Patent Application
20230032463
This invention relates generally to concrete grinding and polishing and, in particular, to a grinder/polisher with removably attachable slurry or dust collection accessories.
Polished concrete floors are becoming increasingly popular for retailers, big-box stores, educational and medical facilities, and even residential applications. Common uses include warehouses and warehouse outlets, hotels and restaurants, office buildings and showrooms. Benefits include low cost, resistance to wear, low maintenance, and aesthetic appeal in many situations. Polished concrete floors are easy to clean, and the glossy surface of polished concrete resists the marks of forklift truck tires and staining from oil and chemical spills. The glossy appearance of polished concrete is desirable for office building, hotels, restaurants, and other public facilities that want to project a bright, clean, professional image.
Various different types of machines are used to achieve a polished concrete floor, including riding and walk-behind coarse and fine grinders and polishers using wet and dry techniques. Machines are also available for stripping and removing old floors, filling in cracks, applying concrete overlays, as well as slurry and dust collection.
The polishing process itself proceeds through a series of mechanical and grinding stages utilizing professional equipment designed for these purposes. The process may also include the use of a concrete “densifier” which penetrates into the concrete to harden and dustproof the surface. The concrete surface is processed through a series of steps with grinding and polishing disks having progressively finer grits. The disks are typically fabricated with industrial diamonds in a bonded material such as metal, resin or a combination thereof, often referred to as “diamond polishing pads.”
Typically the concrete goes through a process of grinding and polishing using aggressive equipment and abrasive elements or tooling, including pads of varying grit from 30 to 3,000. Concrete is considered “polished” until grits of 800 or finer are used, followed by finishing to 1500 3000-grit levels. The concrete may be ground without entering aggregate layers, or different sizes of aggregate may be exposed and polished to achieve different appearances. Dyes designed for concrete polishing are often applied to add color to polished concrete for borders, logos and decorative patterns. Such options provide a wide range of surface finish and color variations.
Concrete grinding and polishing begins with grinding pads or tools that have grits of 30, 70, and 120, which are used successively. These abrasive elements are rotated at a relatively slow speed during the grinding steps, e.g., at rotating speeds in the range of about 500 to 800 rpm. After grinding with the diamond pads, honing steps follow using grits of 50, 100, and 200, rotated at, for example, a speed of about 800 rpm. After about 200-grit honing step, dies or stains may be applied and, if necessary, a concrete densifier may be applied to the floor.
Polishing continues using a 400 grit or finer pad, with rotational speeds of the spindles and abrasive elements being in the range of about 800 to 1,100 rpm. The concrete will begin to develop a sheen, with the grit choice of the final polishing steps being dependent upon the reflection and shine desired. If the polishing process is continued through use of a 3000-grit pad, the concrete will assume a mirror-like finish. Burnishing may further promote a specular appearance. A topical sealer may be optionally applied to the finished floor.
The grinding and polishing steps may be dry or wet. With the latter, a water tank on-board the grinding/polishing machine delivers water to the diamond pads or resin pads through channels to the polishing head. With wet polishing, the generated slurry is collected with a squeegee, and with dry polishing the dust is collected with a vacuum. Typically, the polishing head is enclosed with a shroud that surrounds the rotating pads. A vacuum port is connected with a hose to an externally-provided vacuum, which may be nearby or wheeled alongside the grinding and polishing machine.
Although wet and dry techniques both have advantages and disadvantages, dry polishing tends to be faster, more convenient, and environmentally friendly. Wet polishing uses water to cool the diamond abrasives and eliminate grinding dust. The water acts as a lubricant to reduce friction, but cleanup is more involved. Wet polishing creates a tremendous amount of slurry that crews must collect and dispose of in an environmentally sound manner. With dry polishing, no water is required. Instead, the floor polisher is hooked up to a dust-containment system that vacuums up the mess.
In summary, the process of concrete floor polishing may include some or all of the following steps:
This invention simplifies and therefore expedites floor grinding and polishing by providing a walk-behind grinder/polisher equipped with all structural and functional hardware needed to receive removably attachable debris collection modules. These modules are substantially rigidly attached to the frame of the grinder/polisher and suspended above a floor surface so as to travel with the grinder/polisher when coupled thereto.
The system may broadly attach to either a (wet) slurry collection module or a (dry) dust collection module. In each case, the debris collection module removably attaches to a vacuum producer mounted on the frame of the grinder/polisher.
The grinder/polisher includes an engine such as a propane engine mounted on the frame. In preferred embodiments, the engine drives a first hydrostatic pump in fluid communication with a first hydraulic motor driving the grinding/polishing head in reversible fashion. The engine further drives a second hydrostatic pump in fluid communication with a second hydraulic motor driving the vacuum producer.
