US2616229A - Abrasive wheel - Google Patents

Description

Nov. 4, 1952 H. v. ALLlsQN 2,616,229

ABRAsIvE WHEEL Filed April 1o, 195o 2 SHEETS-Smm 1 "E ff A HM) il- INVENToR. a HUGH VALLISUN ATTURNEY 2 SHEETS- SHEET 2 F'I g. 14'

INVENTOR. HUEH VALLISUN Y MA.

ATTORNEY Patented Nov. 4, 1 952 ABRASIVE WHEEL Hugh V. Allison, Fairfield, Conn., assignor to The Allison Company, Bridgeport, Conn., a corporation of Connecticut Application April 10, 1950, Serial No. 154,944

13 Claims.

This invention relates to new and useful improvements in abrasive articles and has particular'relation to abrasive cut-off wheels.

`Anobject of the invention is to provide an abrasive cut-oiT wheel including an outer usable abrasive rim member and an inner permanent mounting hub, both of improved construction, whereby a worn down rim member may be readily removed and replaced with a new one.

' Another object is to provide an improved abrasive rim member for an abrasive cut-oil wheel and an improved method of making the same.

A further object is to provide an abrasive cutoff wheel of the character set forth and including means whereby a worn rim member may be removed from the hub and replaced by a new rim member, all from the front side of the Wheel.

Other objects and advantages of the invention will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawings wherein satisfactory embodiments of the invention are shown. However, it is to be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

In the drawings:

Fig. 1 is a rear elevational View showing an abrasive cut-olf wheel made in accordance with the invention;

Fig. 2 is a transverse sectional View thereof, the View being taken as along the line 2--2 of Fig. 1;

Fig. 3 is an enlarged rear elevational View of a small section of the wheel to show construction details;

Fig. 4 is a detail sectional view taken as along the line 4--4 of Fig. 3;

Fig. 5 is a rear elevational view of the abrasive portion or abrasive rim member of the wheel;

Fig. 6 is an isometric view showing the rim member sections separated but in positions for assembly;

Fig. 7 is a front elevational view of the front side or face of the hub;

Fig. 8 is a View similar to Fig. l but on a smaller scale and showing a modification;

Fig. 9 is a detail sectional view taken along the line 9-9 of Fig. 8;

Fig. 10 is a View similar to and on the scale of Fig. 1 and showing another modification;

Fig. 11 is a front elevational view of the wheel of Fig. 10;

Fig. 12 is a transverse sectional view taken as along the line I2I2 of Fig. 10;

Fig. 13 is a rear elevational view of a small section only of the wheel on an enlarged scale;

Fig. 14 is a detail sectional view taken as along the line I4-I4 of Fig. 13;

Fig. 15 is a rear elevational view of the abrasive rim member of the wheel of Fig. 10; and

Fig. 16 is a front elevational view of the hub of the wheel of Fig. 10.

Referring in detail to the drawing and at first more particularly to Figs. 1-7, the improved abrasive cut-off wheel there shown comprises essentially an outer rim member generally designated I0 and a hub member generally designated I I. Rim member I0 is shown as an abrasive annulus and has an annular outer periphery, although it could be differently shaped on its inner periphery. The rigid driving hub I I is preferably of a light Weight metal and has its outer peripheral portions shaped to correspond with the shape of the inner peripheral portions of rim member I0. As will hereinafter be set forth in detail, the rim member l0 is detachably mounted on the hub member II and is driven by the latter. With this construction, when a rim member wears ydown to the point where it is no longer of a diameter to be economically used, the worn rim member is removed from the hub member and replaced by a new full-sized rim member.

Rim member I0 is a laminated structure made up of a front layer and a rear layer. The front layercomprises a plurality of arcuate sections or elements I2 and I3 of an annulus while the rear layer consists of the arcuate sections or elements I4 and I5 of an annulus. In actual practise, rim I0 will, in many instances, be of relatively large outside diameter as, for example, a diameter of 36 inches or even more. Additionally, it is to be understood that the layers of the rim I0 may each comprise more than two segments and in fact, the rim may be made up of more than two layers.

The manufacture of a large diameter abrasive rim member by methods heretofore generally practised would involve the use of large and expensive equipment, not available to the smaller manufacturers of abrasive cut-off wheels. The present invention provides a method whereby the rim I0, of substantially any desired diameter, may be made without the necessity of the manufacturer providing himself with large expensive equipment. The rim I 0 resulting-from the practise of the above indicated novel method has many desired characteristics.

