Abstract:
Apparatus and methods for forming a generally spherical object from a workpiece are disclosed. In one embodiment, an apparatus includes a frame having a laterally-projecting elongated member, and a support member slideably engaged with the elongated member. A motor is coupled to the support member and pivotably suspended below the elongated member. A surface treating member is attached to the shaft of the motor and is adapted to engage the workpiece. In an alternate embodiment, an apparatus includes two laterally-projecting elongated members and a pair of surface treating modules that engage the workpiece from opposite sides. In yet another embodiment, an apparatus includes three laterally-projecting elongated members and three surface treating modules that engage the workpiece from approximately equidistant directions. The inventive apparatus and methods advantageously allows gravity to naturally force the surface treating members toward the workpiece, thereby improving the engagement of the surface treating members toward the workpiece.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention generally relates to the field of lapidary, and to apparatus and methods of abrading and polishing rough materials into a generally spherical shape. More specifically, such abrasion and polishing is affected by rotation of surface treating members, such as grinding cups and the like, which receive and support said rough material.  
           [0003]    2. Related Art  
           [0004]    U.S. Patent Documents  
           [0005]    U.S. Pat. No. 2,405,344 August, 1946 Cloutier 51/56  
           [0006]    U.S. Pat. No. 3,024,578 March, 1962 Mushkin 51/117  
           [0007]    U.S. Pat. No. 3,110,987 November, 1963 Arneson 451/268  
           [0008]    U.S. Pat. No. 3,167,884 February, 1965 Thompson 51/3  
           [0009]    U.S. Pat. No. 3,609,918 October, 1971 Hillman 451/268  
           [0010]    U.S. Pat. No. 3,961,448 June, 1976 Akahane 51/117  
           [0011]    U.S. Pat. No. 3,971,164 July, 1976 Albin et al. 51/129  
           [0012]    U.S. Pat. No. 5,299,394 April, 1994 Surdacki 51/289  
           [0013]    U.S. Pat. No. 5,484,329 January, 1996 Engelbrekston 451/523  
           [0014]    U.S. Pat. No. 5,613,896 March, 1997 Haus et al. 451/50  
           [0015]    U.S. Pat. No. 6,186,875 February, 2001 Cook et al. 451/268; 451/50  
           [0016]    Foreign Patent Documents  
           [0017]    3121759 May, 1991 JP 451/50  
           [0018]    4269157 September, 1992 JP 451/50  
           [0019]    1122484 November, 1984 SU 451/50  
           [0020]    In general, prior art lapidary machines may be characterized as having three essential elements: (1) a plurality of concave sanding blocks or abrading cups; (2) a motor or motors to rotate the sanding blocks or abrading cups; and (3) support structure for the preceding elements. Additional or less typical components include mechanical adjustments, electrical controls, slurry systems, and pneumatic cleaning devices. Of these, four examples (U.S. Pat. Nos. 3,024,578, 3,110,987, 3,167,884 and 3,961,448) are related more specifically toward lapidary sphere grinding. The remainder are generally related more closely with the resurfacing of bowling balls.  
           [0021]    Regarding the first element, some form of concave sanding blocks, grinding cups, or standard pipe reducer fittings is usual, but not universal, to the field of sphere abrading devices.  
           [0022]    Regarding motors for rotating the concave abrasion blocks, various configurations are disclosed in the related art, and are particular to the scale and requirements of said art.  
           [0023]    Cloutier (U.S. Pat. No. 2,405,344) discloses a single motor connected by a belt to an elliptical gear which imparts “reciprocation and rotation” to the bottom one of the six “bowl-shaped members”. Similarly, Mushkin (U.S. Pat. No. 3,024,578) and Thompson (U.S. Pat. No. 3,167,884) each drive only one shaft and concave abrasion block, imparting all motion to the object through that single propulsion.  
