US3292311A

US3292311A - Abrasive wheels

Info

Publication number: US3292311A
Application number: US404267A
Authority: US
Inventors: James J Hensley
Original assignee: Individual
Current assignee: Kennecott Corp
Priority date: 1961-12-06
Filing date: 1964-10-16
Publication date: 1966-12-20
Anticipated expiration: 1983-12-20

Description

Dec. 20, 1966 J. L. HENSLEY ABRASIVE WHEELS 2 Sheets$heet 1 Original Filed Dec. 6, 1961 INVENTOR JAMES 4 #506415 y ATTORNEY;

Dec. 20, 1966 HENSLEY 3,292,311

ABRASIVE WHEELS Original Filed Dec. 6, 1961 2 Sheets-Sheet 2 F [g 6 INVENTCR.

James L, #015 I0 ATTORNEYS United States Patent f 3,292,311 ABRASIVE WHEELS James J. Hensley, Clinton, Tenn. '(P.0. Box 1269, Knoxville, Tenn.) Original application Dec. 6, 1961, Ser. No. 157,514, now Patent No. 3,255,289, dated June 7, 1966. Divided and this application Oct. 16, 1964, Ser. No. 404,267 2 Claims. (Cl. 51-206) This application is a division of my prior application for Methods of Making Abrasive Wheels, Serial No. 157,514, filed December 6, 1961, now Patent No. 3,255,289.

This invention relates to improvements in abrasive wheels, particularly of the character used for cut-oft machines.

One method of manufacturing abrasive wheels involves the use of a circular type press. The desired quantity of abrasive material is formed into the mold and spread over the area thereof. This material usually is made of abrasive particles combined with a binder capable of being pressed and hardened to form a disc. Frequently, such a disc may be made up to thirty-four inches in diameter and seven thirty-seconds inch thick. A top mating pressure plate is used to press the material to the desired shape and density.

Thereafter, the wheel thus formed is removed from the press for curing. It must be kept flat until fully cured and ready for use. If laid without support over the entire area thereof, the wheel is subject to warping, taking a permanent set out of flatness, which would destroy its usefulness.

In the use of an abrasive wheel, especially of large diameter size, and in making deep cuts, the wheel is subject to many adverse operating stresses, such as excessive side binding which required increased power to continue the operation thereof. Moreover, cooling of the wheel becomes difficult in making deep cuts.

It has long been known that the wheel would be improved by making the rim section thicker than the web section inwardly of the rim, but no satisfactory way has been found heretofore of making the wheel with a thicker rim and maintaining it in condition for use. An attempt has been made to shape the press to form a uniform taper in the web section continuously from the peripheral edge of the rim to the center. This left a feather edge that was not sufiicient to prevent side travel. Moreover, it required a pallet having a supporting surface complementary to the surface of the wheel to support the latter to prevent distortion to one flat side during curing and continuously until put into substantial use.

One object of this invention is to overcome the objections to abrasive wheels with straight sides and to improve the method of making abrasive wheels.

Another object of the invention is to provide in the method of manufacturing an abrasive wheel with a thickened rim, of support means therefor Within the face of the Wheel and readily removable when the wheel is ready to be put to use.

Still another object of the invention is to provide for molding an abrasive wheel upon a separate core placed within the mold and of appreciably smaller area than the area of the mold and wheel and molded in the surface of the wheel to be removed from the mold therewith but capable of ready separation from the wheel when the latter is to be used.

These objects may be accomplished by placing one or more sheets of material in the bottom of the mold and of appreciably less area than the area of the mold, and also of appreciable composite thickness so as to form a Web section of less thickness than the thickness of the Patented Dec. 20, 1966 rim section. The material used in the mold can be of varying or any desired thickness according to the amount of stepped taper desired in the finished wheel. A like number. of sheets of material preferably are used under the pressure plate on top of the composition for a properly balanced wheel. These sheets would adhere to the formed wheel and remain thereon after removal from the mold and during curing, and, in fact, until the wheel is ready for use.