In manufacturing the rim member I0, I prepare the sections I2, I3, I4 and I5. Such sections are in the nature of strips curved edgewise so that each comprises approximately lk an annulus. The strips are of abrasive grain and a suitable bonding medium. The cure of the bond is generally determined by the use to which the abrasive cut-off wheel is t be put and thus the bond may be resinoid or rubber or of a combination of such materials.

In making the rim member, strips may be rolled out and the sections died therefrom. Then the sections I2 and I3 will be arranged with their adjacent ends slightly spaced as in Fig. 6y

but with their outer edges defining substantially a complete circle. Thereafter, the sections I4 and I5 are placed on the sections I2 and I3 in staggered relation with the latter but with the end portions of the sections I4 and I5A also slightly spaced.

In this assembly. a mid-portion of the section i5 will overlap the space between a pair of adjacent ends of the sections I2 and I3 whilea midportion of the section I4 will overlap the space between the other pairs of ends of the sections I2 and i3. Then the mid-portions of sections l2 and I3 span the spaces between the pairs of adjacent ends of the sections I4 and I5. This staggering of the sections of one layer with respect to those of the other layer provides a rim member in the form of an annulus having through its rear face a pair of radially extending channels I6 and Il extending from its inner through its cuter periphery. Additionally, in the rim member the spaces between the ends of the sections I2 and I3 of the front layer denne a pair of channels I8 and I9 through the front side of the rim member and extending from the inner periphery of the front layer to the outer periphery thereof.

rfhe layers of the rim may be assembled green or -prior to complete curing of the bonding medium although in a cured state they may be assembled with the use of proper adhesive. The layers Vare so assembled that their outer peripheries are substantially flush with one another. However, the sections i2 and I3 of the front layer are wider than are the sections I4 and I5 of the rear layer and thus the inner edges of the layers are not ush with one another. For example, in Fig. 5, the inner edge of the layer made up of sections Ill and I5 is of much smaller diameter than is the inner edge of the front layer made up of the sections I2 and I3. This results in the formation of a recess 29 of a depth equal to the thickness of one of the segments I4 or I5 and opening through the rear side of the rim member and through the inner peripheral edge thereof.

A series of short rigid studs 2I are rigidly attached to the portions of the front layer exposed through the recess 20. In a completed wheel, the mentioned portion of the frontlayer of the wheel is overlapped by the outer peripheral portion of the hub il, as will be set forth, and thus in a completed wheel the studs 2| are carried by a portion of the rim member which is overlapped by a portion of the driving hub member. These studs are not abrasive or do not comprise a mixture of abrasive grain and a bond but preferably are of metal or a hard tough resin suitably adhered to the defined portion of the rim member.

For a purpose to be described, one or more of the studs is provided with a reduced diameter portion which is adhered to the rim member whereby there is a spacebetween the outer portion of thestud and the rim member. In the wheel shown in Figs. 1-7, a pair of diametrically opposed studs, designated 22 and 23, have such reduced diameter portions whereby there are spaces or openings 2Q and 25, respectively, between larger oiameter heads of the studs and the rim member. The studs may be attached to the rim member either beioreor after final curing of the bond of the latter. Preferably, the studs are positioned while the sections of the rim are yet green and are placed in the curing chamber with the other elements of the rim. During the curing, the abrasive mix of the sections may shift or slightly shift the studs, but it is noted that if the holes (to be described) in the hub member are slightly oversize, accurate location of the studs is not too critical. A driving connection between the hub and rim members will be established as hereinafter described.

It will be understood that when the sections areassembied to form the rim member priorto nal curing of the bond, during the final cure, the sections of one layer will become bonded to those of the other layer. Thus, a substantially homogeneous structure is provided.

In this way, the bond between the sections 'of cnc layer and those of the other layer will-be 'of the strength of the bond securing the grain in piace and willhave an equal useful life. It will be understood that the final cure will depend upon the bond employed. For example, if the bond is of rubber it will contain sulphurY and other necessary ingredients and the rim member will be vulcanized. If thebond is resinoid. the rim member will be cured by a process [for accomplishing the desired cure.

