US2523698A - Method of making diamond loaded abrasive articles - Google Patents

Description

F. E. HAWLEY Sept. 26, 1950 METHOD of MAKING DIAMOND LOADED ABRASIVE ARTICLES 3 Sheets-Sheet 1 Original Filed Dec. 2'7, 1946 INVENTOR. FLUYU E. HAWLEY AT TORHE Y fieptu 26, 1950 IF. E. HAWLEY METHOD OF MAKING DIAMOND LOADED ABRASIVE ARTICLES Original Fil edDecf 27, 1946 3 Sheets-Sheet 2 2g INVENTOR.

I'LUYDE HAWLEY C; BY

ATTORNEY i atented Sept. 26, i950 UNITED STATES PATENT OFFICE 2,523,698 METfiOl OF MAKING DIAMOND LOADED-"1 A RAsivE Anyiuorcs Floyd" E. Haw'ley, Devon; Con-11., assignor to:

Moore Special Tool (30., Inc a; corporation of Connecticut 1 Original application December 2?, 1946', Serial Ni: 7 718,818. Divided and this applicatioii- Marclrfl 10,1948,Seriallo;14,104

2 ClaimS.. (Civil-293') carbide or the like.

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

Fig. 1 is a front elevational view .of an. upper portion of a grinding machine incorporating the features of the invention;

Fig. 2 is a top plan view thereof;-

Fig. 3 is an end elevational view of the midportion of the machine;

Fig. 4 is an enlarged front elevationalview showing the crusher roll mounting in relation to a grinding wheel;

Fig. 5 is a sectional view taken as along the line 5-5 of Fig. 4.;

Fig. 6 is a sectional view taken as along the plane of the lined- 6 0f Fig. 4;

Fig. 7 is a sectional view takenas alongthe plane of the line .'l-'I of Fig. 4; and

Fig. 8 is a sectional view taken as along the plane of the line 8-8 of Fig. 4.

The present applicationis a-division of my application Serial No. 71-8,818, ,,filed,Decembenfi, 1946. In the parent applicationLclaim the machine herein disclosed, the present application containing claims to my new method .of making 7 diamond loadedabrading devices.

Referring in detail to the drawings andat first more particularly :to Figs. -1, 2 and at 10 is generally indicateda grinding machine includ- .ing a longitudinally movable table I l mounted on a saddle l2 movable in directions transverse to those in which-the .table is movable. .Atthezrear of the table II and saddle l2 .is,a verticaltool post 13 including avertically.adjustablemeans or 2 slide 14. This slide is adapted to be raised and lowered by suitable means, as by a vertical screw t5 dried to the slide.

A hand wheel I6 is fixed with relation to and is adapted. to rotate-a bevelled gear I! meshing with abevelled gear 18 threaded to the screw or shaft 15. Clearly, on turning of the hand wheellfi; the resultant operation of the gears I1 and I8 will cause the screw or shaft 15 to be raised or low ered depending on the direction in which the hand wheel is turned and will cause a correspond, ing movement of the slide I Movable with the slide 14 is a bed -.or block.

=19 to whichcbolts '20 secures, bracket .21, the latterincluding an upper shelf-like portion..2'2,;a-n angularly disposed front wall portion. 23 and la hub-like portion.24 braced by the wall portion 23 and mounting ashaft 25 to which is fixed an abrasive form grinding wheel 26,. that the wheeLZB is located overan suit b e wo k ho1de1.,.as;a magnetic chuck ZLremovably fixedto the table H for movement therewith relative :to

the abrasive wheel 26. Thus, the chuck is adapted for he pporting of. workr o be g ound andathe moving of s ch =W0 k-back an f rth beneath the abrasivewheel. Clearly, the wheel-head described is adapted-for verticaladiustment with the block I9, relative to the chuckand table, on manipu lation of the hand wheel l6.

