METHODS AND APPARATUSES FOR SURFACE FINISHING CURED CONCRETE
A method and apparatus for finishing cured concrete floors using a riding trowel to which large diameter pans are attached having a balanced distribution of abraders releasably secured to the undersides of the pans. The individual abraders are preferably individually spring biased so as to maintain full contact with the floor when traversing undulations of the floor.
The present application is a continuation application to non-provisional patent application Ser. No. 11/804,911, entitled “METHODS AND APPARATUSES FOR SURFACE FINISHING CURED CONCRETE”, filed on May 21, 2007, and claims priority thereto and the full benefit thereof.
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNone
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BACKGROUND OF THE INVENTION Technical Field of the InventionOwners of facilities having large concrete floors want the floors to be flat, smooth and glossy. Defects or imperfections in a concrete floor surface are unacceptable to most business proprietors and therefore must be removed. Traditional methods used today to improve a concrete surface typically involve epoxy coating of the fully cured concrete surface, and buffing the concrete surface. Buffing techniques involve very little removal of concrete from the surface of fully cured concrete and therefore imperfections may remain. Grinding of the surface has been employed, however, current practices do not adequately removing certain defects, such as a shoe imprints in the concrete surface, do not produce as flat a surface as the owner may want, can not be made as flat as desired due to exposing aggregate and take too much time, which is almost always a negative from the owner's viewpoint. Currently concrete finishers use multiple small disks affixed to each of the blades at the base of a troweling machine; the machine applying power causing the blades to rotate with the abrasive surface of the disks in contact with the concrete surface. The weight of the machine acting directly upon the grinding disks is used for the application of the downward force acting on the disks. However, even this prior practice does not achieve the desired smooth glossy finish. Application of a water based surface hardener chemical, such as Diamond Hard marketed by Euclid Chemical Company, followed by polishing with a polishing machine, such as a Tenant polishing machine, has been employed on poured concrete surfaces after the concrete has been allowed to fully cure for 28 days. This last mentioned procedure does produce a somewhat shiny surface but not the degree of gloss desired by the owners of the facilities and it does not remove surface defects or blemishes such as battery acid spills, oil and the like or surface irregularities such as foot prints which may have been pressed into the surface before the concrete had completely cured, and which, if not removed, will adversely affect the surface appearance even though polished.
BRIEF SUMMARY OF THE INVENTIONThe herein disclosed new apparatus technology plus new methods of using this technology includes smoothing a cured concrete floor using a large number of relatively small resiliently biased abraders mounted on a large rotating pan to remove imperfection in the surface without removing an excessive amount of surface material, thereby avoiding contact with large aggregate. By using the herein disclosed flattening and polishing method and apparatus with and without a surface hardener, a surface finish and shine is produced which resembles an automotive painted surface or polished ceramic tile. Achieving such an improved surface finish is accomplished through use of a very large diameter rotating pan having abrasive surface abraders which serve to flatten and polish a hardened concrete floor. A very large diameter pan can be releasably connected to each set of blades of a riding trowel or connected directly to each of its vertical trowel drive shafts.
Customers having merchandise establishments want the surface of their concrete floors to be level, smooth and polished. The riding trowel is typically used to smooth partially cured large concrete floors. Such machines force course aggregate about on eighth of an inch below the surface of the uncured concrete. The herein disclosed method and apparatus abrades the surface without exposing course aggregate and polishes the surface of cured concrete to produce a satin shiny finish.
The accompanying drawings illustrate apparatus pertinent to the invention:
Referring to
Referring to
The desired surface flatness and high glossy finish are achieved by using large diameter pans to which sets of abrading disks are releasable attached in balanced distribution, such as shown in
After the concrete floor has been poured, troweled and hardened, the finishing process begins in which progressively finer grit floor finishes are developed. The floor is abraded and polished in sequential steps using sets of abraders having progressively finer grit. The sequence of flattening and polishing the concrete is critical to achieving the desired degree of surface smoothness and high gloss. The sequence of steps in a preferred embodiment is to spray water on the floor and start with a set of abraders having a 50 grit diamond surface followed by one or more grinding passes using sets of abraders with progressively finer grits to about 400 grit. Water is preferably applied to the concrete surface prior to each flattening step and the floor is preferably vacuumed after abrading and prior to the next step. A standard liquid removal machine may be used to vacuum up the foreign material which typically includes water which is mixed with concrete dust and abrader particles as a result of the flattening step. The concrete surface is then allowed to dry.
