US3545142A - Abrading implements - Google Patents

Description

Dec. 8"1970 w. E. suLLENBl-:RGER 3,545,142

ABRADING IMPLEMENTS Filed May 24, 1968 INVENTOR:

United States Patent 3,545,142 ABRADING IMPLEMENTS William E. Sullenberger, Rte. 1, Box 127E,

Linden, Pa. 17744 Filed May 24, 1968, Ser. N0. 731,879 Int. Cl. B24d 9/02 U.S. Cl. 51-374 7 Claims ABSTRACT F THE DISCLOSURE A rotary abrading implement composed of a mandrel having a radially expansible drum upon which a circumferentially endless abrasive band is axially insertable. The drum is characterized by a concentric outer band-supporting surface formed from axially extending flexible lingers cantilevered from the outer end of the mandrel and extending axially inwardly from said mandrel end. Centrifugal force generated by rotation of the drum radially expands the lingers against the intermediate inner surface of the band to anchor it in position. Additional anchorage is produced by effecting a relatively lesser expansion of the insertion marginal band end concurrently with said expansion at the intermediate band portion.

This invention relates to abrading implements and more particularly to a rotary drum having means for securing a circumferentially endless abrasive band thereover in a unique manner.

Heretofore, various types of flexible drums have been employed for removably supporting endless abrasive bands thereover in tensioned position. Patents Nos. 2,207,439 and 3,027,692 disclose typical examples. In such conventional types, the band is secured in position by an expansible underlying drum, made of rubber or similar llexible material, against the inside surface of the band.

Although the conventional liexible or resilient drums may be perfectly concentric with respect to the axes of rotation before expansion, the subsequent expansion necessary to hold the abrasive band thereover often produces eccentric bulges at the abrading periphery which causes the band to wear irregularly and also sets up highly objectionable vibrations during operation.

It is therefore an object of this invention to provide an abrading implement devoid of the aforementioned objections.

It is another object of invention to provide an abrading implement characterized by a rotary drum or band holder having a concentric band-receiving periphery formed upon axially extending cantilevered lingers s0 that the centrifugal force generated during rotation of the drum will radially expand the linger surfaces outwardly into engagement with the interior of the band to anchor the latter in position.

It is another object of invention to provide an abrading implement of the type described in the immediately preceding paragraph wherein the lingers are provided with means for expanding the insertion marginal end of the band a lesser amount and concurrently with the radial expansion of the intermediate band portion under the influence of said centrifugal force to thereby additionally anchor the band in position.

It is another object of invention to provide an abrading implement Which is simple in construction, eliicient in operation, and relatively inexpensive to manufacture.

'Some of the objects of invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which,

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FIG. l is an elevation of the invention, showing a circumferentially endless abrasive band mounted upon a band-receiving drum or holder;

FIG. 2 is a view of the left-hand end of FIG. l;

FIG. 3 is a view of the right-hand end of FIG. l;

FIG. 4 is an isometric view of the endless abrasive band adapted to be removably inserted over the holder shown in FIGS. l and 2;

FIG. 5 is a view similar to FIG. 1, but showing the band in section and the band-receiving surface of the holder in elevation;

FIG. 6 is a sectional view taken along line 6 6 in FIG. 1;

FIG. 7 is an enlarged fragmentary view of the upper portion of FIG. 6, showing the radially expanded positions of the linger and the band when subjected to centrifugal force generated by rotation.

Referring more specifically to the drawings, the numeral 10 broadly denotes a rotary abrading implement or tool comprising a mandrel 11 having integral mounted on its outer end as at 11a a drum 12 upon which a circumferentially endless abrasive band 13 is removably mounted. Mandrel 11 is adapted to be fastened in a machine-driven chuck (not shown) when it is desired to rotate the tool 10 during an abrading operation.

From using endless bands such as indicated by reference character 13, it has been found that the inside diameter for a given band size varies a few thousandths of an inch, depending upon the band grit. For example, a one-inch Llll-grit band tends to be oversize and therefore lits loosely over a one-inch drum. The oversize progressively decreases as the grit number increases; and thus When a slight 12C-grit band is used on `the same mandrel, the fit is tight. The drum according to the present invention is designed to compensate for such variations of the band diameter whereby a range of slightly differing band diameters may be used on the same drum.

Likewise, the roughness of the band ends or yaxial edges progressively decreases as the grit of the band increases. For example, a 40-grit band has a heavy edge, Whereas, a l20-grit band has a slight edge. Apparently, the various degrees of edge roughness are produced when the bands 13 are severed from a longer stock during manufacture.

