A multi-wheel grinder tool provides multiple grinding wheels and polishing pads arranged in a single row, and moving along an edge of a stone slab. The tool is effective for increasing the longitudinal surface area for grinding across the edge of a stone slab. The wheels rotatably grind the edge of the slab while simultaneously moving along the longitudinal axis. As the wheels pass along the longitudinal axis, the pad rotatably engage the edge. The edge of the slab is in contact with each pad from all the wheels. A control wheel is powered by a motor via a gear system and a control axle. Outer wheels are in rotatable communication with the control wheel and run counter to each other. By using multiple wheels, grinding is expedited. The wheels have pads with successive grits. A first pad has course grinding grits. A last pad has fine polishing.

BACKGROUND

Typically, a grinder tool is used to grind and polish slabs a stone, such as marble and granite, through a rotatable grinding wheel that is covered by a polishing pad. The pad typically has a specific grit for the type of stone being worked on and the desired appearance for the stone. The wheel passes along the surface of the stone to create the desired grinding and/or polishing effect. Ideally, the grinder tool has to be used in the most uniform possible manner for the best polishing and for the longest life of the tool itself. This uniformity required many passes over the same surface area of the stone slab to achieve the desired appearance for the slab.

The inventor knew that grinder machines for polishing marble were available with a single grinder head having a radial grinder wheel and an attached pad. Typically, the grinder wheel rotates about a vertical axis while the grinder tools oscillates about its horizontal axis. The grinder tool generally has a curved working surface and therefore the tool working surface is substantially reduced to a constantly changing line.

The inventor was also aware that it was often necessary to grind the edges of a slab of stone. The edges were grinded to chamfer soft edges, create decorative bevels, or form a mating surface for two or more slabs. Through years of experience, the inventor recognized that there were several different kinds and sizes of stone edger tools that were used in the field. One such edger was used for shaping the edge of a stone countertop. This edger had a housing with an internal electric motor and a bit extending below the surface of the housing. In use, the housing rested on the level counter surface while the motor spins the bit and the user guides the bit along the edge of the counter surface smoothing and shaping the edge of the stone counter.

However, the inventor quickly recognized that the problem with this type of edger is that the internal motor makes it heavy and difficult to transport and maneuver over the counter surface. Further, the weight of the motor of the edger causes friction between the lower surface of the housing and the stone countertop as the device moves across the countertop. The friction can cause scratches in the stone's surface. Another problem with this type of edger is that it is relatively expensive to purchase and maintain because of the many moving parts that comprise the gears and internal motor.

The inventor was also familiar with another edger, often referred to as a stone polisher. The inventor had used a stone polisher before, and knew that stone polishers were essential tool for stone workmen. The inventor had often used a stone polisher in the past. The stone polisher is a small hand tool comprising a rotating shaft and wheel able to combine with various bits for etching, polishing, and cutting slab materials such as stone. Stone polishers were generally powered pneumatically or electrically.

The inventor, though, recognized that the problem with using a stone polisher as an edger is that stone polishers do not have housings or other guides for aligning and squaring them with the stone. This makes it difficult to form consistent cuts and profiles in stone edges because the angle of the stone polisher relative to the stone's edge is hard to keep consistent. This can lead to more time spent by the stone workman, which means more expense to finish the stone product.

The inventor decide to fabricate a grinder tool that was lightweight and had a small motor, so that the tool could be carried to the stone slab, rather than the slab having to be moved. The inventor realized that a smaller grinder tool could be effective in making smaller cuts and profiles, especially on the edge of the slab. However, the tool was still too slow and required multiple passes along the edge of the stone slab.

Through trial and error, the inventor realized that the efficiency and effectiveness of polishing stones depended on the number of the wheels and pads that could be carried by the tool. By adding multiple wheels along the tool, the grinding surface area along the longitudinal axis of the edge of the slab was expanded. The inventor also recognized that powering a single central wheel saved energy.

