PATENT DOCUMENT

Abstract:
A wheeled trolley carries various tools across an object to be worked. A track attaches directly to the work and simultaneously isolates the tool from the work. A standard connection to the trolley readily accommodates a variety of diverse tools, using a keyway or the like to ensure accurate and repeatable placement of the tools. A preferred contouring guide allows a tool to be moved through an arc, where the focal point of the arc may be set to produce an infinite variety of custom shapes, bevels or angles of cut. An upper stop is provided which readily sets the break line between surface finish and edge contour. An adjustable tool carriage allows control over both position and force, including preloading a work tool with force. Resilience is incorporated into the apparatus to accommodate diverse hardness and abrasion characteristics, and, in at least one embodiment, to enable the track to accurately follow a warped or sagging work piece.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 10/081,965 filed Feb. 20, 2002 Now U.S. Pat. No. 6,712,061 presently allowed and copending herewith and listing the present title and inventor, and which in turn claims priority to U.S. Provisional patent application Ser. No. 60/269,721 filed Feb. 20, 2001, the contents of each which are incorporated by reference in entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention pertains generally to the field of stoneworking, and more specifically to sawing, shaping and polishing of stone or similar material. Various specific manifestations of the invention include a portable tool mount which is configured to support and guide a saw, an abrading rotary disk tool, or other stoneworking equipment or tools; an edging apparatus for stone and other hard materials; and a rotary disk abrading tool provided with a member or a holder to facilitate the application of the tool to the workpiece. 
     2. Description of the Related Art 
     Stoneworking is a very old art, dating back to the days of cave dwellers when man is presumed to have first taken shelter within a stone structure. However, the age of the art should not be confused with the level of technology in use today. The desirability of stone in dwellings, for various monuments and markers, and in many other applications continues to be great, owing to intrinsic hardness and resistance to the elements, a wonderful array of diverse natural and enhanced appearances, temperature resistance, thermal mass, low thermal expansion, and other desirable and unusual features. In addition to natural stone, synthetic or artificial stone, stone-containing materials, or stone-like materials are also being manufactured for desired characteristics. Consequently, much modem technology has been applied to further the provision of stone into the marketplace. 
     Natural stone is quarried in large blocks from mines and is normally next cut into thinner slabs. These slabs are polished on one surface and then typically sold into commercial or construction applications. Exemplary construction applications, though not by any means all-inclusive, are wall surfaces and decorations for both interior and exterior, trim, fireplaces, flooring, table tops, and counter tops. Rarely will the polished slab have the exact dimensions required for a given project. Consequently, the slab must be cut to fit the application. Depending upon the application, once the slab has been cut, the edge may additionally need to be finished, which may include leveling, shaping and polishing steps. Shaped and polished edges are typically created by grinding the surface with increasingly finer grits of abrasives. The abrasives are normally cooled with a fluid, typically water. As is known in the industry, the cutting, shaping and polishing operations release a large quantity of abrasive in the form of slurry and dust which can be quite detrimental to machines and equipment which are not designed to withstand the erosive environment. 
     Where large quantities of natural stone or stone-like materials are to be cut and polished, relatively massive equipment has been designed and constructed which facilitates the cutting and polishing operations. These machines are generally designed to have enormous mass, which makes the tools much more rigid and also less susceptible to vibration and flexure that may otherwise occur. While these tools are well suited for operations where stones may be readily transported to the machine, they clearly have no utility for stones to be worked in situ at a construction location or the like. Furthermore, these machines tend to be extremely expensive, and so custom production on this type of machine results in undesirably large amounts of very expensive idle time. Not only do stones need to be changed for custom production, but the machine will also typically require reconfiguration and/or realignment for the custom job. Furthermore, the transport of a stone to and from a construction site to effect the custom work is not only expensive and the source of much delay, but the likelihood of an accident which destroys the stone is much greater with the additional transport. Finally, these large machines tend to be cost-prohibitive for a smaller shop that is not continuously using the machine. Exemplary patents that illustrate large commercial stone working machines include Adams in U.S. Pat. Nos. 3,164,144; 4,228,617 to Bando; U.S. Pat. No. 5,482,026 to Russell; U.S. Pat. No. 6,006,735 to Schlough et al; U.S. Pat. No. 6,073,621 to Cetrangolo; and U.S. Pat. No. 6,315,799 to Toniolo. 
     In an attempt to provide a more portable machine, which may, for example, be used directly at a job site, other artisans have proposed various rail systems which are clamped or otherwise anchored to stone or other hard material, such as concrete or glass. These rails may act as guides, such as in the U.S. Pat. No. 2,014,229 to Emmons; U.S. Pat. No. 4,552,122 to Kelly; U.S. Pat. No. 5,960,780 to Harris; U.S. Pat. No. 6,062,122 to Niemczyk; and U.S. Pat. No. 6,257,225 to Harris; or may alternatively act as a track which supports a trolley or the like. Exemplary trolleys are shown in U.S. Pat. No. 2,291,058 to Pohl; U.S. Pat. No. 3,323,507 to Schuman; U.S. Pat. No. 3,360,298 to Stoljarov et al; U.S. Pat. No. 4,054,179 to Destree; U.S. Pat. No. 4,979,412 to Anders; and U.S. Pat. No. 5,588,418 to Holmes et al. An additional device uses a router with a profiled cutter for shaping and polishing edges. The profiled cutter is an abrasive, and is generally extremely expensive. With the nature of grinding, the abrasive on the profiled cutter is lost, generally unevenly. Consequently, a profiled cutter loses its shape with use and creates an edge which varies. This edge will not match the profile of the next cutter of finer grit, and so the next cutter will not make full contact to the edge of the stone. To achieve a polished edge, the mason will need to go back and rework spots or regions missed by mismatched profiles. 
     For a single cutting operation, many of these devices have found utility in the industry, and rightly so. Providing a guiding edge for an abrasive saw or other cutter such as is used to cut stone and other hard materials is of much benefit for custom applications or the like as are frequently required at a building site. When a section of flooring or wall requires custom cutting and fitting, it is not always practical or reasonable to expect a stone factory to size the stone to the needs in advance. Moreover, it may not always be possible to accurately predict the dimensions owing to variability such as spacing between adjacent stone and the like. Furthermore, the thickness of adjacent stones may vary somewhat unpredictably, and the leveling of the intersection of the two stones may be a very important finishing operation. 