           [0024]    Regarding support structures of related art, each of the inventions referenced here is configured to accommodate its particular method and components. In all cases however, the machines are designed such that the support structure for the motors and grinding cups are attached directly to a base, table, or framework that extends the motors and grinding cups in an upward fashion, generally using a hinge, where the force of gravity would naturally tend to try to pull the grinding cups away from the center of the material being worked on, and therefore typically employ additional devices to hold the motor mounts perpendicular, and to apply grinding pressure against the rough sphere material. Additionally, in all cases, machines are designed as a single device without independent components capable of being reconfigured.  
         SUMMARY OF INVENTION  
         [0025]    The present invention is directed to apparatus and methods of grinding, shaping, and polishing a workpiece, including rock, gemstone, minerals, crystals and other materials, into a generally spherical shape. The inventive apparatus and methods disclosed herein have application to a variety of fields, including lapidary work, and the general manufacture of spherical objects, such as bowling balls and the like.  
           [0026]    In one aspect, an apparatus in accordance with the invention includes a frame having a laterally-projecting elongated member, and a support member slideably engaged with the elongated member. A motor is coupled to the support member and pivotably suspended below the elongated member. A surface treating member is attached to the shaft of the motor and is adapted to engage the workpiece. The inventive apparatus advantageously allows gravity to naturally force the surface treating member toward the workpiece, thereby improving the engagement of the surface treating member toward the workpiece.  
           [0027]    In alternate aspects, embodiments of apparatus in accordance with the invention may include multiple grinding-head modules, a configuration (or mounting) hub, and a grit dispenser. In one alternate aspect, an apparatus includes two laterally-projecting elongated members and a pair of surface treating modules that engage the workpiece from opposite sides. In yet another aspect, an apparatus includes three laterally-projecting elongated members and three surface treating modules that engage the workpiece from approximately equidistant directions. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0028]    [0028]FIG. 1 is a perspective view of a grinder-head module in accordance with an embodiment of the invention.  
         [0029]    [0029]FIG. 2 is a perspective view of two grinder-head modules combined by a rectangular hub into a two-headed machine in accordance with another embodiment of the invention.  
         [0030]    [0030]FIG. 3 is a perspective view of three grinder-head modules combined by a triangular hub into a three-headed machine in accordance with yet another embodiment of the invention.  
         [0031]    [0031]FIG. 4 is an exploded view of the grinder-head module and component pieces of FIG. 1.  
         [0032]    [0032]FIG. 5 is a detail view of the grinder-head module of FIG. 1 with inset details of an embodiment of a motor slide mount, and an embodiment of a shock-absorbing tension adjustment.  
         [0033]    [0033]FIG. 6 is a detail and exploded view of an embodiment of a Grit-Feeding System. 
     
    
     DETAILED DESCRIPTION  
       [0034]    Description of the Preferred Embodiments  
         [0035]    The present invention is generally directed to apparatus and methods of grinding, shaping, and polishing a workpiece, including rock, gemstone, minerals, crystals and other materials, into a generally spherical shape. Many specific details of certain embodiments of the invention are set forth in the following description and in FIGS.  1 - 6  to provide a thorough understanding of such embodiments. One skilled in the art will understand, however, that the present invention may have additional embodiments, or that the present invention may be practiced without several of the details described in the following description.  
         [0036]    Referring to FIGS. 1 and 4, there is presented an embodiment of a grinder head module  100 . The grinder head module  100  comprises a framework  1  and  2 , which are fastened together and support a machine slide  3 , which rests on top of, and is fastened to the framework  1  and  2 .  
         [0037]    In the embodiment shown in FIG. 1, a motor slide  6  rests on top of the machine slide  3 , and a main leadscrew  4  passes through a main leadnut  50  fixed to the motor slide  6 , and is rotatably supported at either end by the framework  1  and  2  with suitable collar-nuts, bearings, or other suitable devices. A handwheel  5  is attached to the main leadscrew  4  and for controlling the rotation of the main leadscrew  4 .  
