US2624987A - Abrasive disk - Google Patents

Description

Jan. 13, 1953. v. LooFaoRo ETAL ABRASIVE DISK Filed Juiy 19, 1950 2 SHEETSSHEET 1 Z9 55-8 f v H51 III INVENTORS Vernon L. Loofboro BY Robert a, White M v M 3 39 Jan. 13, 1953 v. L. LOOFBORO ETAL 2,624,987

ABRASIVE oxsx Filed July 19, 1950 2 SHEETS-SHEET 2 Z9 INVENTORS Vernon 1., Loofboro Robert a. White dww Patented Jan. 13, 1953 UNITED STATES PATENT orrlce White, Beioit, Wis, assignors toGardner Machine Company, South Beloit, 111., a corporation or Illinois Application July '19, 1950, Serial No. 174. 723

8 Claims. 1

The present invention pertains generally to grinding wheels and more specifically to an improved reinforced abrasive disk of the general type disclosed United States Patents 1,964,537, 1,964,538, and 1,964,539, all issued June 26, 1934 to Ingle R. Shoe. The subject matter of the present application is closely related to that contained in our copending applications, Serial Nos. 174,722 and 174,724, filed in the United States Patent Office on July 19, 1950.

Abrasive disks of thetype 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 more particular reference to the foregoing patents, it will be noted that each of the disks there shown is reinforced internally 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 engage nuts disposed in engagement with the face of the mesh remote from the mounting face of the disk.

While abrasive disks constructed in the above manner have been commercially satisfactory, they have also been subject to a number of disadvantages. Thus the location of the reinforcing mesh in close proximity with the rear face of the disk detracts from the strength of the sameand sometimes results in cracking away of the abrasive from those points on the mesh nearest the rear face of the disk. Such cracking away is particularly noticeable in the regions of the attaching nuts since the clamping pressure exerted by the latter sets up a crushing action upon the underlying abrasive. Moreover, in disks which operate at high rotational speeds, it is desirable to locate the internal reinforcement as close as possible to the transverse medial plane of the disk so as to set up a maximum resistance to centrifugal force. It is with the elimination of the foregoing disadvantages that the present inventionis concerned.

One object of the invention is to provide an abrasive disk of the character set forth and which will have greater strength and a higher safety factor than any such disks heretofore produced.

Another object is to provide an abrasive disk of the above type having an improved mounting means which is susceptible of being correlated in a novel manner with the internal reinforcing mesh of the disk as an incident to molding of the latter.

A- further object is to provide a disk of the foregoing character and which will be susceptible of economical manufacture on a mass production basis.

Other objects and advantages will become 843- iii Jim

, 2 parent as the following description proceeds, tak en in connection with the accompanying drawing, 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 away to illustrate more fully the 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 upon a rotatable supporting wheel.

Fig. 3 is an enlarged fragmentary transverse sectional view through one form of abrasive disk embodying the invention and taken in a plane corresponding to that of the line 3-3 in Fig. 1.

Fig. 4 is a plan view detailing certain parts of the disk as illustrated in Fig. 3, the abrasivematerial being omitted simply for purposes of clearer illustration. 7

Figs. 5 and 6 are enlarged fragmentary views corresponding respectively to Figs. 3 and 4 but illustrating a modified embodiment of the invention.

Figs.- 7 and '8 are enlarged fragmentary views also corresponding to Figs. 3 and 4 and whichillustrate still another modification embodying the invention.

Figs. 9 and 10 are enlarged fragmentary views corresponding respectively to Figs. 3 and 4 but showing afurther modification also embodying the invention. 1 a g While the invention is susceptible of various modifications and alternative constructions, certain preferred embodiments have been shown in the drawings and will be described below inconsiderable detail. Itshould be understood, however, that there is no intention to limit the in: vention to the specific forms disclosed, but on the contrary, the intention is to cover all modifica tions and alternative constructions falling within the spirit and scope of the appended claims.