     Unfortunately, many of these devices are designed for only very light duty. Where guides are used, they tend to lack the necessary resistance to abrasion from the stoneworking dust, and consequently have a limited life only suited for very light duty stone working. These machines also illustrate single tool applications. So, when a stone mason identifies the need for a tool to assist with the guiding of a stone cutting saw, he must purchase a guide for his saw. Later, when he elects to purchase a guide for another stone working tool such as a polisher or an edger, he must then purchase another piece of equipment. This single function tool holding and guiding is not highly desirable, and so many masons will perform all but the most complex or sizeable jobs by hand. As is all too well known, when work is completed by hand, there is much greater risk that the mason will err in the process, and this error is not readily remediated in stone. Consequently, the probability for unsightly imperfections or total loss of valuable stone, and the additional work required to remake a destroyed piece or repair an imperfection provides much incentive in the industry for better tools to reduce the dependence upon hand operations. Additionally, the freehand shaping and polishing is very strenuous and time consuming. 
     In addition to the limitations aforementioned, another shortcoming of the prior art apparatus is the ability to guide and form inside openings and corners such as are typically found in the installation of a kitchen or bar sink within a stone counter top. In order to cut this type of hole with inside corners, it is most desirable to drop the saw vertically onto the stone to begin the cut in a predetermined place. Where the design of the cutting guide requires the saw to traverse from an end or edge of the stone, such a guide will have no applicability to the holes created for sinks. Moreover, adjacent to the sink the stone will frequently be rather narrow. Where this is the case, in the prior art a reinforcement bar has been inserted into a small groove cut into the stone. The reinforcement bar may then be pressed into the groove and typically adhesively secured therein. However, the cutting of the trough must also occur in the middle of the stone, and in this instance a wider than ordinary cutting blade is most desirable, in order to only require a single passage of the tool through the stone in the formation of the trough. 
     What is desired then is a portable apparatus which enables a stone mason or worker of other hard material to purchase a single apparatus which will perform the precise guiding of diverse tools across the hard material. A need furthermore exists for an apparatus which will allow a mason at a job site to form precise inside holes, shapes and polished surfaces. 
     SUMMARY OF THE INVENTION 
     In a first manifestation, the invention is the combination track, trolley, crescent, and stoneworking tool for treating a stone slab. The track has a base with a first surface in contact with the stone and a second surface upon which at least one roller may travel in a path. A ridge extends longitudinally parallel to the path with first and second normal surfaces which extend in a first direction normal to the stone slab and in a second longitudinal direction. The trolley is supported on at least one roller which rolls on the second surface and has a second roller which rolls on the ridge first normal surface and a third roller which rolls on the ridge second normal surface. A tensioning member is movable to vary a distance between the second and third rollers from a first position which holds the rollers tightly against the ridge to a second position which allows the rollers to slide normal to the stone slab. The crescent is supported upon the trolley and has first and second crescent members each forming an arc about an edge of the stone slab. Each crescent member has an inside and an outside. There is additionally a space between the two crescent members within which the stoneworking tool operates. The tool has a tool support carriage for traversing the crescent and carrying the tool therewith along the arc. 
     In a second manifestation, the invention is a portable track and trolley for engaging a material to be worked and subsequently mounting a tool for working the material to the trolley, and then guiding the tool relative to material to be worked. A base has a first surface adjacent to a surface of the material and a second surface opposite thereto for supporting the trolley. A rail extends in a height from the material surface in a first normal direction and has opposed roller surfaces thereon defining a width, and extends longitudinally along a length. A trolley undercarriage has a first plurality of wheels maintaining a load a minimum distance normal to the material surface from the material surface that provide rolling contact between the wheels and the base. The undercarriage further has a second plurality of wheels engaging the rail on opposed roller surfaces. A tool carrier locating member locates a tool carrier relative to the trolley. A tool carrier engaging member operatively retains the tool carrier to trolley after engagement therewith. At least one removable fastener retains tool carrier to trolley. 
     In a third manifestation, the invention is a motor carriage for supporting a stoneworking tool in either an operative position or an inoperative position which is readily moved between the operative position and inoperative position. A sliding holder retains the stoneworking tool within motor carriage. A guide is provided, along which the sliding holder travels during movement. A link is provided between sliding holder and an anchor member of the motor carriage. A release pivots about a first axis and responsive thereto moves the link relative to anchor member and thereby moves the sliding holder relative to the anchor member at a first distance change per degree of rotation. The release pivots about a second axis and consequently moves the link relative to anchor member and thereby moves the sliding holder relative to anchor member at a second distance change per degree of rotation which is less than the first distance change per degree of rotation. 
     In a fourth manifestation, the invention is a guide for shaping, contouring and polishing an edge of a hard material through contact with a tool. First and second crescents wrap angularly about the hard material edge. A tool holder is provided between first and second crescents. A means for moving the tool holder relative to crescents follows an outline of the crescents. A means is also provided for engaging the tool with hard material. 
     OBJECTS OF THE INVENTION 
     Exemplary embodiments of the present invention solve inadequacies of the prior art by providing a portable trolley for carrying various tools, and a track which attaches directly to a stone and which simultaneously isolates tool from stone. A standard connection is provided which can readily accommodate a variety of diverse tools, using a keyway to ensure accurate and repeatable placement of the tools. A preferred contouring guide allows a tool to be moved through an arc, where the focal point of the arc may be set to produce an infinite variety of custom shapes. 