After further trial and error, the inventor added different pads on each wheel. The inventor knew that the grit on each pad affected the speed of the grinding process. The inventor recognized that diamond grinding cup wheels are used in different-roughness grindings. For coarse grinding, the bond may be softer and the diamonds' quality higher, because in this case the diamonds are more easily to become blunt.

The inventor knew that in this case, the diamond grit should be bigger, normally from 35 grit to 50 grit. For this is coarse grinding and big grit can improve the working efficiency of the tool. However, for fine grinding, i.e., polishing, the bond may be harder and the diamonds' quality lower. The inventor knew that this was because the diamonds can last longer and hard bond can also help the precision of the processing. For polishing, the diamond grit is normally between 80 grit to 120 grit, depending on the grinding requirements.

However, the inventor saw that the pads were overheating. The inventor knew that a coolant, such as water was often used while grinding stone slabs. The inventor decided to add a fluid inlet that carried water from an outside water source to the tool. The fluid inlet included tubing that directed water onto the pads during their rotation. The water prevented overheating of the pads and helped maintain the grinder tool at optimal efficiency during operation.

Stone grinder tools have been used for economically and efficiently polishing marble and granite in the past, yet none with the present characteristics of the present invention. See U.S. Pat. No. 601,668; U.S. Pat. No. 5,454,751; and U.S. Pat. No. 8,436,624.

For the foregoing reasons, there is a need for a system and method for grinding the edges of stone slabs with a multi-wheel grinder tool that is lightweight and maneuverable.

SUMMARY

The present invention describes a multi-wheel grinder tool that provides multiple grinding wheels arranged in a single row, and moving along a longitudinal axis of an edge of a stone slab. The multiple wheels rotatably grind and/or polish the edge of the stone slab while traversing the longitudinal axis of the edge. Generally, the use of multiple wheels122,124a-ccreates a larger longitudinal surface area along the edge of the slab, which expedites the grinding process. The wheels are covered by polishing pads having progressive grits. As the wheels pass along the longitudinal axis, the pad from each wheel rotatably engages the edge of the slab. In this manner, the edge of the stone slab is in simultaneous contact with each pad from all the wheels.

In some embodiments, the tool is sufficiently small and lightweight, so as to be portable. In this manner, the tool can be carried to the much heavier stone slab, rather than hefting the stone slab to the grinder tool. Also, the generally lightweight disposition of the tool enables a user to manipulate and press the wheels against the edge of the slab.

Those skilled in the art will recognize that the alignment of multiple wheels on the tool exponentially increases the surface area along the edge of the stone slab. For example, when the tool uses four wheels, the grinding capacity is increased by 4×. This increased surface area of grinding wheels not only speeds up the grinding process along the edge of the slab, but also allows for more flexibility in the grinding and polishing process by enabling progressive grits to be used on each successive pad. This increase of grinding surface area through the use of multiple wheels expedites the grinding process. Furthermore, the wheels rotate counter to each other so as to further expedite and enhance the grinding process.

In one embodiment, the tool utilizes a control wheel and a plurality of outer wheels that rotate simultaneously to grind on the edge of the stone slab. The wheels are manually pushed along the longitudinal axis of the edge. The grinding and polishing needs of the slab dictate the amount of pressure to apply on the tool for engaging the wheels thereto. The wheels can be pushed along the longitudinal axis in either linear direction along the edge of the slab. The control wheel and the outer wheels generally align perpendicularly to the edge of the slab, whereby a top surface and a bottom surface of the stone slab are substantially disengaged from the wheels and pads.

The tool is unique in that only the control wheel is powered by a motor. The control wheel rotates in a first direction. The plurality of outer wheels are not independently powered like the control wheel. Rather, the outer wheels are in rotatable communication with the control wheel through a plurality of perimeter teeth. In this manner, a portion of the outer wheels rotate in the same first direction of the control wheel, while a portion of the outer wheels rotate counter to the control wheel in a second direction, depending on their arrangement relative to the control wheel. In one embodiment, two outer wheels are arranged on each side of the control wheel. However, in other embodiments, any number of outer wheels can be arranged relative to the control wheel.