Mou d o he brack 2;! for e eme t er with and with he ent re whee h ad is a-ib ac et or extension 28 preferably of channel :or other rigid construction,projecting to one side .of. .the bracket 2| and on its upper side at its outer end includinga table-like portionZQ. This portion 2 9 is provided with a ,series of bolt receiving holes or openings ,30 adapted for use in fixing iclainps or other meansin place when :such clamps or other means ,arensed for locating and securing ,a template in place, ,as the template 3-] Integral with "or ,secured to the upper side of the shelf-like portion 22 of thebraclret 2| is. a block or portion, 32 provided with a dovetailway 33 mounting a.. slide .34.; A screw 35 having :a hand wheel 36 or other turnin'gmeans, fixed theret iis ,adaptedto feed the slide Mon the block or portion ,32 directions transverse of .the axis of the abrasive wheel mountingshaft 25., Prefterably, a micrometer scale3l is associated with the wheel .36 ,whereby ,the amount of turning of thewheel and the amount of feedof the slide 34 is accurately shown so that theoperatorwill' It is ha ed thereto or integral therewith is a block 38 provided on its upper side with a dove-tail way 39 having a nut 40 fixed thereto as by means of bolts 4|. On the block or portion 38 and adapted for movement along the way 39 is a second slide 42. Such second slide carries a screw 43 threaded through the nut 40 and provided with a hand wheel or manipulating portion 44 adapted for use in manually turning the screw whereby to feed the slide 42 along the way 39 in directions transverse to those in which the slide 34 is adjusted on manipulation of the hand wheel 35. A suitable micrometer scale may be associated with the hand wheel or portion 44.

Preferably, a suitable locking means, such as one in the nature of a screw, is provided to be operated by the hand or finger piece 45 for looking the slide 42 to the ways 39 in the desired position of adjustment of said slide. Clearly, on release of the locking device 45 and manipulation of the hand piece 44 the slide 42 and all parts carried thereby will be adjusted in directions parallel with the longitudinal axis of the abrasive wheel mounting shaft 25.

The slide 42 includes a forwardly directed portion, integral with the slide or fixed thereto, comprising a pair of arms 45 and 4'! at their outer ends supporting an eye or pivot member 48. As shown, the arms 46 and 4'! are generally below and at the sides of the hand piece 44. The eye or pivot portion 48 comprises a portion of a main pivot 49 suspending a pantograph means generally designated 50 from the outer end portion of the slide 42. The arms of the pantograph means 50 are designated 52, 53 and '54 and it is pantograph arm 5| which is pivoted at 49 to the slide 42. Arm 52 is pivoted to arm 5| in spaced relation to the pivot 49 as at 55 while an intermediate pivot 56 connects the arms 52 and 53. In addition, arms 53 and 54 are pivoted together as at 51 and an intermediate pivot 58 connects the arms 5| and '54. Y

It is here noted that the intermediate pivots 56 and 58 are of the same construction and that the pivot 57 is located intermediate the ends of the arm 53. The portion of arm 5| between the pivots 49 and 55 is designated 59 and the portion of the arm 53 beyond the pivot 51 is designated 60. The relation of the length of portion 59 to that of portion 50 determines the ratio of movement of a tool to that of movement of a stylus as will appear.

In spaced relation to the pivot 55 a shaft BI is rotatably suspended from the arm 52. Toward its lower end said shaft 6| mounts a tool holder 62 and the relation of the parts is such that under the best conditions the shaft supports the tool holder at a level to have such holder present the cutting edge of a tool (as a diamond or other tool) in the exact center line of the grinding wheel 25.

Under some conditions, as when using an octohedron shape of diamond, the cutting edge may initially be below the center line of the Wheel and then as the radius of the diamond is renewed, its cutting edge is higher and finally is slightly above the center line of the wheel. In the present instance, the tool is sometimes a diamond, as when dressing the abrasive wheel 26, and is sometimes a cemented tungsten carbide piece, as when dressing a brass disc as will be described, although it will be understood that any tool suitable for either purpose may be used.

From the free or outer end portion of the arm portion 53 (see Figs. 1 and 2) a shaft 53 is rotatably suspended. At its lower end shaft-63 carries a head-like formation 954 including a portio 65 extending radially with respect to the center line of said shaft and having secured to its lower end a stylus 55 adapted to be turned with the shaft 83 as an axis and to be fed across a working face of the template 3 I, all as will be described, and for the purpose set forth.

Since the tool holder and stylus are both mounted by the pantograph means 53, rectilinear movement of the stylus will be duplicated by the tool holder and owing to the relationship of the arm portions 59 and 60, the movements of the tool holder will be on a reduced scale as compared with that of the stylus.

