Road structure – process – or apparatus – Apparatus – Screed or drag
Reexamination Certificate
2002-06-10
2004-02-24
Pezzuto, Robert E. (Department: 3671)
Road structure, process, or apparatus
Apparatus
Screed or drag
C404S075000
Reexamination Certificate
active
06695532
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a concrete finishing, smoothing and/or leveling apparatus and, more particularly, to a concrete smoothing and leveling apparatus which is operable on partially cured concrete to smooth the partially cured concrete surface to a flat, level surface.
BACKGROUND OF THE INVENTION
There is a growing need in the industry for close-tolerance, flat and level concrete floors for various buildings or structures, such as warehouses, manufacturing facilities and the like. Many manufacturing plants include high-precision equipment which must be level and thus benefit from having close-tolerance floors to allow for easier initial installation, set up and/or reorganization of the equipment. Additionally, high-density warehouse facilities often utilize narrow aisles and high-reach forklifts to reach tall storage racks for shelving. Any offset from level of the floor then corresponds to an offset from vertical of the high-reach forklift, which may result in difficulty in maneuvering the forklifts along the aisles and in reaching the upper shelves. Such warehouse facilities thus also benefit from very smooth and accurately level floors for efficient installation and use of equipment and for stocking of the shelves.
Close-tolerance floors are often referred to in the industry as “super-flat floors” or simply “super flats”. Such super-flat floors are typically expensive for concrete contractors to produce, since such projects usually require specialized equipment and experienced personnel with a thorough knowledge of the process. Because of the high cost of the super-flat floors, often only specified areas of a building floor will be made to super-flat specifications, such as within anticipated aisleways of a given floor plan. However, the spacing or location of the aisles then cannot be easily adjusted later, which increases future renovation costs and possibly the future value and usefulness of the facility.
Close-tolerance, super-flat concrete floors are specified, measured and compared in the concrete industry according to concrete floor profile specification variables. One of these variables is for floor flatness “F-F” and another is for floor levelness “F-L”. These two specifications together are generally referred to in the industry as F-numbers. The F-number system offers a repeatable method for measuring floor quality through statistical means known in the art. Concrete floors having F-numbers near or above the range of F-F 80 and F-L 80 are typically regarded as being super-flat concrete floors.
Super-flat concrete floors are much more difficult and expensive to achieve than those conventionally poured. In order to achieve such super-flat floors, construction work site personnel must be highly trained and skilled, and special equipment is often required to place and finish the concrete. Striking-off wet, uncured concrete to a specified grade for a conventional floor can be performed using hand tools. However, a large number of workers are required to finish the floor, and production speed of the floor is thus relatively slow with such conventional processes. Additionally, as an operator continues to work with the manual devices, such as trowels and scrapers, for a long period of time, the operator will tire as the day goes on, which will have an adverse affect on the final F-numbers and quality of the floor. Therefore, because many flat floors are finished by manual labor, the floors are likely to have relatively poor accuracy in the overall surface levelness and flatness.
In many applications, the use of a laser screeding device, such as the Somero Laser Screed, developed by Somero Enterprises of Houghton, Mich., is often required when the goal of a super-flat floor is to be achieved. Other special application tools and equipment, such as highway straight edges, power trowels, pan machines and double trowels, may be used separately, at the same time, or in combination with one another, during the finishing process. Because a significant amount of time and effort of experienced and skilled workers and special equipment and/or machinery is required to achieve a super-flat floor quality, achieving such a floor is often a relatively expensive and time consuming process.
Many concrete processing applications have implemented a spinning tube, or the like, in constructing a concrete floor or surface. However, such spinning tube applications are implemented as an initial strike-off tool or screed for striking-off or screeding freshly placed and uncured concrete to the desired grade. These tube type roller screeds are necessarily supported on some type of preset forms or screed rails to maintain grade height. Because these screeding devices are applicable only to freshly poured, uncured concrete, implementation of such devices does not result in a close-tolerance or super-flat concrete floor surface. The additional manual processes still have to be performed on the surface after the initial screeding operation is completed, and after the concrete is at least partially cured and set up, in order to obtain such a super-flat, high quality, floor surface.
Therefore, there is a need in the art for a concrete smoothing and leveling apparatus which is capable of finishing a concrete surface to a super-flat or close-tolerance finish. The apparatus should require minimal manual labor processes and be inexpensive to operate over the entire floor surface.
SUMMARY OF THE INVENTION
The present invention is intended to provide a concrete floor or surface finishing apparatus which is operable to finish a surface of a partially cured concrete slab to a super-flat, smooth and level floor surface. The apparatus of the present invention requires minimal manual labor processes to achieve the desired floor surface quality. Additionally, the apparatus of the present invention is applicable to large floor surface areas, whereby the entire floor surface can achieve the desired super-flat and level floor qualities.
According to a first aspect of the present invention, a concrete finishing apparatus for smoothing and leveling partially cured concrete at a support surface includes a movable unit and at least one rotatable finishing member mounted at the movable unit. The movable unit is movable and supported over and/or on the partially cured concrete and is movable in at least a first direction. The at least one rotatable finishing member is an elongated cylindrical member, such as a cylindrical tube, roller, cylinder or the like. The rotatable finishing member includes a longitudinal axis and is rotatable about the longitudinal axis. The rotatable finishing member defines a cylindrical contact surface therealong which is adapted to contact a surface of the partially cured concrete as the rotatable finishing member is rotated over the partially cured concrete. The finishing member is rotatable such that the contact surface moves relative to the surface of the partially cured concrete as the movable unit and the rotatable finishing member are moved over the partially cured concrete.
Preferably, the rotatable finishing member is positioned behind the movable unit as the movable unit moves in the first direction. The finishing member is rotatable in an opposite direction from the first direction such that the contact surface is movable relative to the partially cured concrete surface in the first direction as the movable unit moves in the first direction.
In one form, the rotatable finishing member is vertically adjustable. Optionally, the concrete finishing apparatus may include a laser leveling system. The rotatable finishing member is then vertically adjustable in response to the laser leveling system. The rotatable finishing member may also or otherwise be variably weighted to adjust or vary an amount of force or downward pressure being applied to the partially cured concrete by the rotatable finishing member.
The movable unit of the concrete finishing apparatus includes at least one support which spreads the weight of the movable unit over an area of th
Halonen Philip D.
Kieranen Carl B.
Peterson Robert A.
Pietila Mark A.
Poyhonen Paul H.
Delaware Capital Formation Inc.
Mayo Tara L.
Pezzuto Robert E.
Van Dyke Gardner, Linn & Burkhart, LLP
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