US2858651A - Polishing belts - Google Patents

Description

No'v. 4, 1958 R. H. sHAw al-AL POLISHVING BELTS Filed Aug. 8, 1957 mmm :l

United rates POLISHING BELTS Ralph H. Shaw and Ralph H. Shaw II, Middletown,

Conn., assignors to rl`he Shaw Belting Company, Mlddletown, Conn., a corporation of Connecticut Application August 8, 1957, Serial No. 677,062

6 Claims. (Cl. 51-1SS) This invention relates to polishing belts, particularly for use on power driven machines for lpolishing metal or other parts, the term polishing, unless otherwise stated, being here intended to include operations with polishing agents, similar grinding operations, as ywith line abrasives, and polishing operations without such agents or compounds, e. g. of the nature ofor similarvto bufl'ing It is common to use polishing belts on power .driven machines for various purposes, for example, to Iproduce ak highly polished finish on plated metalparts, other metal workpieces, waxed Wooden articles, or the like. vSuch belts, Whether of simple Vor larninated structure, have a face which is .to be rubbed against the part being polished and which may be treated, coated or otherwise specially characterized for the polishing function. Thesimplest type of grinding belt comprises a substantially inextensible fabric support layer, coated on one face with abrasive in a suitable solid carrier. Certain more durable belts comprise a plurality of mutually secured, identical -textile fabric layers; a renewable coating can be applied -to .one face, e. g. a coating of abrasive Vor polishing particles in a water-soluble adhesive. Another class of belts comprises those with a napped fabric face, -or with a vsurface layer of specially porous or retentive character, which are used with a polishing agent, e. g. rouge or tripoli, applied to the belt while running. Some belts, notably those having a fabric face layer with a nap, i. e. either of felt like character or of woven textile having a nap, are adapted to Vbe used either with such polishing agent (applied from the conventional block or stick) or without a polishing agent, in which case they may be said to run dry. -One such nap-surface `belt consists of a strip of thick multi-ply Wool vtextile woven as a single structure and having a highly napped or felt-.like polishing face.

In the .construction and use of polishing belts, a number of problems arise, especially in the case .ofnapsurfaced belts. For instance, the lpolishing operation necessarily produces heat at the pointrof contact between the belt and the piece being polished. Considerable skill or care may be required in operating the machine in order to avoid burning or clouding of the metal finish.

Another problem frequently encountered in connection with such operations employing various types of belts is the difficulty `of polishing surfaces having contours other than at planes, for example, round ,or half-round surfaces.

` With polishing belt structures .of ,the prior art, Le. g. those used with an applied polishing agent, the life .of the belt ,is limited by a tendency of the polishing material to fill the pores and interstices in the face layer, eventually forming a hard, glazed surface which-does not ,eifectively perform the required polishing action, but on kthe other hand tends to scratch the surface.

In polishing operations of the type described, a distinction is made between supported and unsupported operations. In a supported polishing operation, the belt is backed up by a Support member opposite .the paint '2,858,651 4-llatented Nov. 4, 1958 where the face layer engages the workpiece. In an unsupported operation there is no such backing up of the belt at the point where it engages the workpiece. The supported operations may be backed up by a wheel which rolls with the belt or they may be backed up by a flat platen over which the belt runs. One present practice is to run smooth abrasive belts, for example of simple, relatively thin` character, over ribbed or serrated backing Wheels in order to provide local changes in elevation of the belt surface whereby only parts .of the belt would contact the work. This enables lgthe operator to polish more readily the round contouredv parts. It also enables the belt -to run somewhat cooler,I since the areas of the belt between the ribs do not contact the workpiece with such great force. In thecase of flat platen belt grinding, it has been-suggested to provide a moving ribbed platen as a backing up: member for the belt. However, such a platen structure: must be fairly complicated and introduces considerable expense in the construction of the grinding machine. Moreover, ribbed back-up wheels or platents have little or no function with multi-layer belts, or with multipleply belts such as the nap-surfaced structures mentioned above, which have been made relatively thick and heavy for durability or strength and tend to be correspondingly insensitive at their polishing faces to the configuration of the back-up means.

An object of the invention is to provide an improved belt for use in grinding and polishing operations.

Another object is to provide an improved belt ofthe type described which is internally constructed to provide a ridged effect at its face surface, e. g., as by having at least one internal lamination comprising raised ribs.