The hub II includes a larger diameterportion 26 of a diameter tobe received in the recess 20 of the rim member and concentric with the sportion 26 includes a thicker portion 21 of smaller diameter. Here portion 2'I is shownasadisc formed separate from the portion 26 and the portions are secured together in any desired manner but in concentric relation Aso that an annular shoulder 28 is formed.

A shaft portion or stud 29.may.be formed with the hub portion 26 and portion 29 may be adapted to be held by a chuck or thelike or may -be other- Wise driven and, in fact, may be apermanent part of some driving mechanism.

Through the hub portion 26,. aseries of holes 3i) are formed. These holes will correspond in number with the number ofstuds 2|, 22 and 23 and are of diameters to receive such studs. In assembling the present wheel, yassuming that the hub II is part of a machine, the rim-member I3 is disposed at the forward side of the hub withY the studs of the rim member entering the openings 30 through the larger diameterportion 2S.

of the hub and wlth theY hub portion 21 being received within the inner periphery ofthe lforward layer of the rim member. lIt will be clear that the outer peripheral-portion or hub part 26 is received in the recess 20 of the rim'member.

With particular attention to Fig. 2, -it will be seen that the hub II is ofa thickness to be received between or within the planes-dencd'by the front and rear surfaces of the .rim member. Conveniently this 'is accomplished by having the larger diameter hub portion 26 of a thickness equal to or slightly less than that of the `rear layyer ofthe rim member and by having the smaller diameter hub portion 21 of "a thickness equal to or slightly less than that of the two layers of the rim member. With this construction, the wheel is adaptedto cut .through.a;work

piece of a diameter greater thanthe widthof the abrasive `wheel rim. This is true since the thin metal driving hub of the present wheel may enter into a cut made by its abrasive rim.

The hub carries means for cooperating with the undercuts of studs 22 and 23 in securing the rim member on the hub against vlateral movement relative thereto. In providing this means, recesses 3I and 32 are provided in the forward face of the hub portion 26. In these recesses are disposed keys 33 and 34- each comprising a flat metal piece having one end` fast to and pivotally mounted by a screw or other turnable pivoting element. In the drawing, key 33 is shown as fast with a screw 35 while the key 34 is shown as fast with a screw 36.

.These keys are rotatable relative to the other portions of the hub member I I and the keys being fast with the screws, it will be clear that as the screws are turned, the keys will be turned. These keys are so located that they may be turned from the released position of Fig. 7 to locking positions in which their free end portions pro- `iect to extend somewhat across a pair of the openings 30 as the pair 30a and 30h, respectively.

In the assembled wheel, the slotted or operating ends of the screws 35 and 36 are at the forward side of the wheel beingl in the thickened central portion 21 ofthe hub. Therefore the hub being mounted and the keys being positioned in the inoperative positions of Fig. 7, a rim membermay be disposed against theforward side of the hub. In doing this, care is taken to have the studs 22 and 23.enter the hub openings 30b and 33a, respectively. Now, through a suitable tool, the keys 33 and 34 are rotated or shifted through a slight increment so as to dispose their free end portions in the spaces or undercuts 25 and 24 associated with the studs 23 and 22, respectively. This entrance of the locking keys into the spaces or undercuts of the studs is fully illustrated in Figs. l-4.

The rim member being disposed on the hub and the keys having been turned to their locking relations with certain of the studs, it will be clear that lateral movement of the rim member from the hub is prevented. Additionally, the studs preferably have rather snug fits in the openings in the hub and serve to establish driving connections between the hub and the rim member. Attention isl directed to the fact that the keys 33 and 34 in their locking positions are in the positions to which they tend under centrifugal action when the wheel is being rotated. Further, it is noted that thestuds of the rim member need not have snug ts in the openings in the hub. If there is any relative turning, movement between the hub member and the rim member, one or more of the studs engages the side or sides of one or more of the openings and thereafter the members must rotate together.

When using the present wheel, the slots I6, I'I, I8 and I9 opening through the front and rear faces of the rim member and extending radially serve a purpose in that they provide for the carrying of a cooling medium directly into a cut being made. Where these Wheels operate in a flood'of coolant, as is commercially done with rubber bonded cut-off wheels, the mentioned channels will be filled with the coolant and as each channel successively moves into a cut during rotation of the wheel, coolant is carried into the cut. Sincev circumferentially the channels are alternatelyin opposite faces of the wheel,-it willbe .clear that-coolant willbe carried into the cut successively at alternate sides of the wheel. The formation of the rim members with the slots I6-I9 is a preferred construction. However, it is to be understood that the invention is not limited to such construction as many features of the invention are useful with rim members not provided with slots or other coolant carrying features.v f

It will also be understood that the sections being bonded together in the staggered overlapping relationship shown and described, and the .bond being generally effected in the final curing operation, the wheel is substantially' a homogeneous structure.Y Further, the sections of one layer overlapping the adjacent spaced pairs of ends of the sections of the other layer, there is a mutual bracing or reinforcing of the sections.