         [0038]    As further shown in FIGS. 1 and 4, a horizontal adjustment slide  7  rests on top of the motor slide  6 , and the vertical metal tabs on the horizontal adjustment slide  7  extend below, and on either side of the outside edges of the machine slide  3 . A secondary leadscrew  8  passes through a secondary leadnut  52  at the rear of the motor slide  6  and is secured with a shaft collar or other suitable support at either end of the horizontal adjustment slide  7 . An adjustment knob  9  is attached to the secondary leadscrew  8 , and controls the rotation of the secondary leadscrew  8 , which in turn imparts horizontal motion to the rear portion of the motor slide  6  by exerting force against the edge of the machine slide  3  by the vertical metal tabs on the horizontal adjustment slide  7 .  
         [0039]    A motor mount  11  is attached to the motor slide  6  by means of a pivot pin  10 , which passes through a forward mounting bracket of the motor slide  6 , and a top hinge hole in the motor mount  11 , thus suspending the motor mount  11  entirely from the forward mounting bracket of the motor slide  6 . In this way, the motor mount  11  and the motor slide  6  are slideably coupled to the machine slide  3 . During operation, rotation of the handwheel  5  causes rotation of the main leadscrew  4  which in turn causes forward and backward motion of the motor slide  6  and the motor mount  11  along the machine slide  3 . Similarly, rotation of the adjustment knob  9  causes rotation of the secondary leadscrew  8  for controlling the angle of the motor slide  6  and the motor mount  11 .  
         [0040]    As shown in FIG. 4, the embodiment of the machine  100  further includes shock-absorbing tension adjustment device  58  that includes a Delrin block  12  attached to a vertical leadscrew  15 . The vertical leadscrew  15  passes through a shock-absorber cylinder  54  at the rear of the motor mount  11 , and is threaded through a collar nut  13 . Now referring to FIG. 5, in the assembled position, the collar nut  13  rests against a flange inside the shock-absorber cylinder  54  at the rear of the motor mount  11 . The vertical leadscrew  15  the passes through a compression spring  14 , and a shock-absorber cap  16 . The compression spring  14  rests against the collar nut  13 , inside the shock-absorber cylinder  54 , and is held in place and under compression by the shock-absorber cap  16 . An auxiliary handwheel  17  is attached to the vertical leadscrew  15 , and controls rotation of the vertical leadscrew  15 . The rotation of the vertical leadscrew  15  in turn increases or decreases the vertical attack angle of the motor mount  11  by placing pressure on the underside of the motor slide  3 , thereby increasing the angle between the motor slide  3  and the shock-absorber cylinder  54 , and raising or lowering the vertical attack angle of a grinding cup  21  relative to the sphere material, as described more fully below.  
         [0041]    The shock-absorbing tension adjustment device  50  advantageously permits adjustment of the vertical attack-angle of the grinding cup  21  for each grinder head module  100 . The shock-absorbing tension adjustment device  50  may additionally act as a locking mechanism to secure the sliding motor mount  6  in place on the machine slide  3  during grinding operation.  
         [0042]    In the machine embodiment  100  shown in FIGS. 1 and 4, a gearmotor  18  is attached to the motor mount  11 , and a grinding Cup  21  is attached to the gearmotor  18  by means of a threaded motor shaft  22 , which passes through a hole in the motor mount  11 . A variety of grinding cups  21  may be used, including a diamond sintered cup for coarse grinding, or a standard plumbing pipe reducer used during a grinding process with abrasive grit and water in a slurry, according to the operator&#39;s needs and preferences.  
         [0043]    [0043]FIG. 2 is a perspective view of a two-headed machine  200  in accordance with an embodiment of the invention. As shown in FIG. 2, a pair of grinder head modules  100  of the type described above are attached to a configuration (or mounting) hub  20 . In this embodiment, the configuration hub  20  is a rectangular hub  20 , however, any suitable hub configuration may be employed. When attached to the mounting hub  20 , the grinding-head modules  100  and hub  20  become an integral framework for the assembled machine  200 , leaving an open central area  70  beneath the machine, accommodating the operators choice of method to catch and dispose of waste materials, including abraded materials from the workpiece  60 , slurry and excess abrasive grit. Water is dripped onto the workpiece by means of water dripping system  500 .  