     A first object of the invention is to provide a portable tool guide for stone and other hard materials. A second object of the invention is to greatly reduce the hand labor required to custom finish a hard material. Another object of the present invention is to improve the precision of cutting and polishing operations. A further object of the invention is to provide the guide in a relatively small and compact package. Yet another object of the present invention is to enable rapid tool changes. Yet a further object of the invention is to provide a precision shaper using low cost and durable disc-shaped abrasives, to accurately produce a diverse number of edge profiles. Another object of the invention is the provision of a high quality, precision tool guide which is durable and still manufactured for a low cost. An additional object of the invention is to provide an apparatus that automatically adjusts for abrasive material lost from the cutter. Another object of the invention is to provide a portable apparatus that may be manually controlled or controlled through electrical devices. Another object of the invention is to provide an apparatus that will work surfaces that may be warped or otherwise less than perfectly level. A further object of the invention is to provide a means for rapidly controlling the break line profile between stone surface and stone edge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, advantages, and novel features of the present invention can be understood and appreciated by reference to the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  illustrates a preferred embodiment shaping and polishing attachment designed in accord with the teachings of the present invention in combination with a preferred embodiment track and trolley, also designed in accord with the teachings of the present invention, both from a right side plan view. 
         FIG. 2  illustrates a preferred embodiment tool carriage designed in accord with the teachings of the present invention from a top plan view. 
         FIG. 3  illustrates the tool carriage of  FIG. 2  from a partial cut-away view taken along line  3 ′ of  FIG. 2 . 
         FIG. 4  illustrates the preferred embodiment trolley and crescent of  FIG. 1  from top plan view with tool and tool carrier removed for purposes of illustration. 
         FIG. 5  illustrates the underside of the preferred embodiment trolley of  FIG. 1  from a plan view. 
         FIG. 6  illustrates the preferred embodiment trolley and crescent of  FIG. 1  from a cross-section view taken along line  6 ′ of  FIG. 4 , with tool removed for purposes of illustration  FIG. 7  illustrates a preferred stop for use with the preferred embodiment crescent from a top plan view. 
         FIG. 8  illustrates a second preferred embodiment shaping and polishing attachment designed in accord with the teachings of the present invention in combination with a preferred embodiment track and trolley, also designed in accord with the teachings of the present invention, both from a right side plan view, showing a cut-away illustrating several features of this embodiment. 
         FIGS. 9 and 10  illustrate a preferred adjustable stop for use with the preferred embodiment crescent from opposed side plan views. 
         FIG. 11  illustrates the preferred adjustable stop of  FIG. 9  from a side cross-section view. 
         FIG. 12  illustrates the second preferred embodiment shaping and polishing attachment of  FIG. 1  from a top plan view with the tool removed from the crescents and with jack screws removed, to better illustrate the placement of the height adjustment chain. 
         FIGS. 13 and 14  illustrate preferred jack screws for use with the second preferred embodiment shaping and polishing attachment from a side plan view. 
         FIGS. 15 and 16  illustrate a preferred track stiffener from end and side plan views, respectively. 
         FIG. 17  illustrates a second alternative track stiffener from a side plan view. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Manifested in the preferred embodiments illustrated herein, the present invention provides alternative apparatus for working, shaping, and polishing stone and other hard materials. In the first preferred embodiment portable apparatus  100  for working, shaping and polishing stone and other hard materials, illustrated in  FIGS. 1–7 , a stone slab  10  has mounted adjacent thereto a track  200 . Track  200  will most preferably be clamped directly to stone slab  10  using c-clamps and the like, as is known in the industry, though other methods of anchoring are contemplated herein, including such methods as releasable adhesives, other non-permanent methods of attachment, and even permanent methods where the entire stone is not needed for a project. A significant advantage of the preferred embodiment is the reduced need for clamping along the track. Since stone slab  10  may be typically in the vicinity of twelve feet long, fewer clamps translate into more rapid processing and a more readily used apparatus. Track  200 , which is visible from end view in  FIG. 1 , includes two base sections  202 ,  204 . While in the embodiment of  FIG. 1  these are physically separated sections, those skilled in the art will recognize certain benefits with using a base which is either continuous or which has a webbing or only partial cut-outs between the base sections  202 ,  204 . Among these is an easy access point for a c-clamp that is sure to avoid harms way during machine operation, and added strength. 
     Adjoining base sections  202 ,  204  is rail  215 , which in the preferred embodiment includes horizontal members  216 ,  218  and vertical tracks  212 ,  214 . While reference is made here to horizontal and vertical, those skilled in the art will understand that these only typical orientations, and not limited to such orientations. More particularly, rail  215  extends generally normal to a major surface of stone slab  10 . 
     Onto track  200  a trolley  300  is placed and clamped, as will be described herein below. This combination of track  200  and trolley  300  provides a vehicle for low-resistance movement of a tool support carriage  500  in a guided manner parallel to the longitudinal extension of rail  215 . While in the preferred embodiment rail  215  longitudinally extends along a linear axis, the use of a linear rail  215  is not critical to the invention and other shapes including curves may be provided for. 
     Trolley  300  acts as a support for a tool carrier  400  which is secured thereto. Tool carrier  400  as presently illustrated comprises a pair of crescents  470 ,  480  which are most preferred for the flat abrasive discs used in the preferred embodiment  100 . However, those skilled in the field will recognize that the preferred embodiment trolley  300  is compatible with other structures which are known to mate with circular saws carrying diamond or other abrasive wheels, routers, and other stoneworking tools. Between crescents  470 ,  480  is mounted tool support carriage  500 . 
     As illustrated in  FIG. 1 , crescents  470 ,  480  combine to form a central axis of rotation  12 . Axis  12  will extend parallel to rail  215  and will be centered at the focal point of crescents  470 ,  480 . However, once again those skilled in the field will recognize that it is not essential to form crescents  470 ,  480  into a circular geometry as illustrated, though this geometry is typically the most versatile. Other shapes can be patterned which will change the profile produced from the movement of tool support carriage  500  about crescents  470 ,  480 . 
     As is also illustrated in  FIG. 1 , the movement of tool support carriage  500  about crescents  470 ,  480  is controlled by a cable  490  which extends around knob  491 , around bearing pulleys  492 – 494 , and through groove  486  in crescent  480 . Bearing pulley  494  serves as a tensioning member through the rotation of bolt  496  within a hole threaded into plate  495  which supports pulley  494 . The threading of bolt  496  out of plate  495  acts to drive plate  495  away therefrom, since bolt  496  is prevented from moving by crescent  480 . Since, in the preferred embodiment, cable  490  passes just below the surface of crescent  480 , in a groove cut therein, a plate  497  provides a groove and service access to plate  495 . As is apparent, rotation of knob  491  will cause cable  490 , which is anchored to tool support carriage  500  at pin  537 , to move. This movement will ordinarily be stepwise. In other words, an operator will advance cable  490  by a slight rotation of knob  491 , and then run trolley  300  the full length of track  200 . If necessary, trolley  300  may be passed over track  200  one or more additional times to complete the intended operation. Then the operator will advance knob  491 , and repeat the longitudinal displacement of trolley  300  along track  200 . When the full desired arc of crescents  470 ,  480  has been traversed by tool support carriage  500 , a new abrasive disc  510 , typically of finer grit, will be installed and the process repeated. 
