Electric Polisher for Concrete Surfaces

Abstract

A battery-powered electric polisher for treating concrete has the operational form of a self-propelled riding trowel. A rigid frame mounts a pair of rotors that descend into contact with the concrete surface. Hydraulic tilting circuits for polisher steering control are activated with joysticks. An electrically driven hydraulic pump powers the tilting circuits. Each rotor drives a lower, circular drive ring comprising a plurality of spokes. Drive ring spokes are nested within rigid channels defined in a lower a support plate so that the latter is removable. A plurality of radially spaced-apart abrasion devices descend from the support plate into contact with the concrete surface.

Description

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention relates generally to the polishing of concrete surfaces such as floors. More particularly, the invention relates to electrically powered concrete polishing machines. Machines within the focus of this invention have traditionally been classified in USPC Class 404, Subclass 112.

II. Description of the Prior Art

Hydraulic riding trowels for finishing concrete are well recognized by those skilled in the art. High power, hydraulically controlled riding trowels are capable of finishing large areas of plastic concrete quickly and efficiently, insuring high quality surfacing results including appropriate smoothness and flatness characteristics. Modern hydraulic power riding trowels comprise two or more bladed rotors that project downwardly and frictionally contact the concrete surface. In advanced machines the rotors are driven by hydraulic drive motors pressured by hydraulic pumps that are in turn powered by a separate, internal combustion engine. The riding trowel operator sits on top of the frame and controls trowel movement with a joystick steering system that tilts the rotors for control. The weight of the trowel and the operator is transmitted frictionally to the concrete by the revolving blades or pans. Frictional forces caused by rotor tilting enable trowel steering as is well known in the art. The following U. S. patents disclose trowels of interest: U.S. Pat. Nos. 4,046,484, 3,936,212, 4,320,986, 4,676,691, 4,977,928, 5, 108,220, 5,613,80, 5,816,740, 5,890,833, 6,089,786, 6,053,660, 6,048,130, 5,816,739, 6,106,193, 6,857,815, 7,108,449, 7,114,876, 7,690,864, 8,388,264, and 8,708,598.

In the last decade concrete riding trowels have been adapted specifically for concrete polishing. Many surface treatments for concrete floors have evolved and improved over the years. Many forms of grinding and polishing exist. For example, motor-powered polishing or treating machines of the type comprising rotors that abrasively contact the floor or surface under treatment exist. Successful floor treatments with known treatment machines typically start with an abrasive grit and cycle towards finer grits. For example, cycling from 30-grit to 40-grit metal bonded diamond to 80-grit metal bonded diamond abrasive and then to 150-grit bonded diamond abrasive or something finer is typical. At this point in the process, a chemical hardener may be applied to the floor's surface to densify the concrete, and polishing begins thereafter. To start polishing, a 100-grit resin diamond bond, may be employed, followed by a 400-grit bond, then an 800-grit bond, concluding with the use of very fine grit ratings between 1500-level and 3500-level. After smoothing the concrete surface, a stain may be applied to the surface of the concrete.

German Pat. No. G9,418,169.1 entitled “Concrete smoothing machine” issued Jan. 26, 1995, to Betontechnik Shumacher GmbH discloses a riding trowel. As the concept of polishing has been added to the standard practices of panning and then blading concrete surfaces, numerous prior art systems have evolved.

For example, U.S. Pat. No. 7,147,548 to Mehrabi issued Dec. 12, 2006, discloses a grinding and cutting head used with a rotating disk driven by a grinding and cutting machine.

U.S. Pat. No. 7,204,745 to Thysell issued Apr. 17, 2007, discloses a circular cleaning disk intended for rotation by a cleaning machine. A number of recesses distributed over the active cleaning surface includes elements containing industrial diamonds used for grinding stone and concrete floors.

U.S. Pat. No. 7,226,347 to Padgett issued Jun. 5, 2007, discloses a walk behind polisher and grinder. A drive motor mounted on a frame provides rotation.

U.S. Pat. No. 7,357,700 to Lundberg issued Apr. 15, 2008, discloses a polishing and grinding machine for treating concrete, terrazzo, stone and similar surfaces. Gangs of polishing heads treat concrete and similar surface flooring.

