US2624986A - Abrasive disk - Google Patents

Description

Jan. 13, 195,3 v.v| LooFBoRo ETAL 2,624,985

ABRAsIvE DISK Filed'July 19, 195o 2 SHEETS-SHEET 1 EEZ . Erzi INVENTORS Vernon L. Loo'bora Robert @White @nl ZAM-J Al-s.

Jan. 13, 1953 v. L. LooFBoRo r-:rAL 2,624,986

ABRAsIvE msx Filed July 19, 195o 2 SHEETS- SHEET 2 INVENTORS e non L. Looftgor-o bert C1, M/hd'e BY/Za I Patented Jan. 13, 195,3

ABRASIVE DISK Vernon L. Loofboro, Rockton, Ill., and Robert A. y White, Beloit, Wis., assignors to Gardner Machine Company, South Beloit, ill., a corpora*- tion of Illinois Application July 19, 1950, Serial No; 174,722

11 Claims. 1,-

The present invention .pertains generally to grinding Wheels and more specifically to an improved reinforced abrasivedisk of the general type disclosed in United States Patents 1,964,537, 1,964,538, and 1,964,539, all 'issued June 26, 1934, to Ingle R. Shue. The-subject matter of the present application is closely related' to that contained in our copending. applications, Serial Nos. 174,723'and 174,724 led in theUnited States Patent Oice on July 19, 1950.

Abrasive disks of the type-under consideration here usually have a relatively small thickness in comparison to their diameter. To adapt them to high speed grinding operations, it is a common practice to reinforce such disks internally and mount them upon an appropriate rotary support or backing surface. Upon vmore particular reference to the foregoing patents. it will be noted that each of the disks thereshown is rein-forcedinternally as by means of a wire mesh or grid barely covered by the-abrasive material defining its rear or mounting face. The disk is secured against the supporting Wheel by screws which engagenuts disposed in engagement with theV face of the mesh remote from the mounting face of the disk.

While abrasive disks constructed in the above manner lhave been commercially satisfactory, they have :also been subject to a number of disadvantages. 'Ihus the vlocation of the reinforcing mesh in close' proximitywith the rear face of the disk detracts-from theA strength of the same and sometimes resultsy in-cracking-away Iof the abrasive from those points on the mesh nearesty the rear face of the disk. Such cracking away is particularly noticeable in theregions of the attaching nuts since the clamping pressure exerted by the latterl sets up a crushing action upon the underlyingv abrasive. Moreover, in disks which operate at high. rotational speeds, it is desirable to^locate the internal reinforcement as close as possible to: the itransverse'medial plane of the disk so as to set upa maximum resistance to `centrifugal force. ItJisf-With the elimination of the foregoing disadvantages that the present invention is concerned.

One object lof the invention is to pr-ovide an abrasive disk of the `character-set forth and which will have greater Vstrength and a'higher safety factor than any such disks-heretofore produced.

Another object isto provide an` abrasive disk of the above type havingfarlimproved mounting means together with a novelcorrelation between such means.A and the finternal reinforcing mesh of the disk,..such correlation:-,contributing :sube

stantially to the increased strength of the disk. A further o'bject is to provide an abrasive disk of the foregoing type and comprising a reinforcing mesh together with Imounting members susceptible of assembly into an integral self-contained structure which can be moved about bodily during manufacture of the disk.

Still another object is to provide a disk of th foregoing character and'Which Will be susceptible of economical manufactureon a mass production basis.

Other objects and advantages will become apparent as the following description proceeds, taken in connection with the accompanying drawings,` wherein:

Figure 1 is a face view of the mounting surface of an illustrative disk embodying the present 'invention, a portion of the abrasive material having been cut aW-ayto illustrate more fullythe internal reinforcement of the disk.

Fig. 2 is a side vieW'of the'abrasive disk shown in Fig. 1, `such disk being mounted in place lupon a rotatable supporting wheel.

Fig. 3 is an enlargedv fragmentary transverse sectional view throughy the villustrative abrasive disk' and its supporting Wheel, such 'view being taken in the planeof the line 3"-3'in Fig. 1.

Fig. 4 is la plan view of certain parts of the disk illustrated in Fig.y 3,V the 'abrasive having' been omitted to permit clearer-illustration of thev internal members Vof `the disk."

Figs. 5 -and 6 `are enlarged fragmentary views corresponding respectively to Figs. 3 and 4 but de'- tailing a modified form `of abrasive disk also ernL bodying the invention.