     In one alternative embodiment contemplated herein, the positioning of tool support carriage  500  about crescents  470 ,  480  may be accomplished by a drive roller on the surface of one of crescents  470 ,  480 . The drive roller may then be driven by a knob that shares the same axle shaft. The knob then travels on the motor carriage in the arc of the crescent. Unfortunately, this approach is somewhat less operator friendly, because when the motor carriage is in the 6 o&#39;clock position, the operator&#39;s hand is below the table. The operator&#39;s hand will have to be placed in a different location along the arc of the crescent as the tool is moved about the crescent, so the operator will always have to look to place their hand on the knob. In the preferred embodiment, cable  490  permits knob  491  to be placed in a permanent location on crescent  480 . Consequently, the operator will readily locate knob  491 . 
     A second alternative embodiment contemplated herein is to substitute a chain for cable  490 , also configured in an endless loop. To avoid slippage with respect to cable  490 , the tension on cable  490  must be maintained to create friction on bearing pulleys  492 – 494  or other suitable friction generating device. Additional tension may create undesirable wear in the groove on crescent  480  where the cable travels and on all associated bearings. This second alternative embodiment chain will not slip with respect to a sprocket, and so will generally require less tension. In some instances a chain may also be simpler to repair than a cable. 
     The use of cable  490 , or alternative chain, additionally permits a positioning motor to be substituted for knob  491  and be supported on crescent  480 . This motor might in one contemplated embodiment be placed adjacent counterweight  404  on crescent  480 , which would lessen the weight needed for counterweight  404 , and thereby maintain the weight of portable apparatus  100  unaltered. 
     In the prior art, exemplified by Toniolo in U.S. Pat. No. 6,315,799, the motor carriage is positioned by a means of a positioning motor, rack and pinion. The positioning motor shaft turns a pinion gear or sprocket, which engages a rack or chain that is shaped to match the arc of the crescent. Consequently, the positioning motor must be carried on the motor carriage, and therefore adds more weight to the motor carriage, in turn requiring the crescent to be stronger and heavier and the positioning motor to move additional mass. With this additional weight, the counterweight will also need to be heavier, in turn making the whole apparatus weigh substantially more. Such configuration substantially detracts from the portability desired and achieved in the present invention. 
     Yet another alternative embodiment contemplated herein is the use of an ended loop where the cable ends are captured by a winch pulley or the like, or arranging the cable to be woven into the pulley and fastened to prevent slippage. The limitation of this approach is the requirement for sufficient space and clearance to wind enough cable within the winch pulley to enable full travel of tool support carriage  500  about crescents  470 ,  480 . While such approach will avoid slippage, and consequently permit tension to approximate the aforementioned chain alternative, the direct driving of tool support carriage  500  about crescents  470 ,  480  may also be forfeited. As outlined by the present disclosure, flexible link cable, wire, beaded wire, cleated belt, chain and other similar devices are contemplated as substitutes for cable  490 . 
     A preferred embodiment stop  700  is illustrated in  FIG. 7  which provides one preferred method of controlling the limits of movement of tool support carriage  500  about crescents  470 ,  480 . A threaded bolt  715  may include a flattened head  710  that engages within a T-slot or the like within one or both of crescents  470 ,  480 , though in the preferred embodiment the T-slot is cut into crescent  470  to avoid interference with cable  490  discussed herein below. Hook stop  730  is configured to have an inside diamond-shaped cut-out  735  which corresponds to the outer geometry of crescent  470 , and which can be held tightly there against. Wing nut  720  is provided to thread upon bolt  715  and is used to tighten against hook stop  730 , thereby pulling flattened head  710  tightly against the T-slot of crescent  470 . When the crescent  470  material is pinched between flattened head  710  and hook stop  730 , cut-out  735  will be very resistant to movement along the outer periphery of crescent  470 , and will therefore stop rotation of tool support carriage  500  beyond stop  700 . 
     As tool support carriage  500  traverses crescents  470 ,  480 , cabling and tubing which may supply such things as tool power (i.e.—pneumatic hydraulic or electrical sources or other equivalents), cooling fluid, and the like will need to be supported and kept out of harms way. Hinged arm  580  serves this purpose, by doubling cabling up when tool support carriage  500  is in an upper position such as illustrated in  FIG. 1 , and extending to a straight line when tool support carriage  500  moves down crescents  470 ,  480 . 
     In order to locate the central axis of rotation  12  at a desired elevation, knob  415  on handle  410  has been provided. Handle  410  is rotated, which in turn rotates jack screw  414  visible in  FIG. 6 . This jack screw turns against threads in crescent base  412  to elevate crescent base  412  with respect to tool carrier base  422 . In order for crescent base  412  to move, knobs  430  and  440  must not be tightly engaged with bolts  433 ,  443 , so that these bolts may slide within slots  434 ,  444 . Since jack screw  414  is only driving crescent base  412  from a single location, and could consequently tilt crescents  470 ,  480  that are attached to crescent base  412  undesirably, two linear shafts  450 ,  460  are provided on which linear bearings  453 ,  454  and  463 ,  464  slide, respectively. Linear shaft  450  terminates on top at end  451  and on a lower end  452 , while linear shaft  460  terminates at top end  461  and lower end  462 . 