The dust collection module has an inlet removably attachable to the dust collection port on the shroud, and an outlet coupled to a dust collection canister. The slurry collection module has an inlet removably attachable to a squeegee, and an outlet coupled to a slurry containment vessel.
As mentioned in the Background of the Invention, concrete grinding and polishing may use wet or dry processes. Wet polishing creates a tremendous amount of slurry that crews must collect and dispose of in an environmentally sound manner. With dry polishing, no water is required, but the floor polisher must be hooked up to a dust-containment system that vacuums up the mess. Typically, the polishing head is enclosed with a shroud that surrounds the rotating pads. A vacuum port is connected with a hose to an externally-provided vacuum, which may be nearby or wheeled alongside the grinding and polishing machine.
Thus, both wet and dry grinding and polishing processes require ancillary equipment to suction or vacuum the removed material. This is inconvenient, requiring hoses and connections between the equipment. Moreover, these hoses and connections often get covered in slurry or dust and further complicate the cleanup process.
This invention solves such issues with the prior art by providing a modular wet/dry grinding/polishing machine to which a slurry suction or dust vacuum unit may be removably attached, thereby eliminating the need for separate equipment and the connections therebetween. In the preferred embodiments, the machine is a propane-powered walk-behind unit with a true planetary grinding/polishing head.
Before presenting detail drawings of the machine and attachments,
Motor 120 drives a hydrostatic pump 140 which in turn powers hydraulic motor 142. Motor 142 is coupled to pad 103 containing grinding/polishing elements 105. The invention may be used with removable/replaceable diamond elements or resin-bonded elements of any grit intended for wet or dry grinding or polishing. Motor 142 may be coupled to pad 103 through device 143 which may represent a gear box, lovejoy coupler, or the like. Pad 103 is surrounded by shroud 108 including a dust evacuation port 170. When wet processing is used, elements 105 are cooled and lubricated with water from tank 112 through line 110.
Being hydrostatic, pump 140 may be operated in either direction. Indeed, control 202 facilitates two forward speeds, neutral and reverse. The setting of control 202 causes fluid to flow to or from reservoir 130 through hydraulic lines 134, 135, 137, to set the speed and direction of pad 103 (or no rotation in the neutral position).
Coupled to hydrostatic pump 140 is a smaller, unidirectional hydraulic pump 150. Pump 150 controls the operation of hydraulic motor 152 which, in turn, drives vacuum producer 160. Any coupling may be used, including direct, gears or pulley 162 as shown. Vacuum producer 160 includes an input 164 and output 166. Inlet connection 164 may accommodate a 2″ hose, though other sizes may alternatively be accommodated.
Control 204 enables an operator to turn the vacuum producer 160 ON and OFF. In one position, fluid flows from pump 150 through motor 152 through lines 208, 206, while, in the other position, fluid is routed back to pump 150 through line 207, bypassing motor 152. Note that, in the preferred embodiment, motors 142, 152 may be bent-axis hydraulic motors with the understanding that other motor types may alternatively be used.
Unit 200 in this embodiment makes a connection to the vacuum producer 160 through hose coupling 201. The opening 170 to the shroud 108 would be blanked off. The vacuum is coupled to slurry tank 402 through conduits 414, 412, which preferably includes a visualization gauge 410 enabling an operator to see if any unwanted liquid may be entering the on-board vacuum system. Containment vessel 402 is further coupled to a walk-behind slurry collection squeegee 413 through hose 408. Squeegee 413 conveniently hangs on the back of the frame of the main unit 100. Tank 402 further includes a ball valve 403 enabling the slurry to be discharged and disposed of. Note that the equipment may continue uninterrupted operation immediately after emptying the tank 402.
Dust from the abrasive elements 105 first enter a prefilter 312, followed by a HEPA filter 310. HEPA filter 310 contains a cartridge in a canister which is removed and disposed of. To clean prefilter 312, the line 406 from the polishing head is blanked off with valve 407, and handle 311 is moved to empty the contents of the prefilter into disposal bag 404. The canister associated with prefilter 312 may also be opened to removed and replace the filter cartridge. As with the slurry vacuum attachment, following cleaning the system may resume normal operation.
While
During operation of the grinder/polisher machine, weights 116 on both sides are positioned forwardly onto bumpers 118, transferring weight to the grinding head. To change the pads or grinding/polishing elements, however, the weights are moved back as shown, making it easier to tilt the machine back on caster wheel 210. Caster wheel 210 in
This application claims priority to, and the benefit of, U.S. Provisional Patent Application Ser. No. 63/226,274, filed Jul. 28, 2021, the entire content of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63226274 | Jul 2021 | US |