Figs. 7 and 8 are enlarged Vfragmentary views also correspondingrespectively'to Figs.V 3 an`di4' but detailing still another' modification falling within the scope'of the-present invention.

Figs. 9-and lOare enlarged fragmentary sectional views similar to Fig. 3 but illustrating two' Referring moreV specifically to" 'the drawing; there' '1s .showniin Figs.` l and i2" an illustrative abrasive disk 26 embodying the present invention and susceptible of attachment to a rotatable supporting wheel 2|. In the present instance. the disk is of flat annular shape, being formed with a central recess 22 together with a grinding face' 24 and a mounting face 25 which abuts against face 26 of the supporting wheel. Substantially coextensive with the disk 20 and imbedded in the body 28 thereof is a metallic reinforcing mesh 29 which happens in the present instance to be a wire grid. operatively associated with the mesh 29 and partially imbedded in the body 28 of the disk are a plurality of fastening members 30 by means of which the disk may be attached to the supporting wheel 2| Means is provided for effecting a direct mechanical connection between the abrasive disk 20 and the supporting wheel 2| without danger of subjecting the abrasive material to crushing or shear stresses normal to the plane of the disk.

This is accomplished by forming the fastening members 30 as non-deflectable compression members each terminating in a laterally enlarged stationary bearing surface 3| coplanar with the mounting face of the disk. Since the fastening members are identical with each other, a description of one will suffice for all. Referring in particular to Figs. 3 and 4, it will be perceived that the fastening member 30 there shown has an intermediate section of reduced diameter and is adapted for insertion through a corresponding one of the interstices of the mesh 29. In addition, the member 30 has a pair of lateral enlargements spaced apart by such intermediate section and which snugly sandwich the underlying marginal portion of the mesh therebetween. By reason of this arrangement the member 30 is rigidly secured to the mesh 29 with its bearing surfaces 3| coplanar with the mounting face 25 of the disk and disposed in axially spaced relation to the plane of the mesh 29.

In the present instance, the member 30 comprises a nut 32 adapted to threadedly receive the end portion of cap screw 34 projecting axially of the supporting wheel 2|. The screw 34 runs from a, counterb'ore 35 in the rear face of the supporting wheel 2| and extends through the front face 26 of the wheel 2| as well as through the mounting face 25 of the abrasive disk 20. The intermediate section of the member 3D is defined by a shank 33 of appropriate size to fit through one of the interstices of the reinforcing mesh 29. The end of the shank 33 projecting toward the grinding face 24 of the disk is adapted for snug engagement with a lateral enlargement such as snap-on spring washer 36. The latter is of suitable diameter to overlie and abuttingly engage a marginal portion of the mesh 29 surrounding the shank 33. To facilitate engagement with the washer 36 and to better preclude disengagement of the same, the shank 33 may optionally be provided with a shallow peripheral groove 38. The end of the shank 33 adjacent the mounting face 25 of the disk terminates in a second lateral enlargement in the form of an integral head 39 preferably of hexagonal or some other non-circular geometrical shape. The laterally enlarged head 39 underlies and abuttingly engages a marginal portion of the reinforcing mesh surrounding the shank 33, such portion of the mesh being tightly sandwiched between the head 39 and the washer 36. As clearly indicated in the drawing, the head 39 terminates in the large and substantially annular stationary 4 bearing surface 3| coplanar with mounting face 25 of the disk.

By reason of the construction just described, it will be noted that axial play of the fastening member 30 relative to the reinforcing mesh 29 or to the disk body 28 is completely eliminated. Consequently, when the cap screw 34 is tightened to secure the disk 29 in abutment with the supporting wheel 2|, the resulting clamping pressure is transmitted by metal-to-metal contact over a wide annular area coextensive with the bearing surface 3|. The clamping stress applied to the disk 20 is taken up simply as compression within the nut 32 itself. Due to this fact, and also the fact that the comparatively large annular bearing area 3| minimizes the unit pressure on the metal-to-metal contacting surfaces between the nut 32 and the wheel 2|, the outer face of the nut head 39 will not be forced out of coplanar relation with the mounting face of the disk by penetration into the face 26 of the supporting wheel. Consequently, there is no danger of subjecting the abrasive material to crushing or shear stresses in a direction normal to the plane of the disk 2D. A certain amount of stress in the plane of the disk 20 may be transmitted to the abrasive body 28 but the latter is well able to withstand such stress if present. In any event, stress in this direction is offset somewhat by the frictional contact between the lateral enlargements of the member 30 and the mesh itself, as well as frictional contact between the bearing surface 3| and the base' 26 of the supporting wheel. To avoid undesirable concentrations of stress at the ends of the cap screws 34, the body 28 of the disk is preferably fashioned with a slight clearance recess 40 adjacent the projecting end of the shank 32.