     While there are a multitude of indexing techniques available in the industry, and the present invention is not limited to a single technique, in the preferred embodiment tool carrier  400  and trolley  300 , two transverse keys  371  and  372  are provided which provide alignment. Additionally, two vertically oriented anchor bolts  360 ,  362 , which are visible in  FIG. 5 , engage with knobs  420 ,  425  respectively to securely anchor tool carrier  400  to trolley  300 . More or fewer bolts, knobs and keys may be provided, depending upon the complexity tolerable for an application and the precision required. Through the use of the present attachment scheme and positional locating, different tool carriers other than tool carrier  400  may be placed onto trolley  300  without the need to relocate track  200 . This can allow an operator to first cut stone slab  10  using a circular saw, and then polish using the tool support carriage  500  of the preferred embodiment while leaving track  200  anchored to stone slab  10 . 
     As is evident in  FIG. 1 , tool support carriage  500  and crescents  470 ,  480  extend to the left of the leftmost wheel  311 , and so may tend to induce tilting of tool carrier  400  relative to stone  10 . This effect may be offset by the force of abrasive disc  510  against stone slab  10  when disc  510  is pressing from above stone slab  10 . Unfortunately, when an operation occurs from the underside of stone slab  10 , the force on abrasive disc  510  adds to the load which could tilt tool carrier  400 . This tilting effect can be mitigated or eliminated through careful selection of weights  404  retained by outer rail  402 . These weights can be set prior to any work, or may be varied during the shaping and polishing, for example to more precisely balance the machine from a top-edge operation to a subsequent bottom edge operation. 
       FIGS. 2 and 3  illustrate tool support carriage  500  in much greater detail. As aforementioned, tool support carriage  500  rides upon crescents  470 ,  480  through wheels  502 ,  504  and  506 . Wheels  502 – 506  are most preferably manufactured from a hard material such as stainless steel or brass, since this prevents the formation of flat spots when wheels  502 – 506  are not being used, particular for long periods of time. During extended periods of non-use, tool support carriage  500  may be stored in the fully clockwise rotation as viewed in  FIG. 1 . This is not a normal polishing or shaping position, and if any flat spots develop in crescents  470 ,  480 , they will not be disruptive to the next shaping or polishing operation. 
     In order to obtain the most preferred friction between crescents  470 ,  480  and these hard wheels  502 – 506 , v-shaped sloped surfaces  472 ,  474  and  482 ,  484  will most preferably be manufactured from a resilient material such as natural rubber or carbon filled rubber. In addition to other benefit, a soft rail is not easily damaged during shipping. However, the use of many different materials is contemplated herein, so long as there is sufficient friction between wheels  502 – 506  and crescents  470 ,  480  to keep tool support carriage  500  firmly anchored thereto. In the preferred embodiment, crescents  470 ,  480  are manufactured from polymers, owing to good strength to weight ratio and intrinsic moisture and abrasion resistance available with appropriate compounds. 
     In one contemplated alternative, wheels  502 – 506  may be designed to be flanged rather than v-shaped, to ride on the inner radius of the crescent. If stone debris lands on the 6 o&#39;clock position on the crescent, the flanged roller may more readily push the debris aside and maintain the desired arc-shaped path. 
     As is visible in  FIG. 3 , lower wheel  506 , which engages an inner circumference of crescent  480 , is supported upon tenon  535  which is inserted into motor carriage  530 . For purposes of discussion, motor carriage  530  will be discussed along with associated components. From  FIG. 2 , however, it will be apparent that motor carriage  540  includes like components and will have like features and characteristics. Screw  561  is used to adjust tenon  535  vertically, which enables a tightening and loosening of wheels  502 ,  504 ,  506  about crescent  480 . In this way, wear, tolerances and the like can be compensated for, and materials having different resilience and friction characteristics can readily be accommodated. In one alternative embodiment contemplated herein, screw  561  may be drilled and inserted from the bottom up, rather than from the top down as illustrated herein. 
     Motor bracket  560  is designed to be adjustable vertically within motor carriage  530 . This movement is achieved through a threaded block  590  and threaded rod  550 . Motor carriage  530  is formed with several vertically extending v-grooves  531 ,  534  which mate with smaller wheels  532 ,  533 . These wheels are held tightly into the grooves by adjustment of screw  559 , which slides wheels  532 ,  556  together along rectangular cut-outs  557 ,  558 . In other words, screw  559  can be tightened to pull wheels  557 ,  558  farther from wheels  533 ,  555  tightly into motor carriage  530  grooves  531 ,  534 . When knob  525  is turned about handle  520 , threaded rod  550  acts as a jack screw, raising or lowering motor bracket  560  within motor carriage  530 . This adjustment is a very gradual adjustment, with only a small change in elevation for a large angular rotation of handle  520 . Once abrasive disc  510  contacts stone slab  10 , further rotation of handle  520  will not move stone slab  10 . Instead, any movement will come through compression of spring  552  and a raising of handle  520  away from abrasive disc  510 . This effects a greater compression of spring  552 , which in turn translates into a greater contact force between abrasive disc  510  and stone slab  10 . Consequently, once abrasive disc  10  is located relative to stone slab  10 , the force applied therebetween may be controlled. 
     An additional feature is provided by making handle  520  rotate not just about the axis of rod  550 , but also swing about an axis transverse thereto. Movement of handle  520  from the position shown in  FIG. 3  to a position co-axial with threaded rod  550  will cause substantial vertical movement of rod  550  and consequently motor bracket  560 . This feature enables an operator to readily remove abrasive disc  510  from stone slab  10  by the simple act of pivoting handle  520  over center about the camming region  522 . Returning handle  520  to the position shown in  FIG. 3  will restore abrasive  510  to contact with stone slab  10 , or whatever position abrasive  510  was in, prior to handle  520  being raised coaxial with threaded rod  550 . This is an important benefit, since an abrasive disc  510  may be changed without losing the depth setting that was in effect at that moment. Shaping or polishing may continue without any recalibration. 
     A washer  523  may be provided to act as a bearing and wear surface for the rotation and camming of handle  520 . In addition, as visible in  FIG. 3 , handle  520  will have a slightly raised or thinned portion  524  which provides adequate clearance between bolt head  528  and the top of motor carriage  530 . Bolt  527  simply attaches knob  525  to handle  520 . 
     Additional force will typically be applied through spring  552 , which extends between washer  553  and washer  554 . For exemplary purposes only, and in no way intending to be limiting to the invention, for differing abrasives it may be desirable to preload the abrasive disc  510  with different forces, which may be measured in the tens of pounds of force. Spring  552  may be preloaded as described herein above to a desired contact force, and consequently serve to control or moderate the forces applied to abrasive disc  510 . 