Stylus 55, as here shown, comprises a metal plate secured against the lower end of the head 54. The forward end of the stylus comprises a rounded or circular portion El, comprising the active por tion of the stylus proper, and the center of the radius of this circular portion is the longitudinal center of shaft 53. The free end portion of arm portion 50 is enlarged by a head-like portion 58 in which the vertical stylus carrying shaft 63 has bearing.

The details of the construction of the various pivots 55, 56, 57 and 58 are fully set forth in the application of Frederick C. Victory and John Robert Moore, Ser. No. 555,952, filed September 27, 1944, and now matured into Patent 2,452,599. However, it is here noted that pivot 55 includes a stud 89 comprising an extension of or the upper portion of the shaft 6i, pivot 55 includes a stud H5, pivot 5? includes a stud H, and pivot 58 includes a stud 12 corresponding With the stud Til of pivot 55.

On the shank of stud "Hi there is mounted a bell crank '53 adapted to turn freely about said stud. Fixed to the stud or shaft 63 carrying the stylus 66 is a lever 14 while fixed to the stud B9 of the tool carrying shaft 5! for turning movement therewith is a lever 15. Bell crank 13 includes arms 16 and ll of which the arm 76 is connected with lever l5 by a link 18 pivoted at its respective ends to the arm and lever and similarly a link "5'9 is pivoted at its respective ends to the bell crank arm 7'. and the lever '54.

Fixed on the shaft 63 is a hand lever 80. With this construction, it will be seen that on turning of the shaft 63 (and thus the stylus 55) the lever 14 will be shifted and through the link EB, bell crank '63 and link 18, will impart a similar move ment to the lever T5. As this lever is fixed to the stud GS of the tool carrying shaft Bi, it will be understood that turning of the shaft 63 about its axis results in the exact same movement of the shaft 5! about its axis.

Thus, by means of the described linkage connecting the stylus supporting shaft 63 and the stud 69 of the tool (diamond) supporting shaft 6!, the angular orientation of the stylus normal to the working face of the template governs that of the diamond or other tool relative to a given object, in this case the face of the wheel or disc being dressed.

The shaft-6| is suspended from the arm 52 and necessarily has rectilinear movement therewith and also has turning movement relative thereto as influenced by the linkage construction above described. However, shaft 6! is ac tually supported independently of arm 52 whereby the weight of the pantograph and any force applied thereto will not and cannot cause movement of the shaft such as to force the tool holder 62 toward the wheel 26.

This is more fully disclosed in the above mentioned application of Victory. andMoorebutlhere the means I for the described: purpose is shown. as;

tions 84 secured to orcast with the bracket 2i above described.

Arms 82 and 83 are pivoted together as at 85.:

and it will be understood that'the entire bracket:

8| may be swung horizontally through pivotal Said bracket includes arms" 82 andmounting on the ears- 84' and that the bracket arms'may have relative pivotal movement in the pivotal connection 85. The shaft 6! is rotatable in the bracket arm 83 but it will be clear that the bracket supports the said shaftagainsttilting movement, such as might occur if only the pivot 49 was depended upon to support theene tire pantograph structure. The Weight of the pantograph and any force applied thereto. will not cause tilting of the shaft 6| in a, manner to carry the tool holder 62 toward: the grinding wheel 26.

The structure as above described, with the exception of the slide 42 and its particular construction and the particular means for adjust ing it, is all more fully set forth in theVictory' and Moore application above identified. It thought that the operation and mechanism so far described will be understood, but briefly it is I pointed out that as the stylus 68- ismoved with respect to the template 3!, thediamond on other tool carried by the holder 82 will be given the exact same movement with respect tothe wheel 26 or other wheel or dis-c mounted on the shaft 25.