In order to recess the reinforcing mesh 29 well within the body 28 of the disk and as close as possible to the medial plane of the same, advantage is taken of the laterally enlarged nut head 39, its thickness in a, direction normal to. the plane of the disk defining the space between the mounting face 250i the disk and the plane: Thus all portions of the mesh.

of the mesh 29. 29 are located well within the body 28 of the disk and the possibility of exposure of the mesh due to chipping or breaking away of very thin areas of abrasive is effectively precluded.

Turning now to Figs. 5 and 6, there is fragmentarily shown a modified embodiment of the invention in the form of a disk 20A having a plurality of modified fastening members 30A such as the one illustrated in the drawing. In view of the close similarity between the disk 20A and the disk 20, like parts will be designated by the reference characters used earlier herein. In the present instance, the member 30A comprises a nut 44 having a threaded shank 45 which projects through an interstice of the mesh 29 to engage a lateral enlargement in the form of a coacting nut 46. The nut 46 is adapted to abuttingly engage the underlying marginal portion of the mesh 29 surrounding the interstice and to sandwich such portion snugly against a second lateral enlargement in the form of head 39 of the nut 44. The outer face of the head 39 is spaced axially from the plane of the mesh 29 and defines a laterally enlarged substantially annular bearing area 3| ooplanar with the mounting face 25. After the nut 46 is tightened securely against the head 39 during the manufacture of the disk 20A, the abrasive materialof the body 28 is forced therearound to preclude unscrewing of the.

aczgeee,

nut et and to permanently. nx the head39 with bearing surface 3l coplanar with thedisk mounting face 25. Thus upontightening of cap screw ttl, no crushing or shear stresses are applied to the abrasive in a direction normal to the plane of the disk 29A. Any reaction to the tendency of the member 30A to turn in the plane of the disk as the screw 3,4 is tightened can be easily withstood by the abrasive body 28. As in the case of the fastening member 30, the head 39 of the member 30A is of suflicientv thickness to imbed the mesh 29 well within the body 28 of the abrasive so as to increase its` resistance tov centrifugal stresses and also to preclude surface cracking.

Figs. 7 and 8 disclose fragmentarily still another disk B having modied fastening members 39B embodying. the invention. Inthis instance, each member B comprises a, nut 4,9 generally similar to the nuts 33, but which isY secured to the mesh 29 in a, somewhat different manner. Accordingly, the nut 49 has xed to the projecting end portion o f its shank a spring washer 59 which engages the underlying face of the mesh 29, pressing the same against laterally enlarged head 39 of the nut. To hold the washer 59 in place, the end ofthe shank is upset as at 5l, such upset portion engaging land partially overlying radial prongs 52 of the washer. When secured in place by the means just described, the fastening member 30B behaves in a manner substantially identical with that of themembers 30, 39A described earlier herein.

Figs. 9 Yand 10 disclose fragmentarily additional modifications of the invention in the form of illustrative disks 20C, 26D having fastening members 30C, 30D respectively. In the disk 20C, the fastening member 39C comprises a nut 55 similar to those described above but having fixed to its upper end a relatively heavy dished washer 56. The latter is sweated or press it to the shank 58 of the nut 55 so as to clamp the surrounding margins of the mesh 29 against laterally enlarged head 39 of the nut. Clamping of the disk 29C to the supporting wheel 2| may be eiected as by means of the cap screw 34 in the manner described earlier herein.

