Patent Publication Number: US-6217424-B1

Title: Metal-polishing technique

Description:
BACKGROUND OF THE INVENTION 
     The invention relates in general to the field of polishing techniques and, more particularly, to the polishing of metal materials. Specifically, the invention relates to a technique for polishing aluminum, stainless steel, and brass. 
     Increased metal use and rising costs of metals have caused focus to be placed on the refurbishing of metals through polishing. Generally, conventional metal-polishing techniques do not allow for the capability to effectively polish a detailed and ornate metal object in a consistent fashion because of hard-to-reach comers and insets. Thus, it would be beneficial to have a metal-polishing technique that is capable of overcoming the shortcomings of conventional methods. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a technique for polishing metal objects such as, for example, those made of aluminum, stainless steel, and brass. The technique employs a metal-polishing apparatus which includes a double-jointed arm assembly and a table assembly. The arm assembly includes a brush assembly, a handle, and an actuating device. The double-jointed nature of the arm assembly advantageously allows an operator to effectively polish a detailed and ornate metal object. The table assembly has a frame, a rotatable table-top assembly, and a mechanism for securing the metal object. The metal object to be polished is placed on the tabletop assembly and allowed to rotate with respect to the frame. The present invention also relates to the preparation, polishing, and post-polishing methods employed with the metal-polishing apparatus. The present invention enables aluminum, brass, and stainless steel objects to be effectively polished, and therefore refurbished, by removing a significant amount of damage (i.e., scratches) from the metal object. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: 
     FIG. 1A illustrates one embodiment of the polishing apparatus of the invention; 
     FIG. 1B illustrates the embodiment of FIG. 1A with a metal wheel rim on the apparatus of FIG. 1A; 
     FIG. 2 is an enlarged view of the arm assembly of FIG. 1A; 
     FIG. 3 is an enlarged view of the table assembly of FIG. 1A; 
     FIG. 4 is a hydraulic schematic that can be used with a polishing apparatus in accordance with the invention. 
     FIGS. 5A and 5B are enlarged views of the table-top assembly of FIG. 3; and 
     FIGS. 6-7 illustrate clamping mechanisms in accordance with the invention. 
     FIG. 8 is a flow chart for the polishing technique of the invention. 
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Illustrative embodiments of the invention are described below as they might be employed in a technique for polishing metals. In the interest of conciseness, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any actual embodiment, numerous implementation-specific decisions must be made to achieve the developer&#39;s specific goals, such as compliance with system-related and business-related constraints. Moreover, it will be appreciated that even if such a development effort might be complex and time-consuming, it would nevertheless be a routine undertaking for those of ordinary skill having the benefit of this disclosure. 
     Overview 
     Metal objects (such as those made from brass, aluminum, and stainless steel) can be damaged through routine use. For example, an aluminum wheel can become damaged over time by scratches from curbs and rocks and asphalt deposits. The present invention is a polishing technique that enables a significant amount of scratches to be removed from a metal object. FIG. 1A illustrates a polishing apparatus  100  in accordance with the invention that includes a double-jointed arm assembly  105  and a table assembly  110 . The double-jointed arm assembly  105  allows manipulation of the arm assembly by an operator (not shown) in multiple directions. The operator can control the angle of a polishing brush attached to the arm assembly to virtually ensure that even small crevices (that would not have been polished with conventional techniques) are effectively polished. 
     The metal object is prepared for polishing by removing the outer protective coating and sanding the metal object until it is consistent (i.e., uniformly sanded with the sanding lines in one direction). After the metal object has been prepared for polishing, it is automatically centered and secured on table-top assembly  115  which, in turn, is connected to table assembly  110 . Table-top assembly  115  rotates the metal object. A brush attached to arm assembly  105  polishes the metal object while it is rotating. FIG. 1B illustrates the use of polishing apparatus  100  to polish an aluminum wheel rim. When the metal object has been polished, the polishing compound is removed by cleaning the metal object. 
     Specific Embodiments 
     FIG. 2 illustrates the double-jointed arm assembly  105  that can be used in a metal-polishing apparatus in accordance with this invention. The arm assembly includes a first rod  200 . Rod  200  can be constructed such that it contains two separate pieces: a lower piece  205  which can be fused to a frame assembly (not shown) and an upper piece  210  coupled to rod  205 . The use of two pieces for rod  200  enables the arm assembly to be separated from the frame assembly. Rod  200  is typically constructed from a material, such as stainless steel, that provides the rigidity needed to minimize bending. 