     Washer  554  is most preferably anchored to rod  550 , and may alternatively be a nut which is threaded onto threaded rod  550 . When handle  520  is cammed, spring  552  will be compressed, tending to pull handle  520  snug against washer  523 . In ordinary operation where spring  552  has not been completely compressed for purposes of preloading, spring  552  acts as a sort of force limiter as well, allowing spring  552  to be compressed if an excessive force is applied against abrasive disc  510 . 
     A fixed depth abrasive process combined with the ability to preload forces onto abrasive disc  510  is a novel combination which offers much utility in the smaller equipment market place. Prior to the present invention, the selection was either a fixed depth with no force loading, or a pneumatic system with a particular force but without fixed depth control. Inconsistent materials which vary in hardness or abrasiveness are extremely difficult to handle with either of the prior art systems, where the present invention is able to accommodate material variations. 
     Most preferably, a commercial, off-the-shelftool rotary tool  570  is used within motor bracket  560 . In the preferred embodiment, tool  570  is sold drilled and tapped by the manufacturer, and bolt  536  serves as the anchor into the commercially provided hole. In addition, and contemplated as but one part of many alternative fastening schemes, adjustable strap  574  is used to also anchor tool  570  to motor bracket  560 . 
     Cooling fluid, typically water, may be provided to abrasive disc  510  and stone slab  10  through spray nozzles  512  and  513  circumferentially, in which case a water inlet  538  with threaded nipple  514  is attached to a water source. Most preferably, water is provided through a center outlet into the middle of abrasive disc  510 , owing to the difficulty of forcing water to move against the centrifugal forces applied by spinning abrasive disc  510 . In association with the formation of a water slurry, it may be desirable to put a seal or rod wiper  576  about rotating shaft  509  as shown in  FIG. 3  to block the slurry from traveling into machine components. It is noteworthy that tool support carriage  500  may be operated in an upside down position, which, without seal  576 , would allow the slurry to run down into any openings within tool carriage  500  to tool  570  and other vital components. Base  507  provides some enclosure for fluid that might climb rotary shaft  509 , but a flexible skirt may also be provided around abrasive disc  510  to help reduce or prevent slurry from being sprayed off of abrasive disc  510 . A small weep hole, not illustrated, may be provided in base  507  to permit any slurry or cooling liquids to pass out of base  507 . This will be particularly beneficial when tool carriage  500  is intended for operation under stone slab  10 . 
       FIG. 5  illustrates trolley  300  from an underneath view looking upwards. Rail  215  will pass between and most preferably be slightly pinched by wheels  320 ,  322 ,  324 ,  326  and  328 . This pinching is effected by rotation of handle  340 , having hand grip  341 , about pivot  343 . The rotation results in a variation in distance between pivot  343  and handle cut-out  332 . In turn pivot  343  either pulls on rod  344  or releases tension therefrom. This in turn pulls on or releases tension from undercarriage  350 , causing undercarriage  350  to move responsive to the position of hand grip  341 . The motion in undercarriage  350  which results is a result of pivot  343  being off center of head  342 . To allow rod  344  to pass through a hole of approximately the same diameter, only very slightly larger, a cut-out  332  in handle  330  is provided which allows for the eccentric motion of head  342 . In the position shown in  FIG. 5 , undercarriage  350  will be drawn through bolt head  345  towards handle  340 . This pulling will additionally work to compress spring  346  within trolley  300 . At the other end of undercarriage  350  distal to bolt head  345 , bolt head  347  may optionally be turned to similarly compress spring  349  by threading bolt  348  into threaded pin  352 . 
     Vertical wheels  314 – 317  are positioned very closely to rail  215 . In the preferred embodiment the placement of wheels immediately adjacent rail  215  is deemed to be important to enable less movement in the event of a serious overload or other unexpected condition. In effect, if any serious overload were to occur, these vertically oriented wheels would be expected to engage with rail  215 , thus preventing any serious destruction from occurring. Wheels  310 – 313  are purposefully placed adjacent the tool, in this case tool support carriage  500 , to reduce the lever effect or moment that is generated when a weight is a large distance from a pivot point. Wheel  318 , which is opposite wheels  310 – 313 , provides a similar balance for oppositely acting forces, such as the application of too much force onto a tool head or the like, which tends to lift closer wheels and put the force on wheel  318 . A weight  404  may be used, as aforementioned, to help balance excessive weights such as an overly heavy tool support carriage  500 . 
     Handles  330 ,  335  are illustrated for trolley  300 , which allows trolley  300  to be moved manually along track  200 . This motion may be effected equally as well via a cable puller or the like, or any machines or mechanisms which obtain the desired goal of transporting trolley  300  longitudinally along track  200 . Other mechanisms may be similarly automated where desired, such as, for exemplary purposes only and not to be construed as limiting in any way, a small motor such as a positioning motor may be provided to control cable  490 . 
