US 3163968 A
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United States Patent 3,163,968 GRAPHHE COATEE) ABRASEVE BELTS Roscoe E. Nafus, 1136 N. 2nd St., Kelso, Wash. No Drawing. Filed Dec. 31, 1%2, Ser. No. 248,264- 4 Cim'rns. (Ci. 51-394) This invention relates to an abrasive sander belt having a graphite coating on the surface opposite the abrasive material.
In commercial belt sander operations using a continuous high speed traveling abrasive belt with a backing platen having a low friction material cover, a considerable amount of static electricity develops which causes dust particles to settle on the sanded article or to float in the air and prevents efiicient removal by the blower system. This is particularly true wherein large panels of 8 feet or more in length are being sanded and the blower system is located at the outlet end of the traveling belt. When such panels are sanded at the end away from the blower system the dust accumulation on the rest of the panel and in the air becomes particularly acute.
Not only does the dust create a hazard for the Workman in the area but the fine particles remaining on the panel surface work into balls on subsequent handling and stacking, often causing serious surface blemishes, requiring a down-grading of the costly finished panels and a subsequent lower market price.
Attempts to improve on the efiiciency of the dust removal have generally been in the direction of a more efiicient low friction material on the backing platens and/ or grounding the backing platens or other par-ts of the sander equipment. None of these methods has proved satisfactory in removing the dust particles. An object of the present invention, therefore, is to provide for the complete removal of the dust particles from the sanded surface.
Another object of the invention is to provide a means for the elimination of static electricity from the sander belt.
Still another object of the invention is to create a static-free environment for the sander dust particles to facilitate removal thereof.
These and other objects are accomplished generally by applying a coating of graphite to the sander belt on the surface opposite to that containing the abrasive material. A lubricating, low friction, adherent binder material is first applied to the surface of the belt to be coated with the graphite. Powdered graphite is then applied to the coating of said binder material. Alternatively, the graphite may be mixed with the lubricating, low friction, adherent binder material prior to application to the belt and the resultant mix may then be applied to the surface of the belt opposite the abrasive containing surface.
For ease and clarity in detailing the manner in which the present invention accomplishes these and other object and Without limiting ourselves except as stated hereinafter in the claims, the examples and description that follow are given as illustrative of the prepartion of a typical abrasive sander belt having the desired characteristics.
Example I The side opposite the abrasive material on a sander belt measuring 6" by 240? was rubbed with a paraffin wax block until a total of 4 gms. of wax was applied to the belt. Next, gms. of powdered amorphous graphite was evenly applied to the wax coating and another 2 gms. of paraffin wax was evenly rubbed over the surface.
The coated belt was placed on a standard sanding apparatus and used in sanding 4 foot by 8 foot plywood panels. It effectively eliminated any static electricity causing substantially all of the dust particles to travel along with the moving belt and to be removed by the 2 exhaust system located at one end of the moving sander belt.
Example 11 To 85.5 gms. of a liquid comprising 60% by Weight high boiling (300 C.) aliphatic hydrocarbons and 40% by weight fluid silicone of the methyl siloxane type was added 90.5 gms. of powdered amorphous graphite and the mixture was stirred to a smooth consistency. A total of 25 gms. of the mixture was evenly applied to the side of a 6 inch by 240 inches sander belt opposite the abrasive containing side. This belt was immediately used in a sanding operation on 4 foot by 8 foot plywood panels and proved effective in eliminating the heretofore associated static electricity permitting the sanded dust particles to travel along with the traveling belt and to be removed by the exhaust system located at one end of the sander belt.
The particular lubricating, low friction, adherent binder graphite compositions illustrated above proved not only effective upon first using in the sanding operation, but continued to be completely effective throughout the life of the sander belt. Other types of graphite, such as flake or vein were not so effective in that they did not adhere to the binder or the belt under the rugged use conditions associated with such sanding operations. A preferred powdered amorphous graphite for use in the present invention is that identified as Dixon 620, sold by The Dixon Crucible Co., Jersey City, New Jersey.
Silicone fluids also may be mixed directly with the graphite without any hydrocarbon diluents where coating methods permit use of a more viscous composition.
While specific details of preferred embodiments have been set forth above, it will be apparent that many changes and modifications may be made therein without departing from the spirit of the invention. It will therefore be understood that what has been described herein is intended to be illustrative only, and is not intended to limit the scope of the invention.
' What is claimed is:
1. An abrasive sander belt having a surface coating on the side, opposite to that containing the abrasive material comprising a lubricating, low-friction, adherent binder and powdered amorphous graphite.
2. The sander belt of claim 1 wherein said binder is selected from the group consisting of paraffin Wax and silicone fluids.
3. An abrasive sander belt having a lubricating, lowfriction, adherent surface coating on the side opposite to that containing the abrasive material comprising a mixture of 19.4 parts of silicone fluid, 51.4 parts of powdered amorphous graphite and 29.1 parts of a high boiling aliphatic hydrocarbon diluent.
4. An abrasive sander belt having a thin, lubricating, low-friction, adherent surface coating on the side opposite to that containing the abrasive material including from 0.5 to 1.5 grams of powdered amorphous graphite per square foot of the sander belt.
References Cited by the Examiner UNITED STATES PATENTS 2,356,367 8/44 Wright 2s2 29 2,624,160 1/53 Harper -51-141 2,700,623 1/55 Hall 252 12 2,854,351 9/58 Wilson 252-29 3,047,526 7/62 Stephens 252-29 x FOREIGN PATENTS 8,598 4/84 Great Britain. Of 1884 LESTER M. SWINGLE, Primary Examiner. FRANK H. BRONAUGH, Examiner.