According to the present invention, combined with the wheel dressing means above describedis a hardened, shaped crushing roller which may be used for crushing a grinding wheel to the desired contour and according to the method of the invention for another purpose. In the present construction, such roller is mounted for swinging movement whereby it may be readily and quickly moved into and out of operative position and means for mounting and positioning the roller and adjusting it are provided. The roller is provided of a shape depending upon the shape of the abrasive wheel to be crushed, and while for that operation a serrated rollerihay beused, for thesecond purpose above suggested a smooth roller is-des-ired. I

According to one method of use of the crushing roller, the pantograph mounted diamond or other tool is first used to give the abrasive wheel 26 the desired'contour. Thereafter the dressed wheel is used to'grind this exact contour into the crushing roller. The reverse of the desired con tour of the grinding wheel may be ground into a hardened, cylindrical dressing roller when but a shallow form isrequired. Otherwisathe hardened crushing roller should be roughed approximately to shape and then finished ground by the dressed wheel 26 to the exact reverse contour. In either event, the crushing roll having been ground to the desired contour, it is moved away from the grinding wheel 26 and the machine used in the customary manner for form grinding. I As the abrasive wheel begins to wear, contact is again established between the wheel and'the hardened crushing roller and the latter is used to dress the abrasive wheel. This latter oper ation may be repeated as often as desired until the crushing roller begins to lose its, true shape, whereupon the abrasive Wheel is dressed withthe diamond or other tool and" then used to-again dress the crushing roller. In this way, a considerable saving is effected on thediamond or other tool since the abrasive wheel between the dressings with the diamond or other tool will be dressed a number of times by engagement with the crushing roller.

To the desired end, an arm generally desig-- nated 86 is pivotally mounted on the bracket 2 I; This arm is pivoted intermediate its ends and at its lower end supports a crusher roller 8'! positioned tobe brought against the abrasive wheel 26 and to be swung outwardly away from the same asthe arm 86' is rocked inone direction or the other on itspivotal' mounting. The pivotal: mounting for the arm 86 is shown in detail in Fig. 6 and will later be fully described.

At its lower end said arm includes a cyli'ndricalhead-like portion 88 the ends of which: are closed by bearing plates 89 and 98 which bearing plates serve to mount. a shaft 8| having the crushing roller 81 removably mounted thereon and located as between washers 92 and held in place by nut 93. Between the bearings 88 and 98 the shaft 9| is of enlarged diameter whereby it includes shoulders 94 engaging such bearing members to the end that the shaft is held against endwise movement.

Fixed on the shaft 9| within the head 88'is a worm gear constantly meshing with a worm ear 86 connected to be driven by an electric motor 91. The shaft of said motor passes through a tubular housing 98 andis pinned or otherwise fastened to a coupling element 99 (see Fig. 5) which is likewise connected by a pin and slot connection I88 with a coupling element MI integral or fixed to the worm 96. With this construction it will be clear that whenever the motor 91 is energized the crushing roller 8'! will be driven and the same is driven at a relatively lowspeed.

Threaded through the upper portion of the arm 86 is an adjusting screw I82 the inner rounded end portion I83 of which constantly bears against a cam I84 formed with or secured to an elongated tube or sleeve I85 turnable on a stud I86 threaded into a socketin the face of the bracket 2| as shown at I81 (Fig. '7). The sleeve I85 is located between Washers I88 and I88 and a nut H8 threaded'on' the outer end of the stud I86 may be reasonably tight against the washer I89 so that the sleeve I85 will be frictionally held in any position to which it may be turned on the stud. For convenience in turning of the sleeve and thus the cam I84, the former is provided with an enlarged'head-like portion III.

With the described arrangement, when the sleeve I85 is turned to dispose the high portion of the-cam I84 under the rounded end I83 of the screw I82, the arm 86 is rocked-in a manner to bring the crushing roller 81 inwardly into engagement with the abrasive wheel 26. When the low portion of the cam is under the inner end of the screw I82, the arm 86 may rock in the opposite direction or in a direction to carry the crushing roller 81 outwardly away from the abrasive wheel 26. Thus, the crusher-roller is easily, quickly and accurately brought to active position and easily and quickly moved from such position.

Preferably means are provided for automatically swinging the arm 66 and the parts carried thereby to such outward position when the sleeve I85 -is-turne'd to present the low portion of cam I84 to the screw I82. To the desired end, a

'7 bracket H2 is shown as fastened to an edge portion of the bracket 2| and a bracket or clip H3 is fastened to a portion of head 88. A coil spring H4 is anchored at its respective ends to these brackets and the construction and arrangement is such that this sprin is constantly tending to rock the arm 86 in a clockwise direction or in a direction to carry the crushing roller 81 away from the abrasive wheel.

