US3670463A

US3670463A - Coated abrasive cones

Info

Publication number: US3670463A
Application number: US121918A
Authority: US
Inventors: Warren E Christian
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1971-03-08
Filing date: 1971-03-08
Publication date: 1972-06-20
Anticipated expiration: 1989-06-20

Abstract

A flexible abrasive tool having a conical shape is provided with tear means whereby the tool can be separated, if desired, into two or more abrasive tools of the same conical shape but of lesser desired vertical height.

Description

United States Patent Christian 1 June 20, 1972 COATED ABRASIVE CONES [72] Inventor: Warren E. Christian, Troy, N.Y.

[73] Assignee: Norton Company, Troy, N.Y.

[22] Filed: March 8, 1971 21 Appl. No.: 121,918

52 user ..s1/394,51 3s0 s1 lnLCl. ..B24d 17/00, B24d11/00 5s FieldofSearch ..5l/394,358,407,380,381,

51/384, 397, 407; 229/21, 51 DB; 206/56 R References Cited UNITED STATES PATENTS 2,150,207 3/1939 Currie ..206/56 R 3,110,137 11/1963 Gross ..5l/380 Primary Examiner-Othell M, Simpson Attorney-Hugh E. Smith and Herbert I... Gatewood [57] ABSTRACT A flexible abrasive tool having a conical shape is provided with tear means whereby the tool can be separated, if desired, into two or more abrasive tools of the same conical shape but of lesser desired vertical height.

7 Claims, 3 Drawing Figures COATED ABRASIVE CONES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to coated abrasive tools employed in the polishing, cutting, and finishing of various materials.

2. Description of the Prior Art In many instances one finds it necessary to grind conical shaped openings or structures such as those found, particularly, in internal combustion engines. Over the years abrasive articles in the shape of a frustum or truncated cone have been found satisfactory for this purpose. One disadvantage, however, with the use of these abrasive articles is that, in general, a relatively large supply of various sizes must be kept on hand. This is so even where the surfaces being ground are of the same conical shape because the surfaces may not be of the same depth. Thus extra storage facilities must be provided by the user of such abrasive articles and it is necessary, in some cases, that large users maintain extra inventory records as well as extra records for ordering and reordering of the abrasive supplies.

SUMMARY OF THE INVENTION In accordance with my invention, a cone shaped abrasive article is provided with tear means whereby the article may, if desired, be separated by the user into two or more abrasive articles of the same conical shape but of a lesser desired vertical height.

With my invention the disadvantages above pointed out may be avoided. Moreover, most advantageously, the manufacturer of such an abrasive article can manufacture, at one time, a conical shaped abrasive tool which is suitable for more than one grinding application. Two or more sizes of a coneshaped abrasive tool can thus be provided in one relatively simple, easy, operation requiring no additional processing steps over that presently existing in the manufacturing operation.

BRIEF DESCRIPTION OF THE DRAWING The invention will be better understood by referring to the drawing, as one reads the specification, in which like numerals refer to like parts in the various views, and in which:

FIG. 1 is a top plan view of an arcuate section of coated abrasive material which is to be formed into a coated abrasive frustum or truncated cone;

FIG. 2 is a view in perspective of a coated abrasive frustum; and

FIG. 3 is a view in perspective showing the frustum in FIG. 2 being separated into two frustums of lesser vertical height.

DETAILED DESCRIPTION OF THE DRAWING AND PREFERRED EMBODIMENT Turning now to the drawing, there is disclosed in FIG. 1 thereof coated abrasive material which has been cut, in a known manner, from sheet material or the like, not shown, to provide an arcuate shape. The arcuate shaped coated abrasive material, as shown, has two curved edges ll, 12 connected together by means of

straight edges

13, 14. A curved line offering less tear resistance than the abrasive material per se is provided, in accordance with my invention, at some desired location between and parallel with the curved edges.

As seen from examining the drawing,

straight edges

13, 14 are inclined at an angle inwardly toward one another, curved edge 1 1 being of somewhat lesser length than curved edge 12.

The length of the curved edges and their degree of curvature, as well as the angle of taper of the straight lines will depend, of course, upon the particular application for the coneshaped abrasive article, as well as the arbor or drive member therefor. Merely by way of example, the arcuate shaped coated abrasive material 10 shown in FIG. 1 may be die cut from a larger abrasive sheet so that a

straight edge

13, 14 of 4.03 inches is provided while at the same time providing curved edges 11, 12 having radii of curvature of 8% inches and 12 1 1/16 inches, respectively.