Referring more specifically to the drawing, there is shown in Figs. 1 and 2 an illustrative abrasive disk 20 embodying the present invention and susceptible of attachment to a rotatable supporting wheel 24. In the present instance, the disk 20 is "of flat annularshape, being formed with a central recess 2 2 together with a grinding face and a mounting face 25 which abuts against face 26 of the supportingwheel. Substantially coextensive with the disk 23 and imbedded in the body 28 thereof is a metallic reinforeingmesh ld which happens in the present instance to be a wire grid. Operatively associat; ed with the mesh 9 and partially imbedded in the body 21'} of the diskare a pluralityof fas: tening members 33b3, means of whichjthe disk may be attached to the supportingwheelf I r a, .M 5 m rtifi d r. .e ee ne it me h nic l. QQPQQQQKPfiFWBFiQ h abrasiv disk 20 and the supporting wheel 2| without danger of subjecting the abrasive material to crushing or shear streses 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. Thus each of the fastening members has an intermediate section of reduced diameter and adapted for insertion through a corresponding one of the interstices of the mesh 29. In addition, each of the members 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. Each of the members 30 is thereby rigidly secured to the mesh 29 with its bearing surface 3| coplanar with the mounting face 25 of the disk and disposed in axially spaced relation to the plane of the mesh 29. Accordingly, we have constructed a disk having a plurality of fastening members 30, an exemplary one of which is illustrated in Figs. 3 and 4. Since such members are identical, a description of one will suffice for all.

Referring to the drawing, it will be perceived (that the member 30 comprises a nut 32 which is susceptible of threaded engagement with cap screw 34. The latter extends from a counterbore 35 in the rear face of the supporting wheel 2|, projecting outwardly through the face 26 of the supporting wheel and extending through the mounting face 25 of the abrasive disk 20. At its upper end (as viewed in the drawing), the nut 32 is fashioned with a lateral enlargement in the form of a head 36 preferably of hexagonal or some other non-circular geometrical shape and which terminates in a shank 38 of reduced diameter. The shank 38 constitutes the intermediate portion of the member 30 and is of appropriate size to pass through one of the interstices of the mesh 29, the head 36 being adapted to engage the underlying marginal edge portion of the mesh surrounding the interstice through which the shank passes. Operatively associated with the nut 32 is a lateral enlargement adapted to coact with the laterally enlarged head 36. Such coacting enlargement comprises a collar 39 which may be either rigidly fixed to or abutted against the depending end portion of the nut shank 38. The collar 39 is of appropriate size to clampingly engage the overlying marginal portion of the mesh 29 surrounding the nut shank, sandwiching the mesh snugly betweeen itself and the head 36 of the nut. These parts are so proportioned that when arranged as above described, the outer face of the collar 39 lies coplanar with the mountface 25 of the disk and defines a relatively large annular stationary bearing surface 3| which abuts directly against the face 26 of the supporting wheel. In the present instance, the depending end face of the nut shank 38, which is fixed relative to the collar 39, also constitutes a. small portion of the bearing surface 3|.

In the foregoing construction, axial play between the nut 32, the collar 39 and the mesh 29 is completely eleminated. Due to this fact, and also to the coplanar relationship between the stationary bearing surface 3| and the mounting face 25 of the disk, the axial clamping stress resulting from tightening of the screw 34 is balanced by compression of the fastening member 30 over a wide area of contact against the face 26 of the supporting wheel without subjecting the abrasive surrounding the member 38 to crushing or shear stresses normal to the plane of the disk.

Provision is made for minimizing the stress applied to the abrasive body 28 of the disk in .a direction parallel to its plane. Accordingly, in the present instance, the collar 39 is fashioned with a pair of diametrically opposed upstanding lugs 40 which project through the mesh and terminate in end portions 4|. The latter are bent into overlying relation with the end face of the nut head 36, the lugs 48 lying snugly against the flats on the edge of the head 36. This arrangement provides a positive mechanical connection interlocking the nut 32, the collar 39 and the mesh 29. By reason of such connection. the tendency of the fastening member 30 to turn in response to tightening of the screw 34 is withstood to a substantial extent by the reinforcing mesh 29 and the friction between the bearing surface 3| and front face 26 of the supporting wheel. Thus the stress applied to the abrasive body 28 in a direction parallel to the plane of the disk is greatly minimized. Concentration of stress at the ends of the cap screws 34 and which might result in punching through the grinding face of the disk 24 are avoided by regulating the length of the cap screws 34 and also by mainv#taining an adequate clearance space 42 between the end of the screw 34 and the abrasive body 28 of the disk.