U.S. Pat. No. 7,481,602 to Lampley issued Jan. 27, 2009, discloses a diamond trowel blade with diamond particles that can attach to a power trowel for surface preparation of hardened surfaces.

U.S. Pat. No. 7,506,644 to Park issued Mar. 24, 2009, discloses a rotatable grinding wheel, with abrasive segments detachably connected to a disc.

U.S. Pat. No. 7,530,762 to Reed issued May 12, 2009, and U.S. Pat. No. 7,775,741 to Copoulos issued Aug. 17, 2010, disclose methods and apparatuses for surface finishing cured concrete floors using a riding trowel to which large diameter pans are attached.

U.S. Pat. No. 7,815,393 to Snyder issued Oct. 19, 2010, discloses an assembly for rotatably mounting a surface processing tool holder on at least one motor driven rotatable arm of a surface processing apparatus.

U.S. Pat. No. 9,174,326 to Ahonen issued Nov. 3, 2015, reveals a rotatable floor conditioning device. The instrument comprises a porous washing, polishing, and waxing disk for surface treatment.

U.S. Pat. No. 10,011,999 to Tchakarov issued Jul. 3, 2018, a floor finishing apparatus including a grouting pan configured to be affixed to the rotating head of a finishing machine.

U. S. Publication No. 2013/0324021 published Dec. 5, 2013, discloses an abrasive pad for use on hard surfaces that includes a fibrous, non-woven body with an abrasive coating containing diamond-impregnated abrasive elements.

U. S. Publication No. 2018/0369981 published Dec. 27, 2018, discloses a concrete floor trowel machine with blades equipped with a floor polishing jacket or attachment. The attachment may comprise pucks attached with metallic hook-and-loop means.

Another polishing trowel, known as the Velox T-2440 trowel, is revealed at:

• • https://www.diamaticusa.com/products/grinding-polishing-machines/velox-power-trowel/.

Over the years the art has continued to develop, as surface both treatment techniques and the corresponding finishing equipment hardware have evolved significantly. One problem with conventional trowels powered with internal combustion engines relates to their emissions. Many modern large-scale buildings such as warehouses and “big block” buildings enclose thousands if not tens of thousands of indoor concrete surface areas that require substantial finishing during construction.

When used indoors, gasoline or diesel-powered trowels output significant emissions, that besides comprising known health hazards, can be irritating and obnoxious if not toxic. Moreover, reduction of such emissions is of obvious importance vis-a-vis the global warming situation. Consequently, activity with electric concrete finishing machines has grown significantly.

Examples of known electrically powered finishing tools and/or polishers include U.S. Pat. Nos. 5,102,258, 5,632,570, 7,815,393, 8,757,925, 10,584,499, and 11,286,677.

U.S. Pat. No. 10,370,863 issued Aug. 6, 2019, shows another polishing arrangement involving the retrofitting of abrasive components to the spider arms of a rotatable spider assembly of a trowel. A rigid mounting bracket has a somewhat rectangular handle for removably attaching the adapter to the trowel spider arm. The generally planar main body of the bracket is circumferentially offset behind the handle for positioning friction disks behind the trailing side of the rotating spider arm. The friction disks support a plurality of usually rotatable “pucks” that contact and grind against the lower concrete surface for polishing. The whole purpose of the disclosed device is to retrofit conventional trowels, particularly motor-powered, multiple-rotor riding trowels, for use in the final stages of grinding and polishing concrete surfaces.

U.S. Pat. No. 11,326,359 issued May 10, 2022 and assigned to Allen Engineering Corporation, discloses an adaptor for retrofitting to a conventional riding trowel rotor, enabling the trowel to function as a polisher. A large, rigid, circular adaptor disk supports a plurality of smaller, spaced-apart, polishing rotors that project into contact with the concrete surface being treated. A plurality of radially spaced apart, downwardly projecting, diamond-equipped pucks projecting from the polishing rotors frictionally bear against the concrete surface for abrading and polishing in response to the rotating trowel rotors.