     Rod  215  is rotatably coupled to rod  200  and rod  225  (see FIG.  1 B), thereby forming two joints. Rods,  200 ,  215 , and  225  form a double-jointed arm. Joint  226  allows rotation of the arm assembly  105  about a horizontal axis. Joint  227  allows rotation of the arm assembly  105  about a vertical axis. The double-jointed nature of the arm assembly enables the operator to effectively polish the metal object (not shown). The two joints allow horizontal, axial, vertical, and torsional movement such that the operator can polish portions of the metal object that may not have been able to be reached with conventional polishing techniques. 
     At the end of rod  215  labeled  220 , springs (not shown) can be attached to offset the weight of the third rod. Free weights can also be attached to end  220  of rod  215  to further offset the weight. Rods  215  and  225  can be formed from the same material as rod  200 . An actuating device  230  is attached to the top end of rod  225  while a brush assembly  235  is attached to the lower end of the rod. Actuating device  230  is also coupled to brush assembly  235  by a connecting device (not shown). The actuating device may be any type of conventional actuating device (e.g., a pneumatic or hydraulic motor). 
     Brush assembly  235  is typically snapped into a lock position on rod  225 . A passage  243  (which is connected to rod  200 ) provides the power for actuating device  230 . Brush assembly  235  rotates when the actuating device  230  is powered. A handle  245  may be attached to rod  225 . Vertical movement of handle  245  causes rod  215  to rotate in relation to rod  210 . Similarly, angular movement of handle  245  causes rod  225  and brush assembly  235  to rotate in relation to rod  215 . Thus, through the use of handle  245 , the operator can control the manner in which brush assembly  235  engages the metal to be polished (not shown). 
     One skilled in the art will realize that the arm assembly of FIG. 2 can be implemented with conventional polishing tables. However, it is also adaptable to a table assembly in accordance with the present invention. FIG. 3 shows a table assembly  110  which includes a table-top assembly  115  and a frame assembly  300 . Actuating device  305  within frame assembly  300  is connected to a support member  310  of table-top assembly  115 . The actuating device  230  may be any type of conventional actuating device (e.g., a pneumatic or a hydraulic motor). Frame assembly  300  also includes a fluid reservoir  315  coupled to actuating device  305 . In embodiments wherein a hydraulic motor is used for the actuating device, the reservoir is a hydraulic fluid tank. 
     FIGS. 5A and 5B illustrate a top view of table-top assembly  115 . Three clamping mechanisms  500  are connected to table-top assembly  115  within orifices  505 . FIGS. 6 and 7 illustrate a possible configuration for clamping mechanism  500  in which two cutterpins  600  are used to secure the device. The clamping mechanisms are designed to slide within the orifices to secure the metal object to be polished. For example, if a metal wheel rim mounted to a wheel is being polished, the clamps can be designed to slide to the innermost point of the orifice to allow the rim to be placed on the table. After the rim and wheel are placed on the table, the clamps can be controlled to slide outward evenly until they engage the rim allowing automatic centering and securing of the wheel rim. If a different type of metal object (e.g., a portion of a motorcycle) is to be polished, the clamps can slide inward to secure the object around its outside edge. 
     FIG. 5A shows a circular plate of the table-top assembly  110 . Orifices  505  are shown with clamping mechanisms  500  extended inward. Linking arms  510  are connected to each of the clamping mechanisms so that movement of the linking arms cause each clamping mechanism to be moved from one end of orifice  505  to the other end. The linking arms  510  are also connected to the ends of pivoting device  515  such that movement of the pivoting device causes the linking arms to move. On one side of pivoting device  515 , a rod  520  is connected between the pivoting device and an engaging mechanism  525 . When engaging mechanism  525  contacts rod  520 , pivoting device  515  moves, which causes linking arms  510  to engage the clamping mechanisms  500  as shown in FIG.  5 B. 