When these vcut-off wheels are in use they are rotated at high speeds and where the'wheels are of large diameters it will be clear that many linear feet of a wheel pass through a cut per minute of operation. As the wheels wear down, the mentioned passage of linear feet is naturally reduced and finally a point is reached where efficient operation on a particular job is not had. With the present large diameter hub the wheel is stiff and true running and the abrasive rim is entirely used up so there is no large Istub to be discarded.

With the present wheel, if eicient operation is no longer attained,the screws 35 and 36 are operated to turn-the keys to released position and the worn rim member is removed and is replaced by a' new rim member. The latteris secured in place merely by turning the keys back to locking positions with respect to the stud or studs carried by the rim member. In this connection it will be understood that an interlocking engagement of the key with one stud will prevent lateral separation of the rim member and hub, but generally it is preferred that one such structure be balanced by a similar structure at the diametrically opposite side of the hub. In fact, means may be provided by accomplishing a similar locking between the hub and each stud of a rim member. l

Referring now to the modification of Figs. 8 and 9, the wheel shown comprises an'abrasive rim member generally designated'40 and a driving hub member generally designated 4I. Rim member 40 may be constructed identical with the rim member I0 with the exception that the member 40, in its overlapped portion or in the inner peripheral portion of the sections of its front layer 42, is provided with internally threaded bushings 43. The desired number of these lbushings are employed and they are preferably molded into the material of the abrasive sections so as to be fast therewith.

Rim member 40 being of the construction of the rim member I0 with the exception that the member 40 mounts the bushings 43 rather than studs, it will be understood that the member 46 is made up of sections arranged to provide front and rear layers for a laminated wheel'structure." The ends of these sections-are slightly spaced whereby rim member 40 has the radially extending channels I6, II, IB and I9 exactly as in the rim member I0.

With this construction, the hub 4I may be of a single piece of material of two diameters having thus an annular shoulder 44 to be engaged by the inner periphery of the front layer 42 of the rim member 4I) and having a second and larger diameter shoulder 45- to be engaged by the nieuwe inneriperiphery-fof the zrearglayer--E d6, :of dahe rim member. '.Thus.. f itrwill becseenz` that .theficuter peripheral portion-nf thehub-JII. is .received fin aerecessfiofzthefrim memberf and 'which recess 41 .correspondsy exactly with'the-:recessie ofsthemim member; il).

Through the :outer `peripheral. portion "of :hub 4| which is received in the recess/fipa seriesiof screws'liaaare passed. .These screws will inv number-equal 'the numberor-bushingsfd3. and zto assemble the l"rim-jmembert on the 1 hub :s i the screws 43V Vare `'threaded into the ybushings, .43 drawing the :rimamem-ber and hub -into close. relation. .The .screws and bushing-s establisha drivingY relation between the hub .member and .the rim membersoI that they are incapable foi.v independent;` rotation and they. also serve to ccnnect these members against lateral separation.

In use, thewheel of Figs.v 8 andi) will .be-:einployed in the samemanner as the wheel AofsFigs. 1 7. When a rim member-of thewheel of Figs..8 and -9 isworn down and is to be replaced, .screws GS'are-all loosened and :screwedout ofthe.,bushings 43. Thismay-.be accomplished from the front side =of the wheel v.and `then .la .new rim member is placed on the hub .and thescrews threaded-into the bushingsof.thisv new rmrmember fand ,the wheel is .ready for use. Y The .hub member 4l is of less thickness than the rim member and somay entera cut made by. the .rim member. .Thereforethe present wheelis adapted forthe .cutting through of workofgreater .diameter ythan the .width ofthe rimniember de.

