US2189754A - Endless grinding and polishing belt - Google Patents

Description

Feb. 13, 1940. CHERRINGTQN 2,189,754

ENDLESS GRINDING AND POLISHING BELT 'Filed'April 29, 1958 INVEN TOR.

'By QM ATTORNEY Patented Feb. 13, 1940 UNITED STATES P'A 'I'IEINT OFFICE 2,189,754 ENDLESS GRINDING AND POLISHING, BELT George n. Cherrin'gton, Pittsburgh, Pa. Application April 29, 1938, Serial Nb. 204,946

This invention relates to improvements --in endless belts and particularly to that type-used for grinding and polishing sheet material.

As is well known in the'art, belts forg'rinding and polishing sheet material are usuallyof the wide and. endless type and made of paper coated with any suitable abrasive. To produce an evenly and uniformly ground or polished surfaceof the sheet material, these belts are made out of one piece of paper material with the adjacent ends matched together at a bias or otherwise and then securely united with adhesive. Such belts are generally of considerable width in order to operate over the full width of the sheetmaterial which is to be ground or polished. 1 v

Belts of this kind traverse at a high rate 0 speed and since the same is made of strong paper and the adjacent ends glued or cemented together, the pressure of the belt exerted against the sheet material must not be too great in order to avoid tearing of the belt at the joined ends.

The improved construction of the belt made in accordance with this invention considerably differs from the belts now in use for that purpose and it is therefore one of the main objects of this invention to produce a wide and endless belt which has no cross-joined ends.

Another object of this invention is to produce a wide and endless belt which is built up in spiral fashion of two or more laps of a continuous piece of exteriorly coated abrasive paper tape.

Still another object of this invention is to produce a wide and endless belt which is built up in spiral fashion of two or more laps of a continuous piece of exteriorly coated abrasive paper tape, the edges of which being scarfed and glued together to form a cylindrical endless belt.

Another object of this invention is to produce a grinding or polishing belt which possesses a greater strength than belts heretofore constructed.

Yet another object of the invention is to produce a grinding or polishing belt which will not cause creeping on the pulleys over which the belt is trained.

A further object of the invention is to produce an endless grinding and polishing belt which is especially adapted for rough grinding at a much higher speed than heretofore possible.

A still further object of this invention is to produce an endless cylindrical grinding and pol-'- ishing belt which will grind or polish the surface of sheet material more uniformly.

Yet another object of this invention is to produce an endless cylindrical grinding or polishing belt which has no cross-seams to tear.

With these and other objects in view the invention will be better understood from the 01- lowing detailed description taken in connection with the accompanying drawing wherein:

Figure '1 illustrates diagrammatically an endless grinding or polishing belt trained over a pair of pulleys.

Figure 2 is a top plan view thereof.

I Figure 3 is an enlarged sectional view along line 3-3- in Figure 1.

Figure 4 shows an exaggerated, isometric and sectional view through a paper-tape as used in this invention, coated at the exterior surface with an abrasive and polishing agent with both edges scarfed in a manner as shown, the dot and dash lines indicate the original outline of the tape before scarfing.

Figure 5 is a perspective view of a reel of abrasive tape as may be used in this invention.

Figure 6 is an enlarged sectional view illustrating the method of joining the scarfed edges of the abrasive tape in accordance with this invention.

Similar reference numbers indicate corresponding parts in all figures.

Referring now to Figure 5 of the drawing, I have shown a continuous piece of a strong paper tape II wound on a reel l2. This tape is coated at its exterior surface I3 with an abrasive agent I4, such, for instance, as particles of sharp grained sand or emery, varied in size to give a fine or coarse surface.

The exterior surface, as well as the under surface I5 of said tape II may bescarfed at the edges in a manner as indicated by the numerals I6 and II respectively and best shown in Figures 3 and 4.

These scarfed edges I6 and I! may be readily scarfed by means of a pair of oppositely located grinding wheels I8 and I9, operating, at the desired angle of the scarf, along the edges of said I tape I I. Of course, it is obvious that this is only one of many ways of accomplishing the desired result.

After the tape II has been properly scarfed by any suitable method, it is wound upon another reel and then finally, in spiral relation, wound about a pair of spaced drums (not shown) which predetermined the desired length of the collapsed and finished belt.

As the scarfed tape II is wound, in spiral fashion, around the drums the adjacent scarfed edges l6 and I1 are glued or cemented together 2. to form an even joint, thus producing a wide belt from a relatively narrow tape.

In Figure 6 there is shown an enlarged sectional view of an edgewise jointed abrasive paper tape in which a slight depression 20 over the joint 2| remains and which is caused by rollers or other mediums by means of which the glued scarfed edges may be pressed together to form a tight joint.

The depression 20, of course, exists over and along the entire continuous and spiral seam 22 of the finished belt, thus a continuous spiral depression or groove is formed which greatly assists in disposing of the metal and emery dust removed when grinding sheet material without clogging up the natural gaps of the abrasive belt.

It will be seen that the herewith described improved abrasive endless belt is particularly adaptable as a grinding and polishing medium for sheet metal because it will grind or polish at a much greater speed than heretofore attained and, since no cross-seam exists the belt cannot tear at the seam as is frequently the case with belts having such cross-seams.

From the foregoing description taken in connection with the accompanying drawing, the construction of the belt and the method of producing the same will be readily apparent to those skilled in the art to which the invention appertains, and while describing the principle of operation of the invention together with the device which is now considered to be the best embodiment thereof, it is to be understood that various changes in the form, proportion and the minor details of construction may be resorted to without departing from the principle or sacrificing any of the advantages of the invention as defined in the appended claims.

I claim:

1. In combination with a pair of pulleys spaced from each other, an endless belt for grinding or polishing sheet metal trained about said pulleys with portions extending between the pulleys, said belt comprising a narrow elongated strip of thin flexible material provided along one side edge with an outer beveled face and along its other side edge with an inner beveled edge, said strip being coiled to provide spirally extending belt sections disposed in side by side relation to each other with their inner beveled edge faces overlapping their outer beveled edge faces for the full Width thereof and adheringly secured in face to face engagement with each other, the end convolutions of the strip being tapered to provide the belt with parallel side edges and form a belt of even width throughout its length.

2. In combination with a pair of pulleys spaced from each other, an endless belt for grinding or polishing sheet metal trained about said pulleys with portions extending between the pulleys, said belt comprising an elongated strip of flexible material having an inner soarfed edge face along one side edge and an outer scarfed edge face along its other side edge, said strip being coiled to provide convolutions disposed in side by side relation to each other to form a composite belt of predetermined length and width and having their inner scarfed edge faces adheringly secured upon the outer scarfed edge faces in flat face to face engagement therewith, and abrading material upon the outer face of the belt.

GEORGE H. CI-IERRINGTON.

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