Other Allen Engineering patents of interest include U.S. Pat. No. 5,613,801, issued Mar. 25, 1997, that discloses a power riding trowel equipped with a separate motor for powering each of two rotors. Steering is conducted with structure similar to that depicted in expired Allen U.S. Pat. No. 5,108,220. U.S. Pat. No. 5,890,833 entitled “Hydraulically controlled riding trowel” issued to Allen Engineering Corporation Apr. 6, 1999 discloses a high performance, hydraulic riding trowel using a joystick system that controls steering, propulsion, and blade pitch. U.S. Pat. No. 6,089,786 entitled “Dual rotor riding trowel with proportional electro-Hydraulic Steering” issued Jul. 18, 2000, and U.S. Pat. No. 6,053,660 issued Apr. 25, 2000 and entitled “Hydraulically controlled twin rotor riding trowel” disclose joystick-operated, twin rotor riding trowels. The joystick system therein discussed may be similar to that employed in the instant invention. For purposes of disclosure, U.S. Pat. No. 11,326,359 and the others mentioned herein are hereby incorporated by reference as if fully set forth herein.

SUMMARY OF THE INVENTION

This invention provides electric concrete finishing machines for polishing concrete surfaces. Both walk-behind and riding trowel versions are contemplated. Downwardly projecting rotor assemblies, somewhat similar to prior art gasoline or diesel-powered trowel rotors are employed.

Suitable polishing heads that project into contact with the concrete being treated are driven by electric motors which are battery-powered. A plurality of radially spaced apart, downwardly projecting, diamond-equipped pucks may be secured beneath the rotors to frictionally bear against the concrete surface being treated. A variety of puck mounting systems exist, such as that depicted in U. S. Publication No. 20210047845, published Feb. 18, 2021, and U.S. Pat. No. 11,326,359 issued May 10, 2022, the disclosures of which are both incorporated by reference herein. Preferably a quick connect arrangement is used herein; it comprises a rigid drive ring that removably receives and anchors a lower support plate that in turn supports lower abrasive rotors.

Hydraulic circuitry that is electrically controlled by joysticks facilitates steering by tilting the rotors. Hydraulic pressure is obtained from a suitable electric pump. Polishers may be equipped with either one or more electric, battery-powered motors.

Thus, a fundamental object of the invention is to provide an electric polisher for concrete surfaces.

A basic object is to reduce obnoxious hydrocarbon emissions, and to reduce pollution.

A further object is to provide an electric polisher that is joystick-controlled.

Another object is to provide a concrete polishing system of the character described that minimizes the number of heads or “pucks” required.

Another important object is to enable an electric polisher for enhanced surface polishing while maintaining reliable, precision steering characteristics.

These and other objects and advantages of the present invention, along with features of novelty appurtenant thereto, will appear or become apparent in the course of the following descriptive sections.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following drawings, which form a part of the specification, and which are to be construed in conjunction therewith, and in which like reference numerals have been employed throughout wherever possible to indicate like parts in the various views:

FIG. 1 is a front, isometric view of our new polisher;

FIG. 2 is a rear isometric view of our new polisher;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is an enlarged, fragmentary isometric view showing the preferred controller;

FIG. 7 is an enlarged, isometric assembly view detailing the preferred driver plate construction and the abrasive pucks;

FIG. 8 is an exploded isometric view of the electric drive train;

FIG. 9 is a schematic block diagram of the control electronics; and,

FIG. 10 is a hydraulic schematic showing steering components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the accompanying drawings the reference numeral 20 denotes an electric polisher constructed in accordance with the teachings of the invention. The above discussed Allen Engineering Corporation patents, including specifically U.S. Pat. No. 7,690,864 issued Apr. 6, 2010 and entitled “Hydraulic Riding Trowel With Automatic Load Sensing System,” are hereby jointly incorporated by reference, as if fully set forth herein, for purposes of disclosure.

As is known in the art, surface preparation may begin with panning when the concrete is plastic. Typically, panning graduates to blading as concrete cures during the subsequent hardening stages, as is recognized in the art. However, as this technology has evolved over the years, it has become increasingly common to subject the concrete surface to further processing beyond mere “blading” by polishing it to a very fine, smooth surface.