Reierringnow torFigslO-l, the abrasive .cut-

ofir wheel there shown comprises an abrasverim member `generally designated@ and ra central driving hub member generally designated 5i. While the outer .peripheral Yedge .offrim member 5U isa true circle, its inner `peripheral edge portions need not be so and lthe .outer peripheral edge portions of the hub 5i will be complemental to the inner peripheral edge` portions of therim 5D. This wheel will be. used in the same manner as ythe wheels previously described andto that end, as will be setforthin detail, the rim member 58 is removably mounted on .the .hub member 5l. Furthenthis rim n1ember.5l .is -built up: as a laminatedstructure although inthe completed l product is a homogeneous or substantially homogeneous structure .as in .the .case .of the rim members! Uandl.

As rim member .iisvbuilt up it comprises .a

geredrelation with respect tothose-.of .the .other layer whereby the midportionsof .the sections of one layer 'overlap the end .portions of the sections of the other layer.` 'In addition,.the end portions of the sectonsof the respective .layers are slightlyvspaced whereby in the completedV rim member the radially extending channels A6,. Il, I8 and i9 described in .connection withFigs..1-7 are' formed. Y

Additionally, the sections of thevfront layer beingwider than .those ofthe rear layer, a. recess 56 is formed'in therim vmeinber and opens through vone of its sides and through .its inner peripheral edge. The. portion ofthe front .Ilayer defining a side of therecess .56 is in the assembled wheel overlapped by the vouterperipheral portionoithe hub..5| and this overlapped portion of the.l rim membercarries `a .plurality of fstuds A51.

Each vfstud lis .formed `with ia reduced diameter 83; underiportionf5f'awhichris adhered` to thev rim member, Thnseeachgstudzhasai fheadrandibelow such head-fandfaboutsaid reducedrdiameter por,- tion is aispace'forundercut. :Such space loriundercut :is rcircularz: andi nofgcare'zissrequired .in positioning rthe fstuds.. on. ,the rim member.

Atfeac'hiside '.of f each stud `5.1 `:fis-:an -opening 25e. Hubf-,l comprises `:eL-:metallic@oriother` rigid'structurerincluding'anaouterperipheral 'portion 6.0 :of substantially .gthe 1 thickness -of :the 'rear layer of therimfmember.- Then .the hub-includes ,anirmer thickenedrportion Gil :ofiasubstantially the .thickness :.of :ithe fforward, layer f of fthe rim member. Thisihubz-S l ,-iseof fless thickness than @that of ithe rimvmemberaand mayienterauzicutzfmade by fthe rim member wherebyitheswheel s;adaptedstof,cut through a iworkgpieeeaof igreateridiameter z than the width'. of `the zrimxmember150. Portions 63 and 6l betweenizthemf.deneashoulder ewhich is :actuallygthes cutlery-.peripheral edge 2 of rthe portionil.

.Through portion are ppenings-fcorresponding ina number iwithzthe number :.oif fthe studs ,-5? and 01E diametersatorreceiveftheseastnds vto provide a 4driving connection between :the :hub and 1annulus. Ther-studs-y neednot' have zsnug' fits inthe opening Iand ,need rnot '.beflocated :with exact accuracyfcr .the reasons; givenabovefinfconnection with fEigs. ;1--17 Mountede in recesses :in ithezouter hub iportion's atieachgsideiof eachuQpening-GS isa key; such keybeing fastzwith .headedfstudsa which areshown aszpassng throuehfthexeys. Thegstudsiare turnable in thefhub: 5i

lorwardly r"of inheskeys@Sliy slotted nuts ,ori elements-:.EB-iare'ffast `with-tithe studs and :,thus' with the 'rkeys. These elements .orv nuts 'BS may be welded orzotherwisemadefastwith-.the studs and keysfpreferably .by :threadingsof the inutspor .elements fontogthe Shanks bf the I. studs and :then welding, as .finf;lig. l1;4.