       FIG. 8  illustrates a second preferred embodiment portable apparatus  102 . While numbering has been preserved where like components are illustrated, it will be understood herein that these components may take on not only the form illustrated in the figure but also any of the alternative embodiments mentioned herein or known in the field. In this embodiment, tool carrier  400  has been replaced by tool carrier  600 . While both tool carriers perform the same function of raising and lowering the crescent pair  470 ,  480 , slightly different apparatus are used in tool carrier  600 . More particularly, linear shafts  450 ,  460  have been replaced with rectangular bar stock  620 . It will be understood that while only one bar stock  620  is shown, two such components are incorporated in the preferred embodiment, and these are arranged similarly to linear shafts  450 ,  460  as shown, for example, in  FIG. 6 . Nevertheless, the exact number of rectangular bar stock members used is not critical to the operation of the invention, two being preferred to balance each crescent  470 ,  480  while not incorporating excessive cost and component count by adding more than two. Said another way, two have been determined to be adequate, though more or less may be used as desired by a designer without altering the form and operation of the present invention. It will also be recognized herein that bar stock  620  may, in fact, comprise other geometries than the simple rectangular parallelepiped illustrated herein, and instead must function as required and obtainable with bar stock. Linear bearings  453 ,  454  and  463 ,  464  have been replaced by pairs of roller wheels  622 ,  624  which are mounted to and support crescents  470 ,  480  against gravity. Roller wheels  622 ,  624  may be less prone to binding, in the event particles or grit should become lodged against bar stock  620 . The wheel pair will simply pivot slightly and pass over the obstruction. Nevertheless, to reduce the likelihood of such pivoting, various techniques which are contemplated herein may be additionally provided, including but not limited to: the provision of special geometries to control the mating geometry between wheels  622 ,  624  and bar stock  620 ; the use of a cleaning device such as a blade, scraper, wiper or the like leading the movement of each wheel; and/or enclosing bar stock  620  and wheels  622 ,  624  in a dust shield. A second change to tool carrier  600  is in the mechanism used to raise and lower crescents  470 ,  480 . In tool carrier  400 , this is achieved using a single jack screw  414 . In tool carrier  600 , a pair of jack screws  610  are used, one located adjacent each of crescents  470 ,  480 . To synchronize the movement of these jack screws  610 , a chain  613  illustrated in  FIG. 12  couples the two screws together. The use of two jack screws  610  ensures both crescents  470 ,  480  move up and down together. 
     Three additional changes to tool carrier  600  which are visible in  FIG. 8  include the use of a cable and hose support hook  640 , which may of course take on shape or dimension other than shown in  FIG. 8 , the use of adjustable limit stop  700 , described herein below with regard to  FIGS. 9–11 , and also the inclusion of an electrical power switch box  630  adjacent to the top of jack screws  610 . Adjustable limit stop  700  is designed to mount immediately adjacent to crescent  470  and face crescent  480 . Most preferably, a number of discrete faces are provided therein which are designed to be selectively positioned to abut tool support carriage housing  501  when tool support carriage  500  is moved to a fully clockwise travel position as shown in  FIG. 8 . 
       FIGS. 9–11  illustrate adjustable limit stop  700  in much greater detail. This stop  700  will control how defined the break or transition line will appear in the profile. The transition line is where the factory polished top surface ends and the profiled edge begins. As can be seen in  FIG. 9 , a plurality of faces  701 – 706  are preferably provided which tend to progressively increase in distance from pivot shaft  707 . In the preferred embodiment, each face corresponds to a particular angular offset. As shown in  FIG. 9 , these are 0, 2, 4, 6, 8, and 10 degree offsets for faces  701 – 706 , respectively. As may be understood, the transition line is part of the edge profile. The customer who wants the finished stone product is going to choose the type of transition line they want. This line can be very defined, as in a 45 degree bevel or a pencil edge like you would see on glass. The line can also be blended or lost in that it has no defining location like in a bullnose or on quarter-rounds. A zero degree offset will blend the edge of stone  10  formed about axis  12  with the top planar surface, leaving no visible line therebetween. However, for many applications a more distinct line between factory top polish and edge profile is preferred. This visible line is controlled by the minimum angular offset from parallel with the factory top that is permitted, which in turn is controlled by adjustable limit stop  700  through the selection of which face  701 – 706  abuts with tool support carriage housing  501 . 
     On the back side of adjustable limit stop  700  are provided set holes  711 – 716 , visible in  FIG. 10 . As may be best seen from  FIG. 11 , these holes  711 – 716  are designed to engage with index pin  720  to determine which face  701 – 706  will abut with tool support carriage housing  501 . The operator will select a face by pressing knob  726  towards crescent  470  sufficiently to fully remove index pin  720  from hole  711 . Next, knob  726  will be turned, until a selected hole  711 – 716  aligns with index pin  720 . Knob  726  may then be released, locking adjustable limit stop  700  to a desired angular orientation. Adjustable limit stop  700  is retained onto pivot shaft  707  using a recessed nut  708  on a first side, and a jam nut  722  opposed thereto. A return spring  724  is preferably provided to ensure index pin  720  fully engages with the selected hole  711 – 716 . 
     While the preferred embodiment adjustable limit stop  700  illustrates six discrete faces, it will be apparent that other numbers of faces and arrangements may also be provided. For exemplary purposes, but certainly not limited thereto, more or fewer faces may be provided, the offsets may change in other ways rather than gradually increasing as shown, or a continuous spiral may be provided. Nevertheless, for ease of use and rapid alignment, the present index pin arrangement is most preferred. The limited number of choices allow for repeatability in set up. An operator may create the same profiles several days apart if he follows the same stop settings. 
       FIG. 12  illustrates the placement of chain  613  relative to crescents  470 ,  480 , and, as is apparent therein, chain  613  is configured to traverse an endless loop adjacent to each crescent. The relative placement is illustrated schematically in  FIG. 12  with an outline designating chain cover  607  and tool carrier cover  605 . Cable guide  580 , which facilitates the safe guiding of water and power cables to tool support carriage  500 , is also illustrated, as is a convenient location for a water control valve  645 . While water control valve  645  maybe located at any convenient place, placement adjacent chain cover  607  permits ready access to the valve at any time during operations. Similarly, and as visible in  FIG. 8 , electrical power switch  630  may also be located adjacent thereto. Electrical power switch  630  may be a magnetic safety switch or the like to ensure that power is not applied simply by plugging in portable apparatus  102 , but instead must include an operator switch actuation. 
       FIGS. 13 and 14  illustrate the two preferred jack screws  610  that are driven by endless chain  613  to adjust the height of crescents  470 ,  480  relative to stone  10 . Just beneath chain cover  607  in both figures is a chain sprocket  614  used in association with chain  613  to turn jack screws  610 . Bearings  612  are provided which permit the free rotation of jack screws  610  relative to cover  605 .  FIG. 14  additionally illustrates a hand crank  618  coupled to jack screw extension  616 . Hand crank  618  is used to drive chain  613  and thereby effect rotation of jack screws  610 , to in turn adjust the height of the crescents as aforementioned. 
     While a hand knob  618  is illustrated, it will be understood that a motor or other source of drive may be provided for chain  613 . Similarly, other drives may be provided for each of the components, including but not limited to the movement of trolley  300  with respect to tracks  200 ,  201 , the movement of tool support carriage  500  relative to crescents  470 ,  480 , and so forth. One benefit of the preferred portable apparatus  100 ,  102  is the opportunity to control operations either manually or with motors. 