The polisher 20 described herein is of the “ride-on” type, comprising at least a pair of rotors for surface treating that may be tilted as known in the art for steering. However, the teachings herein may be adapted for “walk behind” versions of the polisher comprising only one rotor. Jointly referencing FIGS. 1 and 2, an operator (not shown) comfortably seated within seat assembly 23 (FIG. 1) can operate polisher 20 with a pair of easy-to-use joysticks 26, 27 respectively disposed at the operator's left and right side. Details for the joystick controls are illustrated profusely in one or more of the above-referenced Allen patents. Throttle control, for actuating rotors, is effectuated by potentiometers 31 that are accessible from seat assembly 23 located atop the frame assembly 34FIG. 2). A pair of spaced-apart rotor assemblies 36 (i.e., FIG. 8) dynamically coupled to the frame extend downwardly into contact with the concrete surface 22 (FIG. 1) as is well known in the art. Optional dolly wheel assemblies 33 (i.e., FIG. 2) can be quick connected or disconnected from the polisher for transporting it to a surface region to be treated at the job site.

Each rotor assembly is independently, pivotally suspended from the polisher 20 with pivot brackets 40 (FIG. 8) that tiltably suspend the rotors. This structure is detailed in several of the above-mentioned patents. Preferably, each rotor assembly is driven by a separate electric drive motor 42 (FIGS. 7, 8) driven via a controller 152, 154 (FIG. 9) at least one of which is protectively caged within shroud 52 that is side mounted at an acute angle. Power is supplied by a forty-eight-volt battery pack preferably disposed beneath seat 23 in compartment 53 (i.e., FIGS. 3, 6), The self-propelled ride-on polisher 20 is designed to quickly and reliably finish extremely large areas of concrete surface 22 powered by batteries, electric power from which is routed through suitable controller circuits described below.

Referring to FIG. 10, a suitable half-horsepower electric drive motor 182 powers hydraulic motor 189 for powering the rotor tilting circuitry 179 (FIG. 10). Details of the rotor pivoting function and mounting assemblies are illustrated in the previously referenced Allen patents. Rotor pivoting may be mechanically enabled by twin pivot rods 51, 54 (FIG. 7). As described repeatedly in the aforementioned riding trowel patents, steering is effectuated by tilting the rotors with hydraulic cylinders 55 (FIG. 6). In FIG. 10 the tilting circuit 179 receives hydraulic pressure hydraulic pump 189 that powers the left hand steering control circuit 181 and the right hand steering control circuit 183. A pair of hydraulic tilting cylinders 184 and 185 effectively tilt the rotors to provide forward-reverse steering. Hydraulic cylinder 188 tilts a single rotor to provide left-right polisher steering.

A plurality of radially spaced-apart abrasion rotors in the form of puck-wheels 60 (FIGS. 7, 8) riding on the concrete surface below are driven by and rotated with each rotor. Electric motors 42 operate the rotors. The motors are mounted to a generally circular drive ring 70 that comprises several spokes 73 integrally extending to an outer, peripheral reinforcement ring 72. Fasteners 76 (FIG. 7) secure a puck-wheel support plate 80 to drive ring 70. Details of various hydraulic circuits, circuitry interconnections, and control apparatus are disclosed below.

In FIG. 8 it is seen that a tilt bracket 82 is fastened to motor 42, and mounted within pivot bracket 40. Motor 42 is secured to inner ring 86 of drive ring 70 through concentric spacer 84. Each of the spokes 73 may include an elongated, rigid reinforcement arm 88 adapted to flushly seat within and be nested by the radially spaced apart support channels 89 defined upon support plate 80 and secured by the fasteners 76. Thus, removal of fasteners 76 frees the support plate 80 for removal. Through this quick-connect construction a different abrasion apparatus such as a pan may be quick connected to drive ring 70 if the pan were provided with radially spaced apart channels resembling channels 89. Alternatively, after removal of support plate 70 and installation of an alternative support plate carrying different abraders, different abrasion tools may be employed.

A plurality of radially spaced apart abrasion rotors 60 (FIGS. 7, 8) are rotatably attached to the polygonal support plate 80 and support friction pucks that contact the lower concrete surface. There are preferably four radially spaced apart abrasion rotors 60 secured beneath plate 80. A plurality of radially spaced apart mounting channels 89 can receive and seat spokes 73 of the drive ring 70. Each abrasion rotor 60 has a rigid frame portion 102 (FIG. 8) to which a bearing mount 103 is secured. Bearing housing assembly 104 receives the mount 103 to secure the abrasion rotors 60. The bottom surface 106 may contain and mount a plurality of abrasive pucks 107 known in the art, or other frictional processing apparatus for polishing concrete, and a variety of commercially available grinding and polishing pucks art may be employed. For example, a variety of abrasion and surface treatment tools, including pads and pucks, are available from the Runyon Surface Prep Company, www.runyonsurfaceprep.com, and these are adapted for surface removal, grinding, honing, polishing and burnishing. As used herein the term “puck” means any of the latter surface-contacting abrasive elements.