This method is illustrated in the accompanying drawings, in which:

FIG. 1 is a cross section through a mold showing layers of molding material to be applied to opposite sides of an abrasive wheel in the molding thereof;

FIG. 2 is a cross section through the molded wheel after removal from the mold;

FIG. 3 is a similar view of the wheel ready for use;

FIG. 4 is a cross section of the wheel in the work;

FIG. 5 is a plan view of a modified form of wheel;

FIG. 6 is a detail perspective view of the modified abrasive wheel made with molding sheets of material of the character illustrated in FIG. 5; and

FIG. 7 is a sectional view of the modified abrasive wheel in the work.

The relative sizes and dimensions of parts are exaggerated in the drawings for clearness of illustration.

The invention is illustrated in connection with a mold of conventional form for clarity of illustration. This mold comprises top and bottom platens 1 and 2 shaped to mold a mass of abrasive plastic material to form a wheel of the desired contour and size.

The bottom platen 2 is provided with a cylindrical cavity 3 having a bottom face 4 usually smooth and flat. The under surface 5 of the top platen 1 is also usually flat and smooth continuously throughout the area of the top platen 1.

The means for forming the center hole in the wheel is illustrated as a pin 6 rising from the bottom cavity face 4 and of a length to extend entirely through the mold cavity. Any suitable means may be used for the purpose.

In making a wheel according to this invention, the moldable abrasive material is placed in the mold cavity 3 of a quantity according to the size and thickness of the wheel to be made, after which the top platen 1 may be applied thereto to effect the molding operation in the usual way. Suitable pressure is applied to the top platen and held for a length of time suflicient to effect the molding operation. Lining sheets a and b are shown in FIG. 1 extending over and throughout the respective areas of the surfaces 4 and 5 to facilitate separation of the molded wheel thereform. These lining sheets may be used if desired, but are not required according to this invention.

The abrasive wheel is illustrated in FIGS. 2 to 4, made with a thick rim section R and a relatively thinner web section W. This relatively thinner web section W is formed by one or more molding sheets on either or both sides of the mold cavity. In the example illustrated, such molding sheets are shown at c, d and e stacked fiatwise on the bottom face 4 of the cavity 3, and also three such molding sheets are shown at f, g and h stacked against the bottom face 5 of the top platen or the lining sheet b, if used.

Each of the molding sheets 0 to h extends symmetrically of the mold cavity but has its periphery spaced inwardly an appreciable distance from the periphery of the cavity. The largest diameter sheet or sheets thereof are in the inner periphery of the rim R. Where several sheets are used in each stack these form shoulders S on the face or faces of the wheel in one or more steps between the rim R and the web W of the wheel.

The molding sheets ch may be held in place in any suitable manner in the mold cavity and on the ,undersurface of the top platen 1. The sheet or sheets in the bottom of the cavity may be provided with central openings to fit around and on the central pin 6. In like manner, the sheet or sheets that are secured to the undersurface of the top platen 1 may be held in place around the opening in the bottom face of that platen in which the pin 6 is received when the platen is inserted in the cavity. Suitable means should be provided on the top platen to hold the sheets thereto, but to allow ready separation therefrom when the top platen is removed from the mold.

The molding sheets c-h may be formed of any suitable material found desirable for the purpose, such, for example, as Kraft paper, wax paper, or aluminum foil. The material should be such as would enable the sheet or sheets to be peeled readily from the formed abrasive disc or wheel when the latter is to be put into service. The molding sheet, if one is used on each surface, or the composite sheets if more than one are used on each surface, should heof suificient thickness so as to separate the web section W from the rim section R and to provide a definitely thicker rim section than the web section, as somewhat exaggerated in FIGS. 3 and 4. The greater thickness, nevertheless, of the rim section should be such as will provide a radial addition to the rim of uniform thickness so as to provide definite support for the wheel in the kerf formed in the material to prevent side travel of the wheel in operation. At the same time, the spacing of the web portion from the sides of the formed kerf permits free access of the cooling liquid to the rim and substantially throughout the area of the wheel to obtain maximum cooling effect.