     The engaging mechanism  525  may be a conventional engaging mechanism (e.g., a pneumatic or a hydraulic cylinder). The engaging mechanism  525  is also coupled to reservoir  315  which controls when the engaging mechanism  525  contacts rod  520 . One of ordinary skill will realize that the spinning of the table-top assembly could be controlled separately from the clamping mechanisms presently described. In addition, the rotation of the brush assembly could also be separately controlled from the rotation of either the pivoting device or the table-top assembly. Despite the independence between the two actuating devices and the engaging mechanism, they may all use reservoir  315 . The table-top assembly described can be adapted to fit with a conventional arm assembly or the arm assembly of the present invention. 
     FIG. 4 is a hydraulic schematic diagram that can be used with a polishing apparatus, in accordance with the invention. Reservoir  315  is connected to a main hydraulic passage  400  through a valve  405 . Electric motor  410  is connected to pump  415  which provides the force needed to fill hydraulic passage  400 . Relief valve  417  can be used to relieve pressure in hydraulic passage  400  to minimize excessive pressure. Valves  420  are used to couple motor  425 , motor  430 , and cylinder  435  to hydraulic passage  400 . Motor  425  can be a torque motor with approximately 150 rpm and can be used to control the rotation of the table-top assembly  115 . Motor  430  could be used to control the rotation of the brush attachment  235  and could be a gear motor with approximately 2000 rpms. A pressure-reducing valve  423  can be used to reduce the pressure in the portion connected to the hydraulic cylinder  435  to minimize the likelihood of damaging the cylinder. Hydraulic cylinder  435  may be used to engage/disengage the clamping mechanism  400  (see below) on the table-top assembly  115 . One skilled in the art will appreciate that variations can be made to the schematic without departing from the inventive concept described herein. 
     The arm assembly and the table assembly in accordance with the invention cooperatively fit together to generate a polishing apparatus that can be used in a metal-polishing technique in accordance with the invention. FIG. 8 is a flow diagram that illustrates this metal-polishing technique. Block  800  is the application of an acid to the metal to be polished. The acid can be used to remove a protective outer coating on the metal, which is typically referred to as stripping the metal. Conventional acids (e.g., TAL Strip II) may be used as a stripper. At block  805 , a conventional method may be used to remove the stripper (e.g., pressure hosing). One skilled in the art will understand that the method used to remove the acid depends upon the type of stripper used. 
     After the metal object has been stripped, it is sanded at block  810  in preparation for polishing the metal. Conventional sanding techniques and tools (e.g., a die grinder and a roll-lock disk) may be used. The number of sandings and coarseness of the sanding tool depend upon the condition of the metal object. For example, a metal object with many deep scratches may need to be sanded several times with sanding objects of varying coarseness. The metal object is sanded until it has a consistent finish (i.e., all of the sanding lines are in the same direction and are uniform). If the finish is not consistent, the sanding step is repeated. Typically, sanding discs may include the following commercial products: coarse: #05528; medium: 05527 and fine: 05523, all manufactured by the 3M Company. 
     After the metal has a consistent finish, it is placed on polishing apparatus  100 . If any portion of the metal has not been sanded, the remaining portion may be sanded while it is on the polishing apparatus. For example, if a metal wheel rim is to be polished, the “lip” of the wheel rim may be sanded once the wheel rim is placed on the polishing apparatus. The number of polishes and the type of brush depend on the condition of the wheel. 
     A conventional polishing compound may be applied to the metal with the brush attachment. Preferred polishing compounds include model nos. W-100-WD100 by California Buff (“white compound”) and CBC-36 by California Buff (“black compound”). If a second polishing compound is desired for a different type of polishing, a different brush may be attached to the brush assembly and the second compound applied to the new brush. For example, the white compound may be applied first, followed by application of the black compound. Preferred polishing brushes include the Sisal Buff brush by California Buff and a Spiral &amp; Concentric Sewed brush, also by California Buff. 
     After the metal has been polished, the polishing compound is removed with a delicate cleaning compound to prevent scratching (block  820 ). Lime rock, in the form of a light powder, is applied to the metal to remove any remaining polishing compound. If the lime rock is applied with the hands, the likelihood of the metal object being scratched during cleaning is reduced. When the metal has been cleaned, the process may be repeated with a different metal object 
     It will be appreciated by those of ordinary skill in the art having the benefit of this disclosure that numerous variations from the foregoing illustration will be possible without departing from the inventive concept described therein. Accordingly, it is the claims set forth below, and not merely the foregoing illustration, which are intended to define the exclusive rights of the invention.