         [0044]    [0044]FIG. 3 is a perspective view of a three-headed machine  300  in accordance with yet another embodiment of the invention. As shown in FIG. 3, the three-headed machine  300  includes three grinder head modules  100  (described above with reference to FIGS. 1 and 4) attached to a configuration hub  19  which, in this embodiment, is a triangular hub. As set forth above, alternate embodiments of the hub  19  may be employed. Again, an open central area  70  is located beneath the machine  300  to accommodate the operators choice of method to catch and dispose of waste materials. Water is dripped onto the workpiece by means of water dripping system  500 . Water dripping systems of the type shown in FIGS. 2 and 3 are known in the art and are commercially available as “Snap-lock”, or “Snap-flow” coolant tubing with flow-control valve. Such coolant tubing is commonly used in both lapidary and machine-tool operations to dispense water, or oil onto a workpiece according to need. Water is stored in a suitable plastic container that is removably suspended from Hubs  19  or  20  by means of a hanger bracket.  
         [0045]    The machine embodiments  200 ,  300  shown in FIGS. 2 and 3 may further include an abrasive (or grit) delivery system. FIG. 6 shows an embodiment of a grit-feeding system  400  suitable for use with the machine embodiments  200 ,  300 . As shown in FIG. 6, the grit-feeding system  400  includes a frame  23  which may be attached to the configuration hub  19 ,  20  of the machine, thus suspending the grit-feeding system  400  above the work area. A feed motor  28  is bolted to the frame  23  and a shaft from the feed motor  28  extends through a center hole of the frame  23 , with a fixed shaft-coupling device.  
         [0046]    A grit-dispenser module  29  is coupled to the frame  23  and includes a grit bottle  27 , a grit-dispenser head  24 , a grit auger  25 , and a grit cap  26 . The grit-dispenser module  29  may be changed according to operator preference by pulling the grit-dispenser module  29  from the frame  23 , thereby disconnecting the grit auger  25  from the feed motor  28 , and the entire unit may be replaced with another module containing a different grit particle. The top of the bottle  27  is inserted through the retaining ring at the top of the frame  23 , and the grit-dispenser head  24  is snapped into place, thus securing the grit auger  25  to the motor shaft of the feed motor  28 . In comparison with the prior art grit dispenser, the grit-dispenser module  29  simplifies the grit-changing process and eliminates the need to clean a multi-use grit tube.  
         [0047]    Generally, the operation of the two-headed machine  200  and the three-headed machine  300  are similar, and will be described below with reference to the singular “machine  200 ,  300 .” First, the machine  200 ,  300  is operated by closing the grinding cups  21  upon a workpiece  60  (shown in FIGS. 2 and 3), typically a rough sphere of material, by turning the main handwheel  5  and auxiliary handwheel  17  for each grinder head module  100 . The machine slides  3  are arranged to position the grinding cups  21  at angles of 120 degrees, or 180 degrees respective to the workpiece  60  when configured as a three-headed machine  300 , or a two-headed machine  200 , respectively.  
         [0048]    After positioning the workpiece  60  within the grinding cups  21 , the handwheels  5 ,  17  are turned to secure each motor slide  6  into position, and the grinding operation may begin by activating the motors  18 . The amount of abrasive grit being dispensed by the turning grit auger  25 , and manual adjustment of the location of the grit dispensing hole on the grit cap  26 , are determined by rotating the grit cap  26  until the desired rate of abrasive grit flow is achieved. As the independently-driven grinding cups  21  turn, the motion of each grinding cup  21  is frictionally imparted to the workpiece  60 . The workpiece  60  is randomly oscillated through all three rotational axes during the grinding process, which abrades and removes excess asymmetrical “high” areas of the workpiece until such areas are removed and the material becomes generally spherical. If desired, this operation may be repeated with progressively finer grit particles and grinding cup selections until a spherical object with a gem-like surface luster is achieved.  