After molding the wheel with the molding sheets embedded therein, the Wheel is removed from the mold and cured in the usual manner. The molding sheets remain in place on the wheel until the latter is ready for use. Then they may be peeled ofi? or separated, so as to provide for the operation of the wheel in the usual manner. When in place on the wheel, the molding sheets provide uniform support for the wheel, both during curing and during handling or storage.

Usually, these molded abrasive wheels are supported flat and they require support continuously throughout the area of each to prevent the possibility of distortional warpage. By molding the sheets directly in the surface of each wheel, the sheets remain in the wheel embedded therein and support the surface uniformly throughout.

Moreover, the provision of molding sheets in the center A portion of the wheel, spaced inwardly from the surrounding rim section, provides for greater pressure being applied to this center section, which will compact the moldable abrasive material with greater density than in the rim section. Thus, the wheel will harden more effectively in the center and produce a more durable wheel than one of uniform density throughout.

It is also possible to use molding sheets to modify the surface of the abrasive wheel in other respects than has been illustrated in FIGS. 1 to 4. One such sheet'would be used in the bottom of the cavity and another preferably in the top thereof under the top platen. When the abrasive material is thus deposited in the cavity between the sheets, a wheel would be molded in the usual manner, as indicated at W in FIG. 6. Such a wheel would have alternate ribs and grooves extending radially thereof on one or both opposite faces of the wheel, which would have excellent cutting and cooling eflFect and would minimize side binding during the operation of the wheel, as will be apparent from FIG. 7.

The alternate grooves and ribs will provide courses W2 for the cooling liquid to flow radially outward along the wheel entirely to the periphery thereof from the center portion W3 thereof during the operationof the cutting of metal, stone or other materials. In other respects the method of use and of manufacture illustrated in FIGS. 5 to 7 would be the same as set forth above and involve the use of similar materials.

While the invention has been illustrated and described in certain embodiments, it is recognized that variations and changes may be made therein without departing from the invention set forth in the claims.

I claim:

1. An abrasive wheel comprising a plastic body having abrasive particles embedded therein, said body having a thicker peripheral portion and a relatively thinner inter- 1 mediate web portion forming recesses at opposite sides of the body each having stepped portions progressively decreasing in area from the outer to the inner sides thereof, a plurality of sheets of material extending throughout the respective recesses and with the sheets respectively decreasing in area from the outer to the inner sides of the respective recesses, and means for attaching the sheets to the web portion for handling and for peeling of the sheets therefrom when the wheel is to be put into service.

2. An abrasive wheel comprising a plastic body having abrasive particles embedded therein, said body having a thicker peripheral portion and a relatively thinner intermediate web portion forrning recesses at opposite sides of the body, a plurality of sheets of material extending throughout the respective recesses and with the outer faces of the plurality of sheets co-planar with the outer. faces of the thicker peripheral portion, and means for attaching the sheets to the web portion for handling and for peeling of the sheets therefrom when the wheel is to be put into service. I

References Cited by the Examiner UNITED STATES PATENTS 2,259,554 10/1941 Clark 51-168 FOREIGN PATENTS 194,274 1/1958' Austria. ROBERT C. RIORDON, Primary Examiner.

L. S. SELMAN, Assistant Examiner.

Claims

2. AN ABRASIVE WHEEL COMPRISING A PLASTIC BODY HAVING ABRASIVE PARTICLES EMBEDDED THEREIN, SAID BODY HAVING A THICKER PERIPHERAL PORTION AND A RELATIVELY THINNER INTERMEDIATE WEB PORTION FORMING RECESSES AT OPPOSITE SIDES OF THE BODY, A PLURALITY OF SHEETS OF MATERIAL EXTENDING THROUGHOUT THE RESPECTIVE RECESSES AND WITH THE OUTER FACES OF THE PLURALITY OF SHEETS CO-PLANAR WITH THE OUTER FACES OF THE THICKER PERIPHERAL PORTION, AND MEANS FOR ATTACHING THE SHEETS TO THE WEB PORTION FOR HANDLING AND FOR PEELING OF THE SHEETS THEREFROM WHEN THE WHEEL IS TO BE PUT INTO SERVICE.