The right-hand end of mandrel 11 (FIG. 6) penetrates bottom 12a and is provided with an enlarged head 11a which is countersunk in the outer face of the bottom. A Washer 15 on the mandrel is pressed against the inside face of bottom 12a by means of nut 16 threadably secured upon the mandrel.

By observing FIG. 6, it will be noted that drum 12 is cup-shaped and comprises: said bottom portion or disk 12a, a continuous cylindrical Wall 12b integral with and extending axially from the bottom, and a plurality of axially extending and circumferentially arranged lingers 18 integral with and rigidly cantilevered from the wall. These lingers are separated from one another by slots 19. At the respective junctions of fingers 18 with wall 12b, holes 19a are provided to decrease the cross-sectional areas of the lingers which increases linger flexibility and prevents breakage.

The outer peripheral surfaces of lingers 18, Wall 12b, and bottom disk 12a are concentric with mandrel 11 and, taken together, form a tubular surface of revolution for receiving endless band 13, said linger surfaces being knurled as at 18a to increase the bond between the fingers and an inserted band.

Each linger 18 is provided with a shoulder 20 at its free end which serves as a stop against which the end of an inserted band abuts when squarely positioning the band on the holder. Adjacent the shoulders 20 is a circumferential groove 21 formed in all of the fingers, said groove serving to relieve or lessen the tension upon the rough end of the band when in inserted position.

During operation, the centrifugal force generated by rotation causes the fingers 18 to expand outwardly from an approximate normal position indicated by dotted line 25 in FIG. `6 to the bold line position to grip the inside surface of the band. Concurrently with this expansion, the rough edge or end 13a of the band expands a lesser amount and sinks into groove 21 thereby additionally securing the band upon the outer drum surface.

The above-described abrading drum aords the following advantages:

(a) Longer life of drum;

(b) Longer life of band;

(c) Less wear and tear on the moving parts in hand-operated machines;

(d) Endless bands will not fly apart or explode;

(e) Less 'body pressure needed to perform a grinding job and consequently, less fatigue of the operator.

The drum bottom portion 12a is tapered or radiused inwardly as at 12a` in order to facilitate change of bands 13.

In the drawings and specification a preferred embodiment of the invention has been disclosed, and although specific terms are employed, these are used in a generic sense and not |for purposes of limitation, the scope of invention being defined in hte Ifollowing claims.

I claim:

1. A rotary abrading implement comprising a mandrel, a circular disk secured at the outer end of said mandrel, a plurality of resilient fingers, means for rigidly cantilevering one end of each of said fingers at the circumference of said disk, said fingers extending axially inwardly from said mandrel end and positioned in radially spaced relation to the mandrel, the outer surfaces of said fingers forming a tubular surface of revolution substantially concentric with the mandrel, and a circumferentially endless abrasive band insertable over said tubular surface, whereby the centrifugal force generated by rotation will radially expand said finger surfaces radially outwardly from the mandrel and against the inside surface of said band to anchor the latter in position.

2. An abrading implement as defined in claim 1 wherein said cantilevering means includes a cylindrical wall portion integral with the circumference of said disk and with said cantilevered finger ends, the outer surface of said wall portion being concentric with and forming an extension of said surface of revolution.

3. An abrading implement as defined in claim 2 wherein said disk is bevelled at the intersection of its outer face and the axial projection of said outer wall surface to thereby facilitate insertion of said band thereover and onto said surface of revolution.

4. An abrading implement as defined in claim 1 and further comprising means integral with at least one of said inward linger ends and axially abuttable by the insertion end of said band for limiting the axial position of the latter on said finger surfaces.

5. An abrading implement as defined in claim 4 and further comprising means for relieving said insertion end portion of said band from radial expansion, said means including a circumferential groove in said linger surfaces underneath the abutting band end portion whereby the latter will sink into the groove upon radial expansion of said fingers.

6. An abrading implement as defined in claim 1 and further comprising means including a circumferential groove in said outer finger surfaces and substantially coinciding with an inserted band end for relieving the latter from radial expansion by said fingers.

7. An abrading implement as defined in claim 1 wherein each of said fingers has a reduced cross-sectional area adjacent its cantilevered end to thereby increase finger iiexibility.

References Cited UNITED STATES PATENTS 2,058,467 10/ 1936 Knowlton 51-374 2,076,776 `4/ 1937 Hadaway 51-374 OTH'ELL M. SIMPSON, Primary Examiner

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