Assuming that the screw I02 is so adjusted that the crushing roller will be forced against the abrasive wheel when the high portion of cam I04 is brought under the screw, then in order to bring the rolleragainst the wheel it is but necessary to turn the sleeve I05 to present the high portion of cam I04 to the inner,

end of screw Hi2 (see Fig. 4) when the crushing roller is forced against the abrasive wheel.

After the abrasive wheel has been dressed, the sleeve I05 is partially rotated so that the low portion of cam I04 ispresented to the inner end of the screw I03. At such time, the spring H4 causes rocking of the arm 86 in a manner to keep the inner end of the screw against the cam and to shift the crusher roller outwardly away from the abrasive wheel.

The pivotal mounting for the arm 85 is generally designated H5 (see Fig. 6) and prior to entering into a detailed description of the machines operation, the details of such pivotal mountin which is also an adjustable mounting, are here given. Mounting 6 I5 includes a tubular opening H6 formed through the bracket 2I and in which are located a pair of bearing sleeves III rotatably and slidably mounting a hollow member H8 comprising a tubular portion H9 located in the bearings and an outer portion I of less diameter than the portion H9 and hav ing a shoulder E2I at its inner end. The arm 86 is disposed on the reduced diameter portion I20 of the member II8. A cap I22 closes the outer end of the opening H6 about the tubular part H9 and holds a bearing sleeve within such opening. The inner end of the opening is closed by a cap I23 which includes an inner tubular portion I24 having an in'turned flange 25.

A nut or cap I20 is threaded in the outer end portion of said tubular portion I24. Received by said tubular portion and located between its flange I25 and the cap I25 is a block I2! serving as an anchor for the inner end of arotatable bar I28. Since such bar includes a shoulder i259 against the outer side of the block I27 and has a nut I30 threaded thereon and against the inner side of said block, it will be clear that the 1 bar is held against longitudinal movement by the block. However, the bar may turn relative to the block. Y

Bar I28 is of considerable length and extends outwardly through the member I 58. On an outer portion of the bar is a tubular stem I34 turnable relative to the bar and fixed to the arm 86 as by screws I32. Fixed to the extreme outer end of the bar I28 is a hand piece I33 includinga tubular portion I34 overlapping the outer end of the stem I3I and a head portion I35 adapted to be gripped to turn thebar. Within the reduced diameter (portion I20 of the member H9 is a nut I36 through which the bar I28 passes and having threaded engagement with the intermediate portion I31 of said bar. Nut I36 being located between the inner end of the sleeve I3I and an internal shoulder I38 of the member H8 is incapable of movement longitudinally relative to said member. A

the parts will move together as a unit.

8 set screw I39 passes through the intermediate portion of the arm 86 and the reduced portion I20 of member H8 and at its inner end bears against a locking lug or block I40 having threads formed thereon to mesh with the threads I31 of the bar I28.

With the described construction, it will be understood that on the screw I39 being tightened as the arm 86 is rocked to carry the crushing roller 81 toward and from the wheel 26, the entire pivotal mounting II5 will be rocked and all However, this mounting of the arm 86 includes an adjustment for shifting the arms in the direction of the longitudinal axis of the shaft 25 so as to dispose any particular crushing roller in line with any particular thickness of abrasive wheel.

Thus, on loosening of the screw I39 and turning of the hand piece I35, the bar I28 will be rotated. However, such bar may not move longi-.

tudinally, being anchored by the block I21. Therefore, as the bar is turned, the nut I36 will be fed along the threads of the bar and will shift the member H8 inwardly or outwardly in the bearings H'I locating the arm 86 in the desired position. Thereafter, the screw I39 is tightened to lock the parts in this new position.

In employing the means of the invention, when a new crusher roller is being placed in operation, its contour will be machined approximately to that desired. Now the hardened crusher roller i brought into contact with the periphery of the abrasive wheel. At this time, the crushing roller is power driven by the motor 91 but only at a slow speed and the grinding wheel 20 is driven only by contact with the crushing roller. Continued feeding of the crusher roller into the wheel produces on the wheel the obverse of the contour of the crusher roller on the wheel face.