Those skilled in the art will recognize that each wheel is covered with a pad. The pads are used in different-roughness grindings, whereby the grit on the pad determines whether the pad is configured to grind or polish the edge of the slab. In some embodiments, the grit on each pad of the wheels may be progressive. However, in other embodiments, all the wheels may have the same grit. Nonetheless, the grit for each pad is adjustable as needed.

In some embodiments, the tool comprises a support platform that positions across a top surface of the stone slab, adjacent to the edge of the slab. The support platform chiefly serves to carry the tool along the slab, so that the wheels can operate along the edge of the slab. The support platform is defined by an engagement surface having a roller housing that pivots in relation to the support platform to enable manipulation of the wheels and maintenance access. The roller housing pivots on at least one hinge. The roller housing contains a plurality of rollers. The rollers are arranged to roll on the top surface of the slab, perpendicularly to the edge of the slab. The support platform is also defined by a handling surface. The handling surface includes a motor and a pair of handles. Each handle may include a power switch for actuating the motor, as needed. The motor is electrically powered and indirectly powers the control wheel through a pulley. The pulley includes a first pulley end that connects to the motor.

The tool also includes a control portion that perpendicularly joins with the support platform. The control portion contains the gears and wheels used for operation. The control portion orients the wheels generally towards the edge of the slab during operation. In some embodiments, the control portion may include a housing having an access panel. The access panel provides access to a cavity in the housing. The cavity contains a second pulley end of the aforementioned pulley; whereby the rotation generated by the motor simultaneously rotates the first pulley end and the second pulley end. The second pulley end couples to a gear system in the cavity of the control portion. In this manner, the motor actuates the pulley, which in turn actuates the gear system.

The gear system is configured to transmit torque generated by the motor to the control wheel. It is significant to note that the motor does not power the plurality of outer wheels. Rather, the outer wheels are in communication with the control wheel through perimeter teeth. In this manner, energy is saved, as the motor only has to directly operate a single wheel—the control wheel—while the outer wheels rotate off the angular momentum of the control wheel.

A control axle extends transversely through the control portion, between the gear system and the control wheel. The control axle transmits the torque from the gear system to the control wheel for rotation. The control axle passes through a control bushing. The control bushing helps maintain the alignment for the control axle, while a control snap ring helps retain the control axle in the gear system. A plurality of outer axles extend between the gear system and the outer wheels. A plurality of outer bushings maintain the alignment for the outer axles, while a plurality of outer snap rings help retain the outer axles in the gear system. The control axle and the outer axles align along the length of the control portion, inside the cavity of the housing. The respective wheels couple to the ends of the axles for operation.

In some embodiments, a fluid inlet positions on the housing of the control portion. The fluid inlet enables passage of a plurality of fluid lines through the control portion. The fluid lines terminate proximally to the wheels. The fluid lines are defined by a source end and a dispensing end. The fluid lines may carry a fluid, such as water, to sections of the control pad and the outer pads for cooling and lubricating the pads during while they are grinding the edge of the slab. In this manner, each pad may directly receive water while in operation. In one embodiment, a top section of each pad receive water from the dispensing end of the fluid lines. The water flows from the upper section of the pad, and seeps between the edge of the slab and a lower section of the pad to provide the cooling and lubrication.

One objective of the present invention is to provide additional surface area for a stone grinder by including multiple heads that simultaneously rotate along the edge of the slab.

Another objective is to reduce energy consumption by only powering a control wheel and enabling a plurality of outer wheels to rotate off the control wheel through perimeter teeth on the gears.

Another objective is to provide progressive grits on the pads so as to grind and polish simultaneously and create a smoother finish.

Yet another objective is to provide a pivoting roller house to enable the wheels to tilt during engagement with the edge of the slab.

Yet another objective is to provide a lightweight grinder tool that can be carried to the slab manually for grinding the edges without having to move the slab.

Yet another objective is to provide a grinder tool that is inexpensive to manufacture and easy to operate.

