guide type trowel which can be operated and controlled easier than a conventional hand guide type trowel, and to reduce a trouble of an operator in operating and controlling the hand guide type trowel. SOLUTION: The hand guide type trowel to be provided is dynamically balanced, and comprises a frame, a motor which is mounted on the frame and generates rotating power, a guide handle which extends backward from the frame and is operated by an operator, and a rotor including a plurality of blades rotatable around a rotating shaft. Different from a case where the hand guide type trowel is not balanced dynamically, the dynamically balanced hand guide type lever sufficiently reduces a force transmitted to the handle by the rotation of the blades that are in contact with a surface to be finished. COPYRIGHT: (C)2005,JPO&NCIPI

Darrin W. Dauffenbach

Papers

Portable vibratory screed with bubble vial inclination indication system

Method of making and using a dynamically balanced walk behind trowel

Dynamically balanced walk behind trowel

Dynamically balanced hand guide type trowel