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 collar 39, its thickness defining the axial space between the plane of the reinforcing mesh 29 and the mounting face 25 of the disk. This further reinforces the disk against centrifugal stresses, avoiding the occurrence of thin areas of abrasive material near the mounting face and which might otherise chip away from the mesh.

Referring now to Figs. 5 and 6, there is shown a fragmentary portion of a modified disk 20A similar to the disk 20 but differing in the construction of the fastening means. As shown in the drawing, the disk is equipped with a plurality of fastening members 30A, a description of one sufiicing for all. In this instance, the fastening member 30A comprises a nut 32A generally similar to the nut 32 and adapted to engage a suitable fastening means such as cap screw 34 carried by the supporting wheel 2|. The nut 32A is provided with a lateral enlargement in the form of a head 36 terminating in a shank 38 of reduced diameter. The shank extends through one of the interstices of the reinforcing mesh 29 and engages a stationary bearing collar 45 disposed in surrounding relation with the depending end of the shank 33 (as viewed in Fig. 5) and constituting a coacting lateral enlargement for the nut head 36. The stationary bearing collar 45 may be rigidly secured to the shank 38 as by means of suitable threads or a press fit, or the end face of the shank 33 may be abutted against the collar 45. One face of the collar 45 is disposed in positive engagement with the marginal portion of the mesh surrounding the shank 38 of the nut, sandwiching such portion against the head 36 of the nut. The opposite face of the collar 45 is coplanar with the mounting face 25 of the disk and defines a relatively large annular bearing surface 3|. In the present instance, the depending end face of the nut shank 38 is included in the bearing surface 3|. By means of this construction, it will be appreciated that the cap screw 34 can be tightened securely to clamp the disk 20A to the supporting wheel 2| without subjecting the abrasive material of the disk to crushing or shear stresses in a direction normal to the plane thereof.

To minimize stresses in the plane of the disk resulting from tightening of the screw 34, the collar 45 is rigidly fixed to the reinforcing mesh '29 as by means of one or more tack welds 4B.

This provides a direct and positive mechanical connection between the member 30A and the mesh 29. While it is preferable to construct the member 30A as indicated in the drawing, such member could be made so that the end ofthe'nut shank 38 abutt'ed against the inner face of the collar 45 or otherwise loosely engaged the same. By proportioning parts so that the head of the nut 36 is held against the mesh 29 with considerable clamping pressure before the abrasive body of thedisk is cast therearound, the-resulting frictional engagement between the nut and the mesh 29, as well as between the nut and the collar 45, sets up a considerable resistance to turning of the member 30A as the screw 34 is tightened and thereby minimizes'the stress on the abrasive;

In Figs. '7 and 8, we have fragmentarily shown still another embodiment of the invention in the form of a disk 203 similar to the disk 20 but'provided with a somewhat different fastening member 35B. The latter comprises a nut 32B similar to the nut 32, being formed with a head 36 and a shank38. The nut 323 has operatively associated therewith a collar 50 which may be made in the form of a relatively heavy sheet metal stamping. The member 50 is of generally rectangular shape, being provided with a central aperture for receiving'the shank of the nut, the

of the collar 50 being coplanar with the mounting face 25 of the disk and defining a substantial portion of the laterally enlarged bearing surface 3|. In the region of each of its corners, the collar 50 is provided with upstanding lugs 5| which project through the reinforcing mesh .29. The lugs 5| haveoutturned end portions 52 overlying portions of themesh 29.