DESCRIPTION

One embodiment, referenced inFIGS. 1-6B, illustrates a multi-wheel grinder tool100that provides multiple grinding wheels arranged in a single row, and moving along a longitudinal axis of an edge of a stone slab (not shown). The wheels rotatably grind and/or polish the edge of the stone slab while traversing the longitudinal axis of the edge. The grinding wheels are covered by polishing pads having progressive grits. The tool100may be used for grinding and polishing the edges of stone slabs, such as granite and marble. Though, in other embodiments, the tool100may be used to grind and polish other types of stone and concrete edges.

The tool100operates by simultaneously engaging the edge of the stone slab with a control wheel122and a plurality of outer wheels124a,124b,124c. The wheels122,124a-crotatably grind and/or polish the edge of the stone slab while moving along the longitudinal axis of the edge of the slab. Generally, the use of multiple wheels122,124a-ccreates a larger longitudinal surface area along the edge of the slab, which expedites the grinding process. The longitudinal axis is generally linear and may follow the long end or the short end of the stone slab. The wheels122,124a-crotate counter to each other, so as to further enhance the grinding and polishing effect on the edge of the slab.

In some embodiments, a plurality of interchangeable pads (not shown) cover the wheels122,124a-cto provide a desired grinding or polishing engagement with the slab. As the wheels122,124a-cpass along the longitudinal axis, the pad from each wheel122,124a-crotatably engages the edge. Each pad may have a progressive grit to enable simultaneous grinding and polishing with the edge of the slab as the tool100makes a single longitudinal pass along its edge.

In one embodiment, the tool100is manually pushed, pressed, and pivoted along the edge of the slab. In this manner, tactile senses are used to increase or decrease pressure against the edge of the slab for achieving the desired grinding and polishing effect thereto. However, in other embodiments, a series of progressive pressure springs may be used with each wheel122,124a-c, whereby a spring applies greater pressure for an initial grinding wheel124a, while less pressure is applied by the subsequent polishing wheel124c. In any case, the tool100enables the edge of the slab to be in simultaneous contact with each pad from all of the wheels122,124a-csuch as to increase the surface area of the edge being grinded at any one time.

Those skilled in the art will recognize that the alignment of multiple wheels122,124a-con the tool100exponentially increases the surface area along the edge of the stone slab. For example, when the tool100uses five wheels, the grinding capacity is increased by 5×. If the tool100uses seven wheels, the grinding capacity would increase by 7×, and so forth. This increased surface area of grinding wheels122,124a-cnot only speeds up the grinding process along the edge of the slab, but also allows for more flexibility in the grinding and polishing process by enabling progressive grits to be used on each successive pad. This increase of grinding surface area through the use of multiple wheels122,124a-cexpedites the grinding process. Furthermore, the wheels122,124a-crotate counter to each other so as to further expedite and enhance the grinding process.

As referenced inFIG. 1, the tool100utilizes a control wheel122and a plurality of outer wheels124a-cthat rotate simultaneously to grind on the edge of the stone slab. The wheels122,124a-care manually pushed along the longitudinal axis of the edge. The amount of pressure to apply on the tool100is dependent on the grinding and polishing requirements of the slab. The wheels122,124a-ccan be pushed along the longitudinal axis in either linear direction along the edge of the slab. The control wheel122and the outer wheels124a-cgenerally align perpendicularly to the edge of the slab, whereby a top surface and a bottom surface of the stone slab are substantially disengaged from the wheels122,124a-cand the pads.

The tool100is unique in that only the control wheel122is powered by a motor110. The control wheel122rotates in a first direction. The plurality of outer wheels124a-care not independently powered like the control wheel122. Rather, the outer wheels124a-care in rotatable communication with the control wheel122through a plurality of perimeter teeth148.

In this manner, a portion of the outer wheels124a-brotate in the same first direction of the control wheel122, while a portion of the outer wheels124crotate counter to the control wheel122in a second direction, depending on their arrangement relative to the control wheel122. In one embodiment, two outer wheels are arranged on each side of the control wheel122. However, in other embodiments, any number of outer wheels can be arranged relative to the control wheel122.