This results in a savings in the use of the diamond or other tool carried by the pantograph means and further results in rather rapidly bringing the abrasive Wheel to approximately the desired contour. The roughed out abrasive wheel is thereafter dressed in the conventional manner using the pantograph means. The freshly dressed wheel being now exactly correct in contour, the crusher roller is ground by the wheel to an exact shape. This is accomplished by bringing the crusher roller into contact with the abrasive wheel while both are power driven, the crusher roller at this time being also driven at a relatively slow speed.

The crusher roller has been shifted into engagement with the abrasive wheel by turning of the cam I00, the screw I02 being properly adjusted to have the cam force the rolleragainst the wheel. Also, it will be understood that the member H8 will have been properly adjusted longitudinally for locating the crusher roller in radial alignment with the wheel. After the crusher roller is properly shaped, the cam is further rotated or is shifted back to bring its lower point under the inner end of the screw I02 whereupon the spring H l rocks the entire crusher roller mounting in a clockwise direction to carry the crusher roller away from the abrasive wheel.

The formed abrasive wheel is now used in the regular manner and the crushe roller is ready for use to redress the abrasive wheel whenever necessary. One advantage of dressing the abrasive wheel by bringing the crusher roller against the same is that a freer grinding surface is generated on the wheel by action of the crusher roller. There is the additionaladvantage ofsaving wear on the pantograph mounted diamond or other .tool. Further, the cooler grinding action obtained when using the roller crushed wheel results in less heating and distortion of the work piece. This permits of the grinding of greater contour widths than would otherwise be possible without abnormal heating and distortion of the work piece.

When the crusher roller becomes worn or needs restoration of detail; it is re-ground as previously described by regenerating its. contour with a freshly dressed abrasive Wheel or with a Wheel that has been freshly dressed using the pantograph means. When, in any instance, the roller crushed grinding wheel fails to reproduce suffi cient fidelity of detail on the work, the wheel'is dressed directly from the template by means of the pantograph mounted diamond or other tool providing greater accuracy through elimination of the intermediate step of grinding the roller and thereafter using the latter to form the wheel.

In all of the described operations the maintenance of relative locations of the contour on the template, wheel, cru her, roller and work is inherent in the construction of the device. All of these structures, with the exception of the template, are mounted on the bracket 2! or on the table Ii. Thus, any adjustment of the entire nantograph means by adjustment of the bracket 25 identically adjusts the wheel ZB-and the roller 81.

The machine provides for the enjoyment of the advantages of either method of wheel dressing; that is, by the diamond or by the crushing roller, the structure for the performance of both methods being incorporated in the same machine and being quickly available for optional use without loss of relative location. The present construction permits the contour to be ground on the crusher roller while it is mounted on the hearings on which it is mounted when it is used to crush the wheel. This provides for accuracy by eliminating the errors resulting from changing the roller from one shaft or bearing to another.

To sum up briefly the advantages of the present construction, it is pointed out that heretofore forming of wheels for contour grinding has been done by either of two methods; namely, (1) roller crusher dressing; and (2) diamond dressing. There are inherent advantages and disadvantages in both methods. The present invention rovides for or facilitates the use of either method at any time the operator may choose. This permits the operator to easily take advantage of the method most desirable at any particular time or for any particular job.

The entire pantograph means and the parts mounted thereon, together with the entire crushing roller means and its associated parts. are mounted on the movable wheel head so that when the latter is adjusted the dressing mechanisms remain in the same relation to the abrasive wheel as previous to any such adjustment. Movement of the slide 34 by the calibrated screw means described causes feeding of the entire pantograph means into or toward the abrasive wheel a measured amount or an amount readily determined from a reading of the micrometer scale 31. This feeding of the slide 32 moves the tool or diamond toward the abrasive wheel and governs stock removal therefrom.

However, it is pointed out that the arm 86 and the crushing roller means carried thereby are carbide tool or the like in the holder 62.

not mounted on the slide 34 but are mounted on tourson the side of the latteras well as on the edge or face thereof, when such is necessaryQor desired.