Next a suitable liquid hardener such as the Diamond Hard marketed by Euclid Chemical may be applied, as by spraying, to the surface of the concrete. Excess liquid is removed, as by vacuum. The surface of the concrete is allowed to dry. The next polishing steps employ the large rotating circular pans with sets of abraders or a single large diameter abrader disk. The floor polishing is achieved by using sets of progressively finer grit abraders selected from the grit sizes between 400 and 3,500 grit. The floor surface is vacuumed after each step to remove liquid and powder. The liquid hardener makes the surface of the concrete very hard and durable. If a liquid chemical is not used, the above steps of using sets of abraders with progressively finer grits selected from between 400 and 3,500 must still be performed to achieve the desired degree of surface smoothness and gloss of the concrete surface. The end result is a very smooth and high gloss surface.
In the concrete finishing process, the total amount of concrete that will be removed from the original concrete surface will be less than ⅛ inch. The surface finish method does not grind into the aggregate which after troweling poured concrete is normally at least ⅛ inch below the floor surface. The purpose of the progressive increase in the grit number is to reduce the surface porosity of the concrete. If a chemical is used, it is applied following the grind using the first plurality of sets of 50 to 400 grit surfaced abraders in order for the chemical to be able to soak easily into the surface of the concrete. If the porosity of the concrete is too low, the chemical will not soak in properly.
One of the most significant benefits of this new technology is the ability to achieve a highly polished concrete surface. This is achieved by using relatively large diameter rotating pans with sets of abraders to which sufficient downward force is applied to remove surface defects, oil spots, battery acid, tire marks and the like. The pan may be 24 to 86 inches in diameter. Attaching the sets of abraders to the pan by VELCRO material makes it easy and less time consuming to progressive change the abraders during the sequential steps in finishing the floor. Also, excessively worn abraders can be replaced without replacing the pan. The VELCRO connection saves time in switching between sets of coarse abraders with diamond chips embedded in their surface for relatively coarse finishing and in switching between sets of abraders with embedded fine grit for high polish finishing.
A pan with flattening or polishing sets of abraders can be connected either to the trowel blades of each trowel or to one of the vertical trowel blade drive shafts of a riding trowel machine. The spring biased abrader assemblies 77 are particular advantageous in sequentially polishing the floor with the second plurality of sets of abraders having for instance 400, 800, 1,500 and 3,500 grit, respectively. However abrader pads of the first plurality of sets of abraders, with 4 to 400 grit can also be advantageously used in the spring biased abrader assemblies 77.
The steps to follow in practicing the inventive method on a concrete surface that has been allowed to fully cure for the full 28 days can be summarized as follows:
1. Spray or otherwise apply water to the surface of the fully cured concrete.
2. Using a riding toweling machine grind off a small thickness (less than ⅛″) of the surface of the concrete in the following manner:
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- a. Use a 24 to 86 inch diameter pan with sets of abraders from a first plurality of sets of abraders having a grit surface between 50 and 400 grit. The rpm of the pan should be between 150 and 200 and the downward thrust of the pan on the floor should be between 1.4 and 2.5 pounds per square inch.
- b. After abrading with each set, vacuum up the water and concrete powder that has been generated. Allow the surface to dry and then spray water on the concrete surface.
3. If a liquid hardening chemical is used, it is next applied as by spraying a measured amount onto the concrete surface. The chemical hardening solution should be allowed to penetrate into the pores of the concrete and to cure. If the hardening solution dries too quickly water is sprayed on the concrete surface to insure penetration of the chemical into the floor surface. After the chemically treated concrete has dried, spray water on the surface of the concrete. Then polish the concrete using a second plurality of sets of progressively finer grit surface abraders within the range of 400 to 3,500 grit using the riding trowel machine to which the correct amount of weight has been added to give the required amount of downward force. After each abrading step the concrete surface is vacuumed to remove foreign particles.
The embodiments shown in
The foregoing description and drawings comprise illustrative embodiments of the present invention. Having thus described exemplary embodiments of the present invention, it should be noted by those skilled in the art that the within disclosures are exemplary only, and that various other alternatives, adaptations, and modifications may be made within the scope of the present invention. Merely listing or numbering the steps of a method in a certain order does not constitute any limitation on the order of the steps of that method. Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Accordingly, the present invention is not limited to the specific embodiments illustrated herein, but is limited only by the following claims.
Claims
1. A concrete finishing apparatus comprising:
- an annular pan, wherein said annular pan is removably secured to a plurality of rotating blades.
