Transformable two-person floating screed with automatic grade control

• US 6,089,787 A
• Filed: 05/26/1998
• Issued: 07/18/2000
• Est. Priority Date: 05/26/1998
• Status: Expired due to Fees

• Current Assignee: Allen Engineering Corporation
• Original Assignee: Allen Engineering Corporation
• Inventors: Allen, J. Dewayne, Guinn, Timmy D.
• Primary Examiner(s): Lillis, Eileen Dunn
• Assistant Examiner(s): Hartmann, Gary S.
• Application Number:
  US09/084,282
• Time in Patent Office: 784 Days
• Field of Search: 404/97, 404/114, 404/118
• US Class Current: 404/118
• CPC Class Codes: E01C 19/006 by laser or ultrasound
• CPC Class Codes: E01C 19/402 the tools being hand-guided
• CPC Class Codes: E04F 21/242 with vibrating means, e.g. vibrating screeds

Abstract

A two-person floating screed with laser-operated, automatic grade control apparatus for finishing plastic concrete is transformable for different operations. A rigid, transversely oriented float mounts a strikeoff for initially contacting and leveling rough, freshly poured concrete. In one form of the invention the screed merely floats upon the concrete surface. In an alternative embodiment, lightweight ski assemblies support the screed over the subgrade. The skis secure upwardly projecting screw jacks that removably couple to the screed and control elevation of the transverse float in response to laser signals. Each worker has a separate handle mechanism pivotally associated with the float. Separate, light-weight power sources are carried by each worker in a suitable backpack to power the screw jacks. Laser sensors mounted on vibration dampened stanchions emanating from the float respond to external laser beacons and display grade information so that the workers can make manual adjustments. With the ski assemblies attached, the laser system automatically controls float elevation by activating the screw jacks so that the extend or contract. The float preferably comprises twin sections that are secured together in the two person mode. When uncoupled, the float divides into a pair of separate, compact one-person floating screeds.

Claims

1. A floating screed for treating plastic concrete that can be switched between a single large screed requiring two person operation or twin separate screeds allowing single person operation, said screed comprising:

an elongated concrete finishing float adapted to be floated upon said concrete above a subgrade, said float comprising strike-off means for cutting, striking off and leveling rough, uneven freshly poured concrete, wherein the finishing float comprises twill sections and clamp means for normally holding the twin sections together for two person operation, the clamp means enabling the twin sections to be separated to transform the screed into twin single-operator floating screeds;

vibrator means for vibrating said float and said concrete to smooth and settle the concrete;

a laser-operated, automatic grade control apparatus comprising a remote source of laser light, and sensor means for receiving said light mounted to the screed;

quick connect ski means for supporting the screed above the subgrade, said ski meals comprising a ski riding on the subgrade and screw jack means mechanically extending between said ski and sad screed for controlling the elevation of the finishing float above the concrete by extending or retracting in response to said sensor means, wherein said quick connect ski means comprises connecting rods, mating sleeves to which said connecting rods are removably coupled, and said ski means comprises a pair of extensible stabilizer sleeves, one disposed on each side of said screw jack means; and

,

a pair of spaced apart control handles, one for each worker.

2. The screed as defined in claim 1 further comprising backpacks worn by the workers and a portable power source disposed within said backpacks worn by the workers for powering the screw jack means.