Referring finally to Figs. 9 and 10, a further modification embodying the invention is fragmentarily shownin the form of a disk 200 having fastening means such as the 'member30C. The latter includes a nut 32C similar to the'nut 32 but is provided with still another form of lateral enlargement in the form of a collar 55. Such collar is preferably fashioned as an oblong sheet metal stamping and is press fit to the shank of the nut 32C. The inner face of the collar 55 coacts with the head 58 of the nut 32C to clampingly engage the marginal portion of the mesh 29. The outer face of the collar 55 is coplanar with the mounting face 25 of the disk and constitutes a major portion of the laterally enlarged bearin surface 3|. A mechanical connection between the collar 55 and the reinforcing mesh 29 is provided in the form of a pair of diametrically opposed upturned prongs 55. These may be tapered toward their free ends so as to wedgingly project through a corresponding interstice in the mesh. Upon tightening of the cap screw 34, the fastening means 360 behaves in muchthe same manner as the means 35B described above.

ihe fastening members disclosed herein are simple and economical to manufacture, being susceptible of manufacture on a mass production basis by the use of screw machines and sheet metal stamping equipment. In addition to this, they are sufficiently versatile to permit the use of various manufacturing techniques in the production of abrasive disks of the type disclosed herein. For example, these fittings may be assembled in advance and fixed to the reinforcing mesh so as to form a self-contained structure prior to insertion into a mold, or, on the other hand, they may be maintained as separate "parts and assembled immediately prior to the abrasive molding operation.

We claim as our invention:

1. A reinforced abrasive disk susceptible of attachment to a rotatable supporting wheel and comprising, in combination, 'a reinforcing mesh,

a body of abrasive molded about said mesh argl having a mounting face thereon, said mesh being recessed well within said abrasive body. a plurality of fastener nuts each having "a shank projecting through one of the interstices of said mesh and terminating in a face coplanar with the mounting face of said abrasive body, each of said nuts having a laterally enlarged head disposed in clamping engagement with one face :of said mesh, and a collar rigidly attached to the end of each said shank remote from said head and disposed in clamping engagement with the opposite face of said mesh, each of said collars terminat ing in a laterally enlarged bearing face coplanar with the mounting face of said body.

'2. A reinforced abrasive disk adapted for mount-ing upon a rotatable supporting wheel and comprising the combination of a reinforcing mesh, a body of abrasive material molded about said mesh and having a mounting face thereon,

said mesh being recessed well within said abrasive body, a plurality of fastener nuts each having a shank projecting through one of the interstices of said mesh, each said nut being rigidly positioned relative to said mounting face for the transmission of clamping stress to the supporting wheel independently of said abrasive body each of said nuts having a laterally enlarged head of non-circular cross section disposed in clamping engagement with one face of saidmesh, a collar engaging the end of each said shank .remote from said head and disposed in clamping engagement with the opposite face of said mesh, each of said collars terminatin in a laterally enlarged bearing face coplanar with the mounting face of said body, andmeans connected with each of said collars for positively locking .both said collar and said nut against rotation relative to said mesh.

3. In a reinforced abrasive disk susceptible of attachment to a rotatable supporting wheel, the combination comprising a reinforcing mesh, a body of abrasive material molded about said mesh and having a grinding face and .a mounting face spaced axially from the latter, .said mesh being recessed Well within said abrasive body, a fastener nut having a shank of reduced diameter projecing through one of the interstices of said mesh, said nut and shank being rigidly positioned relative to said mounting face for the transmission of clamping stress to said wheel independently of said abrasive body, said nut also having 'a laterally enlarged head of non-circular cross section disposed in clamping engagement with the marginal portion of said mesh surrounding the interstice, a collar engaging the end of said shank remote from said head and disposed in coacting relation with' the latter to clamp thereagainst the marginal portion of said mesh surroundin the interstice, said collar defining a laterally enlarged stationary bearing surface coplanar with the mounting face of said body, and a positive mechanical connection interposed between said collar and said mesh for precluding relative rotation between said collar, said nut and said mesh.