The foregoing and other objects of the invention are attained in the structure described herein by providing a belt including one or more supporting layers, an intermediate layer consisting of spaced parallel ribs, and a face layer. Such layers may be separate elements bonded together, or may be originally made in part yor in whole as an integrated structure, e. g. by multipleply weaving. A special feature of the invention is the provision of such a belt having a surface, for polishing action, of a class defined above, i. e. which will readily hold a polishing agent such as is applied while the'belt is running. To particular advantage, the belt is characterized by a face layer which has a nap surface, such term being here intended to mean a surface having a felt-like or flannel-like nature, or having surface fibers or yarns arranged in any other way, whether as a freestanding nap or otherwise, to have some freedom of motion relative to the fabric as a whole; that is to say, such surface can be dened as one which provides a soft,

resilient, absorbent face that can retain the polishing' agent and that can alternativelyv be run dry for th polishing operation. f

Such belts have valuable advantages, including certain advantages which have heretofore been sought by the use of ribbed back-up means (but achieved only in part and only in some cases), and which have not been attained in' any way with nap-surfaced belts such as heretofore available.

Thus the described belts ,are found, in general, to .afford improved results in .avoiding excessive heating effects, and also in effectiveness of operation on workpieces of difficult contour. The last-mentioned advantage appears to be promoted by a preferred and specific feature of the invention, i. e. the provision of the ribs along lines bearing ,an acute angle relationship to the sides of the belt,`

for example ribs running entirely diagonally across the belt, or in a herringbone `or other zig-zag pattern. The polishing action of nap-surfaced belts embodying .the iu-v vention and thus having a surface contour of elevated,

ribs or ridge-like areas mutually separated by perceptible valleys or depressions, is found to be unusually superior, either with or without the application, during running, of polishing compounds such as rouge or tripoli. In either type of use the actual polishing seems to be more effective or to be attainable more rapidly, and at the same time the belts have an exceptionally long life under normal conditions.

Not only are the belts particularly suited to operate on articles having curved surfaces, but they are specially effective where it is desired to reduce or relieve sharp edges, minor burrs or the like in the case of polishing operation on fiat-surfaced castings, stampings or similar Workpieces having intricate boundaries or outlines of the surface to be polished. Whereas it has been necessary to make some prior belts from sections of fabric woven in a large tubular shape, i. e. to avoid splicing seams, the present structures allow splices to be located in the diagonalvalleys or depressions whereby all irregularity of belt travel over supporting rollers is avoided and belts may be of any. desired length rather than limited to the circumference of available tubular-weave textiles. The various advantages appear to be well realized both with round and flat back-up means, e. g. either simple, smooth rollers or fiat platens, or indeed, if desired, with unsupported operation at the polishing locality.

Finally, in using polishing compounds the ribbed belts appear to have a considerably longer life than smooth surfaced elements, with respect to loading, clogging or caking of the surface with the applied compound. At the same time the general useful life is prolonged, in that as the ridges or ribs tend to compact and become less prominent, relatively fresh portionsof the polishing f I ce become effective.

Other objects and advantages of the invetnion will become apparent from a consideration of the following description and claims, taken together with the accompanying drawing.

In the drawing:

Fig. l is an elevational view showing a belt grinding machine of the fiat platen type, and equipped with a belt constructed in accordance with the present invention;

Fig. 2 is a View partly in plan and partly in several sections formed by the breaking away of the several laminations, showing 'a belt constructed in accordance with the invention;

Fig. 3 is a cross-sectional view taken on the line III-HI of Fig. 2; and

Fig. 4 is a fragmentary View similar to the plan portion of Fig. 2, illustrating the uneven wear characteristics which are produced in a belt constructed in accordance with the invention.

Referring to Fig. l, there is shown a polishing machine including a frame 1, supporting three idler pulleys 2 and a drive pulley 3, driven by a motor, not shown. A belt 4 runs over the several pulleys. It should be understood that the front ends of the pulleys, as viewed in the drawing, are supported by another frame (not shown), similar to the frame ll, which has been omitted to clarify the drawing. On its lower horizontal traverse, as it appears in' the drawing, the belt runs over a fiat back-up platen 5. .lust below the belt 4, there is shown a workpiece 6 supported on an anvil 7.

The details of construction of the belt 4 are illustrated in Figs. 2 and 3. The side of the belt which runs against the pulleys is formed by a layer 8 of suitable supporting material, such as cotton drill. This material may be coated or sized to give it any desired characteristics, particularly a good friction grip on the pulleys 2 and 3. For some operations, a considerably heavier material, such as webbing, may be used. On top of the inner layer 8, there is placed a layer 9 of heavy Orlon. This Orlon, which may be used in a basket weave, is used to provide high longitudinal strength while minimizing longitudinal stretch as much as possible. .Several other materials may 'be used in place of Orlon, all of them, including Orlon, being common in the art. lf the backing layer 8 is of effectively strong, non-stretch, i. e. inextensible material, or if some stretch can be tolerated, the layer 9 may be omitted; it represents, however, a convenient means for reducing the stretch factor to a very low value, as is desired in many cases.