FIG. 9 shows the electronic control circuitry that delivers three-phase A/C power to twin electric motors for driving the rotors. Circuit 150 comprises a pair of solid state controllers 152 and 154, both of which comprise a Curtis-brand model 1232SE-5371. Forty-eight volt power is supplied by a plurality of batteries connected in parallel, designated collectively by the reference numeral 156. Power is delivered via line 157 through an emergency stop safety switch 158, a fuse 159 and a key switch 160 to the key switch inputs of both controllers 152 and 154. Line 162 connects to the key switch input of controller 154. Three phase A/C power is delivered through the three outputs “U,” “V,” and “W” from both controllers 152, 154 to the respective motor assemblies designated schematically by the reference numerals 170, 172. Speed is selected with a potentiometer 163 (FIG. 9) that connects to controller 152.

The steering arrangement 180 (FIG. 10) is similar to that described in numerous of the previously cited Allen patents. However, in this electric polisher, the necessary hydraulic pressure for steering is generated by an electric motor 182 that is activated in response to circuit 150 (FIG. 9). The hydraulic cylinders, designated by the reference numerals 184, 185 and 188 (FIG. 10) tilt the rotors for steering as described in detail in the aforementioned Allen patents and others.

From the foregoing, it will be seen that this invention is one adapted to obtain all the ends and objects herein set forth, together with other advantages which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Claims

1. An electric polisher for treating concrete: a frame adapted to be supported over a concrete surface to be treated by at least one rotor;a seat upon which a trowel operator may be comfortably seated;at least one rotor assembly secured to the frame and descending into contact with the lower concrete surface below;hydraulic tilting circuits for controlling each rotor assembly;a pair of joysticks for controlling the hydraulic tilting circuits;a hydraulic pump for driving said tilting circuits;an electric motor for powering said hydraulic pump;an electric motor for revolving each rotor assembly;at least one battery for powering said electric motors;each rotor controlling a circular drive ring;a support plate coupled to said drive ring; and,a plurality of radially spaced-apart abrasion rotors secured to said support plate.

2. The polisher as defined in claim 1 wherein the drive ring comprises radially spaced apart spokes extending to an outer, peripheral reinforcement ring.

3. The polisher as defined in claim 2 wherein said support plate is removably coupled to said drive ring.

4. The polisher as defined in claim 3 wherein the support plate comprises a plurality of radially spaced apart channels adapted to receive at least a portion of said drive ring spokes for mounting said support plate to said drive ring.

5. The polisher as defined in claim 4 further comprising potentiometers for adjusting the speed of the rotors.

6. A ride-on electric polisher for treating a concrete surface: a frame adapted to be propelled over the concrete surface to be treated;a seat upon which a trowel operator may be comfortably seated;a pair least of rotor assemblies secured to the frame and descending into contact with the concrete surface;hydraulic tilting circuits for controlling each rotor assembly to effectuate polisher steering;a pair of joysticks for controlling the hydraulic tilting circuits;a hydraulic pump for driving said tilting circuits;an electric motor for powering said hydraulic pump;an electric motor for revolving each rotor assembly;at least one battery for powering said electric motors;each rotor controlling a circular drive ring;a support plate coupled to each of said drive rings; and,a plurality of radially spaced-apart abrasion rotors secured to said support plate.

7. The polisher as defined in claim 6 wherein each drive ring comprises radially spaced apart spokes extending to an integral, outer, peripheral reinforcement ring.

8. The polisher as defined in claim 7 wherein said each support plate is removably coupled to a drive ring.

9. The polisher as defined in claim 8 wherein each support plate comprises a plurality of radially spaced apart channels adapted to receive at least a portion of said drive ring spokes for mounting said support plate to said drive ring.

10. The polisher as defined in claim 9 further comprising potentiometers for adjusting the speed of the rotors.