4. In a reinforced abrasive disk susceptible of attachment to a rotatable supporting wheel, the combination comprising a reinforcing mesh, a body of abrasive material molded about said mesh and having a grinding face and a mounting face spaced axially from the latter, said mesh being recessed well within said abrasive body and spaced from said grinding and said mounting faces, a fastener nut having a shank of reduced diameter projecting through one of the interstices of said mesh and terminating in an end face coplanar with the mounting face of said body, said nut also having a laterally enlarged head of non-circular cross section abutting the marginal portion of said mesh surounding the interstice, a collar rigidly attached to the end of said shank remote from said head and disposed in coacting relation with the latter to clamp thereagainst the marginal portion of said mesh surrounding the interstice, said collar and the adjacent end of said shank defining a laterally enlarged stationary bearing surface coplanar with the mounting face of said body, and a plurality of upstanding lugs fixed to said collar and disposed in interlocking relation with said mesh for precluding relative rotation between said collar, said nut and said mesh.

5. In a reinforced abrasive disk of the type adapted for attachment to a rotatable supporting wheel, the combination comprising a reinforcing mesh, a body of abrasive material molded about said mesh and having a grinding face and a mounting face spaced axially from the latter, said mesh being recessed well within said body, a fastener nut having a shank of reduced diameter projecting through one of the interstices of said mesh, said nut and shank being rigidly positioned relative to said mounting face for the transmission of clamping stress to said wheel independently of said abrasive body, said nut also having a laterally enlarged head of poly- .gonal cross section disposed in clamping engagement with the marginal portion of said mesh surrounding the interstice, a collar disposed in surrounding relation with the end of said shank remote from said head and in coacting relation with the latter to clamp thereagainst the marginal portion of said mesh surrounding the interstice, said collar defining a laterally enlarged stationary bearing surface coplanar with the mounting face of said body, and a plurality of upstanding lugs fixed to said collar and projecting through said mesh, said lugs being spaced in closely nested relation with the sides of said area, a fastening nut having a shank of reduced diameter engagin said annular collar, said nut and said shank being rigidly positioned relative to said mounting face for the transmission of clamping stress to the support independently of said abrasive body, said shank projecting axially from said collar through one of the interstices of said mesh, a laterally enlarged head integral with the end of said shank remote from said collar and adapted to sandwich thereagainst the marginal portion of said mesh surrounding said interstice. I H i -7.'In a reinforced abrasive disk of the type adapted for mounting upon a rotatable support, the combination'comprising a wire reinforcing mesh, a body of abrasive material molded about said mesh and defining a mounting face thereon, said mesh being recessed well within said abrasive body, a relatively large collar of non-circular geometric shape partially imbedded within said body and having one exposed face coplanar with said mounting face so as to define therein a stationary bearing area, a plurality of upstanding lugs integral with said collar and projecting through said mesh, said lugs having end portions bent into overlying relation with the face of said mesh remote from said collar, a fastening nut having a shank of reduced diameter engaging said collar, said nut and said shank being rigidly positioned relative to said mounting face for the transmission of clamping stress to the support independently of said abrasive body, said shank projecting axially from said collar through one of the interstices of said mesh, a laterally enlarged head of non-circular cross section integral with the end of said shank remote from said collar and adapted to sandwich thereagainst the marginal portion of said mesh surrounding said interstice.

8. In a reinforced abrasive disk of the type adapted for mounting upon a rotatable support, the combination of a wire reinforcing mesh, a body of abrasive material molded about said mesh and defining a mounting face thereon, said mesh being recessed well within said body, a relatively large collar of non-circular geometric shape partially imbedded within said body and having one exposed face coplanar with said mounting face so as to define therein a stationary bearing area, a plurality of upstanding lugs integral with said collar and projecting through said mesh into interlocking relation therewith, a fastening nut having a shank of reduced diameter rigidly fixed to said collar, said shank having an end face coplanar with said mounting REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,812,076 Beebe June 30, 1931 1,964,537 Shue June 26, 1934 2,425,368 Doremann Aug. 12, 1947

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