         [0049]    One may note that the machines  200 ,  300  employ motor mounts  11  which suspend the motors  18  and grinding cups  21  beneath the machine slide  3 , rather than resting above it on the frame  2  or a table or other base. This aspect of the invention allows gravity to work in favor of the operation, holding the workpiece  60  more precisely in the center of the rotating cups  21 , and reducing stress on the overall structure. The machine slides  3  and leadscrews  4 ,  8 ,  15  provide precise adjustment in all three axes for precise fine-tuning of grinding and polishing operations by turning knobs  9 , or handwheels  5 ,  17 . In addition, the framework  1 ,  2  accommodates conversion from tabletop to a floor model by attachment of leg extensions (not shown).  
         [0050]    The machines  200 ,  300  may be used for a variety of different surfacing/polishing applications, including but not limited to lapidary work. For example, bowling balls, large granite and marble spheres, and other materials and workpieces may be accommodated by adjustment of the motor mounts and/or by use of variously-sized cutting heads/abrasion blocks and motor shafts lengths. Larger, heavier objects may be accommodated by simply scaling up the size of the apparatus, and by the addition of heavy duty gear motors of varying torque and rpm as required.  
         [0051]    The machines  200 ,  300  in accordance with the invention exhibit several advantages over the prior art. For example, the machines  200 ,  300  advantageously permit the position of the grinding cups to be precisely adjusted in three axes. Each motor mount  100  includes a shock-absorbing tension adjustment device  58  that permits adjustment of the vertical attack-angle of the grinding cup  21 , as well as a horizontal adjustment screw  7  that allows minute adjustments in horizontal attack-angle relative to the workpiece  60 . Thus, the position of the grinding cups  21  may be precisely adjusted in three axes by means of the main and auxiliary handwheels  5 ,  17  and the adjustment knob  9  on each grinding-head module  100 .  
         [0052]    Another advantage of the inventive apparatus and methods disclosed herein is that each motor  18  and grinding cup  21  are suspended below the machine slide  3  on a pivoting pin  10  that allows gravity to naturally pull the grinding cups  21  toward the workpiece  60 . This aspect of the invention employs the force of gravity to maintain and improve the frictional engagement of the grinding cups  21  with the workpiece  60 .  
         [0053]    Yet another advantage of the inventive apparatus and methods disclosed herein is that most of the moving machine parts are located above the workpiece  60 , allowing waste debris, grit, and slurry to fall away from, rather than into, the machine parts. As a result, generally spherical objects may be formed faster because the improved design allows a more automated process that requires less cleaning and maintenance. Operation efficiency is further improved because slurry-catching systems may be easily exchanged, or cleaned while the machine is in operation resulting in less down-time during grinding, and grit-changing operations are much simplified by eliminating the need to clean a multi-use grit tube.  
         [0054]    Additional advantages of the inventive apparatus and methods disclosed herein over related art include: (1) a modular design of the machine, unique in the industry, allows flexibility of configuration according to need. (2) a much improved design and configuration of the motor mount brackets (and, therefore, the motors and abrasion blocks or grinding cups) and means for their adjustment; (3) “shock-absorber” tension adjustment, allows precise adjustments of grinding cup vertical attack angle that additionally acts as a brake on the machine slide to secure the motor mount in position during operation, and may also absorb bumps and shocks caused in initial grinding operations due to less-than-perfectly spherical rough material; and (4) modular grit-feed system allows for a quick change of abrasive grit with no need for cleanup as with a single fixed grit-feed tube which must be disassembled and cleaned thoroughly in order to change to a finer grit particle.  
         [0055]    The detailed descriptions of the above embodiments are not exhaustive descriptions of all embodiments contemplated by the inventor to be within the scope of the invention. Indeed, persons skilled in the art will recognize that certain elements of the above-described embodiments may variously be combined or eliminated to create further embodiments, and such further embodiments fall within the scope and teachings of the invention. It will also be apparent to those of ordinary skill in the art that the above-described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the invention.  
         [0056]    Thus, although specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. The teachings provided herein can be applied to other apparatus and methods of grinding, shaping, and polishing a workpiece into a generally spherical shape, and not just to the embodiments described above and shown in the accompanying figures. Accordingly, the scope of the invention should be determined from the following claims.