With ithisconstruction, the :hub :member 5| which carries-ashaft or ,mounting piece :.G'l.' being position on za; machine,v should-the .abrasive rim lzinember l.Wear :down :so :that .it i. needs -v,to .be replaced,.the-ioperator :standsv atthe forward side of the awheel *,fandxengages :the-*slotted elements e6 withrzthebitcf aiscrew'fdrver-.or the ,likeand turns :them about :their own'iaxes :to `turnithe keys .to released positions y.as .to fthe l.postionsin which they rare shownsin.:=ig.,;16; Allgofzthekeys being in this fpositiomerthexworn -rim Lmember may :be removed fromttheshub simplyiby moving the rim :member laterally forwardly The Vnew rim,..member-i is :theniplacedzon'ithe Yhub andA Ythe studs :5i :.of :.the,rim1.member .are zlined v.with and enter the openingsaiinithehubl At the same time,;;the..-elements. or nutsii of the-hub enter the openingslgcof'zthe rim member. yA1soythe-outer peripheral portionf/Slof the hub" is now inthe-recess 'openingfthrough one side and the innerj periphery'of ythe rim `member andthe 'thickened-hub :portion: 6 I is "within theouter layerofv thel rim Vmember with its shoulder "E2 engaged..or.substantially engaged with the inner l,peripheral .edge of...such front .layer .of the rim.member.

vNow-the.,*operator still standingin .front .of ...the wheel, by-.a screwdriver orsothertool manipulates the-.nuts or/elements'tomotate the keys through approximately l to ..enteritheir .free edge. portions into ythe -.sp aces .about the ,reduced diameter portionss58 of the.studs. '.Thisdocks .the rim mem'berfonto 1the --hubagainst lateral movement from;..ts1.1e..1atter..l auditcwillibercleartthatthe studs 9 51 together with the nuts or elements 56 provide adequate driving connection between the hub and rim member whereby any rotation imparted to the hub is in like manner imparted to the rim member.

In this construction, two keys are entered in the space at the underside of the head of each stud. These keys enter such space at opposite sides of the stud. Since the two keys are used and located as described, the rim may not be tilted'to exert a pry action on a stud such as could be accomplished if but a single key was used in the -location shown. Additionally, it is noted that when the keys are in their locking positions (see Fig. 13) they are against the outer edges of the recesses or walls in which they are located. Therefore, centrifugal action during rotation of the wheel cannot throw the keys out -of their locking positions.

In all the structures shown the stiff metal hub member provides for a fiat stiff true running cutoff wheel of large effective diameter. The present wheel does not run out of true as may happen with larger diameter thin wheels wholly of an abrasive mix. Further, with the headed studs employed in Figs. l-7 and 10-16, they need only be located as there is an annular space about the reduced diameter portion into which a key or keys may enter.

The rim members of the various forms herein are specifically sho-wn as annuluses. However, the inner peripheral edges of the layers of the various rim members could be other than true circles, as ovals or as having angularly related edge portions.'V 'In any such instance, the hub member would or could have correspondingly shaped edge portions.

Having thus set forth the nature of my invention, what I claim is:

1. An abrasive cut-oif wheel comprising an abrasive'rim member having a recess opening through 'one side and its inner periphery, a driving hub of a diameter having its outer peripheral portion received in said recess in overlapping relation with a portion of said rim member, said hub of a thicknessnot greater than that of said rim member whereby to lie wholly between the planes represented by the side surfaces of the rim meinber, laterally extending studs on the overlapped portion of said rim member of a height equal to the depth of said recess, one of said studs deiining a recess opening through a side thereof, said hub having openings receiving said studs whereby a driving connection is established between said hub and rim member, and a key on said hub and turnable relative thereto to and from a position entering the recess opening through a side of said one stud and thereby securing the hub and rim member together in driving relation.

' 2. An abrasive cut-off wheel comprising an abrasive rim member having a recess opening through one side and its inner periphery, a driving hub of'a diameter having' its outer peripheral portion received in said recess in overlapping relation with a portion of said rim member, said hub of a thickness not greater than that of said rim member whereby to lie wholly between the planes represented by the side surfaces of the rim member, laterally extending studs on the overlapped portion of said rim member of a height equal to the depth ofsaid recess, one of said studs dening a recess opening through a side thereof, said hub having `openings receiving said studs wherebya driving.vv connection is established between said hub and rim member, a key on said hub and turnable relative thereto to and from a position entering the recess opening through a side of said one stud and thereby securing the hub and rim member together in driving relation, the side of the wheel wherein said abrasive segments are of the greatest width comprising the front side of the wheel, and means operable from the front side of -said wheel to turn said key to and from a locking position entering said recess defined by said stud.