     A preferred feature of either track  200  or track  201  is that the track be sufficiently flexible to follow the surface of a stone and still be rigid enough to handle deflection forces generated by machining the stone. By following the stone, even when slightly warped, portable apparatus  100 ,  102  will be bearing on the stone and preferably remain parallel to the adjacent stone surface. When tracks  200 ,  201  are so designed, the stone or other work piece may be supported easily upon a table, saw horses or the like, without requiring the massive prior art steel beams and tables. For ease of transport by a craftsperson, sawhorses are generally preferred. As is known in the industry, some stones will flex or bend slightly when spanning saw horses. This is especially true for the new synthetic granite that uses a resin product as a binder, or for thinner or longer work pieces. The contour surface of the stone will need to be followed to create a profiled edge that is both uniform and also parallel to the surface of the stone. As trolley  300  is moved along either track  200  or track  201  to a point beyond the end of the stone, the track will be cantilevered beyond the stone to support the machine. The track has to support trolley  300  securely, so that abrasive disc  510  doesn&#39;t snipe or bite deeper in the corner of the workpiece. In other words, tracks  200 ,  201  will preferably be flexible in the center and then rigid on the extreme ends adjacent the stone ends, to support the weight of trolley  300 . Since work pieces often differ in length, the track will most preferably have a way to adjust rigidity to the length of the workpiece. 
     To address this need for both flexibility and rigidity, a first embodiment stiffener  800  is illustrated in  FIG. 15 . As may be seen therein, track  201  has a profile with two t-slots  203 ,  205  that run parallel to its length. The front slot  205  that is closest to crescents  470 ,  480  is underneath the trolley  300  center of balance. In this front slot  205  the operator will slide stiffener  800 , to hold track  201  to stone or other work piece  10 . After clamp  802  is secured, by placing bolts  804  and tightening screw  806  in the preferred embodiment, there is a bracket-like member  808  that pivots about hinge  807  relative to tightening screw  806 . By rotating thumbscrew  809 , bracket  808  will push away from clamp  802 , thereby creating additional support for the end of track  201 . Most preferably, thumbscrew  809  will be rotated sufficiently to make the ends of track  201  beyond work piece  10  rigid enough to support the weight of trolley  300 , while track  201  remains relatively more flexible in the vertical plane normal to the work piece elsewhere, to conform to the work piece surface. 
     Another apparatus used to support a stone work piece  10 , instead of a pair of sawhorses, might be a table. Using a table, stone  10  would be placed on the table so that the stone&#39;s edge is hanging out away from the table&#39;s edge. The operator now can choose between the two t-slots  203 ,  205  for clamping track  201  to stone  10 . The front t-slot  205  could be used as in the saw horse approach already described herein above. However, back t-slot  203  may also or alternatively be used. Back t-slot  203  has a greater cavity height under the ridge, so that a standard F-clamp jaw can fit in this cavity. This F-clamp style comes in many lengths, which allows an operator more flexibility in set-up. With these larger clamp openings, the operator can clamp track  201  to the table. The operator will still need to shore up the extensions adjacent the ends of stone  10  so that abrasive disc  510  won&#39;t snipe the ends. This can be accomplished with stone remnants or some type of device like pop-ups or wedges that can fill this space between the track and table at the ends of the stone. 
     In yet another contemplated embodiment, a dedicated table may be provided. With a dedicated table, track  201  may be provided with more structure in the vertical plane, because the table will control the bending of the stone. A mechanism could then be provided in the table to lift the track from the ends. The stone would be slipped in between the table and track. The track would be lowered to make contact to stone and could utilize the structure of the stone for its bearing and remain parallel to the stone&#39;s surface. This whole apparatus would be quite simpler and more durable to manufacture compared to the heavy machines of the prior art. 
     In the prior art, a carrier that travels in a direction that is parallel to the edge of the workpiece holds the tool adjacent the edge of the workpiece. This carrier travels on a rail that can be on a bridge above the table or a rail that is below the table. Either method requires that the table and rail be perfectly parallel. If not, when doing a small profile like a ⅛″ radius round-over, the profile will noticeably change down the length of the edge. This has become an issue on these large expensive machines, because many work pieces do not fill the machine to capacity. Consequently, the operator tends to work most of the time near the center of the machine. This creates a wear area on the rails in the center of the machine, and the machine can no longer stay within tolerances. Replacement is a significant challenge and expense, not only due to the cost of the large components, but also owing to the need for precise alignment therebetween. When the tracks  200 ,  201  of the preferred embodiments of the present invention show significant wear, the operator may easily replace the track with no new assembly or machining, and alignment is automatic. 
     A second embodiment stiffener  810  is shown in  FIG. 17 . As illustrated therein, a specially shaped body member  818  is slid into either groove  203 ,  205  or both, and screw  806  tightened. The force of screw  806 , owing to the intrinsic geometry of member  818 , will cause member  818  to apply an upward deflection force to track  201 . 
     As illustrated and described herein above with reference to the preferred embodiments, the present invention provides a means to shape and polish a perfect edge. The preferred embodiment is, lightweight enough for one person to carry, can be used in the field, and utilizes inexpensive abrasives. The method of shaping and polishing is safer than in the prior art, since the operator&#39;s hands are farther away from the cutter. The operator&#39;s hands are also available to control the various hoses, cords and valves. Since the weight of the apparatus is bearing on the stone slab, the physical nature of manual shaping and polishing has been made less strenuous. 
     While the foregoing details what is felt to be the preferred embodiment of the invention, no material limitations to the scope of the claimed invention are intended. Further, features and design alternatives that would be obvious to one of ordinary skill in the art are considered to be incorporated herein. Among such alternatives are the materials to which the preferred embodiments are applied. While stone has been listed as the primary material herein, those skilled in the art will understand that the principles of the invention illustrated herein may be applied similarly to other hard materials, including but not limited to brick, tile, glass, synthetic stones, metals, composites and even some plastics. Various types of tools, including different power sources, is within the scope off the present invention. The scope of the invention is set forth and particularly described in the claims herein below.