However, adjustments of slide 42 have nobeare ing on the crushing roller and its associated parts since regardless of any adjustments of said slide, the crushing roller and associated parts remain in the same relation to the grinding wheel. The mechanism as already described may be used for the abrading of cemented tungsten carbide and the present invention includes a method of forming an abrasive device adapted for the form grinding of {cemented tungsten carbide. v

My present invention includes an improyed r ethod of making diamond loaded abrasive articles especiall adapted for the form grinding of cemented tungsten carbide articles or .articleslo'f other tough material. According to my method, a disc or wheel is provided and at least the outer periphery of the same is of a relatively soft metal or other material. Such peripher is form dressed or dressed to the desired contour and then my crushin roller, which is of complemental contour, is used to force diamond dust into such dressed periphery. The periphery of the wheel or disc or other article is of a material softer than that of my hardened and formed crusher roller and such periphery is dressed as by the diamond or another tool in holder 62.

When cemented tungsten carbide is to be form ground, a disc or wheel of brass or similar metal is mounted on the shaft 25 in place of the abrasive wheel shown. Such disc may be previously rough- 1y dressed to the desired contour and if so, it is finished dressed by use of a cemented tungsten Such tool, of course, will be operated through the pantograph means. When the brass or other disc is properly formed, the formed crusher roller is brought in against the edge of the disc and diamond dust placed on the edge of the brass disc.

This diamond dust is forced into the disc by the hardened and formed crusher roller. Thereafter cam E04 is shifted to permit of spring H4 carrying the crusher roller awa from the brass disc and the latter is ready for use in the form grinding of cemented tungsten carbide. When the brass disc loses the detail of its form, it is necessary to cut away its periphery since while some diamond dust remains in its peripheral portion it may not be properly dressed. Its periphery is again formed and diamond dust spread thereon and forced therein by bringing the hardened, formed crusher roller thereagainst as previously described.

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

l. The method of making an abrasive article for the form grinding of cemented tungsten carbide and the like comprising mounting an abrasive wheel and a hardened roller on parallel axes, rotating said abrasive wheel at relatively high speed and while rotating the same accurately dressing its periphery to the exact inverse of the contours desired in the finished article, then relatively moving said roller and abrasive wheel and bringing their peripheries into engagement and driving them at difierent speeds to have said abrasive wheel accurately grind into the periphery of said roller the exact contours desired in the finished article, relatively moving said abrasive wheel and roller to separate their peripheries, removing said abrasive wheel from its axis and mounting on said axis a second Wheel having at least a periphery of softer metal, rotating said second wheel at relatively high speed and while so rotating the same accurately dressing its periphery to exactly the contours of the dressed abrasive wheel, spreading diamond dust on the formed peripher of said second wheel, and bringing the complementary formed peripheries of roller and second wheel into engagement and relativel rotating them and by the high unit pressure of the line contact between them embedding the diamond dust in the formed periphcry of said second Wheel by reason of the hardness of the periphery of the roller as compared with the hardness of the periphery of the second wheel.

2. The method of making an abrasive article for the form grinding of cemented tungsten carbide and the like comprising accurately dressing the periphery of an abrasive wheel to the exact inverse of the contour desired in the article to be ground, using such abrasive Wheel to accurately grind into the periphery of a hard roller the exact 12 contours desired in a finished article, accurately dressing the periphery of a second wheel having at least a soft metal periphery to the exact contours of the dressed abrasive wheel, mounting said second wheel and said roller for rotation on parallel axes, spreading diamond dust on the periphery of said second wheel, and relativel rotating the formed second wheel and formed roller with their complementar peripheries in engagement whereby by the high unit pressure at the line of contact between them to embed the diamond dust in the formed softer metal periphery of said second wheel.

FLOYD E. HAWLEY.

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

UNITED STATES PATENTS Number Name Date 151,847 Cochran June 9, 1874 190,115 Babcock et 1. May 1, 1877 261,198 Barton July 18, 1882 1,513,757 Hanson Nov. 4, 1924 2,135,202 Scrivener Nov. 1, 1938 2,226,608 Gilmore et al Dec. 31, 1940 2,377,241 Kavle May 29, 1945 OTHER REFERENCES Diamond Powder as a Lapping Compound, Machine Tool Blue Book, vol. 40, pages 245-248.

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