Those skilled in the art will recognize that each wheel122,124a-cis covered with a pad. The pads are used in different-roughness grindings, whereby the grit on the pad determines whether the pad is configured to grind or polish the edge of the slab. In some embodiments, the grit on each pad of the wheels122,124a-cmay be progressive. The progressive grits may range from a thirty-five grit to a one hundred-twenty grit, whereby the thirty-five grit is courser for grinding, and the one hundred-twenty grit is finer for polishing. In one possible embodiment, a first outer pad has the thirty-five grit, and a last outer pad has the one hundred-twenty grit. The tool100is pushed in the direction where the thirty-five grit engages the edge of the slab first. However, in other embodiments, all the wheels122,124a-cmay have the same grit. Nonetheless, the grit for each pad is adjustable as needed.

Those skilled in the art will recognize that the control wheel122and the plurality of outer wheels124a-cmay include a diamond grinding cup wheel. The diamond grinding cup wheel is a metal-bonded diamond tool with diamond segments welded or cold-pressed on a steel wheel body, which usually looks like a cup. Diamond grinding cup wheels are usually mounted on stone grinders to grind abrasive building materials like concrete, granite, and marble.

Furthermore, diamond grinding cup wheels are used in different-roughness grindings. For coarse grinding, the bond may be softer and the diamonds' quality higher, because in this case the diamonds are more easily to become blunt. The diamond grit should be bigger, normally from thirty five grit to fifty grit. For this is coarse grinding and big grit can improve the working efficiency of the tool100. However, for fine grinding, i.e., polishing, the bond may be harder and the diamonds' quality lower. This is because the diamonds can last longer and hard bond can also help the precision of the processing. For polishing, the diamond grit is normally between eighty grit to one hundred-twenty grit, depending on the grinding requirements.

In some embodiments, the tool100may sufficiently small and lightweight, so as to be portable. In this manner, the tool100can be carried to the much heavier stone slab, rather than hefting the stone slab to the grinder tool100. Also, the generally lightweight disposition of the tool100enables a user to manipulate and press the wheels122,124a-cagainst the edge of the slab.

In one embodiment, the control wheel122and the outer wheels124a-ceach have a 4″ diameter. This enables the tool100to be about 15-20″ in width. Furthermore, the internal components of the tool100include a small motor110and a simple gear mechanism that does not add significant weight to the tool100, and thus enables portability to the stone slab.

Turning now toFIG. 2A, the tool100comprises a support platform102that positions across a top surface of the stone slab, adjacent to the edge of the slab. The support platform102chiefly serves to carry the tool100along the slab, so that the wheels122,124a-ccan operate along the edge of the slab. The support platform102comprises a roller housing138, having an engagement surface104on which the support platform102moves.

As referenced inFIG. 2B, the engagement surface104of the roller housing138has an opening through which a plurality of rollers106are exposed. The rollers106are arranged to roll on the top surface of the slab, perpendicularly to the edge of the slab. The rollers106shown inFIG. 3Aare aluminum cylinders encased in rubber ridged cylinders. Each aluminum cylinder rotates on a roller axis. The outer rubber surface prevents scratching on the marble. However, in other embodiments, the rollers106may include any mechanism that enables a smooth longitudinal movement of the support platform102on the top surface of the slab.

FIG. 3Billustrates the roller housing138in an operational position relative to the support platform102. From this position, the rollers106carry the tool100across the edge of the slab. However,FIGS. 4A and 4Billustrate the roller housing138pivoting away from the support platform102. In one embodiment, the roller housing138pivots on at least one hinge150. Any type of hinge150known in the art may be used, including, without limitation, a pivot hinge, a barrel hinge, a floating hinge, and a butterfly hinge. The pivoting motion of the roller housing138creates lateral space for the tool100as the wheels122,124a-cengage the edge of the slab. For example, the wheels122,124a-ccan be pivoted up or down while grinding along the edge of the slab to create a bevel on the edge. This capacity to tilt, rotate, and move the wheels122,124a-chorizontally and vertically by pivoting the roller housing138out of the way may especially be useful since the tool100is manual and lightweight. The pivoting motion of the roller housing138also provides access to the cavity120inside a housing116of a control portion114for maintenance purposes.

