Abstract:
A flame-resistant buffing wheel and a method of making thereof. The buffing wheel is comprised of a buffing material which has been treated with an aqueous flame-retardant solution, and allowed to dry. The treatment may take place either before or after the buffing wheel is assembled.

Description:
FIELD OF THE INVENTION 
     This invention relates to the buffing or finishing of objects of metal and other compositions and it has particular relationship to buffing materials and a method for making them flame-resistant. 
     BACKGROUND OF THE INVENTION 
     A buffing wheel or buff typically includes a ring of metal from which extends an annulus of buffing material. Cotton fabric, polyester/cotton fabric, and sisal are commonly used as buffing material. The ring has teeth which engage the annulus of buffing material near its inner periphery and hold the buffing material in place. 
     In use, the buffing wheel is mounted on a drive shaft and is rotated. The rotating buffing wheel and the object to be buffed are in contact during the buffing process. Although buffing wheels are used singularly, common practice is to stack or gang a number of buffing wheels on a shaft for the purpose of buffing large objects like steel bumpers, aluminum extrusions and the like. Examples of buffing apparatus are disclosed in U.S. Pat. Nos. 2,805,530; 3,365,742; 3,706,167; 3,967,418; 4,799,338; 4,850,158; 4,882,880 and 5,560,744, the disclosures of which are incorporated by reference herein. 
     The buffing material (fabric and the like) from which layers in buffing wheels have been composed commonly include cotton and/or sisal. Sisal is a long coarse fiber that is twisted into strands and woven into a buffing material. Different buffing materials are used for different applications. In addition, the stiffness of the cotton buffing material may be regulated by the application of stiffening agents such as resins and ethylene vinyl acetates or polyethylene vinyl acetates either before or after the assembly of the buffing wheel. 
     In a typical buffing operation, a buffing compound such as an emulsion of hydrogenated fatty acids, water and abrasive grains is applied to the periphery of the buffing wheel. The buffing wheels are rotated at a high speed, typically 5000-9500 surface feet per minute. The object to be buffed makes contact with the buffing wheel during the process. 
     As the buffing wheels are used, the buffing material produces a dust and/or lint-like residue or swarf. Additionally, the buffing process generates metallic residue from the object being buffed. The residue from the buffing material and the metallic residue from the buffed object combine with residual buffing compound to form a highly-flammable buffing residue. Buffing residue as defined in this application includes the dust and/or lint-like buffing residue from the buffing material alone or with any combination of the metallic residue and/or the residual buffing compound. 
     Potential fires associated with this buffing residue are a serious concern. In order to avoid these fires, the buffing residue typically is removed by a conventional-type air exhaust system and is then collected in a collector, such as a bag house. The contents of the bag house must be removed often or the highly volatile contents may catch fire in the bag house through spontaneous combustion. 
     A second potential source of fire is from the buffing wheels themselves. Due to heat created by the various sources of friction (e.g., between the clinch ring and the drive shaft, the buffing material and the work piece, etc.) the buffing material is also at risk of catching fire during the buffing process. 
     SUMMARY OF THE INVENTION 
     The present invention provides a flame-resistant buffing wheel and a method of making same The buffing wheels of the present invention are comprised of a buffing material which has been treated with an flame-retardant solution. The buffing material may be treated either before or after the buffing wheels are assembled. 
     The flame-retardant solution includes a flame-retardant compound, and a penetrating agent which is applied to the buffing material. The treated buffing material is then allowed to dry. During tests of the treated buffing material over an open flame, no flame appears on the buffing material but the buffing material may smolder. The buffing residues resulting from the use of treated buffing wheels have also been found to be flame-resistant. 
     Advantages of this invention over prior systems are that in addition to rendering the buffing material flame-resistant, the buffing residues are also rendered flame-resistant. 
     The buffing wheels made in accordance with the present invention may be of any design presently known or contemplated in the future. Examples of known forms of buffing apparatus are illustrated in the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: 
     FIG. 1 is a perspective view of a buffing wheel; 
     FIG. 2 is a perspective view of a ganged or stacked buffing apparatus; 
     FIGS. 3A,  3 B and  3 C are perspective views of the system for treating the buffing material on an assembled buffing wheel. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The buffing wheel  33  shown in FIG. 1 includes a metallic clinch ring  35  typically made of steel, securing layers  37  of buffing material which extend radially from the ring in an annulus  39 . A buffing apparatus  31  formed of ganged or stacked buffing wheels  33  is shown in FIG.  2 . The buffing apparatus  31  may be formed of buffing wheels  33  alone, or it may be formed of buffing wheels  33  combined with spacers  49 . Buffing wheels may also be used individually. 