Modied fastening member 30D of the disk 20D (Fig. 10) (,:omprisesaV nut 60. having an upstanding shank 67| terminating in a lateral en.

largement at the end adiacentvthe grinding face 24 of the disk. As the drawing indicates, the end portion 62 of the nut is integral with the same and of frusto-conical shape, tapering toward the face 2d. In the construction of the disk 26D, the nut 60 may be forced through one of the interstices of the mesh 29 due to the taper of the end portion 62, thev mesh springing back into its original shape after the nut is positioned therein. By proper proportioning of the parts, the nut 6G may be mounted so that it clampingly engages the surrounding portion of the mesh 29 between the flared skirt of thelateral enlargement 62 and the laterally enlarged head 3 9 oi the nut. The frictional effect between the nut and the mesh 29, together with the. forceset up by the abrasive body 2 8V in the plane of therdisk, serve to secure the nut 6i) against turning upon tightening of the cap screw` 34. The outer faceof the head 39 denes a laterally enlarged stationary bearing surface. 3i coplanar with the mounting face 25 of the disk and precludes the setting up of clamping or crushing stressesv in the abrasive normal to the plane of the disk in the manner described earlier herein.

Upon reflection, itv will `be appreciated. that there has been provided ak plurality ofdisk con; structions adequately meeting thelobiectives set forth above. In addi-tion to improving the con.

sheet metal stamplgs which lend themselves,

readily to mass productive operations. Although such fastening members,` are well'adapted to` be fixed to the reinforcing. mesh to. denne endete` gral, self-contained structure capable of being moved bodily asan incidentto manufactured a disk, it might be observed thatY they are .alsostls-- ceptible of beine assembledl in the meldior the. disk.

We claim as our inventienr 1. A, remicreed abrasive disk.A adapted ier' mounting `upon a rotatable, supporting wheel and: comprising, in combinatiom areinforcingmeshp a body of abrasive material molded about said mesh and having a grinding face` and a mounting face, said mesh being recessed well withinsaid body between said grinding and said mount-- ing faces, fastener members imbedded Within said body and each having spaced apart lateralI enlargements sandwichingV said mesh therebetween as well as a reduced intermediate portion passing through` the mesh, said membersA` beingv disposed in radially` and circumferentially spacedrelation with respect to each other, one of saidlateral enlargements of each fastenermember` having an area larger than the cross-sectional` fastener memberhaving an intermediate portion.

terminating in a pair of axially spaced laterally enlarged portions clampingly secured in engage-V ment with bothfaces oi'said mesh, said fastener membervbeingY imbedded in said body with one of said` laterally enlarged portionsterminating in a relatively large stationary bearingI face "coplanar with the` mounting face of the abrasive disk, said stationary bearing face being vsubstannelly larger in area thenthe, croserseeteneleree.

of Seid intermediate portion. 0i Seri fastener engagementwith the oppositeface of said mesh.. oneof said lateral .enlargements terminating inv a relatively large stationary bearingiface axiallylv spaced from the plane of said mesh and coplanar with the mounting face of said disk. said stationary bearing face being larger than the crosssectional area of said shank.

4. In a reinforced abrasive disk adapted for mounting upon a rotatable supporting Wheel, the combination comprising a wire reinforcing mesh, a body of abrasive material molded about said mesh and having a mounting face, a fastener nut imbedded within said body and having a rst lateral enlargement of non-circular cross section together with a shank disposed in projecting relation through one of the interstices of said mesh, and a second lateral enlargement fixed to said shank adjacent the end remote from said first lateral enlargement and adapted to sandwich a marginal portion of said mesh thereagainst, one of said lateral enlargements having an outer face defining a relatively large stationary bearing area coplanar with the mounting face of said body, said stationary bearing area being larger than the cross-sectional area of said shank.

5. In a reinforced abrasive disk adapted for mounting upon a rotatable supporting Wheel, the combination comprising a Wire reinforcing mesh, a body of abrasive material molded about said mesh and having a grinding face and a mounting face, said mest being embedded within said body and spaced apart from said grinding and said mounting faces, a fastener nut imbedded within said body and having a laterally enlarged. head of non-circular cross section together with a shank disposed in projecting relation through one of the interstices of said mesh, said head having an outer face defining a relatively large stationary bearing area coplanar with the mounting face of said body and larger than the cross-sectional area of said shank, and a lateral enlargement xed to said shank adjacent the end thereof remote from said head, said lateral enlargement being adapted to sandwich the underlying marginal portion of said mesh against said head.

6. A reinforced abrasive disk susceptible of detachable connection to a rotatable supporting wheel and comprising, in combination, a reinforcing mesh, a body of abrasive molded about said mesh, said body having a grinding face and a mounting face spaced axially from said grinding face, a plurality of mounting nuts imbedded within said body and each having a shank portion projecting through one of the interstices of said mesh, a spring washer lockingly mounted on each said shank in clamping relation with one face of said mesh, a laterally enlarged head integral with the opposite end of each said shank and disposed in clamping engagement with the opposite face of said mesh, said enlarged head terminating in a metallic bearing face axially spaced from the plane of said mesh and coplanar with the mounting face of said disk, said bearing face being substantially larger in area than the crosssectional area of said shank to present a substantial metallic bearing at the mounting face and prevent transfer of clamping stress to said abrasive body.

