US2637956A - Coated abrasive belt - Google Patents

Description

May 12, 1953 w. G. NUESSLE 2,637,956 COATED ABRASIVE BELT Filed March 28, 1952 max/Wm? Patented May 12, 1953 COATED ABRASIVE BELT Walter G. Nuessle, St Paul, Minn, assignor to Minnesota Mining & Manufacturing Company, St. Paul, Minn., a corporation of Delaware Application March 28, 1952, Serial No. 279,037

3 Claims.

This invention relates to coated abrasive articles, and, more particularly, to such articles in the form of an endless belt. The use of coated abrasive belts has been extended markedly in recent years, partially through the development of improved grinding devices which include a contact roll for resiliently, yet firmly, supporting the abrasive belt againstthe workpiece while the former is moving at high speeds. Such uses of abrasive belts have quite largely been confined to abrading substantially fiat surfaces, such as steel sheets, fiat glass, glass edges, and the like.

An object of this invention is the provision of a coated abrasive belt that may be employed not only to abrade and polish fiat surfaces but also may be supported upon a contact roll or platen to abrade and polish curved surfaces of small radii, such as, for example, the recessed areas of cutlery, trigger guards, and the fillets of jet blades, where the edge of the conventional abrasive belt would undercut or rapidly become frayed.

Coated abrasive belts known to the art are provided with straight edges. I have found that a workpiece having a curved surface of a small radius may be abraded or polished in a highly satisfactory manner by the use of coated abrasive belts having scalloped or pinked edges, as hereinafter set forth. A further advantage of my improved belt lies in the fact that the same belt may be employed in grinding both flat and curved surfaces, and thus it is not necessary to change the belt used in grinding the foil surface of a jet blade when it is desired to abrade the curved root section of the blade.

The invention will be readily understood from the following description in connection with the accompanying drawing, in which:

Figure 1 is a perspective view of a portion of the improved abrasive belt mounted upon a contact roll, forming a part of a grinding device (not shown) and in position to abrade the curved root section of a jet blade as the workpiece;

Figure 2, a plan view or a portion of my improved coated abrasive belt;

Figure 3, an enlarged front elevational view, partly in section, of the elements shown in Figure 1;

Figure 4, an enlarged side elevation of my improved belt mounted upon a contact roll, with the workpiece removed.

Referring to the drawing, in Figures 1 and 3, my improved abrasive belt I is shown mounted upon a contact or presser roll II in position to abrade the curved fillet ll of a jet blade 13. The contact roll is preferably provided with sloping or tapered peripheral edges l4, and is otherwise of conventional construction. It has a somewhat resilient surface to afford a firm, yet yielding, support for the abrasive belt when the latter is engaged with the workpiece. The contact roll H may be of the type disclosed in Herchenrider Patent No. 2,145,418 of January 31, 1939. The contact roll H is one element of a conventional grinding device (not shown) of the type in which a flexible abrasive belt is trained over a contact roll and a driven roll and on which the belt may be driven at high speeds. Grinding and polishing devices of the general type disclosed in the above-mentioned Herchenrider patent are suitable for use with my improved abrasive belt. The belt may also be employed with a permanent shaped back-up support, such as aformed platen.

The belt I!) comprises a flexible backing l5 coated upon one surface with an adhesive binder I6 and carrying a layer 1'! of abrasive particles embedded in the binder. The backing may be formed of cloth, such as stretched, pre-shrunk drill cloth, vulcanized fiber, paper, combinations of cloth, fiber or paper, or similar flexible, dimensionally stable material. The adhesive binder may comprise one or more coatings of glue or of a synthetic resin, such as modified phenolic resins or a drying-oil-modified alkyl resin, for example, of the type disclosed in the Guth Patent No. 2,202,756, or of combinations of glue and resin coatings. The abrasive grits are those previously employed in the coated abrasive industry, such as silicon carbide or aluminum oxide. Endless belts may be made from the coated and cured sheet material by slitting it to the proper width and skiving and splicing together the ends of a strip of the desired length, in accordance with well-known practice.

After the coated web has been cured and slit to strips of the desired width, and preferably before the ends of the strips have been spliced, the coated strips are passed through a pinking device to cut out, in one or both edges of the strips, suitably shaped indentations l8, regularly spaced between intervening ridges l9. The size and spacing of the indentations l8 may vary in difierent belts, dependin upon such variables as thewidth of the belt, the diameter of the contact roll upon which the belt is to be mounted, the shape and radius of curvature of the workpiece and the speed of belt travel. At higher speeds a belt having fewer indentations for a given length can be satisfactorily employed than when the belt is driven at slower speeds. It is particularly important that the ridges or scallops [3 are of such shape and size that they will not overlap each other when bent over at angles approaching 90 when engaged with the work. Otherwise the workpiece may be marred or abraded irregularly. The curved fillets of jet blades, as shown in the drawing, have been satisfactorily abraded with a belt of an inch in width (from crest to crest) and mounted on a contact roll of 2%; inches in diameter. This belt was provided with four indentations, of a depth of approximately of an inch, per linear inch. The distance between adjacent lands was approximately of an inch, and, as shown, the shape of the ridge l5 and intervening valleys 01' indentations l8 approximated the curve of a sine wave. On a wider belt to be used on a larger contact roll, the indentations would preferably be deeper than of an inch. Likewise, the shape of the indentations and intervening ridges may be modified and they may be approximately square or oblong, or may be saw-toothed in shape.

As shown in Figures 1, 3 and 4, as the im proved belt passes over the contact roll and bears against the workpiece, the lands or ridges l3 coated with abrasive particles are bent from the plane of the central portion of the belt and conform to the curvature of the work. As indicated in the drawing, it is essential that the ridges be so shaped and spaced that they do not overlap each other when bent again-st the curved Workpiece. If both edges of the belt are scalloped, a ridge !9 on one edge is preferably disposed opposite to a valley IS on the other edge.

While the invention is preferably employed in abrasive articles, in the form of coated abrasive belts, it is apparent that my improved abrasive material has utility in the form of discs, fiat sheets or strips, etc.

Having described various embodiments of my invention for purposes of illustration, but with out intent to be limited thereto, what I claim is as follows:

1. A flexible abrasive belt suitable for the abrading of curved surfaces comprising a flexible, dimensionally stable backing, an adhesive coating on one surface of said backing, and a multiplicity of abrasive particles embedded in said adhesive coating, at least one edge of said belt being provided with a series of evenly shaped and spaced indentations, the intervening ridges being coated on one surface thereof with abrasive particles and being spaced in such manner that they do not overlap each other when bent to the work.

2. A coated abrasive belt suitable for the abrading of curved surfaces comprising a waterresistant, dimensionally stable backing, an adhesive binder coated on one surface of said backing and a multiplicity of abrasive particles embedded in said binder, at least one edge of said belt being scalloped to provide indentations and intervening lands, the edges of said lands and indentations forming a curve of the natureof a sine wave, the lands being coated on one surface thereof with abrasive particles.

3. A coated abrasive belt comprising a flexible, water-resistant, dimensionally stable backing, an adhesive coating on one surface of said backing, and abrasive particles embedded in said adhesive coating, both edges of said belt being provided with regularly spaced and shaped indentations, the ridges intervening said indentations being coated on one surface thereof with abrasive particles and the ridges on one edge of said belt being disposed opposite to the valleys on the other edge of said belt.

WALTER G. NUESSLE.

N 0 references cited.

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