2. The concrete finishing apparatus of claim 1, wherein each of said plurality of blades comprises a leading edge, and wherein said plurality of blades rotates around a central axis.
3. The concrete finishing apparatus of claim 2, wherein said annular pan further comprises a rotational axis, wherein said rotational axis of said annular pan is coaxial with said central axis.
4. The concrete finishing apparatus of claim 3, wherein said annular pan further comprises angle-shaped brackets, and wherein said angle-shaped brackets are dimensioned to receive said leading edges of said plurality of blades.
5. The concrete finishing apparatus of claim 4, wherein said angle-shaped brackets comprise a horizontal member.
6. The concrete finishing apparatus of claim 5, wherein said annular pan is removably secured to said plurality of blades via said angle-shaped brackets.
7. The concrete finishing apparatus of claim 6, wherein said leading edges of said plurality of blades are received by said angle-shaped brackets and are disposed in contact with said angle-shaped brackets during rotation of said plurality of blades, and wherein said horizontal member prevents vertical separation of said annular pan from said plurality of rotating blades.
8. The concrete finishing apparatus of claim 7, wherein said plurality of blades rotate in a direction that applies force by said leading edges of said plurality of blades against said horizontal member, thereby retaining said plurality of blades within said angle-shaped brackets.
9. The concrete finishing apparatus of claim 8, further comprising an abrading surface, wherein said abrading surface is removably secured to said annular pan.
10. The concrete finishing apparatus of claim 9, wherein said abrading surface is secured to said annular pan by hook-and-loop fasteners.
11. The concrete finishing apparatus of claim 10, wherein said abrading surface comprises a plurality of abraders.
12. The concrete finishing apparatus of claim 11, wherein each of said plurality of abraders is disposed on a thrust transmitting unit.
13. The concrete finishing apparatus of claim 12, wherein said plurality of abraders comprises abraders having a shape selected from the group consisting of disc-shaped abraders, pie-shaped abraders, and combinations thereof.
14. The concrete finishing apparatus of claim 13, wherein said abraders have a balanced distribution about an underside portion of said annular pan.
15. The concrete finishing apparatus of claim 14, wherein said abraders are positioned in concentric circles.
16. A method of finishing concrete, said method comprising the steps of:
- obtaining a concrete trowel having at least one annular pan and at least one set of rotating blades, wherein said at least one annular pan comprises a rotational axis and removably-secured abrading pads, and wherein said at least one set of rotating blades comprises a central axis around which said blades rotate, and wherein said at least one annular pan is removably secured to said at least one set of rotating blades, and wherein said rotational axis and said central axis are coincident; and
- rotating said at least one set of rotating blades and said at least one annular pan while said abrading pads of said at least one annular pan are in contact with a floor section to be rendered smooth.
17. The method of claim 16, further comprising the step of:
- removably securing said at least one annular pan to said at least one set of rotating blades via a set of angle-shaped brackets, each bracket of said set of angle-shaped brackets having a horizontal flange, and wherein each of said angle-shaped brackets is dimensioned to receive a corresponding rotating blade of set of said rotating blades, said rotating blade applying force against its corresponding angle-shaped bracket, and wherein said horizontal flanges prevent vertical separation of said at least one annular pan from said at least one set of rotating blades.
18. A concrete finishing apparatus comprising:
- at least one annular pan having a plurality of angle-shaped brackets disposed on a top surface of said at least one annular pan, wherein each of said plurality of angle-shaped brackets comprises a horizontal flange; and
- at least one set of rotating blades, wherein each blade of said at least one set of rotating blades comprises a leading edge, and wherein said leading edges apply force against said angle-shaped brackets when said at least one set of rotating blades is rotated, and wherein said horizontal flange retains said blade between said angle-shaped bracket and said top surface of said at least one annular pan, and wherein said horizontal flange prevents vertical separation of said at least one annular pan from said at least one set of rotating blades.
19. The apparatus of claim 18, further comprising:
- removably-secured abrading pads, wherein said removably secured abrading pads are disposed on a bottom surface of said at least one annular pan.
20. The apparatus of claim 19, wherein said removably-secured abrading pads are secured to thrust transmitting units.
Type: Application
Filed: Feb 13, 2009
Publication Date: Jun 18, 2009
Inventor: Paul Copoulos (McDonough, GA)
Application Number: 12/371,049
International Classification: B24B 23/02 (20060101);