The support platform102is also defined by a handling surface108. The handling surface108includes a motor110and a pair of handles112. Each handle112may include a power switch (not shown) for actuating the motor110, as needed. The motor110indirectly powers the control wheel122through a pulley128. The motor110may include a small electrical motor having a power outlet cable. Though in other embodiments, the motor110may be powered by a battery. As discussed above, the motor110rotates a pulley128. The pulley128includes a first pulley end130that connects to the motor110. A pulley housing134provides a protective cover for components of the pulley128, such as belts, grooved rollers106, and tensioners.

Looking back atFIG. 2B, the tool100also includes a control portion114that perpendicularly joins with the support platform102. The control portion114contains a gear system140for operation of the wheels122,124a-c. The control portion114securely holds the wheels122,124a-cinto position, orienting the wheels generally towards the edge of the slab during operation. In some embodiments, the control portion114may include a housing116defined by a cavity120and an access panel118. The access panel118provides access to the cavity120. The cavity120contains a second pulley end132of the aforementioned pulley128; whereby the rotation generated by the motor110simultaneously rotates the first pulley end130and the second pulley end132. The second pulley end132couples to a gear system140in the cavity120of the control portion114. In this manner, the motor110actuates the pulley128, which in turn actuates the gear system140.

As referenced inFIG. 5, the gear system140is configured to transmit torque generated by the motor110to the control wheel122. It is significant to note that the motor110does not power the plurality of outer wheels124a-c. Rather, the outer wheels124a-care in communication with the control wheel122through perimeter teeth148. In this manner, energy is saved, as the motor110only has to directly operate a single wheel—the control wheel122—while the outer wheels124a-crotate off the angular momentum generated by the control wheel122.

As illustrated inFIG. 6A, a control axle136extends transversely through the control portion114, between the gear system140and the control wheel122. The control axle136transmits the torque from the gear system140to the control wheel122for rotation. The control axle136passes through a control bushing142. The control bushing142helps maintain the alignment for the control axle136, while a control snap ring (not shown) helps retain the control axle136in the gear system140.

A plurality of outer axles144extend between the gear system140and the outer wheels124a-c. A plurality of outer bushings146maintain the alignment for the outer axles144, while a plurality of outer snap rings (not shown) help retain the outer axles144in the gear system140. The control axle136and the outer axles144align along the length of the control portion114, inside the cavity120of the housing116. The respective wheels122,124a-ccouple to the ends of the axles136,144for operation.

In some embodiments, at least one fluid inlet126positions on the access panel118and sidewalls of the housing116in the control portion114. The fluid inlet126enables passage of a plurality of fluid lines (not shown) through the control portion114. The fluid lines terminate proximally to the wheels122,124a-c. The fluid lines may include rubber hoses that pass through the cavity120of the housing116. The fluid lines are defined by a source end and a dispensing end. The source end may be connected to a water line or a pump on the control portion114. The dispensing end may include an adjustable nozzle. The fluid lines may carry a fluid, such as water, to sections of the control pad and the outer pads for cooling and lubricating the pads during while they are grinding the edge of the slab. In this manner, each pad may directly receive water while in operation.

In one embodiment, a top section of each pad receive water from the dispensing end of the fluid lines. The water flows from the upper section of the pad, and seeps between the edge of the slab and a lower section of the pad to provide the cooling and lubrication. The roller housing116, shown inFIG. 6B, helps maintains a smooth movement of the tool100along the edge of the slab, such that the water engages the pads and the wheels122,124a-c.

While the inventor's above description contains many specificities, these should not be construed as limitations on the scope, but rather as an exemplification of several preferred embodiments thereof. Many other variations are possible. For example, the voltage or current input/output of the motor110may vary without affecting the rotation of the control wheel122. Accordingly, the scope should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.