3. An abrasive cut-off wheel comprising an abrasive .rim member having a recess opening through one side and its inner periphery, a driving hub of a diameter having its outer peripheral portion received in said recess in overlapping relation with a portion of said rim member, said hub of a thickness not greater than that of said rim memberwhereby to lie wholly between the planes represented by the side surfaces of the rim member, ,a series of internally threaded bushings fast in the overlapped portion of said rim member, and a series of screws passing through the overlapped portion of the hub and threaded into said bushings whereby the hub and rim member are detachably secured together in driving relation.

4. An abrasive cut-01T wheel comprising an abrasive rim member having a recess opening through one side and its inner periphery, a driving hub member of a diameter having its outer peripheral edge portion received in said recess in overlapping relation with a portion of said rim member, said hub of a thickness not greater than that of said rim member whereby to lie wholly between the planes represented by the side faces of the rim member, laterally extending lugs on the overlapped portion of one of said members and of a height not greater than the thickness of the overlapped' portion of the other member, one of said studs defining a recess opening through a side thereof, said other member having openings receiving said studs whereby a driving connection is established between said hub member and said rim member, and a key on said member having said openings therein and turnable relative to said member to and from a, position entering the recess opening through a side of said one stud and thereby securing the members together in said driving relation.

5. An abrasive cut-off wheel comprising an abrasive rim member having a recess opening through one side and its inner periphery, a driving hub vmember of a diameter having its outer peripheral edge portion received in said recess in overlapping relation with a portion of said rim member, said hub of a thickness not greaterv than that of said rim member whereby to lie wholly between the planes represented by the side faces of the rim member, laterally extending lugs on the overlapped portion of one of said members and of a height not greater than the thickness of the overlapped portion of the other member, one of said studs having a recess opening through a side thereof, said other member having openings re ceiving said studs whereby a driving connection is established between said hub member and said rim member, a key on said member having said openings therein and turnable relative to said member to and from a position entering the recess opening through a side of said one stud and thereby securing the members together in said driving relation, the side of the wheel wherein said recess opens through the side thereof comprising the rear side of the wheel, and means operable from the front side of said'wheel to turn said key AT11 to.. and from a 4locking positioni entering saldyrecess in the said one stud.

6, An abrasive cut-off :Wheel @Qmpiingfan jabrasive .rim memberhavinga-.reess Opening f through oneside and .its.innerg.periphery, .a dliV- ing hubof a, .dia-meter having .its outer :peripheral portion. received in said vrecess in; overlapping A relation with a portion of .said;rim.member,said .hubofA a thickness not greateizthan thatA .of fsaid rim member whereby to lie wholly betweentthe..

hub for turningtmovement.relativeftheretoto and from .a position entering the .recess .defined by Vsaid' one stud whereby .to receive: thehub and ri-m member together, and the :pvotalfaxis of said vkey `and .the .center otsaidonefstud being substantially in the saine :radial line .passing through the center of said.- wheelwhereby the tendency of centrifugal action-asA said v.wheel is rotated is to maintainsaid key in lockingrelaticn with said one stud.

7. .An abrasive. cut-otfwheel :comprisingan- Vabrasive rim-member .havin-gia recess opening through `one sideand its` inner periphery, a driving hubof az diameter -having .its outeriperiph- .eral portion received insai'ol recess in overlapping relation'with a portion offsaid rim. member, said .hub..of. athickness not greater. .than that .of said -rim member wherebytolie wholly between the planes. .represented bythe side.: surfacesv of the -rim member,.a laterally extendingfstudson the -overlappedportion of said-srimmember ofv a .height notgreaterthanzthe depthof said -recess, :said :stud dening openings through its. opposite sidese saidhub having an. opening .receiving said 1 stud whereby :a' driving connectionjs established vbetween' saidhub .and saidrimfmemberf a pair of keysxa paircof .depressions in lsaid-hub `one at each .side .of saidv opening fand .entering lthrough the opposite side of the latter, .mea-nspivotally mountingv said keys. one ineacheofsaidl depresg'sionsg for 1 turning movement 1 .relative `to the hub tmand from positions entering fthe recesses de- :nedfby isaidstudwhereby to 4secure'the Vhub and :grim-:member .tegethensaid .keys locatedewhereby as said.l wheel is: rotated centrifugal action'itends f to move. said keysintthe 'recessesl deinedV bysaid stud; and said depressions located whereby their side .edges lim-it fsuchfmovements- :of fthe keys to movements v-to locking .relation -fwith .saidstuds.