7. In a reinforced abrasive disk susceptible of mounting upon a rotatable supporting wheel, the combination comprising a wire reinforcing mesh, a body of abrasive material molded about said mesh and having a mounting face thereon, a mounting nut imbedded within said body and having a shank projecting through one of the interstices of said mesh, said shank having a perinheral groove adjacent its projecting end, a

spring washer mounted on said shank and disposed in locking engagement with the peripheral groove, said spring washer being adapted to clampingly engage one face of said mesh, a laterally enlarged head of polygonal cross section integral with the opposite end of said shank and disposed in clamping engagement with the opposite face of said mesh, said enlarged head having an outer face coplanar with the mounting face of said disk and of substantially larger size than the cross-sectional area of said shank.

8. In a reinforced abrasive disk of the type carried upon a rotatable supporting wheel, the combination comprising a reinforcing mesh, a body of abrasive material molded about said mesh and having a mounting face thereon, a mounting nut imbedded within said body and having an externally threaded shank projecting through one of the interstices of said mesh, a clamping nut disposed in threaded engagement with the projecting end of said shank and in clamping abutment with the marginal portion of said mesh surrounding the interstice, a laterally enlarged head integral with the opposite end of said shank and also disposed in clamping abutment with the surrounding marginal portion of said mesh, said enlarged head terminating in a stationary bearing surface coplanar with the mounting face of said disk, said stationary bearing surface being substantially larger than the cross-sectional area of said shank.

9. In a reinforced abrasive disk adapted for mounting upon a rotatable supporting wheel, the combination comprising a reinforcing mesh, a body of abrasive material molded about said mesh and having a mounting face thereon, a mounting nut imbedded Within said body and having a shank projecting through one of the interstices of said mesh, the projecting end of said shank being upset laterally, a spring Washer snapped over the upset end of said shank and into clamping abutment with the marginal portion of said mesh surrounding the interstice, a laterally enlarged head integral with the opposite end of said shank and also disposed in clamping abutment with the surrounding marginal portion of said mesh, said enlarged head terminating in a metallie stationary bearing surface coplanar with the mounting face of said disk, said stationary bearing surface being substantially larger in area than the cross-sectional area of said shank to prevent the transfer of clamping stress to said abrasive body.

l0. A reinforced abrasive disk mountable upon a rotatable supporting wheel and comprising, in combination, a reinforcing mesh, a body of abrasive molded about said mesh, said body having a grinding face and a mounting face spaced axially from said grinding face, a plurality of mounting nuts imbedded within said body and each having a shank portion projecting through one of the interstices of said mesh, a dished washer f oreed into rigid attachment with the projecting end of each said shank and also into clamping engagement with one face of said mesh, a laterally enlarged head integral with the opposite end of each said shank and disposed in clamping engagement with the opposite face of said mesh, said enlarged head terminating in a stationary bearing face axially spaced from the plane of said mesh and coplanar with the mounting face of said disk, said stationary bearing face being substantially larger in area than the crosssectional area of said shank.

11. In a reinforced abrasive disk susceptible of 9 mounting upon a rotatable supporting Wheel, the combination comprising a wire reinforcing mesh, a body of abrasive molded about said mesh, said body having a grinding face and a mounting face, a plurality of mounting nuts imbedded Within said body and each having a shank projecting through one of the interstices of said mesh, a laterally enlarged tapered end portion integral with the projecting end of each said shank and disposed in clamping engagement with the marginal portion of said mesh surrounding the interstice, and a laterally enlarged head integral with each said nut and also disposed in clamping engagement with said marginal portion of said mesh, said head having an exposed face defining a stationary bearing area coplanar with the mounting face of said disk, said stationary bearing area being larger than the cross-sectional area of said shank.

VERNON L. LOOFBORO. ROBERT A. WHITE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,261,146 Marble Apr. 2, 1918 1,489,373 Tomkinson Apr. 8, 1924 1,711,453 Carr Apr. 30, 1929 1,742,052 Anderson Dee. 31, 1929 1,812,076 Beebe June 30, 1931 1,964,537 Shue June 26, 1934

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