     The buffing material typically contains one or more of the following: cotton, polyester/cotton blend, and sisal, although other materials may be used. Preferably, the buffing material consists substantially of cotton fabric. To make a buffing wheel, the buffing material is cut on a bias of approximately 30° to 60°. It is cut to desired widths (typically 4 to 18 inches, depending on desired dimension), and rolled into lengths of up to 1,000 yards. The rolled, biased, cut buffing material is then wound on a split drum of an iris machine drum. The iris closes, tucking the buffing material into a metal clinch ring which is mounted in between the split drum. The drum may be any diameter, typically 6 to 36 inches. The buff section is then removed from the iris machine. 
     The buffing material of the present invention is treated with a flame-retardant solution comprised of a flame-retardant compound, a penetrating agent and water. The flame-retardant compound is preferably an aqueous halogenated compound of the type manufactured by Apollo Chemical Corporation under the name of BARFIRE PCR. The penetrating agent is preferably a surfactant and most preferably Silwet L-77 surfactant having the chemical name Polyalkyleneoxide Modified Heptamethyltrisiloxane manufactured by CK Witco Corporation. An effective amount of the flame-retardant compound is used to minimize the flammability of the buffing residues and buffing material. The effective amount of flame-retardant compound present in the solution is at least about 15% and in the range of about 15-40% (preferably about 35%) by weight of solution. The effective amount of flame-retardant compound in the flame-retardant solution typically varies with the weave of the buffing material. More flame-retardant compound typically is needed when the weave of the buffing material is closed (or tighter). Open weave buffing material requires less flame-retardant compound. 
     The effective amount of penetrating agent is at least about 0.025% and in the range of 0.025-0.6% (preferably 0.04%) by weight of solution. The penetrating agent functions to help “wet” the buffing material, enhancing penetration into the buffing material by the solution. Like the amount of flame-retardant compound, the effective amount of penetrating agent typically varies with the weave of the buffing material. More penetrating agent is needed when the weave of the buffing material is closed. Open weave buffing material requires less penetrating agent. The solution also comprises water, and may also include known stiffening agents and/or dyes typically used for buffing materials. 
     In order to treat the buffing material of an assembled buffing wheel  33 , the components of the flame-retardant solution are mixed in a larger container or drum  45 . In one embodiment, the buffing wheels  33  are arranged horizontally on a vertical pole  49  separated by typically 0.75 to 1.25 inch spacers  43  (FIG.  3 A). The pole  49  is lowered vertically into the container  45  so that the buffing wheels  33  are immersed in the solution  47  (FIG.  3 B). After a period of time, preferably one to five minutes, depending on the buffing material, the pole  49  is removed from the solution (FIG. 3C) and the buffing wheels  33  are allowed to dry. During the drying process, the pole is allowed to drip for 7 to 11 minutes. Afterwards the buffing wheels are spun for 3 to 6 minutes at at least about 200 revolutions per minute on the pole. The buffing wheels  33  may be spun dry on the pole itself or may be preferably loaded onto a rotary shaft on which they are spun. Also, the buffing wheels may be dried in a heat room at 90 to 120° F., or an oven with a temperature range of 150 to 190° F. 
     In another embodiment, the buffing material may be treated by vertically dipping a portion of the buffing material into the fire-retardant solution and then rotating the buffing wheel so that substantially all of the buffing material is sufficiently treated. The buffing wheels are then dried as described. 
     Buffing material treated before buffing wheel assembly may be treated in this manner: the flame-retardant solution is applied to buffing material at the time of the standard process of cloth dying, starching or finishing. The solution may be preferably incorporated into existing treatments, or be applied separately. Typically, buffing material is run in a single ply through a “bath” of treatment, then through a drying process for heating and/or curing the buffing material, and finally rolled into high yardage rolls. Assembly of the buffing wheels then takes place in a conventional manner. 
     If not otherwise stated herein, it may be assumed that all components and/or processes described heretofore may, if appropriate, be considered to be interchangeable with similar components and/or processes, unless an indication is made to the contrary. 
     It should be appreciated that the apparatus and methods of the present invention may be configured and conducted as appropriate for the application. The embodiments described above are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is defined by the following claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.