:8. AVAn abrasive cut-.oit vJhee1= -.comprising an abrasive .rim member .havingfa recess- 4epei'iing through. one side. and itsinnerperiph'ery, f adriving hub of. a diameter having.,itsioutertperipheral portion receivedin said recess-in :overlapping relationwith alportion ofsaid rimv member, said hub .ofl a thickness notgreaterv .than that vof-said rim member Wherebyto lie wholly,between .the planes represented by .the.sideesurfacesfof the rim member, alaterally.extendingstud on the overlapped portion ,of-...said rim .member .of a height not greater thanthe depth.;of..said..recess, said. stud dening an openings-through va lside thereof, saidhub having yan opening receiving Usaid stud whereby. a driving. eonnectionisestablished between said. huband said .rim.member, sa

of -..-each-. naira. having their: pivots located .at respeetively the .oppcsite sides orsaid studs and'in :recesseslimting swinging, movements of thelkeys.

...ken a depression'insaid hub aticnesidepi said opening.:andienterinsithrouglna sdefoflthelstter, means. pivotally i mounting .said key in. said depressionfor turningmovement relative Vtothe hub to and from a position enteringrthefrecess .defined byI said vstud wherebygtoesecure the hub and rim member together, said key located wherebyl as said wheel is :rotated centrifugal actiontends te movesaidflgeyintothe recesssdened byeseidstud.. and. said. .depression located-whereby :its :side edeeslimit such movements of itbeikey tof movements to. locking: relation with. said stud. 9@ An.; abrasive z. cutoff wheel .cemnrsl. s an ...abrasive .frime-member .in .the r forni-.of .an nnulus .-1 hai/ginge. a.- r .its :inner periphery; a driving hub-.meme diameter having its .cuter-peripheral partie r p ceivedfin Seide-recess in. .oyerlappinefrelation with the inner peripheral portion ofgsaid rim member, said. hub ...membervoi a Vth.witness .Tnet .sr-eater thanpthat or :said/rim member f-Wherebyito lie lwholly V- between Vthe planes represented@ byI the .f-side surfaces vof .thefrim .membeiufmeans .comprising crcuinferentiallyfspaced:.means in the oyerlapped portions of. .one Of-vsaid .irlerilbers ciretmivferentialgly -spaced studs extendingA laterallyfrom 2the overlappedportion-o theother-member and :passing through said recesses, heads on the outer ends of said studs, and key meansqonthe overlapped portion of ithe recess carryingfmemberand 'pivoted for swinging mov-ement to extendv under said headsv and lock saidv members together :and for movementroinunder said heads :to release vsaid-:studs foriseparation of saidmembers.

l-Thecutofi wheel :as in-claimrQ including two of :said keystor eachv of said `studs and said keys of each pair havingtheir pivots located. .at respectively the cpposite'sides of said studs.

1l. The cutof wheel as in claim9 including. two of said .keysfor-eah of ,said studsand said `keys 112.- YAnA .abrasive :cutfeff wheei comprising an :.abrasve -rimmemberhaving anon-ter peripiieifm :cutting surfaeeand .sidersurfm parallelism Y equidistant .f romyeachotherf whereby :said cuter peripheral cuttingsurface remains of equal `width as .its diameter. decreasestbroughwear, a .driving .hub detachably; mounting. ,seid--rim member and lying ywholly within vthe,.p.1'ir1.es.represented..by Said side surfaces, .andsecurine `means.cooperatively connected between said rim. member jmd hub. detachably lsecuringgthem.against.relative .axial and rotative Adisplacement and .disposed Wholly Within saidplanes whereby thefmaximiim cutting depth offsaid cuttingsurface is greater than the radial distance-between said cuttingfsurface .and Isaid securing means.

13. An Aabrasive Vc,1.1t oi.whee1 .dmprising an Y abrasive-.rim member the jor-m of anannulus 4ine .its- Guter. .peripheralfpertion.'detaehablyifreoeved in said recess in overlapping relation with the base of said recess, said outer peripheral portion of said hub being of a thickness not greater than that of the inner member and lying wholly within said parallel planes, and securing means cooperatively connected between said recess part of said rim member and said outer peripheral portion of said hub detachably securing them against relative axial and rotative displacement and disposed wholly within said parallel planes, whereby the maximum cutting depth of said cutting surface is greater than the radial distance between said cutting surface and said securing means.

HUGH V, ALLISON.

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

UNITED STATES PATENTS

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