In preparation to forming the truncated cone abrasive tool 16, shown in FIG. 2, a rectangular area 17 is skived, according to usual techniques, to remove the abrasive grain and adhesive bond. A suitable adhesive composition, for example, a polyurethane, is then applied to the skived surface, which may extend, for example, about one-fourth inch from the edge, and

ends

13, 14 are overlapped and joined together in formation of abrasive tool 16 in a manner well known to those skilled in the coated abrasive art. Thus, on completion of joining straight edges l3, 14 together, a hollow, flexible conically shaped abrasive tool 16 is provided having a flat, cut-off top or upper end 18 and a bottom 19. Abrasive grain 20 is indicated in the drawing to be on the outside of the conical shaped abrasive tool; however, in some instances it may be desirable to form the abrasive tool so that the grain is on the inner surface of the hollow tool.

In some instances to provide better adhesion, it may be desirable to back rub or abrade the back surface of edge 14 in an area complementary to the skived area. This is conventionally done in the splicing of coated abrasive material to remove back surface treatment materials and, it is believed, requires no further explanation herein.

Alternatively, it may be desirable at times to join the straight edges together by means of a butt splice rather than by overlapping. This method of joining is also practiced conventionally in the coated abrasive industry.

Tear line 15 is provided in the same operation in which the arcuate section is die-cut from a larger sheet of coated abrasive material. As seen from the drawing, in the preferred embodiment, tear line 15 is defined by slits 21 cut in the abrasive material which alternate with portions 22 of abrasive material which have not been cut. The manner of making such a tear line is deemed well known and cutting means can be provided on the same die as that used for cutting out the arcuate section. In this way both cutting operations can be accomplished simultaneously.

Slits 21 can be from about one-eighth inch to about threeeighth inch in length and preferably extend only about threesixteenth one-fourth inch in length. The portion 22 of coated abrasive material between each adjacent slit 21 should be about three-sixteenth inches in length. These dimensions, it will be found, will result in a tear line providing satisfactory separation, should that be desired by the user, yet preclude inadvertent or undesired separation in use or during handling and storage.

As is believed obvious, more than one tear line can be provided in the arcuate section thus making it possible to provide, in one operation, a multiplicity of conical shaped abrasive articles of the same angle but of lesser vertical height.

Although not absolutely critical, it is highly desirable that slits 21 be provided, as shown in FIG. 1, at and extending inwardly from each

edge

13, 14. Thus, when an overlapped joint is formed, as in the preferred embodiment of my invention, tearing will not be rendered unduly difficult, if not nearly impossible, to perform.

In the practice of my invention, one selects an abrasive tool from inventory having the general configuration shown in FIG. 2. The tool can be used as is, on a suitable mandrel, where the grinding application can accommodate its vertical height. However, most advantageously, where a tool of lesser height is needed, the abrasive tool can be separated, as shown in FIG. 3, at the appropriate pre-determined tear line to satisfy these requirements. The location of the tear line and the resulting vertical height of the conical abrasive tools formed in the separation are, of course, pre-determined by the various applications to which the abrasive tool will be put. Although, in FIG. 3, abrasive tool 16 is shown separated into only two tools 16' and 16" of lesser vertical height, tool 16 can be separated into a greater multiple of abrasive tools, as beforementioned, where this is desired.

Having now fully disclosed my invention, it is to be understood that the scope of the invention is intended to be limited only by the disclosure as a whole, including the appended claims.

I claim:

1. An abrasive tool having the shape of a hollow truncated cone, said cone comprising an arcuate shaped flexible abrasive material defined by first and second spaced apart curved edges of different lengths connected together by spaced apart straight edges, said straight edges being joined together along their length whereby said first and second curved edges define a truncated cone having a top and a bottom, and at least one tear line located between said top and bottom and parallel therewith and extending around the entire periphery of the cone shaped article.

2. An abrasive tool in accordance with claim 1 in which said tear line comprises slits in the abrasive material alternating with portions of the abrasive material which are not slit.

3. An abrasive tool in accordance with claim 2 in which said slits are from about three-sixteenth inches to about one-fourth inch in length.

4. An abrasive tool in accordance with claim 3 in which said portions of abrasive material are each about one-sixteenth inch in length.

5. An abrasive tool in accordance with claim 1 in which said straight edges are so positioned that one edge overlaps the other.

6. An abrasive tool in accordance with claim 5 wherein each of the overlapped edges contain a slit extending inwardly therefrom and the slit in one edge is so located that it matches with the slit in the other edge thereby making for easier separation at the overlapped joint.

7. An abrasive tool in accordance with claim 6 in which the abrasive material has abrasive grain on its outer surface.

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