On the outer side of the reinforcing layer 9 are provided a plurality of wide flat ribs 10. The ribs 10 are preferably made of felt. They may be alternatively made of woven cotton or other materials which are pliable and somewhat compressible. The ribs are set at au angle, preferably 45, to the longitudinal axis of the belt, to minimize any tendency to vibrate or chatter during operation. Over the top of the ribs and the intervening areas of the reinforcing layer is mounted a face layer 11 of woven wool felt. Some other materials, such as mixtures of cotton and wool or nylon and wool or heavy cotton flannel or other material having the desired surface characteristics, may be used, but woven all wool felt is greatly preferred at present.

The several layers and the ribs 10 are bonded together during manufacture by a suitable bonding agent, for example, rubber cement or one of the synthetic substitutes therefor. Neoprene cement is presentlypreferred. After the layers and ribs are assembled and bonded together, they are firmly fastened by a plurality of parallel rows of stitching 12, extending longitudinally of the belt and closely spaced from side to side of the belt.

A present method of assembly, for instance, involves applying a coating of the self-drying bonding cement to the layer 8 for adherence of layer 9 thereto, then to the layer 9 for adherence of the ribs 10 and finally again over the composite surface of the ribs 10 and exposed intermediate faces of layer 9, for adherence of the face layer 11. Alternatively other bonding means may be employed, as with a vulcanizable rubber compound, so that on completion of the assembly, it can be subjected to vulcanization to yield an essentially integral structure joining the outer layers 8 and 11. In appropriate cases the stitching 12 may be omitted. Although another method of construction involves weaving the ribs into the fabric, as by constituting at least some of the several layers as plies or sets of plies of a multiple-ply textile with the ribs formed, for example, by spaced internal groups of thick cords (and the whole then cut on the bias), the illustrated arrangement of separate, mutually bonded layers and pieces is an effective and presently economical type of structure.

In operation, the surfaces of the face layer 11 which are over the ribs 10 arel the first ones to Wear. As illustrated in Fig. 4, the belt wears in a plurality of parallel strips as shown at 13. Each strip 13 is surrounded by a marginal area 14. On each revolution of the belt, each strip 13. becomes a little wider and a small area ofnew material comes into play at the marginal area 14. The new material has a substantial nap projecting which is highly desirable for eicient polishing. Since new material is always being presented, and any material which might tend to become lled with polishing agent and glazed is Worn away, the life of the belt is thereby increased. The belt tends to run cooler, since only the strips 13 over the ribs are heated by contact with the workpiece andthe parts of the belt between the strips 13 remain substantially at room temperature. Since the heated areas of the belt are limited in extent, and are surrounded by unheated areas, then during the nonworking portion of the path of travel the heat in the heated areas is conducted to the air or to the intervening portions, so that the belt runs substantially cooler.

It has been found that the characteristics of the belt, as to improved polishing action as well as to cool running and as to the carrying of a polishing agent, are very good when the space between the ribs is of the same order of magnitude as the rib Width. Thus in the illustrated embodiment the space between ribs is approximately equal to the rib width.

The ribbed belt as shown and described above is highly effective for polishing irregular, round and half-round surfaces. The projecting ridges of the face layer 11 above the ribs are effective to project into and engage such irregular surfaces for polishing.

The dimensions of the ribs, and the ratio between rib width and rib thickness, may be varied widely to meet various problems encountered in use. By way of example, it has been found that a width of and a thickness of 1A" gives good results in most common situations.

The ribbed belt described above may be used for a variety of polishing or grinding operations and brings to such operations all the advantages which have been explained hereinabove.

vWhile We have shown and described a preferred embodiment of our invention, other modifications thereof will readily occur to those skilled in the art and we therefore intend our invention to be limited only by the appended claims.

We claim:

1. A laminated endless polishing belt comprising a reinforcing layer of material having high tensile ,strength and low stretchability longitudinally of the belt, a plurality of spaced parallel ribs of flexible, compressible material, said ribs being bonded to said reinforcing layer and extending angularly with respect to the longitudinal direction of said belt, and a face layer of textile material bonded to the ribs, and to the areas of said reinforcing layer between the ribs.

2. A polishing belt comprising a plurality of mutually fastened layers, including a continuous back layer, an intermediate layer comprising a plurality of spaced parallel felt ribs, and a continuous face layer over the ribs to be used for polishing operation.

3. A polishing belt comprising a plurality of mutually fastened layers, including a continuous back layer, an intermediate layer comprising a plurality of spaced parallel ribs of flexible material, said ribs extending angularly with respect to the longitudinal direction of the belt, and a continuous face layer over the ribs to be used for polishing operation.

4. A polishing belt as dened in claim 3, in which said ribs are straight and parallel, and diagonal with respect to the longitudinal direction of the belt.

5. A polishing belt as defined in claim 3, in which said ribs form a herringbone pattern.

6. An endless belt comprising a plurality of mutually fastened layers, including a continuous back layer, an intermediate layer comprising a plurality of spaced parallel ribs of leXible material, said ribs extending angularly with respect to the longitudinal direction of the belt, and a continuous face layer over the ribs.

References Cited in the file of this patent Great Britain Sept. 23, 1953

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